CD16a-binding polypeptide

Abstract

The invention provides a CD16a-binding polypeptide, which comprises at least one motif that binds to CD16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]-[Helix 2]; the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule. The invention also provides pharmaceutical compositions comprising the CD16a- binding polypeptide, and the use of the CD16a-binding polypeptide or pharmaceutical compositions as a medicament, particularly for use in the treatment or prophylaxis of cancer, such as multiple myeloma.

Description

[0001] Novel polypeptides

[0002] Field of the Invention

[0003] The present invention relates to immune cell-engaging polypeptides comprising at least one CD16a-binding polypeptide and at least one additional binding moiety which is a binding partner recognising an immune checkpoint molecule and which is a polypeptide, peptide or small molecule. The present invention also relates to pharmaceutical compositions comprising said immune cell-engaging polypeptides, and their use in the treatment and / or prophylaxis of cancer.

[0004] Background of the Invention

[0005] Immunotherapy has proven to be an effective treatment of several cancers with approved therapies constituting monoclonal and bispecific antibodies, immunomodulatory drugs and CAR-T treatments. Despite activity of these treatments, however, some patients exhibit very short responses or fail to respond to treatment. Side effects from some immunotherapies can be severe, especially side effects related to an exacerbated cytokine release. Indeed, cytokine release syndrome is one of the most common serious adverse effects of T cell-engaging immunotherapeutic agents (Shimabukuro-Vornhagen A et al. Cytokine release syndrome. J Immunother Cancer. 2018;6(l):56. doi: 10.1186 / s40425-018-0343-9). Many patients will also, eventually, become resistant to available treatments. Thus, despite recent advances, there is still a need for additional treatment options in cancer immunotherapy.

[0006] One apparent obstacle with current treatment modalities is suboptimal distribution to tumorous tissue. Rates of tissue distribution are negatively correlated with molecular size, and so larger molecules such as antibodies have less efficient tumour penetration than smaller ones. Another issue is immune evasion by cancer cells, which often involves inhibitory immune signals in the tumour environment. Examples of such signals include: the production of immunosuppressive cytokines and other molecules, such as TGFP or VEGF; cell-mediated immunosuppression, e.g. via tumour-derived regulatory T cells; modulation of antigen presentation and MHCI expression; or altered expression of other ligands, e.g. increased expression of inhibitory checkpoint ligands (such as Programmed death-ligand 1 (PD-L1) and HLA-E), which reduces tumour cell killing by CD8+ T cells and natural killer (NK) cells (Vinay D et al, Immune evasion in cancer: Mechanistic basis and therapeutic strategies, Seminars in Cancer Biology. 2015:35 (Supplement): SI 85, https: / / doi.Org / 10.1016 / j.semcancer.2015.03.004; Ben-Shmuel A et al, Unleashing Natural Killer Cells in the Tumor Microenvironment - The Next Generation of Immunotherapy? Front Immunol. 2020; 11 :275, doi: 10.3389 / fimmu.2020.00275).

[0007] NK cells are a component of the innate immune system whose functions include cytokine secretion and cell killing via secretion of perforin- and granzyme-containing cytolytic granules. They are capable of antibody-dependent cellular cytotoxicity (ADCC) when target cells, such as tumour cells, are bound by IgG antibodies. Binding of the Fc antibody region to the CD16 receptor (FCyRIII) on NK cells overrides inhibitory signals, triggering cytokine secretion and lysis of the target cell (Vivier E et al, Functions of natural killer cells, Nat Immunol. 2008;9:503, https: / / doi.org / 10.1038 / nil582; Pallmer K and Oxenius A, Recognition and regulation of T cells by NK cells, Front Immunol 2016, 7:251, https: / / doi.org / 10.3389 / fimmu.2016.00251).

[0008] CD 16 is expressed in two forms, CD 16a and CD 16b, which vary in their expression patterns and affinities for IgG Fc. CD 16a is the form predominantly expressed on NK cells, as well as being found on monocytes. CD 16b, in contrast, is mostly found on neutrophils, though its expression can also be induced on eosinophils. Despite the high degree of sequence similarity (around 96%) between CD 16a and CD 16b, CD 16a has a much higher binding affinity for IgG. (Roberts JT and Barb AW, A single amino acid distorts the Fc y receptor IIIb / CD16b structure upon binding immunoglobulin G1 and reduces affinity relative to CD16a, J Biol Chem. 2018;293(51): 19899-19908, doi: 10.1074 / jbc.RAl 18.005273). Genotypic variation of the CD16a (FcyRIIIa) receptor itself can also alter its binding affinity: the FcyRIIIa- 176 V / F polymorphism (rs396991) (in some publications where the leader sequence is excluded, position 176 is reported as position 158 and this numbering is also used in the Examples herein) results in either a valine (V) or phenylalanine (F) at position 176, giving rise to variable binding phenotypes (F / F: low affinity; V / V or V / F: high affinity, and therefore higher NK cell-mediated ADCC). (Chong KT et al., Distribution of the FcyRIIIa 176 F / V polymorphism amongst healthy Chinese, Malays and Asian Indians in Singapore, Br J Clin Pharmacol 2006;63(3): 328-332, doi: 10.1111 / j.1365- 2125.2006.02771.x).

[0009] Recently, there has been increasing interest in harnessing the NK cell response for cancer immunotherapy. These include use of checkpoint inhibitor blockers, the ex vivo expansion and administration of NK cells, production of CAR-NK cells (analogous to CAR-T cell therapies), and the use of bi- or multivalent NK cell engagers that cross-link NK cells to cancer cells expressing specific antigens (Hofer E and Koehl U, Natural Killer Cell-Based Cancer Immunotherapies: From Immune Evasion to Promising Targeted Cellular Therapies, Front Immunol. 2017;8:745, https: / / doi.org / 10.3389 / fimmu.2017.00745).

[0010] Antibody -based NK engagers under development include Affimed’s AFM13 (an anti- CD16a / CD30 tetravalent bispecific antibody) and AFM24 (an anti-CD16a / EGFR IgGi-scFv fusion antibody). Both AFM13 and AFM24 have additionally been tested for their ability to induce tumour cell killing by macrophages via antibody-dependent cellular phagocytosis (ADCP) (Wingert S et al, Preclinical evaluation of AFM24, a novel CD16A-specific innate immune cell engager targeting EGFR-positive tumors. MAbs. 2021;13(l): 1950264. doi: 10.1080 / 19420862.2021.1950264; Wingert S et al, CD16A-Specific Tetraval ent Bispecific Immune Cell Engagers Potently Induce Antibody-Dependent Cellular Phagocytosis (ADCP) on Macrophages, Blood 2018;132(Supplement 1): 1111, https: / / doi.org / 10.1182 / blood-2018-99-118427). Other bi- and multivalent NK engagers include the camelid VHH antibody-derived BiKEs and TriKEs, such as GT Biopharma’s GTB-3650 which contains CD33- and CD16a- targeting regions joined to the costimulatory molecule IL15.

[0011] Multiple myeloma is a hematological malignancy that, despite recent advances in immunotherapy, is still incurable. Several surface proteins enriched on myeloma cells have been identified and served as targets for therapeutic interventions. One such target is BCMA (TNFRSF17), which is highly expressed on myeloma cells but to a lesser extent also expressed on non-malignant cells of the B cell compartment as well as plasmcytoid dendritic cells. Two B-cell stimulating ligands, a proliferation- inducing ligand (APRIL) and B-cell activating factor (BAFF), bind to BCMA and are implicated in autoimmune disorders as well as cancer (Bossen and Schneider (2006) BAFF, APRIL and their receptors: Structure, function and signalling, Seminars in Immunology, doi: 10.1016 / j.smim.2006.04.006; Moreaux et al. (2004) BAFF and APRIL protect myeloma cells from apoptosis induced by interleukin 6 deprivation 15 and dexamethasone, Blood 103 (8): 3148-3157; Samy et al. (2017) Targeting BAFF and APRIL in systemic lupus erythematosus and other antibody-associated diseases, International Reviews of Immunology, 36: 1, 3-19).

[0012] CAR-T cell therapies and antibody -based therapies targeting BCMA have proven efficacious in clinical practice prolonging patient overall survival. Still, not all patients show satisfactory response to treatment and patients eventually relapse in their disease (see, for example, Teoh, P.I., Chng, W.I. CAR T-cell therapy in multiple myeloma: more room for improvement. Blood Cancer I. 11, 84 (2021). https: / / doi.org / 10.1038 / s41408-021-00469-5). An antibody-based bispecific engager targeting both BCMA and the NK cell surface molecule CD 16a, RO7297089, has also been investigated. RO7297089 is a bispecific tetravalent antibody and its properties were described in Kakiuchi-Kiyota et al. (Leukemia (2022) 36: 1006-1014; https: / / doi.org / 10.1038 / s41375-021-01478-w). The findings from a Phase I dose- escalation study of RO7297089 in patients with Relapsed / Refractory Multiple Myeloma (Study registration NCT04434469) were reported by Plesner et al. (Poster Abstract 2755, Session 653, American Society of Hematology (ASH) Conference, 12 December 2021).

[0013] Immune checkpoints are normally responsible for maintaining self-tolerance (i.e. preventing autoimmune reactions) and for modulating the immune response to infections in order to minimise tissue damage. In cancer, however, tumour cells may also co-opt immune checkpoint mechanisms to evade anti-tumour immune responses. The B7 protein family is a family of immune checkpoint proteins, many of which are highly expressed in tumors and contribute to tumour-induced immunosuppression through a negative second signal. Experimental evidence suggests that manipulation of the B7 family affects anti-tumor immunity, and therefore B7 family proteins and their receptors are of interest as targets for tumor immune checkpoint therapy (Xiao et al, S ci Rep 2023, 13: 14311). The B7 family includes the ligand PD-L1 (also known as B7-H1 or CD274). PD-L1 binds to the T-cell Programmed death- 1 receptor (PD-1 / CD279) and is normally expressed by immune cells such as macrophages, activated T cells and B cells, dendritic cells. However, PD-L1 is also highly expressed on plasma cells in multiple myeloma, particularly in refractory multiple myeloma where it is associated with increased proliferation, tumour aggressiveness, and resistance to anti-myeloma therapy.

[0014] Blockade of the PD-1 / PD-L1 checkpoint, for example using binders specific to PD- Ll, is a strategy of interest in cancer immunotherapy. Currently approved anti-PD-Ll agents include monoclonal antibodies such as atezolizumab, durvalumab and avelumab, envafolimab, sugemalimab and adebrelimab (although these are not indicated for the treatment of multiple myeloma). Alternative inhibitors of PD-L1 have also been produced, including small molecules (such as those described in WO 2015 / 034820 Al and W02015 / 160641 A2) and affibody-based ‘Z-variants’ (described in for example WO 2017 / 072280 Al). Several such inhibitors have more recently entered Phase I clinical trials, for example the small molecule CA-170 (Curis, trial no. NCT02812875) and the macrocyclic peptide BMS-986189 (Bristol-Meyer- Squibb, trial no. NCT02739373).

[0015] Another B7 family member of relevance is B7-H3 (also known as CD276). B7-H3 is overexpressed in multiple cancer types compared with normal tissues, and its over expression is associated with aggressive cancer phenotypes (including an increased risk of metastasis and resistance), leading to poor prognosis and higher risk of recurrence. Developments include a phase I trial of radioimmunotherapy using an anti-B7-H3 monoclonal antibody,131I-omburtamab (Modak et al, J Clin Oncol 2020, 38:36, 4283), and early stage preclinical work on affibody-based B7-H3 binders (described in patent application no. US2021 / 0340257 Al and Oroujeni et al, Pharmaceutics 2022 14: 1780, Oroujeni et al, Nuclear Medicine and Biology 2023 124-125: 108384). However, there are as yet no approved therapies targeting B7-H3 on the market.

[0016] Despite this progress, there still remains a need for improved cancer immunotherapeutics that can be delivered more efficiently to the tumour, while retaining the target specificity of antibodies and antibody -based drugs and avoiding potential side-effects such as immunogenicity.

[0017] The present invention seeks to address the afore-mentioned needs.

[0018] Summary of the Invention

[0019] The present invention provides a CD16a-binding polypeptide which comprises at least one motif that binds to CD 16a, wherein said polypeptide comprises the following structure:

[0020] [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion] the CD 16a binding motif being the portion [Helix l]-[Separating portion]-[Helix 2], the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule.

[0021] The compounds of the invention that bind to both CD 16a and to a protein in the B7 family have beneficial properties, demonstrated herein, that make them promising for use in therapy.

[0022] In particular, the invention provides such a CD16a-binding polypeptide, wherein:

[0023] Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, a) X9is A, D, F, H, I, K, L, Q, R, T, V or Y;

[0024] X10 is Q;

[0025] Xu is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y;

[0026] X13 is A, Q, or V;

[0027] X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W, or Y;

[0028] X17 is Q or R;

[0029] Xis is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H;

[0030] X25 is A or H;

[0031] X27 is A, I, K, Q, R, S, T or V;

[0032] X28 is F or Y;

[0033] X31 is I or L;

[0034] X32 is A, E, H, K, L, N, Q or R;

[0035] X33 is K or S; and

[0036] X35 is A, H, I, L, M, R or S; or b) X9 is V; X10 is Q; Xu is M; X13 is Q; X14 is F; X17 is R; Xis is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; X33 is S and X35 is M, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue; or c) X9 is Q; X10 is F; Xn is Y; X13 is R; X14 is D; X17 is D; Xis is L; X24 is E; X25 is D; X27 is K; X28 is W; X31 is Y; X32 is M; X33 is S and X35 is I, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue; or d) X9is F; X10 is W; Xn is I; X13 is E; Xi4is S; X17 is E; Xi8is S; X24is I; X25is Y; X27 is K; X28 is W; X31 is K; X32 is Y; X33 is S and X35 is A, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue.

[0037] The invention also provides such a CD16a-binding polypeptide wherein: i) Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 has the sequence X24X25QX27X28AFX31X32SLX35, wherein: a*) X9 is V; X10 is Q; Xu is M; X13 is Q; X14 is F; X17 is R; Xis is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; and X35 is M; b*) X9 is Q; X10 is F; Xu is Y; X13 is R; X14 is D; X17 is D; Xis is L; X24 is E; X25 is D; X27 is K; X28 is W; X31 is Y; X32 is M; and X35 is I; or c*) X9 is F; X10 is W; Xu is I; X13 is E; X14 is S; X17 is E; Xis is S; X24 is I; X25is Y; X27 is K; X28is W; X31 is K; X32 is Y; and X35 is A; or ii) Helix 1 and Helix 2 are defined as in i), wherein within Helix 1 and Helix 2, at least 1 and no more than 3 of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 3 of residues not labelled as Xnare replaced by an alternative residue.

[0038] The present inventors have surprisingly found that CD16a-binding polypeptides described herein and forming part of the compounds of the invention based on a non- antibody scaffold are effective in engaging NK cells and triggering ADCC-mediated cancer cell killing.

[0039] The invention therefore provides novel CD 16a engagers that show promise as anti- cancer immunotherapeutics.

[0040] The invention further provides a CD16a-binding polypeptide, which consists of a CD16a-binding polypeptide of the invention; and, in addition to the binding moiety which is a binding partner recognising a protein in the B7 family, optionally comprises a further additional binding moiety (for example 1, 2, 3, or more additional binding moiety(ies)).

[0041] The invention further provides a CD16a-binding oligomer, which comprises at least two CD16a-binding motifs as recited for the polypeptides of the invention.

[0042] The present invention further provides a CD16a-binding polypeptide as defined herein, or CD16a-binding oligomer as defined herein, which further comprises an additional functional portion (for example at least one, at least two, or at least three; for example 1, 2, 3, 4 or 5 additional functional portions).

[0043] The invention further provides a CD16a-binding polypeptide which comprises at least one motif that binds to CD 16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix l]-[Separating portion]- [Helix 2], wherein the sequence of the CD-16a-binding motif is selected from SEQ ID NOs 1014 to 1026 and 1044.

[0044] The invention further provides a CD16a-binding polypeptide which comprises at least one motif that binds to CD 16a, wherein said polypeptide comprises the following structure:

[0045] [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix l]-[Separating portion]- [Helix 2], wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID NOs: 1001 to 1013 and 1043.

[0046] Such polypeptides comprising a sequence selected from SEQ ID NOs 1014 to 1026 and 1044 and SEQ ID NOs: 1001 to 1013 or 1043 can form a part of a CD16a-binding oligomer. They may also be a part of a binder comprising one or more additional functional portions as described elsewhere herein.

[0047] The invention further provides:

[0048] - a nucleic acid molecule encoding the CD16a-binding polypeptide or CD 16a- binding oligomer of the invention;

[0049] - an expression vector comprising such a nucleic acid molecule;

[0050] - a host cell comprising such a nucleic acid molecule or vector.

[0051] The invention further provides a method of making the CD16a-binding polypeptide or CD16a-binding oligomer of the invention.

[0052] The invention also provides a pharmaceutical composition comprising a CD 16a- binding polypeptide, CD16a-binding oligomer, CD 16a binder-drug conjugate, nucleic acid molecule or expression vector of the invention. The invention further provides a CD16a-binding polypeptide, CD16a-binding oligomer, CD 16a binder-drug conjugate, nucleic acid molecule, expression vector or pharmaceutical composition of the invention for use in medicine, in particular in the treatment of a cancer.

[0053] The invention also provides the use of a CD16a-binding polypeptide, CD16a-binding oligomer, CD 16a binder-drug conjugate, nucleic acid molecule, expression vector or pharmaceutical composition of the invention for the manufacture of a medicament for the treatment of cancer.

[0054] The invention also provides a method of treating cancer in which the method comprises administering to a patient in need thereof a CD16a-binding polypeptide, CD16a-binding oligomer, CD 16a binder-drug conjugate, nucleic acid molecule, expression vector or pharmaceutical composition of the invention.

[0055] The invention further provides a kit comprising a CD16a-binding polypeptide, CD16a-binding oligomer, CD 16a binder-drug conjugate, nucleic acid molecule, expression vector, pharmaceutical composition of the invention and, optionally, one or more further therapeutic agent(s). Such a kit finds particular use in the treatment and / or prophylaxis of cancer.

[0056] Description of the Drawings

[0057] Figure 1 shows (a) schematic domain construction of the binding polypeptides described in the present disclosure; (b) examples of results from a phage-ELISA experiment used to screen individual clones present in the phage output after selection cycle four. In (b), assay responses to coating antigens (1) HSA, (2) Streptavidin, (3) SLAMF7 and (4) hCD16a Fl 58 were measured and representative results for clones corresponding to CD16a-binding polypeptides A10, H09 and Al l, respectively, are shown.

[0058] Figure 2 shows an SDS-PAGE analysis of the expressed and IMAC -purified Hise- CD16a-binding polypeptide -ABDWT constructs corresponding to SEQ ID 78 (lane 1), SEQ ID 76 (lane 2), and SEQ ID 77 (lane 3). Lane M, marker proteins with molecular masses in kilodaltons. Figure 3 shows sensorgrams obtained after injection of the three purified hCD16a binding variants Hise-AlO-ABDwr [SEQ ID 76], Hise-H09-ABDwT [SEQ ID 78] and His6-Al 1-ABDWT [SEQ ID 77] at concentrations ranging from 5 nM to 2.56 pM over sensor chip flow cell surfaces immobilised with hCD16a F158 or hCD16a V158.

[0059] Figure 4 shows the resulting sensorgrams from the pairwise epitope binding assay using fusion proteins Hise-AlO-ABDwr [SEQ ID 76], His6-H09-ABDwr [SEQ ID 78] and Hise-Al 1-ABDWT [SEQ ID 77] in competitive binding studies to hCD16a F158 and hCD16a V158.

[0060] Figure 5 shows an SDS-PAGE analysis of different expressed and IMAC -purified hCD16a-binding constructs, (a) Hise-AlO-Cys [SEQ ID 79] (Lane 1), Hise-Al 1-Cys [SEQ ID 80] (Lane 2), A10-Al l-His6[SEQ ID 83] (Lane 3), Al l-A10-His6[SEQ ID 84] (Lane 4), His6-A10-Al 1-Cys [SEQ ID 81] (Lane 5) and His6-Al l-A10-Cys [SEQ ID 82] (Lane 6). Larger molecular weight bands visible in lanes 1, 2, 5 and 6 correspond to an expected presence of also dimeric species, held together via a disulfide bond formed between the C-terminal cysteines present in these constructs, (b) Anti-BCMA-AlO-AlO-Hise [SEQ ID 86] (Lane 1). Lane M, marker proteins with molecular masses in kilodaltons.

[0061] Figure 6 shows sensorgrams obtained after injection of hCD16a F158 or hCD16a V158 over immobilised hCD16a monomeric binding variants Hise-AlO-Cys [SEQ ID 79] and Hise-Al 1-Cys [SEQ ID 80] and heterodimeric (bi-paratopic) binding variants Hise-Al 0-Al 1-Cys [SEQ ID 81] and Hise-Al l-A10-Cys [SEQ ID 82], respectively.

[0062] Figure 7 shows sensorgrams obtained after injection of the two purified hCD16a bi- paratopic binding variants A10-A1 l-Hise [SEQ ID 83] and Al 1-AlO-Hise [SEQ ID 84] at concentrations ranging from 0.5 nM to 32 nM over sensor chip flow cell surfaces containing immobilised hCD16a F158 or hCD16a V158, respectively.

[0063] Figure 8 shows sensorgrams obtained from single cycle kinetics experiments performed with a fusion protein of SEQ ID 86 containing the heterodimeric Al 0-Al 0 CD16a-binding polypeptide combination attached to the 1-E6 BCMA binding polypeptide [SEQ ID 86] which was injected at five concentrations ranging from 12 to 1000 nM over sensor chip surfaces containing immobilized hCD16a Fl 58 or hCD16a VI 58 proteins, respectively.

[0064] Figure 9 shows an SDS-PAGE analysis of the purified potential dual engager protein anti-hBCMA-H09-A10-His6 [SEQ ID 85] (Lane 1). Lane M, marker proteins with molecular masses in kilodaltons.

[0065] Figure 10 shows the experimental set-up (a) and resulting sensorgrams (b) obtained after successive injections of the dual engager construct anti-hBCMA-H09-A10-Hise [SEQ ID 85] (injection I) and either hCD16a F158 or V158 (injection III) over a sensor chip surface containing immobilised hBCMA-rabbit Fc (hBCMA-rFc) fusion protein.

[0066] Figure 11 shows relative IFNg secretion in cell media in cocultures of MM. IS and PBMC exposed to dual engagers for 4h. Engagers evaluated were Anti-BCMA-AlO- His6[SEQ ID 88], Anti-BCMA-H09-A10-His6[SEQ ID 85], Anti -BCMA-A10-Al 0- Hise [SEQ ID 86], Anti-BCMA-Al 1-AlO-Hise [SEQ ID 87] and their corresponding non BCMA binding counterparts (null).

[0067] Figure 12 shows CD spectra (from before and after heating) and thermal melting curves for CD16a-binding polypeptides A10, H09 and Al 1 [SEQ ID 1, 74 and 75], all equipped with a C-terminal Hisetag.

[0068] Figure 13 shows sensorgrams obtained after injection of 14 alanine-substituted variants (polypeptide- YY-Hise format), at a common concentration of 200 nM), over a sensor chip surface containing CD 16a (Fl 58) protein.

[0069] Figure 14 shows CD spectra (from before and after heating) for 14 alanine- substituted variants (polypeptide- YY-Hise format) of CD16a-binding polypeptide A10.

[0070] Figure 15a shows thermal melting curves for 14 alanine-substituted variants (polypeptide- YY-Hise format) of CD16a-binding polypeptide A10. Figure 15b shows the results of binding experiments of fusion proteins containing the polypeptide with SEQ ID 1 or one of 13 CD16a-binding polypeptide A10 variants in the form of anti-BCMA-A10*-His6 fusion proteins containing an A10* polypeptide corresponding to SEQ IDs 11, 12, 15, 17, 18, 19, 25, 29, 43, 49, 51, 53 or 33(polypeptide-YY-His6 format) with CD16a F158.

[0071] Figure 15c shows a plot of the respective on-rate (M-l s-1) and off-rate (s-1) kinetic constants for the compounds analysed in Figure 15b.

[0072] Figure 16a shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of elotuzumab.

[0073] Figure 16b shows the enhancement of NK cell mediated cell killing of a BCMA positive MM.1 S cell line. Responses were normalized to the maximal response mediated by a belantamab biosimilar.

[0074] Figure 17a shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of elotuzumab.

[0075] Figure 17b shows the enhancement of NK cell mediated cell killing of a BCMA positive MM.1 S cell line. Responses were normalized to the maximal response mediated by a belantamab biosimilar.

[0076] Figure 18 shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of elotuzumab.

[0077] Figure 19a shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of elotuzumab.

[0078] Figure 19b shows the enhancement of NK cell mediated cell killing of a BCMA positive MM.1 S cell line. Responses were normalized to the maximal response mediated by a belantamab biosimilar. Figure 20a shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of elotuzumab.

[0079] Figure 20b shows the enhancement of NK cell mediated cell killing of a BCMA positive MM.1 S cell line. Responses were normalized to the maximal response mediated by a belantamab biosimilar.

[0080] Figure 21a shows results of a cell killing assay with NK cells and MM. Is cells.

[0081] Figure 21b show results from a 8-hour flow cytometry-based killing assay with NK cells and MM. Is (E:T 5: 1), treated with increasing concentrations of any of three dual engager constructs of the invention.

[0082] Figure 22 illustrates hBCMA target specificity of the dual engager construct with SEQ ID 85 in an in vitro multiple myeloma cell cytotoxicity assay.

[0083] Figure 23a to f show the sequences and binding data for example compounds of the invention.

[0084] Figure 24 a to c show the sequences of binding motifs for compounds of the invention.

[0085] Figure 25a show results from a Jurkat-Lucia™ TCR-hPD-1 reporter assay in the presence or absence of the hPD-Ll positive Raji-APC-hPD-Ll cell line. Responses were normalised to the inhibitory response induced by 6.7 nM hPD-Ll antibody (N298A).

[0086] Figure 25b shows result from a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line. Responses were normalized to the maximal response of 200 nM Elotuzumab.

[0087] Figure 25c shows result from a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the hPD-Ll positive Raji-APC-hPD-Ll cell line. Responses were normalized to the activating response of 6.7 nM hPD-Ll Ab. Figure 26a shows result from Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of the BCMA positive MM. IS cell line (believed to be B7-H3+). Responses were normalized to the maximal response of 200 nM Elotuzumab

[0088] Figure 26b shows result from Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence of the BCMA positive MM. IS cell line (believed to be B7-H3+) with varying concentrations of engagers. Responses were normalized to the maximal response of 200 nM Elotuzumab.

[0089] Figure 27 shows responses in a Jurkat-Lucia™ NFAT-CD16 reporter assay in the presence or absence of hPD-Ll+Raji cells. Responses were normalized to the maximal response of 6.7 nM hPD-Ll Ab.

[0090] Figure 28 shows results of an hPD-Ll binding assay using hPD-Ll-CD16a engagers of the invention (negative control: ‘CL hCD16a affibody lacking a hPD-Ll binding portion).

[0091] Figure 29a and b show the sequences of CD 16a binding polypeptide functional portions of the present invention.

[0092] Figure 30 shows the sequences of CD16a binding motifs (i.e. the [Helix 1]- [Separating portion]-[Helix 2] sequence) of example CD 16a binding polypeptide functional portions of the present invention.

[0093] Figure 31a and b show the sequences of example hBCMA binding polypeptide functional portions of the present invention.

[0094] Figure 32 shows the sequences of hBCMA binding motifs (i.e. the [Helix 1b]- [Separating portion]-[Helix 2b] sequence) of example hBCMA binding polypeptide functional portions of the present invention.

[0095] Figure 33 shows (a) a schematic representation of one CD 16a binding polypeptide functional portion (e.g. A10 - SEQ ID NO: 1) and one additional functional portion (e.g. B7H3 binding moiety, AC12-S179) SEQ ID NO:292: and (b) a schematic representation of dimeric constructs of the invention comprising one CD 16a binding polypeptide (e.g. A10 - SEQ ID NO: 1) and one additional functional portion (B7H3 binding moiety e.g. AC12-S179, - SEQ ID NO:292).

[0096] Figure 34 shows the sequence and structure of the hCD16a x B7H3 dual engager dimeric constructs synthesised in Preparative Example 12 (* indicates that a K residue side chain is modified as shown in the structure to have a linker attached to its side chain).

[0097] Figure 35 shows a flow histogram overlay comparing fluorescence levels of B7H3 staining (thick black curve) to a isotype control (shaded).

[0098] Detailed Description

[0099] The present inventors have found that polypeptides as disclosed herein are effective binders of CD 16a and effectively engage immune cells and that they also engage with a protein in the B7 family. The polypeptides have been found to trigger strong ADCC responses against cancer cells in an in vitro model. Notably, the inventors have found that such anti-cancer responses compare favourably in the model with those obtained using the monoclonal antibody elotuzumab, which is approved for treatment of multiple myeloma. Based on the results described herein, the inventors provide evidence that the anti-cancer responses prompted by the compounds of the invention make them promising for use in treatment of cancer, and in particular treatment of multiple myeloma.

[0100] In its broadest aspect, the invention provides a CD16a-binding polypeptide which comprises at least one motif that binds to CD 16a, wherein said polypeptide comprises the following structure:

[0101] [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion]; the CD16a binding motif being the portion [Helix l]-[Separating portion]-[Helix 2]; the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule. The various elements of the polypeptides of the invention will now be described in further detail:

[0102] Overall structure

[0103] In an embodiment, the polypeptides of the present invention may be based on three- helix scaffolds, sometimes referred to as ‘affibodies’. Affibodies are small (around 6.5 kDa) engineered affinity ligands, based on the Z-domain polypeptide, which is a mutated version of the B-domain in the immunoglobulin-binding region of staphylococcal protein A (Nord K et al., Binding proteins selected from combinatorial libraries of an a-helical bacterial receptor domain, Nature Biotech, 1997: 15:772, doi: 10.1038 / nbt0897-772). In a full length affibody, the C-terminal portion includes [Second separating portion]-[Helix 3]-[C-terminal sequence]. The general structure of an affibody is shown in Figure la.

[0104] The portions of the molecules of the invention referred to as Helix 1 and Helix 2 (and Helix 3, when present) are generally helical in structure. In some rare embodiments, it can be found that the structure established by the sequence with particular residues can be not strictly helical. Such compounds are to be considered within the broadest aspect of the invention. More preferably, the residues in the Helix 1 and Helix 2 portions do result in those structures being helical, in the sense of being alpha-helical.

[0105] WO 2023 / 232911 discloses CD 16a- binding polypeptides (incorporated herein by reference). Such polypeptides may be used as a portion of the compounds according to the present invention.

[0106] Sequences of the polypeptides of the invention

[0107] The sequence of the CD16a-binding polypeptides, in particular the binding motif(s), as disclosed herein may be expressed in terms of their constituent amino acids or in terms of nucleic acid sequences encoding polypeptides having those amino acid sequences. In the context of the present disclosure, the term “amino acid” encompasses any naturally occurring amino acid or unnatural amino acid. The term “unnatural amino acid” as used herein refers to non-proteinogenic (i.e. non-encoded) amino acids, which may either be found in nature or are chemically synthesised (for example citrulline, hydroxyproline, beta-alanine, ornithine, norleucine, 3- nitrotyrosine, pyroglutamic acid, nitroarginine, homoleucine or tert-butylalanine). It includes a, P, y and 5 amino acids. It includes an amino acid in any chiral configuration. The amino acid may, especially, be a naturally occurring a amino acid. The amino acid may, especially, be a naturally occurring L amino acid. The amino acid may, especially, be a naturally occurring L-a amino acid.

[0108] Within a polypeptide chain (for example a CD16a-binding polypeptide as disclosed herein), the amino acids are linked by peptide bonds between the carboxyl group of one amino acid and the amine group of the next amino acid in the chain. An individual amino acid is called a “residue” or “amino acid residue” once it is linked in a polypeptide chain.

[0109] The amino acid sequences herein are shown with the N-terminus to the left, and where sequences are set out across multiple lines, the N-terminus is to the top left. Unless indicated otherwise, the amino acid residues in the sequences are L-amino acids.

[0110] The amino acid sequences listed in the application are shown using standard letter abbreviations for amino acids.

[0111] The specific sequences given herein relate to specific embodiments of the invention.

[0112] The present disclosure also includes derivatives of all the sequences described herein (for example, derivatives of each of the CD16a-binding polypeptide and CD 16a- binding oligomer sequences described here). Derivatives of the sequences described herein are, preferably, derivatives wherein from 1 to 5 (for example 1, 2 or 3 amino acid residues) may be replaced by an alternative residue, for example a different naturally occurring amino acid or a different unnatural amino acid; or a different naturally occurring amino acid excluding methionine or a different unnatural amino acid. Preferably, an unnatural amino acid according to the present invention is one that is isosteric with a naturally occurring amino acid, for example norleucine. In one embodiment, an unnatural amino acid according to the present invention is one selected from norleucine, homoleucine and tert-butylalanine.

[0113] For example, in one embodiment, one or more (for example each) methionine residues of the sequences described herein may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, valine and norleucine; and especially isoleucine and norleucine. For example, from 1 to 5 methionine residues, from 1 to 3 methionine residues (for example 1, 2 or 3 methionine residues), or 1 or 2 methionine residues, or 1 methionine residue, when present, may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, norleucine, homoleucine and tert-butylalanine (for example isoleucine, leucine, glutamine, and norleucine; or norleucine, homoleucine and tert-butylalanine) and especially isoleucine and norleucine.

[0114] For example, in embodiments wherein Xu may be or is methionine, the residue at Xu may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, norleucine, homoleucine and tert-butylalanine (for example isoleucine, leucine, glutamine, and norleucine; or norleucine, homoleucine and tert-butylalanine) and especially isoleucine and norleucine. For example, in embodiments wherein X35 may be or is methionine, the residue at X35 may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, norleucine, homoleucine and tert-butylalanine; and especially isoleucine and norleucine. For example, in embodiments wherein Xu and X35 may be or are methionine, the residues at Xu and X35 may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, norleucine, homoleucine and tert-butylalanine; and especially isoleucine and norleucine. For example, in embodiments wherein X32 may be or is methionine, the residue at X32 may be replaced by a different naturally occurring amino acid or unnatural amino acid, such as an amino acid selected from isoleucine, leucine, glutamine, norleucine, homoleucine and tert-butylalanine; and especially isoleucine and norleucine.

[0115] Alternatively, or additionally, in certain embodiments, the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may contain amino acid substitutions wherein one or more residues is replaced by an unnatural amino acid.

[0116] For example, in one embodiment, one or more residues of the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may be replaced by an unnatural amino acid, for example norleucine, homoleucine or tert-butylalanine. For example, from 1 to 15 residues may be replaced by unnatural amino acid(s), for example from 1 to 10 residues (for example 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 residues), from 1 to 5 residues (for example 1, 2, 3, 4 or 5), from 1 to 3 residues (for example 1, 2, or 3), or 1 residue may be replaced by unnatural amino acid(s) (for example norleucine, homoleucine or tert- butylalanine).

[0117] For example, in one embodiment, one or more leucine residues of the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may be replaced by an unnatural amino acid, and preferably norleucine. For example, from 1 to 5 leucine residues, from 1 to 3 leucine residues (for example 1, 2 or 3 leucine residues), or 1 or 2 leucine residues, or 1 leucine residue, when present, may be replaced by unnatural amino acid (for example norleucine). For example, in certain embodiments, in the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here), at a position at which a leucine residue is recited, the polypeptide has the sequence with the leucine residue independently substituted for an unnatural amino acid, and preferably norleucine.

[0118] Alternatively, or additionally, in one embodiment, one or more methionine residues of the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may be replaced by an unnatural amino acid, for example norleucine, homoleucine or tert-butylalanine, and preferably norleucine. For example, from 1 to 5 methionine residues, from 1 to 3 methionine residues (for example 1, 2 or 3 methionine residues), or 1 or 2 methionine residues, or 1 methionine residue, when present, may be replaced by unnatural amino acid (for example norleucine). For example, in certain embodiments, in the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here), at a position at which a methionine residue is recited, the polypeptide has the sequence with the methionine residue independently substituted for an unnatural amino acid, for example norleucine, homoleucine or tert- butylalanine, and preferably norleucine.

[0119] For example, in embodiments wherein Xu may be or is methionine, the residue at Xu may be replaced by an unnatural amino acid(s) (for example norleucine). For example, in embodiments wherein X35 may be or is methionine, the residue at X35 may be replaced by an unnatural amino acid(s) (for example norleucine). For example, in embodiments wherein Xu and X35 may be or are methionine, the residues at Xu andXss may be replaced by unnatural amino acids (for example norleucine). For example, in embodiments wherein X32 may be or is methionine, the residue at X32 may be replaced by an unnatural amino acid(s) (for example norleucine).

[0120] In certain embodiments, one or more methionine residues of the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may be oxidised, for example in the form of methionine sulfoxide (“Met(O)”). For example, from 1 to 5 methionine residues, from 1 to 3 methionine residues (for example 1, 2 or 3 methionine residues), or 1 or 2 methionine residues, or 1 methionine residue, when present, may be oxidised (for example may be Met(O)). For example, in embodiments wherein Xu may be or is methionine, when present the methionine at Xu may be oxidised (for example Met(O)). For example, in embodiments wherein X35 may be or is methionine, when present the methionine may be oxidised (for example Met(O)). For example, in embodiments wherein Xu and X35 may be or are methionine, when present the methionines at Xu andXss may be oxidised (for example Met(O)). For example, in embodiments wherein X32 may be or is methionine, when present the methionine may be oxidised (for example Met(O))

[0121] Alternatively, or additionally, in certain embodiments, the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) comprise a peptide purification tag or moiety (for example a histidine- tag (for example a polyhistidine tag optionally comprising tyrosine) or a methionine- tag (for example a single methionine tag or a polymethionine tag)), a signalling tag or moiety (for example a glycine residue, or a signal peptide, for example selected from signal peptides of OmpA, DsbA, PhoA, and PelB), a fluorophore tag (for example Alexa448 (AlexaFluor™488) or Alexa647(AlexaFluor™)), or a tag or moiety to assist conjugation, a cysteine tag (for example a single cysteine at the C or N terminal)) or a tag to assist in detection in biological samples (for example an alfa, flag or myc-tag). Such tags and / or moieties may, preferably, be present at the N- terminal and / or the C-terminal of the CD16a-binding polypeptide and CD16a-binding oligomer sequences described herein. In an embodiment, the CD16a-binding polypeptides and CD16a-binding oligomers described herein may comprise one or more of the following: a peptide purification tag or moiety (for example a histidine- tag (for example a polyhistidine tag optionally comprising tyrosine) or a biotin tag; a fluorophore tag (for example Alexa448 (AlexaFluor™488) or Alexa647(AlexaFluor™)); and a tag to assist in detection in biological samples (for example an alfa tag). Such tags and / or moieties may preferably be present at the N- terminal and / or the C-terminal of the CD16a-binding polypeptide and CD16a-binding oligomer sequences described herein

[0122] Therefore, the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise an additional sequence of at least 1 histidine residue (and optionally at least 1 tyrosine residue) and / or at least 1 methionine residue; for example at least 4, at least 5, or at least 6 histidine residues (and optionally at least 1 tyrosine residue, for example 1, 2 or 3 tyrosine residues) and / or at least 1 methionine residue. In one embodiment, the sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise an additional sequence of at least 6 histidine residues and optionally at least 1 tyrosine residue (for example 6 histidine residues (e.g. HHHHHH) or 6 histidine residues and two tyrosine residues (e.g. YYHHHHHH)) and / or at least 1 methionine residue (for example 1 or 2 methionine residues). A peptide purification tag or moiety, for example a histidine-tag or a methionine-tag as described above, may preferably be present at the N-terminal and / or the C-terminal of the CD16a-binding polypeptide and CD16a-binding oligomer sequences described herein. For example, an additional sequence of at least 6 histidine residues (for example 6 histidine residues; or 6 histidine residues and two tyrosine residues) and / or at least 1 methionine residue (for example 1 or 2 methionine residues) may be present at the N- terminal and / or the C-terminal of the CD16a-binding polypeptide and CD16a-binding oligomer sequences described herein.

[0123] The sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise an additional sequence of at least one cysteine (for example one cysteine) at the N- terminal or the C-terminal. The sequences described herein (for example, the CD 16a- binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise a fluorophore tag (for example Alexa448 (AlexaFluor™488) or Alexa647(AlexaFluor™)); at the N-terminal or the C-terminal. The sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise a signal peptide, for example selected from OmpA, DsbA, PhoA, and PelB, athe the N-terminal or the C- terminal, preferably the N-terminal. The sequences described herein (for example, the CD16a-binding polypeptide and CD16a-binding oligomer sequences described here) may further comprise an additional sequence of at least one glycine (for example one glycine) at the N-terminal or the C-terminal.

[0124] In certain embodiments, the CD16a-binding polypeptide is one wherein the CD 16a binding efficacy is at least 1%, at least 5%, or preferably at least 10% (more preferably at least 15%, 20% 25% or 50%) of SEQ ID NO: 1, 74 or 75. When a CD16a-binding polypeptide is described herein as having CD 16a binding efficacy that is at least X% of a specific peptide (e.g. SEQ IS NO: 1, 74 or 75), it is understood that the IC50 concentration of the polypeptide for binding to the CD 16a receptor is no more than 100 / X times the IC50 concentration for the specific peptide (SEQ ID NOs: 1, 74 or 75) to the CD 16a receptor, when measured under the same conditions.

[0125] For example, if the binding efficacy of a CD16a-binding polypeptide is at least 5%, and more preferably at least 10%, 20%, 25% or 50% of the CD 16a binding efficacy of the specific peptide (e.g. SEQ ID NOs: 1, 74 or 75), that is to say that the IC50 concentration of the alternative polypeptide for binding to the CD 16a receptor is no more than 20 times and more preferably 10 times, 5 times, 4 times or 2 times, respectively, the IC50 concentration for the specific peptide (e.g. SEQ ID NOs: 1, 74 or 75) to the CD16a receptor, when measured under the same conditions.

[0126] In certain embodiments, alternatively, or additionally, the CD16a-binding polypeptide is one that competes with SEQ ID NOs: 1, 74 and / or 75.

[0127] The CD16a-binding polypeptides of the present invention have binding affinity for the CD 16a receptor; and may optionally have binding affinity for the CD 16b receptor.

[0128] For example, in certain embodiments the CD16a-binding polypeptides of the present invention have similar binding affinity for the CD 16a receptor and CD 16b receptor; in certain embodiments, the CD16a-binding polypeptides of the present invention have stronger binding affinity for the CD 16a receptor than the CD 16b receptor and in certain embodiments, the CD16a-binding polypeptides of the present invention have stronger binding affinity for the CD 16b receptor than the CD 16a receptor. The CD16a-binding polypeptides of the present invention may have binding affinity to one or both genotypic variation of the CD 16a (FcyRIIIa) receptor: the FcyRIIIa- 176V / F polymorphism (rs396991) (in some publications where the leader sequence is excluded, position 176 is reported as position 158 and this numbering is also used in the Examples herein). Preferably, the CD16a-binding polypeptides of the present invention have binding affinity for both genotypic variation of the CD 16a (FcyRIIIa) receptor: the FcyRIIIa- 176 V / F polymorphism (rs396991). In certain embodiments, the CD16a-binding polypeptides of the present invention have a stronger binding affinity for the valine (V) position 176 phenotype or have a stronger binding affinity for the phenylalanine (F) position 176 phenotype or have similar binding at both the F and the V position 176 phenotype.

[0129] The present invention provides a CD16a-binding polypeptide which comprises at least one motif that binds to CD 16a, wherein said polypeptide comprises the following structure:

[0130] [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion] the CD 16a binding motif being the portion [Helix l]-[Separating portion]- [Helix 2],

[0131] Preferably, Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, a) X9is A, D, F, H, I, K, L, Q, R, T, V or Y;

[0132] X10 is Q;

[0133] Xu is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y;

[0134] X13 is A, Q, or V;

[0135] X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y;

[0136] X17 is Q or R;

[0137] Xis is A, D, E, F, H, I, K, N, Q, R, S, T or V;

[0138] X24is H;

[0139] X25 is A or H;

[0140] X27 is A, I, K, Q, R, S, T or V;

[0141] X28 is F or Y;

[0142] X31 is I or L; X32 is A, E, H, K, L, N, Q or R;

[0143] X33 is K or S; and

[0144] X35 is A, H, I, L, M, R or S; or b) X9 is V; X10 is Q; Xu is M; X13 is Q; X14 is F; X17 is R; Xis is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; X33 is S and X35 is M, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue; or c) X9 is Q; X10 is F; Xn is Y; X13 is R; X14 is D; X17 is D; Xis is L; X24 is E; X25 is D; X27 is K; X28 is W; X31 is Y; X32 is M; X33 is S and X35 is I, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue; or d) X9is F; X10 is W; Xn is I; X13 is E; Xi4is S; X17 is E; Xi8is S; X24is I; X25is Y; X27 is K; X28 is W; X31 is K; X32 is Y; X33 is S and X35 is A, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue.

[0145] In certain embodiments, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xn is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; Xi4is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27 is A, I, K, Q, R, S, T or V; X28is F or Y;X3I is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M R or S. In a further embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, F, H, I, K, L, Q, R, T,

[0146] V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; Xi4is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is H or A; X27 is A, I, K, Q, R, T, S or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M, R or S.

[0147] In a further embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, F, H, I, K, L, Q, R, T,

[0148] V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; Xi4is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R; Xi8is A, D, E, F, H, K, N, Q, R, S, T or V; X24is H; X25is H; X27 is A, I, K, Q, R, T, S or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M, R or S.

[0149] In a further embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, F, H, I, K, L, Q, R, T,

[0150] V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is H or A; X27 is A, I, K, Q, R, T or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

[0151] In a further embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, F, H, I, K, L, Q, R, T,

[0152] V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R; Xi8is A, D, E, F, H, K, N, Q, R, S, T or V; X24is H; X25is H; X27 is A, I, K, Q, R, T, or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S. In certain preferred embodiments, the CD16a-binding polypeptide of the invention has a fast binding or “on” rate for the CD 16a receptor. For example, the CD 16a- binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q;Xn is A, D, E, F, H, I, K, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; Xi4is H, I, K, L, N, Q, R, S, V, W or Y; X17 is R; Xi8is A, D, E, F, H, K, N, Q, R, S or T; X24is H; X25is H; X27 is A, I, K, Q, R, T or V; X28is F; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is H, I, L, R or S.

[0153] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has a slow dissociation rate or “off’ rate for the CD16a receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9is D, F, H, I, K, L, Q, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A or Q; Xi4is H, I, K, L, Q, R, S, T, V, W or Y; X17 is R; Xi8is A, D, E, F, H, K, N, Q, R, S, T or V; X24is H;X25is H; X27 is A, I, K, Q, R, T or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L or R.

[0154] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has a high binding affinity for the CD 16a receptor, for example a Kofor the CD 16a receptor of less than 250 nM. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, F, H, I, K, L, Q, R, T, V or Y X10 is Q; Xu is A, D, E, F, H, I, K, N, Q, R, S, T, V, W or Y; X13 is A or Q; Xi4is H, I, K, L, Q, R, S, V, W or Y; X17 is R; Xi8is A, F, H, K, N, Q, R, S or T; X24is H; X25is H; X27 is A, I, K, Q, R, T or V; X28is F or Y; X31 is I or L; X32 is E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

[0155] In certain preferred embodiments, the CD16a-binding polypeptide of the invention have an especially fast binding or “on” rate for the CD16a receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is F, L, Q, T or Y; X10 is Q; Xu is A, F, H, I, L, N, Q, S, or Y; Xi3is A or Q; Xi4is I, K, Q, R or V; Xi7is R; Xi8is A, E, H, K, Q, R, T or V; X24is H; X25is H; X27is A, I, K, Q, R or V; X28is F; X31 is I; X32is A, H, K, N, Q or R; X33is K or S; and X35is H, I or L.

[0156] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has an especially slow dissociation rate or “off’ rate for the CD16a receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9XioXnAXi3Xi4EIXi7Xi8and Helix 2 comprises the sequence X24X23QX27X28AFX3iX32X33LX35, wherein, X9 is I, L, Q, T or V; X10 is Q; Xu is A, E, F, H, I, S, V or Y; Xi3is Q; Xi4is K, L, R, V, W or Y; Xi7is R; Xi8is A, H, K, Q, R, S or T; X24is H; X25is H; X27is I, K, Q, R, T or V; X28is F; X3iis I or L; X32is K, N or R; X33is K or S; and X35 is I or L.

[0157] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has an especially high binding affinity for the CD 16a receptor, for example a Kofor the CD 16a receptor of less than 100 nM. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9XIOXHAXI3XI4EIXI7XI8and Helix 2 comprises the sequence X24X2sQX27X28AFX3iX32X33LX35, wherein, X9 is I, L, Q or V; X10 is Q; Xu is A, E, H, I, S, W or Y; Xi3is Q; Xi4is K, L, R, V, W or Y; Xi7is R; Xi8is A, H, K, Q, R, S, or T; X24is H; X25is H; X27is K, Q, R, T or V; X28is F; X3iis I; X32is K, N or R; X33is K or S; and X33is I or L.

[0158] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has at least two of the following: a fast binding or “on” rate for the CD 16a receptor; and / or a slow dissociation rate or “off’ rate for the CD 16a receptor; and / or a high binding affinity for the CD 16a receptor, for example a Kofor the CD 16a receptor of less than 100 nM. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9XIOXHAXI3XI4EIXI7XI8and Helix 2 comprises the sequence X24X2sQX27X28AFX3iX32X33LX3s, wherein, X9 is I, L, Q or V; X10 is Q; Xu is A, E, H, I, S or Y; Xi3is Q; Xi4is K, L, R, V, W or Y; Xi7is R; Xi8is H, K, Q, R, S or T; X24is H;X25is H; X27is K, Q, R, T or V; X28is F; X3iis I; X32is N or K; X33is K or S; and X33is I or L. In certain preferred embodiments, the CD16a-binding polypeptide of the invention has an especially slow dissociation rate or “off’ rate for the CD 16a receptor and has a high binding affinity for the CD 16a receptor, for example a Kofor the CD 16a receptor of less than 100 nM. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L or V; X10 is Q; Xu is A, I, S or Y; X13 is Q; Xi4is K, R or V; X17 is R; Xi8is K, Q, R, S or T; X24is H; X25 is H; X27 is K, R or V; X28 is F; X31 is I; X32 is N or K; X33 is K or S; and X35 is I or L.

[0159] In certain preferred embodiments, the CD16a-binding polypeptide of the invention binds the CD 16a and CD 16b receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is D, H, I, K, L, Q, T or V; X10 is Q; Xu is A, D, E, F, H, I, K, N, R, S, V, W or Y; X13 is Q; Xi4is K, L, Q, R, S, V, W or Y; X17 is R; Xi8is A, H, K, N, Q, R, S or T; X24is H; X25is H; X27 is A, I, K, Q, R, T or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is A, I, L, or R.

[0160] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has a binding preference for the CD 16a receptor compared to the CD 16b receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is K, Q or Y; X10 is Q; Xu is I or Q; X13 is Q; X14 is W or Y; X17 is R; Xi8is H, K or R; X24is H; X25is H; X27 is A, K or T; X28 is F; X31 is I; X32 is A, K or Q; Xss is K or S; and X35 is I or L;

[0161] In certain preferred embodiments, the CD16a-binding polypeptide of the invention has a binding preference for the CD 16b receptor compared to the CD 16a receptor. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, V or Y; X10 is Q; Xu is I, N or Q; X13 is Q; X14 is K, R or Q; X17 is R; Xis is E, A or V; X24 is H; X25 is H; X27 is K or Q; X28 is F; X31 is I; X32 is H, K or Q; X33 is K or S; and X35 is I or L In certain very preferred embodiments, the CD16a-binding polypeptide of the invention, is especially active in functional assays, e.g. a CD 16 reporter assay and / or a cell killing assay. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, Q, T or V; X10 is Q; Xu is I, V or Y; X13 is Q; Xi4is K, R or Y; X17 is R; Xi8is K, R, S or T; X24is H; X25is H; X27 is I, T or V; X28 is F; X31 is I or L; X32 is K or N; X33 is K or S; and X35 is I or L.

[0162] In certain especially preferred embodiments, the CD16a-binding polypeptide of the invention, is very especially active in functional assays, e.g. a CD 16 reporter assay and / or a cell killing assay. For example. For example, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, T or V; X10 is Q; Xu is I, V or Y; X13 is Q;Xu is K or R; X17 is R; Xis is R, S or T; X24 is H; X25 is H; X27 is I or V; X28 is F; X31 is I or L; X32 is K or N; Xss is K; and X35 is I or L.

[0163] In certain embodiments, the CD16a-binding polypeptide of the invention is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, Q or V; X10 is Q; Xu is H, I, M, N or Y (preferably H, I, N or Y); X13 is Q; Xi4is F, K, R or Y; X17 is R; Xi8is A, K, Q, R or S; X24is H; X25is H; X27 is Q, S, T or V; X28is F; X31 is I; X32 is A, H, K or N; X33 is K or S; and X35 is I, L or M.

[0164] In another embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, Q or V; X10 is Q; Xu is I, M, N or Y (preferably I, N or Y); X13 is Q; X14 is F, K, R or Y; X17 is R; Xis is A, K, R or S; X24is H; X25is H; X27 is Q, S, T or V; X28is F; X31 is I; X32 is H, K or N; X33 is K or S; and X35 is I, L or M. In another embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, Q or V; X10 is Q; Xu is I, M, N or Y (preferably I, N or Y); X13 is Q; Xi4is F, K, R or Y; X17 is R; Xi8is R; X24is H; X25is H; X27 is Q, S, T or V; X28is F; X31 is I; X32 is H, K or N; X33 is K or S; and X35 is I, L or M.

[0165] In another embodiment, the CD16a-binding polypeptide is one wherein Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein, X9 is L, Q or V; X10 is Q; Xu is I, M or N (preferably I or N); X13 is Q; X14 is F, R or Y; X17 is R; Xis is A, K or R; X24is H; X25is H; X27 is Q, S, or T; X28is F; X31 is I; X32 is H or K; X33 is K or S; and X35 is I, L or M.

[0166] In certain embodiments of the present invention, the CD16a-binding polypeptide is one that has a R at position Xis.

[0167] In certain embodiments of the present invention, the CD16a-binding polypeptide is one that does not have a methionine residue at position Xu or at X35, for example a CD16a-binding polypeptide wherein:

[0168] Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein:

[0169] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y or an unnatural amino acid (for example norleucine); X13 is A, Q, or V; X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27 is A, I, K, Q, R, S, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R, S or an unnatural amino acid (for example norleucine); or

[0170] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W, Y, isoleucine, leucine, glutamine, or norleucine (for example A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W, Y, isoleucine or norleucine); X13 is A, Q, or V; X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W, or Y; X17 is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27is A, I, K, Q, R, S, T, or V; X28is F or Y; X31 is I or L; X32is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R, S, isoleucine, leucine, glutamine, or norleucine (for example, A, H, I, L, R, S, isoleucine or norleucine ); or

[0171] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A, Q, or V; Xi4is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27is A, I, K, Q, R, S, T or V; X28is F or Y; X31 is I or L; X32is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

[0172] In a further embodiment, that does not have a methionine residue at position Xu or at X35, a CD16a-binding polypeptide the CD16a-binding polypeptide is one wherein: Helix 1 comprises the sequence X9XioXnAXi3Xi4EIXi7Xi8and Helix 2 comprises the sequence X24X25QX27X28AFX3iX32X33LX35, wherein,

[0173] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W Y or an unnatural amino acid (for example norleucine); X13 is A, Q or V; Xi4is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; Xi7is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27is A, I, K, Q, R, S, T, or V; X28is F or Y; X31 is I or L; X32is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R, S or an unnatural amino acid (for example norleucine); or

[0174] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W, Y, isoleucine, leucine, glutamine, or norleucine (for example A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W, Y, isoleucine or norleucine); X13 is A, Q or V; Xi4is A, F, H, I, K, L, N, Q, R, S, T, V, W, or Y; Xi7is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27is A, I, K, Q, R, S, , or V; X28is F or Y; X31 is I or L; X32is A, E, H, K, L, N, Q, or R; X33 is K or S; and X35 is A, H, I, L, R, S, isoleucine, leucine, glutamine, or norleucine (for example, A, H, I, L, R, S, isoleucine or norleucine); or

[0175] X9is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; Xi4is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; Xi7is Q or R; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is A or H; X27 is A, I, K, Q, R, S, T or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

[0176] In a further embodiment, that does not have a methionine residue at position Xu or at X35, a CD16a-binding polypeptide the CD16a-binding polypeptide is one wherein:

[0177] Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, wherein,

[0178] X9is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W, Y or an unnatural amino acid (for example norleucine); X13 is A, Q or V; X14 is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is H or A; X27 is A, I, K, Q, R, T, S or V; X28is F or Y;X3I is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R, S or an unnatural amino acid (for example norleucine) ; or

[0179] X9is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W Y, isoleucine, leucine, glutamine, or norleucine (for example A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W Y, isoleucine or norleucine); X13 is A, Q or V; X14 is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; Xi8is A, D, E, F, H, I, K, N,

[0180] Q, R, S, T or V; X24is H; X25is H or A; X27 is A, I, K, Q, R, T, S or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R S, isoleucine, leucine, glutamine, or norleucine (for example A, H, I, L, R, S, isoleucine or norleucine); or

[0181] X9is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; Xu is A, D, E, F, H, I, K, L, N, Q,

[0182] R, S, T, V, W or Y; X13 is A, Q or V; Xi4is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; Xi8is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24is H; X25is H or A; X27 is A, I, K, Q, R, T, S or V; X28is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

[0183] In certain embodiments, the CD16a-binding polypeptide is one wherein the CD 16a binding efficacy is at least 1%, at least 5%, or preferably at least 10% (more preferably at least 15%, 20% 25% or 50%) of SEQ ID NO: 1 (i.e. binding efficacy of the peptide of SEQ ID NO: 1 to the CD 16a receptor, when measured under the same conditions). Preferably, the CD16a-binding polypeptide is one wherein the CD 16a binding efficacy is at least 10% of SEQ ID NO: 1.

[0184] In certain embodiments, alternatively, or additionally, the CD16a-binding polypeptide is one that competes with SEQ ID NO: 1.

[0185] In advantageous embodiments of CD16a-binding polypeptides of the invention, Proline (P) and Cysteine (C) are not present in Helix 1 or Helix 2 of a CD 16a binding polypeptide of the present invention. Advantageously Glycine (G) is also not present in Helix 1 or Helix 2 of a CD 16a binding polypeptide of the present invention.

[0186] In certain embodiments, a CD16a-binding polypeptide of the invention is one wherein:

[0187] Helix 1 comprises the sequence X6X7X8X9X10X11AX13X14EIX17X18X19 and / or Helix 2 comprises the sequence X23X24X25QX27X28AFX31X32X33LX35X36X37, wherein, Xe is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent (for example Xe is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N)); X?is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent (for example X?is any naturally occurring amino acid (preferably H, K or R; more preferably K)); Xs is any naturally occurring amino acid (preferably D, E, N or Q; more preferably E) or is absent (for example Xs is any naturally occurring amino acid (preferably D, E, N or Q; more preferably E)); X19 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L) or is absent (for example X19 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L)); X23 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent (for example X23 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N); Xseis any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent (for example Xseis any naturally occurring amino acid (preferably D, E, N or Q; more preferably D)); and X37 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent (for example X37 is naturally occurring amino acid (preferably D, E, N or Q; more preferably D)).

[0188] In certain embodiments, a CD16a-binding polypeptide of the invention is one wherein: Helix 1 comprises the sequence X6X7X8X9X10X11AX13X14EIX17X18X19 and / or Helix 2 comprises the sequence X23X24X25QX27X28AFX31X32X33LX35X36X37, wherein, Xe is D, E, N or Q (more preferably N) or is absent (for example Xe is D, E, N or Q, and more preferably N); X7 is H, K or R (preferably K) or is absent (for example X?is H, K or R; and more preferably K); Xs is D, E, N or Q (preferably E) or is absent (for example Xs is D, E, N or Q; and more preferably E); X19 is G, A, V, L or I (preferably L) or is absent (for example X19 is G, A, V, L or I; and more preferably L); X23 is D, E, N or Q (preferably N) or is absent (for example X23 is D, E, N or Q; and more preferably N); X36 is D, E, N or Q more preferably D) or is absent (for example XseisD, E, N or Q; and more preferably D); and X37 is D, E, N or Q (preferably D) or is absent (for example X37 is D, E, N or Q; and more preferably D).

[0189] In certain embodiments of the present invention, such as the embodiments described above:

[0190] Helix 1 comprises the sequence X6X7X8X9X10X11AX13X14EIX17X18X19 and / or Helix 2 comprises the sequence X23X24X25QX27X28AFX31X32 X33LX35X36X37.

[0191] In such embodiments, Xe may be any naturally occurring amino acid or is absent; X7 may be any naturally occurring amino acid or is absent; Xs may be any naturally occurring amino acid or is absent; X19 may be any naturally occurring amino acid or is absent; X23 may be any naturally occurring amino acid or is absent; Xsemay be any naturally occurring amino acid or is absent; and X37 may be any naturally occurring amino or is absent.

[0192] More preferably, Xe may be any naturally occurring amino acid; X7 may be any naturally occurring amino acid; Xs may be any naturally occurring amino acid; X19 may be any naturally occurring amino acid; X23 may be any naturally occurring amino acid; X36 may be any naturally occurring amino acid; and X37 may be any naturally occurring amino.

[0193] In another preferred embodiment, Xe may be D, E, N, Q or is absent; X7 may be H, K, R or is absent; Xs may be any D, E, N, Q or is absent; X19 may be G, A, V, L, I or is absent; X23 may G, A, V, L, I or is absent; X36 may be G, A, V, L, I or is absent; and X37 may G, A, V, L, I or is absent. More preferably, Xs may be E or is absent; X19 may be L or is absent; X23 may be D or is absent; X36 may be D or is absent; and X37 may be D or is absent.

[0194] In an even more preferred embodiment, Xe may be D, E, N or Q; X7 may be H, K or R; Xs may be any D, E, N or Q; X19 may be G, A, V, L or I; X23 may G, A, V, L, or I; X36 may be G, A, V, L or I; and X37 may G, A, V, L or I.

[0195] In another preferred embodiment, Xe may be N or is absent; X7 may be K or is absent; Xs may be E or is absent; X19 may be L or is absent; X23 may be D or is absent; X36 may be D or is absent; and X37 may be D or is absent.

[0196] In an especially preferred embodiment, Xe is N; X?is K; and Xs is E. In another especially preferred embodiment, Xseis D; and X37 is D.

[0197] In a very especially preferred embodiment, Xe is N; X7 is K; Xs is E; X19 is L; X23 is D; X36 is D; and X37 is D. In such embodiments,

[0198] Helix 1 comprises the sequence NKEX9X10X11AX13X14EIX17X18L and / or Helix 2 comprises the sequence DX24X25QX27X28AFX31X32 X33LX35DD.

[0199] In one embodiment, the CD16a-binding polypeptide is one wherein:

[0200] Helix 1 comprises the sequence NKEVQMAQFEIRKL and Helix 2 comprises the sequence NHHQSFAFIKSLMDD; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example, at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

[0201] In certain embodiments, such a CD16a-binding polypeptide has a CD 16a binding efficacy of at least 1%, at least 5%, or at least 10% (for example at least 15%, 20% 25% or 50%) of SEQ ID NO: 1. Preferably, such a CD16a-binding polypeptide has a CD16a binding efficacy that is at least 10% of SEQ ID NO: 1. In certain embodiments, alternatively, or additionally, such a CD16a-binding polypeptide is one that competes with SEQ ID NO: 1.

[0202] In one embodiment, the CD16a-binding polypeptide is one wherein: Helix 1 comprises the sequence NKEQFYARDEIDLL and Helix 2 comprises the sequence NEDQKWAFYMSLIDD; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example, at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

[0203] In certain embodiments, such a CD16a-binding polypeptide has a CD 16a binding efficacy of at least 1%, at least 5%, or at least 10% (for example at least 15%, 20% 25% or 50%) of SEQ ID NO: 74. Preferably, such a CD16a-binding polypeptide has a CD16a binding efficacy that is at least 10% of SEQ ID NO: 74. In certain embodiments, alternatively, or additionally, such a CD16a-binding polypeptide is one that competes with SEQ ID NO: 74.

[0204] In one embodiment, the CD16a-binding polypeptide is one wherein:

[0205] Helix 1 comprises the sequence NKEFWIAESEIESL and Helix 2 comprises the sequence NIYQKWAFKYSLADD; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example, at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

[0206] In certain embodiments, such a CD16a-binding polypeptide has a CD 16a binding efficacy of at least 1%, at least 5%, or at least 10% (for example at least 15%, 20% 25% or 50%) of SEQ ID NO: 75. Preferably, such a CD16a-binding polypeptide has a CD16a binding efficacy that is at least 10% of SEQ ID NO: 75. In certain embodiments, alternatively, or additionally, such a CD16a-binding polypeptide is one that competes with SEQ ID NO: 75.

[0207] In one embodiment, the CD 16a binding motif, being the portion [Helix l]-[Separating portion]-[Helix 2], is (i.e. has a sequence):

[0208] X6X7X8X9X10X11AX13X14EIX17X18X19 X20X21X22X23X24X25QX27X28AFX31X32 X33LX35X36X37 wherein

[0209] X2o is any naturally occurring amino acid, X21 is any naturally occurring amino acid; and X22 is any naturally occurring amino acid, and wherein optionally one or two (for example, optionally 1) of X20, X21 or X22 are absent; and the other residues are as defined above.

[0210] More preferably, Xe may be D, E, N, Q or is absent; X7 may be H, K, R or is absent; Xs may be any D, E, N, Q or is absent; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X19 may be G, A, V, L, I or is absent; X20 may be S, T, M, P, F, Y or W (for example P or T); X21 may be D, E, N or Q; X22 may be G, A, V, L, I or is absent; X23 may G, A, V, L, I or is absent; X36 may be G, A, V, L, I or is absent; and X37 may G, A, V, L, I or is absent; and wherein optionally one or two (for example optionally 1) of X20 , X21 , X22 are absent.

[0211] Preferably, Xe may be D, E, N or Q; X7 may be H, K or R; Xs may be any D, E, N or Q; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X19 may be G, A, V, L or I; X20 may S, T, M, P, F, Y or W (for example P or T); X21 may be D, E, N or Q; and X22 may be G, A, V, L, or I; X23 may G, A, V, L or I; X36 may be G, A, V, L or I; and X37 may G, A, V, L or I; and wherein optionally one or two (for example optionally 1) of X20 , X21, X22 are absent.

[0212] For example, Xe may be D, E, N or Q; X7 may be H, K or R; Xs may be any D, E, N or Q; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X19 may be G, A, V, L or I; X20 may be S, T, M, P, F, Y or W (for example P or T); X21 may be D, E, N or Q; and X22 may be G, A, V, L, or I; X23 may G, A, V, L or I; X36 may be G, A, V, L or I; and X37 may G, A, V, L or I.

[0213] More preferably, Xs may be E or is absent; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X19 may be L or is absent; X23 may be D or is absent; X24, X25, X27, X28, X31, X32, X33 and X35 are as defined above, and X36 may be D or is absent; and X37 may be D or is absent.

[0214] In an especially preferred embodiment, Xe is N; X?is K; Xs is E; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X^is L; X2ois S, T, M, P, F, Y or W (for example P or T), X21 is D, E, N or Q (for example N); and X22 is G, A, V, L or, I (for example L); X23 is D; X36 is D; and X37 is D. Even more preferably, Xe is N; X7 is K; Xs is E; X9, X10, Xu, X13, X14, X17 and Xis are as defined above; X19 is L; X20 is P or T; X2iisN; andX22isL; X23isD; XseisD; and X37 is D.

[0215] For example, the CD16a binding motif is selected from the group consisting of SEQ

[0216] ID Nos: 150 to 221, as shown in Figure 24, and 1014 to 1026 and 1044 (as shown in Figure 30).

[0217] For example, the CD16a binding motif is selected from the group consisting of

[0218] Or is selected from the group consisting of

[0219] In one embodiment, the CD16a binding motif is selected from the group consisting of:

[0220] In one embodiment, the CD16a binding motif is selected from the group consisting of:

[0221] In one embodiment, the CD16a binding motif is selected from the group consisting of: In a polypeptide of Figure 24, Figure 30 and the tables above, the N-terminus of Helix 1 may further comprise the sequence XeXyXs; wherein Xe, X7 and Xs are as defined above, and preferably are NKE (i.e. Xe is N; X7 is K; Xs is E). In a polypeptide of Figure 24, Figure 30 and the tables above, the C-terminus of Helix 2 may further comprise the sequence X36X37; wherein X36 and X3?are as defined above, and preferably are DD i.e. X36 is D; and X37 is D).

[0222] In a polypeptide of Figure 24, Figure 30 and the tables above, optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue. Preferably, in embodiments wherein optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue, the replacement residue is a conservative replacement.

[0223] In a preferred embodiment, the sequence is the one of SEQ ID Nos: 166, 168, 178, 182, 184, 202 or 1014 (i.e. as found in one of Example Compounds 17, 19, 29, 33, 35, 53 and P3 / P4) (and optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue, the replacement residue is a conservative replacement).

[0224] In another preferred embodiment, the sequence is the one of SEQ ID Nos: 164, 166, 168, 184, 200 or 1014, or SEQ ID Nos: 164, 166, 168, 184 or 1014 (i.e. as found in one of Example Compounds 15, 17, 19, 35, 51, P3 / P4 or as found in one of Example Compounds 15, 17, 19, 35, P3 / P4) (and optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue, the replacement residue is a conservative replacement).

[0225] In another preferred embodiment, the sequence is the one of SEQ ID Nos 150, 184 or 200 (and optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue, the replacement residue is a conservative replacement).

[0226] In another preferred embodiment, the sequence is the one of SEQ ID No: 166, 168, 200, or 1014 (and optionally from 1 to 5 residues (for example 1, 2, 3, 4 or 5), preferably 1, 2 or 3 residues, in the sequence are replaced by an alternative residue, the replacement residue is a conservative replacement). In preferred embodiments, the motif sequence additionally has the residues NKE at positions XeXyXs (i.e. Xe is N; X7 is K; Xs is E). In preferred embodiments, the motif sequence additionally has the residues DD at its positions X36X37 (i.e. X36 is D; and X37 is D). For example, the motif sequences have NKE at positions XeX?Xs and DD at positions X36X37 (i.e. Xe is N; X7 is K; Xs is E; X36 is D; and X37 is D). Therefore, in preferred embodiments, the motif sequence may be selected from:

[0227] NKEX9X10X11AX13X14EIX17X18X19 X20X21X22X23X24X25QX27X28AFX31X32 X33LX35X36X37;

[0228] X6X7X8X9X10X11AX13X14EIX17X18X19 X20X21X22X23X24X25QX27X28AFX31X32 X33LX35DD; and

[0229] NKEX9X10X11AX13X14EIX17X18X19 X20X21X22X23X24X25QX27X28AFX31X32 X33LX35DD.

[0230] As mentioned above, in embodiments of the invention a number of residues may each be substituted by an alternative residue, as described herein. For example, in the embodiments described above, even when not explicitly mentioned, optionally 1 to 5 (for example 1, 2, 3, 4 or 5), and preferably optionally 1 to 3 (for example 1, 2, or 3), residues in the sequence of Helix 1 and / or Helix 2 defined above are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement). In any such alternative polypeptides of the invention with alternative residues in place, binding to the CD16a receptor is maintained. For example, the CD16a binding efficacy is at least 1% of the binding efficacy of the peptide of SEQ ID NO: 1 (i.e. binding efficacy of the peptide of SEQ ID NO: 1 to the CD 16a receptor, when measured under the same conditions (as described above)). Alternatively, or additionally, for example, in any such alternative polypeptides of the invention with alternative residues in place, the CD16a-binding polypeptide is one that competes with SEQ ID NO: 1.

[0231] In certain preferred embodiments, the binding efficacy is at least 5%, and more preferably at least 10%, 20%, 25% or 50% of the binding efficacy of the peptide of SEQ ID NO: 1 (i.e. binding efficacy of the peptide of SEQ ID NO: 1 to the CD16a receptor, when measured under the same conditions).

[0232] In advantageous embodiments of CD16a-binding polypeptides of the invention, Proline (P) and Cysteine (C) are not present in CD 16a binding motif of a CD 16a binding polypeptide of the present invention. Advantageously Glycine (G) is also not present in the CD 16a binding motif of a CD 16a binding polypeptide of the present invention.

[0233] In certain embodiments of the invention, the CD16a-binding polypeptide is one wherein: i) Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 has the sequence X24X25QX27X28AFX31X32SLX35, wherein, a*) X9 is V; X10 is Q; Xu is M; X13 is Q; X14 is F; X17 is R; Xis is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; and X35 is M; b*) X9 is Q; X10 is F; Xu is Y; X13 is R; X14 is D; X17 is D; Xis is L; X24 is E; X25 is D; X27 is K; X28 is W; X31 is Y; X32 is M; and X35 is I; or c*) X9 is F; X10 is W; Xu is I; X13 is E; X14 is S; X17 is E; Xis is S; X24 is I; X25is Y; X27 is K; X28is W; X31 is K; X32 is Y; and X35 is A; or ii) Helix 1 and Helix 2 are defined as in i), wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example, at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example, at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue.

[0234] In another embodiment, a*) X9 is V; X10 is Q; Xn is I or norleucine; X13 is Q; X14 is F; X17 is R; Xis is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; and X35 is I or norleucine;

[0235] In an embodiment, Helix 1 comprises the sequence KEX9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32SLX35D, for example Helix 1 comprises the sequence NKEX9X10X11AX13X14EIX17X18L and Helix 2 comprises the sequence NX24X25QX27X28AFX31X32SLX35DD.

[0236] As mentioned above, full identity with the sequences set out for (i) is not required (though in one preferred embodiment of the invention, the peptide does have the exact recited sequence). Of the residues denoted with an Xnlabel, in certain embodiments, at least 1 and no more than 8 of the residues may be replaced with an alternative residue. The replaced residues may be in Helix 1 or in Helix 2, or there may be 1 or more replaced residues in each of Helix 1 and Helix 2 (for example, there may be replaced residue in one of them and 1 or 2 replaced residues in the other). For example, there may be 1, 2, 3, 4, 5, 6, 7 or 8 (for example 1, 2, 3, 4 or 5, or 1, 2 or 3) replaced residues in the residues denoted with an Xnlabel, for example 1, 2, 3, 4 or 5, for example 1 or 2, or 1. As there are 15 residues with an Xnlabel, a peptide with 5 residues replaced has 67% sequence identity with the recited sequence. For replacement of 3 residues, it is 80% and for replacement of 1 residue it is 93% sequence identity. For replacement of 2 residues, it is 87% and for replacement of 1 residue it is 93% sequence identity. In an embodiment in which there are 14 residues with an Xnlabel, a peptide with 5 residues replaced has 64% sequence identity with the recited sequence. For replacement of 3 residues, it is 79% and for replacement of 1 residue it is 93% sequence identity. For replacement of 2 residues, it is 86% and for replacement of 1 residue it is 93% sequence identity.

[0237] Of the residues not labelled as an Xnresidue, at least 1 and no more than 5 of the residues may be replaced with an alternative residue. Preferably, at least 1 and no more than 3 of the residues may be replaced with an alternative residue. The replaced residues may be in either Helix 1 or in Helix 2, or there may be 1 or more replaced residues in each of Helix 1 and Helix 2 (for example there may be replaced residue in one of them and 1 or 2 replaced residues in the other). For example, there may be 1, 2 or 3 replaced residues in the residues not denoted with an Xnlabel, particularly 1 or 2, for example 1. As there are 8 residues without an Xnlabel, a peptide with 3 residues replaced has 63% sequence identity with the recited sequence. For replacement of 2 residues, it is 75% and for replacement of 1 residue it is 88% sequence identity.

[0238] In an embodiment, the total number of residues in the Helix 1 and Helix 2 portions that are replaced is at least 1 and no more than 11, (for example no more than 10, for example no more than 9, for example no more than 8, for example no more than 7), for example at least 1 and no more than 6, for example at least 1 and no more than 5, at least 1 and no more than 4, for example at least 1 and no more than 3, for example 1 at least 1 and no more than 2. Particularly, there may be 1, 2, 3, 4, 5 or 6 replacement residues in total in those portions.

[0239] For example, an amino acid residue replacement for a residue denoted as Xnor a residue not denoted as Xnmay be a conservative replacement. That is to say that a residue is replaced with another residue in the same class, for example: An aliphatic residue (Glycine (G), Alanine (A), Valine (V), Leucine (L) or Isoleucine (I)) may be replaced with another aliphatic residue. A hydroxyl-, sulphur- or selenium-containing residue (Serine (S), Cysteine (C), Selenocysteine (U), Threonine (T) or Methionine (M)) may be replaced with another hydroxyl-, sulphur- or selenium-containing residue. An aromatic residue (Phenylalanine (F), Tyrosine (Y) or Tryptophan (W)) may be replaced with another aromatic residue. A basic residue (Histidine (H), Lysine (K), Arginine (R)) may be replaced with another basic residue. An acidic residue or amide (Aspartate (D), Glutamate (E), Asparagine (N), Glutamine (Q)) may be replaced with another acidic residue or amide.

[0240] Alternatively, an amino acid residue replacement for a residue denoted as Xnor a residue not denoted as Xnmay be a non-conservative replacement, i.e. a residue is replaced with another residue in a different class, for example an aliphatic residue (Glycine (G), Alanine (A), Valine (V), Leucine (L) or Isoleucine (I)) may be replaced with an aromatic residue (Phenylalanine (F), Tyrosine (Y) or Tryptophan (W)), or for example replaced by an amino acid with opposite characteristics, for example replacement of a Lysine (K) residue with an Aspartic acid (D) residue.

[0241] In one embodiment, the CD16a-binding polypeptide is one wherein: a*) Helix 1 comprises the sequence VQMAQFEIRK (SEQ ID No: 230) and Helix 2 comprises the sequence HHQSFAFIKSLM (SEQ ID No: 231). For example, Helix 1 comprises the sequence NKEVQMAQFEIRKL (SEQ ID No: 232) and Helix 2 comprises the sequence NHHQSFAFIKSLMDD (SEQ ID No: 233).

[0242] In such embodiments, optionally at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement);

[0243] In a further embodiment, the CD16a-binding polypeptide is one wherein: b*) Helix 1 comprises the sequence QFYARDEIDL (SEQ ID No: 234) and Helix 2 comprises the sequence EDQKWAFYMSLI (SEQ ID No: 235). For example, Helix 1 comprises the sequence NKEQFYARDEIDLL (SEQ ID No: 236) and Helix 2 comprises the sequence NEDQKWAFYMSLIDD (SEQ ID No: 237). In such embodiments, optionally at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement);

[0244] In a further embodiment, the CD16a-binding polypeptide is one wherein: c*) Helix 1 comprises the sequence FWIAESEIES (SEQ ID No 238) and Helix 2 comprises the sequence IYQKWAFKYSLA (SEQ ID No 239). For example, Helix 1 comprises the sequence NKEFWIAESEIESL(SEQ ID No 240) and Helix 2 comprises the sequence NIYQKWAFKYSLADD (SEQ ID No 241).

[0245] In such embodiments, optionally at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5; or for example at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example, replaced by an alternative residue that is a conservative replacement);

[0246] As discussed above, a number of residues may each be substituted by an alternative residue.

[0247] The CD16a-binding polypeptide of the invention has the overall structure [N-terminal portion]-[Helix l]-[Separating portion]-[Helix 2]-[C-terminal portion].

[0248] The separating portion may be a sequence of from 1 to 5 (for example 1, 2, 3, 4 or 5) naturally occurring amino acids. Preferably, the separating portion is a sequence of from 2 to 5 (for example 2, 3, 4 or 5) naturally occurring amino acids. For example, the separating portion is a sequence of from 3 to 5 (for example 3, 4 or 5) naturally occurring amino acids. Preferably the separating portion is a sequence of 3 amino acids.

[0249] In certain embodiments, the separating portion has the sequence X20X21X22, wherein X2o is any naturally occurring amino acid, X21 is any naturally occurring amino acid; and X22 is any naturally occurring amino acid; and wherein optionally one or two of X20, X21 or X22 are absent. For example, none of X20, X21 or X22 is absent, one of X20, X21 or X22 is absent, or two of X20, X21 or X22 are absent. More preferably, none of X20, X21 or X22 is absent or one of X20, X21 or X22 is absent. Most preferably none of X20, X21 or X22 is absent, i.e. the separating portion has the sequence X20X21X22, wherein X2o is any naturally occurring amino acid, X21 is any naturally occurring amino acid; and X22is any naturally occurring amino acid.

[0250] Preferably, X20 is S, T, M, P, F, Y or W (for example P or T); X21 is D, E, N or Q; and X22 is G, A, V, L or I; wherein optionally one or two (for example one) of X20, X21 or X22 are absent.

[0251] In preferred embodiments, X20 is S, T, M, P, F, Y or W (for example P or T), X21 is D, E, N or Q; and X22 is G, A, V, L, I. More preferably, X20 is P or T; X21 is N; and X22 is L. For example, the separating portion has the sequence PNL or TNL.

[0252] The N-terminal portion may be absent or may be a sequence of 1 to 15 naturally occurring amino acids. For example, the N-terminal portion may be absent or may be a sequence of from 1 to 10, from 1 to 8, from 1 to 6, or from 1 to 5 naturally occurring amino acids, for example 1, 2, 3, 4 or 5 naturally occurring amino acids.

[0253] In certain embodiments, the N-terminal portion has the sequence X1X2X3X4X5, wherein Xi is any naturally occurring amino acid or is absent; X2 is any naturally occurring amino acid or is absent; X3 is any naturally occurring amino acid or is absent; XHs any naturally occurring amino acid or is absent; and X5 is any naturally occurring amino acid or is absent.

[0254] Preferably, the N-terminal portion has the sequence X1X2X3X4X5, wherein Xi is G, A, V, L, I or is absent, X2 is D, E, N, Q or is absent, X3 is D, E, N, Q or is absent, X4 is H, K, R or is absent, and X5 is F, Y, W or is absent. More preferably, Xi is V, G or absent (for example V or absent); X2 is D or absent; X3 is N or absent; X4 is K or absent; and X5 is F or absent.

[0255] In certain embodiments, preferably none of Xi, X2, X3 ,X4 and X5 is absent; Xi is absent and the other residues are not absent; Xi and X2 are absent and the other residues are not absent; Xi, X2 and X3 are absent and the other residues are not absent; Xi, X2, X3 and X4 are absent and the other residue is not absent; or all of Xi, X2, X3 ,X4 and X5 are absent.

[0256] In certain especially preferred embodiments, the N-terminal portion has the sequence X1X2X3X4X5 wherein Xi is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; Xi is absent, X2 is D, X3 is N, X4 is K, and X5 is F; Xi is absent, X2 is absent, X3 is N, X4 is K, and X5 is F; Xi is absent, X2 is absent, X3 is absent, X4 is K, and X5 is F; Xi is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is F; or Xi is absent, X2 is absent, X3 is absent, XHs absent, and X5 is absent. For example, Xi is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; or Xi is absent, X2 is absent, X3 is absent, X4is absent, and X5 is absent, i.e. the N-terminal portion has the sequence VDNKF, GDNKF or is absent; and more preferably has the sequence VDNKF or is absent.

[0257] In one preferred embodiment, Xi is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F, i.e. the N-terminal portion has the sequence VDNKF or GDNKF; and more preferably the N-terminal portion has the sequence VDNKF.

[0258] In one preferred embodiment, Xi is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is absent, i.e. the N-terminal portion is absent.

[0259] The C-terminal portion may be absent or may be a sequence of 1 to 50 naturally occurring amino acids. For example, the C-terminal portion may be absent or may be a sequence of from 1 to 40, 1 to 35, 1 to 30, from 1 to 25, from 1 to 22, or from 1 to 21 naturally occurring amino acids. Preferably, the C-terminal portion may be absent or may be a sequence of from 10 to 35, 10 to 30, from 15 to 25, from 18 to 22, from 1 to 21 naturally occurring amino acids, for example 18, 19, 20, 21 or 22 naturally occurring amino acids. Preferably, the C-terminal portion has a sequence such that it enhances target binding by the CD16a-binding motif of Helix 1 and Helix 2.

[0260] In certain embodiments, the C-terminal portion is absent or has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein Xssis a sequence of 1 to 14 naturally occurring amino acids, X39 is any naturally occurring amino acid, Xse is any naturally occurring amino acid or is absent, Xs?is any naturally occurring amino acid or is absent, and X58 is any naturally occurring amino acid or is absent, and optionally wherein from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement.

[0261] In certain embodiments, Xss is a sequence of 1 to 9, 1 to 7 or 1 to 5 naturally occurring amino acids. More preferably Xss is a sequence of 1 to 4, for example 1, 2, 3 or 4 amino acids. In one especially preferred embodiment, Xss is any naturally occurring amino acid (i.e. any single (one) naturally occurring amino acid residue). In one preferred embodiment, the C-terminal portion has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, X39is S, T, M, P, F, Yor W, X56 is G, A, V, L, I or is absent, X57 is P or is absent, and X58 is H, K, R or isabsent, and optionally wherein from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is aconservative replacement. In another preferred embodiment, the C-terminal portionhas the sequence PSQSANLLAEAKKLNDAQX56X57X58, wherein X56is G, A, V, L,I or is absent, X57 is P or is absent, and X58 is H, K, R or is absent, and optionallywherein from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. In an especially preferred embodiment, the C-terminal portion has theX38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, X39 is S, X56 is A or isabsent, X57 is P or is absent, and X58 is K or is absent, and optionally wherein from 1to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequenceQSANLLAEAKKLNDAQ are replaced by an alternative residue, for examplereplaced by an alternative residue that is a conservative replacement. In anotherespecially preferred embodiment, the C-terminal portion has thePSQSANLLAEAKKLNDAQX56X57X58, wherein X56 is A or is absent, X57 is P or isabsent, and X58 is K or is absent, and optionally wherein from 1 to 5 (for example 1, 2,3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement.For example, in certain embodiments the C-terminal portion has the sequenceX38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, and X39 is S; and:X56 is A, X57 is P, and X58 is K; or X56 is A, or X57 is P, and X58 is absent; orX56 is A,X57 is absent, and X58 is absent; or X56 is absent, X57 is absent, and X58 is absent. Insuch embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by analternative residue, for example replaced by an alternative residue that is aconservative replacement. Or, for example, the C-terminal portion has the sequence PSQSANLLAEAKKLNDAQX56X57X58, wherein X56is A, X57is P, and X58is K; or X56is A, or X57is P, and X58is absent; or X56is A, X57is absent, and X58is absent; or X56 is absent, X57 is absent, and X58 is absent. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. In one preferred the C-terminal portion has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, and X39is S; and X56is A, X57 is P, and X58 is K. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. Or, for example, the C-terminal portion has the sequence PSQSANLLAEAKKLNDAQX56X57X58, wherein X56is A, X57is P, and X58is K. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement.In an alternative preferred embodiment the C-terminal portion has the sequenceX38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, and X39 is S; and: X56 is absent, X57 is absent, and X58 is absent. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. Or, for example, For example, the C-terminal portion has the sequence PSQSANLLAEAKKLNDAQX56X57X58, X56is absent, X57is absent, and X58is absent. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. In one embodiment, the N-terminal portion has the sequence X1X2X3X4X5 wherein X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; X1 is absent, X2 is D, X3is N, X4is K, and X5is F; X1is absent, X2is absent, X3is N, X4is K, and X5is F; X1is absent, X2is absent, X3is absent, X4is K, and X5is F; X1is absent, X2is absent, X3is absent, X4is absent, and X5is F; or X1is absent, X2is absent, X3is absent, X4isabsent, and X5 is absent (for example, X1 is V or G (preferably V), X2 is D, X3 is N, X4is K, and X5 is F, or X1 is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is absent); and the C-terminal portion has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, X39 is S, T, M, P, F, Yor W, X56 is G, A, V, L, I or is absent, X57 is P, and X58 is H, K, or R, and optionallywherein from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues inthe sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement; and more preferably X38is P, X39is S, X56is A, X57is P, and X58is K, and optionally from1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequenceQSANLLAEAKKLNDAQ are replaced by an alternative residue, for examplereplaced by an alternative residue that is a conservative replacement.In another embodiment, the N-terminal portion has the sequence X1X2X3X4X5wherein X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; X1 is absent, X2 is D, X3 is N, X4 is K, and X5 is F; X1 is absent, X2 is absent, X3 is N, X4 is K, and X5is F; X1is absent, X2is absent, X3is absent, X4is K, and X5is F; X1is absent, X2is absent, X3is absent, X4is absent, and X5is F; or X1is absent, X2isabsent, X3 is absent, X4 is absent, and X5 is absent (for example, X1 is V or G(preferably V), X2is D, X3is N, X4is K, and X5is F, or X1is absent, X2is absent, X3is absent, X4 is absent, and X5 is absent); and the C-terminal portion has the sequencePSQSANLLAEAKKLNDAQX56X57X58, wherein X56 is G, A, V, L, I or is absent, X57is P, and X58 is H, K, or R, and optionally wherein from 1 to 5 (for example 1, 2, 3, 4or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement; and morepreferably X56 is A, X57 is P, and X58 is K, and optionally from 1 to 5 (for example 1,2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. In one very preferred embodiment, X1is V or G (preferably V), X2is D, X3is N, X4isK, and X5 is F; and X56 is G, A, V, L or I (preferably A), X57 is P, and X58 is H, K, or R(preferably K). In an alternative very preferred embodiment X1 is absent, X2 is absent, X3 is absent, X4is absent, and X5 is absent; and X56 is G, A, V, L or I (preferably A), X57 is P, and X58is H, K, or R (preferably K). In another preferred embodiment, the N-terminal portion has the sequence X1X2X3X4X5, wherein X1is G, A, V, L, or I, X2is D, E, N, or Q, X3is D, E, N, or Q,X4 is H, K, or R, and X5 is F, Y, or W (for example, X1 is V or G (preferably V), X2 isD, X3 is N, X4 is K, and X5 is F); and the C-terminal portion has sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38is P, X39is S, T, M, P, F, Yor W (preferably S); and X56 is G, A, V, L or I (preferably A), X57 is P, and X58 is H,K, or R (preferably K); X56 is G, A, V, L or I (preferably A), X57 is P, and X58 isabsent; X56 is G, A, V, L or I (preferably A), X57 is absent, and X58 is absent; or X56 isabsent, X57 is absent, and X58 is absent. More preferably, X56 is G, A, V, L or I(preferably A), X57 is P, and X58 is H, K, or R (preferably K); or X56 is absent, X57 is absent, and X58 is absent. In such embodiments optionally from 1 to 5 (for example 1,2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequenceQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement.In one preferred embodiment, the N-terminal portion has the sequence X1X2X3X4X5,wherein X1is G, A, V, L, or I, X2is D, E, N, or Q, X3is D, E, N, or Q, X4is H, K, orR, and X5 is F, Y, or W (for example, X1 is V or G (preferably V), X2 is D, X3 is N, X4is K, and X5 is F); and the C-terminal portion has sequencePSQSANLLAEAKKLNDAQX56X57X58, wherein X56 is G, A, V, L or I (preferablyA), X57 is P, and X58 is H, K, or R (preferably K); X56 is G, A, V, L or I (preferably A),X57 is P, and X58 is absent; X56 is G, A, V, L or I (preferably A), X57 is absent, and X58is absent; or X56 is absent, X57 is absent, and X58 is absent. More preferably, X56 is G,A, V, L or I (preferably A), X57 is P, and X58 is H, K, or R (preferably K); or X56 isabsent, X57 is absent, and X58 is absent. In such embodiments optionally from 1 to 5 (for example 1, 2, 3, 4 or 5; preferably 1, 2 or 3) of the residues in the sequence PSQSANLLAEAKKLNDAQ are replaced by an alternative residue, for example replaced by an alternative residue that is a conservative replacement. In one very preferred embodiment, X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; and X56 is absent, X57 is absent, and X58 is absent. In an alternative very preferred embodiment, X1is V or G (preferably V), X2is D, X3is N, X4 is K, and X5 is F; X56 is G, A, V, L or I (preferably A), X57 is P, and X58 is H,K, or R (preferably K). In certain embodiments, (i) the separating portion has the sequence X20X21X22; and / orthe N-terminal portion has the sequence X1X2X3X4X5 ; and / or the C-terminal portionhas the sequence PSQSANLLAEAKKLNDAQX56X57X58;wherein, in said separating portion, X20 is P or T; X21 is N; X22 is L;wherein in said N-terminal portion, X1 is V or G (preferably V), or absent; X2 is D orabsent; X3 is N or absent; X4 is K or absent; X5 is F or absent; and wherein in said C-terminal portion, X56 is A or absent; X57 is P or absent; X58 is K or absent.Alternatively, (ii) the separating portion, N-terminal portion, and C-terminal portionare as defined in (i) above, wherein optionally(a) within each portion 1, 2 or 3 residues are replaced by an alternative residue; or (b) within those portions taken together at least 1 and no more than 5 (for example, 1, 2, 3, 4, or 5) residues are replaced by an alternative residue.In such embodiments, preferably the separating portion has the sequence PNL orTNL. Alternatively, or additionally, in such embodiments, the N-terminal portion hasthe sequence VDNKF.In one embodiment, the N-terminal portion may comprise the sequence X1X2X3X4X5,wherein: X1 is V, or absent; X2 is D or absent; X3 is N or absent; X4 is K or absent; X5 is F or absent. For example, the N-terminal portion may comprise the sequence VDNKF. The separating portion may comprise the sequence X20X21X22, wherein: X20is P or T; X21is N; X22is L. For example, the separating portion may comprise the sequence PNL. The C-terminal portion may comprise the sequence PSQSANLLAEAKKLNDAQX56X57X58, wherein: X56 is A or absent; X57 is P or absent; X58 is K or absent. For example, the C-terminal portion may comprise the sequencePSQSANLLAEAKKLNDAQAPK or PSQSANLLAEAKKLNDAQ. The C-terminalportion may have the structure [Second separating portion]-[Helix 3]-[C-terminal sequence]. For example: -the Second separating portion comprises the sequence PS;- the Helix 3 portion comprises the sequence QSANLLAEAKKLNDAQ;- and the C-terminal sequence comprises the sequence APK or is absent.In such embodiments, within those five portions (N-terminal portion, separating portion, second separating portion, Helix 3, and C-terminal sequence) taken together, at least 1 and no more than 8 (for example 5) of the residues may be replaced by an alternative residue. For example, the number of replaced residues is at least 1 and no more than 7, at least 1 and no more than 6, at least 1 and no more than 5, at least 1 andno more than 4, for example at least 1 and no more than 3, for example at least 1 andno more than 2. Particularly, there may be 1, 2, 3, 4 or 5 replacement residues in total in those portions. Thus, in such embodiments, across the entire CD16a-binding polypeptide of the invention (i.e. across the entire overall structure [N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion]), at least 1 and no more than 11 ofthe residues may be replaced by an alternative residue. For example, the number ofreplaced residues is at least 1 and no more than 10, for example at least 1 and no more than 9, for example at least 1 and no more than 8, for example at least 1 and no more than 7, for example at least 1 and no more than 6. Particularly, there may be 1, 2, 3, 4, 5, 6, 7,8, 9, 10 or 11 replacement residues in total across the entire overall structure [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion].In advantageous embodiments of CD16a -binding polypeptides of the invention,where the C-terminal portion comprises a helical or substantially helical region (for example Helix 3 as described immediately above; for example the sequence QSANLLAEAKKLNDAQ), Proline (P) and Cysteine (C) are not present in that helical or substantially helical region. In another embodiment, additionally Glycine (G) is also not present in that helical or substantially helical region for example Helix 3 as described immediately above; for example the sequence QSANLLAEAKKLNDAQ). In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO. 1 to 75 as shown in the Table in Figure 23 and SEQ IDNO: 1001 to 1013 and 1043 (as shown in the table Figure 29). In such sequences,optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence arereplaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptide comprises asequence selected from SEQ ID NO: 1 to 75 and SEQ ID NO 1001 to 1013 and 1043.In one embodiment, the CD16a binding polypeptide has a sequence selected from thegroup consisting of SEQ ID NO: 1 to 75 and SEQ ID NO: 1001 to 1013 and 1043.In one aspect of the invention, the CD16a binding polypeptide comprises a sequence selected from SEQ ID NO.1 to 73 as shown in the Table in Figure 23. In suchsequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in thesequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from SEQ ID NO: 1 to 73. In one embodiment, theCD16a binding polypeptide has a sequence selected from the group consisting of SEQID NO: 1 to 73.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO: 11 to 73 as shown in the Table Figure 23. In suchsequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in thesequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from SEQ ID NO. 11 to 73. In one embodiment, theCD16a binding polypeptide has a sequence selected from the group consisting of SEQID NO: 11 to 73. In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO. 1 to 67 as shown in the Table in Figure 23. In suchsequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in thesequence are replaced by an alternative residue, and, preferably, a residue that is aconservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from SEQ ID NO: 11 to 67. In one embodiment, theCD16a binding polypeptide has a sequence selected from the group consisting of SEQID NO: 1 to 67.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO: 1001 to 1013 and 1043 as shown in the Table in Figure29. In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a bindingpolypeptide comprises a sequence selected from SEQ ID NO: 1001 to 1013 and 1043.In one embodiment, the CD16a binding polypeptide has a sequence selected from thegroup consisting of SEQ ID NO: 1001 to 1013 and 1043.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO: 19, 33, 17, 29, 53, 16, 25, 15, 51, 36, 49, 55, 43, 24, 56,12, 28, 21, 59, 52, 32, 18, 27, 35 and 11 as shown in the Table in Figure 23. In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from of SEQ ID NO: 19, 33, 17, 29, 53, 16, 25, 15, 51,36, 49, 55, 43, 24, 56, 12, 28, 21, 59, 52, 32, 18, 27, 35 and 11. In one embodiment, the CD16a binding polypeptide has a sequence selected from the group consisting ofSEQ ID NO: 19, 33, 17, 29, 53, 16, 25, 15, 51, 36, 49, 55, 43, 24, 56, 12, 28, 21, 59,52, 32, 18, 27, 35 and 11. In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO. 34, 45 and 51 as shown in the Table in Figure 23. In suchsequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from of SEQ ID NO: 34, 45 and 51. In one embodiment, the CD16a binding polypeptide has a sequence selected from the groupconsisting of SEQ ID NO: 34, 45 and 51.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO. 26, 35 and 47 as shown in the Table in Figure 23. In suchsequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is aconservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from of SEQ ID NO: 26, 35 and 47. In oneembodiment, the CD16a binding polypeptide has a sequence selected from the groupconsisting of SEQ ID NO: 26, 35 and 47.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID Nos: 1, 12, 17, 19, 29, 33, 35, 49, 51, and 53 as shown in theTable in Figure 23. In such sequences, optionally from 1 to 5 (preferably optionally1, 2 or 3) residues in the sequence are replaced by an alternative residue, andpreferably a residue that is a conservative replacement. In one embodiment, theCD16a binding polypeptide comprises a sequence selected from SEQ ID NO: 1, 12,17, 19, 29, 33, 35, 49, 51, and 53. In one embodiment, the CD16a bindingpolypeptide has a sequence selected from the group consisting of SEQ ID NO: 1, 12,17, 19, 29, 33, 35, 49, 51, and 53. In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID NO: 17, 19, 29, 33, 35 and 53 as shown in the Table in Figure23. In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3)residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a bindingpolypeptide comprises a sequence selected from of SEQ ID NOs: 17, 19, 29, 33, 35and 53. In one embodiment, the CD16a binding polypeptide has a sequence selectedfrom the group consisting of SEQ ID Nos: 17, 19, 29, 33, 35 and 53.In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID Nos: 15, 17, 35, 19, and 51 as shown in the table Figure 23. Insuch sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptidecomprises a sequence selected from of SEQ ID NOs. 15, 17, 19, 35 and 51. In oneembodiment, the CD16a binding polypeptide has a sequence selected from the group consisting of SEQ ID NOs.15, 17, 19, 35 and 51. In one aspect of the invention, the CD16a binding polypeptide comprises a sequence selected from SEQ ID NO.15, 17 and 19 as shown in the Table in Figure 23. In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptide comprises a sequence selected from of SEQ ID NO.15, 17 and 19. In one embodiment, the CD16a binding polypeptide has a sequence selected from the groupconsisting of SEQ ID Nos: 15, 17 and 19.In one aspect of the invention, the CD16a binding polypeptide comprises a sequence selected from SEQ ID NO. 1, 17, 19, 35 and 51 (as shown in the table in Figure 23) and 1001 (as shown in the table Figure 29). In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptide comprises a sequence selected from ofSEQ ID Nos: 1, 17, 19, 35, 51 and 1001. In one embodiment, the CD16a bindingpolypeptide has a sequence selected from the group consisting of SEQ ID Nos: 1, 17,19, 35, 51 and 1001. In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID Nos: 17, 19, 35 and 51 (as shown in the Table in Figure 23),and 1001(as shown in the table Figure 29). In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternativeresidue, and preferably a residue that is a conservative replacement. In oneembodiment, the CD16a binding polypeptide comprises a sequence selected from ofSEQ ID Nos: 17, 19, 35, 51 and 1001. In one embodiment, the CD16a bindingpolypeptide has a sequence selected from the group consisting of SEQ ID Nos: 17, 19,35, 51 and 1001. In one aspect of the invention, the CD16a binding polypeptide comprises a sequenceselected from SEQ ID Nos: 1, 35 and 51 (as shown in the Table in Figure 23) andSEQ ID NO: 1001 (as shown in the Table in Figure 29). In such sequences, optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement. In one embodiment, the CD16a binding polypeptide comprises a sequence selected from of SEQ ID NO.1, 3551 and 1001. In one embodiment, the CD16a binding polypeptide has a sequence selected from the group consisting of SEQID NO: 1, 35, 51 and 1001.In one aspect of the invention, the CD16a binding polypeptide comprises the sequenceSEQ ID NO. 1001, as shown in the Table in Figure 29. In such a sequence,optionally from 1 to 5 (preferably optionally 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservativereplacement. In one embodiment, the CD16a binding polypeptide comprises asequence selected from SEQ ID NO: 1001. In one embodiment, the CD16a bindingpolypeptide has a sequence selected from the group consisting of SEQ ID NO: 1001.In one aspect of the invention, the CD16a binding polypeptide comprises thesequence: a*)VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLA EAKKLNDAQAPK [SEQ ID NO: 1];In a further aspect of the invention the CD16a binding polypeptide comprises thesequence: b*)VDNKFNKEQFYARDEIDLLPNLNEDQKWAFYMSLIDDPSQSANLL AEAKKLNDAQAPK [SEQ ID NO: 2]; In a further aspect of the invention the CD16a binding polypeptide comprises the sequence: c*)VDNKFNKEFWIAESEIESLPNLNIYQKWAFKYSLADDPSQSANLLA EAKKLNDAQAPK [SEQ ID NO: 3]. As discussed above, a number of residues in the polypeptides of the invention may be substituted by an alternative residue. For example, in a polypeptide as set out in a*),b*) or c*) immediately above (or SEQ ID No. 35 or 51 immediately above), at least 1and no more than 5 of the residues may be replaced by an alternative residue. For example, the number of replaced residues is at least 1 and no more than 4, for example at least 1 and no more than 3, for example 1 at least 1 and no more than 2. Particularly, there may be 1, 2, 3, 4 or 5 replacement residues in total in those portions. As there are 58 residues in polypeptides of this aspect of the invention, a peptide with 5 residues replaced has 91% sequence identity (91.4%) with the recited sequence. For replacement of 4 residues, it is 93% (93.1%), for replacement of 3residues, it is 95% (94.8%), for replacement of 2 residues it is 97% (96.6%) and forreplacement of 1 residue it is 98% sequence identity (98.3%).As mentioned above, in an embodiment, a*) Helix 1 comprises the sequence VQMAQFEIRK and Helix 2 comprises the sequence HHQSFAFIKSLM. In that embodiment, as in others, a number of residues may each be substituted by an alternative residue, as described herein. In any such alternative polypeptides of the invention with alternative residues in place, binding to the CD16a receptor is maintained. For example, the CD16a binding efficacy is at least 1% of the binding efficacy of the peptide of SEQ ID NO: 1 to the CD16a receptor, when measured under the same conditions. With 1% binding efficacy, it is understood that the IC50concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 100 times the IC50 concentration for the peptide of SEQ ID NO: 1 to the CD16a receptor, when measured under the same conditions. More preferably, the binding efficacy is at least 5%, 10%, 20%, 25% or 50% of the binding efficacy of the peptide of SEQ ID NO: 1 to the CD16a receptor, when measured under the same conditions. That is to say that the IC50concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 20 times, 10 times, 5 times, 4 times or 2 times the IC50 concentration for the peptide of SEQ ID NO: 1 to the CD16a receptor, when measured under the same conditions. As also mentioned above, in an embodiment, b*) Helix 1 comprises the sequence QFYARDEIDL and Helix 2 comprises the sequence EDQKWAFYMSLI. In that embodiment, as in others, a number of residues may each be substituted by an alternative residue, as described herein. In any such alternative polypeptides of the invention with alternative residues in place, binding to the CD16a receptor is maintained. For example, the CD16a binding efficacy is at least 1% of the binding efficacy of the peptide of SEQ ID NO: 74 to the CD16a receptor, when measured under the same conditions. With 1% binding efficacy, it is understood that the IC50concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 100 times the IC50 concentration for the peptide of SEQ ID NO: 74 to the CD16a receptor, when measured under the same conditions. More preferably, the binding efficacy is at least 5%, 10%, 20%, 25% or 50% of the binding efficacy of the peptide of SEQ ID NO: 74 to the CD16a receptor, when measured under the same conditions. That is to say that the IC50 concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 20 times, 10 times, 5 times, 4 times or 2 times the IC50concentration for the peptide of SEQ ID NO: 74 to the CD16a receptor, when measured under the same conditions. As also mentioned above, in an embodiment, c*) Helix 1 comprises the sequence FWIAESEIES and Helix 2 comprises the sequence IYQKWAFKYSLA. In that embodiment, as in others, a number of residues may each be substituted by an alternative residue, as described herein. In any such alternative polypeptides of the invention with alternative residues in place, binding to the CD16a receptor is maintained. For example, the CD16a binding efficacy is at least 1% of the binding efficacy of the peptide of SEQ ID NO: 75 to the CD16a receptor, when measured under the same conditions. With 1% binding efficacy, it is understood that the IC50 concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 100 times the IC50concentration for the peptide of SEQ ID NO: 75 to the CD16a receptor, when measured under the same conditions. More preferably, the binding efficacy is at least 5%, 10%, 20%, 25% or 50% of the binding efficacy of the peptide of SEQ ID NO: 75 to the CD16a receptor, when measured under the same conditions. That is to say that the IC50concentration of the alternative polypeptide for binding to the CD16a receptor is no more than 20 times, 10 times, 5 times, 4 times or 2 times the IC50 concentration for the peptide of SEQ ID NO: 75 to the CD16a receptor, when measured under the same conditions.The invention further provides a CD16a-binding polypeptide, wherein the CD16a-binding polypeptide consists of one motif that binds to CD16a, wherein saidpolypeptide consists of the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion] the CD16a binding motif being the portion [Helix 1]-[Separating portion]-[Helix 2]; the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule;and optionally the peptide further comprises one or more further additional functionalportions as described below (for example 1, 2, 3, 4, 5, 6 ore more); for example one, two or three additional functional portions.In one preferred embodiment the CD16a-binding polypeptide (for example a CD16a-binding polypeptide of the invention described above or below) consists of one motifthat binds to CD16a, wherein said polypeptide consists of the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion] the CD16a binding motif being the portion [Helix 1]-[Separating portion]-[Helix 2] the CD16a-binding polypeptide further consisting of at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule;(and optionally further comprises one or more further additional functional portions asdescribed below (for example 1, 2, 3, 4, 5, 6 ore more); for example one, two or three additional functional portions). In a further aspect, the invention provides a CD16a-binding polypeptide whichcomprises at least one motif that binds to CD16a, wherein said polypeptide comprisesthe following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]- [Helix 2], wherein the sequence of the CD-16a-binding motif is selected from SEQ ID NOs 1014 to 1026 and 1044 The invention further provides a CD16a-binding which comprises at least one motif that binds to CD16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]- [Helix 2], wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID NOs: 1001 to 1013 and 1043.Multimeric CD16a-binding polypeptides: CD16a-binding oligomersThe present invention further provides CD16a-binding oligomers which comprise atleast two (i.e. two, or more than two, for example 2, 3, 4, 5, 6 or more; preferably 2, 3or 4) CD16a-binding motifs as recited for the CD16a-binding polypeptides of thepresent invention. In one preferred embodiment, CD16a-binding oligomer of thepresent invention comprises two CD16a-binding motifs of the polypeptides of thepresent invention. In another embodiment, a CD16a-binding oligomer of the presentinvention comprises at least three, at least four, at least 5 or at least 6 CD16a-bindingmotifs of the polypeptides of the present invention, for example 3, 4, 5 or 6 or more CD16a-binding motifs of the polypeptides of the present invention. The CD16a-binding polypeptides of a CD16a-binding oligomer of the invention may optionally be connected via one or more linkers. A CD16a-binding oligomer of the present invention is a multimeric binder, as it has multiple CD16a binding motifs, i.e. it has a CD16a binding motif ([Helix 1]-[Separating portion]-[Helix 2]) in each CD16a-binding polypeptide it comprises.This aspect of the invention may also be defined such that the CD16a bindingpolypeptide constitutes two or more CD16a-binding moieties or CD16a-bindingpeptides, optionally connected via one or more linkers, for example two, three, four,five, six or more CD16a-binding moieties or CD16a-binding peptides, optionallyconnected via one or more linkers, for example two, three, or four CD16a-bindingmoieties optionally connected via one or more linkers. This definition is used in the numbered embodiments of the invention below to refer to the CD16a-binding oligomers aspects of the invention.A CD16a-binding oligomer of the present invention comprises, at least, a first CD16a-binding motif of the polypeptide of the present invention, and a second CD16a-binding motif of the polypeptide of the present invention. The first and secondCD16a-binding motifs may have the same sequence. Alternatively, the first andsecond CD16a-binding motifs may have different sequences. A CD16a-bindingoligomer of the present invention may optionally further comprise a third CD16a-binding motif of the polypeptide of the present invention. The third CD16a-bindingmotif may have the same sequence as the first and / or second CD16a-binding motif sequences. Alternatively, the third CD16a-binding motif may have a differentsequence to the first and second CD16a-binding motif. A CD16a-binding oligomer ofthe present invention may optionally further comprise a fourth CD16a-binding motifof the present invention. The fourth CD16a-binding motif may have the samesequence as the first and / or second and / or third CD16a-binding motif sequences. Alternatively, the fourth CD16a-binding motif may have a different sequence to the first, second and third CD16a-binding motif.In one preferred embodiment, a CD16a-binding oligomer of the present inventioncomprises a first CD16a-binding polypeptide that comprises a first binding motifselected from SEQ ID Nos: 150 to 221 and 1014 to 1026 and 1044 (and whereinoptionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced byan alternative residue, and preferably a residue that is a conservative replacement); and a second CD16a-binding polypeptide that comprises a second binding motifselected from SEQ ID Nos: 150 to 221 and 1014 to 1026 and 1044 (and whereinoptionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced byan alternative residue, and is, preferably, a residue that is a conservative replacement).The first and second CD16a-binding motifs may have the same sequence or adifferent sequence.In one preferred embodiment, a CD16a-binding oligomer of the present inventioncomprises a first CD16a-binding polypeptide that comprises a first binding motif selected from SEQ ID NOs.150 to 221 (and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement); and a second CD16a- binding polypeptide that comprises a second binding motif selected from SEQ IDNOs. 150 to 221 (and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues inthe sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement). The first and second CD16a-binding motifs may have the same sequence or a different sequence.In one preferred embodiment, a CD16a-binding oligomer of the present inventioncomprises a first CD16a-binding polypeptide that has a sequence selected from SEQID Nos: 1-75 and 1001 to 1013 and 1043 (and wherein optionally from 1 to 5(preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue,and preferably a residue that is a conservative replacement); and a second CD16a-binding polypeptide that has sequence selected from SEQ ID Nos: 1-75 and 1001 to1013 and 1043 (and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues inthe sequence are replaced by an alternative residue, and preferably a residue that is aconservative replacement). The first and second CD16a-binding polypeptide mayhave the same sequence or a different sequence.In one preferred embodiment, a CD16a-binding oligomer of the present inventioncomprises a first CD16a-binding polypeptide that has a sequence selected from SEQID Nos: 1-75 (and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues inthe sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement); and a second CD16a-binding polypeptide that hassequence selected from SEQ ID Nos: 1-75 (and wherein optionally from 1 to 5(preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement). The first and second CD16a-binding polypeptide may have the same sequence or a different sequence.In another embodiment, a CD16a-binding oligomer of the present invention comprisesa first CD16a-binding polypeptide that has a sequence selected from SEQ ID Nos: 1-75 and 1001 to 1013 and 1043 (and wherein optionally from 1 to 5 (preferably 1, 2 or3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement); a second CD16a-binding polypeptide thathas sequence selected from SEQ ID Nos: 1-75 and 1001 to 1013 and 1043 (andwherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement); and a third CD16a-binding polypeptide that has sequence selected fromSEQ ID Nos: 1-75 and 1001 to 1013 and 1043 (and wherein optionally from 1 to 5(preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue,and preferably a residue that is a conservative replacement). The first, second and third CD16a-binding polypeptide may have the same sequence, or each have a different sequence, or two sequences may be the same and one may be different). Optionally, a fourth CD16a-binding polypeptide that has sequence selected from SEQID Nos: 1-75 and 1001 to 1013 and 1043 (and wherein optionally from 1 to 5(preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue,and preferably a residue that is a conservative replacement) may be present; whichmay be the same as any one of the first, second, or third sequences, or may be different.In one preferred embodiment, a CD16a-binding oligomer of the present inventioncomprises a first CD16a-binding polypeptide that has a sequence selected from SEQID Nos: 1, 35, 74, 75, 51 or 1001 (for example 1, 74 or 75, for example 1, 51 or 1001)(and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement); and a second CD16a-binding polypeptide that has sequence selectedfrom SEQ ID Nos: 1, 35, 74, 75, 51 or 1001 (for example 1, 74 or 75, for example 1,51 or 1001) (and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in thesequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement). The first and second CD16a-binding polypeptide may have the same sequence or a different sequence (for example, the first CD16a-bindingpolypeptide may have SEQ ID NO: 1; and the second CD16a-binding polypeptidemay have SEQ ID NO: 1; or the first CD16a-binding polypeptide may have SEQ IDNO: 74; and the second CD16a-binding polypeptide may have SEQ ID NO: 1; thefirst CD16a-binding polypeptide may have SEQ ID NO.75; and the second CD16a-binding polypeptide may have SEQ ID NO: 1).The CD16a-binding polypeptides in a CD16a-binding oligomer of the presentinvention may be separated by a linker. For example, each CD16a-bindingpolypeptide in a CD16a-binding oligomer of the present invention may be separatedby a linker. Preferably, the linker is a linker as defined herein, for example a flexible amino acid linker, a rigid amino acid linker or cleavable amino acid linker or non-amino acid linker. Where a CD16a-binding oligomer of the present inventioncomprises more than one linker, the linkers may be the same, or may be different.Preferably, a linker for a CD16a-binding oligomer of the present invention comprisesor has a sequence of 1 to 50 (for example 1 to 25, for example 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25) naturally occurringamino acids; and preferably 1 to 20 (for example 1, 5, 10, 15, or 20; and morepreferably 1 to 15) naturally occurring amino acids, for example selected from thegroup consisting of G, S and T (preferably G and S).In one preferred embodiment, a linker for a CD16a-binding oligomer of the presentinvention is G or comprises or has sequence GGGSG, GGGGS, GGSGG, GSGGGand / or SGGGG; for example the linker is G or comprises or has the sequenceGGGSG, GGGSGGGGSG,GGGSGGGGSGGGGSG,GGGSGGGGSGGGGSGGGGSG, GGGGS,GGGGSGGGGS, GGGGSGGGGSGGGGS, GGGGSGGGGSGGGGSGGGGS, GGSGG, GGSGGGGSGG, GGSGGGGSGGGGSGG, GGSGGGGSGGGGSGGGGSGGGGSGG, GSGGG, GSGGGGSGGG, GSGGGGSGGGGSGGG, GSGGGGSGGGGSGGGGSGGG, SGGGG, SGGGGSGGGG, SGGGGSGGGGSGGGG, or SGGGGSGGGGSGGGGSGGGG.In one preferred embodiment, a linker for a CD16a-binding oligomer of the presentinvention is G or comprises or has sequence GGGSG; for example the linker comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG or GGGSGGGGSGGGGSGGGGSG. In another embodiment, a linker for a CD16a-binding oligomer of the present invention comprises or has sequence GGGGS; forexample the linker comprises or has the sequence GGGGS, GGGGSGGGGS,GGGGSGGGGSGGGGS or GGGGSGGGGSGGGGSGGGGS.In one embodiment, preferably the linker comprises one or more group selected fromthe group consisting of triazole (for example a 1,4- or 1,5-substituted triazole), abicyclic ring comprising a triazole ring (for example a triazole fused cyclooctane,mono- or di-fluorocyclooctane), a tricyclic ring comprising a triazole ring (for example a triazole fused bicyclononane), a tetracyclic ring comprising a triazole ring (for example a triazole fused dibenzocyclooctane or dibenzoazacyclooctane ring), a bicyclic ring comprising a pyridazine ring (for example a pyridazine fused cyclooctane), a tricyclic ring comprising a pyridazine ring (for example pyridazine fused bicyclononane), 1H-pyrrole-2,5-dione, wherein n is 1 to 30, wherein z is 1 to 4. Such linkers may be referred to as ‘synthetic’. For the avoidance of doubt, a wavy line when used in a definition of a group herein denotes attachment points of the group, which could be, for example, to a further linker group, to a hydrogen, to a CD16a binding polypeptide, or CD16a binding oligomer, or additional functional portion (for example an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is apolypeptide, peptide or small molecule; or for example a BCMA binding polypeptide)of the present invention.Alternatively, CD16a-binding polypeptides in a CD16a-binding oligomer of thepresent invention may not be separated by a linker (i.e. they may be directly attached to each other). In one preferred embodiment, a CD16a-binding oligomer does not comprise a linker.In one embodiment, the CD16a-binding oligomer of the present invention comprisesat least 2 (for example 2) CD16a-binding polypeptides, and the CD16a-bindingoligomer comprises the following structure:[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]- [linker]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]; wherein each N-terminal portion in the oligomer may have the same sequence or have different sequences; each C-terminal portion in the oligomer may have the same sequence or have different sequences; each separating portion in the oligomer may have the same sequence or have different sequences; each Helix 1 portion in the oligomer may have the same sequence or have different sequences; and each Helix 2 portion in the oligomer may have the same sequence or have different sequences.In such embodiments, the linker preferably comprises or has a sequence of 1 to 25(for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24 or 25) naturally occurring amino acids; and preferably 1 to 20 (for example 1, 5, 10, 15, or 20; and more preferably 1 to 15) naturally occurring amino acids, forexample selected from the group consisting of G, S and T (preferably G and S).For example, the linker is G or comprises or has sequence GGGSG, GGGGS,GGSGG, GSGGG and / or SGGGG; for example, wherein the linker is G or comprisesor has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG, GGGSGGGGSGGGGSGGGGSG, GGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS, GGGGSGGGGSGGGGSGGGGS, GGSGG, GGSGGGGSGG, GGSGGGGSGGGGSGG, GGSGGGGSGGGGSGGGGSGGGGSGG, GSGGG, GSGGGGSGGG, GSGGGGSGGGGSGGG, GSGGGGSGGGGSGGGGSGGG, SGGGG, SGGGGSGGGG, SGGGGSGGGGSGGGG, or SGGGGSGGGGSGGGGSGGGG. In one embodiment, preferably the linker comprises one or more group selected the linkers described above and termed ‘synthetic linkers’.Alternatively, the linker may be absent, i.e. the CD16a-binding oligomer comprisesthe following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]- [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion].In one embodiment, the CD16a-binding oligomer comprises the sequenceVDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLN DAQAPKGGGSGGGGSGGGGSGVDNKFNKEVQMAQFEIRKLPNLNHHQSFAF IKSLMDDPSQSANLLAEAKKLNDAQAPK [SEQ ID NO.242], and wherein optionally 1, 2 or 3 residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement.In another embodiment, the CD16a-binding oligomer comprises the sequenceVDNKFNKEQFYARDEIDLLPNLNEDQKWAFYMSLIDDPSQSANLLAEAKKLN DAQAPKGGGSGGGGSGGGGSGVDNKFNKEVQMAQFEIRKLPNLNHHQSFAF IKSLMDDPSQSANLLAEAKKLNDAQAPK SEQ ID NO.243], and wherein optionally 1, 2 or 3 residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement.In another embodiment, the CD16a-binding oligomer comprises the sequenceVDNKFNKEFWIAESEIESLPNLNIYQKWAFKYSLADDPSQSANLLAEAKKLN DAQAPKGGGSGGGGSGGGGSGVDNKFNKEVQMAQFEIRKLPNLNHHQSFAF IKSLMDDPSQSANLLAEAKKLNDAQAPK [SEQ ID NO.244], and wherein optionally 1, 2 or 3 residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement.In a further embodiment, a CD16a-binding oligomer of the present invention maycomprise two CD16a-binding polypeptides, each of which has a sequence in which Helix 1 comprises the sequence VQMAQFEIRK and Helix 2 comprises the sequence HHQSFAFIKSLM. As set out elsewhere, such sequences may have a number of residues substituted by an alternative residue. For example, each of the two CD16-a binding polypeptides may have the sequence: VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLN DAQAPK [SEQ ID NO: 1]. In an alternative example, a CD16a-binding oligomer of the present invention may comprise two CD16a-binding polypeptides, one of which has a sequence in which Helix 1 comprises the sequence QFYARDEIDL and Helix 2 comprises the sequence EDQKWAFYMSLI, and the other of which has a sequence in which Helix 1 comprises the sequence VQMAQFEIRK and Helix 2 comprises the sequence HHQSFAFIKSLM. As set out elsewhere, such sequences may have a number of residues substituted by an alternative residue. For example, one of the two CD16a binding polypeptides may have the sequence: VDNKFNKEQFYARDEIDLLPNLNEDQKWAFYMSLIDDPSQSANLLAEAKKLN DAQAPK [SEQ ID NO: 2] and The other may have the sequence: VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLN DAQAPK [SEQ ID NO: 1]. In an alternative example, a CD16a-binding oligomer of the present invention may comprise two CD16a-binding polypeptides, one of which has a sequence in which Helix 1 comprises the sequence VQMAQFEIRK and Helix 2 comprises the sequence HHQSFAFIKSLM, and the other of which has a sequence in which Helix 1 comprises the sequence FWIAESEIES and Helix 2 comprises the sequence IYQKWAFKYSLA. As set out elsewhere, such sequences may have a number of residues substituted by an alternative residue. For example, one of the two polypeptides may have the sequence: VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLN DAQAPK [SEQ ID NO: 1] and The other may have the sequence: VDNKFNKEFWIAESEIESLPNLNIYQKWAFKYSLADDPSQSANLLAEAKKLN DAQAPK [SEQ ID NO: 75]. LinkersWhere present, a linker connects together two or more functional portions (definedfurther herein below) of the polypeptides of the invention. For example, a linker mayconnect together two CD16a binding motifs in a polypeptide of the present invention (for example in a CD16a-binding oligomer of the invention), or a linker may connect together a CD16a binding motif of a polypeptide of the present invention and an additional functional portion of a polypeptide of the present invention. A linker may also connect together one additional functional portion in a polypeptide of the presentinvention and a further additional functional portion in a polypeptide of the presentinvention in embodiments where more than one additional functional portion ispresent. A non-amino acid linker may be referred to as a synthetic linker.For the avoidance of doubt, in certain embodiments a linker may not connect together two CD16a binding polypeptides of the present invention (for example in a CD16a- binding oligomer of the invention), and / or a linker may not connect together a CD16a binding polypeptides of the present invention and an additional functional portion of the present invention; and / or a linker may not connect together an additional functional of the present invention and an additional functional portion of the present invention in embodiments where more than one additional functional portion ispresent. For example, in certain embodiments two CD16a binding polypeptides of thepresent invention (for example in a CD16a-binding oligomer of the invention) may be directly connected; and / or a CD16a binding polypeptide or oligomer of the present invention may be directly connected to additional functional portion of the present invention; and / or an additional functional of the present invention may be directly connected to an additional functional portion of the present invention.In one embodiment, the CD16a binding polypeptide according to any aspect disclosedherein, or a CD16a-binding oligomer according to any aspect disclosed herein, furthercomprises at least one linker, such as at least one linker selected from flexible aminoacid linkers, rigid amino acid linkers and cleavable amino acid linkers. In oneembodiment, said linker is between two or more CD16a-binding motifs, for example in a CD16a-binding oligomer of the present invention, or between a CD16a-bindingmotif or a CD16a-binding oligomer and an additional functional portion, for examplean immune signalling molecule or an additional binding moiety, for example anadditional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule.In one embodiment, the CD16a binding oligomer according to any aspect disclosedherein comprises at least one linker, such as at least one linker selected from flexible amino acid linkers, rigid amino acid linkers and cleavable amino acid linkers. Thelinker may be between two or more CD16a-binding polypeptides. A further linkerbetween a CD16a-binding polypeptide or a CD16a-binding oligomer and anadditional functional portion, for example an immune signalling molecule or an additional binding moiety (for example as described in further detail below), may alsobe present in a CD16a binding oligomer according to any aspect disclosed herein. Afurther linker between an additional functional portion (for example an immune signalling molecule or an additional binding moiety (for example as described in further detail below) and an additional functional portion (for example an immune signalling molecule or an additional binding moiety (for example as described in further detail below), may also be present in a CD16a binding oligomer according to any aspect disclosed herein. In embodiments and aspects of the present invention that comprise more than one linker, each linker may be the same, or may be different, or some linkers may be the same, and some may be different (for example in embodiments having 3 or morelinkers (for example 3, 4, 5, 6, 7, 8 or more linkers).Flexible linkers may be used when the linked domains require some distance and conformational freedom, and may be advantageous in some embodiments of the invention. Such linkers are generally composed of small, non-polar (for example G) or polar (for example S or T) amino acids. K may also be used. Some flexible linkersprimarily consist of stretches of G and S residues, for example (GGGGS)p or(GGGSG)p. Other examples include (GGSGG)p, (GSGGG)p or (SGGGG)p.Adjusting the copy number “p” allows optimization of the linker in order to achieveappropriate separation between the functional moieties, or to maintain necessary inter-moiety interaction. In a preferred embodiment, the linker is (GGGSG)p, for example(GGGSG)1, (GGGSG)2 or (GGGSG)3, for example (GGGSG)3. In an embodiment,the linker is (GGGGS)p, for example (GGGGS)1, (GGGGS)2 or (GGGGS)3, for example (GGGGS)3. In an embodiment, the linker is (GGSGG)p, for example (GGSGG)1, (GGSGG)2 or (GGSGG)3, for example (GGSGG)3. In an embodiment, the linker is (GSGGG)p, for example (GSGGG)1, (GSGGG)2 or (GSGGG)3, forexample (GSGGG)3. In an embodiment, the linker is (SGGGG)p, for example(SGGGG)1, (SGGGG)2or (SGGGG)3, for example (SGGGG)3. In another, embodiment, the linker is G.In one embodiment, a linker in a compound of the present invention comprises or hasa sequence of 1 to 50 (for example 1 to 40, 1 to 30, or 1 to 25, for example 1, 2, 3, 4, 56, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25) naturally occurring amino acids; and preferably 1 to 20 (for example 1, 5, 10, 15, or 20; andmore preferably 1 to 15) naturally occurring amino acids, for example selected fromthe group consisting of G, S and T. In one embodiment, a linker in a compound of thepresent invention comprises or has a sequence of 1 to 50 (for example 1 to 25, for example 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25; or 1 to 20, for example 1, 5, 10, 15 or 20; or 1 to 15, for example 1, 5, 10 or 15) naturally occurring amino acids, forexample selected from the group consisting of G and S. For example, a linker in acompound of the present invention is G or comprises or has sequence GGGSG; forexample the linker comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG or GGGSGGGGSGGGGSGGGGSG.Also, for example, a linker in a compound of the present invention is G or comprisesor has sequence GGGSG, GGGGS, GGSGG, GSGGG and / or SGGGG. For example, the linker is G or comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG, GGGSGGGGSGGGGSGGGGSG, GGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS, GGGGSGGGGSGGGGSGGGGS, GGSGG, GGSGGGGSGG, GGSGGGGSGGGGSGG, GGSGGGGSGGGGSGGGGSGGGGSGG, GSGGG, GSGGGGSGGG, GSGGGGSGGGGSGGG, GSGGGGSGGGGSGGGGSGGG, SGGGG, SGGGGSGGGG, SGGGGSGGGGSGGGG, or SGGGGSGGGGSGGGGSGGGG.In one preferred embodiment, a linker in a compound of the present invention is G orcomprises or has sequence GGGSG; for example the linker comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG or GGGSGGGGSGGGGSGGGGSG. In another embodiment, a linker for a CD16a-binding oligomer of the present invention comprises or has sequence GGGGS; forexample the linker comprises or has the sequence GGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS or GGGGSGGGGSGGGGSGGGGS. Apart from G and S linkers, other flexible linkers are known in the art, such as G and S linkers containing additional amino acid residues, such as T and A, to maintain flexibility, as well as polar amino acid residues to improve solubility. In general, it is known in the art that linker sequence and length may affect the characteristics of the linked moieties, and so the skilled person will be able to select an appropriate linkerfor use in the binding polypeptides as described herein.Other types of linkers, such as rigid and / or cleavable linkers, can also be used toconnect domains in multidomain constructs to improve or control their biologicalactivity. Such linkers are known in the art (Chen X et al, Fusion protein linkers:Property, design and functionality, Adv Drug Deliv Rev 2013:65:10:1357, doi: 10.1016 / j.addr.2012.09.039). Alternatively, the different binding moieties of the binding polypeptide as described herein (for example two or more CD16a-binding polypeptides, or a CD16a-bindingpolypeptide and an additional functional portion, for example an immune signallingmolecule or an additional binding moiety) may be covalently linked by a chemicallinker. Such a chemical linker may be produced by, for example, maleimide or ‘click’chemistry. The skilled person will be aware of other linkers suitable for use in thebinding polypeptides as described herein. The CD16a-binding oligomers and CD16a-binding polypeptides of the invention comprising such chemical linkers as described herein (‘synthetic linkers’) may be synthesised by chemical methods, for example by solid phase synthesis, leading to advantages in respect of ease of production and purity of the oligomers and polypeptides, as well as increased choice of spacing and arrangement of the polypeptides and oligomers. This allows modulation of the properties of the polypeptides and oligomers, such as length and flexibility (or rigidity), as well as optimisation of spatial arrangement to maximize biological function. For example, the synthetic linkers in compounds of the present invention allow precise control of distance and conformational freedom between each CD16a-binding polypeptideand / or other functional portion(s), for example between a CD16a-binding polypeptideand an additional binding moiety which is a binding partner recognising a protein inthe B7 family and which is a polypeptide, peptide or small. Control of the ordering and arrangement of targeting domains of the polypeptides and oligomers is also possible. For example the synthetic linkers described herein allow the possibility to connect the N-terminal of a CD16a-binding polypeptide with the N-terminal of another CD16a-binding polypeptide and / or other functional portion, and the possibility to connect the C-terminal of a CD16a-binding polypeptide with the C- terminal of another CD16a-binding polypeptide and / or other functional portion. Using synthetic linkers as described herein also allows the possibility of connecting CD16a-binding polypeptides and / or other functional portion at a position within the N-terminal portion or C-terminal portion of a CD16a-binding polypeptide, as well as using branched linkers. Finally, the synthetic linkers described herein are both stable and non-toxic, and thus are especially suitable for use with the polypeptides and oligomers of the present invention, which find utility as anti-cancer immunotherapeutics. As mentioned above, the CD16a-binding polypeptides in a CD16a-binding oligomer of the present invention may be separated by a linker, for example a linker that comprises one or more group selected from the group consisting of triazole (forexample a 1,4- or 1,5-substituted triazole), a bicyclic ring comprising a triazole ring(for example a triazole fused cyclooctane, mono- or di-fluorocyclooctane), a tricyclicring comprising a triazole ring (for example a triazole fused bicyclononane), a tetracyclic ring comprising a triazole ring (for example a triazole fused dibenzocyclooctane or dibenzoazacyclooctane ring), a bicyclic ring comprising a pyridazine ring (for example a pyridazine fused cyclooctane), a tricyclic ring comprising a pyridazine ring (for example pyridazine fused bicyclononane), 1H- A linker of the type described immediately above in compounds of the present invention is a termed a synthetic linker as it comprises one or more group that is not an amino acid. More specifically, such a linker may comprise one or more groups (for example, one, two, three, four, five or more groups) selected from the groupconsisting of triazole (for example a 1,4- or 1,5-substituted triazole), a bicyclic ringcomprising a triazole ring (for example a triazole fused cyclooctane, mono- or di-fluorocyclooctane), a tricyclic ring comprising a triazole ring (for example a triazole fused bicyclononane), a tetracyclic ring comprising a triazole ring (for example a triazole fused dibenzocyclooxtane or dibenzoazacyclooctane ring), a bicyclic ring comprising a pyridazine ring (for example a pyridazine fused cyclooctane), a tricyclic ring comprising a pyridazine ring (for example pyridazine fused bicyclononane), 1H- pyrrole-2,5-dione, wherein n is 1 to 30, wherein m is 1 Examples of triazole groups include, but are not limited to, 1,4- and 1,5- substitutedtriazole, . . . Preferably the triazole group is 1,4-substituted triazole, . . . Examples of bicyclic rings comprising a triazole ring include, but are not limited totriazole fused cyclooctane and triazole fused mono- or di-fluorocyclooctane, forexample

[0262] Examples of tricyclic rings comprising a triazole ring include, but are not limited to, triazole fused bicyclononane, for example Examples of tetracyclic rings comprising a triazole ring include, but are not limited to,dibenzocyclooctane and dibenzoazacyclooctane, for example ,

[0263] . Examples of bicyclic rings comprising a pyridazine ring include, but are not limited

[0264] Examples of tricyclic rings comprising a pyridazine ring groups include, but are not . The structure of 1H-pyrrole-2,5-dione is as follows: . embodiments, the linker may comprise two 1H-pyrrole-2,5-dione groups, for example, the linker may comprise (for example example 1 to 24, 1 to 12, 1 to 10, 1 to 8, or 2 to 8 (and especially 4) or wherein n is to 1 to 30 (for example 1 to 24 or 1 to 20 (and especially 3, 6, 11 or 19) (for example In embodiments wherein the linker comprises a group, wherein n is 1 to 30, preferably n is 1 to 24 (for example n is 1 to 16, 1 to 12, 1 to 10, 1 to 8, or 2 to 8 (and especially 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 19, 20 or 24; and more especially 2, 3, 4, or 8). In embodiments wherein the linker comprises a group, preferably m is 1 to 16 (for example m is 1 to 12, 1 to 10, 1 to 8 or 2 to 8, and especially 2, 3, 4, or 8). In embodiments wherein the linker comprises group, preferably p is 1 to 10 (for example 1 to 8, or 1 to 6, and especially 1, 2, 4, 6 or 8). In embodiments wherein the linker comprises group, the linker preferably comprises the following structure,

[0265] . In embodiments wherein the linker comprises a group, the linker preferably additionally comprises at least one (for example one) group, wherein n is 1 to 30 (1 to 24, 1 to 16, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 8). For example, the linker may comprise the following , or 2 to 8, and especially 8. In certain embodiments the linker comprises a group, wherein z is 1 to 4 (for example 1 or 2, and preferably 1) and especially a

[0266] or 2, for example z is 2 and the group is certain embodiments, the linker comprises (or is) a group selected from

[0267] In one preferred embodiment, a linker in a compound of the present invention group, wherein y is 1 to 10 (for example, y is 1 to 8 or 1 to 6, especially 3, 4, 5 or 6, and more especially 1 to 5, and most especially 4 or 5). In one such embodiment y is 4, i.e. the linker comprises In another preferred embodiment, a linker in a compound of the present invention comprises group, wherein y is 1 to 10 (for example, y is 1 to 8 or 1 to 6, especially 3, 4, 5 or 6, and more especially 1 to 5, and most especially 4 or 5). In one such embodiment y is 5, i.e. the linker comprises a In one preferred embodiment, a linker in a compound of the present invention comprises (or is) group, for example the linker comprises (or is) group, such as a group selected from: .In one preferred embodiment, a linker in a compound of the present invention . In certain embodiments, a linker in a compound of the present invention comprises (or is) a group, for example a linker in a compound of the present invention comprises (or is) a group selected from In certain very preferred embodiments, the linker is

[0268] In further embodiments, the linker is In another preferred embodiment, a linker in a compound of the present invention . In one preferred embodiment, a linker in a compound of the present inventioncomprises (or is) group, for example comprises (or is) a group selected from: , wherein preferably theester part of such a group is attached to a lysine side chain (for example attached to the NH2of the lysine side chain) of terminal or non-terminal lysine of a [N-terminal portion] or [C-terminal portion] of a CD16a binding polypeptide of the invention. For example, in embodiments where the linker is attached to the [N-terminal portion] of a CD16a binding polypeptide, and the N-terminal portion has the sequence X1X2X3X4X5, the linker is attached at the side chain of position X1of the [N-terminal portion] wherein X1 is lysine, or at the side chain of position X4 of the [N-terminal portion] wherein X4 is lysine; and especially at the side chain of position X4 of the [N- terminal portion] wherein X4is lysine. For example, in where the linker is attached to the [C-terminal portion] of a CD16a binding polypeptide, and the C-terminal portionhas the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, the linker is attached atthe side chain of position X58of the [C-terminal portion] wherein X58is lysine, or at the side chain of position X50 of the [C-terminal portion] wherein X50 is lysine; and especially at the side chain of position X50 of the [C-terminal portion] wherein X50 is lysine. In certain preferred embodiments, a linker in a compound of the present invention comprises two or more groups (for example, two, three, four, five or more groups) selected from the group consisting of triazole (for example 1,4-triazole, and in particular , wherein y is 1 to 10 (for example 1 to 5), wherein y is 1 to 10 (for example 1 to 5), . wherein n is 1 to 30 (for example 1 to 24, 1 to 12, 1 to 10, 1 to8, or 2 to 8 (and especially 2, 3, 4, 8, 12 or 24), and especially 2, 3, 4 or 8).In embodiments wherein a linker connects together two functional portions of thepolypeptides of the invention, preferably the linker comprises a triazole (for example one or two triazoles (preferably one triazole), for example one or two 1,4-subtituedtriazole and in particular one or two groups selected from the group consisting of ,

[0269] .In certain embodiments (for example, embodiments wherein a linker connectstogether two functional portions of the polypeptides of the invention), the linker comprises one or more group selected from the group consisting of triazole (forexample a 1,4-subtitued triazole) , wherein n is 1 to 30 (forexample 1 to 24, 1 to 12, 1 to 10, 1 to 8, or 2 to 8 (and especially 2, 3, 4, 8, 12 or 24), and especially 2, 3, 4, 8, 16 or 24). For example, the linker comprises (or is) the following group:

[0270] 1 to 12, 1 to 10, 1 to 8, or 2 to 8 (and especially 2, 3, 4, 8, 12 or 24, and very especially 8 or 24).In certain embodiments (for example, embodiments wherein a linker connectstogether two functional portions of the polypeptides of the invention), the linker comprises (or is) the following group: .In certain embodiments (for example, embodiments wherein a linker connectstogether two functional portions of the polypeptides of the invention), the linker comprises one or more group selected from dibenzoazacyclooctane (for example, , , , , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 4, 6 or 8). In certain embodiments the linker comprises (or is) a dibenzoazacyclooctane group. In certain embodiments the linker comprises adibenzoazacyclooctane and , wherein n is 1 to 30 (for example 1 to24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 4, 6 or 8). In such embodiments, preferably the linker comprises (or is) the following group: , ,

[0271]

[0272] , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 4, 6 or 8; and more especially 8). In certain embodiments, a linker in a compound of the present invention (for example, a linker as defined above) additionally comprises a group selected from the group For example, in embodiments wherein a linker connects together three or morefunctional portions of the polypeptides of the invention, preferably a linker in a compound of the present invention (for example, a linker as defined above)additionally comprises a group selected from the group consisting In certain embodiments (for example embodiments wherein a linker connects togetherthree or more functional portions of the polypeptides of the invention), preferably the linker comprises one or more groups selected from triazole (for example one or two (preferably two)triazoles, for example one or two 1,4-subtitued triazoles), and optionally further comprises one or more , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4). In such , (for example such embodiment, preferably the linker comprises two or more triazoles, and , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3or 4); and optionally group.In certain very preferred embodiments (for example embodiments wherein a linkerconnects together three or more (for example three) functional portions of the polypeptides of the invention), preferably the linker comprises one or more (forexample one, two or three, preferably two) , one or more (forexample one, two or three, preferably three) , wherein n is 1 to 30(for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4, and very especially n is 2 or 3 (for example 3)), and one for more (for example one) . In such embodiment, when more than one is present, preferably each n is the same (e.g. each n is 3).In certain very preferred embodiments (for example embodiments wherein a linkerconnects together three or more (for example three) functional portions of the polypeptides of the invention), preferably the linker comprises one or more (forexample one, two or three, preferably two) wherein y is 1 to 10(for example 1 to 5, preferably 4 or 5 and very especially 4), one or more (for exampleone, two or three, preferably three) , wherein n is 1 to 30 (forexample 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4, and very especially n is 2 or 3 (for example 3)), and one for more (for example one) . such embodiment, when more than one is present, preferably each n is the same (e.g. each n is 2). In such embodiment, when more than one present, preferably each y is the same (e.g. each y is 2). In embodiments wherein a linker connects together three or more functional portions (for example 3 functional portions (for example one CD16a binding polypeptide, onebinding partner recognising PD-L1, and an additional functional portion (e.g. aBCMA binding portion))), preferably the linker comprises (or consists of) the

[0273] following group:

[0274] . In another embodiment wherein a linker connects together three or more functionalportions (for example 3 functional portions (for example one CD16a bindingpolypeptide, one binding partner recognising PD-L1, and an additional functionalportion (e.g. a BCMA binding portion))) in a polypeptide of the invention, preferablythe linker comprises (or consists of) the following group:

[0275] . In another embodiment wherein a linker connects together three or more functional portions (for example 3 functional portions (for example one CD16a binding polypeptide, one binding partner recognising PD-L1, and an additional functional portion (e.g. a BCMA binding portion))) in a polypeptide of the invention, preferably the linker comprises (or consists of) the following group: In another embodiment wherein a linker connects together three or more functional portions (for example 3 functional portions (for example one CD16a binding polypeptide, one binding partner recognising PD-L1, and an additional functional portion (e.g. a BCMA binding portion))) in a polypeptide of the invention, preferably the linker comprises (or consists of) the following group:

[0276] . In another embodiment wherein a linker connects together three or more functional portions (for example 3 functional portions (for example one CD16a binding polypeptide, one binding partner recognising PD-L1, and an additional functionalportion (e.g. a BCMA binding portion))) in a polypeptide of the invention, preferablythe linker comprises (or consists of) the following group:

[0277]

[0278] . In another embodiment (for example an embodiment wherein a linker connectstogether three or more functional portions), the linker comprises one or more groupselected from triazole (for example one or two triazoles, for example a 1,4-traizole) and , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4). In such embodiments the linker may optionallyadditionally comprise group, a group). In one preferred embodiment, thelinker comprises one or two triazole (for example one or two triazoles 1,4-traizole) , wherein n is 1 to 30 (for example 1 to 24, 1 to 16, 1 to 12, 1 to8, or 2 to 8, and especially group. For example, thelinker comprises (or is) the following group: wherein q is 1 to 30 (preferably q is 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 8) and each n is independently 1 to 30 (preferably n is 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4). For example the linker comprises (or is) . one embodiment, the linker comprises (or is) the following group: wherein q is 1 to 30 (preferably q is 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 8) and each n is independently 1 to 30 (preferably n is 1 to 24, 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4). For example the linker comprises (or is) In another embodiment (for example an embodiment wherein a linker connects together three or more functional portions), the linker comprises one or more groupselected from the group consisting of dibenzoazacyclooctane and ,wherein n is 1 to 30 (for example 1 to 24, 1 to 12, 1 to 10, 1 to 8, or 2 to 8, and especially 2, 3 or 4). In such embodiments the linker may optionally additionally ). For example, the linker comprises one, two or more dibenzoazacyclooctane groups (for example two dibenzoazacyclooctane, or three dibenzoazacyclooctane groups), and optionally further comprises one or more , wherein n is 1 to 30 (for example 1 to 24, 1 to 12, 1 to 10, 1 to 8, or 2 to 8, and especially 2, 3 or 4). In such embodiments the linker may optionally additionally comprises

[0279] comprises (or is) the following

[0280] .In embodiments of the present invention comprising a further additional functionalportion in addition to the additional binding moiety which is a binding partnerrecognising a protein in the B7 family and which is a polypeptide, peptide or small molecule, the CD16a-binding polypeptide(s) and further additional functionalportion(s) in a CD16a-binding polypeptide or a CD16a-binding oligomer of thepresent invention may be separated by a linker. For example, each additional functional portion and CD16a-binding polypeptide in a CD16a-binding polypeptide orCD16a-binding oligomer of the present invention may be separated by a linker.Preferably, the linker is a linker as defined herein. In embodiments of the presentinvention comprising two or more further additional functional portions, theadditional functional portions may be separated by a linker. Preferably, the linker is alinker as defined herein.Where a CD16a-binding polypeptide or a CD16a-binding oligomer of the presentinvention comprises more than one linker (i.e. wherein there are at least two CD16a- binding polypeptides and at least one additional functional portion; or wherein there is at least one CD16a-binding polypeptides and at least two additional functionalportions), the linkers may be the same or may be different.Binding partner recognising an immune checkpoint proteinThe CD16a binding motifs in polypeptides of the invention are attached, for examplevia a linker as described hereinabove, to at least one additional functional portion, which comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule. For the avoidance of doubt, a CD16a binding motif in a CD16a binding polypeptide or a CD16a binding oligomer of the present invention may be directly attached to theat least one additional functional portion, which comprises an additional bindingmoiety which is a binding partner recognising a protein in the B7 family and which isa polypeptide, peptide or small molecule (i.e. not attached via a linker).A ‘functional portion’, as used herein, refers to a component or ‘moiety’ with a specific desired biological activity. A ‘peptide’, as used herein, refers to a compound consisting of 2 to approximately 50 amino acids joined together by peptide bonds, or a molecule designed to mimic such a compound (‘peptidomimetic’). Peptides may be macrocyclic (i.e. peptide structures bearing one or more rings and spanning multiple amino acid residues). Peptidomimetic compounds are small, protein-like chains that are typically produced by modification of an existing peptide, or by designing similar systems that mimic peptides. A ‘polypeptide’, as used herein, refers to a longer, continuous unbranched peptide chain. A ‘small molecule’, as used herein, refers to any non-peptide or non-polypeptide organic compound with a low molecular weight (typically 1,000 daltons or less).In an embodiment, the CD16a binding polypeptides as disclosed herein are attached,for example via a linker as described hereinabove, to at least one additional functional portion, which comprises an additional binding moiety which is a binding partner recognising PD-L1 and which is a polypeptide, peptide or small molecule. The CD16a binding oligomers as disclosed herein are attached, for example via a linker as described hereinabove, to at least one additional functional portion, which comprises an additional binding moiety which is a binding partner recognising PD-L1 and which is a polypeptide, peptide or small molecule. For the avoidance of doubt, a CD16a binding polypeptide or CD16a binding oligomer of the present invention may be directly attached to the at least one additionalfunctional portions, which comprises an additional binding moiety which is a bindingpartner recognising PD-L1 and which is a polypeptide, peptide or small molecule (i.e.not attached via a linker). Examples of peptide-based binding partners recognising PD-L1 suitable for use in aCD16a-binding polypeptide or CD16a-binding oligomer of the present inventioninclude macrocyclic peptides of the type disclosed in US 20140294898 A1, i.e. macrocyclic peptides containing 15 residues (e.g. peptide-57 / BMS-57), macrocyclic peptides containing 14 residues (e.g. peptide-71 / BMS-71), or macrocyclic peptides containing 13 residues (e.g. peptide-99 / BMS-99). For example, suitable peptide-basedbinding partners recognising PD-L1 may include BMS-986189, BMSpep-57, BMS-57, BMS-71, BMS-99 and BMS-91.Examples of polypeptide-based binding partners recognising PD-L1 suitable for usein a CD16a-binding polypeptide or CD16a-binding oligomer of the present inventioninclude PD-L1-specific antibodies, aptamers, affimers, affibodies, avimers, DARPins,knottins, monobodies, nanobodies, or ADAPTs (Albumin-binding domain DerivedAffinity ProTeins). For example, the binding partner recognising PD-L1 is an aptamer. Aptamers recognising PD-L1 suitable for use in a CD16a-bindingpolypeptide or CD16a-binding oligomer of the present invention are for exampledescribed in Bertrand et al. 2023 (J. Med. Chem. 2023, 66, 16, 10878–10888), inparticular the aptamers known as aptPD-L1, BSA apt, PL1 and N5. For example, the binding partner recognising PD-L1 is an affibody, i.e. for example a polypeptide comprising at least one motif that binds to PD-L1, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1a]-[Separating portion]-[Helix 2a]-[C-terminal portion],the PD-L1-binding motif being the portion [Helix 1a ]-[Separating portion]-[Helix 2a]. Affibody-based binding partners recognising PD-L1 suitable for use in a CD16a-binding polypeptide or CD16a-binding oligomer of the present invention include those disclosed in patent applicationno. WO 2017 / 072280 A1. Preferably, the binding partner recognizing PD-L1 is apolypeptide (affibody) comprising a PD-L1 binding module having the sequence ERNX4AAX7EIL X11LPNLX16X17X18QX20 WAFIWX26LX28D wherein, independently from each other, X4 is selected from A, D, E, F, H, I, K, L, N, Q, R, S, T, V and Y; X7 is selected from A, E, F, H, N, Q, S, T, V, W and Y; X11is selected from A, D, E, F, H, K, L, N, Q, R, S, T, V, W and Y; X16is selected from N and T; X17 is selected from A, H, K, N, Q, R and S; X18 is selected from A, D, E, G, H, K, L, N, Q, R, S, T, V and Y; X20is selected from H, I, K, L, N, Q, R, T, V and Y; X26 is selected from K and S; and X28 is selected from A, D and E. Preferably, the binding partner recognizing PD-L1 is a polypeptide (affibody) having the sequence AEAKYAKERNAAAYEILYLPNLTNAQKWAFIWKLDDDPSQSSELLSEAKKLN DSQAPKVD Examples of small molecule-based binding partners recognising PD-L1 suitable foruse in a CD16a-binding polypeptide or CD16a-binding oligomers of the presentinvention include BMS-8, BMS-37, BMS-200, BMS-202, BMS-1165, BMS-1166,BMS-1016, BMS-2007, BMS-40210 and BMS-1001. For example, the bindingpartner recognising PD-L1 is selected from the group consisting of BMS-8, BMS-200,BMS-202, BMS-1165, BMS-1166, BMS-1016, BMS-2007, BMS-40210 and BMS-1001. Preferably, the binding partner recognising PD-L1 is the small moleculeinhibitor BMS-1001. In addition to the PD-L1 binding partners described hereinabove, further PD-L1 inhibitors have also been produced. These inhibitors include molecules that may disrupt the PD-1 / PD-L1 checkpoint interaction by other means, for example by inducing dimerization and subsequent internalisation of PD-L1. Such dimerization / internalisation-inducing molecules may also be used in a CD16a-binding polypeptide or CD16a-binding oligomer of the present invention and include for example Incyte-001, Incyte-011, INCB086550, and ARB-272572. Other PD-L1 inhibitors may disrupt the PD-1 / PD-L1 interaction indirectly, for example thecompounds CA-170, CA-327 and Aurigene-1.In another embodiment, the CD16a binding polypeptides as disclosed herein are attached, for example via a linker as described hereinabove, to at least one additional functional portion, which comprises an additional binding moiety which is a bindingpartner recognising B7-H3 and which is a polypeptide, peptide or small molecule.The CD16a binding oligomers as disclosed herein are attached, for example via a linker as described hereinabove, to at least one additional functional portion, which comprises an additional binding moiety which is a binding partner recognising B7-H3 and which is a polypeptide, peptide or small molecule. For the avoidance of doubt, a CD16a binding polypeptide or CD16a binding oligomer of the present invention may be directly attached to the at least one additionalfunctional portions, which comprises an additional binding moiety which is a bindingpartner recognising B7-H3 and which is a polypeptide, peptide or small molecule (i.e.not attached via a linker). Examples of polypeptide-based binding partners recognising B7-H3 suitable for use in a CD16a-binding polypeptide or CD16a binding oligomer of the present invention include B7-H3 -specific antibodies, aptamers, affimers, affibodies, avimers, DARPins, knottins, monobodies, nanobodies, [other classes]. For example, the binding partner recognising B7-H3 is an affibody, i.e. for example a polypeptide comprising at least one motif that binds to B7-H3, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1c]-[Separating portion]-[Helix 2c]-[C-terminal portion],the B7-H3-binding motif being the portion[Helix 1c ]-[Separating portion]-[Helix 2c]. Affibody-based binding partnersrecognising B7-H3 suitable for use in a CD16a-binding polypeptide or CD16a- binding oligomer of the present invention include those disclosed in patent applicationno. US2021 / 0340257 A1 and Oroujeni et al, Nuclear Medicine and Biology 2023124-125:108384. Preferably, the binding partner recognizing B7-H3 is a polypeptide (affibody) comprising the sequence: AEAKYAKEKX1X2AX3X4EIX5WLPNLTHGQIMAFIAALND where X1 is selected from I or V; X2is selected from F, I, A, H; X3is selected from L, V; X4is selected from G or S; X5is selected from Y or I.For example, the polypeptide may comprise the sequenceAEAKYAKEKIAALSEIIWLPNLTHGQIMAFIAALND [SEQ ID NO. 290]; inparticular, the polypeptide may comprise the sequence: AEAKY AKEKI AALSEIIWLP NLTHG QIMAF IAALN DDPSQ SSELL SEAKK LNDSQ [SEQ ID NO:291].Alternatively, the polypeptide may comprise the sequence: AEAKF AKEKI NALGEIIWLP NLTYD QIKAF IAKLN DDPSQ SSELL SEAKK LSESQ [SEQ ID NO:.292]; or the polypeptide may comprise the sequence: AEAKF AKEKI KALSE IIWLPNLTYG QIKAF IAKLN DDPSQ SSELL SEAKK LSESQ [SEQ ID NO. 293].Additional functional portions CD16a binding polypeptides as disclosed herein may be attached, for example via alinker as described hereinabove, to one or more further additional functional portions.CD16a binding oligomers as disclosed herein may be attached, for example via a linker as described hereinabove, to one or more additional functional portions. Therefore, in an embodiment, the at least one CD16a binding polypeptide (or CD16a binding oligomer) is attached to one or more further additional functional portions, optionally via a linker as described herein. For the avoidance of doubt, a CD16a binding polypeptide or CD16a binding oligomer of the present invention may be directly attached to one or more additional functional portions (i.e. not attached via a linker). A ‘functional portion’, as used herein, refers to a component or ‘moiety’ with a specific desired biological activity. The one or more additional component(s) (i.e. the one or more additional functional portion) may for example be a signalling molecule. Examples of suitable signalling molecules include immune signalling molecules such as cytokines, for example IL-15 and derivatives thereof. The one or more additional component(s) (i.e. the one or more additional functional portion) may be one or more additional binding moiety(ies), for example one or morebinding partner(s) recognising a cell surface protein or antigen, for example animmune cell surface protein or a cell surface tumour antigen (also referred to as acancer cell surface antigen). Cell surface tumour antigens may for example be tumour-associated antigens or tumour-specific antigens. Examples of additional components (i.e. additional functional portions) includeadditional binding moieties that are binding partners recognising B-cell maturationantigen (BCMA), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4),Programmed cell death protein 1 (PD-1), disintegrin and metalloprotease 17 (ADAM17), SLAM family member 7 (SLAMF7), Epithelial Cell Adhesion Molecule (EPCAM), Epidermal growth factor receptor (EGFR / ErbB-1), Epidermal growth factor receptor variant 3(EGFRvIII),erb-b2 tyrosine kinase 2 (ERBB2 / HER2 / CD340), prostate-specific membrane antigen (PSMA), Claudin8.2 (CLDN18.2), delta like protein 3 (DLL3), mucin 16 (MUC16), mucin 17 (MUC17), mucin 1 (MUC1), Trophoblast glycoprotein (TPBG / 5T4 / WAIF1), V-set domain- containing T-cell activation inhibitor 1 (B7-H4 / VTCN1 / B7x / B7S1), cluster of differentiate 20 (CD20), B-Lymphocyte Surface Antigen B4 (CD19), Sialic Acid- Binding Ig-Like Lectin 2 (CD22), TNF receptor superfamily member 8 (CD30),Natural cytotoxicity triggering receptor 1 (NKp46), or NKG2D. Examples ofadditional components (i.e. additional functional portions) include additional bindingmoieties that are binding partners recognising a cell surface tumour antigen or cancercell surface target selected from the group consisting of BCMA, ADAM17, SLAMF7,EPCAM, EGFR / ErbB-1, EGFRvIII, ERBB2 / HER2 / CD340, PSMA, CLDN18.2, DLL3, MUC16, MUC17, MUC1, TPBG / 5T4 / WAIF1 and B7-H4 / VTCN1 / B7x / B7S1. Examples of additional components (i.e. additional functional portions) include additional binding moieties that are binding partners recognising an immune cellsurface protein or immune cell surface target selected from the group consisting ofCTLA-4, PD-1, NKp46, NKG2D CD20, CD19, CD22 and CD30. Examples ofadditional components (i.e. additional functional portions) include additional bindingmoieties that are binding partners recognising a cell surface tumour antigen or cancercell surface target expressed in haematological malignancies, for example BCMA,CD20, CD19, CD22 or CD30. (For the avoidance of doubt, such examples ofadditional binding moieties, for example binding partners recognising cell surfaceproteins or antigens, are non-limiting and are specified here by way of illustration).The additional binding moiety as referred to in this context is not a CD16a binding polypeptide of the present invention.In one embodiment, a CD16a binding polypeptide or CD16a-binding oligomer of thepresent invention is attached to one or more further additional functional portion (forexample one or more additional binding moiety(ies) and / or signalling molecule),optionally via a linker as described above. For example, the at least one CD16abinding polypeptide or CD16a-binding oligomer is attached to one, two, three, four ormore further additional functional portions (for example one, two, three, four or moreadditional binding moieties and / or signalling molecules). In certain embodiments, atleast one CD16a binding polypeptide or CD16a-binding oligomer is attached to one ortwo additional functional portions (for example one or two additional bindingmoieties or signalling molecules). In certain embodiments, at least one CD16abinding polypeptide or CD16a-binding oligomer is attached to one additionalfunctional portion (for example one additional binding moiety or signalling molecule). In certain preferred embodiments, an additional function portion is a signalling molecule. A signalling molecule, for example an immune signalling molecule such asa cytokine, for example IL-15 or derivatives thereof, may be attached at the N-terminal end or the C-terminal end of a CD16a-binding polypeptide or a CD16a-binding oligomer, optionally via a linker as described above. One or more signalling molecule(s) may, alternatively, be attached between two CD16a-binding polypeptides in a CD16a-binding oligomer, optionally separated by one or more linking sequences as described above. Preferably, the signalling molecule(s) may be attached at the N-terminal end or the C-terminal end of a CD16a-binding polypeptide or a CD16a-binding oligomer, optionally via a linker as described above. Preferably, the signallingmolecule(s) may be attached at the N-terminal end of a CD16a-binding polypeptide or a CD16a-binding oligomer, optionally via a linker as described above. In certain preferred embodiments, an additional function portion is an additional binding moiety. For example, an additional function portion is an additional binding moiety that is a binding partner recognising one of the following: CTLA-4, PD-1, BCMA, ADAM17, SLAMF7, EPCAM, EGFR / ErbB-1, EGFRvIII, ERBB2 / HER2 / CD340, PSMA, CLDN18.2, DLL3, MUC16, MUC17, MUC1,TPBG / 5T4 / WAIF1, B7-H4 / VTCN1 / B7x / B7S1, CD20, CD19, CD22 or CD30. Forexample, an additional function portion is an additional binding moiety that is specific for one of the following: CTLA-4, PD-1, BCMA, ADAM17, SLAMF7, EPCAM, EGFR / ErbB-1, EGFRvIII, ERBB2 / HER2 / CD340, PSMA, CLDN18.2, DLL3, MUC16, MUC17, MUC1, TPBG / 5T4 / WAIF1, B7-H4 / VTCN1 / B7x / B7S1, CD20, CD19, CD22 or CD30. In certain preferred embodiments, an additional binding moiety is specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA). In certain preferred embodiments, an additional binding moiety is specific for animmune cell surface target (for example a NK cell target, for example NKp46,NKG2D, etc).An additional binding moiety, for example a binding partner recognising the cellsurface tumour antigen BCMA, may be attached at the N-terminal end or the C-terminal end of a CD16a-binding polypeptide or a CD16a-binding oligomer,optionally via a linker as described above. The one or more additional bindingmoiety(ies) may, alternatively, be attached between two CD16a-binding polypeptidesin a CD16a-binding oligomer, optionally separated by one or more linking sequencesas described above. Preferably, the additional binding moiety(ies), for example abinding partner recognising the cell surface tumour antigen BCMA, may be attached at the N-terminal end or the C-terminal end of a CD16a-binding polypeptide or aCD16a-binding oligomer, optionally via a linker as described above. Morepreferably, the additional binding moiety(ies), for example a binding partner recognising the cell surface tumour antigen BCMA, may be attached at the N-terminal end of a CD16a-binding polypeptide or a CD16a-binding oligomer, optionally via a linker as described above. The present inventors have surprisingly found that a ‘dual engager’ polypeptidecomprising a CD16a binding polypeptide or a CD16a binding oligomer as disclosedherein can retain its CD16a binding ability when fused to an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule. Furthermore, CD16a binding polypeptide of the invention also retains its CD16a binding ability when it is attached to a moietytargeting the myeloma antigen BCMA. Such a polypeptide comprising a CD16abinding polypeptide as disclosed herein fused to a BCMA binding moiety is also surprisingly capable of activating NK cells in the presence of BCMA-expressing tumour cells. For example, the additional binding moiety which is a binding partner recognising thecell surface tumour antigen BCMA may be an hBCMA-binding polypeptide whichcomprises at least one motif that binds to hBCMA, wherein said hBCMA-binding polypeptide comprises the following structure: [N-terminal portion]-[Helix 1b]-[Separating portion]-[Helix 2b]-[C-terminal portion] the hBCMA binding motif being the portion [Helix 1b]-[Separating portion]- [Helix 2b]. Such a binding moiety may be one wherein: i) Helix 1b comprises the sequence X9X10X11ADX14EIX17X18and Helix 2b comprises the sequence FX25QKWAFX31RX33LX35, wherein, independently from each other, X9 and X10 are any naturally occurring amino acid; X11is E, F, H, Q, T or Y; X14is any naturally occurring amino acid; X17 is A, E, Q, S, T or V; X18is any naturally occurring amino acid; X25 is F or Y; X31 is I, M, or V; X33 is K or S; X35is I, L, M, or V; or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue. In one preferred embodiment, the CD16a-binding polypeptide or CD16a-binding oligomer of the present invention further comprises one or more further additional functional portions, for example at least one, at least two, or at least three or at least four further additional functional portions. For example, in particular embodiments, CD16a-binding polypeptide or CD16a-binding oligomer of the present inventionfurther comprises 1, 2, 3, 4 or 5 further additional functional portions. In especiallypreferred embodiments, the CD16a-binding polypeptide or CD16a-binding oligomer of the present invention further comprises one, two or three additional functional portions, and most preferably two.In one embodiment, a CD16a-binding polypeptide or CD16a-binding oligomercomprising an additional binding moiety of the present invention has a furtheradditional binding moiety separated from the CD16a-binding polypeptide or the CD16a-binding oligomer by a linker. A linker may be any linker definedhereinabove. For example, a linker selected from flexible amino acid linkers, rigidamino acid linkers, cleavable amino acid linkers and non-amino acid linkers.Preferably, a linker for a CD16a-binding polypeptide or CD16a-binding oligomercomprising a further additional binding moiety comprises or has a sequence of 1 to 50(for example 1 to 25, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25) naturally occurring amino acids; and preferably 1 to20 (for example 1, 5, 10, 15, or 20; and more preferably 1 to 15) naturally occurringamino acids, for example selected from the group consisting of G, S and T (preferablyG and S).In one preferred embodiment, a linker for CD16a-binding polypeptide or CD16a-binding oligomer comprising an additional binding moiety of the present invention is G or comprises or has sequence GGGSG, GGGGS, GGSGG, GSGGG and / or SGGGG; for example the linker is G or comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG or GGGSGGGGSGGGGSGGGGSGGGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS, GGGGSGGGGSGGGGSGGGGS, GGSGG, GGSGGGGSGG, GGSGGGGSGGGGSGG, GGSGGGGSGGGGSGGGGSGGGGSGG, GSGGG, GSGGGGSGGG, GSGGGGSGGGGSGGG, GSGGGGSGGGGSGGGGSGGG, SGGGG, SGGGGSGGGG, SGGGGSGGGGSGGGG, or SGGGGSGGGGSGGGGSGGGG.In one preferred embodiment, a linker for a CD16a-binding oligomer of the presentinvention is G or comprises or has sequence GGGSG; for example, the linkercomprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG or GGGSGGGGSGGGGSGGGGSG. In another embodiment, a linker for a CD16a-binding oligomer of the present invention comprises or has sequence GGGGS; forexample the linker comprises or has the sequence GGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS GGGGSGGGGSGGGGSGGGGS.In a further preferred embodiment, the linker in such a CD16a-binding polypeptide orCD16a-binding oligomer is a synthetic linker as described herein above.Alternatively, in one embodiment, a CD16a-binding polypeptide or CD16a-bindingoligomer comprising an additional binding moiety of the present invention has an additional binding moiety that is not separated from the CD16a-binding polypeptideor the CD16a-binding oligomer by a linker (i.e. the CD16a-binding polypeptide orCD16a-binding oligomer is directly attached to an additional binding moiety).In one preferred embodiment, a CD16a-binding polypeptide or CD16a-bindingoligomer comprising an additional binding moiety of the present invention does notcomprise a linker. In one preferred embodiment, the CD16a-binding polypeptide orCD16a-binding oligomer is directly attached to an additional binding moiety.In certain embodiments, a CD16a-binding polypeptide of the present inventioncomprising an additional functional portion comprises the following structure:[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[linker]-[additional functional portion]; [additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion] [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[linker]-[additional functional portion]- [additional functionalportion]; [additional functional portion]-[additional functional portion]-[linker]-[N- terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]; or [additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion]-[linker]-[additional functional portion]; wherein, when more than one additional functional portion is present, each additionalfunctional may be the same, or may be different.In such embodiments, the linker preferably comprises or has a sequence of 1 to 25(for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24 or 25) naturally occurring amino acids; and preferably 1 to 20 (for example 1, 5, 10, 15, or 20; and more preferably 1 to 15) naturally occurring amino acids, forexample selected from the group consisting of G, S and T (preferably G and S). Forexample, the linker is G or comprises or has sequence GGGSG, GGGGS, GGSGG,GSGGG and / or SGGGG; for example the linker is G or comprises or has the sequence GGGSG, GGGSGGGGSG, GGGSGGGGSGGGGSG, GGGSGGGGSGGGGSGGGGSG, GGGGS, GGGGSGGGGS, GGGGSGGGGSGGGGS, GGGGSGGGGSGGGGSGGGGS, GGSGG, GGSGGGGSGG, GGSGGGGSGGGGSGG, GGSGGGGSGGGGSGGGGSGGGGSGG, GSGGG, GSGGGGSGGG, GSGGGGSGGGGSGGG, GSGGGGSGGGGSGGGGSGGG, SGGGG, SGGGGSGGGG, SGGGGSGGGGSGGGG, or SGGGGSGGGGSGGGGSGGGG.In a further preferred embodiment, the linker in such a CD16a-binding polypeptide orCD16a-binding oligomer is a synthetic linker as described herein above.Alternatively, the linker may be absent, i.e. the CD16a-binding polypeptide orCD16a-binding oligomer comprises the following structure:[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[additional functional portion]; [additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion] [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[additional functional portion]- [additional functional portion];[additional functional portion]-[additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]; or [additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[additional functional portion].In such embodiments, more preferably the CD16a-binding polypeptide comprises thefollowing structure: [additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion] [additional functional portion]-[additional functional portion]-[linker]-[N- terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]; or [additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion]-[linker]-[additional functional portion] (or comprises the following structure[additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion] [additional functional portion]-[additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]; or [additional functional portion]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]-[additional functional portion]). In such embodiments, preferably each additional functional portion is an additional binding moiety specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA). Most preferably each additional functional portion is an additional binding moiety specific for BCMA,Even more preferably, the CD16a-binding polypeptide comprises the followingstructure: [additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]- [Separating portion]-[Helix 2]-[C-terminal portion]; or [additional functional portion]-[additional functional portion]-[linker]-[N- terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]. In such embodiments, preferably each additional functional portion is an additional binding moiety specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA). Most preferably each additional functional portion is an additional binding moiety specific for BCMA, In one very especially preferred embodiment of the invention the CD16a-binding polypeptide comprises the following structure: [additional functional portion]-[additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]. In such embodiments, preferably each additional functional portion is an additional binding moiety specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA). Most preferably each additional functional portion is an additional binding moiety specific for BCMA. Optionally, in such embodiments, the linker may be absent. In another very especially preferred embodiment of the invention the CD16a-binding polypeptide consists of the following structure: [additional functional portion]-[additional functional portion]-[linker]-[N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion]. In such embodiments, preferably each additional functional portion is an additional binding moiety specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA). Most preferably each additional functionalportion is an additional binding moiety specific for BCMA. Optionally, in suchembodiments, the linker may be absent.In the above embodiments defining the structure of the CD16a-binding polypeptide orCD16a-binding oligomer comprising a further additional functional portion, eachfurther additional functional portion may be anyone described herein. For example,each additional functional portion may be independently selected from an additional binding moiety (for example an additional binding moiety specific for a cancer cell surface target, for example a myeloma cell surface antigen, for example BCMA, or an immune cell target, for example a NK cell target); and an immune signalling molecule, for example a cytokine, for example IL-15 orderivatives thereof. For example, each further additional functional portion may be independently selected from: an additional binding moiety specific for a cancer cell surface target (for example a myeloma cell surface antigen, for example BCMA); an additional binding moiety specific for an immune cell target (for example a NK cell target); andan immune signalling molecule, for example a cytokine, for example IL-15 orderivatives thereof.For example, each further additional functional portion may be independently selectedfrom: an additional binding moiety specific for BCMA; an additional binding moiety specific for a NK cell target; andan immune signalling molecule, for example a cytokine, for example IL-15 orderivatives thereof. For example, each further additional functional portion may be independently selected from: an additional binding moiety specific for BCMA; and an additional binding moiety specific for a NK cell target; andan a cytokine, for example IL-15 or derivatives thereof.For example, each further additional functional portion may be independently selected from: an additional binding moiety specific for BCMA; and an additional binding moiety specific for a NK cell target; andIL-15 or derivatives thereof.In one preferred embodiment, each additional functional portion may be independently selected from: an additional binding moiety specific for BCMA; and an additional binding moiety specific for a NK cell target; andan a cytokine, for example IL-15 or derivatives thereof. In one preferred embodiment, each additional functional portion may be independently selected from: an additional binding moiety specific for BCMA; and an additional binding moiety specific for a NK cell target. In one preferred embodiment, each additional functional portion is an additional binding moiety specific for BCMA.In the above embodiments defining the structure of the CD16a-binding polypeptide orCD16a-binding oligomer comprising an additional functional portion, each additional function portion may be an additional binding moiety (for example an additional binding moiety specific for a cancer cell surface target, for example a myeloma cell surface antigen, for example BCMA). For example, each additional function portion may be an additional binding moiety for BCMA.In a preferred embodiment, an additional binding moiety for BCMA is a hBCMA-binding polypeptide which comprises at least one motif that binds to hBCMA, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion] the hBCMA binding motif being the portion [Helix 1]-[Separating portion]-[Helix 2].For example, it is a hBCMA-binding polypeptide as defined in the PCT Applicationfiled in the name of Oncopeptides Innovation 1 AB on 31 May 2023 claiming priority to GB Application No.2208027.9 and to GB Application No.2214718.5. The contents of that PCT application are herein incorporated by reference. In particular, the hBCMA-binding polypeptide is one wherein: i) Helix 1 comprises the sequence X9X10X11ADX14EIX17X18 and Helix 2 comprises the sequence FX25QKWAFX31RX33LX35, wherein, independently from each other, a) X9 and X10 are any naturally occurring amino acid; X11 is E, F, H, Q, T or Y; X14 is any naturally occurring amino acid; X17 is A, E, Q, S, T or V; X18 is any naturally occurring amino acid; X25is F or Y; X31is I, M, or V; X33is K or S; X35 is I, L, M, or V; or ii) Helix 1 and Helix 2 are defined as in i), wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xnresidues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xnare replaced by an alternative residue. For example, the hBCMA-binding polypeptide is one with hBCMA binding efficacy is at least 1% of the sequence VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAE AKKLNDAQAPK [SEQ ID 226]. In a very preferred embodiment, the hBCMA-binding polypeptide is the polypeptide of SEQ ID 226. In another very preferred embodiment, the hBCMA-binding polypeptide is a polypeptide comprising (or having) a sequence selected from the group consisting ofSEQ ID Nos: 1027 to 1035 of Figure 31 and a sequence of Table A below, or aderivative thereof (for example wherein from 1 to 5 (for example 1, 2 or 3 amino acid residues) may be replaced by an alternative residue, for example a different naturally occurring amino acid or a different unnatural amino acid; or a different naturally occurring amino acid excluding methionine or a different unnatural amino acid). Table A: hBCMA-binding polypeptide sequences

[0281] In another very preferred embodiment, the hBCMA-binding polypeptide is a polypeptide comprising a sequence selected from the group consisting of SEQ IDNos: 1027 to 1035 of Figure 32 and a sequence of Table B below, or a derivativethereof wherein from 1 to 5 (for example 1, 2 or 3 amino acid residues) may be replaced by an alternative residue, for example a different naturally occurring amino acid or a different unnatural amino acid; or a different naturally occurring amino acid excluding methionine or a different unnatural amino acid. Table B: hBCMA-binding motif sequences The invention further provides a hBCMA-binding polypeptide which comprises atleast one motif that binds to hBCMA, wherein said polypeptide comprises thefollowing structure: [N-terminal portion B]-[Helix B1]-[Separating portion B]-[Helix B2]-[C-terminal portion B],the hBCMA-binding motif being the portion [Helix B1]-[Separating portion B]-[Helix 2B], wherein the sequence of the CD-16a-binding motif is selected from SEQ ID Nos: 1036 to 1042.The invention further provides a hBCMA-binding polypeptide which comprises atleast one motif that binds to hBCMA, wherein said polypeptide comprises thefollowing structure: [N-terminal portion B]-[Helix B1]-[Separating portion B]-[Helix B2]-[C-terminal portion B],the hBCMA-binding motif being the portion [Helix B1]-[Separating portion B]-[Helix B2], wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID NOs: 1027 to 1035.Such polypeptides comprising a sequence selected from SEQ ID Nos: 1036 to 1042and SEQ ID NOs: 1027 to 1035 can form a part of a hBCMA-binding oligomer. Theymay also be a part of a binder comprising one or more additional functional portions as described elsewhere herein.According to a preferred embodiment of the present invention, there are provided thefollowing additional CD16a- binding polypeptides.

[0282] The multi-specific engagers of the invention may demonstrate “bi-paratopic binding”or a “bi-paratopic effect” This is demonstrated where two domains of a CD16a- binding polypeptide according to the present invention both contribute to CD16a- binding. The present invention, therefore, further provides dimeric engagers comprising two CD16a domains which demonstrate bi-paratopic binding.Preferably, the engager demonstrating the bi-paratopic binding comprises hCD16aheterodimeric binding variants His6-A10-A11-Cys [SEQ ID No: 81] and His6-A11-A10-Cys [SEQ ID No:82],In a another preferred embodiment, there is provided hCD16a heterodimeric bi-paratopic binding variants A10-A11-His6 [SEQ ID No: 83] and A11-A10-His6 [SEQID No: 84]CD16a binder-drug conjugatesAlternatively, or additionally, a CD16a binding polypeptide or CD16a -bindingoligomer as disclosed herein may be attached to a therapeutic agent to form a CD16abinder-drug conjugate. Therefore, in an embodiment, the at least one CD16a binding polypeptide or CD16a-binding oligomer is typically covalently attached to one or more therapeutic agent(s), optionally via a linker or linkers as described above. Non- limiting examples of such therapeutic agents include cytotoxic drugs, for example mitomycin C, desmethyltopotecan, SN-38, MMAE, MMAF, doxorubicin, pyrrolobenzodiazepine, amanitin, maytansinoids (for example maytansinoid DM1 or maytansinoid DM4), or duostatins (for example duostatin 5.2). For the avoidance of doubt, during the generation of a CD16a binder-drug conjugate according to the invention, the one or more therapeutic agent(s) (for example MMAF) is necessarily modified by the reaction between the functional group at the point of attachment (for example –NH, –OH or –SH (for example in a Cys)) and any attachment groups or linkers used. The skilled person will therefore understand thatthe therapeutic agent in a CD16a binder-drug conjugate (for example a CD16a binder-MMAF conjugate) comprises such a modification. Polypeptide-oligonucleotide conjugatesAlternatively, or additionally, a CD16a binding polypeptide or CD16a -bindingoligomer as disclosed herein may be attached to an oligonucleotide. Theoligonucleotide can be a single- or double-stranded DNA, RNA or PNA molecule.The function of the oligonucleotide could be as a messenger, antisence, interference or guide to be used for gene expression regulation or specific gene editing purposes. Polypeptide production The polypeptides of the invention can be manufactured using methods known in theart. For example, they can be prepared by chemical synthesis methods or byrecombinant protein production techniques in, for example, bacterial, yeast, insect,fungal, plant or mammalian cells. Polypeptides of the invention may also be fused, via recombinant or chemical synthesis techniques as described above, to a different molecule with therapeutic potential, for example an immunoglobulin with therapeutic potential. Derivatives, Salts and Solvates The present invention provides polypeptides and oligomers, derivatives of such polypeptides and oligomers, and salts or solvates of such polypeptides and oligomers, and derivatives thereof. Whilst in some embodiments, the invention relates to a polypeptide or oligomer of theinvention and is not a derivative, in other embodiments the invention relates to aderivative of a polypeptide and oligomer of the invention. The derivative may for example comprise one or more derivatisations selected from amidation and / or acylation.In certain embodiments, it is preferred that the polypeptides and oligomers of theinvention may be amidated at their C-terminal. Such a modification is very commonin nature with approximately half of naturally occurring peptides being susceptible toamidation at their C-terminal. The present invention encompasses all of the genericand specific sequences disclosed herein, including in the sequence listing and drawings and examples, in both amidated and non-amidated forms, the amidation, where present being especially preferred on the C-terminal of the peptide sequence.In certain embodiments, it is preferred that the polypeptides and oligomers of theinvention may be acylated at their N-terminal. The present invention encompasses allof the generic and specific sequences disclosed herein, including in the sequence listing and drawings and examples, in both acylated and non-acylated forms, the acetylation, where present being especially preferred on the N-terminal of the peptide sequence. Salt forms of the polypeptides and oligomers of the invention, and of derivatives ofsuch polypeptides and oligomers, also form part of the invention. In someembodiments the salt is a salt of a polypeptide or oligomer of the invention. In other embodiments the salt is a salt of a derivative of polypeptide or oligomer of the invention. Salts of polypeptide or oligomer of the invention include those which are pharmaceutically acceptable, i.e. which are suitable for use in medicine. However, salts having non-pharmaceutically acceptable counterions are also within the scope of the present invention, for example, for use as intermediates in the preparation of the polypeptide or oligomer of the invention. Suitable salts according to the invention include those formed with organic or inorganic acids or bases. Pharmaceutically acceptable acid addition salts include those formed with hydrochloric, hydrobromic, sulphuric, nitric, citric, tartaric, acetic, phosphoric, lactic, pyruvic, acetic, trifluoroacetic, succinic, perchloric, fumaric, maleic, glycolic, salicylic, oxaloacetic, methanesulfonic, ethanesulfonic, p- toluenesulfonic, formic, benzoic, malonic, naphthalene-2-sulfonic, benzenesulfonic, and isethionic acids. Other acids such as oxalic acid may be useful as intermediates in obtaining the compounds of the invention in final form. Pharmaceutically acceptable salts with bases include ammonium salts, alkali metal salts, for example potassium and sodium salts, alkaline earth metal salts, for example calcium and magnesium salts, and salts with organic bases, for example dicyclohexylamine and N-methyl-D-glucomine. More preferably, the salt of a polypeptide, oligomer or derivative of the present invention is the hydrochloride salt, trifluoroacetate salt or acetate salt (i.e. the additionsalt formed from hydrochloric acid, trifluoroacetic acid or acetic acid). Morepreferably, the salt is the acetate salt. Those skilled in the art of organic and / or medicinal chemistry will appreciate that many organic compounds can form complexes with solvents in which they are reacted or from which they are precipitated or crystallized. Such complexes are known as "solvates". For example, a complex with water is known as a "hydrate". The invention also encompasses solvates of the polypeptides and oligomers of the present invention, solvates of derivatives of the polypeptides and oligomers of the presentinvention, and solvates of salts of the derivatives.Those skilled in the art of organic and / or medicinal chemistry will also appreciate than many organic compounds can exist in different forms, including as amorphous material and / or in one or more crystalline forms. Different physical forms of organic compounds are known as polymorphs. The invention also encompasses all such different physical forms of the polypeptides and derivatives of the invention, as well as different physical forms of their derivatives and salts.Modulation of polypeptide propertiesThe pharmacokinetic properties of the polypeptides of the invention can be modulatedby methods known in the art. For example, they can be linked to a moiety extendingthe plasma half-life, such as a polyethylene glycol polymer, an unstructuredpolypeptide (such as XTEN or PAS), or an FcRn binding ligand such as serumalbumin or the Fc domain of an immunoglobulin. FormulationsPolypeptides according to the invention (for example, a CD16a-binding polypeptideor CD16a-binding oligomer of the present invention, or a CD16a binder-drugconjugate) may be present in a formulation and particularly in a pharmaceuticalformulation. In certain embodiments, the invention provides a nucleic acid molecule encoding theCD16a-binding polypeptide or CD16a-binding oligomer of the invention. A nucleicacid molecule encoding the CD16a-binding polypeptide or CD16a-binding oligomerof the invention may be used as a medicament, for example may be used for thetreatment of cancer. The nucleic acid molecule may, for example, be a DNA or an RNA molecule, for example a mRNA molecule. Nucleic acid molecules according to the invention may be present in a formulation and particularly in a pharmaceutical formulation. As such, the present invention further provides a formulation andparticularly in a pharmaceutical formulation of a nucleic acid molecule (for example,a DNA or RNA, and in particular a mRNA molecule) encoding the CD16a-binding polypeptide or CD16a-binding oligomer of the invention.Pharmaceutical formulations include for example those suitable for oral, parenteral(including subcutaneous, intradermal, intraosseous infusion, intramuscular,intravascular (bolus or infusion), and intramedullary), or intraperitonealadministration, although the most suitable route may depend upon, for example, thecondition and disorder of the subject under treatment. In one embodiment of the invention, a CD16a binding polypeptide or CD16a binding oligomer (in particular a CD16a binder-drug conjugate) or nucleic acids (for example DNA or RNA molecules of the present invention, for example an mRNA molecule) according to the invention is administered as a pharmaceutical formulation suitable for oral or parenteral (including subcutaneous, intradermal, intraosseous infusion, intramuscular, intravascular (bolus or infusion), and intramedullary) administration. Pharmaceutical formulations suitable for oral administration may be presented as discrete units such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous liquid or a non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. Peptides of the invention may also be presented as a bolus, electuary or paste. Various pharmaceutically acceptable carriers and their formulation are described in standard formulation treatises, e.g., Remington's Pharmaceutical Sciences by E. W. Martin. See also Wang, Y. J. and Hanson, M. A., Journal of Parenteral Science and Technology, Technical Report No.10, Supp.42:2S, 1988. Formulations for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agentsand thickening agents. Preferably, the formulations may be presented in unit dosage or divided dosage containers, for example sealed ampoules and vials. The formulation may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example saline, a physiologically acceptable solution or water-for-injection, immediately prior to use. Extemporaneous injection and infusion solutions and suspensions may be prepared from sterile powders, granules or other dry composition. Exemplary compositions for parenteral administration include injectable solutions or suspensions which can contain, for example, suitable non-toxic, parenterally acceptable diluents or solvents, such as mannitol, 1,3-butanediol, water, Ringer’s solution, an isotonic sodium chloride solution, or other suitable dispersing or wetting and suspending agents,including synthetic mono- or diglycerides, and fatty acids, including oleic acid, orCremaphor.Dosage regimensA CD16a-binding polypeptide or CD16a binding oligomer (in particular a CD16abinder-drug conjugate) of the invention, and a pharmaceutical formulation comprisingsuch a polypeptide, oligomer or binder-drug conjugate, or nucleic acid molecules of the invention (for example, DNA or RNA molecules of the present invention, for example a mRNA molecule of the present invention), and pharmaceutical formulations comprising those nucleic acid molecules, find use in the treatment and / or prophylaxis of cancer, for example multiple myeloma.The amount of a CD16a-binding polypeptide or CD16a binding oligomer (inparticular, a CD16a binder-drug conjugate) or nucleic acid molecule, required toachieve a therapeutic effect will vary with the particular route of administration andthe characteristics of the subject under treatment, for example the species, age, weight, sex, medical conditions, the particular disease and its severity, and other relevant medical and physical factors. An ordinarily skilled physician can readily determine and administer the effective amount of the CD16a-binding polypeptide,CD16a oligomer, CD16a binder-drug conjugate and / or composition comprising thesame, or nucleic acid molecule and / or composition comprising the same, required for treatment and / or prophylaxis of cancer.A CD16a-binding polypeptide, CD16a binding oligomer (in particular, a CD16abinder-drug conjugate) or nucleic acid molecule of the invention, or a pharmaceutical formulation thereof, may for example be administered daily, weekly, every second, third or fourth week or even as a high single dose depending on the subject and severity of the cancer to be treated.A CD16a-binding polypeptide, CD16a binding oligomer (in particular, a CD16abinder-drug conjugate) or nucleic acid molecule of the invention, or a pharmaceutical formulation thereof, may for example be administered as a parenteral or oral dosage. Parenteral administration includes intravenous (into a vein, for example a central or a peripheral vein, bolus or infusion), intra-arterial (into an artery, for example a central or a peripheral artery), intraosseous infusion (into the bone marrow), intra-muscular (into muscle), intradermal (into the dermis), and subcutaneous (under the skin)administration. In one preferred embodiment, the dosage of the present invention isadministered intravenously or intra-arterially, and more preferably by intravenous infusion (for example central intravenous infusion or peripheral intravenous infusion). In another preferred embodiment, the dosage of the present invention is administered by subcutaneous injection. As such, pharmaceutical formulations especially useful for the present invention are those suitable for intravenous administration, more especially intravenous infusion, or subcutaneous administration.A CD16a-binding polypeptide, CD16a binding oligomer (in particular, a CD16abinder-drug conjugate) or nucleic acid molecule of the invention, and pharmaceuticalformulations thereof, may be administered as part of a treatment cycle. In a treatmentcycle, said polypeptides may be administered on day 1 of the cycle, wherein the cyclelasts X days, with no further administration of the CD16a-binding polypeptides orCD16a-binding oligomers of the invention for the next X-1 days. X may be, forexample, from 1 to 42, for example from 2 to 14 days. Alternatively, the CD16a-binding polypeptides or CD16a-binding oligomers may be administered as a splitdose, for example on for example on days 1 and 2 of the cycle. The cycle may be repeated one or several times depending on the category, class or stage of the cancer to be treated. For example, the cycle may be repeated from 1 to100 times, for example from 2 to 50 times, for example 8 to 40 times, for example 8or 16 times. For example, the CD16a-binding polypeptides or CD16a-bindingoligomers or nucleic acid molecules of the invention may be administered for 8repeats of a 7 day cycle, followed by 16 repeats of a 14 day cycle, optionally followedby further repeats of a 28 day cycle. An ordinarily skilled physician or clinician can readily determine the number of cycles of CD16a-binding polypeptide (for example CD16a binder-drug conjugate) required to prevent, counter or arrest the progress of the cancer. Combination treatments Whilst a CD16a-binding polypeptide or CD16a binding oligomer (in particular a CD16a binder-drug conjugate) or nucleic acid molecules disclosed herein may be used as the sole active ingredient in the present invention, it is also possible for it to be used in combination with one or more further therapeutic agent(s), and the use of such combinations provides one embodiment of the invention. Such further therapeutic agents may be agents useful in the treatment and / or prophylaxis of cancer, or other pharmaceutically active materials. Such agents are known in the art. Non-limiting examples of further therapeutic agents for use in the present inventionmay include proteasome inhibitors (PIs) (for example carfilzomib, bortezomib orixazomib), immunomodulatory agents (IMiDs) (for example lenalidomide,thalidomide or pomalidomide), alkylators (for example cyclophosphamide,melphalan, bendamustine or melflufen), anthracyclines (for example doxorubicin),steroids (for example dexamethasone, prednisone or prednisolone), BCL-2 inhibitors(for example venetoclax), histone deacetylase (HDAC) inhibitors (for example panobinostat), anti-CD38 agents (for example daratumumab or isatuximab), immunecheckpoint inhibitors (for example a CTLA-4 inhibitor, or a PD-1 inhibitor), orADAM17 inhibitors. For example, further therapeutic agents may be selected fromproteasome inhibitors (for example carfilzomib or bortezomib), immunomodulatory agents (for example lenalidomide or thalidomide), alkylators (for example melphalan or melfufen), steroids (for example dexamethasone or prednisone), anti-CD38 agents (for example daratumumab), an immune checkpoint inhibitor (for example a CTLA-4 inhibitor, or a PD-1 inhibitor), and an ADAM17 inhibitor. The one or more further therapeutic agent(s) may be used simultaneously, sequentially or separately with / from the administration of the dosage of CD16a binding polypeptides, CD16a binding oligomers, CD16a binder-drug conjugates, or nucleic acid molecules of the invention. The individual components of such combinations can be administered separately at different times during the course of therapy or concurrently in divided or single combination forms. In an embodiment of the invention, the one or more further therapeutic agent(s) are selected from a PI, an IMiD, and a steroid. For example, the one or more further therapeutic agents are a PI (for example bortezomib or carfilzomib), an IMiD (for example lenalidomide, thalidomide and pomalidomide), and a steroid (for example,prednisone, prednisolone and dexamethasone). Preferably, the one or moretherapeutic agents are bortezomib, thalidomide, and dexamethasone. In an embodiment of the invention, the one or more further therapeutic agent(s) are selected from a PI, an alkylator, and a steroid. For example, the one or more further therapeutic agents are a PI (for example bortezomib or carfilzomib), an alkylator (forexample cyclophosphamide, melphalan, melflufen or bendamustine), and a steroid(for example, prednisone, prednisolone and dexamethasone). Preferably, the one or more therapeutic agents are bortezomib, melphalan, melflufen, and prednisone. In an embodiment of the invention, the one or more further therapeutic agent(s) are selected from a PI and a steroid. For example, the one or more therapeutic agents are a PI (for example bortezomib or carfilzomib), and a steroid (for example, prednisone,prednisolone and dexamethasone). Preferably, the PI is bortezomib and the steroid isdexamethasone. In an embodiment of the invention, the one or more further therapeutic agent(s) are selected from an IMiD and a steroid. For example, the one or more therapeutic agents are an IMiD (for example lenalidomide, thalidomide and pomalidomide), and a steroid (for example, prednisone, prednisolone and dexamethasone). Preferably, the IMiD is lenalidomide and the steroid is dexamethasone. In another embodiment of the invention, the one or more therapeutic agent(s) may be selected from an NK cell-based or T cell-based therapy. Alternatively, a CD16a-binding polypeptide or CD16a binding oligomer (in particulara CD16a binder-drug conjugate) or nucleic acid molecule according to the inventionmay be combined with a therapeutic procedure such as a stem cell transplantation procedure, for example an autologous stem cell transplant or an allogenic stem cell transplant. Therefore, in an embodiment of the invention, a CD16a-binding polypeptide disclosed herein may be combined with an autologous stem cell transplantation procedure. In another embodiment of the invention, a CD16a-bindingpolypeptide disclosed herein may be combined with an allogenic stem celltransplantation procedure. The simultaneous, sequential or separate administration of one or more further therapeutic agent (s) or therapeutic procedure with the CD16a binding polypeptides, CD16a binding oligomers, CD16a binder-drug conjugates or nucleic acid molecules of the invention further enhances their effectiveness in the treatment and / or prophylaxis of cancer. Kits The present invention provides a kit comprising a CD16a-binding polypeptide, CD16a binding oligomer (in particular a CD16a binder-drug conjugate) or nucleic acid molecule as disclosed herein, and one or more further therapeutic agents that are useful in the treatment and / or prophylaxis of cancer. Non-limiting examples of further therapeutic agents for use in a kit of the present invention may include proteasome inhibitors (PIs) (for example carfilzomib, bortezomib or ixazomib), immunomodulatory agents (IMiDs) (for example lenalidomide, thalidomide or pomalidomide), alkylators (for examplecyclophosphamide, melphalan, melflufen or bendamustine), anthracyclines (forexample doxorubicin), steroids (for example dexamethasone, prednisone or prednisolone), BCL-2 inhibitors (for example venetoclax), histone deacetylase (HDAC) inhibitors (for example panobinostat), anti-CD38 agents (for example daratumumab or isatuximab), immune checkpoint inhibitors (for example a CTLA-4inhibitor, or a PD-1 inhibitor), or ADAM17 inhibitors. The one or more furthertherapeutic agents may, for example, be selected from proteasome inhibitors (forexample carfilzomib or bortezomib), immunomodulatory agents (for examplelenalidomide or thalidomide), alkylators (for example melphalan or melflufen),steroids (for example dexamethasone or prednisone), anti-CD38 agents (for example daratumumab), an immune checkpoint inhibitor (for example a CTLA-4 inhibitor, or a PD-1 inhibitor), and an ADAM17 inhibitor. In one embodiment of the invention, the kit of the present invention finds use in thetreatment and / or prophylaxis of cancer.For the avoidance of doubt, a CD16a-binding polypeptide, CD16a binding oligomer (in particular a CD16a binder-drug conjugate) or nucleic acid molecule as disclosed herein is present in a kit according to the present invention in a form and quantity suitable for use according to the present invention. Suitable pharmaceutical formulations are described herein. The skilled person can readily determine a quantity of the CD16a binding polypeptide or oligomer (for example in the form of a CD16a binder-drug conjugate) or nucleic acid molecule as disclosed herein suitable for the use according to the present invention. CancersCD16a-binding polypeptides or CD16a-binding oligomers of the present invention,(in particular CD16a binder-drug conjugates) or nucleic acid molecules of the present invention, as well as pharmaceutical formulations or kits of the present invention comprising said CD16a-binding polypeptides, CD16a binding oligomers, CD16abinder-drug conjugates or nucleic acid molecules, find use in medicine, for examplein the treatment and / or prophylaxis of cancer in a subject. Non-limiting examples ofcancers include: solid cancers, such as bladder cancer, breast cancer, colorectalcancer, CNS cancers, endometrial cancer, kidney cancer, liver cancer, lung cancer, skin cancer, ovarian pancreatic cancer, prostate cancer, or thyroid cancer; and blood cancers, such as leukaemias (for example acute myeloid leukaemia, acute lymphoblastic leukaemia, chronic myeloid leukaemia, or chronic lymphocytic leukaemia), lymphomas (for example Hodgkin lymphoma, non-Hodgkin lymphoma,cutaneous T-cell lymphoma, small lymphocytic lymphoma, and other high-grade B-cell lymphomas), or plasma cell neoplasms and myelomas (for example, MGUS,plasmacytoma, smouldering myeloma, multiple myeloma, light chain myeloma, or non-secretory myeloma). Preferably, CD16a-binding polypeptides or CD16a binding oligomers of the present invention (in particular CD16a binder-drug conjugates) or nucleic acid molecules of the present invention, as well as pharmaceutical formulations or kits of the present invention comprising said CD16a-binding polypeptides, oligomers, binder-drugconjugates or nucleic acid molecules, find use in the treatment and / or prophylaxis of blood cancers, such as leukaemias (for example acute myeloid leukaemia, acute lymphoblastic leukaemia, chronic myeloid leukaemia, or chronic lymphocytic leukaemia), lymphomas (for example Hodgkin lymphoma, non-Hodgkin lymphoma, cutaneous T-cell lymphoma, small lymphocytic lymphoma, and other high-grade B- cell lymphomas), or plasma cell neoplasms and myelomas (for example, MGUS, plasmacytoma, smouldering myeloma, multiple myeloma, light chain myeloma, ornon-secretory myeloma). Preferably, CD16a-binding polypeptides or CD16a-bindingoligomers of the present invention, as well as pharmaceutical formulations or kits ofthe present invention comprising said CD16a-binding polypeptides or CD16a-bindingoligomers, find use in the treatment and / or prophylaxis of myelomas (for example,MGUS, plasmacytoma, smouldering myeloma, multiple myeloma, light chainmyeloma, or non-secretory myeloma). Most preferably, CD16a-binding polypeptides,CD16a-binding oligomers, CD16a binder-drug conjugates or nucleic acid molecules of the present invention, as well as pharmaceutical formulations or kits of the present invention comprising said CD16a-binding polypeptides, CD16a-binding oligomers, CD16a binder-drug conjugates or nucleic acid molecules, find use in the treatment and / or prophylaxis of multiple myeloma. In certain embodiments the CD16a-binding polypeptides or CD16a binding oligomers of the present invention (in particular CD16a binder-drug conjugates) or nucleic acid molecules of the present invention, as well as pharmaceutical formulations or kits of the present invention comprising said CD16a-binding polypeptides, oligomers, binder-drug conjugates or nucleic acid molecules, find use as anti-cancer immunotherapeutics; for example anti-cancer immunotherapeutics for use in the treatment of cancers, and in particular blood cancers, for example a blood cancer as described herein, and in particular multiple myeloma. Alternatively, or additionally, polypeptides or nucleic acid molecules of the present invention, as well as pharmaceutical formulations or kits of the present invention comprising a hBCMA-binding polypeptide, hBCMA-binding oligomer, hBCMAbinder-drug conjugate or nucleic acid molecules, may also find use in the treatmentand / or prophylaxis of an autoimmune disorder in a subject. Non-limiting examples of autoimmune disorders include Addison’s disease, coeliac disease, dermatomyositis, Graves disease, Hashimoto’s thyroiditis, multiple sclerosis and optic neuritis, myasthenia gravis, pernicious anemia, reactive arthritis or rheumatoid arthritis, Sjögren’s syndrome, systemic lupus erythematosus, or Type I diabetes, in particular autoimmune disorders in which hBCMA signalling is implicated, for example, systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and optic neuritis and Sjögren’s syndrome. Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

[0283] Examples The following Examples illustrate the invention. In this regard, we refer to published PCT application PCT / EP2023 / 064624 (WO 2023 / 232911, Oncopeptides Innovation 1 AB). Examples 1 to 17 of PCT / EP2023 / 064624 disclose CD16a-binding polypeptides, which may be used as a portion of the compounds according to thepresent invention with an additional functional portion described herein. The bindingability of those polypeptides, alone or when combined with other functional portions, is also demonstrated. The Examples 1 to 17 of PCT / EP2023 / 064624 are summarised below:-Preparative Example 1 of PCT / EP2023 / 064624: Selection of binders to hCD16aby phage display using a phage library In this Example, human hCD16a was used as the target in phage display selectionsusing a phage-based affibody library. Individual clones obtained after four selectioncycles were assayed for binding to hCD16a in a monoclonal phage-ELISA (enzyme- linked immunosorbent assay) and ELISA-positive clones were DNA sequenced. ResultsThree unique clones had been enriched during the selections (as shown in Figure 1b).The amino acid sequences of these three CD16a-binding polypeptides, A10, A11 andH09 are listed in Table 1 below and in the sequence listing as SEQ IDs 1, 74 and 75.Table 1 also lists the sequences of certain other peptides closely based on those thatare also disclosed in published patent application PCT / EP2023 / 064624, with thecorresponding SEQ ID No: references.Table 1 Table 1 shows the sequences of certain peptides of the present disclosure with their allocated SEQ ID NOs.Biological Example 2 of PCT / EP2023 / 064624:Initial binding studies using surface plasmon resonance In this Example, CD16a-binding polypeptides corresponding to SEQ ID 1, 74 and 75 were subcloned, expressed, purified as His6-affibody-ABDWT fusion proteins [SEQ IDNos: 76 to-78] and initially analysed by surface plasmon resonance for binding toCD16a. Results Analyses of the equilibrium responses for the interactions allowed for a determination of the dissociation equilibrium constant (KD) for the interactions. The fusion proteincontaining the A10 CD16a-binding polypeptide [SEQ ID NO: 76] showed to bindboth the F158 and V158 allotypes with similar affinity, with KD´s of approximately 100 and 99 nM, respectively. In contrast, fusion proteins containing either the H09 or A11 CD16a-binding polypeptides [SEQ ID No:s 77 and 78], both showed to bindF158 allotype with higher affinity than the V158 allotype. Dissociation equilibriumconstants for the interactions were calculated to be 2.8 µM (A11 / V158), 8.3 µM (A11 / F158), 621 nM (H09 / F158) and 4.9 µM (H09 / V158).Biological Example 3 of PCT / EP2023 / 064624:Binning studies of the hCD16a binding variants using surface plasmon resonance In this Example, SPR experiments were performed to investigate if the three identified anti-CD16 affibodies bound to distinct or shared / overlapping epitopes on hCD16a. Results The results of the epitope binning assay showed that a first binding of the fusion protein His6-A10-ABDWT to hCD16a did not block the binding to hCD16a of subsequently injected fusion proteins His6-H09-ABDWTor His6-A11-ABDWT, containing the H09 and A11 CD16a-binding polypeptides, respectively, indicating non-overlapping epitopes on hCD16a for variant A10 and either of the variants H09 and A11 (Figure 4). From the results obtained in a similar experimental set-up using His6-H09-ABDWTand His6-A11-ABDWTfusion proteins, it could be concluded that the variants H09 and A11 bind to overlapping epitopes (Figure 4). The mutualepitope binning results were not dependent on the V158 or F158 allotypes of hCD16a.Biological Example 4 of PCT / EP2023 / 064624:Binding studies of monomeric, heterodimeric and homodimeric CD16a-binding polypeptide constructs using surface plasmon resonance In this Example, SPR experiments were performed to compare hCD16a binding properties of a set of monomeric and heterodimeric CD16a-binding polypeptide constructs. Results Expression vectors for a set of monomeric and heterodimeric CD16a-bindingpolypeptides were constructed. Four constructs, His6-A10-Cys, His6-A11-Cys, His6-A10-A11-Cys and His6-A11-A10-Cys [SEQ ID Nos: 79-82], corresponded to eithermonomeric or heterodimeric CD16a-binding polypeptide constructs equipped with both an N-terminal His6 tag and a C-terminal cysteine residue. Two heterodimericconstructs, A10-A11-His6 and A11-A10-His6 [SEQ ID Nos: 83 to 84] and one dualengager construct composed of a BCMA-binding polypeptide fused to a homodimeric A10-A10 CD16a-binding polypeptide arm, anti-BCMA-A10-A10-His6 [SEQ ID No: 86], were designed to contain only a C-terminal His6 tag. The A10 and A11 CD16a-binding polypeptides bind to non-overlapping epitopes on hCD16a, the results strongly suggesting that both the His6-A10-A11-Cys and His6- A11-A10-Cys proteins are capable of binding to hCD16a via a bi-paratopic effect.The results in Figure 7 shows that in this assay format the binding responses to bothhCD16a ligands, A10-A11-His6 [SEQ ID No: 83] and A11-A10-His6 [SEQ ID No:84], obtained reflect a stronger binding (slower off-rate kinetics) than observed for any of the individual and monomeric A10 or A11 counterparts as analysed in thesame assay format in Example 2 (Figure 3). This further indicates that a bi-paratopicbinding effect to hCD16a can be obtained from combining the A10 and A11 variants into heterodimeric constructs. Furthermore, as the H09 CD16a-binding polypeptidewas shown to bind to an epitope not overlapping with that of the A10 CD16a-binding polypeptide (Example 3), heterodimeric variants based on combinations of theA10 / H09 variants could, based on the results in this Example, also be expected toshow bi-paratopic binding to hCD16a, which is also demonstrated in Example 5. In addition, the results show that compared with proteins containing a single momomeric A10 CD16a-binding polypeptide moiety (Figure 3), the protein analysed here containing two tandemly linked A10 CD16a-binding polypeptide moieties display a significantly stronger apparent affinity for both the hCD16a variants Taken together, the hCD16a binding analyses of this set of monomeric, heterodimeric and homodimeric constructs based on the CD16a-binding polypeptides described in Example 4 of PCT / EP2023 / 064624, incorporated herein by reference, show that these can be freely combined in new constructs to result in a variety of novel hCD16a- binding proteins with different binding characteristics, including bi-paratopic andbivalent binding. The choice of CD16a-binding polypeptides and their relative order(N-term-to-C term) enables the overall binding properties to be varied. In the set ofconstructs analysed in this Example, a common 15 amino acid linker composed ofthree tandemly arranged GGGSG motifs (SEQ ID No:145) was used to link homodimeric and heteodimeric combinations. Additional hCD16a binding constructs based on alternative polypeptide or chemical linkers (including a direct linkage; i.e. no linker or indirect linkage via a linker), and inclusion of more than two identical or different CD16a-binding polypeptide moieties are also encompassed by the present invention using methods known in the art (Figures 5a, 5b and 6).Biological Example 5 of PCT / EP2023 / 064624:Assessment of a BCMA × hCD16a dual engager construct using surface plasmon resonance In this Example, SPR experiments were performed to analyse the bi-specific binding characteristics of a tri-partite fusion protein containing an hBCMA binding polypeptide (herein referred to as 1-E6, with sequence VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAEAKKLNDAQAPK, SEQ ID No:226) fused to a hCD16a binding arm consisting of aheterodimeric H09-A10 CD16a-binding polypeptide combination. Results Thes resulting sensorgrams show that the hBCMA x hCD16a dual engager construct is capable of simultaneous binding to both the immobilized hBCMA-rFc ligand and the subsequently injected hCD16a variants. The slow off-rate kinetics seen aftercompleted injections (phase IV in Figure 10b) indicates that also the H09-A10affibody combination is capable of bi-paratopic binding to hCD16a, as previouslydemonstrated for the A10-A11 and A11-A10 combinations (Example 4). Also, asexpected from the results obtained in Example 2, a slower hCD16a dissociation rate(Figure 10b, phase IV) was seen for the interaction with the hCD16a F158 variant than for the hCD16a V158 variant as the H09 affibody variant had been demonstrated to bind stronger to the hCD16a F158 allotype (Example 2). Taken together, the results show that an affibody-based hCD16a binding arm, here composed of a heterodimeric H09-A10 affibody combination, can retain its hCD16a binding ability also when fused to another polypeptide unit that simultaneously is engaged in binding to a therapeutically relevant target, here exemplified by a genetically fused polypeptide binding to hBCMA which is a target of relevance inmultiple myeloma cancer (Figures 9, 10a, 10b, Example 2 and Example 4).Biological Example 6 of PCT / EP2023 / 064624:Anti-BCMA engagers induce immune cell activation in the presence of tumour cells Experiments were performed to evaluate the propensity of different anti-BCMA engagers to evoke an IFN^^response in cocultures of human PBMCs and the BCMA positive multiple myeloma cell line MM.1S. Anti-BCMA engager constructs containing a BCMA-binding polypeptide (herein termed 1-E6) genetically fused to a hCD16a binding arm composed of eithermonomeric A10 (SEQ ID No:88), homodimeric A10 (SEQ ID No:86), heterodimericH09-A10 (SEQ ID No:85) or heterodimeric A11-A10 (SEQ ID No:87) affibodieswere evaluated. Corresponding constructs harbouring a null non-BCMA-binding polypeptide with high sequence identity with the BCMA-binding polypeptide werealso evaluated. The SLAMF7 monoclonal antibody elotuzumab was used as apositive control and single cultures of PBMC and MM.1S served as negative controls. The dual engagers containing a BCMA-binding polypeptide all evoked an IFN^ response in cocultures of PBMC and MM.1S cells, which for all engagers was largerthan the response of the positive control elotuzumab (Figure 11). Dual engagerconstructs devoid of BCMA binding showed no or limited IFN^ response incocultures of PBMC and MM.1S cells. These experiments illustrate the BCMA dependent activation of PBMC against the BCMA positive MM.1S myeloma cell line induced by the anti-BCMA engagers described herein.Biological Example 7 of PCT / EP2023 / 064624:Assessment of secondary structure contents and thermal denaturation profiles of CD16a-binding polypeptides using circular dichroism In this Example, the three CD16a-binding polypeptides A10, H09 and A11 [SEQ IDNos: 1, 74 and 75] were subcloned, expressed, purified as polypeptide-His6 fusionproteins to assess the secondary structure contents and their thermal denaturation profiles by circular dichroism (CD) spectroscopy. Results Taken together, the results support that the three CD16a-binding polypeptides generated contain predominantly α-helical secondary structures and are capable of refolding following heat denaturation. Biological Example 8 of PCT / EP2023 / 064624: Alanine scan of the CD16a-binding clone A10 In this Example, an alanine scan of the polypeptide variant A10 [SEQ ID No:1] was performed to investigate the relative importance of the amino acid occupancies at the positions randomized during library construction for the binding interaction of A10 with CD16a. Results: Separate injections of the 14 alanine-substituted variants (polypeptide-YY-His6format), at a common concentration of 200 nM), over a sensor chip surface containing CD16a (F158) protein resulted in a series of sensorgrams from which the importance of the original amino acid in the anti-CD16a A10 polypeptide for the binding to CD16a could be deduced. The sensorgrams are shown in Figure 13. The substitution for alanine at positions 9, 11, 13, 14, 18, 27, 32 [SEQ ID Nos 2, 3, 4, 5, 6, 8 and 9] did not significantly affect the binding, as resulting sensorgrams resembled that obtained for the original A10 polypeptide with respect to response level and curve form. In contrast, alanine substitution at positions 10, 17, 24, 28 and 31 resulted in variants showing significantly lower binding responses. A few variants, H25A and M35A [SEQ ID Nos 7 and 10] were moderately affected by the alanine substitution.Analyses by circular dichroism spectrometry showed that all variants had profilescharacteristic for proteins with a high content of α helices, with clear minima at 221and 205 nm (see data in Figure 14). Thermal melting experiments showed that all but one variant (I31A) showed a retained thermal melting point of ca.50 °C (see data in Figure 15). Taken together, this indicated that the lower binding responses seen for some variants were not associated with a corresponding loss of overall structure, but rather that key residues for the interaction with CD16a had been addressed.Preparative Example 9 of PCT / EP2023 / 064624:Second-generation library construction, selection and phage ELISA In this Example, a second-generation library of the CD16a binding polypeptide A10 was constructed based on re-randomization of certain variable positions, and to various degrees. The library was used for the identification of second-generation variants of the CD16a binding A10 polypeptide but with a retained ability to bind CD16a with different strengths. The library was devoid of methionine. Individual and unique clones obtained after four phage display selection cycles and subsequent DNA sequencing were assayed for binding to CD16a in a monoclonal phage-ELISA. Results Positions in the A10 peptide identified as important for CD16a binding (Q10, R17,H24, F28 and I31) were randomized conservatively For these positions, trinucleotide codon mixes used for synthesis of the mutagenic oligonucleotides were biased to provide a 90 % likelihood for re-insertion of the amino acid found in the A10 peptide, leaving a 10 % likelihood for insertion of a different amino acid (any of the 20 natural amino acids, minus the A10 amino acid or methionine, cysteine, proline or glycine). For six positions (9, 13, 14, 18, 27 and 32), at which the original amino acid in the A10 peptide was not found to be critical for CD16a binding, trinucleotide codon mixes used for synthesis of the mutagenic oligonucleotides were biased to only provide a 10 % likelihood for re-insertion of the amino acid found in the A10 peptide, leaving a 90% likelihood for insertion of a different amino acid (any of the 20 natural amino acids, minus the A10 amino acid or methionine, cysteine, proline or glycine). For position 25, occupied by a histidine in the A10 peptide, the trinucleotide codon mix used for synthesis of the mutagenic oligonucleotides was biased to provide a 65 % likelihood for re-insertion of histidine, leaving a 35% likelihood for insertion of a different amino acid (any of the 20 natural amino acids, minus histidine, methionine, cysteine, proline or glycine). For position 33, occupied by a serine in the A10 peptide, the trinucleotide codon mix used for synthesis of the mutagenic oligonucleotides was biased to provide an 80 % likelihood for re-insertion of serine,leaving a 20% likelihood for insertion of lysine. For positions 11 and 35, bothoccupied by oxidation-prone methionines in the A10 peptide, the trinucleotide codon mix used for synthesis of the mutagenic oligonucleotides was biased to provide a 15 % likelihood for insertion of isoleucine, and an 85% likelihood for insertion of a different amino acid (any of the 20 natural amino acids, minus methionine, cysteine, proline or glycine). Selection for CD16a binding polypeptides from this library would thus have the potential to yield novel A10-related, CD16a binding polypeptides (denoted A10*) of different affinities. It also has the possibility to yield methionine-free CD16a binding polypeptides. Selections to CD16a (F158) target protein were performed by phage display asdescribed above (Material and methods – see Examples of PCT / EP2023 / 064624).Analysis of the selection outputs from the different selection tracks by monoclonal phage-ELISA and DNA sequencing resulted in the identification of 53 unique andELISA-positive clones Their sequences are shown in the Table in Figure 23 as SEQ ID Nos:11-63. Three further clones of interest (SEQ ID Nos:64-66) were also identified.Biological Example 10A of PCT / EP2023 / 064624:Expression, protein purification and SPR analysis of CD16a binding polypeptides identified in Example 9 ResultsThe genes encoding 53 of the polypeptides identified in Example 9 were re-clonedfor soluble expression as 1-E6-(GGGSG)3-A10*-YY-His6fusion proteins. The polypeptide herein named 1-E6 is an hBCMA binding polypeptide with the sequence VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAEAKKL NDAQAPK (SEQ ID No:226). A10* is used here to denote individual CD16a binding polypeptides identified in Example 9. The A10* sequences are the ones shown for SEQ ID Nos:11 to 63 in the table in Figure 23. Expression was performed at a cultivation scale of 2.5 ml and polypeptide purification was performed by IMAC. A Biacore 8K instrument was used to investigate the binding of the different 1-E6-(GGGSG)3-A10*-YY-His6 polypeptides. In the analysis, the polypeptide with SEQ ID No.1 was included, also produced as a fusion to the anti-BCMA binding polypeptide 1-E6. IMAC-purified fusion polypeptides were diluted to approximately 500 nM in PBS-T buffer and injected in parallel over sensor chip surfaces containing immobilized CD16a F158 or CD16a V158 fusion protein. The resulting sensorgrams demonstrated binding of all 53 injected analytes to the CD16a allotypes V158 and F158 and that the binding profiles to both allotypes were very similar for each analyte, as also observed for the polypeptide with SEQ ID No.1. The measured binding affinities (KD) for each of the polypeptides with CD16a binding sequence of SEQ ID Nos 11-63 are presented in the Table in Figure 23. It is seen that the binding to CD16a F158 or CD16a V158 fusion protein is similar in each case. Binding to CD16b (NA1 and NA2 forms) was also measured.Evaluation of further variants of A10 [SEQ ID Nos: 64-67] Constructs of Example 9 [SEQ ID Nos:64-66] alongside a further construct of interestwith SEQ ID No: 67 were synthesised and cloned into the NdeI XhoI sites of pET29for expression as 1-E6-(GGGSG)3-A10*-YY-His6 fusion proteins. Expression,isolation and characterisation can be found in Example 11 and generated constructsSEQ ID Nos: 98, 93, 97 and 100, respectively. Binding to CD16a F158 was studiedby SPR with the receptor as ligand on a CM-5 Biacore chip (4000 Ru). Engager constructs were diluted to 55 nM in HBS-EP buffer (Cytiva) for binding analysis. The resulting sensorgrams demonstrated binding of all 4 injected analytes.Biological Example 10B of PCT / EP2023 / 064624:Kinetic determination of a subset of 13 variants identified in Example 9 ResultsFor the subset of 13 variants as well as the fusion protein containing the polypeptidewith SEQ ID No.1, CD16a F158 and V158 binding analyses were performed using serial dilutions, allowing for a determination of association rate (on-rate) (M-1s-1) and dissociation rate (off-rate) (s-1) kinetic constants, as well as overall dissociationequilibrium constants, i.e. KD values (M). The results of binding with CD16a F158are shown in Figure 15b and in Table 2 below. Of particular note is the polypeptide denoted [SEQ ID No:51] which was determined to have a particularly high affinity (KD). A plotting of the respective on-rate (M-1s-1) and off-rate (s-1) kinetic constants (Figure 15c, and also shown in Table 2) showed that the 13 analysed variants displayed a large distribution in their association rate and dissociation rate constants.Interestingly, some variants with similar overall affinities (KD) (e.g. SEQ ID No:43and SEQ ID No:15) were found to have both different on-rate and off-rate kinetics, thus representing alternative binding properties resulting in a similar overall affinity.The variant with SEQ ID No:51 showed the highest affinity among the 13 analysedvariants, and it was seen to have relatively slow on-rate kinetics but also markedly slow off-rate kinetics, resulting in an overall high affinity. Table 2 Biological Example 11 of PCT / EP2023 / 064624:CD16a activation and NK cell mediated cell killing by hBCMA × hCD16a dual engager with hCD16a binding polypeptide identified as described in Example 9 above hBCMA × hCD16a dual engagers comprising hCD16a binding polypeptidesidentified as described in Example 9 above were expressed as soluble gene productsin E. coli (DE3) and, thereafter, characterized for their CD16a activation properties.Results The results are shown in Figure 16a and 16b. It is seen that the hBCMA × hCD16adual engagers (SEQ ID Nos:88-100, 121-126) demonstrated CD16 activation in theLucia Luciferase reporter assay in the presence of BCMA + MM.1S cells, whereas no detectable activation was seen in the absence of target cells (Figure 16a). Moreover, the engagers induced NK cell mediated killing of MM.1S cells (Figure 16b). Thus, a firm and target specific activation leading to NK mediated cell killing was seen for all engagers investigated. Table 3

[0284] Biological Example 12 of PCT / EP2023 / 064624:CD16a activation and NK cell mediated cell killing by hBCMA × hCD16a dual engagers with hCD16a binding polypeptide The hBCMA × hCD16a dual engagers comprising hCD16a binding polypeptides inExample engagers (SEQ ID Nos:127-129, as shown below) were expressed in E. coli(DE3) and thereafter characterized for their CD16a activation properties. The propensity of the hBCMA × hCD16a dual engagers to stimulate CD16a activation and to enhance NK cell mediated killing were assessed according to the protocols described in Biological Example 11. Table 4 Results The results are shown in Figure 17a and 17b. It is seen that the hBCMA × hCD16a dual engagers (Example engagers SEQ ID Nos:27-129) demonstrated CD16a activation in the Lucia Luciferase reporter assay in the presence of hBCMA + MM.1S cells, whereas no detectable activation was seen in the absence of target cells (Figure 17a). Moreover, the engagers induced NK cell mediated killing of MM.1S cells (Figure 17b). Thus, a firm and target specific activation leading to NK mediated cell killing was seen for the engagers investigated.Biological Example 13 of PCT / EP2023 / 064624:hCD16a activation by a hBCMA × hCD16a dual engager harbouring an IL-15 cytokine polypeptide: Results A hBCMA × hCD16a dual engager harbouring an IL-15 cytokine sequence (SEQ IDNo:101) was constructed and expressed as soluble gene products in E. coli (DE3).The CD16a activation response of the engager construct in the presence and absence of target MM.1s cells is shown in Figure 18. It is seen in the Figure that the affibody-based IL-15 containing dual engager can activate CD16a in a target specific manner. Table 5 Biological Example 14 of PCT / EP2023 / 064624:CD16a activation and NK cell mediated cell killing of hBCMA × hCD16a dual engager constructs with different domain order and linkers Compounds with different distances and ordering of targeting domains in dual engager constructs were prepared. The propensity of the hBCMA × hCD16a dual engagers to stimulate CD16a activation and to enhance NK cell mediated killing wereassessed according to the protocols described in Biological Example 11. The hCD16abinding was, in each case, the polypeptide with SEQ ID No.1. Table 6 Results hBCMA × hCD16a dual engager constructs containing one or two hBCMA-binding polypeptides genetically fused to a hCD16a binding arm composed of the polypeptide of SEQ ID No:1 and a C-terminal His6 tag were constructed and expressed as solublegene products in E. coli (DE3). Figure 19a shows the hCD16a activation responsesof the engager constructs in the presence or absence of target MM.1s cells. Moreover, the engagers induced NK cell mediated killing of MM.1S cells (Figure 19b). The results show that the affibody-based hCD16a binding arm, here composed of thepolypeptide of SEQ ID No:1, can activate hCD16a in a target specific manner whengenetically fused either N-terminally or C-terminally of a targeting polypeptide. In addition, the affibody-based hCD16a binding arm could also be fused between two other targeting polypeptide units. hCD16a activation was observed for engagers with linker length varying from 0 and 15 amino acids.Biological Example 15 of PCT / EP2023 / 064624:Assessment of domain boundaries in BCMA × hCD16a dual engager constructs using a Jurkat CD16a activation reporter assay and a NK mediated cell killing assayhBCMA × hCD16a dual binding constructs with truncations in both the N- and C-terminal of both the BCMA binding polypeptide and the CD16a binding A10 affibody were produced and evaluated in a hCD16a–mediated activation cell-based reporter assay and cell killing. This enabled the domain boundaries of the targeting domains in dual engager constructs to be assessed. Table 7

[0285] Design, construction, expression, and protein purification of hBCMA × hCD16a CD16a-binding polypeptide dual engager constructs.hBCMA × hCD16a dual binding constructs were designed for expression andpurification according to Biological Example 11. The heterodimeric hBCMA × hCD16a dual binding constructs that were prepared are listed above (SEQ ID Nos:111, 114-119). The propensity of the hBCMA × hCD16a dual engagers to stimulate CD16a activation and to enhance NK cell mediated killing were assessed according to the protocols described in Biological Example 11. Results hBCMA × hCD16a dual engager constructs containing one BCMA-binding polypeptide genetically fused to a hCD16a binding arm composed of the polypeptide of SEQ ID 1 and a C-terminal His6tag were constructed and expressed as solublegene products in E. coli (DE3). Figure 20a shows the CD16a activation responses ofthe engager constructs in the presence or absence of target MM.1s cells. Moreover, the engagers induced NK cell mediated killing of MM.1S cells (Figure 20b). The results show that the hCD16a binding arm, here composed of the polypeptide ofSEQ ID No:1 can be shortened and still retain hCD16a activation.Biological Example 16 of PCT / EP2023 / 064624:NK cell mediated multiple myeloma cell killing The ability of a hBCMA x hCD16a dual engager to promote NK cell mediated lysisand cell killing was assessed by a flow cytometry assay and an Incucyte® basedassay. The compounds investigated were: Table 8

[0286] Compounds were produced according to Biological Example 10A. Results The capacity of the dual engager Example Compound of SEQ ID 85 to induce lysis of MM.1s cells was examined. The results are shown in Figure 21a. Results are from one representative experiment (n=4). In a 24-hour killing assay, the Examplecompound with SEQ ID No:85 elicited rapid and superior lysis of MM.1s cells,compared to both daratumumab and the control null-variant anti-hBCMA-Null-H09-A10-His6. The bulk cytotoxic effect of the compound with SEQ ID No:85 was seenwithin the first 8 to 12 hours after the start of the co-culture. Finally, a flow cytometry-based killing assay was implemented to establish functional EC50 and EC90 values of the three constructs with SEQ ID Nos:85, 86 and 88. The frequency of dead target cells was calculated based on the staining of dead cell marker on target cells pre-incubated with cell trace violet (CTV). The results are shown in Figure 21b. Results are from two independent experiments (n=8), where spontaneous target cell death is subtracted. The plateau-level cytotoxicity was highestfor the compound with SEQ ID No:85 and lowest for the compound with SEQ IDNo:86, in agreement with the degranulation responses, which showed a higher fratricide effect for the latter construct. Compared with the compound with SEQ IDNo:88, plateau cytotoxicity for the compound with SEQ ID No:85 was reached at alower dose. EC50 values were 0.4 nM for SEQ ID No:85 and SEQ ID No:86, and 1.8 nM for SEQ ID No:8, while EC90values were 2.0, 3.8, and 14.7 nM, respectively. The data demonstrate that these dual engagers elicit potent responses.Biological Example 17 of PCT / EP2023 / 064624:Enhancement of NK cell mediated lysis of multiple myeloma cells in a hBCMA selective manner. The ability of a hBCMA x hCD16a dual engager to enhance NK cell mediated lysis of multiple myeloma cells in a BCMA selective manner was investigated. The compound that had SEQ ID No:85. Results Using engineered MM.1s target cells in which BCMA was either knocked out or overexpressed, a clear correlation between the BCMA expression level and NK cellactivation was observed (Figure 22). The data demonstrate that the dual engagercompound with SEQ ID No:85 a concentration of 100 nM elicits responses, withspecificity to BCMA. In the Figure, the results are shown for MM.1s wild type (WT), BCMA knock-out (KO), and BCMA overexpression (OE). Results are from one representative experiment (n=4). The following Examples relate to CD16a-binding polypeptides according to thepresent invention which comprises at least one motif that binds to CD16a, whereinsaid polypeptide comprises the following structure: [N-terminal portion]-[Helix-1]- [Separating portion]-[Helix2]-[C-terminal portion]; the CD16a binding motif being the portion [Helix-1]-[Separating portion]-[Helix2]; the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule.Preparative Example 1:Recombinant production of hPD-L1 × hBCMA × hCD16a trispecific engagersIn this Example, hPD-L1 × hBCMA × hCD16a trispecific engagers comprisinghCD16a binding polypeptides (compound IDs P1 and P2 - see Table 9 below) wereproduced by recombinant means The cDNA coding for each hPD-L1 × hBCMA × hCD16a trispecific engager harbouring a stop codon was synthesized and ligated into the Nde1 Xho1 restrictionsites of the pET29 vector. E coli BL21(DE3) was transformed with vector underKanamycin selection and constructs were expressed by induction of IPTG at an OD of 0.6 and harvested 16h later. Soluble cytosolic product was harvested and resuspended in 1xPBS. Heat denaturation for 7 min at 95 °C was applied and precipitated proteinwas pelleted by centrifugation at 20,000 × g. Further purification was achieved byRP-HPLC and identity / purity was confirmed by SDS-PAGE and LC / MS / MS analysis.The hBCMA and hCD16a binding arms were composed of the polypeptides of SEQID NO: 226 (aBCMA-1-E6):VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAEAKKL NDAQAPK as seen in Preparative Example 5 of published patent applicationPCT / EP2023 / 064624 and SEQ ID NO: 1 (aCD16-A10):VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLNDAQAPK) respectively.Sequences and SEQ ID NOs for the trispecific engagers produced are shown in Table 9 below. Table 9. Sequences of recombinantly produced PD-L1 x hBCMA × hCD16a trispecific engagers produced in Preparative Example 1.

[0287] Characterization Example 1: Mass spectrometry of the hPD-L1 × hBCMA × hCD16a trispecific engagers High-resolution quadrupole-time-of-flight mass spectrometry was used to characterise hPD-L1 × hBCMA × hCD16a trispecific engagers which were synthesised as described in Preparative Example 1. . The conditions employed were: Mobile Phases: A: 0.1% formic acid in MilliQ water. B: Acetonitrile Flow: 0.5 mL / min Column: C8, 3.6 µm, 2.1 x 100 mm (Phenomenex bioZen intact XB-C8) LC instrument: Agilent 1290 Infinity II system MS instrument: Agilent QTOF 6545 operating in positive Dual AJS ESI mode LC gradient: 0 min: 10%B; 10 min: 60%B; 10.1-12 min: 95%B; 12.1 min: 10%B Results The mass spectrometry results for the hPD-L1 × hBCMA × hCD16a trispecific engagers is shown in Table 10.Table 10. Mass spectrometry characterization of the hPD-L1 × hBCMA × hCD16atrispecific engagers

[0288] Biological Example 2 Determination of functional activity of hPD-L1 × hBCMA × hCD16a trispecific engagers In this Example, the ability of the hPD-L1 × hBCMA × hCD16a trispecific engagersproduced in Preparative Example 1 to disrupt PD-1 / PD-L1 inhibitory interactionand to stimulate hCD16a activation was assessed according to the protocols described below. Experimental protocols: NFAT Luciferase assays: hPD-1 / PD-L1 blockade luciferase reporter assay The propensity of the hPD-L1 × hBCMA × hCD16a trispecific engagers produced inPreparative Example 1 to block PD-1 / PD-L1 interaction was assessed in a LuciaLuciferase reporter assay and compared to the inhibitory effect of hPD-L1 antibody(N298A) (InvivoGen™). Jurkat-Lucia™ TCR-hPD-1 cells (effector cells;InvivoGen™) were either seeded with Raji-APC-hPD-L1 cells (target cells; InvivoGen™) at an effector to target (E:T) ratio of 2:1 in a 96-well flat-bottom plate, or in the absence of target cells. In total, 3x105cells in 200 μl per well were treatedwith 20 or 200 nM of engagers P1 and P2 for 24h. The supernatant was harvested,and Lucia luciferase activity, which indicates inhibitory responses, was assessed usingQUANTI Luc™ Gold (InvivoGen™). Responses were normalized to the inhibitoryresponse induced by 6.7nM hPD-L1 antibody (N298A) antibody (obtained from Invivogen™. Catalogue number: hpdl1-mab12 (https: / / www.invivogen.com / anti- hpdl1-higg1n298a). CD16a mediated ADCC luciferase reporter assay The propensity of the hPD-L1 × hBCMA × hCD16a trispecific engagers P1 and P2to induce hCD16a mediated ADCC was assessed in a Lucia Luciferase reporter assayby coculturing of Jurkat-Lucia™ NFAT-CD16 cells (effector cells; InvivoGen™)with either hBCMA+ MM.1S cells or with Raji-APC-hPD-L1 cells (InvivoGen™).Monoclonal antibodies to known targets on the target cells were used as positivecontrols of hCD16a activation. Responses from the co-culture of effector cells andMM.1S cells were normalized to the maximal response of 200nM elotuzumab(clinical grade anti-SLAMF7 monoclonal antibody) (Bristol-Myers Squibb) whereasresponses in the co-culture of effector cells and Raji-APC-hPD-L1 cells werenormalized to the activating response of 6.7nM hPD-L1 antibody (obtained fromInvivoGen™atalogue number: hpdl1-mab1. See https: / / www.invivogen.com / anti- hpdl1-higg1). The same experimental setup and detection method was used asdescribed for the PD-1 / PD-L1 blockade luciferase reporter assay.ResultsThe functional activity of the trispecific engagers P1 and P2 are shown in Figures25(a), (b) and (c).In Figure 25(a), it is clearly seen that the hPD-L1 × hBCMA × hCD16a trispecificengagers P1 and P2 demonstrated an inhibitory effect of the hPD-1 / PD-L1interaction in the presence of hPD-L1+Raji cells, whereas no detectable inhibition was seen in the absence of target cells. Thus, these data demonstrate functional hPD- L1 binding properties of the trispecific engagers P1 and P2.In Figure 25(b), it is clearly seen that the hPD-L1 × hBCMA × hCD16a trispecificengagers P1 and P2 induce CD16 activation, as measured by Lucia luciferase activityas a marker for response, in the presence of hBCMA+MM.1S cells, whereas no detectable activation was seen in the absence of target cells. Thus, these data demonstrate that both the hBCMA and the hCD16a binding domains of the trispecificengagers P1 and P2 are functionalIn Figure 25(c), it is clearly seen that the hPD-L1 × hBCMA × hCD16a trispecificengagers P1 and P2 induce CD16 activation, as measured by Lucia luciferase activityas a marker for response, in the presence of hPD-L1+ Raji cells, whereas no detectableactivation was seen in the absence of target cells. Thus, these data demonstrate thatboth the hPD-L1 and the hCD16a binding domains of the trispecific engagers P1 andP2 are functional.In conclusion, the trispecific engagers P1 and P2 can induce CD16 activation inresponse to both hPD-L1 and BCMA positive cells.Preparative Example 3Recombinant production of B7-H3 × hBCMA × hCD16a trispecific engagers andB7-H3 × hCD16a dispecific engagersIn this Example, the B7-H3 x hBCMA × hCD16a trispecific engagers comprising B7-H3x hBCMA & hCD16a binding polypeptides and B7-H3 × hCD16a dispecificengagers (compound IDs P3, P4, P17, P18, P19, P20 and P21) were produced byrecombinant means, and thereafter characterized with regard to their hCD16aactivation properties. The method described in Preparative Example 1 was used toproduce the trispecific and dispecific engagers. Identity / purity was confirmed by SDS-PAGE and LC / MS / MS analysis. The hBCMA and hCD16a binding arms were composed of the polypeptides ofSEQ ID NO: 226 (aBCMA-1-E6):VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAEAK KLNDAQAPK as seen in Preparative Example 5 of published PCT / EP2023 / 064624 andSEQ ID NO: 245 (aCD16-A10 (34a-A11)K18R:VDNKFNKEQQIAQYEIRRLPNLNHHQTFAFIKSLLDDPSQSANLLAEAKKLND AQAPK, and SEQ ID No:1 (aCD16-A10) VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEAKKLNDAQAPK. respectively. The B7H3 binding arms were composed of the polypeptides ofSEQ ID NO: 291 (aB7H3-AC12):AEAKYAKEKIAALSEIIWLPNLTHGQIMAFIAALNDDPSQSSELLSEAKKLNDS Q andSEQ ID NO: 292 (aB7H3-AC12-S179):AEAKFAKEKINALGEIIWLPNLTYDQIKAFIAKLNDDPSQSSELLSEAKKLSES Q, respectively Sequences and SEQ ID NOs for the trispecific and dispecific engagers produced are shown in the Table 11 below. Table 11. Sequences of recombinantly produced B7-H3 x hBCMA × hCD16a trispecific and B7-H3 × hCD16a dispecific engagers produced in Preparative Example 3.

[0289] Preparative Example 4Production of Alexa Fluor™ 647 labelled B7-H3 × B7-H3 × hCD16a trispecificengagers and Alexa Fluor™ 647 labelled B7-H3 × hCD16a dispecific engagersIn this Example, the B7-H3 x hBCMA × hCD16a trispecific engagers comprising B7-H3x hBCMA & hCD16a binding polypeptides (compound IDs P21 and P20; ) wereproduced by recombinant means according to the method described in PreparativeExample 1, followed by Alexa Fluor™647 carboxylic acid succinimidyl ester(invitrogen™, A20006) conjugation. Conjugation was performed at a molar ratio of1:2.5 in 1*PBS pH adjusted to 8.5 with carbonate buffer. The reaction was allowed torun for 1h at room temperature and then at 4 °C for an additional 16h. For isolation, the material was repurified using RP-HPLC producing labelled engagers.Identity / purity of the products, hereinafter referred to as P22 and P23 (see Table 12below), was confirmed by SDS-PAGE and LC / MS / MS analysis. Characterization Example 2: Mass spectrometry of B7-H3 × hBCMA × hCD16a trispecific and B7-H3 × hCD16adispecific engagers, for the Alexa Fluor™ 647 labelled B7-H3 × B7-H3 × hCD16atrispecific and B7-H3 × hCD16a dispecific engagersThe mass spectrometry analysis was performed according to the method described in Characterisation Example 1. Results The mass spectrometry results for the B7-H3 × hBCMA × hCD16a trispecific and andB7-H3 × hCD16a dispecific engagers, and for the Alexa Fluor™ 647 labelled B7-H3× B7-H3 × hCD16a trispecific and B7-H3 × hCD16a dispecific engagers is shown in Table 12. Table 12. Mass spectrometry characterization of the B7-H3 × hBCMA × hCD16atrispecific and dispecific engagers, and for the Alexa Fluor™ 647 labelled B7-H3 ×B7H3 × hCD16a trispecific and and B7-H3 × hCD16a dispecific engagers

[0290] Preparative Example 5a Synthetic engagers targeting CD16a and PD-L1: construction of monomeric hBCMA and hCD16a polypeptide ligandsThe polypeptide chains were constructed by means of linear solid-phase peptidesynthesis (SPPS), starting from the C-terminus amino acid. The method of synthesisemployed Fmoc solid-phase peptide synthesis, on a Symphony X peptide synthesizerfrom Gyros Protein Technologies. A pre-loaded Wang resin was used to obtain apeptide C-terminal acid product. Standard Fmoc-amino acids were employed with appropriate side chain protecting groups. Where applicable, standard coupling conditions were used in each case. In some instances, pseudoproline di-peptides were used. In some instances, some amino acids were double coupled. Reactions werecarried out in DMF at room temperature. The general synthetic workflow on thepolymeric support can be summarized into the following steps:1 Swelling of the resin with DMF2 Cleavage of the temporary protecting Fmoc group3 Washing of the resin with DMF4 Coupling of the second Fmoc-amino acid to a pre-loaded Wang resin5 Capping of any unreacted amino group6 Cleavage of the temporary protecting Fmoc group7 Coupling of the further Fmoc-amino acids or Fmoc-dipeptides8 Repeating steps 5 to 7 to form a peptide sequence9 Coupling of the last Fmoc-amino acid10 Last cleavage of the temporary protecting Fmoc group11 Cleavage of the polypeptide from the resin and simultaneous removal of the sidechain protecting groups The final molecules were purified by reverse phase HPLC using acetonitrile / water / TFA. The fractions were analysed by LCMS, and the appropriated fractions were pooled and lyophilized. General methods for purification and analysis Preparative HPLC was performed on a Gilson HPLC system using a Kinetex XB C18 (5 µm, 21x100 mm) column with 0.1% TFA in MilliQ H2O / CH3CN as mobile phase (acidic conditions) (flow 25 mL / min, gradient over 15 min). Product purity and molecular weight was confirmed on an Agilent 1260 Series liquid chromatography- mass spectrometry (LC-MS) system with a single quadrupole MS detector. Analytical HPLC separation was performed on a Kinetex XB C18 (2.6 µm, 3.0x100 mm) column with 0.1% TFA in MilliQ H2O / CH3CN as mobile phase (acidic conditions) (flow 0.85 mL / min). High-resolution quadrupole-time-of-flight mass spectrometry analyses were performed on an Agilent QTOF 6545 operating in positive Dual AJS ESI mode. Analytical HPLC separation was performed on a C8, 3.6 µm, 2.1 x 100 mm column (Phenomenex bioZen intact XB-C8), using A: 0.1% formic acid in MilliQ water. B: Acetonitrile and a flow of 0.5 mL / min. LC gradient: 0 min: 10%B; 10 min: 60%B; 10.1-12 min: 95%B; 12.1 min: 10%B. The aggregation level of the final engager variants was evaluated using size exclusion chromatography (SEC). The experiments were performed on an Agilent Series 1100 system using a cytiva Superdex 75 Increase 10 / 300 GL column with 1X PBS pH 7.4 (Phosphate Buffered Saline) as mobile phase with a flow of 0.3mL / min and UV- detection at 220nm using an Agilent Series 1100 diode array detector. As a size comparison, a calibrant of five different proteins were used (conalbumin 75 kDa, ovalbumin 44 kDa, carbonic anhydrase 29 kDa, ribonuclease A 13.7 kDa, and aprotinin 6.5 kDa). The monomeric CD16a-binding polypeptides were as follows: Table 13 The monomeric hBCMA-binding polypeptides were as follows: Table 13A The following special building blocks containing alkyne or azide functionalities wereused in the solid phase peptide synthesis:

[0291] Preparative Example 5b Assembly of sm_hPD-L1 × hCD16a dual engager dimeric constructs. In these Examples, the final targeting domains in dual engager constructs were produced by an alkyne azide click chemistry reaction.The sm_hPD-L1 and hCD16a constructs prepared are as follows:Table 14

[0292] Synthesis of P5 Synthesis of intermediate compound BB11 BB11 was synthesized as follows: 15.0 mg of starting material compound BB0 and9.0 mg of HATU were dissolved in approximately 1.0 mL of DMF. After stirring for 20 min, the mixture was treated with propargyl-PEG8 amine (10.0 mg), and DIPEA(12.0 µL) in DMF (0.1 mL). The resulting mixture was stirred at room temperaturefor 3 h. Reaction progress was monitored by LCMS until the final product was themajor product. The reaction mixture was purified by HPLC (prep-HPLC) to giveBB11 as a single peak, yield 9.0 mg (38% yield). LCMS (m / z) = 984 [M+H].The final compound was lyophilized from 0.1 % TFA in water to afford thetrifluoroacetate salt.1H-NMR (600 MHz, CD3CN) δ 7.94 (s, 1H), 7.79 (d, J = 7.9 Hz, 1H), 7.71 (d, J = 7.7 Hz, 1H), 7.56 (t, J = 7.8 Hz, 1H), 7.40 (dd, J = 7.5, 1.8 Hz, 1H), 7.30 (s, 1H), 7.26 – 7.16 (m, 3H), 6.91 (d, J = 8.2 Hz, 1H), 6.82 (d, J = 2.2 Hz, 1H), 6.77 (dd, J = 8.2, 2.2Hz, 1H), 6.76 (s, 1H), 5.29 – 5.20 (m, 2H), 5.14 (s, 2H), 4.28 (s, 5H), 4.26 – 4.18 (m,2H), 4.14 (d, J = 2.5 Hz, 2H), 3.99 (dd, J = 12.6, 3.7 Hz, 1H), 3.88 (t, J = 4.3 Hz, 1H),3.82 (dd, J = 12.5, 5.1 Hz, 1H), 3.65 (s, 1H), 3.59 (dd, J = 5.9, 3.3 Hz, 3H), 3.54 (dq, J= 4.4, 2.3 Hz, 27H), 3.45 – 3.37 (m, 2H), 3.23 (s, 1H), 2.25 (s, 3H), 2.14 (s, 3H).BB0 is the compound widely known as BMS1001: N-[[2-[(3-cyanophenyl)methoxy]- 4-[[3-(2,3-dihydro-1,4-benzodioxin-6-yl)-2-methylphenyl]methoxy]-5- methylphenyl]methyl]-D-serine, generally supplied in the form of itsmonohydrochloride salt. It has the CAS number 2113650-04-5 and is available frommany commercial suppliers, including MedChemExpress, Cayman Chemicals and Selleckchem. Synthesis of compound P5 P5 was synthesized as follows: 0.3 mg of BB11 and 2.0 mg of BB1 were dissolved inapproximately 1.0 mL of MeCN / PBS buffer pH 7.4 (2:8), and treated with BTTAA(0.3 µmol), CuSO4 (0.3 µmol), and sodium ascorbate (0.6 µmol). The resulting mixture was stirred at room temperature. Reaction progress was monitored by LCMSuntil the final compound was the major product. After 6 h, the reaction mixture waspurified by HPLC (prep-HPLC) to give P5 as a single peak, yield 2.1 mg. HPLC(95%). SEC (98%). Theoretical MW for high resolution MS: 8208.3 Da; calculatedaverage mass (neutral) from measured values: 8208.0 Da. Herein, where highresolution mass spectrometry analysis was carried out, a Theoretical MW is included in the text. Where the mass spectrometry data reported are from a low resolution mass spectrometry device, the theoretical MW is not indicated.Peptide was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt ofthe final compound. Synthesis of P6 Synthesis of intermediate compound BB12 BB12 was synthesized as follows: 7.0 mg of starting material compound compoundBB0 and 5.0 mg of HATU were dissolved in approximately 0.8 mL of DMF. Afterstirring for 10 min, the mixture was treated with DBCO amine (3.0 mg), and DIPEA (6.0 µL) as a solution in DMF (0,2 mL). The resulting mixture was stirred at roomtemperature for 3 h. Reaction progress was monitored by LCMS until the finalproduct was the major product. The reaction mixture was purified by HPLC (prep-HPLC) to give BB12 as a single peak, yield 4.0 mg (40% yield). LCMS (m / z) = 853[M+H]. The final compound was lyophilized from 0.1 % TFA in water to afford thetrifluoroacetate salt.1H-NMR (600 MHz, CD3CN) δ 7.88 – 7.85 (m, 1H), 7.74 (d, J = 7.8 Hz, 1H), 7.68 –7.60 (m, 2H), 7.51 (t, J = 7.8 Hz, 1H), 7.47 – 7.17 (m, 9H), 7.11 (d, J = 12.4 Hz, 1H),6.91 (d, J = 8.2 Hz, 1H), 6.87 (d, J = 6.9 Hz, 1H), 6.82 (t, J = 2.0 Hz, 1H), 6.77 (dt, J =8.3, 1.8 Hz, 1H), 6.71 (d, J = 8.9 Hz, 1H), 5.23 – 5.14 (m, 2H), 5.11 (s, 3H), 5.05 (dd,J = 14.1, 2.2 Hz, 1H), 4.28 (s, 5H), 4.15 – 4.06 (m, 2H), 3.78 (dd, J = 12.9, 3.6 Hz,1H), 3.73 – 3.60 (m, 3H), 3.54 (ddd, J = 13.2, 8.3, 5.4 Hz, 1H), 3.16 (tt, J = 12.5, 6.6Hz, 1H), 3.05 (ddd, J = 20.4, 13.5, 6.7 Hz, 1H), 2.40 (tt, J = 15.7, 6.2 Hz, 1H), 2.23 (s,3H), 2.14 – 2.09 (m, 3H), 1.91 – 1.79 (m, 1H).Synthesis of compound P6 P6 was synthesized as follows: 0.38 mg of BB12 and 2.0 mg of starting materialcompound BB1 were dissolved in approximately 1.3 mL of DMF / PBS buffer pH 7.4(2:8), and the resulting mixture was stirred at room temperature for 20 h. Reaction progress was monitored by LCMS until good conversion towards the final product.The final compound was purified by HPLC (prep-HPLC) to give P6 as a single peak,yield 1.3 mg. HPLC (98%). Theoretical MW for high resolution MS: 8077.1 Da;calculated average mass (neutral) from measured values: 8077.0 Da.Peptide was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt ofthe final compound. 0.6 mg of the isomeric final product were also obtained. HPLC (96%). TheoreticalMW for high resolution MS: 8077.1 Da; calculated average mass (neutral) frommeasured values: 8076.8 Da. The isomeric product is believed to be: Synthesis of P7 Synthesis of intermediate BB13 BB13 was synthesized as follows: 15.0 mg of starting material compound BB0 and9.0 mg of HATU were dissolved in approximately 1.0 mL of DMF. After stirring for 20 min, the mixture was treated with propargyl-PEG24 amine (26.0 mg), and DIPEA (12.0 µL) in DMF (0.1 mL). The resulting mixture was stirred at room temperature for 7 h. Reaction progress was monitored by LCMS until the final product was the major product. The reaction mixture was purified by HPLC (prep-HPLC) to giveBB13 as a single peak, yield 9.3 mg (23% yield). LCMS (m / z) = 845 [M+2H] and853 [M+H+NH4]. The final compound was lyophilized from 0.1 % TFA in water to afford thetrifluoroacetate salt.1H-NMR (600 MHz, CD3CN) δ 7.95 (s, 1H), 7.79 (d, J = 7.9 Hz, 1H), 7.71 (d, J = 7.9Hz, 1H), 7.56 (t, J = 7.8 Hz, 1H), 7.40 (m, 1H), 7.28 (m, 1H), 7.25 – 7.18 (m, 3H),6.92 (d, J = 8.2 Hz, 1H) 682 (d J = 21 Hz 1H) 677 (m 1H), 6.76 (m, 1H), 5.28 –5.22 (m, 2H), 5.14 (s, 2H), 4.28 (s, 4H), 4.25 – 4.19 (m, 2H), 4.14 (d, J = 2.5 Hz, 2H),3.97 (dd, J = 12.6, 3.7 Hz, 1H), 3.88 (m, 1H), 3.82 (dd, J = 12.5, 5.1 Hz, 1H), 3.59 -3.49 (m, 90H), 3.48 – 3.37 (m, 4H), 3.33 (m, 2H), 3.27 (m, 2H), 2.71 (m, 1H), 2.25 (s,3H), 2.14 (s, 3H). Synthesis of P7 P7 was synthesized as follows: 0.7 mg of BB13 and 2.0 mg of starting materialcompound BB1 were dissolved in approximately 1.0 mL of MeCN / PBS buffer pH 7.4(1:9), and treated with BTTAA (0.4 µmol), CuSO4 (0.4 µmol), and sodium ascorbate (0.8 µmol). The resulting mixture was stirred at room temperature. Reaction progress was monitored by LCMS until the final compound was the major product. After 1.5 h,the reaction mixture was purified by HPLC (prep-HPLC) to give P7 as a single peak,yield 1.8 mg. HPLC (98%). SEC (99%). Theoretical MW for high resolution MS:8913.1 Da; calculated average mass (neutral) from measured values: 8912.7 Da.Peptide was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt ofthe final compound.Synthesis of C1 C1 was synthesized as follows: 0.2 mg of Propargyl-PEG8-amine and 1.8 mg BB1were dissolved in approximately 1.0 mL of MeCN / PBS buffer pH 7.4 (1:9), and treated with BTTAA (0.2 µmol), CuSO4 (0.2 µmol), and sodium ascorbate (0.5 µmol). The resulting mixture was stirred at room temperature. Reaction progress was monitored by LCMS until the final compound was the major product. After 1 h, thereaction mixture was directly purified by HPLC (prep-HPLC) to give C1 as a singlepeak, yield 1.9 mg. HPLC (92%). Calculated average mass (neutral) from measuredvalues: 7631 Da.Peptide was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt ofthe final compound. Synthesis of P8 Synthesis of intermediate BB14 BB14 was synthesized as follows: 10.0 mg of compound BB0 and 6.0 mg of HATUwere dissolved in approximately 1.0 mL of DMF. After stirring for 20 min, the mixture was treated with propargyl amine (1.0 mg), and DIPEA (9.0 µL) in DMF (0.1 mL). The resulting mixture was stirred at room temperature for 4 h. Reaction progress was monitored by LCMS until the final product was the major product. The reactionmixture was purified by HPLC (prep-HPLC) to give BB14 as a single peak, yield 3.0mg (28% yield). LCMS (m / z) = 632 [M+H]. The final compound was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt.1H-NMR (600 MHz, CD3CN) δ 7.92 (s, 1H), 7.79 (d, J = 7.9 Hz, 1H), 7.73 – 7.68 (m,1H), 7.56 (t, J = 7.8 Hz, 1H), 7.39 (dd, J = 7.2, 1.8 Hz, 1H), 7.38 (s, 1H), 7.26 – 7.18(m, 2H), 7.16 (s, 1H), 6.91 (d, J = 8.2 Hz, 1H), 6.82 (d, J = 2.1 Hz, 1H), 6.77 (dd, J =8.2, 2.2 Hz, 1H), 6.74 (s, 1H), 5.28 – 5.21 (m, 2H), 5.12 (s, 2H), 4.28 (s, 4H), 4.20 (q,J = 13.1 Hz, 2H), 3.98 (dd, J = 12.6, 3.4 Hz, 1H), 3.89 (td, J = 5.0, 2.5 Hz, 2H), 3.83 (t, J = 4.3 Hz, 1H), 3.79 (dd, J = 12.4, 5.1 Hz, 1H), 2.47 (m, 1H), 2.24 (s, 3H), 2.13 (s, 3H). Synthesis of P8 P8 was synthesized as follows: 0.3 mg of BB14 and 2.0 mg of BB1 were dissolved inapproximately 1.1 mL of MeCN / PBS buffer pH 7.4 (2:8), and treated with BTTAA(0.4 µmol), CuSO4 (0.4 µmol), and sodium ascorbate (0.8 µmol). The resultingmixture was stirred at room temperature. Reaction progress was monitored by LCMS until the final compound was the major product. After 17 h, the reaction mixture waspurified by HPLC (prep-HPLC) to give P8 as a single peak, yield 1.4 mg. HPLC(96%). SEC (98%). Theoretical MW for high resolution MS: 7855.9 Da; calculatedaverage mass (neutral) from measured values: 7855.8 Da, and 7366.3 Da(fragmentation).Peptide was lyophilized from 0.1 % TFA in water to afford the trifluoroacetate salt ofthe final compound. Synthesis of P9 Synthesis of intermediate BB15a A mi...

Claims

Claims 1. A CD16a-binding polypeptide, which comprises at least one motif that binds to CD16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]- [Helix 2]; the CD16a-binding polypeptide further comprising at least one additional functional portion, wherein the at least one functional portion comprises an additional binding moiety which is a binding partner recognising a protein in the B7 family and which is a polypeptide, peptide or small molecule.

2. The CD16a-binding polypeptide as claimed in claim 1, wherein: Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, [SEQ ID NO: 120] wherein, b) X9 is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; X11 is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is Q or R; X18 is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24 is H; X25 is A or H; X27 is A, I, K, Q, R, S, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M, R or S; orb) X9 is V; X10 is Q; X11 is M; X13 is Q; X14 is F; X17 is R; X18 is K; X24 is H; X25 is H; X27 is S; X28 is F; X31 is I; X32 is K; X33 is S and X35 is M, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least at least 1 and no more than 5 (for example 1 and no more than 3) of the residues not labelled as Xn are replaced by an alternative residue; or c) X9 is Q; X10 is F; X11 is Y; X13 is R; X14 is D; X17 is D; X18 is L; X24 is E; X25 is D; X27 is K; X28 is W; X31 is Y; X32 is M; X33 is S and X35 is I, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xn are replaced by an alternative residue; or d) X9 is F; X10 is W; X11 is I; X13 is E; X14 is S; X17 is E; X18 is S; X24 is I; X25 is Y; X27 is K; X28 is W; X31 is K; X32 is Y; X33 is S and X35 is A, and optionally wherein within Helix 1 and Helix 2, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xn are replaced by an alternative residue.

3. The CD16a-binding polypeptide as claimed in claim 1 or claim 2, wherein: Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 [SEQ ID NO 127] and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35, [SEQ ID NO: 120] wherein, X9 is A, D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; X11 is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is A, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is Q or R; X18 is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24 is H; X25 is A or H; X27 is A, I, K, Q, R, S, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M, R or S.

4. The CD16a-binding polypeptide as claimed in any preceding claim, wherein: Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 [SEQ ID NO 127] and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35 [SEQ ID NO: 120], wherein, X9 is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; X11 is A, D, E, F, H, I, K, L, M, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is F, H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; X18 is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24 is H; X25 is H or A; X27 is A, I, K, Q, R, T, S or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, M, R or S.

5. The CD16a-binding polypeptide as claimed in any preceding claim, wherein: Helix 1 comprises the sequence X9X10X11AX13X14EIX17X18 [SEQ ID NO: 127] and Helix 2 comprises the sequence X24X25QX27X28AFX31X32 X33LX35 [SEQ ID NO: 120], wherein, X9 is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; X11 is A, D, E, F, H, I, K, L, N Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is H, I, K, L, N, Q, R, S, T, V, W or Y; X17 is R or Q; X18 is A, D, E, F, H, I, K, N, Q, R, S, T or V; X24 is H; X25 is H or A; X27 is A, I, K, Q, R, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, L, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

6. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is D, F, H, I, K, L, Q, R, T, V, or Y; X10 is Q; X11 is A, D, E, F, H, I, K, N, Q, R, S, T, V, W or Y; X13 is A, Q or V; X14 is H, I, K, L, N, Q, R, S, V, W, or Y; X17 is R; X18 is A, D, E, F, H, K, N, Q, R, S or T; X24 is H; X25 is H; X27 is A, I, K, Q, R, T or V; X28 is F; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is H, I, L, R or S.

7. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is D, F, H, I, K, L, Q, T, V, or Y; X10 is Q; X11 is A, D, E, F, H, I, K, L, N, Q, R, S, T, V, W or Y; X13 is A or Q; X14 is H, I, K, L, Q, R, S, T, V, W or Y;X17 is R; X18 is A, D, E, F, H, K, N, Q, R, S, T or V; X24 is H; X25 is H; X27 is A, I, K, Q, R, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L or R.

8. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is D, F, H, I, K, L, Q, R, T, V or Y; X10 is Q; X11 is A, D, E, F, H, I, K, N, Q, R, S, T, V, W or Y; X13 is A or Q; X14 is H, I, K, L, Q, R, S, V, W or Y; X17 is R; X18 is A, F, H, K, N, Q, R, S or T; X24 is H; X25 is H; X27 is A, I, K, Q, R, T or V; X28 is F or Y; X31 is I or L; X32 is E, H, K, N, Q or R; X33 is K or S; and X35 is A, H, I, L, R or S.

9. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is F, L, Q, T or Y; X10 is Q; X11 is A, F, H, I, L, N, Q, S or Y; X13 is A or Q; X14 is I, K, Q, R or V; X17 is R; X18 is A, E, H, K, Q, R, T or V; X24 is H; X25 is H; X27 is A, I, K, Q, R or V; X28 is F; X31 is I; X32 is A, H, K, N, Q or R; X33 is K or S; and X35 is H, I or L.

10. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is I, L, Q, T or V; X10 is Q; X11 is A, E, F, H, I, S, V or Y; X13 is Q; X14 is K, L, R, V, W or Y; X17 is R; X18 is A, H, K, Q, R, S or T; X24 is H; X25 is H; X27 is I, K, Q, R, T or V; X28 is F; X31 is I or L; X32 is K, N or R; X33 is K or S; and X35 is I or L.

11. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is I, L, Q or V; X10 is Q; X11 is A, E, H, I, S, W or Y; X13 is Q; X14 is K, L, R, V, W or Y;X17 is R; X18 is A, H, K, Q, R, S or T; X24 is H; X25 is H; X27 is K, Q, R, T or V; X28 is F; X31 is I; X32 is K, N or R; X33 is K or S; and X35 is I or L; for example wherein:X9 is I, L, Q or V; X10 is Q; X11 is A, E, H, I, S or Y; X13 is Q; X14 is K, L, R, V, W or Y;X17 is R; X18 is H, K, Q, R, S or T; X24 is H; X25 is H; X27 is K, Q, R, T or V; X28 is F; X31 is I; X32 is N or K; X33 is K or S; and X35 is I or L.

12. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is L or V; X10 is Q; X11 is A, I, S or Y; X13 is Q; X14 is K, R or V; X17 is R; X18 is K, Q, R, S or T; X24 is H; X25 is H; X27 is K, R or V; X28 is F; X31 is I; X32 is N or K; X33 is K or S; and X35 is I or L.

13. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is D, H, I, K, L, Q, T or V; X10 is Q; X11 is A, D, E, F, H, I, K, N, R, S, V, W or Y; X13 is Q; X14 is K, L, Q, R, S, V, W or Y; X17 is R; X18 is A, H, K, N, Q, R, S or T; X24 is H; X25 is H; X27 is A, I, K, Q, R, T or V; X28 is F or Y; X31 is I or L; X32 is A, E, H, K, N, Q or R;X33 is K or S; and X35 is A, I, L, or R; or X9 is K, Q or Y; X10 is Q; X11 is I or Q; X13 is Q;X14 is W or Y; X17 is R; X18 is H, K or R; X24 is H; X25 is H; X27 is A, K or T; X28 is F; X31 is I; X32 is A, K or Q; X33 is K or S; and X35 is I or L; or X9 is L, V or Y; X10 is Q; X11 is I, N or Q; X13 is Q;X14 is K, R or Q; X17 is R; X18 is E, A or V; X24 is H; X25 is H; X27 is K or Q; X28 is F; X31 is I; X32 is H, K or Q; X33 is K or S; and X35 is I or L.

14. The CD16a-binding polypeptide as claimed in claim 5, wherein: X9 is L, Q, T or V; X10 is Q; X11 is I, V or Y; X13 is Q; X14 is K, R or Y; X17 is R; X18 is K, R, S or T; X24 is H; X25 is H; X27 is I, T or V; X28 is F; X31 is I or L; X32 is K or N; X33 is K or S; and X35 is I or L; for example wherein X9 is L, T or V; X10 is Q; X11 is I, V, or Y; X13 is Q;X14 is K or R; X17 is R; X18 is R, S or T; X24 is H; X25 is H; X27 is I or V; X28 is F; X31 is I or L; X32 is K or N; X33 is K; and X35 is I or L.

15. The CD16a-binding polypeptide as claimed in claims 2-14, wherein the CD16a binding efficacy is at least 10% of SEQ ID NO: 1; and / or wherein the CD16a-binding polypeptide competes with SEQ ID NO: 1.

16. The CD16a-binding polypeptide as claimed in claim 2 to 14, wherein: Helix 1 comprises the sequence X6X7X8X9X10X11AX13X14EIX17X18X19 and / or Helix 2 comprises the sequence X23X24X25QX27X28AFX31X32X33LX35X36X37 [SEQ ID NO: 128], wherein, X6 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X7 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; X8 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably E) or is absent; X19 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L) or is absent; X23 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X36 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; and X37 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; and preferably wherein X6 is N; X7 is K; and X8 is E; and / or wherein X36 is D; and X37 is D; for example wherein X6 is N; X7 is K; X8 is E; X19 is L; X23 is N; X36 is D; and X37 is D.

17. The CD16a-binding polypeptide as claimed in any of claims 2 to 4, wherein: Helix 1 comprises the sequence NKEVQMAQFEIRKL [SEQ ID NO: 129] and Helix 2 comprises the sequence NHHQSFAFIKSLMDD [SEQ ID NO: 130]; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5) (for example, at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by analternative residue (for example replaced by an alternative residue that is a conservative replacement).

18. The CD16a-binding polypeptide as claimed in claim 17, wherein the CD16a binding efficacy is at least 10% of SEQ ID NO: 1; and / or wherein the CD16a- binding polypeptide competes with SEQ ID NO:

1.

19. The CD16a-binding polypeptide as claimed in claim 2, wherein: Helix 1 comprises the sequence NKEQFYARDEIDLL [SEQ ID NO: 131] and Helix 2 comprises the sequence NEDQKWAFYMSLIDD [SEQ ID NO: 132]; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5) (for example, at least 1 and no more than 3 (for example 1, 2, or 3)) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

20. The CD16a-binding polypeptide as claimed in claim 19, wherein the CD16a binding efficacy is at least 10% of SEQ ID NO: 74; and / or wherein the CD16a-binding polypeptide competes with SEQ ID NO:

74.

21. The CD16a-binding polypeptide as claimed in claim 2, wherein: Helix 1 comprises the sequence NKEFWIAESEIESL [SEQ ID NO: 133] and Helix 2 comprises the sequence NIYQKWAFKYSLADD [SEQ ID NO: 134]; and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5) (for example, at least 1 and no more than 3 (for example 1, 2, or 3) residues in the sequence of Helix 1 and / or Helix 2 are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

22. The CD16a-binding polypeptide as claimed in claim 21, wherein the CD16a binding efficacy is at least 10% of SEQ ID NO: 75; and / or wherein the CD16a-binding polypeptide competes with SEQ ID NO:

75.

23. The CD16a-binding polypeptide as claimed in any preceding claim wherein the separating portion is a sequence of 1 to 5 (preferably 2 to 5, for example 2,3, 4 or 5; or for example 3 to 5, for example 3, 4 or 5, and more preferably 3) naturally occurring amino acids.

24. The CD16a-binding polypeptide as claimed in any preceding claim wherein the separating portion has the sequence X20X21X22, wherein X20 is any naturally occurring amino acid (preferably S, T, M, P, F, Y or W; more preferably P or T); X21 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N); X22 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L); and wherein optionally one or two (for example optionally 1) of X20 , X21 , X22 are absent; and preferably wherein X20 is P or T; X21 is N; and X22 is L (for example, the separating portion has the sequence PNL or TNL).

25. The CD16a-binding polypeptide as claimed in any preceding claim, wherein the N-terminal portion is absent or is a sequence of 1 to 15 (preferably 1 to 10 or 1 to 8, more preferably 1 to 5, for example 1, 2, 34 or 5) naturally occurring amino acids.

26. The CD16a-binding polypeptide as claimed in any preceding claim wherein the N-terminal portion has the sequence X1X2X3X4X5, wherein X1 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably V or G; and most preferably V) or is absent; X2 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; X3 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X4 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; andX5 is any naturally occurring amino acid (preferably F, Y or W; more preferably F) or is absent; and preferably wherein X1 is V, G or absent (preferably V or absent), X2 is D or absent, X3 is N or absent, X4 is K or absent, and X5 is F or absent.

27. The CD16a-binding polypeptide as claimed in any preceding claim, wherein the N-terminal portion is absent, or the N-terminal portion has the sequence X1X2X3X4X5 wherein X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is D, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is absent, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is F.

28. The CD16a-binding polypeptide as claimed in any preceding claim, wherein the C-terminal portion is absent or is a sequence of 1 to 50 (for example 1 to 35, 1 to 30, 15 to 25 or 18 to 22) naturally occurring amino acids.

29. CD16a-binding polypeptide as claimed in claim 28 wherein the C-terminal portion has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58 [SEQ ID NO: 135], wherein, X38 is a sequence of 1 to 14 (preferably 1 to 9 or 1 to 7, more preferably 1 to 4, for example 1, 2, 3 or 4) naturally occurring amino acids (and preferably X38 is any naturally occurring amino acid (most preferably X38 is P)); X39 is any naturally occurring amino acid (preferably S, T, M, P, F, Y or W; more preferably S); X56 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably A) or is absent; X57 is any naturally occurring amino acid (preferably P) or is absent; andX58 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; (for example X38 is P; X39 is S; X56 is A or absent; X57 is P or absent; X58 is K or absent) and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 34 or 5) (preferably at least 1 and no more than 3 (for example 1, 2, or 3)) of the residues in the sequence QSANLLAEAKKLNDAQ [SEQ ID NO: 136] are replaced by an alternative residue; and preferably optionally wherein, at least 1 and no more than 5 (for example 1, 2, 34 or 5) (preferably at least 1 and no more than 3 (for example 1, 2, or 3)) of the residues in the sequence QSANLLAEAKKLNDAQ [SEQ ID NO: 136] are replaced by an alternative residue that is a conservative replacement.

30. CD16a-binding polypeptide as claimed in claim 29 wherein the C-terminal portion has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58 [SEQ ID NO: 135], wherein X56 is A, X57 is P, and X58 is K; X56 is A; or X57 is P, and X58 is absent; X56 is A, X57 is absent; and X58 is absent; or X56 is absent, X57 is absent, and X58 is absent; and optionally wherein, at least 1 and no more than 3 (for example 1, 2, or 3) of the residues in the sequence QSANLLAEAKKLNDAQ [SEQ ID NO: 136] are replaced by an alternative residue; and preferably optionally wherein, at least 1 and no more than 3 (for example 1, 2, or 3) of the residues in the sequence QSANLLAEAKKLNDAQ [SEQ ID NO: 136] are replaced by an alternative residue that is a conservative replacement; and preferably wherein X38 is P and X39 is S.

31. The CD16a-binding polypeptide as claimed in any preceding claim, wherein: (i) the separating portion has the sequence X20X21X22; and / orthe N-terminal portion has the sequence X1X2X3X4X5 ; and / or the C-terminal portion has the sequence PSQSANLLAEAKKLNDAQX56X57X58 [SEQ ID NO: 137]; wherein, in said separating portion, X20 is P or T; X21 is N; X22 is L; wherein in said N-terminal portion, X1 is V or G (preferably V), or absent; X2 is D or absent; X3 is N or absent; X4 is K or absent; X5 is F or absent; and wherein in said C-terminal portion, X56 is A or absent; X57 is P or absent; X58 is K or absent; or (ii) the separating portion, N-terminal portion, and C-terminal portion are as defined in (i), wherein optionally (a) within each portion 1, 2 or 3 residues are replaced by an alternative residue; or (b) within those portions taken together at least 1 and no more than 10 (for example, not more than 5, for example 1, 2, 3, 4, or 5) residues are replaced by an alternative residue.

32. The CD16a-binding polypeptide as claimed in any preceding claim, wherein said separating portion has the sequence PNL or TNL; and / or wherein said N- terminal portion has the sequence VDNKF [SEQ ID NO: 138].

33. A CD16a-binding polypeptide as claimed in any preceding claim, wherein the CD16a-binding motif sequence is selected from SEQ ID Nos: 150 to 221 and 1014 to 1026 and 1044; preferably from SEQ ID NOs. 166, 168, 178, 182, 202 or 1014; or preferably from SEQ ID Nos: 164, 166, 168, 200 or 1014 (for example 164, 166, 168 or 1014); for example, from SEQ ID Nos: 150, 166 or 200;and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably a residue that is a conservative replacement.

34. The CD16a-binding polypeptide as claimed in claim 1 or 2, which comprises a sequence selected from SEQ ID Nos: 1-75, and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement; or the CD16a-binding polypeptide as claimed in any one of claims 1 to 3, which comprises a sequence selected from SEQ ID Nos: 1-73, and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement; or the CD16a-binding polypeptide as claimed in any one of claims 1 to 4, which comprises a sequence selected from SEQ ID Nos: 1 or 11 to 67, and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement; or the CD16a-binding polypeptide as claimed in any one of claims 1 to 5, which comprises a sequence selected from SEQ ID Nos: 11 to 67, and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement.

35. The CD16a-binding polypeptide as claimed in claims 1 to 4, wherein the sequence of the CD16a-binding polypeptide is selected from: VDNKFNKEVQMAQFEIRKLPNLNHHQSFAFIKSLMDDPSQSANLLAEA KKLNDAQAPK [SEQ ID NO: 1]VDNKFNKELQNAQREIRALPNLNHHQQFAFIHKLIDDPSQSANLLAEA KKLNDAQAPK [SEQ ID NO:35]; or VDNKFNKEQQIAQYEIRKLPNLNHHQTFAFIKSLLDDPSQSANLLAEA KKLNDAQAPK [SEQ ID NO:51] 36. The CD16a-binding polypeptide as claimed in claim 1 or claim 2, wherein the sequence of the CD16a-binding polypeptide is selected from: VDNKFNKEQFYARDEIDLLPNLNEDQKWAFYMSLIDDPSQSANLLAE AKKLNDAQAPK [SEQ ID NO: 74]; and; VDNKFNKEFWIAESEIESLPNLNIYQKWAFKYSLADDPSQSANLLAEA KKLNDAQAPK [SEQ ID NO: 75].

37. The CD16a-binding polypeptide as claimed in claim 1 or claim 2, wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID Nos: 12, 17, 19, 29, 33, 49, 51, and 53; for example SEQ ID Nos: 17, 19, 29, 33, and 53; or wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID NOs.19, 33, 17, 29, 53, 16, 25, 15, 51, 36, 49, 55, 43, 24, 56, 12, 28, 21, 59, 52, 32, 18, 27, 35 or 11; or 34, 45 or 51; or 26, 35 or 47; or wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID Nos: 1001 to 1013 and 1043.

38. The CD16a-binding polypeptide as claimed in claim 1 or claim 2, wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID Nos:15, 17, 19, 35, 51; for example 15, 19 or 17; or wherein the sequence of the CD16a polypeptide is SEQ ID NO: 1001.

39. The CD16a-binding polypeptide according to any preceding claim, wherein the CD16a-binding polypeptide does not comprise methionine.

40. The CD16a-binding polypeptide with a sequence according to any of claims 2 to 39, wherein, at a position at which a methionine residue is recited, the polypeptide has the sequence with the methionine residue independently substituted for a different naturally occurring amino acid or an unnatural amino acid (for example a different naturally occurring amino acid ornorleucine); and preferably each methionine residue is independently substituted for an amino acid selected from isoleucine (I), leucine (L), glutamine (Q) norleucine, homoleucine and tert-butylalanine; and more preferably each methionine residue is independently substituted for a norleucine or isoleucine.

41. The CD16a-binding polypeptide according to any preceding claim, wherein one or more residues (for example 1 to 5 residues, for example 1, 2 ,3, 4 or 5) of the CD16a-binding polypeptide is / are substituted for an unnatural amino acid, for example norleucine; and / or wherein one or more methionine residues, when present (for example 1 or 2 methionine residue(s) when present), is / are substituted for an unnatural amino acid, for example norleucine; and / or wherein one or more leucine residues, when present (for example 1 to 5 leucine residues, when present), is / are substituted for norleucine; and / or wherein one or more methionine residues, when present (for example 1 or 2 methionine residue(s) when present), is / are oxidised (for example is / are Met(O)).

42. The CD16a-binding polypeptide according to any preceding claim, wherein the additional binding moiety is a polypeptide, peptide or small molecule recognising PD-L1 or B7-H3.

43. The CD16a-binding polypeptide according to claim 42, wherein the additional binding moiety which is a binding partner recognising PD-L1 is a polypeptide, for example a polypeptide comprising at least one motif that binds to PD-L1, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1a]-[Separating portion]-[Helix 2a]-[C-terminal portion], the PD-L1-binding motif being the portion [Helix 1a]-[Separating portion]- [Helix 2a].

44. The CD16a-binding polypeptide according to claim 43, wherein the additional binding moiety which is a binding partner recognising PD-L1 comprises a PD- L1 binding module having the sequence ERNX4AAX7EIL X11LPNLX16X17X18QX20 WAFIWX26LX28D wherein, independently from each other, X4 is selected from A, D, E, F, H, I, K, L, N, Q, R, S, T, V and Y; X7 is selected from A, E, F, H, N, Q, S, T, V, W and Y; X11 is selected from A, D, E, F, H, K, L, N, Q, R, S, T, V, W and Y; X16 is selected from N and T; X17 is selected from A, H, K, N, Q, R and S; X18 is selected from A, D, E, G, H, K, L, N, Q, R, S, T, V and Y; X20 is selected from H, I, K, L, N, Q, R, T, V and Y; X26 is selected from K and S; and X28 is selected from A, D and E; preferably wherein the additional binding moiety which is a binding partner recognising PD-L1 is a polypeptide having the sequence AEAKYAKERNAAAYEILYLPNLTNAQKWAFIWKLDDDPSQSSELLSE AKKLNDSQAPKVD 45. The CD16a-binding polypeptide according to claim 42, wherein the additional binding moiety which is a binding partner recognising PD-L1 is a peptide, for example a peptide selected from the group consisting of BMS-986189, BMSpep-57, BMS-57, BMS-71, BMS-99 and BMS-91.

46. The CD16a-binding polypeptide according to claim 42, wherein the additional binding moiety which is a binding partner recognising PD-L1 is a small molecule, for example a small molecule selected from the group consisting of BMS-8, BMS-200, BMS-202, BMS-1165, BMS-1166, BMS-1016, BMS- 2007, BMS-40210 and BMS-1001.

47. The CD16a-binding polypeptide according to claim 46, wherein the additional binding moiety which is a binding partner recognising PD-L1 is BMS-1001.

48. The CD16a-binding polypeptide according to claim 42, wherein the additional binding moiety is a polypeptide recognising B7-H3 for example a polypeptidecomprising at least one motif that binds to B7-H3, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1c]-[Separating portion]-[Helix 2c]-[C-terminal portion], the PD-L1-binding motif being the portion [Helix 1c]-[Separating portion]- [Helix 2c], for example a polypeptide comprising the sequence: AEAKYAKEKX1X2AX3X4EIX5WLPNLTHGQIMAFIAALND where X1 is selected from I or V; X2 is selected from F, I, A, H; X3is selected from L, V; X4is selected from G or S; X5 is selected from Y or I; for example, a polypeptide comprising the sequence AEAKYAKEKIAALSEIIWLPNLTHGQIMAFIAALND [SEQ ID NO:290] or for example a polypeptide comprising the sequence: AEAKF AKEKI NALGE IIWLP NLTYD QIKAF IAKLN DDPSQ SSELL SEAKK LSESQ [SEQ ID NO.292] or the sequence: AEAKF AKEKI KALSE IIWLP NLTYG QIKAF IAKLN DDPSQ SSELL SEAKK LSESQ [SEQ ID NO.293].

49. The CD16a-binding polypeptide as claimed in any preceding claim, wherein the CD16a-binding polypeptide and the additional binding moiety are each separated by a linker.

50. The CD16a-binding polypeptide as claimed in claim 49, wherein the linker is a sequence of 1 to 50 (for example 1 to 25) naturally occurring amino acids; preferably 1 to 25 (for example 1 to 20) naturally occurring amino acids selected from the group consisting of G, S and T (preferably G and S).

51. The CD16a-binding polypeptide as claimed in claims 49 or 50, wherein the linker is G or comprises the sequence GGGSG [SEQ ID NO: 139], GGGGS [SEQ ID NO: 140], GGSGG [SEQ ID NO: 141], GSGGG [SEQ ID NO: 142] and / or SGGGG [SEQ ID NO: 143]; for example wherein the linker is G orcomprises or has the sequence GGGSG, GGGSGGGGSG [SEQ ID NO: 144], GGGSGGGGSGGGGSG [SEQ ID NO: 145], GGGSGGGGSGGGGSGGGGSG [SEQ ID NO: 146], GGSGG, GGSGGGGSGG [SEQ ID NO: 147], GGSGGGGSGGGGSGG [SEQ ID NO: 148] or GGSGGGGSGGGGSGGGGSGG [SEQ ID NO: 149].

52. The CD16a-binding polypeptide as claimed in claim 49, wherein the or each linker comprises one or more groups selected from the group consisting of triazole (for example a 1,4- or 1,5-substituted triazole), a bicyclic ring comprising a triazole ring (for example a triazole fused cyclooctane, mono- or di-fluorocyclooctane), a tricyclic ring comprising a triazole ring (for example a triazole fused bicyclononane), a tetracyclic ring comprising a triazole ring (for example a triazole fused dibenzocyclooctane or dibenzoazacyclooctane ring), a bicyclic ring comprising a pyridazine ring (for example a pyridazine fused cyclooctane), a tricyclic ring comprising a pyridazine ring (for example pyridazine fused bicyclononane), 1H-pyrrole-2,5-dione,whereingroup, wherein z is 1 to 4.

53. The CD16a-binding polypeptide as claimed in claim 52, wherein the or each linker comprises one or more groups selected from the group consisting of,54. The CD16a-binding polypeptide as claimed in any of claims 52 and 53, wherein at least one linker (for example the, one or each linker) comprises one or more groups selected from the group consisting of,w ee p s o ,,1, 2 or 3; and55. The CD16a-binding polypeptide as claimed in any of claims 52 to 54, wherein at least one linker (for example the, one or each linker) comprises one or more (for example one or two) groups selected from the group consisting of.

56. The CD16a-binding polypeptide as claimed in any of claims 52 to 55, wherein at least one linker (for example the, one or each linker) comprises one or more (for example one or two) groups selected from the group consisting ofwherein n is 1 to 30.

57. The CD16a-binding polypeptide as claimed in any of claims 52 to 56, wherein at least one linker (for example the, one, or each linker) comprises one or two triazoles (for example one or two ) and optionally furthercomprises one or more (for example one, two, three or four)wherein n is 1 to 24 (for example 1 to 16, 1 to 12, 1 to 8, or 2 to 8, and especially 2, 3 or 4) and / or one or more (for example one).

58. The CD16a-binding polypeptide as claimed in any of claims 52 to 57, wherein each linker further comprising one or more amino acid, for example one or more amino acid selected from the group consisting of C, K, G and S (for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25 or 30 amino acid; and preferably 1, 2, 3, 4, 5, 6, 7, 89 or 1 amino acid 0; for example 1 to 8 amino acid, and more preferably 1 or 8 amino acid).

59. The CD16a-binding polypeptide as claimed in any preceding claim, which further comprises a further additional functional portion (for example at least one, at least two, or at least three; for example 1, 2, 3, 4 or 5 additional functional portions).

60. The CD16a-binding polypeptide as claimed in claim 59, wherein the further additional functional portion comprises an immune signalling molecule, for example a cytokine, for example IL-15 or derivatives thereof.

61. The CD16a-binding polypeptide as claimed in claim 59, wherein the further additional functional portion comprises an additional binding moiety.

62. The CD16a-binding polypeptide as claimed in claim 61, wherein the additional binding moiety is specific for a cancer cell surface target, for example a myeloma cell surface antigen, for example hBCMA, or is specific for a NK cell target.

63. The CD16a-binding polypeptide as claimed in claim 61 or claim 62, wherein the additional binding moiety is an hBCMA-binding polypeptide whichcomprises at least one motif that binds to hBCMA, wherein said hBCMA- binding polypeptide comprises the following structure: [N-terminal portion]-[Helix 1b]-[Separating portion]-[Helix 2b]-[C-terminal portion] the hBCMA binding motif being the portion [Helix 1b]-[Separating portion]- [Helix 2b].

64. The CD16a-binding polypeptide as claimed in claim 63, wherein: i) Helix 1b comprises the sequence X9X10X11ADX14EIX17X18 and Helix 2b comprises the sequence FX25QKWAFX31RX33LX35, wherein, independently from each other, X9 and X10 are any naturally occurring amino acid; X11 is E, F, H, Q, T or Y; X14 is any naturally occurring amino acid; X17 is A, E, Q, S, T or V; X18 is any naturally occurring amino acid; X25 is F or Y; X31 is I, M, or V; X33 is K or S; X35 is I, L, M, or V; or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xn are replaced by an alternative residue.

65. The CD16a-binding polypeptide as claimed in claim 64, wherein the hBCMA binding efficacy of the hBCMA-binding polypeptide is at least 1% of SEQ ID NO:

226.

66. The CD16a-binding polypeptide as claimed in claim 63, wherein:i) Helix 1b comprises the sequence X9X10X11ADX14EIX17X18 and Helix 2b comprises the sequence FX25QKWAFX31RX33LX35, wherein, independently from each other, X9 and X10 are any naturally occurring amino acid; X11 is E, F, H, Q, T or Y; X14 is any naturally occurring amino acid; X17 is A, E, Q, S, T or V; X18 is any naturally occurring amino acid; X25 is F or Y; X31 is I, M, or V; X33 is K or S; X35 is I, L, M, or V; or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 5 (for example at least 1 and no more than 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 5 (for example at least 1 and no more than 3) of the residues not labelled as Xn are replaced by an alternative residue; and wherein the hBCMA binding efficacy is at least 1% of SEQ ID NO:

226.

67. The CD16a-binding polypeptide as claimed in claim 64, wherein: i) Helix 1b comprises the sequence X9X10X11ADX14EIX17X18 and Helix 2b comprises the sequence FYQKWAFIRX33LM, wherein, independently from each other, X9 is D, E, H, K, N, Q, S, or V; X10 is A, E, F, I, K, M, N, Q, R, S, T, Y, or V; X11 is E, F, or H; X14 is A, E, H, I, K, L, Q, R, T, or Y; X17 is A, E S, T, or V; X18 is A, F, H, K, L, M, N, T, or S; X33 is K or S;or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 3 (for example 1, 2 or 3) of the Xn residues are replaced by an alternative residue, and / or at least 1 and no more than 3 (for example 1, 2 or 3) of the residues not labelled as Xn are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

68. The CD16a-binding polypeptide as claimed in claim 67, wherein the hBCMA binding efficacy of the hBCMA-binding polypeptide is at least 1% of SEQ ID NO:

226.

69. The CD16a-binding polypeptide as claimed in any one of claims 63 to 68, wherein: Helix 1b comprises the sequence X6X7X8X9X10X11ADX14EIX17X18X19, and / or Helix 2b comprises the sequence, X23FX25QKWAFX31RX33LX35X36X37, wherein, X6 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X7 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; X8 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably E) or is absent; X19 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L) or is absent; X23 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X36 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; and X37 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; and preferably wherein X6 is N; X7 is K; and X8 is E; and / or wherein X36 is D; and X37 is D;for example wherein X6 is N; X7 is K; X8 is E; X19 is L; X23 is N; X36 is D; and X37 is D.

70. The CD16a-binding polypeptide as claimed in claim 69, wherein: i) Helix 1b comprises the sequence NKEETFADLEISNL and Helix 2b comprises the sequence NFYQKWAFIRSLMDD, or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 2 (for example 1 or 2) residues are replaced by an alternative residue, or (iii) at least 1 and no more than 3 (for example 1, 2, or 3) residues in the sequence of Helix 1b and / or Helix 2b are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

71. The CD16a-binding polypeptide as claimed in claim 70, wherein the hBCMA binding efficacy of the hBCMA-binding polypeptide is at least 1% of SEQ ID NO: B1.

72. The CD16a-binding polypeptide as claimed in claim 69, wherein: i) Helix 1b comprises the sequence NKENQFADEEIAAL and Helix 2b comprises the sequence NFYQKWAFIRKLMDD, or ii) Helix 1b and Helix 2b are defined as in i), wherein within Helix 1b and Helix 2b, at least 1 and no more than 2 (for example 1 or 2) residues are replaced by an alternative residue or (iii) at least 1 and no more than 3 (for example 1, 2, or 3) residues in the sequence of Helix 1b and / or Helix 2b are replaced by an alternative residue (for example replaced by an alternative residue that is a conservative replacement).

73. The CD16a-binding polypeptide as claimed in claim 72, wherein the hBCMA binding efficacy of the hBCMA binding polypeptide is at least 1% of SEQ ID NO: 226.

74. The CD16a-binding polypeptide as claimed in any one of claims 63 to 73, wherein the separating portion of the hBCMA binding polypeptide is a sequence of 1 to 5 (preferably 2 to 5, for example 2, 3, 4 or 5; or for example 3 to 5, for example 3, 4 or 5, and more preferably 3) naturally occurring amino acids.

75. The CD16a-binding polypeptide as claimed in any one of claims 63 to 74, wherein the separating portion of the hBCMA binding polypeptide has the sequence X20X21X22, wherein X20 is any naturally occurring amino acid (preferably S, T, M, P, F, Y or W; more preferably P); X21 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N); X22 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably L); and wherein optionally one or two (for example optionally 1) of X20 , X21 or X22 are absent; and preferably wherein X20 is P; X21 is N; and X22 is L (for example, the separating portion has the sequence PNL).

76. The CD16a-binding polypeptide as claimed in any one of claims 63 to 75, wherein the N-terminal portion of the hBCMA binding polypeptide is absent or is a sequence of 1 to 15 (preferably 1 to 10 or 1 to 8, more preferably 1 to 5, for example 1, 2, 34 or 5) naturally occurring amino acids.

77. The CD16a-binding polypeptide as claimed in any one of claims 63 to 76, wherein the N-terminal portion of the hBCMA binding polypeptide has the sequence XaXbX1X2X3X4X5, wherein Xa is M or is absent; Xb is M or is absent; X1 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably V or G; most preferably V) or is absent;X2 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; X3 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X4 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; and X5 is any naturally occurring amino acid (preferably F, Y or W; more preferably F) or is absent; preferably wherein Xa is M or is absent, Xb is M or is absent, X1 is V, G or absent (preferably V or absent), X2 is D or absent, X3 is N or absent, X4 is K or absent, and X5 is F or absent.

78. The CD16a-binding polypeptide as claimed in any one of claims 63 to 77, wherein the N-terminal portion of the hBCMA binding polypeptide is absent, or the N-terminal portion of the hBCMA binding polypeptide has the sequence XaXbX1X2X3X4X5 wherein Xa is M, Xb is M, X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; or Xa is absent, Xb is absent, X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; or Xa is absent, Xb is absent, X1 is absent, X2 is D, X3 is N, X4 is K, and X5 is F; or Xa is absent, Xb is absent, X1 is absent, X2 is absent, X3 is N, X4 is K, and X5 is F; or Xa is absent, Xb is absent, X1 is absent, X2 is absent, X3 is absent, X4 is K, and X5 is F; or Xa is absent, Xb is absent, X1 is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is F.

79. The CD16a-binding polypeptide as claimed in any one of claims 63 to 78, wherein the N-terminal portion of the hBCMA binding polypeptide has the sequence X1X2X3X4X5, whereinX1 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably V or G; and most preferably V) or is absent; X2 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably D) or is absent; X3 is any naturally occurring amino acid (preferably D, E, N or Q; more preferably N) or is absent; X4 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; and X5 is any naturally occurring amino acid (preferably F, Y or W; more preferably F) or is absent; and preferably wherein X1 is V, G or absent, X2 is D or absent, X3 is N or absent, X4 is K or absent, and X5 is F or absent.

80. The CD16a-binding polypeptide as claimed in any one of claims 63 to 79, wherein the N-terminal portion of the hBCMA binding polypeptide is absent, or the N-terminal portion of the hBCMA-binding polypeptide has the sequence X1X2X3X4X5 wherein X1 is V or G (preferably V), X2 is D, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is D, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is N, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is absent, X4 is K, and X5 is F; or X1 is absent, X2 is absent, X3 is absent, X4 is absent, and X5 is F.

81. The CD16a-binding polypeptide as claimed in any one of claims 63 to 80, wherein the C-terminal portion of the hBCMA-binding polypeptide is absent or is a sequence of 1 to 50 (for example 1 to 35, 1 to 30, 15 to 25 or 18 to 22) naturally occurring amino acids.

82. The CD16a-binding polypeptide as claimed in any one of claims 63 to 81, wherein the C-terminal portion of the hBCMA-binding polypeptide has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X38 is a sequence of 1 to 14 (preferably 1 to 9 or 1 to 7, more preferably 1 to 4, for example 1, 2, 3 or 4) naturally occurring amino acids (and preferably X38 is any naturally occurring amino acid (most preferably X38 is P)), X39 is any naturally occurring amino acid (preferably S, T, M, P, F, Y or W; more preferably S), X56 is any naturally occurring amino acid (preferably G, A, V, L or I; more preferably A) or is absent, X57 is any naturally occurring amino acid (preferably P) or is absent; and X58 is any naturally occurring amino acid (preferably H, K or R; more preferably K) or is absent; (for example X38 is P; X39 is S; X56 is A or absent; X57 is P or absent; X58 is K or absent) and optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5) (preferably at least 1 and no more than 3 (for example 1, 2, or 3)) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue; and preferably optionally wherein, at least 1 and no more than 5 (for example 1, 2, 3, 4 or 5) (preferably at least 1 and no more than 3 (for example 1, 2, or 3)) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue that is a conservative replacement.

83. The CD16a-binding polypeptide as claimed in any one of claims 63 to 82, wherein the C-terminal portion of the hBCMA-binding polypeptide has the sequence X38X39QSANLLAEAKKLNDAQX56X57X58, wherein X56 is A, X57 is P, and X58 is K; X56 is A; or X57 is P, and X58 is absent; X56 is A, X57 is absent; and X58 is absent; orX56 is absent, X57 is absent, and X58 is absent. and optionally wherein, at least 1 and no more than 3 (for example 1, 2, or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue; and preferably optionally wherein, at least 1 and no more than 3 (for example 1, 2, or 3) of the residues in the sequence QSANLLAEAKKLNDAQ are replaced by an alternative residue that is a conservative replacement; and preferably wherein X38 is P and X39 is S.

84. The CD16a-binding polypeptide as claimed in any one of claims 63 to 83, wherein: (i) the separating portion of the hBCMA-binding polypeptide has the sequence X20X21X22; and / or the N-terminal portion of the hBCMA-binding polypeptide has the sequence XaXbX1X2X3X4X5 ; and / or the C-terminal portion of the hBCMA-binding polypeptide has the sequence PSQSANLLAEAKKLNDAQX56X57X58; wherein, in said separating portion of the hBCMA-binding polypeptide, X20 is P; X21 is N; X22 is L; wherein in said N-terminal portion of the hBCMA-binding polypeptide, Xa is M or absent; Xb is M or absent; X1 is V or G (preferably V), or absent; X2 is D or G, or absent; X3 is G or N, or absent; X4 is K or absent; X5 is F or absent; and wherein in said C-terminal portion of the hBCMA-binding polypeptide, X56 is A or absent; X57 is P or absent; X58 is K or absent; or (ii) the separating portion of the hBCMA-binding polypeptide, N-terminal portion of the hBCMA-binding polypeptide, and C-terminal portion of the hBCMA-binding polypeptide are as defined in (i), wherein optionally(a) within each portion 1, 2 or 3 residues are replaced by an alternative residue; or (b) within those portions taken together at least 1 and no more than 10 (for example, not more than 5, for example 1, 2, 3, 4, or 5) residues are replaced by an alternative residue.

85. The CD16a-binding polypeptide as claimed in any one of claims 63 to 84, wherein said separating portion of the hBCMA-binding polypeptide has the sequence PNL.

86. The CD16a-binding polypeptide as claimed in any one of claims 63 to 85 wherein: (i) said separating portion of the hBCMA-binding polypeptide has the sequence PNL and said hBCMA binding motif is flanked by an N-terminal portion X1X2X3X4X5 and a C-terminal portion PSQSANLLAEAKKLNDAQAPK, wherein in said N-terminal portion of the hBCMA-binding polypeptide, X1 is G, V, or deleted; X2 is D or deleted; X3 is N or deleted; X4 is K or deleted; X5 is F or deleted; or (ii) the separating portion of the hBCMA-binding polypeptide, N-terminal portion of the hBCMA-binding polypeptide, and C-terminal portion of the hBCMA-binding polypeptide are as defined in (i), wherein within those portions taken together at least 1 and no more than 5 residues are replaced by an alternative residue.

87. The CD16a-binding polypeptide as claimed in any one of claims 63 to 86, wherein said N-terminal portion of the hBCMA-binding polypeptide has the sequence VDNKF.

88. The CD16a--binding polypeptide as claimed in any of claims 74 to 85, wherein the hBCMA binding efficacy is at least 1% of SEQ ID NO:

226.

89. The CD16a-binding polypeptide as claimed in any one of claims 63 to 88, wherein the hBCMA binding motif sequence is selected from the sequences in Table B above.;preferably from the first 19 sequences in that Table; and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement;.

90. The CD16a-binding polypeptide as claimed in claim 63 or claim 64, which comprises an hBCMA binding polypeptide sequence selected from SEQ ID Nos: B1 or 226, or a sequence in Table A herein from the sequence referred to as 1-E1 in the Table to the sequence referred to as to 2-D10, from the sequence referred to as 1-A2 in the Table to the sequence referred to as to 2- B7, or from the sequence referred to as 2-F6 in the Table to the sequence referred to as to 2-F11 and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement; or the CD16a-binding polypeptide as claimed in claim 63 or claim 64, which comprises an hBCMA binding polypeptide sequence selected from SEQ ID NOs. 226 and a sequence in Table A herein from the sequence referred to as 1- E1 in the Table to the sequence referred to as to 2-D10, and wherein optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue, and preferably optionally from 1 to 5 (preferably 1, 2 or 3) residues in the sequence are replaced by an alternative residue that is a conservative replacement.

91. The CD16a-binding polypeptide as claimed in claim 63 or claim 64, wherein the sequence of the hBCMA-binding polypeptide is selected from: VDNKFNKEETFADLEISNLPNLNFYQKWAFIRSLMDDPSQSANLLAEA KKLNDAQAPK [SEQ ID NO: B1]; or VDNKFNKENQFADEEIAALPNLNFYQKWAFIRKLMDDPSQSANLLAE AKKLNDAQAPK [SEQ ID NO: 226]; or VDNKFNKEEIFADREIAFLPNLNFYQKWAFIRKLMDDPSQSANLLAEA KKLNDAQAPK [1-E1 in Table A]; orVDNKFNKEHQFADYEIAMLPNLNFYQKWAFIRSLMDDPSQSANLLAE AKKLNDAQAPK [2-E5 in Table A].

92. The CD16a-binding polypeptide as claimed in claim 63 or claim 64, wherein the sequence of the hBCMA-binding polypeptide is selected from the sequences in Table A herein from the sequence referred to as 1-E1 in the Table to the sequence referred to as to 2-D10.

93. The CD16a-binding polypeptide as claimed in any one of claims 63 to 92, wherein the hBCMA-binding polypeptide does not comprise methionine.

94. The CD16a-binding polypeptide as claimed in claim 63, wherein the sequence of the hBCMA binding polypeptide is as defined in any one of claims 64 to 92, wherein, at a position at which a methionine residue is recited, the polypeptide has the sequence with the methionine residue independently substituted for a different naturally occurring amino acid or an unnatural amino acid (for example a different naturally occurring amino acid or norleucine); and preferably each methionine residue is independently substituted for an amino acid selected from isoleucine (I), leucine (L), glutamine (Q), norleucine, homoleucine and tert- butylalanine; and more preferably each methionine residue is independently substituted for a norleucine or isoleucine.

95. The CD16a-binding polypeptide as claimed in any one of claims 63 to 94, wherein one or more residues (for example 1 to 5 residues, for example 1, 2 ,3, 4 or 5) of the hBCMA-binding polypeptide is / are substituted for an unnatural amino acid, for example norleucine; and / or wherein one or more methionine residues of the hBCMA-binding polypeptide, when present (for example 1 or 2 methionine residue(s) when present), is / are substituted for an unnatural amino acid, for example norleucine;and / or wherein one or more leucine residues of the hBCMA-binding polypeptide, when present (for example 1 to 5 leucine residues, when present), is / are substituted for norleucine; and / or wherein one or more methionine residues of the hBCMA-binding polypeptide, when present (for example 1 or 2 methionine residue(s) when present), is / are oxidised (for example is / are Met(O)).

96. A CD16a-binding polypeptide which comprises at least one motif that binds to CD16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]- [Helix 2], wherein the sequence of the CD-16a-binding motif is selected from SEQ ID NOs 1014 to 1026 and 1044.

97. A CD16a-binding polypeptide which comprises at least one motif that binds to CD16a, wherein said polypeptide comprises the following structure: [N-terminal portion]-[Helix 1]-[Separating portion]-[Helix 2]-[C-terminal portion], the CD16a-binding motif being the portion [Helix 1]-[Separating portion]- [Helix 2], wherein the sequence of the CD16a-binding polypeptide is selected from SEQ ID NOs: 1001 to 1013 and 1043.

98. A pharmaceutical composition comprising a CD16a-binding polypeptide according to any one of claims 1 to 95.

99. A CD16a-binding polypeptide according to any one of claims 1 to 95 or a pharmaceutical composition according to claim 98 for use as a medicament.

100. A CD16a-binding polypeptide for use according to claim 99 wherein the medicament is for use in the treatment and / or prophylaxis of cancer.

101. A CD16a-binding polypeptide for use according to claim 100 wherein the medicament is for use in the treatment and / or prophylaxis of multiple myeloma.

102. Use of a CD16a-binding polypeptide according to any one of claims 1 to 95 or a pharmaceutical composition according to claim 99 in the manufacture of a medicament for the treatment and / or prophylaxis of cancer.

103. Use according to claim 102 wherein the medicament is for the treatment and / or prophylaxis of multiple myeloma.

104. A method of treating cancer, the method comprising administering to a patient in need thereof a CD16a-binding polypeptide according to any one of claims 1 to 95 or a pharmaceutical composition according to claim 99.

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