Novel immunoconjugates

Abstract

This invention relates to immunoconjugates, particularly immunoconjugates comprising an antibody or antigen-binding fragment thereof comprising a first antibody binding domain that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof, and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof. The invention also relates to immunoconjugates comprising a multispecific antibody or antigen-binding fragment thereof which further comprises a second antibody binding domain that specifically binds to a second, different target antigen than the first antibody binding domain, such as a tumor associated antigen (TAA). Additionally, this invention relates to polynucleotide molecules encoding said immunoconjugates. It also relates to vectors containing such polynucleotides and host cells comprising such polynucleotides and methods of producing said immunoconjugates. The invention also relates to methods using said immunoconjugates, such as methods treating disease using said immunoconjugates and medicaments comprising or derived from said immunoconjugates.

Description

[0001] NOVEL IMMUNOCONJUGATES

[0002] FIELD OF THE INVENTION

[0003] In general, this invention relates to immunoconjugates, particularly immunoconjugates comprising an antibody or antigen-binding fragment thereof comprising a first antibody binding domain that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof, and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof. The invention also relates to immunoconjugates comprising a multispecific antibody or antigen-binding fragment thereof which further comprises a second antibody binding domain that specifically binds to a second, different target antigen than the first antibody binding domain, such as a tumor associated antigen (TAA). Additionally, this invention relates to polynucleotide molecules encoding said immunoconjugates. It also relates to vectors containing such polynucleotides and host cells comprising such polynucleotides and methods of producing said immunoconjugates. The invention also relates to methods using said immunoconjugates, such as methods treating disease using said immunoconjugates and medicaments comprising or derived from said immunoconjugates.

[0004] BACKGROUND

[0005] Gamma Delta T cell and T-cell receptor Classification

[0006] Human gamma (g) delta (d) T-cell Receptors (gamma delta TCRs) are heterodimeric receptors comprising a gamma chain and a delta chain. Conventionally this class of receptors is classified into sub-groups (sub-classes or sub-types) dependent on variable domain usage and the associated functionality / residency of gamma delta cells expressing said receptors.

[0007] For example, one common classification system involves classifying the receptors via variable chain usage which can be summarized as follows:

[0008] Classification of receptor via variable chain usage:

[0009] Human gamma delta TCRs containing a variable delta-one chain are often termed "delta-one" or "dl" or "VD1" TCRs as they comprise gamma delta TCRs encoded in part by the TRDV1 gene and comprise TRDV1 protein sequence. Typically, delta-one TCRs are predominantly expressed on gamma delta cells found in tissues and as such, cells positive for the delta-one TCR are sometimes termed 'tissueresident' gamma delta T cells. Human gamma delta TCRs containing a variable delta-two chain are often termed "delta-two" or "d2" or "VD2" TCRs as they comprise gamma delta TCRs encoded in part by the TRDV2 gene and comprise TRDV2 protein sequence. Typically, delta-two TCRs are predominantly expressed on gamma delta cells found in blood and as such, cells positive for the delta-two TCR are sometimes termed 'blood-derived' gamma delta T cells.

[0010] Human gamma delta TCRs containing a variable delta-three chain are often termed "delta-three" or "d3" or "VD3" TCRs as they comprise gamma delta TCRs encoded in part by the TRDV3 gene and thus comprise TRDV3 protein sequence. Delta-three TCRs are less well-studied and can be expressed on a smaller population of gamma delta T cells. They are likely a mixture of blood and tissue-resident (see also 'non-delta two' classification below).

[0011] Additional to the above delta-one, delta-two and delta-three receptor sub-classes, there are a number of 'other' human gamma-delta receptors; specifically "delta-four" or "d4" or "VD4" TCRs, "delta-five" or "d5" or "VD5" TCRs, "delta-six" or "d6" or "VD6" TCRs, "delta-seven" or "d7" or "VD7" TCRs, "deltaeight" or "d8" or "VD8" TCRs. Conventionally these 'other' classes are not considered 'true' gammadelta variable domains as they are also shared with alpha-beta TCRs. Additionally, the numbers of gamma delta cells expressing gamma delta TCRs containing VD4, VD5, VD6, VD7, and VD8 are typically small.

[0012] Alongside the above classification, a more simplified classification system splits all gamma delta cells between one of only two categories; those cells expressing delta-two TCRs and those which do not. In this approach gamma delta cells not expressing delta-two TCRs are termed 'non-delta two' gamma delta cells or 'non-haematopoietic tissue-resident' gamma delta cells (e.g. WO2017072367A1). In essence this classification approach is in recognition of the fact that in blood, the predominant class of cells are positive for delta-two containing TCRs cells whereas 'non-delta two' gamma delta cells predominate elsewhere (in tissues etc).

[0013] Finally, another somewhat enigmatic classification system defines one populations of gamma delta cells purely by what they are not - specifically gamma delta cells which are 'non delta-one and non delta-two' gamma delta cells have been classified as a single group previously (e.g. see Deniger et al Clin Cancer Res. 2014 Nov 15;20(22):5708-19. doi: 10.1158 / 1078-0432. CCR-13-3451). One might assume this class of cells is therefore instead positive for TCR delta-three, delta-four, delta-five, delta-six, delta-seven, and / or delta-eight. An alternate way by which gamma delta TCRs and cells expressing said receptors are classified has been through their gamma-chain usage. Whilst there are at least 14 variable gamma genes (TRGV) it is assumed that only eight of these variable genes are functional. These belong to four different structural subgroups. However, only those sub-groups for which marked functional / residency differences are noted will be discussed below.

[0014] Human gamma delta TCRs containing a variable-four gamma chain are termed "gamma-four" or "g4" or "VG4" TCRs as they as they comprise gamma delta TCRs encoded in part by the TRGV4 gene and comprise TRGV4 protein sequence. This sub-class of TCR is of particular interest because cells expressing atypical levels or activity of gamma-four TCR can be associated with human gut inflammation.

[0015] Human gamma delta TCRs containing a variable-nine gamma chain are sometimes termed "gamma-nine" or "g9" or "VG9" TCRs as they as they comprise gamma delta TCRs encoded in part by the TRGV9 gene and comprise TRGV9 protein sequence. This sub-class of TCR is of particular interest because cells expressing gamma-nine TCRs often present as a heterodimeric complex with delta-two chains and as such typically predominate in blood.

[0016] Finally, it must be noted that the above example classification systems are not absolute and indeed there is overlap. For example, and as already mentioned, gamma-nine TCR positive cells are often delta-two TCR positive too.

[0017] New classification of receptor via constant chain usage:

[0018] However often overlooked is the fact that all such gamma delta TCR comprise one of two variant heterodimeric constant domains. The present inventors therefore propose an alternate approach to classifying both the gamma delta TCRs themselves as well as the cells expressing such TCRs.

[0019] In humans, the delta chain constant domain of a gamma delta receptor is encoded by a single human TRDC gene and as such all gamma delta TCRs contains human TRDC protein sequence - termed T-cell receptor constant protein (e.g. see Uniprot B7Z8K6; TRDC_HUMAN) (SEQ ID NO: 1).

[0020] By contrast the human gamma constant chain of a gamma delta receptor is encoded by either;

[0021] (i) the human TRGC1 gene and as such will contain the human TRGC1 protein - termed T-cell receptor constant protein 1 (see Uniprot P0CF51; TRGC1_HUMAN) (SEQ ID NO: 2) or; (ii) the human TRGC2 gene and as such contain the human TRGC2 protein - termed T-cell receptor constant protein 2 (see Uniprot P03986; TRGC2_HUMAN) (SEQ ID NO: 3)

[0022] Hence rather than classifying all gamma delta T cell sub-types by variable domain usage, one could instead consider classifying such receptors by constant domain usage. In doing so it is thus possible to divide all gamma delta cells into one of only 2 alternate sub-types as follows.

[0023] Human "GC1" receptors and cells expressing GC1 receptors

[0024] This gamma delta TCR sub-class comprises TCRs containing the TRDC and TRGC1 constant domains. Hence it is proposed herein that TCRs of this sub-class are termed "GC1" TCRs. As such gamma delta cells expressing this sub-class of TCR can thus be abbreviated to "GC1" positive gamma delta cells.

[0025] Human "GC2" receptors and cells expressing GC2 receptors

[0026] This gamma delta TCR sub-class comprises TCRs containing the TRDC and TRGC2 constant domains. Hence it is proposed herein that TCRs of this sub-class are termed "GC2" TCRs and as such gamma delta cells expressing this sub-class of TCR can thus be abbreviated to "GC2" positive gamma delta cells.

[0027] Whilst defining such cells in this manner is thus a novel possibility, without antibody tools able to distinguish these two sub-groups clearly and reliably it is little more than a theoretical academic exercise in most circumstances. Hence there is a need for better, more selective antibodies.

[0028] One notable challenge in the provision of antigen tools to aid with discovery of antibodies capable of selectively recognizing and binding GC1 and / or GC2 TCRs are the respective TRGC1 and TRGC2 constant domains. Whilst both human TRGC1 and TRGC2 domains share >90% amino acid sequence homology, they differ in marked and unique ways not observed in constant domains of conventional alpha beta TCRs. Specifically, whilst gamma delta GC1 TCRs comprising TRDC / TRGC1 heterodimers contain a canonical single interchain disulfide linkage, the GC2 TCRs comprise TRDC / TRGC2 heterodimers contains no such interchain disulfide linkage. This is unique amongst human T-cell Receptors and is because the TRGC2 gene segment contains no partner cysteine to pair with the cysteine present on cognate TRDC domains. Instead for the TRGC2 domain, this cysteine is replaced by a bulky hydrophobic tryptophan (Trp133, SEQ ID NO: 12) as shown in Figure 4. Alongside this atypical 'missing' interchain linkage, the TRGC2 constant domain is also larger, exhibits multiply sized isoforms, and exhibits differing N-linked glycosylation patterning. The resulting differences in GC1 and GC2 TCR architectures makes the design and provision of authentic and representative antigens more challenging.

[0029] To summarize further, a comparison of the GC1 and GC2 TCRs is presented below in Table 1.

[0030] TABLE 1

[0031] TCR Feature GC1 TCRs GC2 TCRs

[0032] Overall Size Smaller relative to GC2 Multiple allelic variants, all larger than GC1

[0033] TRGC 'Connecting' Smaller relative to TRGC2 Larger relative to TRGC1 and due to at Region least one additional insert (or multiple inserts dependent on the allele)

[0034] TRGC cysteine Yes, TRGC1 (Cys121; Uniprot No, cysteine replaced with a bulky employed in numbering of TRGC1_Human aromatic acid (Trpl37; Uniprot interchain pairing P0CF51 (SEQ. ID NO: 2; also see numbering of TRGC2_Human P03986

[0035] Cys117 SEQ ID NO:11) SEQ ID NO: 3, also see Trp133 SEQ ID 12 )

[0036] TRDC cysteine 110 is Yes No, instead it appears 'orphaned' paired

[0037] Inter-chain disulfide Yes No

[0038] bond formed between

[0039] TRDC and TRGC

[0040] heterodimer

[0041] Potential TRDC 2 sites (N14 and N77 TRDC SEQ 2 Sites (N14 and N77 TRDC SEQ ID glycosylation sites ID NO: 1) NO: 1)

[0042] Potential TRGC N- Four sites (N66, N120, N126, Five Sites (N66, N120, N136, N142, linked Glycosylation N135 Uniprot numbering of N151, Uniprot numbering of

[0043] Sites (and positions) TRGClJHuman P0CF51 SEQ ID TRGC2_Human P03986 SEQ ID NO: 3)

[0044] NO: 2)

[0045] Therapeutic Human Monoclonal antibodies selective for specific Gamma Delta TCRs.

[0046] To date, a number of discovery projects have been undertaken primarily to identify and isolate human or humanized therapeutic antibodies capable of binding and / or modulating and / or depleting and / or activating cells expressing gamma delta TCRs. Typically, such discovery projects have focused on the discovery and use of antibodies as medicaments to selectively activate specific sub-sets of gamma delta cells such to ameliorate signs and symptoms of diseases including cancers and infections. Example of such projects are summarized in Table 2 below.

[0047] TABLE 2

[0048] Sub-Class of Example Project Possible use? Possible Advantages? gamma delta

[0049] TCR targeted by

[0050] antibody-based

[0051] moieties

[0052] Gamma nine WO2015156673 and de Medical treatment for the Targeting and Bruin et al 2018 treatment of cancer or an activation of gamma- Oncoimmunology; 7(1): infectious disease nine TCR positive cells el375641 doi: predominantly found 10.1080 / 2162402X.2017.137 in blood

[0053] 5641

[0054] Gamma four W02021171002 Pharmaceutical Targeting and composition for the activation of gamma treatment of disease four TCR positive cells often displaying markers of gut tissue residency

[0055] Delta one W02021032960 Pharmaceutical Targeting and composition for the activation of 'tissuetreatment of disease resident' delta-one TCR positive cells Delta one WO2019147735 Medicament for use in Inhibiting the treating diseases activation of gamma delta T cells Delta two WO2015156673 and de Medical treatment for the Targeting and Bruin et al 2018 treatment of cancer or an activation of delta-two Oncoimmunology; 7(1): infectious disease el375641 doi: TCR positive cells in 10.1080 / 2162402X.2017.137 blood

[0056] 5641

[0057] Delta three WO 2019099744 For creating Ex-vivo enrichment of pharmaceutical delta-three TCR composition comprising positive subset delta-three enriched

[0058] gamma delta cells for the

[0059] treatment of conditions

[0060] including cancer and

[0061] infectious diseases

[0062] The use of antibodies as medicaments to modulate specific gamma delta T cells

[0063] As outlined in Table 2, various strategies have been undertaken to date focused on the discovery of antibodies which selectively bind to, target, and / or modulate (typically through activation) certain subsets of gamma delta T cells. Associated with such strategies, those skilled-in-the-art have typically outlined that the sub-set of gamma delta T cells they are activating is likely the most preferred subtype. For example, it has been suggested that antibodies which selectively target and activate delta-two TCR positive cells are most desirable because (i) delta-two positive cells comprise 90-95% of peripheral blood gamma delta T cells; (ii) they consistently generate a pro-inflammatory cytotoxic T cell population; (iii) they are able to present antigen and (iv) they are associated with good prognosis in cancer patients. In contrast, it is suggested that targeting the other major sub-set of gamma delta cells - namely the delta-one cell sub-set - is less desirable given (i) delta-one cells are infrequently present in blood and (ii) delta-one cells exhibit more variable prognosis profiles.

[0064] However, other artisans suggest the converse - specifically that delta-one cells are a more preferred sub-set to activate and to use in the treatment of cancer. For example, some authors suggest that delta-one cells may be preferred whereas delta-two cells are (i) dysfunctional in some cancer patients and (ii) susceptible to activation induced anergy and exhaustion.

[0065] Finally, some investigators suggest that gamma delta cells are in fact undesirable and should be depleted rather than selectively activated during cancer treatment regimens. Indeed, these researchers - some associated with Nybo Therapeutics Inc (Boston, MA, USA) - consider killing or depleting gamma delta cells, particularly delta-one TCR positive cells, as the best option and propose the use of selective antibodies to mediate dependent cellular cytotoxicity (ADCC) based depletion of gamma delta cells accordingly. This is because these investigators consider gamma delta cells, and more specifically delta-one TCR positive gamma delta cells, to be immunosuppressive, particularly in pancreatic cancer.

[0066] Alongside example antibody clinical trials as outlined above in Table 2, to date there have also been a significant number of example cell therapy products wherein delta two or delta one enriched populations of cells have been used as cell therapy medicaments. Such cell therapies typically comprise hundreds of millions of gamma delta cells per dose. Such medicines are highly complex, costly to develop, store, distributed and administer - particularly to large numbers of patients. Hence there is a need for ways and means to increase the number of gamma delta cells in a patient in need of treatment without the need for such complex cell therapies.

[0067] In summary, during the pursuit of antibody-based medicaments and cell therapies designed to harness gamma delta T cells, numerous alternative strategies have been explored and described at length to date.

[0068] The need for "pan-gd" medicines

[0069] Whilst it is possible that all such approaches for the use of antibodies as medicaments to modulate specific gamma delta T cells have merit, there is clearly a need to better understand and characterize this class of medicaments. Many approaches to date are narrow in focus which may result in less effective antibody medicaments. In many circumstances a selective, partisan choice of one sub-type of gamma delta cells to target is not always optimal since it ignores potential holistic benefits of activating multiple sub-classes of gamma delta cells. There is therefore a need for antibodies that are capable of recognising and binding specifically and selectively to multiple sub-classes of gamma delta TCR (termed a "pan gamma delta" or "pan gd" antibody). One way of achieving this is via one or more constant domains of a gdTCR. Such antibodies are not restricted to binding only one sub-class of gamma delta TCR (for example a delta-one TCR) but can bind to multiple sub-classes of gamma delta TCR (for example delta-one, delta-two and delta-three TCRs).

[0070] For instance, researchers focused on the discovery of antibody-based medicaments selective for delta-one gamma delta cells with a more tissue-resident distribution may then consider use of such medicaments to ameliorate the signs and symptoms of tissue-derived cancers -so called solid tumors. However, such antibody-based medicaments may prove sub-optimal for this purpose as they do not also target delta-three cells also reportedly present in tissues - and sometimes in greater numbers. Therefore antibody-based medicaments capable of activating both classes could be used to underpin more holistic treatment regimens wherein both blood and tissue resident gamma delta cells are activated resulting in a more systemic surveillance of both blood and tissue.

[0071] As another example, other investigators with a preference for developing antibodies specifically designed to activate blood-centric gamma-nine gamma delta cells may then focus on their use in the treatment of leukaemia or so called 'liquid' tumors of the blood and where delta-two gamma delta cells predominate. However primary liquid tumors of the blood can develop via metastasis to become secondary tissue / solid tumors where gamma-nine gamma delta cells are less prevalent. In this instance, and once again, an ideal antibody-based medicaments might be one that is not only capable of selectively activating blood-centric gamma nine cells but also tissue-resident delta-one cells. Once again, treatment of cancer with such medicaments may better ensure a more holistic, systemic activation of gamma delta cells and enhanced, systemic tumor surveillance.

[0072] The same point can also be made when considering antibodies designed to selectively activate gut resident gamma-four TCR positive gd-cells. For example, primary tumors of the gut metastasize to other tissues often via the blood and lymphatic system. Hence once again an ideal antibody-based medicament is one capable of activating more than just gut-resident, gamma-four TCR positive gamma delta cells.

[0073] To discover and fully characterise such antibody-based medicaments capable of selectively target multiple sub-classes of gd cells and induce proliferation in all sub-classes of gamma delta T cells - be they the delta one, delta two or delta three sub-class, a novel suite of antigens was developed.

[0074] These antibodies and antibody-based medicaments exhibit desirable characteristics and technical effects which enable better treatment of patients, providing engagers to enhance and direct the power of key cells of the innate and adaptive immune system, opening up attractive targets unsuitable for CD3 based engagers. Through the recognition of antigens common to multiple classes of gamma delta T cells these antibodies and antibody-based medicaments exhibit features which can be leveraged to aid with more effective dosing regimens, more real-time patient monitoring, patient response and responsiveness rates, alongside improved patient stratification regimens. These antibodies can also be employed as superior tools to better understand the biology and character of gamma delta T cells and sub-classes thereof. The novel approaches, methods, and treatment regimens thereby conceptualized by the availability and characterization of these novel antibodies are also provided herein.

[0075] Anti-gamma delta TCR antibody based medicaments; measuring target engagement and accurately characterizing conferred effects.

[0076] As outlined above, a variety of differing antibody-based medicaments targeting gamma delta TCRs have been prioritized and progressed to the clinic. To the best of our knowledge all such medicaments in clinical development to date selectively bind and target a variable domain as summarized above. However, one seemingly overlooked consideration in developing such medicaments is the need to optimally characterize and measure gamma delta TCR target engagement and conferred functional effects. There is a need for better medicines and better methods to monitor gamma delta TCR engagement, in particular when targeting tissue resident gamma delta cells.

[0077] This need is particularly pressing in human and primate studies as this group of mammals are defined as 'gamma delta low' species (<5% of lymphocytes in blood). In contrast, certain other mammals such as ruminants are sometimes termed 'gamma delta high' species given significantly higher numbers (15%-60%) observed in immune compartments.

[0078] Consequently, whilst these cells are often considered fundamentally important for immune surveillance and catalysis, they form a very small number of immune cells in human blood. Furthermore, within the blood, the numbers of delta one positive and delta three positive gamma delta are even lower given their tissue preference / residency. Hence developing medicines which may target and activate delta one and delta three cells may be desirable but the very small numbers of delta one and delta three cells in blood make clinical development and patient triaging more challenging. In such situations perhaps the only alternative option is to measure effects via complex tissue biopsy which is highly invasive.

[0079] For further example and as described above, certain medicaments are known which selectively target and modulate gamma delta cells expressing TRDV1 (delta one, VD1) containing TCRs. This class of gamma delta cells are often found in tissues and solid tumors. When developing such antibodies as medicines one essential requirement during clinical development is the ability to characterize and model target receptor engagement, occupancy and conferred technical effects. The industry-wide challenges in this space are manyfold but these challenges are further amplified given the predominant tissue-resident nature of delta one TCR expressing cells. For example, measuring target engagement and conferred effects of predominantly tissue resident immune cells is difficult without invasive, error prone, and time-consuming tissue biopsy. This is further confounded by the requirement to ship the resected and often labile biopsied tissue samples to specialized laboratories for further processing. Additionally, given the anticipated rapid effects of antibody target engagement - such as TCR downregulation - one may be unable to accurately measure target engagement in such tissue biopsies as the target cells become 'invisible'. As a consequence, it may be very difficult to determine optimal dosing regimens, patient response rates and treatment regimens, or characterize cause-and-effect mechanisms of action of such medicaments.

[0080] In sum, developing effective patient regimens with antibody medicaments which engage tissue prominent or resident delta one or delta three gamma delta TCR positive cells in 'gamma delta low' environment is very difficult given the smaller numbers of cells for analysis in the blood. Consequently, leveraging most desired and most robust 'liquid biopsy' strategies to aid guide treatment regimens may not be possible. Further, given TCR downregulation will further hamper an ability to detect target engagement of already small population better medicines are needed which are able to engage tissue resident cells alongside more prominent blood cells more readily measured and monitored.

[0081] IL-15 pan-γδ immunoconjugates

[0082] By discovering human antibodies medicaments that specifically bind the constant domain of gamma delta T-cells we are now able to target delta one, delta two and delta three gamma delta T-cell rather than a smaller subset of such cells. Next, we conceived that we may be able to exploit such anti-gamma delta TCR constant domain antibodies to deliver a desired payload specifically to all gamma delta cells inclusive of delta one, delta two and delta three TCR positive cells. Described herein are immunoconjugates comprising an antibody which targets the constant domain of the gamma delta TCR as described herein then linked to an IL-15 component (which comprises at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and may optionally further comprise an IL-15 cytokine). The resulting immunoconjugate can therefore deliver said IL-15 component to all gamma delta cells including delta one, delta two and delta three T-cell populations.

[0083] Human Interleukin-15 is a four-helix bundle cytokine first described as a T-cell proliferation factor. It is constitutively expressed by many types of cells such as macrophages, monocytes, dendritic cells (DCs), T-cells, as well as epithelial cells, fibroblasts, keratinocytes, and nerve cells. IL-15 is involved in lymphocyte and NK cell functioning. It signals through a hetero-trimeric receptor which consist of three subunits, the IL-15 receptor α (IL-5Rα or CD215) specific subunit, IL2 / IL-15 receptor β subunit (IL2 / IL-15Rβ; CD122), and y (CD132) subunit which is a common chain for other cytokines including IL-1, IL-4, IL-7, IL-9, and IL-21. However, whilst IL-15 has shown considerable promise as a therapy there remain significant challenges associated with it due to its general toxicity and inflammatory capacity. For example, Isvoranu et al 2021 (Exp. And Therapeutic Medicine 22: 675) define what they term the ‘dark side’ of IL-15 and conclude that one of the main challenges associated with the use of IL-15 polypeptide-based medicaments for cancer immunotherapy remains maximizing tumour response whilst limiting toxicity.

[0084] Previously, a class of novel IL-15 immunoconjugates was described in PCT / EP2024 / 053368, which is incorporated for reference in its entirety herein. Further background regarding IL-15 cytokines, IL-15 polypeptides, IL-15 "superagonists" and stress-sensing receptors expressed on gamma delta T-cells is also described in PCT / EP2024 / 053368 and incorporated by reference herein.

[0085] We conceived that immunoconjugates in which the IL-15 component is fused to an anti-constant domain antibody will result in a more targeted delivery of IL-15 specifically to gamma delta T-cells and thereby preferentially activate gamma delta T-cells. We conceived this may be an ideal way to target IL-15 to the most desired locations given the cancer and tissue centric profiles associated with gamma delta T-cells. We also included the IL-15 receptor alpha sushi domain in the IL-15 component. Inclusion of a CD215 sushi domain provides additional advantages. This is because the sushi domain will bind the co-joined IL-15 cytokine and in turn "present" the IL-15 cytokine to CD122 / CD132 receptor complexes. Further through sushi domain binding of the co-joined IL-15 cytokine, the immunoconjugate is prebound to CD215 sushi domain and so no longer able to bind IL-15 receptor alpha expressed on many cell types less relevant to cancer immunology

[0086] IL-15 muteins

[0087] One of the main challenges associated with the use of IL-15 polypeptide-based medicaments for cancer immunotherapy remains maximizing tumour response whilst limiting toxicity. Some groups have focused on disabling, disrupting or impairing function of IL-15 in a variety of ways. Such approaches generate a different class of IL-15 muteins that partially block, disable, deactivate or disrupt full wild-type functionality of the cytokine and / or binding to one or more of the CD215, CD122 and CD132 receptor component parts. Non-limiting examples include those reported by Bernard et al 2004 (doi.org / 10.1074 / jbc. M312458200) and Quemener et al 2020 (doi.org / 10.1074 / jbc. M312458200) such as D8S, L45D, E46K, L47D, S58K, N65K, L66D, L66E. And one example disabling mutein studied in depth contains the Q108E mutation e.g. see Yu et al (2019, WO2019173832A2). For example, therein, the focus is on reducing the activity of the IL-15 with aid of masking peptides alongside mutations such as Q108E which can reduce biological activity by at least 5 times through to at least 100 times. Of further relevance, and prior to this, Kim et al 1998; J Immunol.

[0088] 160(12): 5742–5748 also mutated IL-15 at position Q108D alongside Q101D to create antagonistic IL-15 mutants that inhibits stimulatory and proliferative effects conferred by IL-15. Said muteins were so designed to block delayed-type hypersensitive responses. Alternative approaches to impacting IL-15 functionality include mutations to cysteines – typically cysteines form structurally important disulfide bridges. In another example, an IL-15 molecule termed Xmab24306 (e.g. see W02018071918A1) an IL-15 cytokine is described which comprises three mutations designed to dial down IL-15 cytokine affinity to certain but not all IL-15 receptors. Specifically, in this case the IL-15 cytokine was mutated as follows; D30N, E64Q, N65D. This resulted in a final mutein cytokine which exhibited markedly reduced affinity to CD122 and / or CD132. Such reduced affinity mutations differ from those described in which IL-15 moieties are mutated to create dominant negatives or to attenuate functionality (e.g. by eliminating detectable binding to CD215 as described in WO2019166946A1).

[0089] Hence there remains need for improved, more targeted IL-15-based medicaments.

[0090] Gamma delta T cells; ADCC, AIDC and non-ADCC mediated killing

[0091] Antibody-Dependent Cellular Cytotoxicity (ADCC) refers to a cell-mediated killing reaction whereby cytotoxic immune cells expressing IgG-Fc-receptor (FcyR or abbreviated to FcR herein) recognize and bind to the Fc domain of antibodies. The variable domain of said antibodies is free to recognise and bind to a target antigen expressed on a target cell. Upon such binding, Fc receptor signalling pathways of the cytotoxic immune cell are activated, resulting in immune cell activation and lysis of the target cell via an 'immunological synapse' bridge between the Fc receptor / antibody Fc domain on the immune cell and the variable domain of the antibody bound to the target present on the cell to be killed.

[0092] It is well established that gamma delta T cells are highly effective at ADCC mediated killing of target cells. It is known gamma delta T-cell killing can be mediated by ADCC using both monospecific and bispecific antibodies targeting one or two antigens. In such examples the Fc domain of the antibody binds the gamma delta T-cell FcR (e.g. CD16) and triggers FcR activation, whilst the variable domain or domains bind the target antigens. Conversely, it has previously been proposed that tool (e.g. rodent-derived) antibodies targeting the constant domain of gamma delta T cells actually induce gamma delta T-cell death (see Dutta et al 2017 "Apoptosis Induced via Gamma Delta T Cell Antigen Receptor "Blocking" Antibodies: A Cautionary Tale" Front Immunol. 2017; 8: 776. doi: 10.3389 / fimmu.2017.00776). Given this finding, one might imagine anti-gamma delta TCR constant domain antibodies may be most useful for situations in which killing a gamma delta T cell is desired, such as targeting Gamma delta (y6) T-cell acute lymphoblastic leukemia / lymphoma (T-ALL). In such situations the TCR target can be considered a TAA (tumor associated antigen) and killing of the diseased T-ALL cells can be mediated via either activation induced cell death and / or by ADCC mediated effector cell 'fratricide' wherein two effector cells engage and kill one another via antibody mediated ADCC.

[0093] It remains unclear if one can replace ADCC mediated killing with antibodies which instead engage the gamma delta T cell by selectively binding to the constant domain of the TCR in order to mediate killing of target cells by non-ADCC mechanisms. Although therapeutics that exploit ADCC can be useful, there are also downsides associated with such mechanisms, for example the possibility of off-target effects. In some situations, an antibody may bind to a healthy cell instead of a target cell (since antigens are often expressed on multiple cell types), causing lysis of healthy cells once ADCC pathways are activated. Additionally, binding of Fc to FcR leads to activation of immune cells, which can lead to further off-target toxicity when activated immune cells kill innocent "bystander" cells as well as target cells. Additionally, reducing the FcR binding properties of antibodies helps to avoid effector cell to effector cell fratricide whereby NK cell or gamma delta T-cells kill other gamma-delta T-cells which are bound by the human anti-constant domain antibody - as provided herein - by ADCC mediated reaction.

[0094] The ADCC reaction is mediated by the effector cell FcR binding to the Fc domain of the antibody. For recombinant human antibodies, there are a number of established ways to reduce the Fc domain binding to the FcR to reduce or disable ADCC functionality and prevent antibody mediated ADCC cytotoxicity toward the target cell.

[0095] Figure 20 herein further outlines the distinctions between (i) antibody mediated killing via classical ADCC reactions mediated by FcR engagement of the gamma delta T-cell (ii) Activation induced cell death (AICD) reactions mediated by Fab variable domain engagement of the gamma delta effector T-cell and (iii) non-conventional, non-ADCC reactions mediated by antibody Fab variable domain engagement of the gamma delta effector cells wherein gamma delta T-cell FcR is not engaged. One class of antibodies, of interest as components of immunoconjugates, are termed bispecific antibodies. Such antibodies can be employed to engage two targets. One approach employs bispecific antibody wherein a first antibody binding arms targets a CD3+ T-cell, and second antibody binding arm targets a disease associated antigen (DAA) or tumour associated antigen (TAA) present on a diseased or cancerous cell. Such antibodies are sometimes termed T-cell bispecific engagers. For example, conventional anti-CD3 T-cell bispecific engagers are designed such that the first binding arm binds the accessible CD3 component of the CD3 / TCR complex present on T-cells and the second binding arm binds a DAA or TAA target. Said bispecific antibody engagers then mediate the co-joining of the T-cell to the target DAA or TAA positive cell and the killing of said target cell by the T-cell. However, current T-cell bispecific engagers such as these CD3 engagers are typically sub-optimal (e.g see Singh, A. et al (2021) doi.org / 10.1038 / s41416-020-01225-5). For example, there are often significant side-effects associated with these molecules. This has resulted in numerous such engager programs being terminated during non-clinical or clinical development. One reason for such failures is because CD3 bispecific engager can engage all T-cells (CD8, CD4, T-regs, etc.) and this can result in over-activation of the immune system and result in elevated treatment-related adverse events (AE). Some of these AEs may manifest in T-cell exhaustion and / or acute cytokine flares such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Cytokines associated with CRS include IL-2, IL-6, IL-10, IL-17A. Extremely elevated levels of cytokines can have unwanted gross effects on the immune system. Further, certain such cytokines may exhibit uniquely undesirable effects. For example, high levels of IL-17A are associated with B-cell pathogenesis in autoimmune diseases (see Koga et al 2021 doi.org / 10.3389 / fimmu.2020.624971). IL-17A is also implicated in cancer progression and may be involved in the pathophysiology of cancer, from tumorigenesis, proliferation, angiogenesis, and metastasis, to adapting the tumour in its ability to confer upon itself both immune, and chemotherapy resistance (see Yang et al (2014) doi.org / 10.1155 / 2014 / 623759). Overall, targeted, modest or controlled induction of certain cytokines such as interferon-gamma (IFN-g) is considered beneficial whereas the induction of high or uncontrolled levels of cytokine is typically considered detrimental. Consequently AE, CRS and ICANS is a continuing issue and concern with conventional CD3 engagers. Typically, these serious side effects are classified by an agreed harmonized grading system. For example, when measuring CRS and ICANS, a non-limiting example includes MedDRA version 26.0 system (see Lee DW et al. (2019) Apr;25(4):625-638. doi: 10.1016 / j.bbmt.2018.12.758.). Additional concerns associated with this approach relate to the fact that such CD3 engagers mediate the destruction of all antigen-positive cells (on-target, off-disease). This is because "conventional" alphabeta T-cells will kill or are less able to "spare" non-diseased, healthy cells expressing the target antigen once coupled to such cells by conventional CD3 engagers. This can result in significant immune- mediated damage of healthy tissues (e.g. see Harter, M. F et al (2024). Nat. Biomed. Eng 8, 345-360 doi.org / 10.1038 / s41551-023-01156-5).

[0096] Another approach involves designing T-cell engagers comprising a first binding arm which targets the variable domain of a gamma delta T-cell variable domain (such as a gamma nine variable domain) and a second binding arm which targets a target TAA or DAA. It has previously been shown that antigen binding to the variable domain of the gamma delta TCR can trigger receptor activation and may thereby enhance gamma delta T-cell cytotoxicity through selectively enhancing release of granzyme B and perforin. For example, a murine antibody (Clone 7A5) and highly selective only for TCR variable domain gamma-nine (TCR V gamma 9) has been used previously to design bispecific which mediate target cell killing by delta-two, gamma-nine positive T-cells - predominantly blood resident (Oberg et al (2014) doi: 10.1158 / 0008-5472. CAN-13-0675). As such, antibodies which bind the variable domain may operate much like authentic antigens or ligands to trigger receptor activation. Therefore, antivariable domain antibodies which trigger the gamma delta TCR may be considered ligand mimetics. However, whilst targeting the variable domain in this way may result in authentic receptor activation, they will only target a sub-class of gamma delta T-cells. For example, they may target predominantly blood resident cells (e.g. delta-two positive, or gamma 9 positive) or tissue resident T-cells (e.g. delta-one positive cells).

[0097] Finally, and beyond impacting safety and tolerability, significant concerns have also been raised about effector cell induced cytokines providing pro-survival signals to cancers and conferring resistance to effector cell killing. For example, in a clinical trial it was observed that the cytokines induced and associated with CAR-T engineered CD3+ effector T-cells targeting AML actually increased cancer cell resistance to T-cell mediated killing. Furthermore, the resulting cytokine-supported cancers conferred a more exhausted phenotype on effector T-cells. The authors thereby concluded that co-treatment with cytokine signalling inhibitors may be needed, that induced cytokine pro-cancer signals may be a "blind spot" in current approaches, and that "immunotherapy may be undermined by the cytokines induced by these therapies" (Bhagwat et al (2024), DOI: 10.1038 / s41591-024-03271-5). Hence conventional approaches focused on activating a sufficient number of T-cells by conventional means may also generate a fizzing cocktail of cytokines which induce serious AE, exhaust the T-cells, and support cancer cell survival / proliferation. There is a need for more effective bispecific T-cell engagers. A more preferred bispecific engager may be one which engages a sufficient number of a most preferred effector cells found in both blood and in tissue such to mediate and potently kill targeted cancers - whilst not being undermined by excessive cytokine production and / or by immune-mediated damage of healthy tissues.

[0098] There remains a need in the art for new medicaments for cancer immunotherapy that can harness gamma delta T cells maximizing tumour response whilst also limiting toxicity.

[0099] SUMMARY OF THE INVENTION

[0100] The present invention provides immunoconjugates comprising an antibody or antigen-binding fragment thereof comprising a first antibody binding domain that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof; and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof. Such antibody or antigenbinding fragments thereof may suitably be multispecific antibodies, such as bispecific antibodies, that also specifically bind to a second target antigen (different from the first) such as a TAA. The constant domain may be TRDC or a fragment thereof and / or TRGC1 or a fragment thereof and / or TRGC2 or a fragment thereof.

[0101] Throughout this application reference is made to 2+2, 2+1+1, 1+1+1 immunoconjugate formats. The first numeral refers to the number of IL-15 receptor alpha (CD215) domains (each containing a sushi domain) or of IL-15 receptor alpha (CD215)+IL-15 domains (also referred to as sushi-IL-15 domains) are present, the second numeral refers to the number of first antibody binding domains (specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR)) present and the third numeral refers to the number of second binding domains toa second antigen. The differences between these formats are provided in Table 3. To further guide, supporting example designs are also presented in Figure 24 wherein additional building block formats are also referenced as indicated and to further aid understanding.

[0102] TABLE 3:

[0103]

[0104]

[0105] This formatting work builds on the 2+2 immunoconjugate format as described PCT / EP2024 / 053368 since it was found there was enough agonistic "headroom" to dial down activity by replacing one of the first antibody binding domains with a second binding domain which bound a second, different antigen such as a tumour associated antigen (TAA) (a 2+1+1 format). One advantage of this 2+1+1 format is that the resulting IL-15 is delivered to a sub-set of gamma delta cells that are most proximal to the cancer cells expressing the second TAA antigen.

[0106] It was additionally discovered that varying the length, nature and / or presence of the linkers used in led to optimization of the formatting of the complex immunoconjugates, as will be described herein. Further, it was discovered that formats in which the IL-15 cytokine is not covalently bound to the immunoconjugate but instead supplied 'in trans' from a separate expression cassette (and so resulting in I L_15 cytokine being non-covalently bound to the sushi domain) resulted in even more favourable homogeneity profiles and yields during production. This will be described further herein.

[0107] According to a first aspect of the invention, immunoconjugates are provided comprising an antibody or antigen-binding fragment thereof comprising a first antibody binding domain that specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen; and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof does not bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof. Said antibody or antigen-binding fragment thereof may also specifically bind to recombinant antigens comprising one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof.

[0108] In some embodiments, the first antibody binding domain also specifically binds human TRGC1 / TRDC heterodimeric constant domain antigen.

[0109] The antibody or antigen-binding fragment may be a multispecific antibody, optionally a bispecific antibody, and further comprise a second antibody binding domain that specifically binds to a second, different target antigen than the first antibody binding domain. The second antibody binding domain may specifically bind to a tumour associated antigen (TAA), optionally wherein the TAA is EGFR.

[0110] The antibody or antigen-binding fragment thereof may further comprise a human immunoglobulin Fc domain comprising a first chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; and a second chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain. The CH3 domain of the first chain may be engineered to heterodimerise with the CH3 domain of the second chain, optionally wherein the CH3 domain of the first chain comprises the mutations S354C and T366W (EU numbering). The CH3 domain of the second chain may be engineered to heterodimerise with the CH3 domain of the first chain, optionally wherein the CH3 domain of the second chain comprises the mutations Y349C, T366S, L368A, and Y407V (EU numbering). The CH3 domain of the first chain may comprise or consist of the sequence of SEQ ID NO: 425 and / or the CH3 domain of the second chain may comprise or consist of the sequence of SEQ ID NO: 426. The Fc domain may be disabled.

[0111] The IL-15 receptor alpha (CD215) fragment(s) may comprise the IL-15 receptor alpha (CD215) sushi domain, preferably wherein the IL-15 receptor alpha (CD215) sushi domain(s) is a human IL-15 receptor alpha (CD215) sushi domain(s). The at least one IL-15 receptor alpha (CD215) or a functional fragment thereof may be covalently linked to at least one C-terminus of the Fc domain. The at least one IL-15 receptor alpha (CD215) or a functional fragment thereof may be covalently linked to the Fc domain via direct fusion; or the at least one IL-15 receptor alpha (CD215) or a functional fragment thereof may be covalently linked to the Fc domain via a linker (linker 1), optionally wherein the linker (linker 1) is a peptide of about 5 amino acid residues or less in length, optionally wherein the linker comprises or consists of SEQ ID NO: 403.

[0112] The immunoconjugates may further comprise at least one human IL-15 cytokine or a functional fragment thereof covalently linked to the C-terminus of at least one IL-15 receptor alpha (CD215) or functional fragment thereof. In alternate embodiments, the immunoconjugate does not comprise a covalently linked IL-15 cytokine and comprises one or more human IL-15 cytokine(s) or fragment(s) thereof non-covalently bound to one or more IL-15 receptor alpha (CD215) or a functional fragment thereof.

[0113] The one or more IL-15 cytokine(s) or fragment(s) thereof may be IL-15 mutein. The IL-15 mutein(s) or fragment(s) thereof may comprise the sequence of SEQ ID NO: 399 comprising one or more mutations selected from Table 12. The IL-15 mutein(s) or fragment(s) thereof may comprise the sequence of SEQ ID NO: 473.

[0114] The antibody or antigen-binding fragment thereof may be a human antibody or antigen-binding fragment thereof. The antibodies or antigen-binding fragments thereof may specifically bind the constant domain TRDC or a fragment thereof, optionally human TRDC or a fragment thereof.

[0115] The antibodies or antigen-binding fragments thereof may specifically bind the constant domain TRGC1 or a fragment thereof, optionally human TRGC1 or a fragment thereof.

[0116] The antibodies or antigen-binding fragments thereof may specifically bind the constant domain TRGC2 or a fragment thereof, optionally human TRGC2 or a fragment thereof.

[0117] The antibodies or antigen-binding fragments thereof may selectively bind the constant domain TRDC or a fragment thereof and / or TRGC1 or a fragment thereof and / or TRGC2 or a fragment thereof, optionally wherein the constant domain(s) are human.

[0118] The antibodies or antigen-binding fragments thereof may selectively bind the constant domain TRGC1 or a fragment thereof and the constant domain TRGC2 or a fragment thereof, optionally wherein the constant domain(s) are human.

[0119] In some embodiments the second target antigen may be a tumor associated antigen (TAA) such as EGFR, GPC3, CD19, CD20, CD123, CD33, 5T4, EpCAM or CAIX.

[0120] According to one aspect of the invention, there is provided an immunoconjugate comprising an anticonstant gdTCR antibody or antigen-binding fragment thereof as defined by SEQ. ID NO herein, for example those presented in Table 11.

[0121] Also provided herein are methods of using said immunoconjugates, including methods of treating a disease or disorder in a subject, comprising administering to the subject the antibody or antigenbinding fragment thereof provided herein, optionally wherein the disease is cancer or an autoimmune disease.

[0122] Also provided herein is an immunoconjugate, composition or pharmaceutical composition according to the invention for use as a medicament, or for use in the treatment of a disease in a patient, which may be cancer. There is also provided the use of an immunoconjugate according to the invention in the manufacture of a medicament for the treatment of a disease in a patient, which may be cancer. Also provided is an immunoconjugate, composition or pharmaceutical composition according to the invention for use in stimulating the immune system of an individual. Also provided is the use of an immunoconjugate according to the invention in the manufacture of a medicament for stimulating the immune system of an individual.

[0123] Also described herein are recombinant antigens used to identify and develop antibodies of the invention.

[0124] Also provided herein are nucleic acids (polynucleotides) that encode an immunoconjugate or antibody or antigen-binding fragment as described herein. A nucleic acid of the invention may comprise the sequence of SEQ. ID NO: 427, 428 or 429. Also provided are vectors comprising the nucleic acid as described herein. Also provided are host cells comprising the vector as described herein.

[0125] Also provided herein is a method of producing an immunoconjugate or antibody or antigen binding fragment as defined herein, comprising culturing a vector as defined herein or a host cell as defined herein under conditions allowing expression of the immunoconjugate or antibody or fragment and recovering the immunoconjugate or antibody or fragment.

[0126] Also provided herein is the use an antigen as described herein in a method of obtaining an antibody or immunoconjugate. Also provided herein are antibodies obtained or obtainable via a method as described herein.

[0127] In another aspect of the invention there is provided a method of producing an immunoconjugate of the invention, comprising (a) culturing the host cell of the invention under conditions suitable for the expression of the immunoconjugate, and optionally (b) recovering and purifying the immunoconjugate. Immunoconjugates obtained or obtainable by such methods are also provided.

[0128] In one aspect there is provided a method of obtaining antibodies or immunoconjugates that specifically bind to the constant regions of a gdTCR or fragment thereof, the method comprising using at least two of the recombinant antigens as described herein.

[0129] BRIEF DESCRIPTION OF THE DRAWINGS Figure 1: Constant Domain Guidance. (1A) Schematic summary of the gamma delta TCR and areas of notable variation, i = The variable domain (preferably not included in antigen); ii = The "constant" domain - also variable; variation conferred by TRGC gene usage; Exon 2 multiplication; Disulfide linkage; N-linked glycosylation profile (up to 20Kd); Final size / charge; iii =TRGC exon 2 encoded domain of various sizes due to insert multiplication; iv = The hyper variable CDR3 V(D)J domain (average length increases with human age). The two greyed boxes indicate the structural domains of particular interest to this invention. The greyed boxes each comprise (canonical) beta-stranded IgG-like sub-unit of the gamma and delta constant domain respectively. These isolated sub-units are C-terminal of the hypervariable VDJ region and continue through to less structured regions. These greyed areas are of particular interest for inclusion into antigens as described herein.

[0130] (IB) Example Full Length Human Protein Sequence for TRDC, TRGC1 and TRGC2 proteins domains. Example human, cynomolgus and murine protein sequence shown for: Human TRDC sequence (B7Z8K6 TRDC_HUMAN uniprot.org also termed IMGT.org allele TRDC*01); Human TRGC1 sequence (P0CF51 TRGC1_HUMAN uniport.org also termed IMGT allele TRGC1*01); Human TRGC2 sequence (P03986 TRGC2_HUMAN uniport.org also termed IMGT allele TRGC2*06); Human TRGC2 sequence (alternate allele, GenBank: AAB63312.1); Cynomolgus TRDC (A0A7N9CA91_MACFA uniport.org); Cynomolgus TRGC (G7P2C2_MACFA uniport.org); murine TRDC (AOAOG2JEU3_MOUSE) uniprot.org; murine TRGC1 (A0A075B5Z0_MOUSE); murine TRGC2 (A0A075B5Z2_MOUSE)

[0131] Figure 2: Cartoon adaption of a crystal structure of an example TCR of the "GC1" gamma delta TCR class. Cartoon of 1HXM gamma delta TCR crystal structure. This an example of a delta two, gamma nine TCR inclusive of constant domain and variable domain. Note cartoon does not depict a full length TCR as the components of regions encoded by TRDC and TRGC (C-terminal unstructured or connecting region, the transmembrane domain, and cytoplasmic tail / stump) are not incorporated. Such TCRs are typically expressed on gamma delta cells predominant in blood and conventionally termed "delta two" TCRs. By the classification system as now proposed herein, this TCR is an example of a "GC1" class of TCR because the constant domain employed is the TRDC / TRGC1 variant. Location of the canonical beta strands found in the Ig-like constant TRGC1 and TRDC domains are indicated by brackets. Cartoon sourced from https: / / www.rcsb.org / 3d-view / 1HXM.

[0132] Figure 3:-TRGC and TRDC domain structure and sequence including example antigen numbering scheme and key residues (3A) TRGC and TRDC domains in isolation and inclusive of unstructured regions, alpha helical transmembrane regions, and cytoplasmic tail / stumps. Cartoon structure prediction of (i) TRDC, (ii) TRGC1 and (iii) TRGC2 domains in isolation and inclusive of the beta strands of the Ig-like domain (boxed), unstructured connecting regions, helical transmembrane domain and cytoplasmic stump. No N-terminal variable domains are shown. Cartoons adapted from AlphaFold (alphafold.com) - for TRDC see AlphaFold AF-B7Z8K6-F1; for TRGC1 see AF-P0CF51-F1; for TRGC2 see AF-P03986-F1. Cartoons adapted from screenshots and for illustrative purposes only (and not necessarily to the same scale) (3B)TRDC domain structure. The full length TRDC sequence (SEQ ID NO: 1) is shown (amino acids 1-153) alongside an associated AlphaFold model (see also 3A). Highlighted (bold) is the area of particular interest when designing antigens as described herein (Ser1 to Cys110). Contained within this region is the B-strand structured sequence between and inclusive of residues Ser8 and His81. Beta strands (predicted by Uniprot KB) at position 8-14, 17-24, 26-28, 31-35, 37-42, 46-49, 53-63, 70-75 and 78-81 are underlined.-(3C) TRGC1 domain structure. The full length TRGC1 sequence (SEQ ID NO:2) is shown (amino acids 1-173) alongside an associated AlphaFold model (see also 3A). Highlighted (bold) is the area of particular interest when designing antigens as described herein (Asp5 to Cys121). Contained withing this region is the B-strand structured sequence between and inclusive of residues Lys11 through to Phe105. Beta strands (predicted by Uniprot KB) at positions 11-15, 19-25, 26-40, 43-48, 49-51,63-65,68-78, 79-81, 82-84, 86-91, 101-105 are underlined. (3D) TRGC2 domain structure. The full length TRGC2 sequence (SEQ ID NO: 3) is shown (amino acids Aspl to Serl90) alongside an associated AlphaFold model (see also 3A). Highlighted (bold) is the area of particular interest when designing antigens as described herein (Asp5 to Phel05). Contained withing this region is the B-strand structured sequence between and inclusive of residues Lys11 through to Phe105. Beta strands (predicted by UniProtKB, plus an additional as modelled by alphafold for 11-15) at positions 11-15, 24-26, 28-39, 42-51, 66-77,89-92, and 101-105 are underlined. Further detail of TRDC, TRGC1 and TRGC2 domain structure / sequence respectively. (3E) The beta strand intervening loops of TRDC1, TRGC1 and TRGC2 (bold, underlined).

[0133] Figure 4: Protein sequence alignment of human TRDC and TRGC domains. Alignment of different TRGC1 and TRGC2 constant domain sequences (BLOSUM 62 scoring matrix). Consensus sequence shaded. Two variant TRGC2 alleles are shown to highlight single or double inserts for one example alternative TRGC2 allele. Only a TRGC1 single insert and TRGC2 double insert allele examples are shown herein. However reportedly additional multiplications have been observed in certain other TRGC2 variants (see Buresi et al., 1989;29(3):161-72. doi: 10.1007 / BF00373641. Position of the Cys of TRDG1 which pairs with cys contained in the TRDC domain is indicated by box. Also highlighted in the same box is the TRGC2 trp at this position - no interchain cysteine is unique amongst all human TCR constant domains. Figure 5: Example antigen sequence inclusive of an example downstream junction (5A) Schematic cartoon of an example heterodimeric (left) and homodimeric (middle and right) antigens. Optionally, heterodimerisation can be encouraged with aid of knob-in-hole Fc domains. (5B) Example heterodimeric sequence guide. Example junction shown between antigen and associated purification / dimerization domain. In this example, the underlined sequence comprises IgG-like domain of theTRDCand TRGC1 constant domains incorporated into the antigen. Note the dual identity of cysteine at the junction of the gamma delta constant domain and the Ig Fc domain. This Cys can be numbered either as the first cysteine of the Fc sequence (220 / 233; Eu or Kabat numbering respectively) or equally as cysteine 110 of TRDC (SEQ ID NO:1) and cysteine 121 (SEQ ID NO:2) of TRGC1 respectively. When present these cysteines can form an interchain disulfide bridge in antigens as provided herein. Full length IGHG1 sequence not shown.

[0134] Figure 6: Example library of TRGC1 / TRDC heterodimeric human (SEQ ID No: 33 & 34), cyno (SEQ ID No: 35 & 36) and murine (SEQ ID No: 37 & 38) antigens. Note for each antigen sub-unit, a cleavable leader (SEQ ID No: 21) can be included at the N-terminus to encourage secretion in mammalian cells such as CHO and HEK293. Also note each sub-unit contains a C-terminal knob or hole Fc domain (SEQ 24 or 25 respectively) to encourage heterodimerization.

[0135] Figure 7: Example library of TRGC2 / TRDC heterodimeric human antigens. The first antigen (SEQ ID No: 39 & 34) comprises human TRGC2 and TRDC authentic or wild-type sequence and as such no interchain disulfide bond can form between TRGC2 and TRDC chains - the TRDC Cys110 cannot form a disulfide bridge with TRGC2 partner chain which naturally lack a cysteine at the orthologous position. Hence in this antigen, the TRDC Cys110 is present but principally unpartnered. The second antigen (SEQ ID No:40 & 34) comprises TRGC2 sequence with a Trpl37Cys change such to allow the TRGC2 chain to form a disulfide bond between TRGC2 137Cys and TRDC Cys110. The third antigen (SEQ ID No: 39 & 41) comprises wild-type TRGC2 sequence (Trpl37, no cysteine) and TRDC sequence with Cys110Ser modification such to ensure there is no unpartnered Cys in the TRDC sub-unit. Note for each antigen sub-unit, a cleavable leader (SEQ ID No: 21) can be included at the N-terminus to encourage secretion in mammalian cells such as CHO and HEK293. Also note each sub-unit contains a C-terminal knob or hole Fc domain (in this example SEQ 24 or 25 respectively) to encourage heterodimerization.

[0136] Figure 8: Example library of TRDC, TRGC1 and TRGC2 homodimeric human antigens. Note these are homodimers antigens comprising two identical sub-unit with wild-type Fc fusion domains at their C- termini. Also note for each antigen sub-unit, a cleavable leader (SEQ ID No: 21) can be included at the N-terminus to encourage secretion in mammalian cells such as CHO and HEK293.

[0137] Figure 9: Example library of human heterodimeric antigens comprising both constant domain sequence AND variable domain sequence of Figure 9. For Antigen CytAntlO (SEQ ID No:45 and 46), the 1HXM variable domain (and CDR3) sequences are employed. For Antigen CytAntll (SEQ ID No:47 and 48), the 6G7D variable (and CDR3) sequences are employed. For Antigen CytAntl2 (SEQ ID No:49 and 50), the 7LLI variable (and CDR3) sequences are employed. Note for each antigen sub-unit, a cleavable leader (SEQ ID No: 21) can be included at the N-terminus to encourage secretion in mammalian cells such as CHO and HEK293. Also note each sub-unit contains a C-terminal knob or hole Fc domain (SEQ 24 or 25 respectively) to encourage heterodimerization.

[0138] Figure 10: Reduced and Non-reduced analysis of antigens described herein. Example non-reduced and reduced (suffixed as 'r' ) SDS-PAGE analysis of purified gamma delta constant domain antigens against M Protein Standard Marker (Bio-Rad Laboratories Ltd, Hertfordshire UK. A) Example analysis of purified heterodimeric antigens; Lane order: 1= CytAntOl, 2 = CytAntO2, 3= CytAntO3, 4 = CytAntO4, 5 = CytAntO5,6 = CytAntO6, 10 = CytAntlO, 11 = CytAntll, 12 = CytAntl2 B) Example analysis purified homodimeric antigens Lane Order 7 = CytAnt7, 8 = CytAnt8, 9= CytAnt9.

[0139] Figure 11: Example stepwise library screening cascade using the TRDC / TRGC antigens. Initial antibody library sequences can be derived from either a naive or immunized source to generate the initial repertoire of antibodies (or fragments thereof such as scFV and Fab based sequences). Screening can be undertaken in parallel or in series as shown here. For further detail of strategies employed herein (A, B, C and D) – see Figure 12.

[0140] Figure 12: A summary of four different antigen / library discovery strategies. The strategies presented herein used human scFV phage display libraries N05, N06, S01, S02 to discover the human anti-TRDC and anti-TRGC antibodies provided herein. Strategy A, B, C and D are presented in Figure 12 A, B, C and D respectively. See Figures 5, 6, 7, 8 and 9 for further information on the antigens described herein. (A):

[0141] Focus on anti-TRDC selective antibodies. (B): Focus on TRGC1 and TRGC2 selective antibodies. (C):

[0142] Focus on TRGC1 and TRGC2 selective antibodies (alternate approach to (B)). (D): Focus on TRGC2 selective antibodies. Figure 13: A summary of master-plated scFV phage outputs in the "primary screen" ELISA assays against the antigens as indicated. Also indicated is the library and screening strategy employed to generate said outputs.

[0143] Figure 14: A summary of the cross-reactivity of the 29 clones in the second screen ELISA assays against the antigens as indicated. (A): Results presented for 29 clones in a tabulated form. Also indicated is the library and screening strategy employed to generate said clones. For these secondaryscreen ELISA assays, the antigens were either plate-captured as biotinylated antigen (prefixed "Bio-") with neutravidin or not biotinylated and plate-captured. The ELISA values are recorded and also grey-scaled heat maps created. Of note only clone 697 exhibited significant signal to background human IgG (last column). (B) Results for a subset of example clones exhibiting different target antigen selectivity profiles presented in bar chart format. Examples include an antibody specific for TRGC2 containing antigens, an antibody which is specific for TRGC1 containing antigens, and an antibody cross reactive to both antigens - antibodies 1, 2 and 3 respectively.

[0144] Figure 15: Example analysis of fresh blood (PBMC purified) highlighting the relative abundance of the three different subsets of gamma delta cells. The top three plots indicate a standard step-wise flow gating method from left to right comprising gating on forward / side scatter (to avoid debris) then singlets, then live cells. The lower three plots show subsequent analysis on CD3xVDl, CD3xVD2 and CD3xVD3. For this donor (arbitrarily selected) the delta two gamma delta cell content (middle lower plot) is clearly visible at approximately 2% of total CD3 positive immune cells, whilst the lower left plot (delta one) and the lower right plot (delta three) are less visible (both at less than 1% total CD3 positive cells). This aligns with the consensus view which often terms delta-two positive cells as 'blood resident' whilst delta-one and delta-three cells as more tissue-resident.

[0145] Figure 16: Example use of an antibody which selectively binds gamma delta one, delta two and delta three positive cells to increase the relative numbers of all three populations in blood PBMCs.

[0146] Tabulated results on day zero (left hand table pre-incubation with antibody) and day 16 (right hand table) are shown. Significant increases as a proportion of total CD3+ cells is recorded. Plots below tables provide a visual guidance of the delta one (VD1), delta two (VD2) and delta three (VD3) gating strategy and results. This gating was preceded by stepwise, forward / side, then singlet, then live, then CD3+ gating (also see Figure 15 for this pre-gating). Figure 17: Antibody which selectively binds gamma delta one, delta two and delta three positive cells induced down-regulation of gamma delta TCR with antibodies. All three sub-classes (delta one, delta two and delta TCR positive gamma delta cells) exhibited a titratable TCR downregulation upon engagement with the two different antibody clones which recognize and bind all three sub-types.

[0147] Figure 18: Summary of antibody sequences inclusive of Clone ID, domain, chain, and SEQ ID categorization

[0148] Figure 19: Cancer cell killing. Primary human PBMCs enriched for gamma delta cells were mixed with a human cancer cell line. Antibody clones were then titrated into the mix. OKT3 (anti-CD3) was used as a positive control. X / Y axis plots shown report antibody concentration versus antibody induced cell killing (as measured by increased bioluminescence). Absolute values shown on left-hand graph, relative values versus base-line shown on right-hand graph.

[0149] Figure 20: Schematic cartoon summary of Example antibody-mediated cell killing mechanisms. (A) Antibody dependant cell cytotoxicity (ADCC) mediated killing by gamma delta effector T cells. Antibody binds one or more targets expressed on the target cell or cells via Fab domains. The antibody also engages the FcR of the effector gamma delta T cell via Fc domains. FcR is triggered on the gammadelta effector cell. The effector cell then kills the target cell via the immunological synapse or bridge formed by the antibody between the effector cell and target cell. (B) Antibody induced effector cell death (AICD). Antibody binds a selective target such as the gamma delta TCR constant domain via Fab domains. Upon binding, the activation of the TCR induces apoptosis of the effector gamma delta T cell. This killing may be further augmented by cross-linking or ADCC mediated fratricide by neighbouring effector cells (not shown for simplicity). This approach may be of use if one wants to target and kill gamma delta (y6) T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) cells (C) Non-ADCC killing by the gamma delta effector T-cell. Antibody is bound via Fc domain to a target cell which expresses FcR. Antibody is then presented and selectively binds to a target on the effector cell (gamma delta T cell) via its Fab domain. In this instance the Fab target is the constant domain of a gamma delta T-cell receptor. Upon antibody engagement the gamma delta T cell is activated and then kills the target cell presenting the antibody. In this mechanism the FcR is not triggered on the gamma delta T cell, instead both activation and immune synapse formation is mediated by Fab domain engagement of the gamma delta TCR constant domain. Figure 21: Leveraging non-ADCC mediated mechanisms using bispecific antibody formats. (A) Non-ADCC mediated killing; the starting point. This is a replicate of Figure 20(C). It is repeated here to reiterate that this mechanism requires no effector-cell (gamma delta T cell) FcR engagement by the antibody to mediate target cell lysis (B) Non-ADCC target cell lysis with a bispecific antibody. A bispecific format can be designed whereby an anti-constant domain antibody is joined to an antibody targeting an antigen on a target cell (such as a tumor associated antigen). Optionally and given no FcR engagement is needed, the resulting bispecific antibody can be designed with a deleted, disabled or attenuated Fc domain with reduced or no FcR binding capabilities.

[0150] Figure 22: Bispecific antibody examples. (A) Schematic cartoons of Bispecific 1 and Bispecific 2 as described in Example 15, not to scale. Bispecific Antibody 1 comprises a human anti-gamma delta TCR constant domain antibody as provided herein in a scFV format. This is linked to an anti-TAA (target 1) molecule also in a scFV format. Bispecific Antibody 2 comprises a full-length antibody containing 1 Vh / VI Fab binding domain which binds the gamma delta TCR constant domain and 1 Vh / VI Fab domain which binds a TAA (target 2). The IgG Fc domain contains 'LAGA' mutations to reduce FcR binding. (B) Mechanistic cartoon representation of non-ADCC mediated killing of Target 1 positive target cells using Bispecific Antibody 1 (C) Mechanistic cartoon representation of non-ADCC mediated killing of Target 2 positive target cells using Bispecific Antibody 2.

[0151] Figure 23: Anti-gamma delta constant domain x anti-TAA (GPC3) bispecific engagers; binding profile and conferred cytotoxicity effects on TAA-positive cancer cells. For all X / Y plots the bispecific molecule is represented by black circles and starting control anti-gamma delta constant domain antibody and anti-GPC3 antibody are represented by black triangles and black diamonds respectively (A) Schematic cartoon of the example bispecific molecule. The differing binding domains are shown as indicated (B) Binding profile on gamma delta enriched PBMCs. An X / Y plot summary showing % binding of test article to target cells vs. test article / concentration as indicated. (C) Binding profile on TAA positive (GPC3) cancer cells. An X / Y plot summary showing % binding of test article to target cells vs. test article / concentration as indicated (D) Bispecific engager mediated killing of TAA (GPC3) positive cancer cells by gamma delta cells. An X / Y plot summary of a cytotoxicity assay comprising mixed coculture of gamma delta cells and GPC3 positive cancer cells. Cancer cell death vs. test article / concentration as indicated.

[0152] Figure 24: Schematic of Exemplar formats. (A) Example formats all containing 2 copies or 1 copy of an IL-15 polypeptide comprising a sushi-domain covalently joined by a linker to an IL-15 domain and prefixed as "2+" or "1+" accordingly. From left to right, the 2+2 variant contains 2 copies of an antigamma delta constant Fab binding domain (i.e. two copies of the 'anti-constant); the 2+1+1 variant contains one copy of the anti-constant and one copy of a second binding domain such as an anti-TAA binding domain (i.e 'anti-TAA'); the 1+1+1 variant contains one copy each of sushi-l L15, anti-constant, and anti- TAA domains. Additional presented are the modular building blocks: First the "2+ [ ] + [ ]" and the "1+ [ ] + [ ]" complexes as indicated contain one or two copies of the sushi-IL15 domain (with 2x Fabs to be added at the N-terminus). Second the "2+1+ [ ]" and "1+1 [ ]" complexes as indicated contain one or two copies of the sushi-IL15 domain, one copy of the anti-constant, with one anti-TAA Vh / VI domain to be added where indicated. (B) Example formats all containing 2 copies or 1 copy of a C -terminus sushi-domain (without an IL-15 cytokine) and prefixed as "2+" or "1+" accordingly. From left to right, the 2+2 variant contains 2 copies of an anti-constant binding domain; the 2+1+1 variant contains one copy of the anti-constant binding domain and one copy of a second binding domain such as an anti-TAA binding domain. The IL-15 cytokine is then co-expressed 'in-trans' and binds the sushi domain without a linker. Additional presented are the modular building blocks: First the "2+ [ ] + [ ]" and the "1+ [ ] + [ ]" complexes as indicated contain one or two copies of the C-terminus sushi domain (with 2x Fabs to be added at the N-terminus). Second, the "2+1+ [ ]" and "1+1 [ ]" complexes as indicated contain one or two copies of the C-terminus sushi domain, one copy of the anti-constant domain, with one anti-TAA Vh / VI domain to be added where indicated (C) Four and Six polypeptide 2+2 formats. Left-hand highlights a 2+2 format comprising 2 x sushi-IL15 domains and 2 x anti-constant domains comprising 4 polypeptides. Right-hand highlights 2+2 format comprising 2 x sushi-IL15 domains and 2 x anti-constant comprising 6 polypeptides wherein the IL-15 cytokine (polypeptide 5 and 6) is supplied in trans (i.e. from a separate expression cassette) (D) Four and Six polypeptide 2+1+1 formats. Also indicated are charge complimentarily knob-hole CH3 pairs to favour correct polypeptides 1+3 heterodimerisation alongside light chain A / A' and B / B' CH1 / CL pairings to favour correct anticonstant Vh / VI (polypeptide 1 and 2) and anti-TAA Vh / VI (polypeptide 3+4) pairings respectively. Lefthand highlights a 2+1+1 format comprising 2 x sushi-IL15 domains, 1 x anti-constant and 1 x anti-TAA comprising 4 polypeptides. Right-hand highlights a 2+1+1 format comprising 2 x sushi-IL15 domains, 1 x anti-constant and 1 x anti-TAA comprising 6 polypeptides wherein the IL-15 cytokine (polypeptide 5 and 6) is supplied in trans (ie. from a separate expression cassette).

[0153] Figure 25: Optimal IL-15 immunoconjugates (A) Example immunoconjugates variants with differing linker 2 lengths. Linker 2 sequence separating the sushi domain from the C-terminal IL-15 cytokine domain is highlighted; both 'typical' and 'extended' linker 2 example sequence variants presented. (B) Example analytical SEC profiles of variant molecules. Protein A purified material analysed by analytical SEC. Reduced heterogeneity is observed for the extended linker 2 variant (right hand trace) (C) Analytical SEC-MALS example summary results. Results highlight that less higher order structures (e.g. aggregate) are observed for extended linker 2 variant molecules, (D) Longer Linker 2 variants; summary guidance on positioning and length. Linkers of >30 amino acids or of about >30 amino acids are most preferred.

[0154] Figure 26: Alternative IL-15 immunoconjugates (A) Schematic cartoon outlining an 'in-trans' formatted molecule and associated improved profile. A cartoon schematic of the alternate 'in-trans' formatted molecule (top right) is provided. Also shown is the mirrored 'linkered' molecule (top left). The corresponding protein-A eluate profiles are also provided for these molecules (the respective lower traces) (B) Summary of further studies with paired bispecific immunoconjugate. Summary data for nine paired bispecific immunoconjugate molecules are shown. Each pair comprised the exact same N-terminal binding domains in an IgG format but comprised either a C-terminal linkered or in trans supplied IL-15 molecule. Results demonstrate that on all occasions the 'in-trans' format generated improved yields and protein-A eluate monomer content. The first pair (far left,) are the highlighted (boxed) as the same example as described in (A).

[0155] Figure 27. Example in trans immunoconjugates and methods to make them - Summary (A) Summary of C-terminus sushi variants; Sushi domain positioned at C-terminus of heavy chain, IL-15 cytokines supplied 'in trans' and encoded by a separate ORF from a separate expression cassette (B) Example three ORF / expression cassette approach to generate sushi-C-terminus immunoconjugates; top DNA sequence encodes kappa constant light chain - DNA encoding a N-terminal leader sequence and light chain variable domain of interest can be inserted in-frame upstream (5') of this DNA to create an ORF encoding full length antibody light chain. This ORF can be placed into a first expression cassette. Middle DNA sequence encodes a human IgGl CH3 domain fused to a sushi domain at the C-terminus. DNA encoding an N-terminal leader sequence and heavy chain variable domain of interest (and std CHI, hinge, CH2 sequence) can be inserted in-frame upstream (5') of this sequence to create a ORF encoding an antibody heavy-chain with a C-terminus sushi domain. This ORF can be inserted into a second expression cassette. Lower DNA sequence encodes a full-length IL-15. The sequence is combined with DNA encoding an N-terminal leader sequence. This ORF can be inserted into a third expression cassette (C) Real example of three expression cassette approach to generate a immunoconjugate of the invention as described herein containing a C-terminus sushi-domain and an IL-15 cytokine supplied in trans. Step 1; co-transfect the three expression cassettes containing the three ORFs encoding the three polypeptides as indicated into a cell or cells. Step 2; ORFs are translated in the cell into polypeptide component parts; these are then secreted to form the desired complex. Step 3; this complex is then purified (optionally by Protein A chromatography) to generate the final symmetrical immunoconjugate (D) An alternate to (C) wherein two heavy chain expression cassettes both encoding sushi domains at their C-terminus are employed with CH3 variant paired knob or hole CH3 mutations. In this instance the resulting purified immunoconjugate antibody generated contains asymmetry due to the differing but complimentary CH3 domains employed to generate the heavy chain KiH heterodimer containing sushi domains at the C-terminus (E) A variant of (D) wherein only one of the two paired KiH heavy chain ORFs encodes a sushi- domain at the C-terminus. The resulting asymmetrical molecule generated now only contains a single sushi-domain resulting in 1+2 format (1 sushi-Il15 domain, 2 antibody binding domains).

[0156] Figure 28: Optimal IL-15 mutein immunoconjugates (A) Schematic cartoon of an example linkered or in-trans immunoconjugate molecule. Control molecules are shown on the left hand of this schematic. Anti-constant domain immunoconjugates with C-terminal IL-15 components are shown on the right. Molecule identifiers are also listed. The mutations introduced into the IL-15 cytokine are indicated. (B) Relative expression yields / SEC profiles (pre- and post polishing) of immunoconjugates. Top lefthand bar chart highlights the improved profiles of in-trans format after one-step purification. Top-right bar chart highlights that with additional polishing steps, both linkered and in-trans formats generate favourable profiles. Further details (including expression yields) are summarised in the lower Table. (C) Example cell-based IL-15 functionality profiles of immunoconjugates. An X / Y plot summary of cellbased activity vs concentration of test articles as indicated.

[0157] Figure 29: Variant IL-15 mutein immunoconjugates (A) Expression and purification profiles: Results summarized in a tabulated format. All molecules generated in the 'linkered' format as depicted by the cartoon schematic (B) Affinity of anti-constant domain 11-15 immunoconjugates to CD122. Results summarized in a tabulated format. NA = indicates results Not Available; assay undertaken however no result recorded (likely because the affinity of the mutein is below limit of detection / quantification of the SPR assay) (C) Functionality of variant immunoconjugates in a cell based Mo7e proliferation assay: X / Y plot presentations of proliferation activity versus molecule concentration - all data normalized to control (Mo7e cells only). To aid with data visualisation the results have been stratified as follows C (i) focus on mutations in IL-15 at position D30, E64, and N65; C (ii) focus on mutations in IL-15 at position S7 and Q108 C (iii) focus on mutations in IL-15 at position V31, D61, and E64. Figure 30: Variant IL-15 bispecific immunoconjugates (A) Schematic cartoon outlining the design of these bispecific immunoconjugates: Results summarized in a tabulated format. All molecules generated in the 'linkered' format as depicted by the cartoon schematic (B) The targeting concept; a schematic example of the tumour microenvironment "TME" zone (greyed) targeted by the bispecific immunoconjugate - a zone where cells positive for all 3 targets (gamma delta constant domains, CD122, TAA of choice) are proximal resulting in optimal agonistic effects by the immunoconjugate as described herein.

[0158] Figure 31: Anti gamma-delta TCR constant domain antibody binding to gamma delta T-cells. X / Y plots of anti-constant domain antibody % binding to gated population vs titrated antibody concentration. Binding profile to alpha-beta negative gated, gamma delta enriched PBMCs (top plot, boxed). Binding profile to delta-one gated population (bottom left plot). Binding profile to delta-two gated populations (bottom middle plot). Binding profile to delta-three gated populations (bottom right plot).

[0159] Figure 32: Anti gamma-delta TCR constant domain antibody induction of delta T-cells proliferation.

[0160] Bar chart summary of fold-change in gamma delta T-cell number overtime (mean; 2 donors) for exemplar anti-constant domain antibodies (labelled as CYT Abl and CYT Ab2) versus sub-type specific Comparators as indicated. Fold change in delta-one positive gamma delta T-cells (left hand bar chart), in delta-two positive cells (middle bar chart), in delta-three positive cells (right bar chart).

[0161] Figure 33: Anti gamma-delta TCR constant domain antibody induction of delta T-cells degranulation.

[0162] X / Y plot measuring gamma delta T-cell CD107a levels vs titrated antibody concentration for two exemplar anti-constant IgGl antibodies (CYT Abl or CYT Ab2) as described herein or non-binding negative control IgGl (as indicated). Analysis of delta-one gate (left hand plot), delta-two gate (middle plot) ad delta-three gate (right hand plot).

[0163] Figure 34: Anti gamma-delta TCR constant domain antibody induced gamma delta T-cell killing of tumour cells. (A) Composition of gamma delta enriched PBMCs used in the co-incubation cytotoxicity study (B) X / Y plots of the results of the gamma delta cell / cancer cell co-incubation; % live tumour cells vs titrated antibody test article (as indicated) after co-incubation. Left-hand plot highlights anticonstant domain antibody mediated effects for two exemplar antibodies as described and discovered herein (CYT Abl and CYT Ab2) versus a non-binding control IgGl. Right-hand plot compares the relative potency of these anti-constant domain antibodies to comparator sub-set specific antibodies as indicated. Figure 35: Conferred effects of anti-gamma delta constant domain bispecific EGFR engagers on gamma delta enriched PBMCs co-incubated with EGFR positive tumours (A) X / Y plots summarising the levels of cell surface levels of CD107Aa on gated cell populations vs various titrated test articles (as indicated) (B) Bar chart summaries of induced Ki67 marker levels on gated populations vs various titrated test articles (as indicated) (C) X / Y plot summarising the measured levels of tumour cell killing vs various titrated test articles (as indicated) (D) X / Y plot summarising the measured levels of tumour cell killing vs various titrated test articles (as indicated) as a simplified replicate of the data presented in Figure 35 (C) but with additional emphasis added for further guidance. (E) X / Y plots depicting the fold increase in adenylate kinase as a measure of tumour cell lysis. EGFR+ tumour cells (A375) were co-cultured in a 1:1 E:T ratio with enriched γδ T cells from PBMCs (62% γδ T, 27% αβT cells) for 24 hours in the presence of an anti-constant domain x anti-EGFR gamma delta engager (Cyt Engager B) or an anti-CD3 x anti-EGFR 'conventional' engager comparator as indicated. Supernatants were collected and the level of adenylate kinase quantified. Left-hand plot shows increased titratable TAA targeted cancer cell killing is mediated by both the anti-constant domain engager and the conventional CD3 engager. Right-hand plot shows remarkably more controlled / reduced levels of cytokine induction when employing the anti-constant domain engager vs the conventional CD3 engager. (F) X / Y plots depicting the fold increase in adenylate kinase as a measure of TAA targeted killing of diseased or healthy cell with titrated test articles (CYT B Engager or NT Engager as indicated). Left-hand plot demonstrates anti-constant domain dependant, TAA mediated killing of tumour cells by the enriched PBMCs when CYT B Engager is employed. Right-hand plot shows a very little such mediated killing is observed when cancer cells are replaced with a variety of healthy cells - even when very high levels of target TAA (EGFR) are present on such healthy cells.

[0164] Figure 36: Targeting CD19 or CD20 positive diseased cells (A) Analytical flow profiling of purified effector cell populations employed in this cytotoxicity study. Left-hand plot: starting alpha-beta effector T-cell employed; 95.69% alpha beta +ve as indicated. Right-hand plot: starting gamma-delta effector T-cell population employed; 99% gamma delta +ve as indicated (B) Schematic cartoon and tabulated description of molecules employed in this controlled cytotoxicity study (C) Targeted killing of target / antigen positive diseased cells as indicated; X / Y plot summary of % target cells (Raji) killed vs titrated molecule. Upper half; alpha-beta T-cells employed as the effector cell population, right-hand plot, gamma delta T-cells employed as the effector cell population (D) Killing mechanism; additional characterization. Top half indicates that higher levels of the more pleiotropic granzyme B protease is more heavily associated in alpha-beta T-cell mediated killing. In contrast, bottom half highlights a more targeted, more discrete killing profile is mediated by gamma delta effector T-cells (E) Example CRS-related cytokines induced during cytotoxicity assay: X / Y plots summaries of cytokine quantities measured vs titrated test article. Upper half summarizes the vast levels of cytokines induced when alpha-beta T-cells are employed in the cytotoxicity assay if CD3 engagers are employed. Lower half summarizes the reduced levels of cytokine induced when gamma delta T-cells are employed (F) Interferon gamma (IFN-g) and TNF-alpha (TNF-a) induction: X / Y plots summaries of IFN-g and TNF-a quantities measured vs titrated test article. Upper half summarizes the vast levels induced when alphabeta T-cells are employed in the cytotoxicity assay. Lower half summarizes that more controlled levels (of IFN-g) induced when gamma delta T-cells are instead employed. Note differing X-axis and excessive / uncontrolled IFN-g induction observed in the alpha-beta T-cell / CD3 engager arm only.

[0165] Figure 37: Targeting CD123 or CD33 or 5T4 or EpCAM or CAIX positive diseased cells (A) Schematic cartoon and tabulated description of example anti-gamma delta constant domain, anti-TAA bispecific molecules (i) = For one of the Fab domains, the starting Vh-CHl and VI-CL is swapped to generate a Fab comprising Vh-CL and Vl-CH1 such to ensure correct light chain pairing for each Fab domain during production, (ii) = Attenuated Fc domain to reduce binding to FcR. (iii) Reciprocal KiH mutations to favour Fc domain heterodimerization. (B) Schematic cartoon of targeted killing of diseased cells by gamma delta T-cells mediated by such bispecific molecules. (C) Targeted killing of CD33 target / antigen positive THP-1 cancer cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the CD33 disease-associated target antigen. (D) Targeted killing of CD123 target / antigen positive THP-1 cancer cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the CD123 disease-associated target antigen. (E) Targeted killing of 5T4 target / antigen positive A431 cancer cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the 5T4 disease-associated target antigen. (F) Targeted killing of EpCAM target / antigen positive HCT116 cancer cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the EpCAM disease-associated target antigen. (G) Targeted killing of CAIX target / antigen positive A431 cancer cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the CAIX disease-associated target antigen. (H) Targeted killing of CD123 target / antigen positive THP-1 cancer cells co-incubated with molecules of disclosure, as described in Example 23B. (I) Proliferative effects observed with molecules of the disclosure described in Example 23B.

[0166] Figure 38: Targeted killing of CD19 target / antigen positive diseased Raji cells co-incubated with primary human gamma delta T-cells. X / Y plot showing the titratable increased killing profile conferred by bispecific which selectively bind both the constant domain of a gamma delta T-cell TCR and the CD19 disease-associated target antigen.

[0167] Figure 39: Same assay comparisons with differing anti-constant domain antibodies (A) Binding to PEER cells. Studies highlight that the TRGC1 / TRDC selective A10 anti-constant domain antibody does not bind PEER cells effectively (B) Binding to primary gamma delta T-cells gated on VD1 cells, VD2 cells and VD3. Studies shows that the TRGC2 / TRDC selective A03 anti-constant domain antibody exhibits a significant lower binding signal to VD2 cells whilst the anti-TRGCl / TRDC selective A10 clone exhibits a significantly lower binding profile for VD1 or VD3 cells. Finally, the A09, A12 and A14 clones which can selectively bind TRGC1 / TRDC and TRGC2 / TRDC bind all VD1, VD2 and VD3 subsets similarly (C) Cytotoxicity assays involving gamma delta cells co-incubated with THP-1 cells plus test antibodies as indicated. Lefthand study used gamma delta effector cells more enriched for VD1 cells as indicated in the upper bar chart. The righthand study used gamma delta effector cells similarly enriched for VD1 and VD2 cells, again see upper bar chart. Study shows that the more selective A03 and A10 anticonstant domain antibodies are inferior relative to true-pan binders able to bind all gamma delta cells similarly and that the degree of inferiority may be impacted by the VD1 / VD2 / VD3 ratio of the gamma delta effector cells employed in the assay.

[0168] Figure 40: AlphaFold modelling of antibody / antigen engagement: (A) A static model of the full length TCR / CD3 complex including the position of example loops located on the 'shoulder' TRGC / TRDC complex (B). Modelling approach undertaken to model antibody engagement with isolated Ig-like domains Vh: VI: TRGC: TRDC engagement using AlphaFold (C) Model of isolated TRGC1 / TRDC Ig-like domain including position of BC / FG loop shoulder and more C-terminal G-sheet flanking regions.

[0169] Figure 41: Binding profile comparison of anti-TRGCl / TRDC selective antibodies vs broader anti-TRGC1 / TRGC2 selective antibodies. In each graph, anti-TRGCl / TRGC2 selective antibodies (black and dark grey coloured bars - A09 and A14)) flank the more anti-TRGCl only biased antibody (light grey bars - A10) in the middle (A) Binding to primary gamma delta T-cells (left-hand bar chart) (B) Binding to human gamma delta TRGC2 positive PEER cell line (right-hand bar chart).

[0170] Figure 42: Attempted TRGC1 / TRDC and TRGC2 / TRDC deglycosylation. Attempted native (nondenaturing) deglycosylation of AntOl and Ant04. Top row AntOl; bottom row Ant04. The major peak identified via LC-MS analysis is indicated by circle for each analysis. Left hand columns: LC-MS analysis of starting antigen. Middle column LC-MS analysis of control deglycosylated, denatured antigen: Right column LC-MS analysis of (attempted) deglycosylated, non-denatured antigen - only TRGC1 / TRDC antigen is successfully deglycosylated under more native or non-denaturing conditions thereby further highlighting the differences between TRGC1 / TRDC and TRGC2 / TRDC antigens as provided herein and the importance of considering use of both such antigens in the methods of the invention.

[0171] Figure 43: Comparative binding profile of antibodies against primary (mixed) gamma delta T-cells, or VD1, or VD2, or VD3 sub-gated populations. Bar chart summaries presented. TRGC1 biased clones generated from a prior campaign (CYTA161, CYTA163 and CYTA165) and TRGC1 and TRGC2 'true pan' specific clones (CYTA115 and RIO) identified using antigens provided herein. Bar chart orientation: binding to mixed human gamma delta enriched PBMCs (top, far left), VD1 positive sub-gate (top, second from left VD2), VD2 positive sub-gate (top, far right), VD3 sub-gate (bottom, left), and alphabeta sub-gate (bottom, right). Figure highlights that the TRGCl-biased clones underperform when targeting VD1 and VD3 sub-gates thereby highlighting the preference of VD1 and VD3 cells for use of TRGC2.

[0172] Figure 44: Example discovery campaign output: Lefthand flow diagram represents an example prior campaign employing antigens we believe comprised variable domains (represented by the 1HXM crystal structure). In this campaign, all selected antibodies generated were characterized as either variable domain selective, or likely constant / part variable domain selective, or proven TRGC1 / TRDC-biased by research herein. Righthand flow diagram represents our example campaign which employs antigens not containing variable domain. Via this constant domain centric approach, all selected binders discovered are not selective for the variable domain and a most preferred subset exhibit significantly less TRGC1 or TRGC2 bias. As such this class can be termed true-pan or universal binders given they are characterized as selective for human TRGC1 containing TCRs and human TRGC2 containing TCRs (and cynomolgus TCR). Figure 45: Example of TRGC2 / TRDC selective bias or binding profile: Sequences and alignment highlights the extended Vh CDR3 of A03 inclusive of non-canonical cysteines. Also shown are three daughter molecules (A037, A038 and A039) wherein these non-canonical cysteines are removed by different mutational strategies. Also included in this study is an anti-RSV antibody as a negative control. The X / Y plots below the alignment show titration (X axis) of the A03 antibody or mutated daughter molecules against primary gamma delta cells (mixed 'pan' population) or VD1 or VD2 or VD3 gated subsets as indicated Y axis indicated MFI as measured by flow-based analysis (with aid of a secondary labelling anti-lg antibody). First, these results further highlight the finding that the A03 molecule exhibits a very significant binding bias towards VD1 and VD3 subsets - these subsets typically contain more TRGC2+ve TCRs. Second it demonstrates that all attempts to remove the non-canonical cysteines failed and ablated all binding.

[0173] DETAILED DESCRIPTION OF THE INVENTION

[0174] Before the various embodiments are described, it is to be understood that this disclosure is not limited to the particular embodiments described, and as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present teachings will be limited only by the appended claims.

[0175] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in any way. While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.

[0176] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, some exemplary methods and materials are now described.

[0177] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which can be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present teachings. Any recited method can be carried out in the order of events recited or in any other order which is logically possible. All patents and publications, including all sequences disclosed within such patents and publications, referred to herein are expressly incorporated by reference.

[0178] Definitions

[0179] Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, nucleic acids are written left to right in 5' to 3' orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively.

[0180] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Still, certain terms are defined below for the sake of clarity and ease of reference.

[0181] The singular terms "a," "an," and "the" include plural referents unless context clearly indicates otherwise. It is further noted that the claims can be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only" and the like in connection with the recitation of claim elements, or use of a "negative" limitation.

[0182] The term "about" as used herein includes up to and including 10% greater and up to and including 10% lower than the value specified, suitably up to and including 5% greater and up to and including 5% lower than the value specified, especially the value specified. The term "between", includes the values of the specified boundaries.

[0183] The term "immunoconjugate" as used herein refers to an antibody format (meaning all or part of an antibody) which is joined to a second molecule. The second molecule may be a cytokine and / or cytokine receptor, a radioactive agent, a cytotoxin, an interferon, a target or reporter moiety, an enzyme, a toxin, a peptide or protein, a therapeutic agent or a chemotherapeutic agent. When the second molecule includes a cytokine the immunoconjugate can also be known interchangeably as an "immunocytokine". Other examples of immunoconjugates include antibody drug conjugates and antibody-toxin fusion proteins. The antibody format may be any of those described herein. The term "fragment" as used herein in the context of a peptide or polypeptide, refers to a peptide or polypeptide that comprises less than the full length amino acid sequence. Such a fragment may arise, for example, from a truncation at the amino terminus, a truncation at the carboxy terminus, and / or an internal deletion of a residue(s) from the amino acid sequence. Fragments may, for example, result from alternative RNA splicing or from in vivo protease activity. The term "functional fragment" refers to a peptide or polypeptide that comprises less than the full length amino acid sequence but retains the functional activity of the full length amino acid sequence from which the fragment is derived (for example the binding profile, the KD, or the agonistic properties).

[0184] The term "antigen" as used herein refers to any substance that has antigenic or immunogenic activity in an animal, preferably a mammal, and most preferably in a human, that is capable of evoking an immune response. Antigens may also be referred to as "immunogens".

[0185] The term "covalently linked" as used here (also referred to as "covalently bound", "covalently joined" or "covalently attached" refers to multiple molecules being chemically joined together by a covalent bond which involves the forming of electron pairs between the molecules by sharing of electrons. For example, two peptides that are fused together via a peptide bond are covalently linked.

[0186] The term "non-covalently linked" as used here (also referred to as "non-covalently bound", "non-covalently joined" or "non-covalently attached" refers to multiple molecules being joined together without the sharing of electrons. Non-covalent bonds generally involve electromagnetic interactions between molecules including but not limited to ionic bonds, hydrophobic effects, hydrogen bonding, van der Waals forces, and electrostatic interactions. For example, a ligand and receptor are usually bound together by non-covalent linkage.

[0187] The term "directly fused" as used herein refers to multiple naturally non-contiguous polypeptides being physically or chemically joined together without an intermediate joining moiety, such as an additional linker that is disparately sourced or designed. This includes the molecules being covalently bound or linked together, without a disparate linker. This can refer to fusions created through the joining of two or more genes or gene fragments that originally coded for separate (ie naturally noncontiguous) proteins or peptides into a single open reading frame which is then expressed and translated as a single contiguous polypeptide without an intermediate disparate linker, The term "agonist" as used herein refers to a substance that binds to a target receptor and change the receptor activity to produce a response, e.g. activate the receptor. Agonists therefore have both affinity and intrinsic efficacy. An "agonistic antibody" or "agonistic immunoconjugate" will therefore bind to a receptor and cause the same action as the substance that normally binds to the receptor. An "inverse agonist" is one which binds to a receptor and causes the opposite action as the substance that normally binds to the receptor e.g. reduces receptor activity.

[0188] The term "antagonist" as used herein refers to a substance that binds to a target receptor but does not produce a response, e.g. blocks the receptor but does not activate it. Antagonists therefore have affinity but not intrinsic efficacy. An "antagonistic antibody" or "antagonistic immunoconjugate" will therefore bind to a receptor and by virtue of occupying a fraction of the receptor population, reduces the probability of occupancy by an agonist. Such antibodies or immunoconjugates are therefore referred to as "blocking antibodies" or "blocking immunoconjugates".

[0189] The term "immunostimulant" or "immunostimulators" are substances that promote the activation of immune system components or cells, therefore stimulating the immune system into producing or increasing an immune response. Immunostimulants may be specific, for example an antigen or vaccine, or may be non-specific and operate without antigen specificity, for example an adjuvant. An "immune response" is a measurable change in at least one cell, or one cell-type, or one endocrine pathway, or one exocrine pathway, of the immune system (including but not limited to a cell-mediated response, a humoral response, a cytokine response, a chemokine response), for example upon addition of a modulating immunocytokine.

[0190] The term "immune cell" as used herein, refers to a cell of the immune system including, but not limited to, CD34+ cells, B-Cells, CD45+ (lymphocyte common antigen) cells, Alpha-Beta T-cells, Cytotoxic T-cells, Helper T-cells, Plasma Cells, Neutrophils, Monocytes, Macrophages, Red Blood Cells, Platelets, Dendritic Cells, Phagocytes, Granulocytes, Innate lymphoid cells, Natural Killer (NK) cells and Gamma Delta T-cells. Typically, immune cells are classified with the aid of combinatorial cell surface molecule analysis (e.g., via flow cytometry) to identify or group or cluster to differentiate immune cells into subpopulations.

[0191] The term "subject" or "patient" refers to any animal, including, but not limited to, mammals such as humans. The term "composition" as used herein, is intended to encompass a product containing the specified ingredients (e.g. an immunoconjugate of the invention) in, optionally, the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in, optionally, the specified amounts.

[0192] The term "cancer," as used herein, refers to the abnormal growth or division of cells. Cancers may be benign, pre-malignant or malignant. Generally, the growth and / or life span of a cancer cell exceeds, and is not coordinated with, that of the normal cells and tissues around it. Cancer occurs in a variety of cells and tissues, including the oral cavity (e.g., mouth, tongue, pharynx, etc.), digestive system (e.g., oesophagus, stomach, small intestine, colon, rectum, liver, bile duct, gall bladder, pancreas, etc.), respiratory system (e.g., larynx, lung, bronchus, etc.), bones, joints, skin (e.g., basal cell, squamous cell, meningioma, etc.), breast, genital system, (e.g., uterus, ovary, prostate, testis, etc.), urinary system (e.g., bladder, kidney, ureter, etc.), eye, nervous system (e.g., brain, etc.), endocrine system (e.g., thyroid, etc.), and hematopoietic system (e.g., lymphoma, myeloma, leukaemia, acute lymphocytic leukaemia, chronic lymphocytic leukaemia, acute myeloid leukaemia, chronic myeloid leukaemia, etc.).

[0193] The term "host" as used herein refers to an animal, preferably a mammal, and most preferably a human.

[0194] The term "host cell" or "recombinant host cell" as used herein refers to the particular subject cell transfected with a (recombinant) nucleic acid molecule and the progeny or potential progeny of such a cell. Progeny of such a cell may not be identical to the parent cell transfected with the nucleic acid molecule due to mutations or environmental influences that may occur in succeeding generations or integration of the nucleic acid molecule into the host cell genome. For example, a Chinese hamster ovary (CHO) cell, which is an epithelial cell line derived from the ovary of the Chinese hamster, may be used as a host cell.

[0195] The term "effective amount" refers to an amount of an immunocytokine or composition or pharmaceutical composition containing said immunocytokine that is effective, at dosages and for periods of time necessary, to achieve the desired effect, including a therapeutic or prophylactic result. For example the term could refer to the amount of an immunocytokine of the invention to achieve a specified result (e.g. an agonistic effect). The term "therapeutically effective amount" refers to the minimum concentration of an immunocytokine or composition or pharmaceutical composition containing said immunocytokine required to effect a measurable improvement or prevention of a particular disease or disorder. A therapeutically effective amount herein may vary according to factors such as the disease state, age, sex, and weight of the patient, and the ability of the immunocytokine to elicit a desired response in the individual. A therapeutically effective amount is also one in which toxic or detrimental effects of the antibody are outweighed by the therapeutically beneficial effects.

[0196] The term "affinity" as used herein is a measure of the binding strength between an antigen and an antigen-binding site on the antibody (or antigen-binding fragment thereof). Affinity is represented by the equilibrium constant for the dissociation of an antigen with an antigen-binding polypeptide (KD). The lower the KD value, the stronger the binding strength between an antigen and the antigen-binding site. Alternatively, the affinity can also be expressed as the affinity constant (KA), which is 1 / KD. Any KD value less than 10-6 is considered to indicate binding. Affinity can be determined by known methods, depending on the specific antigen of interest. For example. KD may be determined by surface plasmon resonance. KD may also be determined by Scatchard analysis and / or competitive binding assays, such as radioimmunoassays (RIA), enzyme immunoassays (EIA) and sandwich competition assays, equilibrium dialysis, equilibrium binding, gel filtration, ELISA, or spectroscopy (e.g. using a fluorescence assay) and the different variants thereof known in the art. The binding affinity of the immunoconjugate or fragment thereof may be established by coating the immunoconjugate or fragment thereof directly or indirectly (e.g. by capture with an anti-human IgG Fc) onto a sensor surface (e.g. an amine high capacity chip or equivalent), wherein the target bound by the immunoconjugate or fragment thereof is flowed over the sensor surface to detect binding. Suitably, a MASS-2 instrument (which may also be referred to as Sierra SPR-32) is used at 25ºC in PBS + 0.02 % Tween 20 running buffer at 30 µl / min.

[0197] The term "avidity" as used herein is the measure of the strength of binding between an antibody, or antigen-binding fragment thereof, and the antigen. Avidity is related to both the affinity between an antigen and its antigen-binding site on the antibody and the number of binding sites for that antigen present on the antibody.

[0198] Other terms are defined herein within the description of the various aspects of the invention.

[0199] IMMUNOCONJUGATES OF THE INVENTION Provided herein are immunoconjugates comprising an antibody or antigen-binding fragment thereof comprising a first antibody binding domain that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof; and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof.

[0200] Arrangement and design of immunoconjugates of the invention

[0201] The two components of the immunoconjugates of the invention are the antibody or antigen-binding fragments thereof (which may be a multivalent antibody or antigen-binding fragment thereof) and the IL-15 component (which comprises at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and may optionally further comprise an IL-15 cytokine).

[0202] The antibody or antigen-binding fragment thereof may comprise at least two (preferably exactly two) immunoglobulin heavy chains and at least two (preferably exactly two) immunoglobulin light chains.

[0203] The antibody or antigen-binding fragment thereof comprises at least one antibody binding domain, and may comprise at least two antibody binding domains. The first antibody binding domain specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof (a first target antigen). The second antibody binding domain (if present) specifically binds to a second, different target antigen. Preferably the second target antigen is a TAA. The TAA may be selected from the group consisting of EGFR and GPC3. Preferably, the second antibody binding domain specifically binds to a second target antigen which is EGFR. The second target antigen is not the same as the first target antigen. The first and second antibody binding domains may be on different chains. The first antibody binding domain may comprise one immunoglobulin heavy chain and one immunoglobulin light chain and the second antibody binding domain may comprise one, different, immunoglobulin heavy chain and one, different, immunoglobulin light chain.

[0204] As used herein, the terms "N-terminal" and "C -terminal" with respect to peptides, polypeptides or proteins have their normal meaning in the art. The N-terminus (also known as N-term, aminoterminus, amine terminus or NH2-terminus) refers to the start of a protein or polypeptide chain (the N refers to the free amide group at the start of the chain). The C-terminus (also known as C-term, caboxy-terminus, carboxyl-terminus or COOH-terminus) refers to the end of a protein or polypeptide chain (the C refers to the free carboxylic group at the end of the chain). If one component is referred to as being "N-terminal" to a second component, this means that, within the polypeptide chain, the first component is positioned closer to the N-terminus than the second component is. If one component is referred to as being "C-terminal" to a second component, this means that, within the polypeptide chain, the first component is positioned closer to the C-terminus than the second component is. If one component is referred to as being at the "N-terminus" of a polypeptide chain, this refers to the component being the first component in the chain, since there is only one N-terminus in each polypeptide chain. If one component is referred to as being at the "C-terminus" of a polypeptide chain, this refers to the component being the last component in the chain, since there is only one C-terminus in each polypeptide chain. Translation of a protein from messenger RNA occurs in an N- to C-terminal direction.

[0205] The multivalent antibody or antigen-binding fragment thereof comprises a human immunoglobulin Fc domain or fragment thereof. The Fc domain comprises two chains which may be the same or may be different. The first chain comprises, in an N- to C- terminal direction, a CH2 domain and a CH3 domain. The second chain comprises, in an N- to C- terminal direction a CH2 domain and a CH3 domain. The multivalent antibody or antigen-binding fragment thereof may further comprise a CHl-hinge domain. The first chain may comprise, in an N- to C- terminal direction, a CHI domain, a hinge domain, a CH2 domain and a CH3 domain. The second chain may comprise, in an N- to C- terminal direction a CHI domain, a hinge domain, a CH2 domain and a CH3 domain. The IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the C-terminus of the Fc domain, optionally via a linker. When only one IL-15 receptor alpha (CD215) or a functional fragment thereof is present the IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the C-terminus of the first chain of the Fc domain or the C-terminus of the second chain of the Fc domain, optionally via a linker. When two IL-15 receptor alpha (CD215) or functional fragments thereof are present a first IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the C-terminus of the first chain of the Fc domain optionally via a linker and a second IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the C-terminus of the second chain of the Fc domain optionally via a linker.

[0206] The structure and sequence of the multivalent antibody or antigen-binding fragment thereof is dealt with in more detail below.

[0207] The linker that may join the IL-15 receptor alpha (CD215) or a functional fragment thereof to the multivalent antibody or antigen-binding fragment thereof (specifically the C-terminus of the Fc domain) may be known as "linker 1" and is described elsewhere herein. The two antibody binding domains are N-terminal to the Fc domain and the IL-15 receptor alpha (CD215) or a functional fragment thereof is C-terminal to the Fc domain, such that the antibody binding domains and the IL-15 receptor alpha (CD215) or a functional fragment thereof are separated from each other by the Fc domain.

[0208] In some embodiments, the immunoconjugate does not comprise a covalently linked IL-15 cytokine and the IL-15 receptor alpha (CD215) or a functional fragment thereof is at the C-terminus of the polypeptide chain. In such embodiments, the immunoconjugate may comprise at least one human IL-15 cytokine non-covalently bound (non-covalently associated) to the IL-15 receptor alpha (CD215) or a functional fragment thereof. In such embodiments the IL-15 cytokine and the IL-15 receptor alpha (CD215) or a functional fragment thereof are joined by their receptor-ligand binding properties, in other words the IL-15 cytokine binds to its cognate receptor (the IL-15 receptor alpha (CD215) or a functional fragment thereof). In such embodiments the IL-15 cytokine and the IL-15 receptor alpha (CD215) or a functional fragment thereof do not form part of the same polypeptide chain and the IL-15 cytokine is expressed separately and presented "in trans" to the IL-15 receptor alpha (CD215) or a functional fragment thereof. The immunoconjugate may comprise one human IL-15 cytokine or fragment thereof non-covalently bound to a first IL-15 receptor alpha (CD215) or a functional fragment thereof. The immunoconjugate may comprise a first human IL-15 cytokine or fragment thereof non-covalently bound to a first IL-15 receptor alpha (CD215) or a functional fragment thereof and a second human IL-15 cytokine or fragment thereof non-covalently bound to a second IL-15 receptor alpha (CD215) or a functional fragment thereof.

[0209] In some other embodiments, immunoconjugate further comprises a covalently linked human IL-15 cytokine. The IL-15 receptor alpha (CD215) or a functional fragment thereof and may optionally also comprise an IL-15 cytokine. The human IL-15 cytokine may be covalently linked to the C-terminus of the at least one IL-15 receptor alpha (CD215) or functional fragment thereof. In such embodiments the IL-15 cytokine and the IL-15 receptor alpha (CD215) or a functional fragment thereof form part of the same polypeptide chain. The immunoconjugate may comprise one human IL-15 cytokine or fragment thereof covalently linked to the C-terminus of a first IL-15 receptor alpha (CD215) or a functional fragment thereof. The immunoconjugate may comprise a first human IL-15 cytokine or fragment thereof covalently linked to the C-terminus of a first IL-15 receptor alpha (CD215) or a functional fragment thereof and a second human IL-15 cytokine or fragment thereof covalently linked to the C-terminus of a second IL-15 receptor alpha (CD215) or a functional fragment thereof. The IL-15 cytokine and the IL-15 receptor alpha (CD215) or functional fragment thereof may be directly fused to each other. The IL-15 cytokine and the IL-15 receptor alpha (CD215) or functional fragment thereof may be joined via a linker.

[0210] The linker that may covalently join the N-terminus of the IL-15 cytokine to the C-terminus of IL-15 receptor alpha (CD215) or a functional fragment thereof may be known as "linker 2" and is defined elsewhere herein.

[0211] The two types of component in the immunoconjugates (the IL-15 component and the antibody component) will now be described in more detail. The arrangement and design of immunoconjugates described herein applies to each of the components now described in more detail.

[0212] Antibody (or antigen-binding fragment) portion of the immunoconjugate

[0213] The present invention provides an immunoconjugate comprising an antibody or antigen-binding fragment thereof that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof. In preferred embodiments the antibody is a human antibody.

[0214] In one aspect, the invention provides an immunoconjugate comprising an antibody or antigen-binding fragment thereof that specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen, wherein the antibody or antigen-binding fragment thereof is a human antibody or antigenbinding fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof also specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen.

[0215] The term "antibody" as used herein may be used interchangeably with term "immunoglobulin" or "Ig" and means an immunoglobulin molecule that recognizes and specifically binds to a target, such as a protein, polypeptide, peptide, carbohydrate, polynucleotide, lipid, or combinations of the foregoing through at least one antigen recognition site within the variable region of the immunoglobulin molecule. As used herein, the term "antibody" encompasses intact polyclonal antibodies, intact monoclonal antibodies, antibody fragments (such as Fab, Fab', F(ab')2, and Fv fragments), single chain Fv (scFv) mutants, chimeric antibodies, fully human antibodies, humanized antibodies, fusion proteins comprising an antigen determination portion of an antibody, and any other modified immunoglobulin molecule comprising an antigen recognition site so long as the antibodies exhibit the desired biological activity. The term "antibody" can also refer to a Y-shaped glycoprotein with a molecular weight of approximately 150 kDa that is made up of four polypeptide chains: four polypeptide chains: two heavy (H) chains and two light (L) chains. Each chain is divided into a constant region and a variable domain. The heavy (H) chain variable domains are abbreviated herein as VH, and the light (L) chain variable domains are abbreviated herein as VL. These domains, domains related thereto and domains derived therefrom, may be referred to herein as immunoglobulin chain variable domains. The VH and VL domains (also referred to as VH and VL regions) can be further subdivided into regions, termed "complementarity determining regions" ("CDRs"), interspersed with regions that are more conserved, termed "framework regions" ("FRs"). The framework and complementarity determining regions have been precisely defined (Kabat et al. Sequences of Proteins of Immunological Interest, Fifth Edition U. S. Department of Health and Human Services, (1991) NIH Publication Number 91-3242). There are also alternative numbering conventions for CDR sequences, for example those set out in Chothia et al. (1989) Nature 342: 877-883 or as summarized by IMGT.org. For guidance, antibody CDRs herein are defined by Kabat. However these CDR sequences are non-limiting. An ordinarily skilled person will be able to define CDRs by alternative standard definitions. Open-access freeware such as provided by abysis.org and the like can be routinely employed to aid with such definitions. Typically by alternate definitions, a specific CDR may be the same, or marginally longer or shorter by sequence length. An ordinarily skilled person will readily recognize that regardless of which convention is employed to define a CDR, it is essentially the same CDR. In a conventional antibody, each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The conventional antibody tetramer of two heavy immunoglobulin chains and two light immunoglobulin chains is formed with the heavy and the light immunoglobulin chains inter-connected by e.g. disulphide bonds, and the heavy chains similarly connected. The whole antibody thus comprises two Fabs, each Fab comprising a VH-VL domain pair. The heavy chain constant region includes three domains, CHI, CH2 and CH3. The light chain constant region is comprised of one domain, CL. The variable domain of the heavy chains and the variable domain of the light chains are binding domains that interact with an antigen. The constant regions of the antibodies typically mediate the binding of the antibody to host tissues or factors, including various cells of the immune system (e.g. effector cells) and the first component (Clq) of the classical complement system. This also includes antibodies comprising an Fc region that has been engineered to contain antigen-binding loops in its CH3 domain - this modified Fc region is termed an "Fcab" (Fc with antigen binding). Antibodies may be oligoclonal, polyclonal, monoclonal (including full-length monoclonal antibodies), camelised, chimeric, CDR-grafted, single-domain, catalytic, chimeric, humanized, anti-idiotypic, including antibodies that can be labelled in soluble or bound form as well as fragments, variants or derivatives thereof, either alone or in combination with other amino acid sequences provided by known techniques. An antibody may be from any species. A "human antibody" or "fully human antibody" refers to antibodies derived from human germline immunoglobulin sequences. Human antibodies provoke less cross-species antibody responses when administered to a human subject. The CDR, framework and / or constant region of the antibody or antigen-binding fragment thereof may be derived from a human Ig sequence, in particular a human IgG sequence. Human antibodies may include some amino acid residues not encoded by human germline immunoglobulin sequences (e.g. mutations introduced by random or site-specific mutagenesis or by somatic mutation). However, the term is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. An advantage of using human antibodies is that they are low or non-immunogenic in humans. Human antibodies that are prepared, expressed, created or isolated by recombinant means, such as antibodies expressed using a recombinant expression vector transfected into a host cell, antibodies isolated from a recombinant, combinatorial human antibody library, antibodies isolated from an animal (e.g. a mouse) that is transgenic for human immunoglobulin genes or antibodies prepared, expressed, created or isolated by any other means that involves splicing of human immunoglobulin gene sequences to other DNA sequences, may also be referred to as "recombinant human antibodies".

[0216] Substituting at least one amino acid residue in the framework region of a non-human immunoglobulin variable domain with the corresponding residue from a human variable domain is referred to as "humanisation". Humanisation of a variable domain may reduce immunogenicity in humans.

[0217] Antibodies or antigen-binding fragments thereof can be naked or conjugated to other molecules such as toxins, radioisotopes, etc.

[0218] "EU numbering" refers to a numbering convention used for the numbering of amino acid residues in antibodies. Each residue of the antibody is assigned a number to allow comparison of antibodies. Where a variant antibody contains a residue that was not present in the wildtype antibody (e.g. an insertion mutation) decimals are used to indicate the insertion. For example, if a residue was inserted between the residues designated numbers 1 and 2, the new residue would be given the EU number 1.1. EU numbering is an alternative numbering scheme to others such as Kabat, (Kabat et al. Sequences of Proteins of Immunological Interest, Fifth Edition U. S. Department of Health and Human Services, (1991) NIH Publication Number 91-3242). Chothia (Chothia et al. (1989) Nature 342: 877-883) or as summarized by IMGT.org. wherein EU numbering is presented with further cross reference to Edelman, G. M. et al., Proc. Natl. Acad. USA, 63, 78-85 (1969). (10.1073 / pnas.63.1.78). The term "epitope" as used herein refers to a localised region of the antigen or target which is specifically bound by the antibody or antigen-binding fragment thereof. Epitopes usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and have specific three-dimensional structural characteristics as well as specific charge characteristics. Epitopes found on protein targets may be defined as "linear epitopes" or "conformational epitopes". Linear epitopes are formed by a continuous or semi-continuous sequence of amino acids in a protein antigen. Conformational epitopes are formed of amino acids that are discontinuous in the protein sequence, but which are brought together upon folding of the protein into its three-dimensional structure. Epitopes may also be referred to as "antigenic determinants". An antibody binds "essentially the same epitope" as another antibody when they both recognize and bind identical or sterically overlapping epitopes. Commonly used methods to determine whether two antibodies bind to identical or overlapping epitopes are competition assays, which can be configured in a number of different formats (e.g. well plates using radioactive or enzyme labels, or flow cytometry on antigen-expressing cells) using either labelled antigen or labelled antibody. An antibody binds "the same epitope" as another antibody when they both recognize and bind identical epitopes (i.e. all contact points between the antigen and the antibody are the same). Various techniques are known in the art to establish which epitope is bound by an antibody. Exemplary techniques include, for example, routine cross-blocking assays, antibody "binning", alanine scanning mutational analysis, peptide blot analysis, peptide cleavage analysis crystallographic studies and NMR analysis. In addition, methods such as epitope excision, epitope extraction and chemical modification of antigens can be employed. Another method that can be used to identify the amino acids within a polypeptide with which an antibody interacts is hydrogen / deuterium exchange detected by mass spectrometry. In general terms, the hydrogen / deuterium exchange method involves deuterium-labelling the protein of interest, followed by binding the antibody to the deuterium-labelled protein. Next, the protein / antibody complex is transferred to water and exchangeable protons within amino acids that are protected by the antibody complex undergo deuterium-to-hydrogen back-exchange at a slower rate than exchangeable protons within amino acids that are not part of the interface. As a result, amino acids that form part of the protein / antibody interface may retain deuterium and therefore exhibit relatively higher mass compared to amino acids not included in the interface. After dissociation of the antibody, the target protein is subjected to protease cleavage and mass spectrometry analysis, thereby revealing the deuterium-labelled residues which correspond to the specific amino acids with which the antibody interacts. A "Fab region" as used herein refers to a portion of an antibody (or constructs that contain said portion) comprising a VH-VL domain pair providing an antigen-binding site (also known as a CDR based antigen binding site). The Fab region may further comprise the CL and CHI domains. A conventional antibody with two heavy and two light chains thus comprises two Fabs, each Fab comprising a VH-VL domain pair.

[0219] The term "crossmab" or "CL-CH1 switching" as used herein refers to modifications to multispecific antibodies wherein a heavy chain and light chain have their respective CL and CHI domains or portions thereof switched (replaced with each other) in one binding arm such to encourage correct light-chain / heavy-chain pairing and / or reduce wrong light-chain / heavy-chain pairing (also termed mispairing). Examples of this approach are further described by Schaefer, W. et al., PNAS, 108 (2011) 11187-1191 DOI: 10.1073 / pnas.1019002108

[0220] The term "charge steering" "charge switching" or "polarity swapping" as employed in "light chain charge steering" and as used herein refers to modification to multispecific antibodies where a heavy chain / light chain pair in one binding arm incorporate charge-complimentary amino acid modifications such to encourage correct light chain / heavy chain pairing and / or reduce wrong light chain / heavy chain pairing (also termed mispairing). Examples such heavy chain / light pair modifications are further described in EP2543680A1

[0221] The term "valency" as used herein refers to the number of antigen binding sites on a single antibody molecule. The antibody components of the invention may be described as "multivalent", since they possess at least two antigen binding sites on each immunoconjugate. For example, the valency of a full human IgG antibody is 2, because it has two antigen binding sites per IgG molecule and the valency of other antibodies may be higher.

[0222] The term "multivalent" as used herein is used to describe a molecule with more than one functional binding domain for any given target. For example, a multivalent immunocytokine may have more than one functional binding domain to a cytokine receptor and more than one functional binding domain to an antigen. An antibody component is multivalent if the total number of antigen binding sites is greater than 1, regardless of whether the antibody component comprises a first antigen binding site for a first antigen and a second antigen binding site for a second different antigen, or whether the antibody component comprises two antigen binding sites for the same antigen. The term "specificity" as used herein is the ability of an antibody or antibody binding domain to recognise a particular antigen as a unique molecular entity and distinguish it from another. Specificity therefore refers to the number of different types of antigens or antigenic determinants to which a particular antibody or antigen-binding fragment thereof can bind. An antibody that "specifically binds" to an antigen or an epitope is a term well understood in the art. A molecule is said to exhibit "specific binding" if it reacts more frequently, more rapidly, with greater duration and / or with greater affinity with a particular target antigen or epitope, than it does with alternative targets. An antibody that specifically binds to a particular epitope over another epitope may also be said to "selectively bind" to the first epitope. An antibody "specifically binds" to a target antigen or epitope if it binds with greater affinity, avidity, more readily, and / or with greater duration than it binds to other substances. In one embodiment, the extent of binding of an antibody to an unrelated target is less than about 10% of the binding of the antibody to the target as measured, e.g. by a radioimmunoassay (RIA) or ELISA.

[0223] As described above, gamma (g) delta (d) T-cell Receptors (gamma delta TCRs) are heterodimeric receptors comprising a gamma chain and a delta chain. The gamma chain and the delta chain each comprise a variable region and a constant region, and the classification of the various chains is explained in detail above in the section headed "Gamma Delta TCRs".

[0224] An antibody "fragment" (also referred to as "antigen-binding fragment") refers to a part of an antibody that binds to the intended target even though it is not a full immunoglobulin chain. For example, the following non-exhaustive list includes examples of antigen-binding fragments of an antibody:

[0225] (i) a Fab fragment (a monovalent fragment consisting of the VL, VH, CL and CHI domains); (ii) a F(ab')2 fragment (a bivalent fragment consisting of two Fab fragments linked by a disulphide bridge at the hinge region);

[0226] (iii) a Fd fragment (consisting of the VH and CHI domains);

[0227] (iv) a Fv fragment (consisting of the VL and VH domains of a single arm of an antibody); (v) a single chain variable fragment, scFv (consisting of VL and VH domains joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules);

[0228] (vi) a VH (an immunoglobulin chain variable domain consisting of a VH domain);

[0229] (vii) a VL (an immunoglobulin chain variable domain consisting of a VL domain);

[0230] (viii) a domain antibody (dAb, consisting of either the VH or VL domain);

[0231] (ix) a minibody (consisting of a pair of scFv fragments which are linked via CH3 domains); and (x) a diabody (consisting of a noncovalent dimer of scFv fragments that consist of a VH domain from one antibody connected by a small peptide linker a VL domain from another antibody).

[0232] In some embodiments, the antigen-binding fragment is not a VHH domain or single domain antibody.

[0233] Antibodies or antigen-binding fragments thereof of the invention may be of any class. For example, they may be IgG, IgA, IgM, IgE, IgD or isotypes thereof. Antibodies and antigen-binding fragments thereof of the invention may comprise a kappa light chain or a lambda light chain. In some embodiments, the antibody or antigen-binding fragment thereof is an IgG antibody, such as an IgG2, IgG3, IgG4 or preferably an IgG1 antibody.

[0234] In some embodiments, the antibody or antigen-binding fragment thereof comprises a hinge disabled Fc region. In some embodiments, the antibody or antigen-binding fragment thereof comprises L235A and G237A mutations (according to Eu numbering).

[0235] In some embodiments, the antibody or antigen-binding fragment thereof of the invention comprises a VH and VL domain.

[0236] In some embodiments, the CDRs (as defined by any applicable scheme such as for example Kabat, Eu, IMGT, Chothia) of the antibody or antigen-binding fragment thereof of the invention do not comprise a cysteine.

[0237] In some embodiments, the antibody or antigen-binding fragment does not comprise a non-canonical cysteine-cysteine bridge or disulfide bond.

[0238] In some embodiments, the constant domain bound by the antibody or antigen-binding fragment is TRDC or a fragment thereof and / or TRGC1 or a fragment thereof and / or TRGC2 or a fragment thereof.

[0239] In some embodiments, the constant domain bound by the antibody or antigen-binding fragment thereof is TRDC or a fragment thereof. The constant domain may be human TRDC, or cyno TRDC, or murine TRDC, preferably human TRDC. In some embodiments, the constant domain bound by the antibody or antigen-binding fragment thereof is TRGC1 or a fragment thereof. The constant domain may be human TRGC1, or cyno TRGC, or murine TRGC1, preferably human TRGC1.

[0240] In some embodiments, the constant domain bound by the antibody or antigen-binding fragment thereof is TRGC2 or a fragment thereof. The constant domain may be human TRGC2, or cyno TRGC, or murine TRGC2, preferably human TRGC2.

[0241] In some embodiments, the constant domains bound by the antibody or antigen-binding fragment thereof are TRGC1 or a fragment thereof and TRGC2 or a fragment thereof. In some embodiments, the constant domains bound by the antibody or antigen-binding fragment thereof are TRGC1 or a fragment thereof and TRGC2 or a fragment thereof and not TRDC._The constant domains may be human TRGC1, or cyno TRGC, or murine TRGC1, and human TRGC2, or cyno TRGC, or murine TRGC2, preferably human TRGC1 and human TRGC2.

[0242] In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to a first antigen wherein a first subunit of the first antigen comprises the amino acid sequence of SEQ ID NO: 10; and the second sub-unit of the first antigen comprises the amino acid sequence of SEQ ID NO: 11 and the antibody or antigen-binding fragment thereof specifically binds to a second antigen wherein a first subunit of the second antigen comprises the amino acid sequence of SEQ ID NO: 10; and the second sub-unit of the first antigen comprises the amino acid sequence of SEQ ID NO: 12.

[0243] In some embodiments, the antibody or antigen-binding fragment thereof binds a human constant domain or fragment thereof, or a cyno constant domain or fragment thereof, or a murine constant domain or fragment thereof. The term "human constant domain" or "cyno constant domain" or "murine constant domain" refers to the constant domain of a gdTCR derived from humans, cynomolgus monkeys or mice, respectively. In some embodiments, the antibody or antigen-binding fragment thereof bind to a human constant domain or fragment thereof and does not bind to a murine constant domain or fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof binds to a human constant domain and is "cross-reactive" with a cyno constant domain. As used herein, "cross-reactive" means the antibody or antigen-binding fragment thereof binds to a human constant domain or fragment thereof and a corresponding cyno constant domain or fragment thereof. Cross-reactivity is useful in providing antibodies that can be used for pre-clinical evaluation, for example in in vivo animal studies, which is an important step in medicine development. In some embodiments, the antibody or antigen-binding fragment thereof binds to corresponding human and cyno constant domains, for example the delta constant domain or the gamma constant domains. In some embodiments the antibody or antigen-binding fragment thereof binds to human TRDC or fragment thereof and cyno TRDC or fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof binds human TRGC1 or fragment thereof and cyno TRGC or fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof binds human TRGC2 or fragment thereof and cyno TRGC or fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof binds human TRGC1 or fragment thereof, human TRGC2 or fragment thereof, and cyno TRGC or fragment thereof.

[0244] In some embodiments, the antibody or antigen-binding fragment thereof does not bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof. In some embodiments, antibodies or antigen-binding fragments thereof specifically bind to;

[0245] a. antigens comprising gdTCR constant domain sequences (SEQ ID NOs: 1 to 20) which do not also contain any V-D-J region sequence or sequences as outlined in SEQ ID NOs: 66 to 83 and;

[0246] b. antigens comprising gdTCR constant domain sequence (SEQ ID NOs: 1 to 20) which do also contain V-D-J region sequence or sequences as outlined in SEQ ID NOs: 66 to 83;

[0247] but which do not specifically bind;

[0248] c. antigens containing gdTCR V-D-J sequence or sequences as outlined SEQ ID Nos: 66 to 83 which do not also comprise gdTCR constant domain sequence (SEQ ID NOs: 1 to 20)

[0249] In this embodiment therefore the antibody or antigen-binding fragment thereof identified specifically binds only to the constant domain and does not bind to any sequence in the variable region.

[0250] In some embodiments, the antibody or antigen-binding fragment thereof is able to specifically bind to more than one constant domain. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to both TRGC1 and TRGC2. In some embodiments, the antibody or antigenbinding fragment thereof specifically binds to TRGC1 and TRGC2 and TRDC. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to both TRGC1 and TRDC. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to both TRGC2 and TRDC. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to both TRGC1 and TRGC2 and not TRDC. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to an antigen comprising or consisting of SEQ ID NO: 3 (optionally a fragment thereof comprising residues Lys11 to Phe105 of SEQ ID NO: 3). In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to an antigen comprising or consisting of SEQ ID NO: 2 (optionally a fragment thereof comprising residues Lys11 to Phe105 of SEQ ID NO: 3).

[0251] In some embodiments, the antibody or antigen-binding fragment thereof preferentially binds to one constant domain over another, or may specifically bind to only one constant domain.

[0252] In some embodiments, the antibody or antigen-binding fragment thereof preferentially binds to TRGC1 over TRGC2. As used herein, "preferentially binds" means the antibody or antigen-binding fragment binds more specifically to TRGC1 than it does to TRGC2. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRGC1 antigen that is 2-fold; or 5-fold; or 10-fold; or 50-fold; or 100-fold; or 500-fold; or 1000-fold greater than the affinity for TRGC2 antigen when measured under the same or substantially the same conditions. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRGC1 antigen that is 10-fold greater than the affinity for TRGC2 antigen when measured under the same or substantially the same conditions. Affinity can be measured by any method know in the art, for example as measured using surface plasmon resonance. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds to TRGC1 and does not specifically bind to TRGC2.

[0253] In some embodiments, the antibody or antigen-binding fragment thereof preferentially binds to TRGC2 over TRGC1. As used herein, "preferentially binds" means the antibody or antigen-binding fragment binds more specifically to TRGC2 than it does to TRGC1. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRGC2 antigen that is 2-fold; or 5-fold; or 10-fold; or 50-fold; or 100-fold; or 500-fold; or 1000-fold greater than the affinity for TRGC1 antigen when measured under the same or substantially the same conditions. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRGC2 antigen that is 10-fold greater than the affinity for TRGC1 antigen when measured under the same or substantially the same conditions. Affinity can be measured by any method know in the art, for example as measured using surface plasmon resonance. In another embodiment, the antibody or antigen-binding fragment thereof of specifically binds to TRGC2 and does not specifically bind to TRGC1. The antibodies or antigen-binding fragments thereof of this invention are capable of selectively recognising constant domains structures present in authentic heterodimeric GC1 and GC2 TCRs expressed on the surface of a T cell. Said antibodies are not dependent on contact points found elsewhere in either the N-terminal variable and VDJ domains of the receptor, or in less structured, more varied sequence found in the more C-terminal section of the constant domain. Known antibodies that bind to gamma delta TCRs may therefore be inferior in this regard. For example, it has previously been demonstrated that rodent-generated so-called pan antibodies such as IMMU510 partially compete with rodent generated so-called anti-VDl specific antibodies such as TS8.2 (eg see Figure 6 of WO17197347). Logically such competition is only possible if these two antibodies are at least partially dependent and competing for space or contact points in the intervening J- region. The presently provided antibodies are not dependent on nor do they bind to the J region. Hence in one embodiment antibodies as provided herein can still bind TRDC or TRGC constant domain sequence in the presence of IMMU510. In one embodiment antibodies provided herein do not compete with IMMU510.

[0254] In some embodiments, the antibody or antigen-binding fragment thereof preferentially binds to TRDC over TRGCl or TRGC2. As used herein, "preferentially binds" means the antibody or antigen-binding fragment binds more specifically to TRDC than it does to TRGC1 or TRGC2. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRDC antigen that is 2-fold; or 5-fold; or 10-fold; or 50-fold; or 100-fold; or 500-fold; or 1000-fold greater than the affinity for TRGC1 antigen or TRGC2 antigen when measured under the same or substantially the same conditions. In some embodiments, the antibody or antigen-binding fragment thereof has an affinity for TRDC antigen that is 10-fold greater than the affinity for TRGC1 antigen or TRGC2 antigen when measured under the same or substantially the same conditions. Affinity can be measured by any method know in the art, for example as measured using surface plasmon resonance.

[0255] In one embodiment, the antibody or antigen-binding fragment thereof specifically binds to TRDC and does not bind specifically to TRGC1 or TRGC2.

[0256] In some embodiments, the antibodies or antigen-binding fragments thereof bind to protein sequences common to both human TRDC / TRGC1 and human TRDC / TRGC2 heterodimeric complexes. For example, a TRDC sequence or a sequence that appears in both TRGC1 and TRGC2. See Figure 4 which shows alignment and identities of TRGC domains. In some embodiments, the antibodies or antigen-binding fragments thereof specifically bind to (i) human TRGC2 / TRDC heterodimeric constant domain antigen, (ii) human TRGC1 / TRDC heterodimeric constant domain antigen and cynomolgus TRGC / TRDC constant domain antigen.

[0257] In some embodiments, the antibodies or antigen-binding fragments thereof specifically bind to (i) glycosylated recombinant human TRGC2 / TRDC heterodimeric constant domain antigen, (ii) glycosylated recombinant human TRGC1 / TRDC heterodimeric constant domain antigen and glycosylated recombinant cynomolgus TRGC / TRDC constant domain antigen.

[0258] In some embodiments, the invention provides an antibody or antigen-binding fragment thereof that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof and does not specifically bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof, wherein the antibody or antigen-binding fragment thereof is a human antibody or antigen-binding fragment thereof. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds human TRDC or a fragment thereof and does not specifically bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds human TRGC1 or a fragment thereof and does not specifically bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof. In some embodiments, the antibody or antigen-binding fragment thereof specifically binds human TRGC2 or a fragment thereof and does not specifically bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof.

[0259] In some embodiments, the antibodies or antigen-binding fragments thereof do not specifically bind to:

[0260] • a Fc region

[0261] • a gdTCR transmembrane sequence;

[0262] • TRDC peri transmembrane sequence located C-terminal of position valine129 (SEQ ID NO:1);

[0263] • TRGC1 peri transmembrane sequence located C-terminal of position alanine138 (SEQ ID NO:2);

[0264] • TRGC2 peri transmembrane sequence located C-terminal of alanine154 (SEQ ID NO:3); • 'connecting region' of the gdTCR antigen located downstream and C-terminal of position Ser109 (for TRDC antigen), position Asn120 (for TRGC1) or position Asn136 (TRGC2) in the respective TRDC, TRGC1 or TRGC2 antigens; the C-terminal constant domain sequences downstream of Ser109 (for TRDC antigen), position Asn120 (for TRGC1) or position Asn136 (TRGC2) and the alpha-helix transmembrane.

[0265] Such regions may be poorly recognised by antibodies, which should bind to the constant domain of the gdTCR only.

[0266] In some embodiments, the antibody or antigen-binding fragment is isolated. The term "isolated" as used herein means an antibody that has been removed from its original environment. An isolated antibody may be used to denote an antibody that is substantially free of other antibodies that bind to different antigens. For example an isolated antibody that specifically binds one or more gamma constant domains is substantially free of antibodies that bind an antigen that is not a gamma constant domain. The term "isolated" may also be used to refer to preparations where the isolated antibody is sufficiently pure to be administered therapeutically when formulated as an active ingredient of a pharmaceutical composition, or at least 70-80% (w / w) pure, more preferably, at least 80-90% (w / w) pure, even more preferably, 90-95% pure; and, most preferably, at least 95%, 96%, 97%, 98%, 99%, or 100% (w / w) pure.

[0267] Fc-gamma receptor and reduced binding Fc domains

[0268] A "Fc region" (fragment crystallizable region, also known as "Fc domain"), as used herein refers to a portion of an antibody (or constructs that contain said portion) comprising the CH2 and CH3 domains, optionally including hinge region too. The Fc region is the C-terminal region of an immunoglobulin heavy chain, including wild-type-sequence Fc regions and modified Fc regions. An Fc region is dimeric and thus comprises paired heavy chain constant regions each comprising a CH2 and CH3 domain. Fc regions of antibodies are recognised by "Fc Receptors" (IgG-Fc-receptor, FcyR or FcR) that are expressed on the surface of certain immune cells.

[0269] The immunoconjugates of the invention comprise a human immunoglobulin Fc domain comprising a first chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; and a second chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain. The multivalent antibody or fragment thereof may further comprise a CHI domain and hinge domain such that the multivalent antibody or fragment thereof comprises a CHI domain, a hinge domain, a CH2 domain and a CH3 domain e.g. SEQ ID NO: 393. As outlined above, ADCC is an immune reaction leading to the lysis of antibody-coated target cells by immune effector cells such gamma delta T-cells, NK cells etc. This reaction is mediated by the effector cell FcR binding to the C region or Fc domain of the antibody. For recombinant human antibodies, there are a number of established ways to reduce the Fc domain binding to the FcR to reduce or disable ADCC functionality and prevent antibody mediated ADCC cytotoxicity toward the target cell. Non limiting examples include:

[0270] • Choice of isotype - For example, wild-type and / or further modified IgG4 isotypes typically bind a number of FcR with reduced affinity versus IgG1 isotypes. Hence one can reduce ADCC mediated effects by use of antibodies of IgG4 isotype or chimeric IgG (e.g. IgG1 / IgG4 wherein select residues from IgG4 are incorporated into, for example, an IgG1 Fc backbone) in order to reduce FcR binding and ADCC functionality. This approach is well summarised in Dumet et al 2019 (MAbs. 2019 Nov-Dec; 11(8): 1341 - 1350)

[0271] • Glycosylation modification: Human IgGl Asn297 (EU numbering) positioned in the CH2 domain is heavily glycosylated. However, mutation of this position (e.g. N297A) results in aglycosylated antibodies with reduced FcR binding and reduced ADCC activity.

[0272] • Mutation of critical residues in the hinge / CH2 domain of an IgG: There are a variety of established ways by which one can mutate an IgG to reduce FcR binding and ADCC activity. A non-exhaustive list of examples is provided in WO2021234402. For further guidance incorporated herein are adapted examples from this application.

[0273] Table 4 includes examples of therapeutic IgG antibodies which include combinations of mutations in the Fc region that may reduce binding to Fc-gamma-Receptors and / or Clq. WHO INN name for each molecule also included. Adapted from WO2021234402, Table 2.

[0274] TABLE 4

[0275]

[0276]

[0277] Table 5 includes Examples of individual mutations in the Fc region of human IgGl considered to result in reduced binding to FcyR. Amino acid residues are listed according to the single letter code and numbered according to the EU system. These mutations are typically incorporated in combination into an IgGl Fc domain to ensure significant reduction in FcR binding. Variants reported in this table are included if they were reported as giving reduced binding to all FC-gamma receptor or were reported as giving less than 50% binding to FC gamma Rl, FC gamma RII A and Fc gamma Rl when compared to the wild-type IgG1 Fc domain. Adapted from WO2021234402, Table 1.

[0278] TABLE 5:

[0279]

[0280]

[0281] Table 4 and 5 therefore provide a number of non-limiting ways by human antibody Fc domains can be modified resulting in an antibody with reduced binding to FcR or FcRs.

[0282] The term "Fc enabled" refers to an antibody that comprises a functional Fc region (fragment crystallizable region), i.e. a Fc region that has not been disabled by mutation or otherwise. Fc enabled of "effector enabled" antibodies demonstrate unattenuated Fc function.

[0283] In some embodiments of the invention, the antibodies disclosed herein may be Fc disabled disabled e.g. SEQ. ID NO: 394. As used herein, "Fc disabled" or "hinge disabled" refers to an antibody that does not comprise a Fc region or comprises a modified Fc region with reduced functionality. A modified Fc region is one that has been disabled by mutation or otherwise. Fc disabled antibodies demonstrate attenuated Fc function, such as reduced binding to FcR. For example, reduced binding of an Fc disabled antibody to FcR may refer to a decrease in affinity of an antibody Fc region to an FcR as measured by SPR relative to a starting wild-type IgG1 Fc domain. Reduced binding also encompasses complete loss of binding, e.g. reduction of affinity of an antibody Fc region to an FcR to zero (or below detection limit of the analytical method). The Fc disabled antibody may comprise human IGHC heavy chain sequences that have been constructed, engineered or modified to reduce binding to one or more Fc gamma receptors. For example, via IGHC hinge mutation or by construction of an antibody comprising heavy chain constant domains which are chimeric or hybrid for lgGl / lgG2A or lgGl / lgG4 IGHC sequences, or via any of the mutations shown in Tables 4 and 5 herein. In some embodiments, the Fc domain of the multivalent antibody or fragment thereof comprises a substitution with respect to a wild-type Fc sequence, wherein the substitution reduces binding of the Fc domain to an Fc receptor. In some embodiments, the substitution is a substitution at a position selected from the group consisting of L234, L235, G236, G237 and P329 (EU index numbering), optionally wherein the substitution is selected from the group consisting of L235A, G237A, P329S and P329G (EU index numbering). These listed substitutions are not intended to be limiting as the skilled person is aware of multiple alternative substitutions which are known in the art and can be utilised to disable to reduce binding of the Fc domain to an Fc receptor. In a preferred embodiment, the substitutions are L234A and L235A (LALA), optionally with P329G or P329S. In another preferred embodiment, the substitutions are L235A and G237A (LAGA) (SEQ ID NO: 394), optionally with P329G (SEQ ID NO: 410) or P329S.

[0284] In some embodiments of the invention, the antibodies disclosed herein may be Fc functional (i.e. comprise a functional Fc domain). Thus, in some embodiments of the invention, the antibodies disclosed herein are able to bind FcR through the functional Fc domain. In some embodiments, the functional Fc domain may be any of IgG1, IgG2, IgG3 or IgG4 functional Fc domains.

[0285] The multivalent antibody or fragment thereof may further comprise a CHI domain and hinge domain such that the multivalent antibody or fragment thereof comprises a CHI domain, a hinge domain, a CH2 domain and a CH3 domain and the FC domain is Fc disabled e.g. SEQ ID NO: 394 or 410.

[0286] In some embodiments, the constant domain of the multivalent antibody or fragment thereof comprises:

[0287] a) a heavy chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98%, at least 99% identity or 100% identity to a human IgGl Fc domain or to a human IgGl Fc disabled domain; and

[0288] b) a light chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98%, at least 99% identity, or 100% identity to a light chain constant Kappa domain or to a light chain constant Lambda domain.

[0289] In some embodiments, the constant domain of the multivalent antibody or fragment thereof comprises:

[0290] a) a heavy chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98%, at least 99% identity or 100% identity to a human IgGl CHl-hinge-Fc domain or to a human IgGl CHl-hinge-Fc disabled domain; and b) a light chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98%, at least 99% identity, or 100% identity to a light chain constant Kappa domain or to a light chain constant Lambda domain.

[0291] In some embodiments, the constant domain of the multivalent antibody or fragment thereof comprises:

[0292] a) a heavy chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98% or at least 99% identity to a sequence selected from the group consisting of SEQ ID NOs: 393, 394 and 410; and

[0293] b) a light chain sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98% or at least 99% identity to a sequence selected from the group consisting of SEQ ID NOs: 395 to 396.

[0294] The term "effector function" as used herein is meant to refer to one or more of interactions with Fc receptors, antibody dependent cell mediated cytotoxic activity (ADCC), complement-dependent cytotoxic activity (CDC) mediated responses, Fc-mediated phagocytosis or antibody dependent cellular phagocytosis (ADCP) and antibody recycling via the FcRn receptor.

[0295] In some embodiments of the invention, the antibodies disclosed herein exhibit reduced ADCC relative to a wild type IgGl antibody when measured by the same or substantially the same method. A subset of antibodies with reduced Fc receptor binding also exhibit measurably reduced ability to mediate ADCC reactions. "Reduced ADCC" refers to a level of ADCC that is lower than exhibited by a wild type IgGl antibody (Fc enabled) as measured, for example, by an ADCC reporter bioassay (Promega). For example, it is well known that Fc domain mutations which reduce engagement with Human Fc gamma Rl II A / CD16a result in antibodies with reduced ADCC activity. In some embodiments of the invention, the antibodies disclosed herein exhibit reduced CD16a binding relative to a wild type IgGl antibody when measured by the same or substantially the same method. Antibodies with reduced ADCC activity as referred to herein includes antibody that have reduced affinity to FcR relative to human wild-type IgGl resulting in reduced capacity to mediate ADCC reactions relative to wild-type IgGl. In some embodiments of the invention, the antibodies disclosed herein do not exhibit ADCC. Antibodies that do not exhibit ADCC refers to antibodies in which ADCC activity has been reduced to zero (or below detection limit of the analytical method) i.e. complete abolishment of ADCC functionality such that an antibody is incapable of triggering ADCC. ADCC activity can be measured by any suitable method known in the art, for example, by an ADCC reporter bioassay (Promega). Fc heterodimerisation domains

[0296] As described above, the immunoconjugates of the invention may comprise multispecific (bispecific) binders (antibody components).

[0297] Methods for generating bispecific binders are known in the art, for example Fc based bispecific binders that are formed though pairing of two distinct Fc heavy chains that are engineered to dimerize. These methods enable an Fc domain to be assembled from two different heavy chains, each fused to or comprising an antibody binding domain. The antibody binding domains can be directed to different targets to generate multi-specific binders.

[0298] The immunoconjugates may comprise an Fc domain which has been engineered to promote heterodimerization of the two heavy chains. The immunoconjugates may comprise an Fc domain wherein the CH3 domain of the first chain is engineered to heterodimerise with the CH3 domain of the second chain and / or the CH3 domain of the second chain is engineered to heterodimerise with the CH3 domain of the first chain.

[0299] The concept behind such heterodimerisation technologies is to facilitate the formation of heterodimers by the addition of complementary 'steric' variants in each chain. As used herein, the term "engineered to heterodimerise" refers to a polypeptide domain that has been altered such that it is more likely to associate with a different polypeptide domain than it is to associate with an identical polypeptide domain. In the context of a Fc domain, which comprises two heavy chains, "engineered to heterodimerise" refers to changing amino acids in each heavy chain such that different heavy chains are more likely to associate to form the heterodimeric structure than to form homodimers with the same Fc amino acid sequences. Methods to generate these asymmetric bispecific binders through heterodimerisation of two different Fc heavy chains, or fragments thereof, include but are not limited to: knobs-into-holes (KIH), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab See for example, Ridgeway et al, (1996) Protein Engineering 9:7, 617-621, Brinkman & Kontermann, (2017) mAbs, 9:2, 182-212; Klein et al (2012) mAbs 4:6, 653-663; Wang et al (2019) Antibodies, 8, 43; and Dietrich et al (2020) BBA - Proteins and Proteomics 1868 140250; each of which is incorporated herein by reference in its entirety. Examples of suitable steric variants are included in FIG. 29 of US 15 / 141,350. This is reproduced herein as Table 6, and describes non-exhaustive pairs of Fc modifications to allow for heterodimer formation and / or purification away from homodimers. The heterodimeric fusion constructs are based on the self- assembling nature of the two Fc domains, e.g., two "monomers" that assemble into a "dimer". There are a number of suitable pairs of sets of heterodimerization variants. These variants come in "pairs" of "sets". That is, one set of the pair is incorporated into the first monomer and the other set of the pair is incorporated into the second monomer. It should be noted that these sets of modifications do not necessarily contact with a one-to-one correspondence. For example, one Fc monomer may have 4 modifications in a set, whilst the partner Fc monomer may only have 2 modifications in a set. Regardless, pairs of sets form an interface between the two Fc monomers that encourages heterodimer formation and discourages homodimer formation, allowing the percentage of heterodimers that spontaneously form under biological conditions to be up to over 90%, rather than the expected 50% (25% homodimer A / A:50% heterodimer A / B:25% homodimer B / B).

[0300] One mechanism for engineering heterodimerization in Fc domains is generally referred to in the art as "knobs and holes" or "Knobs in holes" or "Ki H". This refers to amino acid engineering that creates steric influences to favour heterodimeric formation and disfavour homodimeric formation, as described in U. S. Ser. No. 61 / 596,846, Ridgway et al. (ibid); Atwell et al., (1997) J. Mol. Biol. 270:26 and U. S. Pat. No.

[0301] 8,216,805, all of which are hereby incorporated by reference in their entirety. The Figures identify a number of "monomer A-monomer B" pairs that rely on "knobs and holes". KIH generally refers to engineering the antibody constant domains, typically the CH3 domains, of two distinct heavy chains to create either a "knob" or a "hole" in each chain to promote heterodimerization and / or reduce homodimerization. For example, a knob can be formed by introducing a bulky amino acid (Tyr) at position 366 (EU numbering), while the hole can be formed by replacing a bulky amino acid (Tyr) at position 407 with a smaller one (Thr). The knob fits into the hole of the opposite chain, resulting in a stable and specific heterodimeric Fc region. To stabilize such heterodimerization, additional and complementary cysteine modification can also be included such that the resulting heterodimer included an additional cys-cys covalent bond. In addition, as described in Merchant et al., (1998) Nature Biotech. 16:677, these "knobs and hole" mutations can be combined with disulfide bonds to further 'skew' formation to heterodimerization - another commonly employed and complimentary approach. An additional mechanism that finds use in the generation of heterodimers is sometimes referred to as "electrostatic steering" as described in Gunasekaran et al., (2010) J. Biol. Chem.

[0302] 285(25):19637, hereby incorporated by reference in its entirety. This is sometimes referred to herein as "charge pairs". In this approach, electrostatics are used to skew the formation towards heterodimerization. As those in the art will appreciate, these may also have an effect on pl, and thus on purification, and thus could in some cases also be considered "pl variants". There is overlap between steric variant pairs and pl variant pairs. For further background, pl variants are of particular use if one is considering charge-change as a useful additional tool to increase the pl difference between a starting antibody species A and a starting antibody species B. In turn this also increases the charge or pl difference between the two unwanted A-A and B-B homodimers. In doing so, one can ensure the desired A-B heterodimer also has a unique and separate charge (typically sitting between the AA and BB impurities) when separated by charge. This approach can be particularly attractive when one is manufacturing proteins at a larger scale wherein typical chromatography polishing steps exploit charge to separate desired A-B heterodimer species away from less desired A-A and B-B homodimer species. For reference, an additional summary of pl variants and charge or steric complimenting variant set pairs is also provided in FIG. 37 of US 2012 / 0149876, all of which are incorporated expressly by reference herein.

[0303] Therefore, immunoconjugates may comprise a human immunoglobulin Fc domain wherein the CH3 domain of the first chain is engineered to heterodimerise with the CH3 domain of the second chain and / or the CH3 domain of the second chain is engineered to heterodimerise with the CH3 domain of the first chain. The CH3 domains may be engineered to heterodimerise by a method selected from the group consisting of knobs-into-holes ( KIH), FORCE (format chain exchange), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. Preferably, the CH3 domains may be engineered to heterodimerise by a knobs-into-holes (KIH) method. The CH3 domain of the first chain may comprise one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the CH3 domain of the second chain which may comprise one or more corresponding amino acid mutations. The first chain amino acid substitution may be referred to as the "knob" and the second chain amino acid substation may be referred to as the "hole". The CH3 domain of the first chain comprises one or more of the amino acid substitutions from the first column (Monomer A) of Table 6 and the CH3 domain of the second chain comprises one or more of the corresponding amino acid substitutions from the second column (Monomer B) of Table 6.

[0304] Table 6: Example pairs of sets of mutations (EU numbering) employed in heterodimerization (adapted from FIG. 29 of U. S. Ser. No. 15 / 141,350 inclusive of steric, pl, and skew variants).

[0305]

[0306]

[0307]

[0308]

[0309]

[0310]

[0311] Preferably, multispecific immunoconjugates may comprise a human immunoglobulin Fc domain comprising a first chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; and a second chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; wherein the CH3 domain of the first chain comprises the mutation T366W (EU numbering) and the CH3 domain of the second chain comprises the mutations T366S, L368A, and Y407V (EU numbering). The CH3 domains may further comprise one or more residues mutated to cysteine residues capable of forming a disulphide bridge between the two CH3 domains (as described in Carter (2001) DOI: 10.1016 / s0022-1759(00)00339-2, incorporated herein by reference). The CH3 domain of the first chain may comprise the mutation S354C (EU numbering) and the CH3 domain of the second chain may comprise the mutation Y349C (EU numbering). These additional disulphide mutations may be combined with the preferred Ki H mutations such that the CH3 domain of the first chain comprises the mutations S354C and T366W (EU numbering) and the CH3 domain of the second chain comprises the mutations Y349C, T366S, L368A, and Y407V (EU numbering).

[0312] Multispecific immunoconjugates of the invention may preferably comprise a human immunoglobulin Fc domain comprising a first chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; and a second chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; wherein the CH3 domain of the first chain comprises or consists of the sequence of SEQ ID NO: 425 and the CH3 domain of the second chain comprises or consists of the sequence of SEQ ID NO: 426. For reference, a wild type human CH3 domain has the sequence of SEQ ID NO: 424. These Fc domains may be used with any of the antibody binding domains described herein and / or with any of the IL-15 components described herein.

[0313] The Fc domains engineered to heterodimerize may also be Fc disabled, as described in detail above. The CH3 Ki H mutations described herein to promote heterodimerization may therefore be combined with any of the substitutions to reduce binding of the Fc domain to an Fc receptor as described herein, such as a substitution at a position selected from the group consisting of L234, L235, G236, G237 and P329 (EU index numbering), optionally wherein the substitution is selected from the group consisting of L235A, G237A, P329S and P329G (EU index numbering).

[0314] When employing CH3 modified knob-in-hole (KIH) technologies, chain pairing is important to ensure correct Fc heterodimerization for each half in the resulting asymmetric 2+1+1 or 1+1+1 formats as provided. Use of KiH ensures the Vh for Target 1 (eg the anti-gd TCR constant domain target) is preferentially contained in a multispecific antibody alongside a Vh for Target 2 (eg. the TAA target of choice). It is also recommended that this is complemented with standard CL light chain pairing or biasing approaches such as polarity / charge switching or CL-CH1 switching such to ensure Vh for Target 1 pairs with VI for Target 1 and Vh for Target 2 pairs with VI for Target 2.

[0315] Consequently, to ensure correct Vh / VI pairing, in one embodiment there is provided an immunoconjugate comprising either

[0316] a) a first light chain and a first heavy chain of an antibody which binds to the constant domain of gamma delta TCR and;

[0317] b) a second light chain and a second heavy chain of an antibody which binds to a TAA, wherein the constant domains CL and CHI of the second light and second heavy chain are replaced by each other; or

[0318] c) a first light chain and a first heavy chain of an antibody which binds to the constant domain of gamma delta TCR wherein the constant domains CL and CHI of the first light and first heavy chain are replaced by each other and;

[0319] d) a second light chain and a second heavy chain of an antibody which binds to a TAA; or

[0320] e) a first light chain and a first heavy chain of an antibody which binds to the constant domain of gamma delta TCR; and

[0321] f) a second light chain and a second heavy chain of an antibody which binds to a TAA, wherein the variable domains VI and Vh of the second light and second heavy chain are replaced by each other; or

[0322] g) a first light chain and a first heavy chain of an antibody which binds to the constant domain of gamma delta TCR wherein the variable domains VI and Vh of the first light and first heavy chain are replaced by each other; and h) a second light chain and a second heavy chain of an antibody which binds to a TAA.

[0323] In an alternative embodiment there is provided an immunoconjugate comprising at least two human Fab fragments where in a first Fab domain binds the constant domain of a gamma delta TCR and a second Fab domain binds a TAA (or DAA), and wherein the second Fab domain which binds the TAA of interest comprises a mutated Fab (refer to Kabat numbering for CHI and CL domains) comprising either;

[0324] a) a human CHI domain wherein the threonine residue at position 192 is substituted with a glutamic acid residue; and a human CL domain wherein the asparagine residue at position 137 is substituted with a lysine residue and the serine residue at position 114 is substituted with an alanine residue or;

[0325] b) a human CHI domain wherein the leucine residue at position 143 is substituted with a glutamine residue, and the serine residue at position 188 is substituted with a valine residue; and a human CL domain wherein the valine residue at position 133 is substituted with a threonine and a serine residue at position 176 is substituted with a valine or;

[0326] c) a human CHI domain wherein the leucine residue at position 124 is substituted with an alanine residue, and the leucine residue at position 143 is substituted with a glutamic acid residue; and a human CL domain wherein the valine residue at position 133 is substituted with a tryptophan residue or;

[0327] d) a human CHI domain wherein the valine residue at position 190 is substituted with an alanine residue; and a human CL domain wherein the leucine residue at position 135 is substituted with a tryptophan residue, and the asparagine residue at position 137 is substituted with an alanine residue.

[0328] In an alternative embodiment there is provided an immunoconjugate comprising at least two human Fab fragments where in a first Fab domain binds the constant domain of a gamma delta TCR and a second Fab domain binds a TAA, wherein the first Fab domain comprises a mutated Fab comprising either; a) a human CHI domain wherein the threonine residue at position 192 is substituted with a glutamic acid residue; and a human CL domain wherein the asparagine residue at position 137 is substituted with a lysine residue and the serine residue at position 114 is substituted with an alanine residue or;

[0329] b) a human CHI domain wherein the leucine residue at position 143 is substituted with a glutamine residue, and the serine residue at position 188 is substituted with a valine residue; and a human CL domain wherein the valine residue at position 133 is substituted with a threonine and a serine residue at position 176 is substituted with a valine or;

[0330] c) a human CHI domain wherein the leucine residue at position 124 is substituted with an alanine residue, and the leucine residue at position 143 is substituted with a glutamic acid residue; and a human CL domain wherein the valine residue at position 133 is substituted with a tryptophan residue or;

[0331] d) a human CHI domain wherein the valine residue at position 190 is substituted with an alanine residue; and a human CL domain wherein the leucine residue at position 135 is substituted with a tryptophan residue, and the asparagine residue at position 137 is substituted with an alanine residue.

[0332] It is therefore recognized that typically four expression cassettes are employed comprising different but paired constant domains sequences comprising two variant heavy chains and two variant lights chains. To aid correct variable domain pairing core sequences can be employed which favour correct Fab formation such that the first Fab (targeting the constant domain) and the second Fab (targeting the TAA) are primarily correctly paired even if the two light chain and two heavy chain components for the respective Fabs are all co-expressed in the same cell such as a CHO cell. In terms of constant domain paired sequences, these 4 expression cassettes are summarised below. Optionally these 4 cassettes are transfected and expressed from the same cell during production.

[0333] The Target 1 'half' of the multispecific immunoconjugate, resulting in the first and second polypeptide chains as shown in Figure 24C and 24D:

[0334] The first expressing cassette encodes the antibody heavy chain for Target 1 inclusive of the associated CHl-hinge-CH2-CH3 (or CL-hinge-CH2-CH3) constant sequence needed for pairing to its cognate light chain • The second expression cassette encodes the antibody light chain for Target 1 inclusive of the associated CL (or CHI) constant sequence needed for pairing to its cognate heavy chain

[0335] The Target 2 'half' of the multispecifc immunoconjugate, resulting in the third and fourth polypeptide chains as shown in Figure 24C and 24D:

[0336] • The first expressing cassette encodes the antibody heavy chain for Target 2 inclusive of the associated CHl-hinge-CH2-CH3 (or CL-hinge-CH2-CH3) constant sequence needed for pairing to its cognate light chain

[0337] • The second expression cassette encodes the antibody light chain for Target 2 inclusive of the associated CL (or CHI) constant sequence needed for pairing to its cognate heavy chain

[0338] It is therefore recognized that regardless of the Vh or VI sequence or sushi domain and / or IL-15 moiety incorporated, there is a core sequence guiding correct heavy and light chain pairing and to which Vh or VI sequences are then attached at the N-terminus. These core sequences specifically comprise heavy and light chain matched pairs of heavy chain constant domain sequence (CHl-hinge-CH2-CH3) and light chain constant domain sequences (CL or CHI)

[0339] Non-exhaustive examples of matched core heavy chain and light constant domain sequence pairs are enclosed in the below tables (Table 7,8) wherein each matched core heavy chain / light chain constant sequence pair is arbitrarily prefixed A, B, or C (to highlight which heavy chain CHI / constant light chain sequence is employed) and suffixed with knob or hole (to highlight which heavy chain CH3 constant sequence is employed).

[0340] Table 7

[0341]

[0342]

[0343] Table 8

[0344]

[0345] With reference to the above Tables 7 and 8, it will be recognized that to generate the final multispecific immunoconjugates in the preferred formats, one preferred embodiment avoids use of identical heavy / light core constant domain sequence matched pairs for both Target 1 and Target 2 halves of the molecule. For example, to make a multispecific immunoconjugate as described herein, if Target 1 Vh / VI sequences are attached to a core sequence pair suffixed with 'knob', then Target 2 Vh / VI sequences are preferably not also attached to a pair suffixed with 'knob' but rather employs a pair suffixed with 'hole'.

[0346] It will also be recognized that these tables describing core constant domain sequences employed in immunoconjugates of this invention are focused on an approach which employs modified or switched kappa chain constant domains to encourage correct light chain pairing. It will also be recognized that lambda constant domains are equally useful in the design of such molecules. For example, human lambda constant domain (IGLC1_HUMAN, uniport.org, SEQ ID: 328) or derivative or equivalent may instead be employed instead of a kappa constant domain (IGKC_HUMAN, uniport.org, SEQ ID: 327) or derivative. In one embodiment the immunoconjugates as provided herein incorporates a human lambda constant domain in a first Fab targeting a first target to ensure correct light chain pairing in said Fab. In a further embodiment the immunoconjugates as provided herein incorporates a human lambda constant domain in a first Fab region to the first target and also incorporates a human lambda constant domain region into a second Fab region to the second target but is so designed such that said lambda constant domain is contiguous with the VI region in only the said Fab which targets the first target. In a related embodiment a second Fab which targets a second target of the bispecific incorporates the lambda constant domain into the heavy chain wherein it replaces the CHI domain of said Fab.

[0347] To extend this further and in a similar manner, it will also be recognized that if Target 1 employs 'A' core sequence then more preferably Target 2 does not employ the same prefixed 'A' core sequence. For example, if Target 1 employs 'A' knob' then Target 2 does not employ 'A' hole but rather employs 'B hole' or 'C hole'

[0348] It will be recognized that given that there are a variety of matched sequence pairs which are nonidentical for the respective Target 1 and Target 2 there are a number of alternate options to generate the final asymmetric, multispecific immunoconjugates. Some of the examples are outlined in the following Table 9 - again the same A, B, C prefix nomenclature is included but the knob / hole suffix is abbreviated to k or h respectively.

[0349] Table 9:

[0350]

[0351]

[0352] For the equivalent examples wherein the resulting immunoconjugates exhibit reduced FcR binding the following table 10 provides example core constant domain matched pairs of sequences.

[0353] Table 10

[0354]

[0355]

[0356] In some embodiments, constant domains of the multivalent antibody or fragment thereof comprises: a) a heavy chain sequence selected from the group consisting of SEQ ID NOs: 393, 394, 410 and 442 to 453; and b) a light chain sequence selected from the group consisting of SEQ ID NOs: 395, 396, 437, 438 and 454.

[0357] In some embodiments, constant domains of the multivalent antibody or fragment thereof comprises: a) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 393 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 395;

[0358] b) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 393 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 396;

[0359] c) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 394 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 395;

[0360] d) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 394 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 396;

[0361] e) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 410 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 395;

[0362] f) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 410 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 396;

[0363] g) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 442 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 438;

[0364] h) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 443 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 438;

[0365] i) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 444 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 437;

[0366] j) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 445 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 437;

[0367] k) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 446 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 454;

[0368] l) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 447 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 454;

[0369] m) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 448 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 438;

[0370] n) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 449 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 438;

[0371] o) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 450 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 437; p) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 451 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 437;

[0372] q) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 452 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 454; or

[0373] r) a heavy chain sequence comprising or consisting of the sequence of SEQ ID NO: 453 and a light chain sequence comprising or consisting of the sequence of SEQ ID NO: 454.

[0374] The heavy and light chain sequences as paired above may be combined with any of the anti-gdTCR constant domain antibody Vh / VI chains described herein (see Table 11).

[0375] As set out above, the CH3 domains may be engineered to heterodimerise by methods other than knobs-into-holes (KIH), for example FORCE (format chain exchange), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab and further detail of immunoconjugate formats generated by such methods can be found in Example 5.

[0376] Functional properties of the antibody portion of the immunoconjugates of the invention

[0377] The antibodies or antigen binding fragments of the present invention may have an advantageous functional profile. For example, antibodies or antigen-binding fragments thereof of the invention may selectively activate and / or induce proliferation of gamma delta T cells. Antibodies or antigen-binding fragments thereof of the invention may induce downregulation of gamma delta TCRs. Antibodies or antigen-binding fragments thereof of the invention may induce, promote or increase gamma delta T cell mediated killing.

[0378] As used herein "activation" of a gamma delta T cell refers to a change in the behaviour or morphology of the gamma delta T cell resulting from exposure to an activating factor. For example, in vivo a T cell may be activated or stimulated by physical interaction of the TCR with an activating factor that is a cognate peptide presented by the major histocompatibility complex molecule expressed on the surface of an antigen-presenting cell. A gamma delta T cell can also be activated or stimulated by the physical interaction of the TCR with another activating factor, such as an antibody or antigen-binding fragment of the present invention. Changes in behaviour and morphology displayed during activation include TCR downregulation, growth and proliferation of T cells and / or effector functions such as cytokine secretion, cytotoxicity, degranulation, initiation of the cell based functions of the immune system or enzyme secretion. Activation of gamma delta T cells can be measured by any suitable method known in the art, for example quantification of T cell activation markers such as CD107a, CD25, CD69 or Ki67 via flow cytometry.

[0379] As used herein, "proliferation" of gamma delta T cells refers to an increase, growth or expansion of the number of gamma delta T cells as a result of cell division. Proliferation of gamma delta T cells can be measured by any suitable method known in the art that demonstrates a change in cell number over time, for example using a haemocytometer counting chamber, using a multi-mode cell imager or assays that measure the change in metabolic activity of cells.

[0380] As used herein, "downregulation" of gamma delta TCRs refers to the process in which activated TCRs are internalised by the T cell and retained or degraded as part of the T cell activation process. The TCRs are therefore no longer displayed on the cell surface. TCR downregulation may be a marker of T cell activation. TCR downregulation may be measured by any suitable method known in the art, such as measuring TCR expression using median fluorescence intensity measured by flow cytometry.

[0381] As used herein, "gamma delta T cell mediated cell killing" refers to direct killing of tumor or cancer cells by gamma delta T cells, for example via cytotoxic functions such as secretion of perforin or granzymes by a gamma delta T cell that has recognised a tumor or cancer cell. This is distinct from ADCC (antibody-dependent cell-mediated cytotoxicity) which refers to a cell-mediated process of killing which occurs when an immune effector cell recognises cell bound antibodies and triggers lysis and death of the target cell, typically mediated via Fc-Fcy interactions. Antibodies or antigen-binding fragments thereof of the invention may induce, promote or increase gamma delta T cell mediated killing upon binding to a gamma delta T cell. Such gamma delta T cell mediated killing does not occur via ADCC cell-mediated mechanisms. Gamma delta T cell mediated killing can be measured by any suitable method known in the art, for example target cells (such as cancer or tumor cells) may be incubated with gamma delta T cells in the presence of the antibody or antigen-binding fragment thereof of the invention. After incubation, the cell culture can be stained with a dye to distinguish between target cells that are dead or alive and the proportion of dead cells can then be measured, for example by flow cytometry methods.

[0382] In some embodiments, the antibody or antigen-binding fragment thereof of the invention specifically binds to multiple different delta chains of the gamma delta TCR, for example delta 1 positive, delta 2 positive, delta 3 positive, delta 4 positive, delta 5 positive, delta 6 positive, delta 7 positive and / or delta 8 positive gamma delta TCRs. In some embodiments, the antibody or antigen-binding fragment thereof of the invention specifically binds to delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs. In some embodiments, the antibody or antigen-binding fragments of the invention downregulates delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs. In some embodiments, the antibody or antigen-binding fragments of the invention selectively activates and / or induces proliferation of delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells. The proliferation and / or downregulation may occur in all three cell subtypes concurrently, meaning delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells can all be activated in parallel by antibodies of the invention.

[0383] In some embodiments, the antibody or antigen-binding fragment thereof of the invention specifically binds to multiple different gamma chains of the gamma delta TCR. In some embodiments, the antibody or antigen-binding fragment thereof of the invention specifically binds gamma 4 positive and gamma 9 positive gamma delta TCRs. In some embodiments, the antibody or antigen-binding fragment thereof of the invention selectively activates and / or induces proliferation of gamma 4 positive and gamma 9 positive gamma delta T cells. In some embodiments, the antibody or antigen-binding fragment thereof of the invention selectively activates and / or induces proliferation of blood resident gamma delta cells, optionally gamma 9 positive gamma delta cells or delta 2 positive gamma delta cells; and also selectively activates and / or induces proliferation of tissue resident gamma delta cells, optionally delta one positive gamma delta cells or delta 3 positive gamma delta cells.

[0384] In some embodiments, the antibody or antigen-binding fragment thereof of the invention binds delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs derived from peripheral blood mononuclear cells (PBMCs).

[0385] In some embodiments, the antibody or antigen-binding fragment thereof of the invention binds to immortalized cells expressing TRGC2 containing TCR (for example PEER cells).

[0386] In some embodiments, the antibody or antigen-binding fragment thereof of the invention binds to PEER cells expressing TRGC2 containing TCR.

[0387] PEER cells are identified by catalogue number ACC 6 in DSMZ, Leibniz Institute, Germany.

[0388] In some embodiments, the antibody or antigen-binding fragment thereof of the invention induces proliferation and / or TCR downregulation of gamma constant 1 positive cells but not gamma constant 2 positive cells. For example, an anti-TRGCl antibody will bind to TRGC1 and not to TRGC2 leading to TCR downregulation of TCRs comprising TRGC1 and not those comprising TRGC2 and / or proliferation of cells comprising TRGC1 positive TCRs and not those comprising TRGC2 positive TCRs.

[0389] In some embodiments, the antibody or antigen-binding fragment thereof of the invention induces proliferation and / or TCR downregulation of gamma constant 2 positive cells but not gamma constant 1 positive cells. For example, an anti-TRGC2 antibody will bind to TRGC2 and not to TRGC1 leading to TCR downregulation of TCRs comprising TRGC2 and not those comprising TRGC1 and / or proliferation of cells comprising TRGC2 positive TCRs and not those comprising TRGC1 positive TCRs.

[0390] In some embodiments, the antibody or antigen-binding fragment thereof of the invention induces a greater than 150-fold, 200-fold, 300-fold, 450-fold or 460-fold proliferation in the number of gamma delta T cells. In some embodiments, the antibody or antigen-binding fragment thereof of the invention induces a greater than 150-fold, 200-fold, 300-fold, 450-fold or 460-fold proliferation in the number of Vδ3 gamma delta T cells.

[0391] The TCR downregulation, T cell activation and / or T cell proliferation may take place when the antibodies or antigen-binding fragments of the invention are administered to gamma delta T cells in human blood, a human blood sample or derived cells or when administered to a patient.

[0392] The immunoconjugates, antibodies or antigen-binding fragments of the invention target all γδ T cells, both blood and tissue resident. This differentiated technology enables circumvention of heterogeneity and fully enables γδ T cell activity across the broadest range of patients. Blood resident γδ T cells (typically V62 enriched) are activated by antibodies of the invention, which may trigger cytokine release, immune licensing and migration of these γδ T cells out of blood circulation and into tumours. Tissue / tumour resident γδ T cells (typically Vδ1 and Vδ3 enriched that may be tissue adapted e.g. to hypoxia) are also activated by antibodies of the invention, which may also trigger cytokine release, immune licensing and migration of these γδ T cells out of the tissues and into tumours.

[0393] In some embodiments, the antibody or antigen-binding fragment thereof of the invention is an IgGl antibody or fragment thereof and induces proliferation of gamma delta T cells.

[0394] In some embodiments, the antibody or antigen-binding fragment thereof of the invention is an IgGl antibody or fragment thereof and activates gamma delta T-cells to kill THP-1 cells in a co-culture assay. Sequences of antibody components of immunoconjugates provided herein

[0395] To outline the applicability of the approach a series of non-limiting example immunoconjugates are provided herein. These immunoconjugates comprise an antibody or antigen-binding fragment thereof comprising: a first antibody binding domain that specifically binds to one or more constant domains of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof; and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof.

[0396] A summary of some of the antibodies and antigen-binding fragments thereof of the immunoconjugates provided by the present invention is provided below with reference to the SEQ ID NO corresponding to the accompanying sequence listing. Sequences are provided in the attached sequence listing and the accompanying Figures. In the case of any discrepancy between the sequences in the sequence listing and those in Figure 18, the sequences in Figure 18 should prevail. Table 11 provides a summary of antibody portions of the immunoconjugates of the invention and their SEQ ID Nos. It is to be understood that any of the antibodies described in Table 11 can be formatted as a monospecific, bispecific or multispecific antibody.

[0397] In any aspect, the heavy chain constant domain of the antibody or antigen-binding fragment thereof may comprise or consist of the amino acid sequence of SEQ ID NO: 326 or 389.

[0398] As will be understood, any of the antibodies or antigen-binding fragments thereof may be suitably combined with the various IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into the different arrangements and formats of immunoconjugate described herein.

[0399] TABLE 11

[0400]

[0401]

[0402] Clone 6 (CYTA001):

[0403] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as Clone 6 (CYTA001) may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as Clone 6 (CYTA001) may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0404] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0405] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ. ID NO: 152; a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 153; and

[0406] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 154; and / or

[0407] a light chain variable region comprising:

[0408] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 155;

[0409] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 156; and

[0410] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 157.

[0411] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 152, 153 and 154, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID Nos: 155, 156 and 157, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 94 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 95, such that any sequence variations occur outside the CDR regions.

[0412] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 94 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 95. In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 94 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 95.

[0413] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0414] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 329 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 330. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 329 and SEQ ID NO: 330.

[0415] Clone 38 (CYTA002):

[0416] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as Clone 38 (CYTA002) may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as Clone 38 (CYTA002) may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non- covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0417] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0418] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 158;

[0419] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 159; and

[0420] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 160; and / or

[0421] a light chain variable region comprising:

[0422] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 161;

[0423] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 162; and

[0424] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 163.

[0425] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 158, 159 and 160, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 161, 162 and 163, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 96 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 97, such that any sequence variations occur outside the CDR regions.

[0426] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 96 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 97.

[0427] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 96 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 97.

[0428] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0429] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 331 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 332. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 331 and SEQ ID NO: 332.

[0430] Clone 128 (CYTA003):

[0431] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA003 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA003 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0432] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0433] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 164;

[0434] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 165; and

[0435] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 166; and / or

[0436] a light chain variable region comprising:

[0437] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 167;

[0438] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 168; and a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 169.

[0439] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 164, 165 and 166, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 167, 168 and 169, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 98 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 99, such that any sequence variations occur outside the CDR regions.

[0440] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 98 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 99.

[0441] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 98 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 99.

[0442] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0443] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 333 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 334. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 333 and SEQ ID NO: 334.

[0444] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen.

[0445] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen and specifically binds to cynomolgus TRGC / TRDC heterodimeric constant domain antigen.

[0446] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof promotes gamma delta T cell mediated killing (optionally THP-1 cell killing in co-culture assay).

[0447] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof binds to PEER cells expressing TRGC2 positive TCRs.

[0448] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to delta 1 positive and delta 3 positive gamma delta TCRs.

[0449] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof downregulates delta 1 positive and delta 3 positive gamma delta TCRs In some embodiments of this aspect, the antibody or antigen-binding fragment thereof selectively activates and / or induces proliferation of delta 1 positive and delta 3 positive gamma delta cells.

[0450] Clone 205 (CYTA004):

[0451] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA004 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA004 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0452] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0453] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 170;

[0454] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 171; and

[0455] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 172; and / or

[0456] a light chain variable region comprising:

[0457] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 173;

[0458] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 174; and a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 175.

[0459] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 170, 171 and 172, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 173, 174 and 175, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 100 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 101, such that any sequence variations occur outside the CDR regions.

[0460] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 100 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 101.

[0461] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 100 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 101.

[0462] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0463] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 335 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 336. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 335 and SEQ ID NO: 336.

[0464] Clone 228 (CYTA005):

[0465] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA005 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA005 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0466] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0467] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 176;

[0468] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 177; and a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 178; and / or

[0469] a light chain variable region comprising:

[0470] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 179;

[0471] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 180; and

[0472] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 181.

[0473] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 176, 177 and 178, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 179, 180 and 181, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 102 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 103, such that any sequence variations occur outside the CDR regions.

[0474] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 102 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 103.

[0475] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 102 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 103. In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0476] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 337 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 338. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 337 and SEQ ID NO: 338.

[0477] Clone 303 (CYTA006):

[0478] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA006 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA006 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein. In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0479] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 182;

[0480] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 183; and

[0481] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 184; and / or

[0482] a light chain variable region comprising:

[0483] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 185;

[0484] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 186; and

[0485] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 187.

[0486] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 182, 183 and 184, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 185, 186 and 187, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 104 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 105, such that any sequence variations occur outside the CDR regions. In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 104 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 105.

[0487] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 104 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 105.

[0488] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0489] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 339 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 340. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 339 and SEQ ID NO: 340. Clone 325 (CYTA007):

[0490] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA007 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA007 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0491] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided, comprising a heavy chain variable region comprising:

[0492] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 188;

[0493] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 189; and

[0494] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 190; and / or

[0495] a light chain variable region comprising:

[0496] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 191;

[0497] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 192; and

[0498] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 193.

[0499] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 188, 189 and 190, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 191, 192 and 193, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 106 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 107, such that any sequence variations occur outside the CDR regions.

[0500] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 106 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 107.

[0501] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 106 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 107.

[0502] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0503] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 341 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 342. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 341 and SEQ ID NO: 342.

[0504] Clone 332 (CYTA008):

[0505] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA008 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA008 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0506] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0507] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 194;

[0508] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 195; and

[0509] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 196; and / or

[0510] a light chain variable region comprising:

[0511] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 197; a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 198; and

[0512] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 199.

[0513] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 194, 195 and 196, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 197, 198 and 199, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 108 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 109, such that any sequence variations occur outside the CDR regions.

[0514] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 108 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 109.

[0515] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 108 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 109.

[0516] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0517] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 343 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 344. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 343 and SEQ ID NO: 344.

[0518] Clone 487 (CYTA009):

[0519] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA009 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA009 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0520] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0521] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 200; a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 201; and

[0522] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 202; and / or

[0523] a light chain variable region comprising:

[0524] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 203;

[0525] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 204; and

[0526] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 205.

[0527] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 200, 201 and 202, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 203, 204 and 205, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 110 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 111, such that any sequence variations occur outside the CDR regions.

[0528] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 110 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 111. In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 110 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 111.

[0529] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0530] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 345 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 346. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 345 and SEQ ID NO: 346.

[0531] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen and specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen.

[0532] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen, specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen and specifically binds to cynomolgus TRGC / TRDC heterodimeric constant domain antigen.

[0533] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof promotes gamma delta T cell mediated killing (optionally THP-1 cell killing in co-culture assay).

[0534] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof binds to PEER cells expressing TRGC2 positive TCRs.

[0535] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs.

[0536] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof downregulates delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs

[0537] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof selectively activates and / or induces proliferation of delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells.

[0538] Clone 489 (CYTA010):

[0539] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA010 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA010 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0540] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising: a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 206;

[0541] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 207; and

[0542] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 208; and / or

[0543] a light chain variable region comprising:

[0544] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 209;

[0545] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 210; and

[0546] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 211.

[0547] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 206, 207 and 208, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 209, 210 and 211, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 112 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 113, such that any sequence variations occur outside the CDR regions.

[0548] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 112 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 113.

[0549] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 112 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 113.

[0550] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0551] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 347 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 348. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 347 and SEQ ID NO: 348.

[0552] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen. In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen and specifically binds to cynomolgus TRGC / TRDC heterodimeric constant domain antigen.

[0553] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof promotes gamma delta T cell mediated killing (optionally THP-1 cell killing in co-culture assay).

[0554] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to delta 2 positive gamma delta TCRs.

[0555] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof downregulates delta 2 positive gamma delta TCRs

[0556] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof selectively activates and / or induces proliferation of delta 2 positive gamma delta cells.

[0557] Clone 525 (CYTA011):

[0558] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA011 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA011 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0559] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0560] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 212; a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 213; and

[0561] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 214; and / or

[0562] a light chain variable region comprising:

[0563] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 215;

[0564] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 216; and

[0565] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 217.

[0566] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 212, 213 and 214, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 215, 216 and 217, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 114 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 115, such that any sequence variations occur outside the CDR regions.

[0567] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 114 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 115. In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 114 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 115.

[0568] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0569] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 349 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 350. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 349 and SEQ ID NO: 350.

[0570] Clone 545 (CYTA012):

[0571] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA012 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA012 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0572] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0573] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 218;

[0574] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 219; and

[0575] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 220; and / or

[0576] a light chain variable region comprising:

[0577] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 221;

[0578] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 222; and

[0579] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 223.

[0580] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 218, 219 and 220, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 221, 222 and 223, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 116 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 117, such that any sequence variations occur outside the CDR regions.

[0581] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 116 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 117.

[0582] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 116 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 117.

[0583] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0584] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 351 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 352. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 351 and SEQ ID NO: 352.

[0585] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen and specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen.

[0586] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof promotes gamma delta T cell mediated killing (optionally THP-1 cell killing in co-culture assay).

[0587] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof binds to PEER cells expressing TRGC2 positive TCRs.

[0588] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs.

[0589] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof downregulates delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs

[0590] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof selectively activates and / or induces proliferation of delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells.

[0591] Clone 567 (CYTA013):

[0592] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA013 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA013 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein. In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0593] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 224;

[0594] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 225; and

[0595] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 226; and / or

[0596] a light chain variable region comprising:

[0597] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 227;

[0598] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 228; and

[0599] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 229.

[0600] In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 224, 225 and 226, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 227, 228 and 229, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 118 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 119, such that any sequence variations occur outside the CDR regions. In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 118 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 119.

[0601] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 118 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 119.

[0602] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0603] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 353 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 354. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 353 and SEQ ID NO: 354. Clone 578 (CYTA014):

[0604] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA014 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA014 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0605] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0606] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 230;

[0607] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 231; and

[0608] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 232; and / or

[0609] a light chain variable region comprising:

[0610] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 233;

[0611] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 234; and

[0612] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 235. In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 230, 231 and 232, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 233, 234 and 235, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 120 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 121, such that any sequence variations occur outside the CDR regions.

[0613] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 120 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 121.

[0614] In this aspect the antibody or antigen-binding fragment thereof may comprise a VH comprising or consisting of the amino acid sequence of SEQ ID NO: 120 and a VL comprising or consisting of the amino acid sequence of SEQ ID NO: 121.

[0615] In this aspect the antibody or antigen-binding fragment thereof may comprise a heavy chain constant domain and a light chain constant domain. The heavy chain constant domain may be an IGHG1 human heavy chain constant domain. The heavy chain constant domain may comprise or consist of the amino acid sequence of SEQ ID NO: 326. In this aspect the antibody or antigen-binding fragment thereof may comprise a light chain constant domain. The light chain constant domain may be either a kappa (IGKC human) or a lambda (IGLC1 human) constant domain. The light chain constant domain may comprise or consist of the amino acid sequence SEQ ID NO: 327 or 328. The heavy chain constant domain may be paired with either a kappa or a lambda light chain constant domain so the constant domains of the antibody or antigen-binding fragment thereof may comprise SEQ ID NO: 326 and SEQ ID NO: 327 or SEQ ID NO: 326 and SEQ ID NO: 328.

[0616] In this aspect the antibody or antigen-binding fragment thereof may comprise a full length heavy chain comprising a heavy chain variable region and a heavy chain constant region and / or a full length light chain comprising a light chain variable region and a light chain constant region. The antibody or antigen-binding fragment thereof may comprise an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 355 and / or an amino acid sequence having at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 356. Any sequence variation may occur outside the CDR regions or outside the VH or VL regions. In one embodiment the antibody or antigen-binding fragment thereof may comprise the amino acid sequences of SEQ ID NO: 355 and SEQ ID NO: 356.

[0617] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen and specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen.

[0618] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to human TRGC2 / TRDC heterodimeric constant domain antigen, specifically binds to human TRGC1 / TRDC heterodimeric constant domain antigen and specifically binds to cynomolgus TRGC / TRDC heterodimeric constant domain antigen.

[0619] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof promotes gamma delta T cell mediated killing (optionally THP-1 cell killing in co-culture assay).

[0620] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof binds to PEER cells expressing TRGC2 positive TCRs.

[0621] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof specifically binds to delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs.

[0622] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof downregulates delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs

[0623] In some embodiments of this aspect, the antibody or antigen-binding fragment thereof selectively activates and / or induces proliferation of delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells. Clone 641 (CYTA015):

[0624] As will be understood, any of the first antibody binding domains comprising sequences from the antibody component described herein as CYTA015 may be suitably combined with any second antibody binding domain described herein. Any multivalent antibodies or antigen-binding fragments thereof comprising sequences from antibody component described herein as CYTA015 may also be suitably combined with any of the IL-15 components (at least one IL-15 receptor alpha (CD215) or a functional fragment thereof and optionally an IL-15 cytokine covalently or non-covalently associated) presented herein and the components arranged into any of the different arrangements and formats of immunoconjugate described herein.

[0625] In one aspect of the invention an antibody or antigen-binding fragment thereof is provided that may form the antibody component of the immunoconjugates of the invention, comprising a heavy chain variable region comprising:

[0626] a VHCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 236;

[0627] a VHCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 237; and

[0628] a VHCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 238; and / or

[0629] a light chain variable region comprising:

[0630] a VLCDR1 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 239;

[0631] a VLCDR2 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to SEQ ID NO: 240; and

[0632] a VLCDR3 comprising or consisting of an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identity to a SEQ ID NO: 241. In this aspect the antibody or antigen-binding fragment thereof may comprise a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO: 236, 237 and 238, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 239, 240 and 241, respectively. The antibody or antigen-binding fragment thereof may comprise a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 122 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 123, such that any sequence variations occur outside the CDR regions.

[0633] In this aspect the antibody or antigen-binding fragment thereof may a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 122 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99...

Claims

CLAIMS1) An immunoconjugate comprising:a) an antibody or antigen-binding fragment thereof comprising:(i) a first antibody binding domain that specifically binds human TRGC2 / TRDC heterodimeric constant domain antigen or a fragment or fragments thereof;b) and at least one IL-15 receptor alpha (CD215) or a functional fragment thereof.2) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment is a multispecific antibody, optionally a bispecific antibody, and further comprises:ii) a second antibody binding domain that specifically binds to a second, different target antigen than the first antibody binding domain.3) The immunoconjugate of claim 2, wherein the second antibody binding domain specifically binds to a tumour associated antigen (TAA), optionally wherein the TAA is EGFR, GPC3, CD19, CD20, CD123, CD33, 5T4, EpCAM or CAIX.4) The immunoconjugate of claim 3, wherein the TAA is EGFR and comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 474 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 475.5) The immunoconjugate of claim 4, comprising:a) a VH comprising the amino acid sequence of SEQ ID NO: 120 or 110;b) a VL comprising the amino acid sequence of SEQ ID NO: 121or 111;c) a VH comprising the amino acid sequence of SEQ ID NO: 474;d) a VL comprising the amino acid sequence of SEQ ID NO: 475; anda constant domain comprising the amino acid sequence of SEQ ID NO: 389.6) The immunoconjugate of claim 3, wherein;a) the TAA is GPC3 and comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 387 and a VL comprisingan amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 388; orb) the TAA is CD20 and comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 483 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 484c) the TAA is CD19 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 498 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 499;d) the TAA is CD19 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 500 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 501;e) the TAA is CD19 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 502 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 503;f) the TAA is CD123 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 542 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 543;g) the TAA is CD33 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 540 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 541;h) the TAA is 5T4 and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 544 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 545;i) the TAA is EpCAM and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 546 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 547; orj) the TAA is CAIX and the immunoconjugate is comprising a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 548 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 549.7) The immunoconjugate of claim 6a, comprising:(i) a VH comprising the amino acid sequence of SEQ ID NO: 120 or 110;(ii) a VL comprising the amino acid sequence of SEQ ID NO: 121 or 111;(iii) a VH comprising the amino acid sequence of SEQ ID NO: 387;(iv) a VL comprising the amino acid sequence of SEQ ID NO: 388; and(v) a constant domain comprising the amino acid sequence of SEQ ID NO: 389; orthe immunoconjugate of claim 6b, comprising:(vi) a VH comprising the amino acid sequence of SEQ ID NO: 120 or 110;(vii)a VL comprising the amino acid sequence of SEQ ID NO: 121 or 111;(viii) a VH comprising the amino acid sequence of SEQ ID NO: 483;(ix) a VL comprising the amino acid sequence of SEQ ID NO: 484; and(x) a constant domain comprising the amino acid sequence of SEQ ID NO: 389; orthe immunoconjugate of claim 6f, comprising:(i) a VH comprising the amino acid sequence of SEQ ID NO: 120 or 110;(ii) a VL comprising the amino acid sequence of SEQ ID NO: 121 or 111;(iii) a VH comprising the amino acid sequence of SEQ ID NO: 542;(iv) a VL comprising the amino acid sequence of SEQ ID NO: 543; and(v) a constant domain comprising the amino acid sequence of SEQ ID NO: 389.8) The immunoconjugate of claim 7, comprising the amino acid sequence of SEQ ID NO: 390 and SEQ ID NO: 391.9) The immunoconjugate of any preceding claim wherein the antibody or antigen-binding fragment further comprises:iii) a human immunoglobulin Fc domain comprising:a. a first chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain; andb. a second chain comprising in an N- to C- terminal direction a CH2 domain and a CH3 domain.10) The immunoconjugate of any preceding claim, wherein the at least one IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to at least one C-terminus of the Fc domain.11) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof is a human antibody or antigen-binding fragment thereof.12) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof also specifically binds TRGC1 / TRDC heterodimeric constant domain antigen or a fragment thereof, optionally human TRGC1.13) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof also specifically binds to the corresponding cynomolgus constant domain (cyno TRGC / TRDC) or fragment thereof.14) The immunoconjugate of any preceding claim, wherein the constant domain specifically bound by the antibody or antigen-binding fragment thereof comprises or consists of the amino acid sequence of any one of SEQ ID NOs: 1 to 9, optionally wherein the constant domain or fragment thereof specifically bound by the antibody or antigen-binding fragment thereof comprises an amino acid sequence that is at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99% or is 100% identical to any one of SEQ ID NOs: 10 to 20.15) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof does not specifically bind to a variable domain of a gamma delta T-cell receptor (gdTCR) or a fragment or fragments thereof.16) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof comprises:a) a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO:164, 165 and 166, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 167, 168 and 169, respectively;b) a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO:200, 201 and 202, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 203, 204 and 205, respectively;c) a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO:218, 219 and 220, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 221, 222 and 223, respectively;d) a VHCDR1, a VHCDR2 and a VHCDR3 comprising the amino acid sequences of SEQ ID NO:230, 231 and 232, respectively, and a VLCDR1, a VLCDR2 and a VLCDR3 comprising the amino acid sequences of SEQ ID NOs: 233, 234 and 235, respectively.17) The immunoconjugate of any preceding claim, wherein the antibody or antigen-binding fragment thereof comprises:a) a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 98 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 99;b) a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 110 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 111;c) a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 116 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 117;d) a VH comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 120 and a VL comprising an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity to SEQ ID NO: 121.18) The antibody or antigen-binding fragment thereof of any of claims 16 or 17, further comprising a heavy chain constant domain and a light chain constant domain, wherein the heavy chain constant domain comprises or consists of the amino acid sequence of SEQ ID NO: 326 and the light chain constant domain comprises or consists of the amino acid sequence of SEQ ID NO: 327 or SEQ ID NO: 328.19) The antibody or antigen-binding fragment thereof of any previous claim, comprising the amino acid sequences of:a) SEQ ID NO: 333 and SEQ ID NO: 334;b) SEQ ID NO: 345 and SEQ ID NO: 346;c) SEQ ID NO: 351 and SEQ ID NO: 352;d) SEQ ID NO: 355 and SEQ ID NO: 356.20) The immunoconjugate of any preceding claim, wherein:a) the at least one IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the Fc domain via direct fusion; orb) the at least one IL-15 receptor alpha (CD215) or a functional fragment thereof is covalently linked to the Fc domain via a linker (linker 1), optionally wherein the linker (linker 1) is a peptide of about 5 amino acid residues or less in length, optionally wherein the linker comprises or consists of SEQ ID NO: 403.21) The immunoconjugate of any preceding claim, whereina) the CH3 domain of the first chain is engineered to heterodimerise with the CH3 domain of the second chain, optionally wherein the CH3 domain of the first chain comprises the mutations S354C and T366W (EU numbering); and / orb) the CH3 domain of the second chain is engineered to heterodimerise with the CH3 domain of the first chain, optionally wherein the CH3 domain of the second chain comprises the mutations Y349C, T366S, L368A, and Y407V (EU numbering).22) The immunoconjugate of any preceding claim, wherein the CH3 domain of the first chain comprises or consists of the sequence of SEQ ID NO: 425 and / or the CH3 domain of the second chain comprises or consists of the sequence of SEQ ID NO: 426.23) The immunoconjugate of any preceding claim, wherein the Fc domain is Fc disabled.24) The immunoconjugate of any preceding claim, wherein the IL-15 receptor alpha (CD215) fragment(s) comprise the IL-15 receptor alpha (CD215) sushi domain, optionally wherein the IL-15 receptor alpha (CD215) sushi domain(s) is a human IL-15 receptor alpha (CD215) sushi domain(s).25) The immunoconjugate of any preceding claim, wherein the IL-15 receptor alpha (CD215) sushi domain comprises or consists of a sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 95%, at least 97%, at least 98%, at least 99% identity or 100% identity to a sequence selected from the group consisting of SEQ ID NOs: 397 to 398, 418 or 419.26) The immunoconjugate of any preceding claim, wherein the immunoconjugate comprises one IL- 15 receptor alpha (CD215) or a functional fragment thereof covalently linked to the C-terminus of the first chain or the second chain of the Fc domain.27) The immunoconjugate of any preceding claim, wherein the immunoconjugate comprises a first IL- 15 receptor alpha (CD215) or a functional fragment thereof covalently linked to the C-terminus of the first chain of the Fc domain and a second IL-15 receptor alpha (CD215) or a functional fragment thereof covalently linked to the C-terminus of the second chain of the Fc domain.28) The immunoconjugate of any preceding claim, wherein the immunoconjugate comprises one or more IL-15 cytokine(s) or fragment(s) thereof non-covalently bound to one or more IL-15 receptor alpha (CD215) or a functional fragment thereof, optionally wherein the IL-15 cytokine or fragment thereof is human.29) The immunoconjugate of any preceding claim, further comprising at least one human IL-15 cytokine or a functional fragment thereof covalently linked to the C-terminus of at least one IL-15 receptor alpha (CD215) or functional fragment thereof.30) The immunoconjugate of any previous claim, wherein:a) the IL-15 cytokine and the IL-15 receptor alpha (CD215) or functional fragment thereof are directly fused to each other; orb) the IL-15 cytokine and the IL-15 receptor alpha (CD215) or functional fragment thereof are joined by a linker (linker 2), optionally wherein the linker (linker 2) is a peptide of from about 30 to about 60 amino acid residues in length, optionally wherein the linker (linker 2) comprises or consists of SEQ ID NO: 420.31) The immunoconjugate of any preceding claim, wherein the one or more IL-15 cytokine(s) or fragment(s) thereof is an IL-15 mutein.32) The immunoconjugate of any preceding claim, wherein the one or more IL-15 mutein(s) or fragment(s) thereof comprise the sequence of SEQ ID NO: 399 comprising one or more mutations selected from Table 12.33) The immunoconjugate of any preceding claim, wherein the one or more IL-15 mutein(s) or fragment(s) from Table 12 comprises the sequence of SEQ ID NO: 473.34) The immunoconjugate of any preceding claim, wherein a heavy chain variable region (VH) of the anti-TAA antibody is a sequence of SEQ ID NO: 474 or SEQ ID NO: 387 and a light chain variable region (VL) of the anti-TAA antibody is a sequence of SEQ ID NO: 475 or SEQ ID NO: 388.35) The immunoconjugate of any preceding claim, comprising:a) a first polypeptide chain comprising, in an N- to C- terminal direction:vii. a heavy chain variable region (VH) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029;viii. a human heavy chain constant region comprising or consisting of the sequence of SEQ ID NO: 446 or SEQ ID NO: 452;ix. optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403;x. an IL-15 receptor alpha (CD215) sushi domain comprising the sequence of SEQ ID NO: 418; xi. a linker comprising or consisting of the sequence of SEQ ID NO: 420; andxii. an IL-15 cytokine comprising or consisting of SEQ ID NO: 399 optionally comprising one or more mutations from Table 12; andb) a second polypeptide chain comprising, in an N- to C-terminal direction:i. a light chain variable region (VL) of an anti-gdTCR constant domain antibody; and ii. a light constant region comprising or consisting of the sequence of SEQ ID NO: 454; and c) a third polypeptide chain comprising, in an N- to C-terminal directioni. a heavy chain variable region (VH) of an anti-TAA antibody, optionally an anti-EGFR antibody;ii. a human heavy chain constant region comprising or consisting of the sequence of SEQ ID NO: 447 or SEQ ID NO: 453;iii. optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403;iv. an IL-15 receptor alpha (CD215) sushi domain comprising the sequence of SEQ ID NO: 418; v. optionally a linker comprising or consisting of the sequence of SEQ ID NO: 420; and vi. an IL-15 cytokine comprising or consisting of SEQ ID NO: 399 optionally comprising one or more mutations from Table 12; andd) a fourth polypeptide chain comprising, in an N- to C-terminal direction:i. a light chain variable region (VL) of an anti-TAA antibody optionally an anti-EGFR antibody;andii. a light constant region comprising or consisting of the sequence of SEQ ID NO: 454.36) The immunoconjugate of any preceding claim, comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 458 b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 459; and c) a third polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 460; and d) a fourth polypeptide chain comprising the light chain sequence of SEQ ID NO 461.37) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising, in an N- to C- terminal direction:(i) a heavy chain variable region (VH) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029;(ii) a human heavy chain constant region comprising or consisting of the sequence of SEQ ID NO: 446 or SEQ ID NO: 452;(iii) optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403;(iv) an IL-15 receptor alpha (CD215) sushi domain comprising the sequence of SEQ ID NO: 418; andb) a second polypeptide chain comprising, in an N- to C-terminal direction:(i) a light chain variable region (VL) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029; and(ii) a light constant region comprising or consisting of the sequence of SEQ ID NO: 454; and c) a third polypeptide chain comprising, in an N- to C-terminal direction(i) a heavy chain variable region (VH) of an anti-TAA antibody, preferably an anti-EGFR antibody;(ii) a human heavy chain constant region comprising or consisting of the sequence of SEQ ID NO: 447 or SEQ ID NO: 453;(iii) optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403;(iv) an IL-15 receptor alpha (CD215) sushi domain comprising the sequence of SEQ ID NO:418; andd) a fourth polypeptide chain comprising, in an N- to C-terminal direction:(i) a light chain variable region (VL) of an anti-TAA antibody, preferably an anti-EGFR antibody; and(ii) a light constant region comprising or consisting of the sequence of SEQ ID NO: 454; e) optionally a fifth and sixth polypeptide chain, each comprising or consisting of a human IL-15 cytokine comprising or consisting of a sequence of SEQ ID NO: 399 optionally comprising one or more mutations from Table 12.38) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 462 b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 463; and c) a third polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 464; and d) a fourth polypeptide chain comprising the light chain sequence of SEQ ID NO 465; ande) optionally a fifth and sixth polypeptide chain, each comprising or consisting of a human IL-15 cytokine comprising or consisting of the sequence of SEQ ID NO: 399 optionally comprising one or more mutations from Table 12.39) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising, in an N- to C-terminal direction:i. a heavy chain variable region (VH) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029;ii. a human heavy chain constant region;iii. optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403; and iv. the IL-15 polypeptide comprisingi. an IL-15 receptor alpha (CD215) or a functional fragment thereof;ii. a linker comprising or consisting of the sequence of SEQ ID NO: 420; andiii. an IL-15 cytokine or mutein thereof; andb) a second polypeptide chain comprising, in an N- to C-terminal direction:i. a light chain variable region (VL) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029; andii. a human light constant region;and the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides.40) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 467; and b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 468; and the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides.41) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 469; and b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 470; and the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides.42) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising, in an N- to C-terminal direction:i. a heavy chain variable region (VH) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029;ii. a human heavy chain constant region;iii. optionally a linker comprising or consisting of the sequence of SEQ ID NO: 403; and iv. an IL-15 receptor alpha (CD215) or a functional fragment thereof; andb) a second polypeptide chain comprising, in an N- to C-terminal direction:i. a light chain variable region (VL) of an anti-gdTCR constant domain antibody described herein as CYTA001-CYTA0029; andii. a human light constant region;wherein the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides; andc) optionally a fifth and sixth polypeptide chain, each comprising or consisting of a human IL-15 cytokine or mutein thereof.43) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 471; and b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 472;and the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides andc) optionally a fifth and sixth polypeptide chain, each comprising or consisting of a human IL-15 cytokine optionally comprising or consisting of the sequence of SEQ ID NO: 399.44) The immunoconjugate of any preceding claim comprising:a) a first polypeptide chain comprising the heavy chain sequence of SEQ ID NO: 471; and b) a second polypeptide chain comprising the light chain sequence of SEQ ID NO: 472;and the immunoconjugate comprises or consists of first and second copies of said first and second polypeptides andc) optionally a fifth and sixth polypeptide chain, each comprising or consisting of a human IL-15 cytokine optionally comprising or consisting of the sequence of SEQ ID NO: 473.45) The immunoconjugate of any previous claim, wherein the antibody or antigen-binding fragment thereof induces proliferation of gamma delta T cells, optionally a greater than 460-fold proliferation of gamma delta T cells (for example greater than 460-fold proliferation of gamma delta 3 TCR positive cells), and / or downregulation of gamma delta TCRs and / or promotes gamma delta T cell mediated killing.46) The immunoconjugate of any previous claim, wherein the antibody or antigen-binding fragment thereof is Fc disabled and / or does not exhibit ADCC.47) The immunoconjugate of any previous claim, wherein the antibody or antigen-binding fragment thereof:a) specifically binds to delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs;b) downregulates delta 1 positive and delta 2 positive and delta 3 positive gamma delta TCRs;and / orc) selectively activates and / or induces proliferation of delta 1 positive and delta 2 positive and delta 3 positive gamma delta cells.48) The immunoconjugate fragment thereof of any previous claim, wherein the immunoconjugate induces proliferation and / or TCR downregulation of gamma constant 2 positive cells but not gamma constant 1 positive cells.49) A polynucleotide, pair of polynucleotides or set of polynucleotides encoding the immunoconjugate of any preceding claim.50) A vector comprising a polynucleotide, pair of polynucleotides or set of polynucleotides of claim 49.51) A host cell comprising a polynucleotide, pair of polynucleotides or set of polynucleotides of claim 49, or a vector of claim 50.52) A pharmaceutical composition comprising the immunoconjugate as defined in any one of claims 1 to 48 and a pharmaceutically acceptable diluent or carrier.53) A kit comprising the immunoconjugate as defined in any one of claims 1 to 48, or the pharmaceutical composition of claim 52, optionally further comprising an additional therapeutically active agent.54) A method of treating a disease, optionally wherein the disease is cancer or an autoimmune disease, comprising administering to a subject in need thereof a therapeutically effective amount of an immunoconjugate, pharmaceutical composition or kit of any preceding claim.

Images