Engineered proteins that engage complement factor and a protein antigen, methods, and uses thereof

Abstract

Disclosed herein are polypeptide constructs that engage a complement factor (such as C1q) and a target of interest. Various configurations of the polypeptide constructs and amino acid modifications for improved efficacy are discussed. The polypeptide constructs can be used in the treatment of a disease, for example, cancer, autoimmune diseases, obesity, neurodegenerative diseases, cardiovascular diseases, and metabolic diseases, among others.

Description

ENGINEERED PROTEINS THAT ENGAGE COMPLEMENT FACTOR AND A PROTEIN ANTIGEN, METHODS, AND USES THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to European Patent Application No.24173646.1, filed 1 May 2024, European Patent Application No. 24173650.3, filed 1 May 2024, GB Patent Application No. GB 2417959.0, filed 6 December 2024, and GB Patent Application No. GB 2417958.2, filed 6 December 2024, each of which is entirely incorporated herein by reference for all purposes. BACKGROUND

[0002] The immune system is involved in the pathogenesis of several diseases, including, but not limited to cancer, autoimmune diseases, obesity, neurodegenerative diseases, and cardiovascular diseases. At the same time, the immune system can be harnessed to treat various diseases or can be targeted to reverse disease pathogenesis. The ability to harness the immune system for therapeutic purposes has been tenuous in the field of medicine as there is a delicate balancing act of maintaining both pro-inflammatory function and anti-inflammatory function of the immune system while still targeting the root cause of the disease.

[0003] The international application WO2019 / 238674 describes single domain antibodies for complement regulation which are capable of specifically binding to an epitope of a human complement factor selected from the group consisting of C1q, C3, C4 and / or the proteolytic derivatives C3b and C4b. WO2019 / 238674 also describes bi- and multispecific constructs comprising such a single domain antibody and at least one other antigen binding region (such as a second single domain antibody), in which said second antigen-binding domain binds to another target (such as a marker that is differentially expressed in cancer cells compared to non-malignant cells, a pathogenic marker a tissue- specific marker, an organ-specific marker, such as a marker specific for lung, eye, brain or kidney). WO2019 / 238674 also describes the use of such constructs in the treatment of diseases and disorders (depending, inter alia, on the target(s) of the antigen-binding regions that are present in said constructs next to the complement-binding single domain antibody or antibodies).

[0004] The international application WO2019 / 238674 also describes a number of specific Nanobodies against C1q, including the Nanbodies called “IF75” (SEQ ID NO: 13 in WO2019 / 238674) and “IF78” (SEQ ID NO:17 in WO2019 / 238674). [Note: IF75 is also referred to herein as Nb75 (see SEQ ID NO: 2) and IF78 is also referred to herein as Nb78 (see SEQ ID NO:1)]. WO2019 / 238674 also describesthat the Nanobodies described in this application may be humanized. For Nb75, reference is also made to Pedersen et al., Front. Immunol.11:1504 (2020).

[0005] The international application WO2020 / 167919 describes bispecific antigen-binding molecules comprising an antigen-binding domain that binds to a target antigen and an antigen-binding domain that binds to a complement component (such as C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8 or C9). WO2020 / 167919 also describes the use of such bispecific antigen-binding molecules in the treatment of diseases and disorders (again depending, inter alia, on the target to which the target-binding antigen- binding domain in the molecule can bind).

[0006] The non-prepublished International application entitled “Engineered complement engaging polypeptides” in the name of applicant and filed on the same date as the present application describes improved C1q binders that comprise, compared to a wild-type C1q binder, one or more modifications resulting in reduced binding affinity to a C1q complement factor as compared to a binding affinity of said corresponding wild-type C1q binder. Some preferred C1q binders according to this International application may have a binding affinity to the C1q complement factor of from about 10 nanoMolar (nM) to about 2 microMolar (μM), as determined by biolayer interferometry, and / or may bind to the C1q complement factor with a KD from about 10 nM to about 1.5 μM, from about 50 nM to about 1.4 μM, from about 100 nM to about 1.3 μM, from about 150 nM to about 1.2 μM or from about 200 nM to about 1 μM. [Note: The aforementioned ranges are also referred to herein as the “ranges specified herein”; it being understood that this wording, when used herein, generally also include preference(s) for the subranges as mentioned herein.] This International application also describes constructs comprising such C1q binders and at least one other antigen-binding moiety that binds to a target antigen, as well as uses of such constructs in the treatment of diseases and disorders (depending, inter alia, on the target antigen(s) to which said other antigen-binding moiety / moieties can bind). Said C1q binders may also be humanized. In particular aspects, said International application describes that such C1q binders can be generated by suitably introducing one or more alanine mutations into the CDRs of a naturally occurring single domain antibody (or into the CDRs of a suitable humanized variant of a naturally occurring single domain antibody). In some specific aspects, said International application describes such C1q binders that are variants of Nb75 or Nb78 (or of humanized variants of Nb75 or Nb78).

[0007] Pedersen et al., J Immunol (2023) 211 (3): 403–413, describe that “Fc-independent recruitment of C1 by modular bispecific single-domain Abs that simultaneously bind C1q and a surface Ag [which the authors of this reference also refer to as “BiCE”] can potently activate the complement system”, resulting in “superior ability of the bispecific Abs to induce complement-dependent cytotoxicity” whichprovides “effective complement activation and cell killing” and “a modality for potent complement activation”. SUMMARY

[0008] Disclosed herein is a polypeptide construct comprising: (a) a first complement factor-engaging domain that binds to C1q; (b) an antigen-binding moiety that binds to a target protein; and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain is directly linked to the antigen-binding moiety (i.e. via a suitable linker as further described herein or alternatively directly without the presence of a suitable linker). In some embodiments the first complement factor-engaging domain is indirectly linked to the antigen-binding moiety, meaning that the first complement factor-engaging domain is linked to the second complement factor-engaging domain (i.e. via a suitable linker as further described herein or alternatively directly without the presence of a suitable linker) with said second complement factor-engaging domain being linked to the antigen-binding moiety (i.e. via a suitable linker as further described herein or alternatively directly without a suitable linker). In some embodiments the second complement factor-engaging domain is directly linked to the antigen-binding moiety (i.e. via a suitable linker as further described herein or alternatively directly without the presence of a suitable linker). In some embodiments the second complement factor-engaging domain is indirectly linked to the antigen-binding moiety, meaning that the second complement factor- engaging domain is linked to the first complement factor-engaging domain (i.e. via a suitable linker as further described herein or alternatively directly without the presence of a suitable linker) with said first complement factor-engaging domain being linked to the antigen-binding moiety (i.e. via a suitable linker as further described herein or alternatively directly without a suitable linker). In some embodiments the first complement factor-engaging domain and the second complement factor- engaging domain are directly linked to the antigen-binding moiety (in each case, and independently of each other, either via a suitable linker as further described herein or alternatively directly without the presence of a suitable linker). In some embodiments the first complement factor-engaging domain and the second complement factor-engaging domain are indirectly linked to the antigen-binding moiety, for example, a linker, or an additional protein between the first complement factor-engaging domain and the second complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain modulatesthe activity of the complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain modulate the activity of the complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain directly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain directly activate human complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain indirectly activate human complement system. In some embodiments, the second complement factor-engaging domain binds to C1q (i.e. such that both the first and the second complement factor-engaging domain binds to C1q). In some embodiments, the second complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the second complement factor-engaging domain does not directly bind C1q complement factor moiety.

[0009] In some embodiments, the first and / or second complement factor-engaging domain can be a complement factor-engaging domain that engages C1q as described further described herein, and / or as described in the International application WO2019 / 238674, and / or as described in the International application WO2020 / 167919, and / or as described in the non-prepublished International application entitled “Engineered complement engaging polypeptides”. According to a preferred but non-limiting embodiment, the first and / or second complement factor-engaging domain (and preferably both) have “reduced affinity for C1q”, by which is generally meant that said C1q binder has a binding affinity to the C1q complement factor of from about 10 nanoMolar (nM) to about 2 microMolar (μM), as determined by biolayer interferometry, in particular of about 0.1 μM to about 2 μM, as determined by biolayer interferometry. In particular, such a C1q binder may bind to the C1q complement factor with a KD from about 10 nM to about 1.5 μM, from about 50 nM to about 1.4 μM, from about 100 nM to about 1.3 μM, from about 150 nM to about 1.2 μM or from about 200 nM to about 1 μM. As described in more detail in in the co-pending non-prepublished International application entitled “Engineered complement engaging polypeptides” referred to herein, such a C1q binder “with reduced affinity for C1q” may be a variant of a naturally occurring (i.e. “wild-type”) C1q binder that comprises one or more modifications relative to said wild-type C1q binder, with said one or more modifications resulting in reduced binding affinity to a C1q complement factor as compared to a binding affinity of the corresponding wild-type C1q binder (i.e. such that said affinity falls within the ranges set out herein). For example and without limitation, as described in said co-pending International application,when the C1q binder is an ISVD such as a Nanobody, such modifications may comprise suitable mutations (such as 5 or less, for example 1, 2 or 3 and preferably 1 or 2) in CDR1, CDR2 and / or CDR3 (and in particular in CDR2 and / or CDR3, such as in CDR3) that reduce the affinity for C1q (i.e. compared to the “starting sequence”, i.e. the corresponding sequence without said modification(s)). According to one specific but non-limiting aspect, also as described in said co-pending International application, such each such mutation may comprise suitably replacing an amino acid residue in the CDRs (and in particular in CDR2 and / or CDR3, such as in CDR3) that is not alanine in the starting sequence with an alanine residue. As also described in said co-pending International application, in one particular aspect, such a C1q binder “with reduced affinity for C1q” may be a variant of Nb75 with reduced affinity for C1q compared to Nb75 or a variant of Nb78 with reduced affinity for C1q compared to Nb78 (reference is again made to the further description herein). Some specific but non- limiting examples of suitable mutations (or combination of mutations) will be clear to the skilled person based on the disclosure herein and in the co-pending International application and / or can easily be determined by the skilled person based on the disclosure herein, and may depend on the specific C1q binder that is used as the starting sequence. For example and without limitation, as illustrated in the Experimental Part, when the C1 binder is a variant of Nb78, it may be advantageous to use a suitable combination of an M33A mutation in CDR1 together with one or two suitable mutations in CDR3 (for example M33A in combination with at least T102A or S103, as further described herein). When the C1 binder is a variant of Nb75, it may be advantageous to at least include a T53G mutation.

[0010] The first and second complement factor-engaging domains may be the same or different, but in the practice of the invention it may be (and is usually) preferred that they are the same or essentially the same, in particular when the polypeptide construct is an antibody of the invention (as further described herein). The invention also relates to such antibodies of the invention (as further described herein), and in further aspects also relates to antibody heavy chains and to antibody light chains that comprise a C1q binder, which antibody heavy chains and antibody light chains are as further described herein and can be part of, and / or can be incorporated in, an antibody of the invention.

[0011] In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region. In some embodiments, the antigen-binding moiety comprises a light chain. In some embodiments, the antigen-binding moiety comprises a heavy chain. In some embodiments, also referred to herein as “antibodies of the invention”, the antigen-binding moiety is a (full-sized) antibody (i.e. comprising two heavy chains and two light chains). In some embodiments, the antigen-binding moiety may be a “heavy-chain only” antibody, such as a heavy-chain only antibody that has been obtained from a species of Camelid (see for example Hamers-Casterman et al. Nature.363 (6428): 446–8 (1993)). Insome embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor- engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen- binding moiety comprises one or more light chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different light chain of the antigen-binding moiety, for example wherein the antigen- binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different heavy chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a heavy chain and a light chain and one of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety, and the other of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminusof a light chain of the antigen-binding moiety. In some embodiments, the first complement factor- engaging domain or the second complement factor-engaging domain have a lower affinity for complement factor as compared to an affinity of the antigen-binding moiety to the target protein. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each have a lower affinity for complement factor as compared to an affinity of the antigen-binding moiety to the target protein. In some embodiments, affinity for complement factor refers to the affinity of the complement factor-engaging domain for the complement factor that is engaged by that domain, e.g., where the complement factor-engaging domain binds C1q the affinity may refer to the affinity for C1q. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each comprise a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each comprise a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain that binds to C1q comprises a VHH domain (single variable domain of a heavy chain antibody). In some embodiments, the second complement factor- engaging domain that binds to C1q comprises a VHH domain. In some embodiments, the or each VHH domain binds to the C1q complement factor with a KDof about 100 nanoMolar (nM) to about 2 milliMolar (mM). In some embodiments, the antigen-binding moiety that binds to the target is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof. In some embodiments, the antigen-binding moiety that binds to the target protein is (directly or indirectly) linked to the first complement factor- engaging domain and the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the target protein is (directly or indirectly) linked to the first complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the target protein is (directly or indirectly) linked to the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen- binding moiety that binds to the target protein is (directly or indirectly) linked to the first complement factor-engaging domain with a first linker sequence and is (directly or indirectly) linked to the secondcomplement factor-engaging domain with a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. The first linker sequence and the second linker sequence may each be independently selected from linker sequences described herein. In some embodiments, the or each linker sequence comprises from about 5 amino acids to about 30 amino acids. In some embodiments, the or each linker sequence comprises from about 15 amino acids to about 20 amino acids. In some embodiments, the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) with respect to a wildtype Fc region that improves the serum half-life as compared to the wildtype Fc region. In some embodiments, the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q. In some embodiments, the modified antigen-binding Fc comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V. Other suitable Fc mutations (and suitable combinations of Fc mutations will be clear to the skilled person based on the disclosure herein and / or can easily be determined by the skilled person (optionally after a limited degree of trial and error). In some embodiments, the polypeptide construct further comprises an albumin binding nanobody (Nb). In some embodiments, the albumin-binding Nb is directly or indirectly linked to a N-terminus of the first complement factor-engaging domain or a N-terminus of the second complement factor-engaging domain. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the antigen-binding moiety. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the Fab. In some embodiments, the polypeptide construct comprising the albumin- binding Nb has increased half-life as compared to the same polypeptide construct that lacks the albumin-binding Nb. In some embodiments, the target protein is implicated in a disease. In some embodiments, the disease is a cancer, an autoimmune disease, an inflammatory disease, or a neurological disease. In some embodiments, the target protein is expressed on the surface of a cell. In some embodiments, the cell is a cancer cell, an immune cell, an endothelial cell, an epithelial cell, or a microbial cell. In some embodiments, the cell is a cancer cell, and wherein the cancer cell is a carcinoma cell, a breast cancer cell, an ovarian cancer cell, a gastric cancer cell, or a colon cancer cell.In some embodiments, the cell is an immune cell, and wherein the immune cell is a natural killer (NK) cell, a macrophage, a monocyte, a neutrophil, a dendritic cell, a T cell, a B cell, a mast cell, a basophil, or an eosinophil. In some embodiments, the antigen-binding moiety binds to a cancer-specific marker, an immune-specific marker, a pathogen-specific marker, a tissue-specific marker, or an organ-specific marker. In some embodiments, the antigen-binding moiety binds to a target protein that is EGFR, CD38, CD19, CD20, CD55, CD59, CD7, HER2, EGFR, EpCAM, or FOLR1. In some embodiments, the cancer-specific marker is CD38. In some embodiments, the cancer-specific marker is EGFR. In some embodiments, the polypeptide construct induces complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct does not induce complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct comprises an IgG region comprising a Fab region having the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. In some embodiments, the polypeptide construct comprises an IgG region comprising the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. Also disclosed herein is a polypeptide construct comprising: (a) a first complement factor-engaging domain; (b) an antigen-binding moiety that binds to a target protein; and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety, and wherein the first complement factor-engaging domain comprises a single variable domain of a heavy chain antibody (VHH domain). In some embodiments the first complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the second complement factor- engaging domain is directly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor- engaging domain are directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor-engaging domain are indirectly linked to the antigen-binding moiety. In some embodiments, the first complement factor- engaging domain or the second complement factor-engaging domain modulates the activity of the complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain modulate the activity of the complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain directly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain directlyactivate human complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the first complement factor-engaging domain does not directly bind C1q complement factor. In some embodiments, the second complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the second complement factor-engaging domain does not directly bind C1q complement factor. In some embodiments, the antigen binding-moiety comprises a Fab, a Fc, or an IgG region. In some embodiments, the antigen-binding moiety comprises a light chain. In some embodiments, the antigen-binding moiety comprises a heavy chain. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor- engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen- binding moiety comprises one or more light chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different light chain of the antigen-binding moiety, for example wherein the antigen- binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain or the secondcomplement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different heavy chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a heavy chain and a light chain and one of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety, and the other of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor- engaging domain or the second complement factor-engaging domain have a lower affinity for complement factor as compared to an affinity of the antigen-binding moiety to the target protein. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each have a lower affinity for complement factor as compared to an affinity of the antigen-binding moiety to the target protein. In some embodiments, affinity for complement factor refers to the affinity of the complement factor-engaging domain for the complement factor that is engaged by that domain, e.g., where the complement factor-engaging domain binds C1q the affinity may refer to the affinity for C1q. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each comprise a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain that comprises a single variable domain of a heavy chain antibody (VHH domain) binds to C1q. In some embodiments, the second complement factor-engaging domain comprises a single variable domain of a heavy chain antibody (VHH domain). In some embodiments, the or each VHH domain binds to the C1q complement factor with a KD of about 100 nM to about 2 mM. In some embodiments, the antigen-binding moiety that binds to the target is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen binding domain comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof. In some embodiments, the antigen-binding moiety that binds to the target protein is directly or indirectly linked to the firstcomplement factor-engaging domain and the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the target protein is directly or indirectly linked to the first complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the target protein is directly or indirectly linked to the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the target protein is directly or indirectly linked to the first complement factor-engaging domain with a first linker sequence and is directly or indirectly linked to the second complement factor-engaging domain with a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. The first linker sequence and the second linker sequence may each be independently selected from linker sequences described herein. In some embodiments, the or each linker sequence comprises from about 5 amino acids to about 30 amino acids. In some embodiments, the or each linker sequence comprises from about 15 amino acids to about 20 amino acids. In some embodiments, the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) with respect to a wildtype Fc region that improves the serum half-life as compared to the wildtype Fc region. In some embodiments, the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q. In some embodiments, the modified antigen-binding Fc comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V. Other suitable Fc mutations (and suitable combinations of Fc mutations will be clear to the skilled person based on the disclosure herein and / or can easily be determined by the skilled person (optionally after a limited degree of trial and error).In some embodiments, the polypeptide construct further comprises an albumin binding nanobody (Nb). In some embodiments, the albumin-binding Nb is directly or indirectly linked to a N-terminus of the first complement factor-engaging domain or a N-terminus of the second complement factor-engaging domain. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the antigen-binding moiety. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the Fab. In some embodiments, the polypeptide construct comprising the albumin-binding Nb has increased half-life as compared to the same polypeptide construct that lacks the albumin-binding Nb. In some embodiments, the target protein is implicated in a disease. In some embodiments, the disease is a cancer, an autoimmune disease, an inflammatory disease, or a neurological disease. In some embodiments, the target protein is expressed on the surface of a cell. In some embodiments, the cell is a cancer cell, an immune cell, an endothelial cell, an epithelial cell, or a microbial cell. In some embodiments, the cell is a cancer cell, and wherein the cancer cell is a carcinoma cell, a breast cancer cell, an ovarian cancer cell, a gastric cancer cell, or a colon cancer cell. In some embodiments, the cell is an immune cell, and wherein the immune cell is a natural killer (NK) cell, a macrophage, a monocyte, a neutrophil, a dendritic cell, a T cell, a B cell, a mast cell, a basophil, or an eosinophil. In some embodiments, the antigen-binding moiety binds to a cancer-specific marker, an immune-specific marker, a pathogen-specific marker, a tissue-specific marker, or an organ-specific marker. In some embodiments, the antigen-binding moiety binds to a target protein that is EGFR, CD38, CD19, CD20, CD55, CD59, CD7, HER2, EGFR, EpCAM, or FOLR1. In some embodiments, the cancer-specific marker is CD38. In some embodiments, the cancer-specific marker is EGFR. In some embodiments, the polypeptide construct induces complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct does not induce complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct comprises an IgG region comprising a Fab region having the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. In some embodiments, the polypeptide construct comprises an IgG region comprising the sequence of SEQ ID NO: 40 – SEQ ID NO: 78.

[0012] Also disclosed herein is a polypeptide construct comprising: (a) a first complement factor- engaging domain; (b) an antigen-binding moiety that binds to or modulates a cluster of differentiation 38 (CD38); and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen- binding moiety, and wherein the antigen-binding moiety is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof. In some embodiments the first complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor-engaging domain are directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor- engaging domain are indirectly linked to the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain modulates the activity of the complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain modulate the activity of the complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain directly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain directly activate human complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the first complement factor-engaging domain does not directly bind C1q complement factor. In some embodiments, the second complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the second complement factor- engaging domain does not directly bind C1q complement factor. In some embodiments, the antigen- binding moiety comprises a Fab, a Fc, or an IgG region. In some embodiments, the antigen-binding moiety comprises a light chain. In some embodiments, the antigen-binding moiety comprises a heavy chain. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor- engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different light chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a different heavy chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a heavy chain and a light chain and one of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety, and the other of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor- engaging domain or the second complement factor-engaging domain have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to CD38. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to CD38. In some embodiments, affinity for complement factor refers to the affinity of the complement factor-engaging domain for the complement factor that is engaged by that domain, e.g., where the complement factor-engaging domain binds C1q the affinity may refer to the affinity for C1q. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each comprise a single variable domain of a heavy chain (VHH)antibody. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each comprise a C1q complement factor-engaging domain. In some embodiments, the or each C1q complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the or each VHH domain binds to C1q complement factor with a KDof about 100 nM to about 2 mM. In some embodiments, the antigen-binding moiety that binds to the CD38 is directly or indirectly linked to the first complement factor-engaging domain and second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the CD38 is directly or indirectly linked to the first complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the CD38 is directly or indirectly linked to the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety that binds to the CD38 is directly or indirectly linked to the first complement factor-engaging domain with a first linker sequence and is directly or indirectly linked to the second complement factor-engaging domain with a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. The first linker sequence and the second linker sequence may each be independently selected from linker sequences described herein. In some embodiments, the or each linker sequence comprises from about 5 amino acids to about 30 amino acids. In some embodiments, the or each linker sequence comprises about 15 to about 20 amino acids. In some embodiments, the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) with respect to a wildtype Fc region that improves the serum half-life as compared to the wildtype Fc region. In some embodiments, the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q. In some embodiments, the modified antigen-binding Fc comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V. In some embodiments, the polypeptide construct further comprises an albumin binding nanobody (Nb). In some embodiments, the albumin-binding Nb is directly or indirectly linked to a N-terminus of the firstcomplement factor-engaging domain or a N-terminus of the second complement factor-engaging domain. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the antigen-binding moiety. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the Fab. In some embodiments, the polypeptide construct comprising the albumin- binding Nb has increased half-life as compared to the same polypeptide construct that lacks the albumin-binding Nb. In some embodiments, the CD38 is implicated in a disease. In some embodiments, the disease is a cancer, an autoimmune disease, an inflammatory disease, or a neurological disease. In some embodiments, the CD38 is expressed on the surface of a cell. In some embodiments, the cell is a cancer cell, an immune cell, an endothelial cell, an epithelial cell, or a microbial cell. In some embodiments, the cell is a cancer cell, and wherein the cancer cell is a carcinoma cell, a breast cancer cell, an ovarian cancer cell, a gastric cancer cell, or a colon cancer cell. In some embodiments, the polypeptide construct induces complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct does not induce complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct comprises an IgG region comprising a Fab region having the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. In some embodiments, the polypeptide construct comprises an IgG region comprising the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. Any of these polypeptide constructs comprising: (a) a first complement factor-engaging domain; (b) an antigen-binding moiety that binds to or modulates a cluster of differentiation 38 (CD38); and (c) a second complement factor-engaging domain may be used in a method of reducing side-effects associated with an IgG antibody-based therapy. Said method may result in reduction of one or more side effects as compared to the administering a comparable amount of the IgG antibody-based therapy. In some embodiments, the one or more side effects comprises allergic reactions such as hives or itching, nausea, vomiting, fatigue, fever, chills, malaise, skin rashes, low blood pressure, lethargy, or any combination thereof.

[0013] Also disclosed herein is a polypeptide construct comprising: (a) a first complement factor- engaging domain; (b) an antigen-binding fragment that binds to or modulates to an inflammation marker; and (c) a second complement factor-engaging domain, wherein the first complement factor- engaging domain and the second complement factor-engaging domain are linked to the antigen- binding moiety, and wherein the antigen-binding moiety that binds to the inflammation marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, anantigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof. In some embodiments the first complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the first complement factor- engaging domain and the second complement factor-engaging domain are directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor-engaging domain are indirectly linked to the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain modulates the activity of the complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain modulate the activity of the complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain directly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain directly activate human complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the first complement factor- engaging domain does not directly bind C1q complement factor. In some embodiments, the second complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the second complement factor-engaging domain does not directly bind C1q complement factor. For example, the second complement factor-engaging domain can bind to a transcriptional regulator of C1q complement factor. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region. In some embodiments, the antigen-binding moiety comprises a light chain. In some embodiments, the antigen-binding moiety comprises a heavy chain. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor- engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain andthe second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain of the antigen- binding moiety. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain are each directly or indirectly linked to a C-terminus of a different light chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a Fab, an Fc or an IgG region and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain are each directly or indirectly linked to a C-terminus of a different heavy chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a heavy chain and a light chain and one of the first and second complement factor-engaging domains is directly or indirectly linked to a C- terminus of a heavy chain of the antigen-binding moiety, and the other of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to the inflammation marker. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to the inflammation marker. In some embodiments, affinity for complement factor refers to the affinity of the complement factor-engaging domain for the complement factor that is engaged by that domain, e.g., where the complement factor-engaging domain binds C1q the affinity may refer to the affinity for C1q. In some embodiments, the inflammation marker is selected from the group consisting of IL-6, CRP, TNF, IL-10, IL-17, IGN-gamma, eotaxin, IP-10, MCP-1, and MIG. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each comprise a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain comprises a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each comprise a C1q complement factor-engaging domain. In some embodiments, the or each C1q complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the or each VHH domain binds to the C1q complement factor with a KDof about 100 nM to about 2 mM. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the first complement factor-engaging domain and second complement factor- engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the first complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the first complement factor-engaging domain with a first linker sequence and is directly or indirectly linked to the second complement factor-engaging domain with a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. The first linker sequence and the second linker sequence may each be independently selected from linker sequences described herein. In some embodiments, the or each linker sequence comprises at least 5 amino acids, or at least 30 amino acids. In some embodiments, the or each linker sequence comprises about 15 to about 20 amino acids. In some embodiments, the polypeptide construct has higher max cytotoxicity than daratumumab, isatuximab, or HexaBody-CD38 (GEN3014, see Hiemstra et al., EBioMedicine.2023 Jul;93:104663), as measured by a Complement Dependent Cytotoxicity (CDC) assay. In some embodiments, the polypeptide construct has higher max lysis than daratumumab, isatuximab, or HexaBody-CD38, as measured by CDC assay. In someembodiments, the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) with respect to a wildtype Fc region that improves the serum half- life as compared to the wildtype Fc region. In some embodiments, the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q. In some embodiments, the modified antigen-binding Fc comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V. In some embodiments, the polypeptide construct further comprises an albumin-binding Nb. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a N-terminus of the first complement factor-engaging domain or a N-terminus of the second complement factor-engaging domain. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the antigen-binding moiety. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the Fab. In some embodiments, the polypeptide construct comprising the albumin- binding Nb has increased half-life as compared to the same polypeptide construct that lacks the albumin-binding Nb. In some embodiments, the polypeptide construct induces complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct does not induce complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct comprises an IgG region comprising a Fab region having the sequence of SEQ ID NO: 40 – SEQ ID NO: 78. In some embodiments, the polypeptide construct comprises an IgG region comprising the sequence of SEQ ID NO: 40 – SEQ ID NO: 78.

[0014] Also disclosed herein is a polypeptide construct comprising: (a) a first complement factor- engaging domain; (b) an antigen-binding fragment that binds to or modulates to an autoimmune marker; and (c) a second complement factor-engaging domain, wherein the first complement factor- engaging domain and the second complement factor-engaging domain are linked to the antigen- binding moiety, and wherein the antigen-binding moiety that binds to the inflammation marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, anantigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof. In some embodiments the first complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is directly linked to the antigen-binding moiety. In some embodiments the second complement factor-engaging domain is indirectly linked to the antigen-binding moiety. In some embodiments the first complement factor- engaging domain and the second complement factor-engaging domain are directly linked to the antigen-binding moiety. In some embodiments the first complement factor-engaging domain and the second complement factor-engaging domain are indirectly linked to the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain modulates the activity of the complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain modulate the activity of the complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain directly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain directly activate human complement system. In some embodiments, the first complement factor-engaging domain or the second complement factor- engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain indirectly activates human complement system. In some embodiments, the first complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the first complement factor- engaging domain does not directly bind C1q complement factor. In some embodiments, the second complement factor-engaging domain directly binds C1q complement factor. In some embodiments, the second complement factor-engaging domain does not directly bind C1q complement factor. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region. In some embodiments, the antigen-binding moiety comprises a light chain. In some embodiments, the antigen- binding moiety comprises a heavy chain. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a light chain in the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, a Fc, or an IgG region, and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a light chainin the Fab or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain or the second complement factor- engaging domain is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more light chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain are each directly or indirectly linked to a C-terminus of a different light chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc, or an IgG region and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises a Fab, and Fc or an IgG region and the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain or the second complement factor-engaging domain is directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises one or more heavy chains and the first complement factor-engaging domain and the second complement factor-engaging domain are each directly or indirectly linked to a C-terminus of a heavy chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain are each directly or indirectly linked to a C-terminus of a different heavy chain of the antigen-binding moiety, for example wherein the antigen-binding moiety comprises an Fab region. In some embodiments, the antigen-binding moiety comprises a heavy chain and a light chain and one of the first and second complement factor-engaging domains is directly or indirectly linked to a C- terminus of a heavy chain of the antigen-binding moiety, and the other of the first and second complement factor-engaging domains is directly or indirectly linked to a C-terminus of a light chain of the antigen-binding moiety. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to the autoimmune marker. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each have a lower affinity for a complement factor as compared to an affinity of theantigen-binding moiety to the autoimmune marker. In some embodiments, affinity for complement factor refers to the affinity of the complement factor-engaging domain for the complement factor that is engaged by that domain, e.g., where the complement factor-engaging domain binds C1q the affinity may refer to the affinity for C1q. In some embodiments, the autoimmune marker is a target protein is implicated in multiple sclerosis, psoriasis, psoriatic arthritis, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, Sjogren's syndrome, Behcet's disease, ulcerative colitis, or Guillain- Barre syndrome. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain and the second complement factor-engaging domain each comprise a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the first complement factor-engaging domain or the second complement factor-engaging domain comprises a C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and the second complement factor- engaging domain each comprise a C1q complement factor-engaging domain. In some embodiments, the or each C1q complement factor-engaging domain comprises a VHH domain. In some embodiments, the or each VHH domain binds to C1q complement factor with a KDof about 100 nM to about 2 mM. In some embodiments, the antigen-binding Fc is directly or indirectly linked to the first complement factor-engaging domain and second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the first complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the second complement factor-engaging domain with a linker sequence. In some embodiments, the antigen-binding moiety is directly or indirectly linked to the first complement factor-engaging domain with a first linker sequence and is directly or indirectly linked to the second complement factor-engaging domain with a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. The first linker sequence and the second linker sequence may each be independently selected from linker sequences described herein. In some embodiments, the or each linker sequence comprises from about 5 amino acids to about 30 amino acids. In some embodiments, the or each linker sequence comprises from about 15 to about 20 amino acids. In some embodiments, the polypeptide construct has higher max cytotoxicity than daratumumab, isatuximab, or HexaBody-CD38, as measured by CDC assay. In some embodiments, the polypeptide construct has higher max lysis than daratumumab, isatuximab, or HexaBody-CD38, as measured by CDC assay. In some embodiments, the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) withrespect to a wildtype Fc region that improves the serum half-life as compared to the wildtype Fc region. In some embodiments, the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q. In some embodiments, the modified antigen-binding Fc comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V. In some embodiments, the polypeptide construct further comprises an albumin-binding Nb. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a N-terminus of the first complement factor-engaging domain or a N-terminus of the second complement factor-engaging domain. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a C-terminus of a heavy chain in the antigen-binding moiety. In some embodiments, the albumin-binding Nb is directly or indirectly linked to a C-terminus of a light chain or a heavy chain in the Fab that binds CD38. In some embodiments, the polypeptide construct comprising the albumin-binding Nb has increased serum half-life as compared to the same polypeptide construct that lacks the albumin-binding Nb. In some embodiments, the polypeptide construct induces complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct does not induce complement activation in the fluid phase as assessed by measuring generation of C4a. In some embodiments, the polypeptide construct comprises an IgG region comprising a Fab region having the sequence of any one of SEQ ID NO: 40 – SEQ ID NO: 78. In some embodiments, the polypeptide construct comprises an IgG region comprising the sequence of any one of SEQ ID NO: 40 – SEQ ID NO: 78.

[0015] According to one specifically preferred but non-limiting embodiment, a polypeptide construct provided by the invention is in the form of an “antibody of the invention”, as further described herein. As will be clear to the skilled person, when a polypeptide construct provided by the invention is in the form of an antibody of the invention, such a construct will generally comprise four polypeptide chains (i.e. two antibody heavy chains and two antibody light chains) which chains suitably form the structure that is characteristic of a conventional four-chain antibody (but with two C1q binders fused or linked to said antibody structure, as further described herein). As also described herein, such an antibody of the invention may comprise a naturally occurring Fc portion or a non-naturally occurring Fc portion (such as, for example and without limitation, an Fc portion that has been derived from a naturallyoccurring Fc portion but that (suitably) carries, within its sequence, one or more of the mutations referred to herein for such non-naturally occurring Fc portions). Some specific but non-limiting examples of mutations that can be present in the Fc portion of (the heavy chains that are present in) an antibody of the invention are described herein and / or listed in Table F; and for illustration purposes only Table G gives examples of such non-naturally occurring Fc regions (using the Fc of antibody 11B8 mentioned herein as a reference sequence, again for illustration purposes only). Such mutations may also be used in a suitable combination, as will be clear to the skilled person. For example and without limitation, such mutations or suitable combination of mutations may (i) alter (i.e. increase or decrease) the half-life of the antibody of the invention; (ii) alter (i.e. increase or decrease) the binding / affinity of the antibody to Fc gamma receptors; and / or (iii) alter (i.e. increase or decrease) the binding / affinity of the Fc region and / or the antibody of the invention for C1q (with but preferably essentially without affecting the affinity for C1q of the C1q binder(s) present in the antibody of the invention). These and other suitable mutations will be clear to the skilled person based on the disclosure herein.

[0016] In one aspect, the invention relates to an antibody of the invention (as further described herein) that contains a non-naturally occurring Fc region, which non-naturally occurring Fc region contains at least one mutation that alter (i.e. increase or decrease, but in particular decrease or essentially removed) the binding / affinity of the antibody to Fc gamma receptors. In particular, the invention relates to an antibody of the invention (as further described herein) that contains a non-naturally occurring Fc region, which non-naturally occurring Fc region contains at least one mutation that alter (i.e. increase or decrease, but in particular decrease or essentially removed) the binding / affinity of the antibody to Fc gamma receptors, where such mutations essentially do not affect the affinity of the antibody of the invention for C1q. Again, suitable mutations or combinations of mutations will be clear to the skilled person based on the disclosure herein or can easily be determined (optionally after a limited degree of testing) by the skilled person, and for example include K320E, Q386R) deletion of G236 and / or K326W, E333S. Reference is again made to Tables F and G. Again for illustration purposes only, Table G also gives a heavy chain sequence with a non-naturally occurring Fc domain (SEQ ID NO: 269, which is based on the heavy chain sequence of 11B8), two of which can for example be suitably combined with two of the light chains of SEQ ID NO: 270 (with each such light chain comprising a C1q binder as described herein) in order to provide an antibody of the invention).

[0017] In this respect, it should be noted that, while antibodies of the invention as described herein will generally have one or more of the following advantages:− improved ability to “activate complement on” a cell that expresses the antigen to which the antigen binding domain is directed (meaning: to trigger / recruit the complement system to mount an immune response or other reaction against such cell) compared to the same antibody without the C1q binder(s); and / or − no requirement for hexamerization upon antigen binding which is needed for efficient complement activation by IgG as described by Diebolder at al, Science.2014 Mar 14;343(6176):1260–1263. This means that more epitopes can be targeted; and / or − potential to recruit more than one C1q resulting in more potent complement activation as a C1q bispecific construct as described herein can – for example - have 3 C1q binding sites whereas an an IgG has 1; the antibodies may in addition have one or more of the following advantages (again, compared to the same antibody without the C1q binder), depending on the Fc portion that is present in the specific antibody and in particular on the Fc mutation(s) that may be present in such Fc portion: − the ability to activate complement on a cell that expresses the relevant antigen (i.e. on its surface), without binding to Fc-gamma receptors on immune cells thereby preventing effector mechanisms ADCC and ADCP (in other words, provide a degree of selectivity towards triggering CDC); or − the ability to activate complement on a cell that expresses the relevant antigen (i.e. on its surface), without preventing binding to Fc-gamma receptors on immune cells thereby allowing for additional secondary effector mechanisms including ADCC and ADCP.

[0018] According to one specifically preferred but non-limiting embodiment, a polypeptide construct provided by the invention comprises a single polypeptide chain that comprises the two C1q binders and the antigen binding domain (and optionally other suitable binding domains or binding units), which are suitably fused or linked to each other (in each case, and independently of each other, directly or via a suitable linker). It will be clear to the skilled person that, in this embodiment, the two C1q binders and the antigen binding domain (and often also the other binding domains or binding units) will all be single domain antibodies (as described herein). In particular, but without limitation, the two C1q binders and the antigen binding domain (and often also the other binding domains or binding units) may all be Nanobodies (as further described herein, and including VHH domains or ISVDs that have been derived from VHH domains). In this embodiment, the polypeptide construct provided by the invention may also comprise a binding domain or binding unit that provides the polypeptide construct with a desired and / or increased half-life. Such binding domain or binding unit will be clearto the skilled person and may in particular, but without limitation, include a binding domain or binding unit that can bind to serum albumin (for example and without limitation, a Nanobody that can bind to serum albumin, for which reference is for example made to WO 08 / 020079. According to a specific but non-limiting aspect, when a polypeptide construct provided by the invention comprises a single polypeptide chain, it may in particular be a (in the form of) a “bispecific complement engager” or “BiCE” (for which reference is made to Pedersen et al., supra), and in particular (in the form of) a BiCE that comprises two C1q binders (as further described herein) in which said C1q binders are preferably as further described in International application entitled “Engineered complement engaging polypeptides”.

[0019] Also disclosed herein is a pharmaceutical composition that comprises a polypeptide construct as described herein, and a pharmaceutically acceptable carrier or diluent. Also disclosed herein is a method of treating disease in a subject in need thereof, the method comprising: contacting a cell that expresses a target protein implicated in the disease or condition with a polypeptide construct as described herein, or a pharmaceutical composition as described herein; wherein the contacting results in complement-mediated cell death of the cell that expresses the target protein.

[0020] Also disclosed herein is a composition for use in inducing complement-mediated cell death when contacted with a target cell that expresses a disease-specific marker, the composition comprising: a polypeptide construct as described herein, or a pharmaceutical composition as described herein; wherein the contacting results in complement-mediated cell death of the target cell that expresses a disease-specific marker.

[0021] Also disclosed herein is a method of inducing complement-mediated cell death, the method comprising: contacting a target cell inflicted with a disease with a polypeptide construct as described herein, or a pharmaceutical composition as described herein; wherein the contacting results in complement-mediated cell death of the target cell that expresses a disease-specific marker. In some embodiments the method is performed in vivo. In some embodiments the method is performed in vitro or ex vivo.

[0022] Also disclosed herein is a polypeptide construct as described herein or a pharmaceutical composition as described herein for use in treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, wherein the antigen-binding moiety binds to the cancer-specific marker expressed on the cancer cell. Also disclosed herein is a method of treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, the method comprising administering to the subject a polypeptideconstruct as described herein or a pharmaceutical composition as described herein, wherein the antigen-binding moiety binds to the cancer-specific marker expressed on the cancer cell.

[0023] Also disclosed herein is a composition for use in treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, the composition comprising a polypeptide that comprises: (a) a complement factor-engaging domain that binds to human C1q complement factor with a binding affinity of about 1 μM, as determined by biolayer interferometry; and (b) an antigen-binding moiety that binds to the cancer-specific marker expressed on the cancer cell.

[0024] Also disclosed herein is a method of treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, the method comprising administering to the subject a polypeptide that comprises: (a) a complement factor-engaging domain that binds to human C1q complement factor with a binding affinity of about 1 μM, as determined by biolayer interferometry; and (b) an antigen-binding moiety that binds to the cancer-specific marker expressed on the cancer cell; wherein the administering is sufficient to treat the cancer in the subject.

[0025] Also disclosed herein is a method of reducing side-effects associated with an IgG antibody- based therapy comprising administering a polypeptide construct that comprises: (a) a first complement factor-engaging domain; (b) an IgG region that comprises a light chain and a heavy chain, wherein the IgG region comprises an antigen binding fragment (Fab) the binds to a target protein; and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are directly or indirectly linked to the IgG region that binds CD38, wherein the administering results in reduction of one or more side effects as compared to the administering a comparable amount of the IgG antibody-based therapy. In some embodiments, the one or more side effects comprises allergic reactions such as hives or itching, nausea, vomiting, fatigue, fever, chills, malaise, skin rashes, low blood pressure, lethargy, or any combination thereof. INCORPORATION BY REFERENCE

[0026] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The novel features of the present disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosed constructs are utilized, and the accompanying drawings of which:

[0028] FIG. 1A – FIG. 1E show schematics of exemplary polypeptide construct formats described herein that comprise one or more complement factor-engaging domains directly or indirectly linked to an antigen-binding moiety as described herein.

[0029] FIG. 2 depicts the activity of the exemplary polypeptide constructs as described herein in a Complement Dependent Cytotoxicity (CDC) assay with a B-cell lymphoma cell line, WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0030] FIG. 3 depicts the activity of the exemplary polypeptide constructs as described herein, and daratumumab in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs and daratumumab.

[0031] FIG.4 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells as compared to three controls (Hexabody-CD38, Daratumumab, Isatuximab). The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs and the three controls.

[0032] FIG. 5A – FIG. 5B show generation of C4 after treatment with exemplary polypeptide constructs, daratumumab, heat aggregated IgG (HAG) as a positive control, no antibody (No Ab) and Human serum albumin (HSA) used as negative controls. FIG.5A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line indicates the HSA control. FIG.5B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0033] FIG.6 shows a schematic of exemplary polypeptide constructs that comprises at least one C1q complement factor-engaging domain directly or indirectly linked to an antigen-binding fragment (Fab) as described herein.

[0034] FIG.7 depicts the activity of exemplary polypeptide constructs and Daratumumab as described herein in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs and daratumumab.

[0035] FIG.8 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells as compared to three controls (HexaBody-CD38, Daratumumab,Isatuximab). The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct, HexaBody-CD38, Daratumumab, and Isatuximab.

[0036] FIG.9 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0037] FIG. 10 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0038] FIG.11A – FIG.11B show fluid phase complement activation after treatment with exemplary polypeptide constructs, HAG as a positive control, No Ab, and HSA used as negative controls. FIG. 11A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG.11B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0039] FIG.12 shows a schematic of a polypeptide construct comprising at least one C1q complement factor-engaging domain directly or indirectly linked to an antigen-binding crystallized fragment (Fc) as described herein.

[0040] FIG.13 depicts the activity of the exemplary polypeptide constructs as described herein, and daratumumab in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct and Daratumumab.

[0041] FIG.14A – FIG.14B depict the activity of the exemplary polypeptide constructs as described herein, and daratumumab in CDC assay. FIG. 14A depicts the CDC assay in WSU cell line, the y- axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct and Daratumumab. FIG.14B depicts the CDC assay in Daudi cell line, the y- axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0042] FIG. 15 depicts the activity of the exemplary polypeptide constructs in a CDC assay with Daudi cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct.

[0043] FIG. 16 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct.

[0044] FIG.17 shows fluid phase complement activation after treatment with exemplary polypeptide constructs, HAG as a positive control, No Ab, and HSA used as negative controls. The y-axis depicts A450 normalized to HSA, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control.

[0045] FIG.18A – FIG.18B show fluid phase complement activation after treatment with exemplary polypeptide constructs, HAG as a positive control, No Ab, and HSA used as negative controls. FIG. 18A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG.18B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0046] FIG.19A – FIG.19B show fluid phase complement activation after treatment with exemplary polypeptide construct, HAG as a positive control, No Ab, and HSA used as negative controls. FIG. 19A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG.19B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0047] FIG.20 shows a schematic of a polypeptide construct comprising at least one C1q complement factor-engaging domain directly or indirectly linked to an antigen-binding immunoglobulin G (IgG) region as described herein.

[0048] FIG. 21 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay with WSU-DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct.

[0049] FIG.22A – FIG.22B depict the activity of the exemplary polypeptide constructs as described herein, and daratumumab in CDC assay. FIG. 22A depicts the CDC assay in WSU cell line, the y- axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct and Daratumumab. FIG.22B depicts the CDC assay in Daudi cell line, the y- axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0050] FIG.23 depicts the activity of the exemplary polypeptide constructs as described herein, and daratumumab in CDC assay with DOHH-2 cells. The y-axis represents cytotoxicity (%), and the x- axis represents concentration (nM) of the exemplary polypeptide construct.

[0051] FIG.24 depicts the activity of the exemplary polypeptide constructs as described herein, and Hexabody-CD38 in CDC assay with WSU cells. The y-axis represents cytotoxicity (%), and the x- axis represents concentration (nM) of the exemplary polypeptide construct.

[0052] FIG.25 depicts the activity of the exemplary polypeptide constructs as described herein, and mouse IgG2a in CDC assay with WSU cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct.

[0053] FIG.26 depicts the activity of the exemplary polypeptide construct as described herein, and the IgG region Cetuximab in CDC assay in EGFR positive A431 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct (ID: PC686-687) or cetuximab.

[0054] FIG.27 depicts the activity of the exemplary polypeptide construct as described herein, and the IgG region of Trastuzumab in CDC assay in OE19 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide construct (ID: PC910-911) or trastuzumab.

[0055] FIG.28A – FIG.28B show fluid phase complement activation after treatment with exemplary polypeptide construct, HAG as a positive control, No Ab, and HSA used as negative controls. FIG. 28A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG.28B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0056] FIG.29A – FIG.29B show fluid phase complement activation after treatment with exemplary polypeptide construct, HAG as a positive control, No Ab, and HSA used as negative controls. FIG. 29A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG.29B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0057] FIG.30 depicts the activity of the exemplary polypeptide constructs as described herein, the Fab of Daratumumab, the IgG region of Daratumumab, and Daratumumab in CDC assay in WSU- DLCL2 cells. The y-axis represents cytotoxicity (%), and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0058] FIG.31A – FIG.31B depict the activity of the exemplary polypeptide constructs as described herein in CDC assay in WSU cells. FIG.31A depicts a line graph with cytotoxicity (%) on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs. FIG. 31Bdepicts bar graphs with cytotoxicity (%) on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0059] FIG. 32 depicts the activity of the exemplary polypeptide constructs as described herein in CDC assay in WSU cells. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0060] FIG. 33A – FIG. 33D depict fluid phase complement activation after treatment with exemplary polypeptide constructs, HAG as a positive control, No Ab, and HSA used as negative controls. FIG.33A depicts A450 normalized to HSA on the y-axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG. 33B depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control. FIG. 33C depicts A450 normalized to HSA on the y- axis, each bar on the x-axis represents an experimental condition; the dashed line represents the HSA control. FIG. 33D depicts C4a concentration (μg / mL) on the y-axis, and x-axis represents an experimental condition, the dashed line indicates C4a concentration in HSA control.

[0061] FIGS. 34A-FIG. 34B shows exemplary constructs and complement dependent cytotoxicity (CDC) of CD38 targeting polypeptide constructs against a B-cell lymphoma cell line (WSU-DLCL2) in 10% normal human serum (NHS). FIG.34A shows CM1233-1234, CM1232-1235, and CM1232- 1236. FIG.34B depicts the activity of the exemplary polypeptide constructs in FIG.34A as described herein in CDC assay in WSU cells. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0062] FIGS. 35A-FIG. 35B shows exemplary constructs and complement dependent cytotoxicity (CDC) of CD38 targeting polypeptide constructs against a B-cell lymphoma cell line (WSU-DLCL2) in 10% normal human serum (NHS). FIG.35A shows CM1240-1241, CM1239-1242, CM1239-1244. FIG.35B depicts the activity of the exemplary polypeptide constructs in FIG.35A as described herein in CDC assay in WSU cells. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0063] FIGS. 36A- FIG. 36B shows exemplary constructs and complement dependent cytotoxicity (CDC) of CD38 targeting polypeptide constructs against a B-cell lymphoma cell line (WSU-DLCL2) in 10% normal human serum (NHS). FIG. 36 shows CM1247-1248, CM1246-1250, and CM1246- 1251. FIG.36B depicts the activity of the exemplary polypeptide constructs in FIG.36A as described herein in CDC assay in WSU cells. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0064] FIG. 37A- FIG. 37B shows an exemplary CD38-targeting polypeptide construct and complement dependent cytotoxicity (CDC) against a DOHH2 a B-cell lymphoma cell line in 10% normal human serum (NHS). FIG.37A shows CM91-751. FIG.37B depicts the activity of the CM91- 751 construct in FIG. 37A as described herein in a CDC assay in DOHH2 cells relative to daratumumab monoclonal antibody, a CD38 targeting HexaBody, and the classical bispecific polypeptide targeting C1q and CD38. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0065] FIG. 38A-FIG. 38B shows exemplary CD20-targeting polypeptide constructs and CDC against human B cells in 10% C1q depleted human serum, with cyno C1q added. FIG. 38A shows CM1475-1234, CM1684-1686, and CM1684-1686. FIG. 38B depicts the activity of the exemplary polypeptide constructs in FIG.38A as described herein in CDC assay in WSU cells. Cytotoxicity (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs. A Genmab 11B8 CD20-targeting antibody served as a control.

[0066] FIG.39 shows antibody-dependent cellular cytotoxicity (ADCC) activity of CD38-targeting polypeptide construct that comprises a daratumumab heavy chain (PC91) combined with a modified daratumumab light chain. ADCC (%) is shown on the y-axis, and the x-axis represents concentration (nM) of the exemplary polypeptide constructs.

[0067] FIG. 40 shows a graph of the cytotoxicity of Daudi cells treated with CD19 mAb or CD19- BiCE at varying concentrations. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0068] FIG.41 shows a graph of the cytotoxicity of Daudi cells treated with CD20 mAb, CD20-BiCE, or Rituximab at varying concentrations. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0069] FIG. 42 shows a schematic of an exemplary CD20-BiCE and structural features of the polypeptide construct.

[0070] FIG. 43 shows a graph the cytotoxicity of human B cells treated with CD20 mAb, CD20- BiCE, or CD-20 BiCE- LALAPG at varying concentrations. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0071] FIG. 44 shows a graph of B cell depletion in human peripheral blood mononuclear cells (PBMCs) treated with CD20 mAb, CD20-BiCE, or CD-20 BiCE- LALAPG at varying concentrations. The y-axis depicts percent B cell killing, and the x-axis depicts concentration (nM).

[0072] FIG. 45 shows a graph of antibody-dependent cellular cytotoxicity (ADCC) in human peripheral plood mononuclear cells (PBMCs) treated with CD20 mAb, CD20-BiCE, or CD-20 BiCE-LALAPG at varying concentrations. The y-axis depicts percent cell lysis, and the x-axis depicts concentration (nM).

[0073] FIG.46 shows a graph of a human whole blood assay for B cell killing in human blood treated with CD20 mAb, CD20-BiCE, CD-20 BiCE- LALAPG, alemtuzumab, and cetuximab at varying concentrations. The y-axis depicts percent B cell killing, and the x-axis depicts concentration (nM).

[0074] FIG.47 shows a schematic of Non-Human Primate (NHP) evaluation, conditions, blood draw schedule, and biopsy schedule.

[0075] FIG. 48 shows a graph of CD19+ and CD20+ blood cells determined by flow cytometry in NHPs treated with CD20-BiCE (sample #: 1001, 1002, 1003) or CD20-BiCE-LALAPG (sample #: 2001, 2002, 2003). The y-axis depicts the percentage of CD19 positive or CD20 positive cells as indicated, and the x-axis depicts time in days.

[0076] FIG. 49 shows a graph of CD19+ cells determined by flow cytometry in NHP lymphnodes following treatment with CD20-BiCE (sample #: 1001, 1002, 1003) or CD20-BiCE-LALAPG (sample #: 2001, 2002, 2003). The y-axis depicts the percentage of CD19 positive cells, and the x-axis depicts time in days.

[0077] FIG.50 shows a graph of the cytotoxicity of NHP B cell populations treated with CD20 mAb, CD20-BiCE, or CD-20 BiCE- LALAPG at varying concentrations in vitro. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0078] FIG.51A- FIG.51B show graphs of B cell killing in populations of PBMCs using different concentrations of CD-20 mAb, CD20-BiCE, and CD20-BiCE-LALAPG. FIG.23A shows a graph of B cell killing in a population of non-naïve PBMCs with matched serum. FIG.23B shows a graph of B cell killing in a population of naiive PBMCs with matched serum. The percentage of B cells killed following administration to the cells was quantified for each concentration. The y-axis depicts percent B cell killing, and the x-axis depicts concentration (nM).

[0079] FIG. 52 shows a schematic of Dara-BiCE, HexaBody-CD38, daratumumab, and a BiCE negative control antibody.

[0080] FIG.53 shows a graph of the cell lysis of various cell lines treated with the Dara-IgG-BiCE. The y-axis depicts percent maximum lysis, and the x-axis depicts cell lines grouped by activity as indicated.

[0081] FIG. 54 shows a graph of the cytotoxicity of WSU-DLCL2 cells treated with Dara-BiCE, HexaBody-CD38, daratumumab, and a BiCE negative control antibody. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0082] FIG.55 shows a graph of the cytotoxicity of RAMOS cells (B cell Lymphoma) and LP-1 cells (Multiple Myeloma) treated with Dara-BiCE, HexaBody-CD38, daratumumab, and a BiCE negative control antibody. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM). A table of receptor number indicates that LP-1 cells have a high level of CD38 expression.

[0083] FIG.56 shows a heat map of protein levels and max cell lysis of cell lines treated with Dara- IgG BiCE, Daratumumab, or the CD38 hexabody.

[0084] FIG. 57 shows a graph of cytotoxicity of DOHH2 cells treated with CM91-751; CM1253- 1255 (Felzartamab); CM1267-1269 (mezagitamab); CM 1781-1782 (CM313); CM1781-1783 (CM313 + C1q binder); daratumumamb; CM220-221 (CD28 Hexabody); or isatuximab. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0085] FIG. 58 shows a graph of cytotoxicity of WSU cells treated with CM1232-1234 (daratumumamb 005); CM 1233-1234; CM1232-1235; CM1232-1236; CM1232-1237; CM1239- 1241; CM1240-1241; CM1239-1242; CM1239-1243; CM1239-1244; CM1246-1248; CM1247-1248 . The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0086] FIG. 59 shows a graph of the cytotoxic effects of additional CD38-targeting polypeptide constructs. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0087] FIG. 60 shows a graphs of the cytotoxic effects of C1q and CD38-targeting polypeptide constructs (BiCE constructs) relative to their parental monoclonal antibody. The y-axis depicts percent cytotoxicity, and the x-axis depicts concentration (nM).

[0088] FIG. 61 shows graphs of the level of plasmablast and NK cell depletion in healthy bone marrow from donor treated with Dara-BiCE. The y-axis depicts percent cells from live, and the x-axis depicts concentration (nM).

[0089] FIG. 62 shows a graph of plasma cell killing in human bone marrow samples treated with Dara-BiCE. Samples were from bone marrow samples from newly diagnosed multiple myeloma (MM) patients, a relapsing patient, and a patient with progressive MM The y-axis depicts percent plasma cell killing, and the x-axis depicts the construct.

[0090] FIG.63A-FIG.63D show graphs of an ADCC bioassay of cells treated with CD38-targeting constructs provided herein. The y-axis depicts percent lysis, and the x-axis depicts the concentration.

[0091] FIG. 64 shows a graph of C4a concentration in response to 003 Bice; MORO3080 BiCEs; meza BiCEs; and 024 BiCES relative to controls. The y-axis depicts C4a concentration (micrograms per milliliter), and the x-axis depicts the construct.

[0092] FIG. 65 shows a graph of SRG rat tumor size over time in rats treated with palivizumab (20mg / kg) or varying concentrations of Dara-BiCE.DETAILED DESCRIPTION Definitions

[0093] Unless otherwise indicated, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Reference is for example made to the standard handbooks mentioned in paragraph a) on page 46 of WO 08 / 020079 of Ablynx N.V. entitled “Amino acid sequences directed against IL-6R and polypeptides comprising the same for the treatment of diseases and disorders associated with Il-6 mediated signalling”, as well as the publications and handbooks cited therein. Unless otherwise indicated or obvious from context, the following terms have the following meanings:

[0094] Unless indicated otherwise, all methods, steps, techniques and manipulations that are not specifically described in detail can be performed and have been performed in a manner known per se, as will be clear to the skilled person. Reference is for example again made to the standard handbooks and the general background art mentioned herein and to the further references cited therein; as well as to for example the following reviews Presta, Adv. Drug Deliv. Rev.2006, 58 (5-6): 640-56; Levin and Weiss, Mol. Biosyst. 2006, 2(1): 49-57; Irving et al., J. Immunol. Methods, 2001, 248(1-2), 31-45; Schmitz et al., Placenta, 2000, 21 Suppl. A, S106-12, Gonzales et al., Tumour Biol., 2005, 26(1), 31- 43, which describe techniques for protein engineering, such as affinity maturation and other techniques for improving the specificity and other desired properties of proteins such as immunoglobulins.

[0002] Amino acid residues will be indicated according to the standard three-letter or one-letter amino acid code. Reference is made to Table A-2 on page 48 of the International application WO 08 / 020079.

[0095] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a sample” includes a plurality of samples, including mixtures thereof.

[0096] Any reference to “or” herein is intended to encompass “and / or” unless otherwise stated. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0097] Use of the term “including” as well as other forms, such as “includes” and “included,” is not limiting.

[0098] As used herein, the term “comprise” and its grammatical equivalents specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude thepresence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0099] As used herein, the term “about” in reference to a number or range of numbers is understood to mean the stated number and numbers + / - 10% thereof, or 10% below the lower listed limit and 10% above the higher listed limit for the values listed for a range, as well as variations of ±5%, ±1%, ±0.5%, or even ±0.1%.

[0100] Unless indicated otherwise, the terms “immunoglobulin sequence”, “sequence”, “nucleotide sequence” and “nucleic acid” are as described in paragraph b) on page 46 of WO 08 / 020079.

[0101] The term “antibody” refers to a polypeptide or protein capable of recognizing and binding an antigen comprising at least one antigen binding site. Said antigen binding site preferably comprises at least one complementarity determining region (CDR). The present disclosure relates primarily to single domain antibodies.

[0102] The terms “single domain antibodies”, “single variable domains” and “immunoglobulin single variable domain” (or “ISVD”), which terms are used interchangeably herein, have their understood meaning in the art and generally refer to a binding domain that comprises an immunoglobulin fold and that can form a functional antigen binding site without having to pair with another immunoglobulin-based binding domain (as is for example the case with the VH and VL domains that are present in conventional 4-chain antibodies, which need to pair with another VL or VH domain, respectively, to form a functional antigen binding site). Accordingly, single domain antibodies, single variable domains, and immunoglobulin single variable domains / ISVDs will generally comprise only one single domain or fragment of a domain of a whole antibody. The single domain may be a heavy chain constant region (CH), a heavy chain variable region (VH), a light chain constant region (CL) or a light chain variable region (VL) or a fragment thereof. In a preferred embodiment the single domain is a heavy chain variable region (VH). Different kinds of single domain antibodies / ISVD are well known in the art and for example include a "dAb" (or an amino acid sequence that is suitable for use as a dAb) or a Nanobody™ (as defined herein, and including but not limited to a VHH sequence); other single variable domains, or any suitable fragment of any one thereof. For a general description of (single) domain antibodies, reference is also made to the publications cited above, as well as to EP 0368684. For the term “dAb’s”, reference is for example made to Ward et al. (Nature 1989 Oct 12; 341 (6242): 544-6), to Holt et al., Trends Biotechnol., 2003, 21(11):484-490; as well as to for example WO 06 / 030220, WO 06 / 003388 and other published patent applications of Domantis Ltd. It should also be noted that, although less preferred in the context of thepresent invention because they are not of mammalian origin, single domain antibodies or single variable domains can be derived from certain species of shark (for example, the so-called “IgNAR domains”, see for example WO 05 / 18629). For a description of VHHs and Nanobodies, reference is made to WO 08 / 020079 and the further references cited herein. Preferably, a single domain antibody, single variable domain or immunoglobulin single variable domains / ISVD as used in the invention will be a Nanobody (including VHHs and Nanobodies of synthetic or semi-synthetic origin, in each case carrying one or more of the “Hallmark residues” that are characteristic of Nanobodies, for which reference is again made to WO 08 / 020079).

[0103] An “antigen” is a molecule comprising at least one epitope. The antigen may for example be a polypeptide, nucleic acid, polysaccharide, protein, lipoprotein or glycoprotein.

[0104] A “complementarity determining region” or “CDR” is a hypervariable region of the antigen-binding region of an antibody. The CDRs are interspersed between regions that are more conserved, termed framework regions (FRs). The antigen-binding region of an antibody may thus comprise one or more CDRs and FRs, usually in each variable domain three CDRs and four FRs arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4.

[0105] The terms “antigenic determinant” and “epitope”, which may also be used interchangeably herein. have the meanings given to it in paragraph l) on page 53 of WO 08 / 020079. In particular, the term “epitope” may refer to a determinant capable of specific binding to an antibody. Epitopes may for example be comprised within polypeptides or proteins. Epitopes may be continuous or discontinuous, wherein a discontinuous epitope is a conformational epitope on an antigen which is formed from at least two separate regions in the primary sequence of the protein, nucleic acid or polysaccharide.

[0106] As further described in paragraph m) on page 53 of WO 08 / 020079, an amino acid sequence (such as a Nanobody, an antibody, a polypeptide of the invention, or generally an antigen binding protein or polypeptide or a fragment thereof) that can (specifically) bind to, that has affinity for and / or that has specificity for a specific antigenic determinant, epitope, antigen or protein (or for at least one part, fragment or epitope thereof) is said to be “against” or “directed against” said antigenic determinant, epitope, antigen or protein.

[0107] The term “specificity” has the meaning given to it in paragraph n) on pages 53-56 of WO 08 / 020079; and as mentioned therein refers to the number of different types of antigens or antigenic determinants to which a particular antigen-binding molecule or antigen-binding protein (such as a Nanobody or a polypeptide of the invention) molecule can bind. The specificity of anantigen-binding protein can be determined based on affinity and / or avidity, as described on pages 53- 56 of WO 08 / 020079 (incorporated herein by reference), which also describes some preferred techniques for measuring binding between an antigen-binding molecule (such as a Nanobody or polypeptide of the invention) and the pertinent antigen. Typically, antigen-binding proteins (such as the amino acid sequences, Nanobodies and / or polypeptides of the invention) will bind to their antigen with a dissociation constant (KD) of 10-5to 10-12moles / liter or less, and preferably 10-7to 10-12moles / liter or less and more preferably 10-8to 10-12moles / liter (i.e. with an association constant (KA) of 105to 1012liter / moles or more, and preferably 107to 1012liter / moles or more and more preferably 108to 1012liter / moles). Any KDvalue greater than 104mol / liter (or any KAvalue lower than 104M-1) liters / mol is generally considered to indicate non-specific binding. Preferably, a monovalent immunoglobulin sequence of the invention will bind to the desired antigen with an affinity less than 500 nM, preferably less than 200 nM, more preferably less than 10 nM, such as less than 500 pM. Specific binding of an antigen-binding protein to an antigen or antigenic determinant can be determined in any suitable manner known per se, including, for example, Scatchard analysis and / or competitive binding assays, such as radioimmunoassays (RIA), enzyme immunoassays (EIA) and sandwich competition assays, and the different variants thereof known per se in the art; as well as the other techniques mentioned herein.

[0108] As will be clear to the skilled person, and as described on pages 53-56 of WO 08 / 020079, the dissociation constant may be the actual or apparent dissociation constant. Methods for determining the dissociation constant will be clear to the skilled person, and for example include the techniques mentioned on pages 53-56 of WO 08 / 020079.

[0109] As used herein, the term “affinity” refers to the strength of binding between receptors and their ligands, for example between an antibody and its antigen. The affinity of an antibody can be defined in terms of the dissociation constant, KD, which is an equilibrium constant that measures the propensity of a molecular complex to separate (dissociate) reversibly into the molecules forming the complex. In one aspect, KDis defined as the ratio koff / kon, where koffand konare the rate constants for association and dissociation of the molecular complex. Preferably affinity is determined by calculating the dissociation constant KD based on IC50 values. Thus, the affinity is measured as an apparent affinity.

[0110] The term “residues,” as used herein, generally refers to single monomers collectively making one polymer. More specifically, the monomers combined in making the single-domain antibodies provided herein, consist of amino acids making up a polypeptide or protein.

[0111] The term “linker,” as used herein, refers to a molecular moiety used to covalently bind two molecules to one another. The linker may be of varying length and structure and may comprise different anchoring groups. In one embodiment, the anchoring group may be selected from the group consisting of amine, carboxylic acid, acid chloride, N-hydroxysuccinimide ester, maleimide, thiol or a polypeptide.

[0112] The term "treatment,” as used herein, refers to any process, action, application, therapy, or the like, wherein a subject, including a human being, is subject to medical aid with the object of improving the animal's condition, directly or indirectly. Thus, a treatment may involve curative treatment, ameliorating treatment and / or prophylactic treatment, where prophylactic treatment can result in complete prevention of a clinical and / or physiological condition or reduce the severity, such as reducing the number of and severity of any symptom associated with the clinical and / or physiological condition.

[0113] For the purposes of comparing two or more nucleotide sequences, the percentage of “sequence identity” between a first nucleotide sequence and a second nucleotide sequence may be calculated or determined as described in paragraph c) on page 49 of WO 08 / 020079 (incorporated herein by reference), such as by dividing [the number of nucleotides in the first nucleotide sequence that are identical to the nucleotides at the corresponding positions in the second nucleotide sequence] by [the total number of nucleotides in the first nucleotide sequence] and multiplying by [100%], in which each deletion, insertion, substitution or addition of a nucleotide in the second nucleotide sequence - compared to the first nucleotide sequence - is considered as a difference at a single nucleotide (position); or using a suitable computer algorithm or technique, again as described in paragraph c) on pages 49 of WO 08 / 020079 (incorporated herein by reference).

[0114] For the purposes of comparing two or more amino acid sequences, the percentage of “sequence identity” between a first amino acid sequence and a second amino acid sequence (also referred to herein as “amino acid identity”) may be calculated or determined as described in paragraph f) on pages 49 and 50 of WO 08 / 020079 (incorporated herein by reference), such as by dividing [the number of amino acid residues in the first amino acid sequence that are identical to the amino acid residues at the corresponding positions in the second amino acid sequence] by [the total number of amino acid residues in the first amino acid sequence] and multiplying by [100%], in which each deletion, insertion, substitution or addition of an amino acid residue in the second amino acid sequence - compared to the first amino acid sequence - is considered as a difference at a single amino acid residue (position), i.e. as an “amino acid difference” as defined herein; or using a suitable computeralgorithm or technique, again as described in paragraph f) on pages 49 and 50 of WO 08 / 020079 (incorporated herein by reference).

[0115] Also, in determining the degree of sequence identity between two amino acid sequences, the skilled person may take into account so-called “conservative” amino acid substitutions, as described on page 50 of WO 08 / 020079.

[0116] Any amino acid substitutions applied to the polypeptides described herein may also be based on the analysis of the frequencies of amino acid variations between homologous proteins of different species developed by Schulz et al., Principles of Protein Structure, Springer-Verlag, 1978, on the analyses of structure forming potentials developed by Chou and Fasman, Biochemistry 13: 211, 1974 and Adv. Enzymol., 47: 45-149, 1978, and on the analysis of hydrophobicity patterns in proteins developed by Eisenberg et al., Proc. Nad. Acad Sci. USA 81: 140-144, 1984; Kyte & Doolittle; J Molec. Biol.157: 105-132, 1981, and Goldman et al., Ann. Rev. Biophys. Chem.15: 321-353, 1986, all incorporated herein in their entirety by reference. Information on the primary, secondary and tertiary structure of Nanobodies is given in the description herein and in the general background art cited above. Also, for this purpose, the crystal structure of a VHH domain from a llama is for example given by Desmyter et al., Nature Structural Biology, Vol. 3, 9, 803 (1996); Spinelli et al., Natural Structural Biology (1996); 3, 752-757; and Decanniere et al., Structure, Vol.7, 4, 361 (1999). Further information about some of the amino acid residues that in conventional VH domains form the VH / VL interface and potential camelizing substitutions on these positions can be found in the publications cited above.

[0117] Methods for determining amino acid sequence “identity” are known in the art. By way of example, a polypeptide of interest may comprise an amino acid sequence having at least 70%, 80%, 90%, 95%, 97%, 99% or 100% amino acid sequence identity with the amino acid sequence of a reference polypeptide. There are many established algorithms available to align two amino acid sequences. Typically, one sequence acts as a reference sequence, to which test sequences may be compared. The sequence comparison algorithm calculates the percentage sequence identity for the test sequence(s) relative to the reference sequence, based on the designated program parameters. Alignment of amino acid sequences for comparison may be conducted, for example, by computer implemented algorithms (e.g., GAP, BESTFIT, FASTA or TFASTA), or BLAST and BLAST 2.0 algorithms. The BLOSUM62 table shown below is an amino acid substitution matrix derived from about 2,000 local multiple alignments of protein sequence segments, representing highly conserved regions of more than 500 groups of related proteins (Henikoff & Henikoff, Proc. Natl. Acad. Sci. USA89:10915-10919, 1992; incorporated herein by reference). Amino acids are indicated by the standard one-letter codes. The percent identity is calculated as: Total number of identical matches __________________________________________ x 100 [length of the longer sequence plus the number of gaps Introduced into the longer sequence in order to align the two sequences] BLOSUM62 table A R N D C Q E G H I L K M F P S T W Y V A 4 R -1 5 N -2 0 6 D -2 -2 1 6 C 0 -3 -3 -3 9 Q -1 1 0 0 -3 5 E -1 0 0 2 -4 2 5 G 0 -2 0 -1 -3 -2 -2 6 H -2 0 1 -1 -3 0 0 -2 8 I -1 -3 -3 -3 -1 -3 -3 -4 -3 4 L -1 -2 -3 -4 -1 -2 -3 -4 -3 2 4 K -1 2 0 -1 -3 1 1 -2 -1 -3 -2 5 M -1 -1 -2 -3 -1 0 -2 -3 -2 1 2 -1 5 F -2 -3 -3 -3 -2 -3 -3 -3 -1 0 0 -3 0 6 P -1 -2 -2 -1 -3 -1 -1 -2 -2 -3 -3 -1 -2 -4 7 S 1 -1 1 0 -1 0 0 0 -1 -2 -2 0 -1 -2 -1 4 T 0 -1 0 -1 -1 -1 -1 -2 -2 -1 -1 -1 -1 -2 -1 1 5 W -3 -3 -4 -4 -2 -2 -3 -2 -2 -3 -2 -3 -1 1 -4 -3 -211 Y -2 -2 -2 -3 -2 -1 -2 -3 2 -1 -1 -2 -1 3 -3 -2 -2 2 7 V 0 -3 -3 -3 -1 -2 -2 -3 -3 3 1 -2 1 -1 -2 -2 0 -3 -1 4

[0118] Sequence identity may exist over a region of the sequences that is at least e.g.10 amino acid residues in length (e.g., at least 15, 20, 30, 40, 50, 75, 100 amino acid residues in length) – e.g., up to the entire length of the reference sequence. Substantially homologous polypeptides have one or more amino acid substitutions, deletions, or additions. In many embodiments, those changes are of a minor nature, for example, involving only conservative amino acid substitutions. Conservative substitutions are those made by replacing one amino acid with another amino acid within the following groups: Basic: arginine, lysine, histidine; Acidic: glutamic acid, aspartic acid; Polar: glutamine, asparagine; Hydrophobic: leucine, isoleucine, valine; Aromatic: phenylalanine, tryptophan, tyrosine; Small: glycine, alanine, serine, threonine, methionine. Substantially homologous polypeptides also encompass those comprising other substitutions that do not significantly affect the folding or activity of the polypeptide; small deletions, typically of 1 to about 30 amino acids (such as 1-10, or 1-5 amino acids); and small amino- or carboxyl-terminal extensions, such as an amino-terminal methionine residue, a small linker peptide of up to about 20-25 residues, or an affinity tag.

[0119] Amino acid sequences and nucleic acid sequences are said to be “exactly the same” if they have 100% sequence identity (as defined herein) over their entire length.

[0120] When comparing two amino acid sequences, the term “amino acid difference” refers to an insertion, deletion or substitution of a single amino acid residue on a position of the first sequence, compared to the second sequence; it being understood that two amino acid sequences can contain one, two or more such amino acid differences.

[0121] The term “humanization” (and corresponding terms used herein such as "humanized") has its usual meaning in the art and generally refers to replacing one or more amino acid residues in the amino acid sequence of a naturally occurring antibody sequence (and in particular in the framework sequences thereof) that has been derived from an animal (and in particular a mammal) other than a human being with one or more of the amino acid residues that occur at the corresponding position(s) in the amino acid sequence of an antibody sequence that has been derived from a human being. This can be performed in a manner known per se, which will be clear to the skilled person, for example on the basis of the further description herein and the publications on humanization referred to herein. For example and without limitation, for the humanization of VHH and Nanobodies, the tables on pages 79 to 82 mention, for the different positions in the amino acid sequence of a VHH or Nanobody, some of the amino acid residues that are present at the corresponding position in a human VH3 sequence (as well as the so-called “Hallmark residues” that are commonly found in the amino acid sequence of Nanobodies). It should also be noted that, in the practice of the invention, C1q binders of the invention can be generated by first (suitably) introducing, into the sequence of a naturally occurring C1q binder,one or more mutations that reduce the affinity of the C1q binder for C1q (as further described herein) and then (suitably) introducing, into the variant of the naturally occurring C1q binder thus obtained, one or more humanized substitutions; or alternatively C1q binders of the invention can be generated by first (suitably) introducing, into the sequence of a naturally occurring C1q binder, one or more humanizing substitutions, and suitably) introducing, into the sequence of a said humanized variant, one or more mutations that reduce the affinity of the C1q binder for C1q (as further described herein); or any suitable combination of the foregoing. Is should also be noted that, in particular with respect to any antibody or antibody-derived sequence, the term “naturally occurring” generally relates to a sequence that is or can be generated from the immune repertoire of a suitable species of animal (and in particular a suitable species of mammal, such as – in the case of a naturally occurring VHH sequence -a a species of Camelid (including transgenic animals from other mammalian species other than Camelids whose immune repertoire has been “camelized”). Methods of generating such naturally occurring (antibody) sequences will be clear to the skilled person, and for example include screening, with the antigen of interest, a suitable immune library (in particular an such immune library that has been obtained from an animal that has been suitably immunized with the antigen of interest) or for example screening, with the antigen of interest, of an immune library that has been obtained from an animal (and in particular a species of mammal, such as a species of Camelid), optionally followed by affinity maturation or similar techniques.

[0122] When a nucleotide sequence or amino acid sequence is said to “comprise” another nucleotide sequence or amino acid sequence, respectively, or to “essentially consist of” another nucleotide sequence or amino acid sequence, this has the meaning given in paragraph i) on pages 51- 52 of WO 08 / 020079.

[0123] The term “in essentially isolated form” has the meaning given to it in paragraph j) on pages 52 and 53 of WO 08 / 020079.

[0124] The terms “domain” and “binding domain” have the meanings given to it in paragraph k) on page 53 of WO 08 / 020079.

[0125] The half-life of an amino acid sequence, compound or polypeptide of the invention can generally be defined as described in paragraph o) on page 57 of WO 08 / 020079 and as mentioned therein refers to the time taken for the serum concentration of the amino acid sequence, compound or polypeptide to be reduced by 50%, in vivo, for example due to degradation of the sequence or compound and / or clearance or sequestration of the sequence or compound by natural mechanisms. The in vivo half-life of an amino acid sequence, compound or polypeptide of the invention can be determined in any manner known per se, such as by pharmacokinetic analysis. Suitable techniqueswill be clear to the person skilled in the art, and may for example generally be as described in paragraph o) on page 57 of WO 08 / 020079. As also mentioned in paragraph o) on page 57 of WO 08 / 020079, the half-life can be expressed using parameters such as the t1 / 2-alpha, t1 / 2-beta and the area under the curve (AUC). Reference is for example made to the Experimental Part below, as well as to the standard handbooks, such as Kenneth, A et al: Chemical Stability of Pharmaceuticals: A Handbook for Pharmacists and Peters et al, Pharmacokinete analysis: A Practical Approach (1996). Reference is also made to "Pharmacokinetics", M Gibaldi & D Perron, published by Marcel Dekker, 2nd Rev. edition (1982). The terms “increase in half-life” or “increased half-life” as also as defined in paragraph o) on page 57 of WO 08 / 020079 and in particular refer to an increase in the t1 / 2-beta, either with or without an increase in the t1 / 2-alpha and / or the AUC or both.

[0126] In the context of the present invention, “modulating” or “to modulate” generally means either reducing or inhibiting the activity of, or alternatively increasing the activity of, a target or antigen, as measured using a suitable in vitro, cellular or in vivo assay. In particular, “modulating” or “to modulate” may mean either reducing or inhibiting the activity of, or alternatively increasing a (relevant or intended) biological activity of, a target or antigen, as measured using a suitable in vitro, cellular or in vivo assay (which will usually depend on the target or antigen involved), by at least 1%, preferably at least 5%, such as at least 10% or at least 25%, for example by at least 50%, at least 60%, at least 70%, at least 80%, or 90% or more, compared to activity of the target or antigen in the same assay under the same conditions but without the presence of the construct of the invention.

[0127] As will be clear to the skilled person, “modulating” may also involve effecting a change (which may either be an increase or a decrease) in affinity, avidity, specificity and / or selectivity of a target or antigen for one or more of its ligands, binding partners, partners for association into a homomultimeric or heteromultimeric form, or substrates; and / or effecting a change (which may either be an increase or a decrease) in the sensitivity of the target or antigen for one or more conditions in the medium or surroundings in which the target or antigen is present (such as pH, ion strength, the presence of co-factors, etc.), compared to the same conditions but without the presence of the construct of the invention. As will be clear to the skilled person, this may again be determined in any suitable manner and / or using any suitable assay known per se, depending on the target or antigen involved.

[0128] “Modulating” may also mean effecting a change (i.e. an activity as an agonist, as an antagonist or as a reverse agonist, respectively, depending on the target or antigen and the desired biological or physiological effect) with respect to one or more biological or physiological mechanisms, effects, responses, functions, pathways or activities in which the target or antigen (or in which its substrate(s), ligand(s) or pathway(s) are involved, such as its signalling pathway or metabolic pathwayand their associated biological or physiological effects) is involved. Again, as will be clear to the skilled person, such an action as an agonist or an antagonist may be determined in any suitable manner and / or using any suitable (in vitro and usually cellular or in assay) assay known per se, depending on the target or antigen involved. In particular, an action as an agonist or antagonist may be such that an intended biological or physiological activity is increased or decreased, respectively, by at least 1%, preferably at least 5%, such as at least 10% or at least 25%, for example by at least 50%, at least 60%, at least 70%, at least 80%, or 90% or more, compared to the biological or physiological activity in the same assay under the same conditions but without the presence of the construct of the invention.

[0129] Modulating may for example also involve allosteric modulation of the target or antigen; and / or reducing or inhibiting the binding of the target or antigen to one of its substrates or ligands and / or competing with a natural ligand, substrate for binding to the target or antigen. Modulating may also involve activating the target or antigen or the mechanism or pathway in which it is involved. Modulating may for example also involve effecting a change in respect of the folding or confirmation of the target or antigen, or in respect of the ability of the target or antigen to fold, to change its confirmation (for example, upon binding of a ligand), to associate with other (sub)units, or to disassociate. Modulating may for example also involve effecting a change in the ability of the target or antigen to transport other compounds or to serve as a channel for other compounds (such as ions). Modulating may be reversible or irreversible, but for pharmaceutical and pharmacological purposes will usually be in a reversible manner.

[0130] In respect of a target or antigen, the term “interaction site” on the target or antigen means a site, epitope, antigenic determinant, part, domain or stretch of amino acid residues on the target or antigen that is a site for binding to a ligand, receptor or other binding partner, a catalytic site, a cleavage site, a site for allosteric interaction, a site involved in multimerisation (such as homomerization or heterodimerization) of the target or antigen; or any other site, epitope, antigenic determinant, part, domain or stretch of amino acid residues on the target or antigen that is involved in a biological action or mechanism of the target or antigen. More generally, an “interaction site” can be any site, epitope, antigenic determinant, part, domain or stretch of amino acid residues on the target or antigen to which an amino acid sequence or polypeptide of the invention can bind such that the target or antigen (and / or any pathway, interaction, signalling, biological mechanism or biological effect in which the target or antigen is involved) is modulated (as defined herein).

[0131] An amino acid sequence or polypeptide is said to be “specific for” a first target or antigen compared to a second target or antigen when is binds to the first antigen with an affinity (as described above, and suitably expressed as a KDvalue, KAvalue, Koffrate and / or Konrate) that is atleast 10 times, such as at least 100 times, and preferably at least 1000 times, and up to 10.000 times or more better than the affinity with which said amino acid sequence or polypeptide binds to the second target or polypeptide. For example, the first antigen may bind to the target or antigen with a KDvalue that is at least 10 times less, such as at least 100 times less, and preferably at least 1000 times less, such as 10.000 times less or even less than that, than the KD with which said amino acid sequence or polypeptide binds to the second target or polypeptide. Preferably, when an amino acid sequence or polypeptide is “specific for” a first target or antigen compared to a second target or antigen, it is directed against (as defined herein) said first target or antigen, but not directed against said second target or antigen.

[0003] The terms “cross-block”, “cross-blocked” and “cross-blocking” are used interchangeably herein to mean the ability of an amino acid sequence or other binding agents (such as a polypeptide of the invention) to interfere with the binding of other amino acid sequences or binding agents of the invention to a given target. The extend to which an amino acid sequence or other binding agents of the invention is able to interfere with the binding of another to [target], and therefore whether it can be said to cross-block according to the invention, can be determined using competition binding assays. One particularly suitable quantitative assay uses a Biacore machine which can measure the extent of interactions using surface plasmon resonance technology. Another suitable quantitative cross-blocking assay uses an ELISA-based approach to measure competition between amino acid sequence or another binding agents in terms of their binding to the target. Also, as will be clear to the skilled person, two binding domains, binding units or antibodies that are directed against the same binding site or epitope on an antigen will compete for binding to said binding site or epitope in a (suitable) competitive binding assay and / or able to cross-block each other’s binding to said binding site or epitope.

[0132] As further described herein, the total number of amino acid residues in a Nanobody can be in the region of 110-120, is preferably 112-115, and is most preferably 113. It should however be noted that parts, fragments, analogs or derivatives (as further described herein) of a Nanobody are not particularly limited as to their length and / or size, as long as such parts, fragments, analogs or derivatives meet the further requirements outlined herein and are also preferably suitable for the purposes described herein;

[0133] The amino acid residues of a Nanobody are numbered according to the general numbering for VH domains given by Kabat et al. ("Sequence of proteins of immunological interest", US Public Health Services, NIH Bethesda, MD, Publication No.91), as applied to VHH domains from Camelids in the article of Riechmann and Muyldermans, Journal of Immunological Methods 2311999 25–38 (see for example Figure 2 of said article or referred to herein. Reference is also made to thefollowing website: http: / / www.bioinf.org.uk / abs / info.html#kabatnum). According to this numbering, FRl of a Nanobody comprises the amino acid residues at positions 1-30, CDRl of a Nanobody comprises the amino acid residues at positions 31-35, FR2 of a Nanobody comprises the amino acids at positions 36-49, CDR2 of a Nanobody comprises the amino acid residues at positions 50-65, FR3 of a Nanobody comprises the amino acid residues at positions 66-94, CDR3 of a Nanobody comprises the amino acid residues at positions 95-102, and FR4 of a Nanobody comprises the amino acid residues at positions 103-113. [In this respect, it should be noted that - as is well known in the art for VH domains and for VHH domains - the total number of amino acid residues in each of the CDR' s may vary and may not correspond to the total number of amino acid residues indicated by the Kabat numbering (that is, one or more positions according to the Kabat numbering may not be occupied in the actual sequence, or the actual sequence may contain more amino acid residues than the number allowed for by the Kabat numbering). This means that, generally, the numbering according to Kabat may or may not correspond to the actual numbering of the amino acid residues in the actual sequence. Generally, however, it can be said that, according to the numbering of Kabat and irrespective of the number of amino acid residues in the CDR' s, position 1 according to the Kabat numbering corresponds to the start of FRl and vice versa, position 36 according to the Kabat numbering corresponds to the start of FR2 and vice versa, position 66 according to the Kabat numbering corresponds to the start of FR3 and vice versa, and position 103 according to the Kabat numbering corresponds to the start of FR4 and vice versa.]. Alternative methods for numbering the amino acid residues of VH domains, which methods can also be applied in an analogous manner to VHH domains from Camelids and to Nanobodies, are the method described by Chothia et al. (Nature 342, 877-883 (1989)), the so-called "AbM definition" and the so-called "contact definition". However, in the present description, claims and figures, the numbering according to Kabat as applied to VHH domains by Riechmann and Muyldermans will be followed, unless indicated otherwise;

[0134] It should be noted that some of the mutations disclosed herein are (also) described with reference to their position in the sequence of the preferred C1 binder in which they can be made (in particular, in the sequence of Nb75 or Nb78, respectively. If so, these mutations may also be mentioned herein with reference to their position in the sequence of Nb75 or Nb78, respectively, rather than according to the Kabat numbering. For the sake of reference, Table E below is a transposition Table listing: (i) the amino acid residues in the CDRs of Nb75 and Nb78, respectively (in bold / double underline; see column II, V and VII for Nb78 and column III, VI and IX for Nb 75, respectively); (ii) the position according to the Kabat numbering (columns I, IV and VII); and (iii) for CDR3, the numbering used when reference is made to the sequences for Nb78 and 78. Also forthe sake of reference, Table D mentions some of the amino acid residues that are present in the framework regions that flank the CDRs. Thus, by means of example and as will be clear to the skilled person from Table D, the M33A mutation mentioned herein for CDR1 of Nb78 will be at position 52 according to Kabat; the T53G mutation mentioned herein for CDR2 of Nb75 will be at position 52 according to Kabat; the T102A mutation mentioned herein for CDR3 of Nb78 will be at position 96 according to Kabat; and the S103A mutation mentioned herein for CDR3 of Nb78 will be at position 97 according to Kabat. Also, based on the disclosure herein with respect to mutation(s) for Nb75 and Nb78, the skilled person will be able to make and test similar or equivalent mutations in other C1q binders, for example in some of the other C1q binders mentioned herein.

[0135] With reference to a C1q binder, the wording “with reduced affinity for C1q” is generally used herein to indicate that said C1q binder has a binding affinity to the C1q complement factor of from about 10 nanoMolar (nM) to about 2 microMolar (μM), as determined by biolayer interferometry, in particular of about 0.1 μM to about 2 μM, as determined by biolayer interferometry. In particular, such a C1q binder may bind to the C1q complement factor with a KD from about 10 nM to about 1.5 μM, from about 50 nM to about 1.4 μM, from about 100 nM to about 1.3 μM, from about 150 nM to about 1.2 μM or from about 200 nM to about 1 μM. As described in more detail in in the co-pending non-prepublished International application entitled “Engineered complement engaging polypeptides” referred to herein, a C1q binder “with reduced affinity for C1q” may be a variant of a naturally occurring (i.e. “wild-type”) C1q binder that comprises one or more modifications relative to said wild-type C1q binder, with said one or more modifications resulting in reduced binding affinity to a C1q complement factor as compared to a binding affinity of the corresponding wild-type C1q binder. For example and without limitation, as also described in said co-pending International application, in one particular aspect, such a C1q binder “with reduced affinity for C1q” may be a variant of Nb75 with reduced affinity for C1q compared to Nb75 or a variant of Nb78 with reduced affinity for C1q compared to Nb78 (reference is again made to the further description herein). Also, in the present description and claims, the term: “affinity for C1q” in particular refers to affinity for the globular head of C1q, and more in particular affinity for the globular head of C1q as determined by the method set out in Example 1.

[0136] The term “C1q binder” (which term is used interchangeably herein with the wording “complement factor-engaging domain that binds to C1q”) refers to a complement factor-engaging domain that binds to C1q, which complement factor-engaging domain is as further described herein. As further described herein, according to one preferred but non-limiting aspect, such a C1q binder is a C1q binder “with reduced affinity for C1q” as further described in the co-pending non-prepublishedInternational application entitled “Engineered complement engaging polypeptides” referred to herein. As described herein and in said co-pending International application, according to a particular aspect of the invention, a C1q binder that is used in the invention is preferably a single domain antibody (also sometimes referred to as an immunoglobulin single variable domain or “ISVD”), and more preferably a Nanobody (including VHHs obtained from a Camelid as well as for example Nanobodies from synthetic or semi-synthetic origin).

[0137] Unless explicitly indicated otherwise herein, when a C1q binder is said to be “linked or fused to” an antibody heavy chain or light chain, it may be linked or fused to such heavy or light chain in any suitable manner (i.e. at a position and in a manner that essentially does not interfere with the desired action(s) of said C1q binder and heavy or light chain). In particular, and unless explicitly indicated otherwise herein, when a C1q binder is said to be “linked or fused to” an antibody heavy chain or light chain, it may be linked or fused to the N-terminus or to the C-terminus of such heavy chain or light chain. According to a specific but non-limiting aspect, examples of which are given in the Experimental Part below, when a C1q binder is said to be “linked or fused to” an antibody heavy chain, it may in practice in particular be linked or fused to the N-terminus of such heavy chain; and when a C1q binder is said to be “linked or fused to” an antibody light heavy chain, it may in practice in particular be linked or fused to the C-terminus of such light chain.

[0138] Also, when two C1q binders are said to be “linked or fused to” an “antibody of the invention” (as described herein), each such C1q binder may be the same or different, but they are preferably the same. Furthermore, when two C1q binders are said to be linked or fused to an “antibody of the invention” (as described herein), each of said C1q binders may, independently from the other, be linked or fused (as described herein) to the heavy chain or to the light chain; but in the practice of the invention, and preferably, either both C1q binders will be linked or fused to the two heavy chains (with one C1q binder being linked or fused to one of the heavy chains and the other being linked or fused to the other heavy chain) or alternatively both C1q binders will be linked or fused to the two light chains (with one C1q binder being linked or fused to one of the light chains and the other being linked or fused to the other light chain). Also, in the practice of the invention, and preferably, when one of the C1q binders is linked or fused to the C-terminus of a heavy or light chain, respectively, that is present in an antibody of the invention, the other C1q binder will be linked or fused to the C-terminus of other heavy or light chain, respectively, that is present in said antibody of the invention; and conversely; when one of the C1q binders is linked or fused to the N-terminus of a heavy or light chain, respectively, that is present in an antibody of the invention, the other C1q binder will be linked or fused to the N-terminus of other heavy or light chain, respectively, that is present in said antibody ofthe invention. According to a specific but non-limiting aspect, examples of which are given in the Experimental Part below, when an antibody of the invention contains two C1q binders that are each linked or fused to one of the heavy chains that are present in said antibody of the invention, one of said C1q binders may in particular be linked or fused to the N-terminus of one of the heavy chains, and the other C1q binder may be linked or fused to the N-terminus of the other heavy chain; or alternatively, when an antibody of the invention contains two C1q binders that are each linked or fused to one of the light chains that are present in said antibody of the invention, one of said C1q binders may in particular be linked or fused to the C-terminus of one of the light chains, and the other C1q binder may be linked or fused to the C-terminus of the other light chain.

[0139] The term “antibody of the invention” generally refers to an antibody comprising two antibody heavy chains (with each heavy chain comprising a VH domain, a CH1 domain and an FC portion, with the Fc portion being comprised of a CH2 domain and a CH3 domain) and two antibody light chains (with each light chain comprising a VLand a CLdomain), which antibody suitably comprises at least two (and preferably two) C1q binders as further described herein (and preferably two C1q binders having with reduced affinity for C1q, as further described herein) that are each “linked or fused to” (as described herein) said antibody of the invention.

[0140] The Figures, Sequence Listing and the Experimental Part / Examples are only given to further illustrate the invention and should not be interpreted or construed as limiting the scope of the invention and / or of the appended claims in any way, unless explicitly indicated otherwise herein.

[0141] For a general description of heavy chain antibodies and the variable domains thereof, reference is inter alia made to the publications cited herein, as well as to the publications mentioned on page 59 of WO 08 / 020079 and to the list of references mentioned on pages 41-43 of the International application WO 06 / 040153, which publications and references are incorporated herein by reference. For example, pages 72 to 82 of WO 08 / 020079 give a detailed description of some of the characteristics (including the so-called “Hallmark residues”) that are commonly found in the amino acid sequence of Nanobodies.

[0142] In accordance with the terminology used in the art (see the above references), the variable domains present in naturally occurring heavy chain antibodies will also be referred to as “VHH domains”, in order to distinguish them from the heavy chain variable domains that are present in conventional 4-chain antibodies (which will be referred to hereinbelow as “VHdomains”) and from the light chain variable domains that are present in conventional 4-chain antibodies (which will be referred to hereinbelow as “VLdomains”).

[0143] As mentioned in the publications referred to above, VHH domains have a number of unique structural characteristics and functional properties which make isolated VHH domains (as well as Nanobodies based thereon, which share these structural characteristics and functional properties with the naturally occurring VHH domains) and proteins containing the same highly advantageous for use as functional antigen-binding domains or proteins. In particular, and without being limited thereto, VHHdomains (which have been “designed” by nature to functionally bind to an antigen without the presence of, and without any interaction with, a light chain variable domain) and Nanobodies can function as a single, relatively small, functional antigen-binding structural unit, domain or protein. This distinguishes the VHHdomains from the VHand VLdomains of conventional 4-chain antibodies, which by themselves are generally not suited for practical application as single antigen-binding proteins or domains, but need to be combined in some form or another to provide a functional antigen- binding unit (as in for example conventional antibody fragments such as Fab fragments; in ScFv’s fragments, which consist of a VHdomain covalently linked to a VLdomain). Because of these unique properties, the use of VHH domains and Nanobodies as single antigen-binding proteins or as antigen-binding domains (i.e. as part of a larger protein or polypeptide) offers a number of significant advantages over the use of conventional VHand VLdomains, scFv’s or conventional antibody fragments (such as Fab- or F(ab’)2-fragments), including the advantages that are listed on pages 60 and 61 of WO 08 / 020079. Overview

[0144] Briefly, provided herein are polypeptide constructs that engage a target cell and a target associated with the complement system, e.g., C1q complement factor. The polypeptide constructs are engineered to engage one or more complement factors (such as C1q) and a target of interest (such as a target implicated in a disease) for use in the treatment of a disease. By engaging with the complement factor and the target associated with the disease or condition, the construct is able to recruit the complement system to the site of the target associated with the disease or condition, thus inducing a targeted immune response at the site of the target. The polypeptide constructs of the present disclosure utilize single domain antibodies. Without wishing to be bound by theory, polypeptide constructs with single domain antibodies have greater flexibility, and thus more robust engagement of complement and the target associated with the disease or condition, as compared to bispecific antibodies that utilize full length antibodies.

[0145] Provided herein are: (1) polypeptide constructs comprising a first complement factor- engaging domain, an antigen-binding moiety that binds to a target protein, and a second complementfactor-engaging domain which are directly or indirectly linked; (2) polypeptide constructs comprising a first complement factor-engaging domain, an antigen-binding fragment (Fab) that binds to a target protein, and a second complement factor-engaging domain which are directly or indirectly linked; (3) polypeptide constructs comprising a first C1q complement factor-engaging domain, an antigen- binding domain comprising a crystallized fragment (Fc) that binds to a target protein, and a second complement factor-engaging domain which are directly or indirectly linked; (4) polypeptide constructs comprising a first C1q complement factor-engaging domain, an IgG region that comprises a light chain and a heavy chain, wherein the IgG region comprises an antigen binding fragment (Fab) the binds to a target protein, and a second complement factor-engaging domain which are directly or indirectly linked; (5) polypeptide constructs comprising a first complement factor-engaging domain that binds to C1q, an antigen-binding moiety that binds to a target protein, and a second complement factor- engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety; (6) polypeptide constructs comprising a first complement factor-engaging domain, an antigen-binding moiety that binds to a target protein, and a second complement factor-engaging domain, wherein the first complement factor- engaging domain and the second complement factor-engaging domain are linked to the antigen- binding moiety, and wherein the first complement factor-engaging domain comprises a single variable domain of a heavy chain antibody (VHH domain); (7) polypeptide constructs comprising a first complement factor-engaging domain, an antigen-binding moiety that binds to or modulates a cluster of differentiation 38 (CD38), and a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety, and wherein the antigen-binding moiety is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen- binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof; (8) polypeptide constructs comprising a first complement factor-engaging domain, an antigen-binding fragment that binds to or modulates to an inflammation marker, and a second complement factor-engaging domain, wherein the first complement factor- engaging domain and the second complement factor-engaging domain are linked to the antigen- binding moiety, and wherein the antigen-binding moiety that binds to the inflammation marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variablefragment, a minibody, an antibody, and any combination thereof; (9) polypeptide constructs comprising a first complement factor-engaging domain, an antigen-binding fragment that binds to or modulates to an autoimmune marker, and a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety, and wherein the antigen-binding moiety that binds to the inflammation marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof; (10) compositions comprising any one or more of these polypeptide constructs; (11) pharmaceutical compositions comprising any one or more of these polypeptide constructs; (12) methods of treating a disease involving the administration of any one or more of these polypeptide constructs; (13) method of reducing side-effects associated with antibody-based therapy involving the administration of one or more of these polypeptide constructs; (14) compositions for use in treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, the composition comprising a polypeptide peptide that comprises a complement factor-engaging domain that binds to human C1q complement factor with a binding affinity of about 1 μM, as determined by biolayer interferometry, and an antigen-binding moiety that binds to the cancer-specific marker expressed on the cancer cell, wherein the polypeptide construct treats the cancer in the subject when administered to the subject; (15) a method of treating cancer characterized by aberrant expression of a cancer-specific marker by a cancer cell in a subject in need thereof, the method comprising administering to the subject a polypeptide peptide that comprises a complement factor-engaging domain that binds to human C1q complement factor with a binding affinity of about 1 μM, as determined by biolayer interferometry, and an antigen-binding moiety that binds to the cancer-specific marker expressed on the cancer cell; wherein the administering is sufficient to treat the cancer in the subject; (16) a method of reducing side-effects associated with an IgG antibody-based therapy comprising administering a polypeptide construct that comprises a first complement factor-engaging domain, an IgG region that comprises a light chain and a heavy chain, wherein the IgG region comprises an antigen binding fragment (Fab) the binds to a target protein, and a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the IgG region that binds CD38, wherein the administering results in reduction of one or more side effects as compared to the administering a comparable amount of the IgG antibody-based therapy.

[0146] Accordingly, the polypeptide constructs of the present disclosure can be used to treat diseases or conditions such as autoimmune disease, inflammatory disease, or cancer, where the antigen-binding moiety is directed against a target associated with the disease or condition, resulting in superior complement-mediated cancer cell cytotoxicity. Polypeptide constructs comprising C1q complement factor-engaging domain

[0147] The polypeptide constructs as described herein comprise a first complement factor- engaging domain and a second complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain and / or the second complement factor-engaging domain comprises a C1q complement factor-engaging domain. In some cases, the or each C1q complement factor-engaging domain has a sequence at least 70%, 80%, 90%, 95%, 97%, 99% sequence identity to any one of SEQ ID NO: 1 – SEQ ID NO: 16 or SEQ ID NO: 88 (Table 1). In some embodiments, the or each C1q complement factor-engaging domain has about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 97%, about 98%, about 99% sequence identity to any one of SEQ ID NO: 1 – SEQ ID NO: 16 or SEQ ID NO: 88. Table 1: Exemplary C1q complement factor-engaging domains. SEQ ID NO: SEQUENCE 1 QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADTSARAALYSTGYEYDHWGQGTQVTVSS 2 QVQLVETGGGLVQAGGSLRLSCAASGRTFNNDVMAWFRQAPGTEREF VALITAGGGTHYADSVKGRFVISRDNDKNMAYLQMNSLKSEDTAIYYC GADENPPGWPSRWSSAYDYWGQGTQVTVSS 3 QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAAATSARAALYSTGYEYDHWGQGTQVTVSS 4 QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADASARAALYSTGYEYDHWGQGTQVTVSS 5 QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADTSARAALYSTGAEYDHWGQGTQVTVSSQVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADTSARAALYSTGYAYDHWGQGTQVTVSS QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAAATSARAALYSTGAEYDHWGQGTQVTVSS QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAAATSARAALYSTGYAYDHWGQGTQVTVSS QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADASARAALYSTGAEYDHWGQGTQVTVSS QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYQCAADASARAALYSTGYAYDHWGQGTQVTVSS QVQLVESGGGLVQPGGSLRLSCAASGFTLNQYAIGWFRQAPGKEREGV SCISNSDGGLYYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYC ATDPGGPTMYGSRWCDSRLFYSWGQGTQVTVSS QVQLVESGGGLVQAGGSLRLSCAASGRTSSDHITAWFRQAPGKEREFV ASINWSGSRAYYADSDKRRFTISRDNAKNTVSLQTNSLKPEDTAVYYC AVKFADISDAYYHHQTDYDYWGQGTQVTVSS QVQLVETGGGLVQTGGSLRLSCAASGSTDSIAAIIWYRQTPENEREFVA GITSGVNTNYAAPVKGRFTISRDNAKNTVYLQMNSLKPEDTGVYYCKA AVVMGPSTTDYWGQGTQVTVSS QVQLVETGGGVAQAGGSLRLSCAASGFSFDDYAIGWLRQAPGKEREG VSCISAGDGSPQYADSVKGRFTISSDNAKNTVYLQMNSLKPEDTAVYY CAVSRWSNCAWDYYGMDPWGKGTLVTVSS QVQLVESGGGLAQAGGSLRLSCQGSGRTFNNDVLAWFRQAPGKEREY VAMITSGGNPFYADSVKGRFVISRDNDKNTVYLQMNSLKSEDTAIYYC AAENPPGWPSRWSSAYDYWGQGTQVTVSS16 QVQLVESGGGLVQAGGSLRLSCVAYGVASVTTVMGWFROSPGKEREF VAAIGPSGGTHYGDSAKGRFTISRDNAKNTVYLQMNSLKPEDTAVYDC AADLRGGGMWASSGRYEYWGQGTQVTVSS 88 QVQLVESGGGLVQDGDSLRLSCAGSGWTFRDSMYNMGWFRQAPGKE REFVAAISWRGGSTLYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTA VYKCAADTSARAALYSTGYEYDHWGQGTQVTVSS

[0148] As mentioned herein, other C1q complement factor-engaging domains may for example be suitably chosen from the C1q binders listed in Table A that have a reduced affinity for C1q (as described herein). In particular, they may be chosen from the variants of Nb75 in Table A that have a reduced affinity for C1q and the variants of Nb78 in Table A that have a reduced affinity for C1q. For example, as further described herein, they may be chosen from the variants of Nb75 in Table A that have one or more mutations in their CDRs (which mutations are such that they reduce the affinity for C1q, compared to the affinity for C1q of Nb75, as further described herein) or from the variants of Nb78 in Table A that have one or more mutations in their CDRs (which mutations are such that they reduce the affinity for C1q, compared to the affinity for C1q of Nb78, as further described herein). According to one specific but non-limiting aspect, which is as further herein, the C1q complement factor-engaging domain(s) may be chosen from the variants of Nb78 in Table A that have one or more alanine mutations in their CDRs (which alanine mutations are such that they reduce the affinity for C1q, compared to the affinity for C1q of Nb78, as further described herein).

[0149] In some embodiments, the first complement factor-engaging domain and / or second complement factor-engaging domain can have a Y113A amino acid substitution relative to a C1q- engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor-engaging domain can have an E114A amino acid substitution relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor-engaging domain can have a D101A amino acid substitution relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor- engaging domain can have a D101A amino acid substitution and a Y113A amino acid substitution, relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor- engaging domain can have a T102A amino acid substitution and a Y113A amino acid substitution,relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor- engaging domain can have a D101A amino acid substitution and a E114A amino acid substitution, relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1. In some embodiments, the first complement factor-engaging domain and / or second complement factor- engaging domain can have a T102A amino acid substitution and an E114A amino acid substitution, relative to a C1q-engaging polypeptide having an amino acid sequence of SEQ ID NO: 1.

[0150] In some embodiments, the first complement factor-engaging domain and / or the second complement factor-engaging domain can bind C1q with high affinity. For example, a highaffinity binding can comprise a KD of 1×10 7 M or less. In other embodiments, the or each C1qcomplement factor-engaging domain can bind C1q with low affinity. For example, a low affinitybinding can comprise a KD of 1×10 6 M or more.

[0151] The polypeptide constructs as disclosed herein can directly or indirectly bind to a C1q complement factor. A non-limiting example of a C1q complement factor recognized by polypeptide constructs of the present disclosure is human C1q, including the three polypeptide chains A, B, and C:

[0152] C1q, chain A (Homo sapiens), Accession No. Protein Data Base: NP_057075.1; GenBank No.: NM_015991: gi|7705753|ref|NP_057075.1| complement C1q subcomponent subunit A precursor [Homo sapiens] MEGPRGWLVLCVLAISLASMVTEDLCRAPDGKKGEAGRPGRRGRPGLKGEQGE PGAPGIRTGIQGLKGDQGEPGPSGNPGKVGYPGPSGPLGARGIPGIKGTKGSP GNIKDQPRPAFSAIRRNPPMGGNVVIFDTVITNQEEPYQNHSGRFVCTVPGYY YFTFQVLSQWEICLSIVSSSRGQVRRSLGFCDTTNKGLFQVVSGGMVLQLQQG DQVWVEKDPKKGHIYQGSEADSVFSGFLIFPSA (SEQ ID NO: 17)

[0153] C1q, chain A (Homo sapiens), PDB: 6FCZ QPRPAFSAIRRNPPMGGNVVIFDTVITNQEEPYQNHSGRFVCTVPGYYYFTFQ VLSQWEICLSIVSSSRGQVRRSLGFCDTTNKGLFQVVSGGMVLQLQQGDQVWV EKDPKKGHIYQGSEADSVFSGFLIFPS (SEQ ID NO: 18)

[0154] C1q, chain B (Homo sapiens), Accession No. Protein Data Base: NP_000482.3; GenBank No.: NM_000491.3: >gi|87298828|ref|NP_000482.3| complement C1q subcomponent subunit B precursor [Homo sapiens] MMMKIPWGSIPVLMLLLLLGLIDISQAQLSCTGPPAIPGIPGIPGTPGPDGQPG TPGIKGEKGLPGLAGDHGEFGEKGDPGIPGNPGKVGPKGPMGPKGGPGAPGAPGPKGESGDYKATQKIAFSATRTINVPLRRDQTIREDHVITNMNNNYEPRSGKFTC KVPGLYYFTYHASSRGNLCVNLMRGRERAQKVVTFCDYAYNTFQVTTGGMVLKL EQGENVFLQATDKNSLLGMEGANSIFSGFLLFPDMEA (SEQ ID NO: 19)

[0155] C1q, chain B (Homo sapiens), PDB: 6FCZ TQKIAFSATRTINVPLRRDQTIRFDHVITNMNNNYEPRSGKFTCKVPGLYYFT YHASSRGNLCVNLMRGRERAQKVVTFCDYAYNTFQVTTGGMVLKLEQGENVFL QATDKNSLLGMEGANSIFSGFLLFPD (SEQ ID NO: 20)

[0156] C1q, chain C (Homo sapiens), Accession No. Protein Data Base: NP_001107573.1; GenBank No.: NM_001114101.1: >gi|166235903|ref|NP_001107573.1| complement C1q subcomponent subunit C precursor [Homo sapiens] MDVGPSSLPHLGLKLLLLLLLLPLRGQANTGCYGIPGMPGLPGAPGKDGYDGL PGPKGEPGIPAIPGIRGPKGQKGEPGLPGHPGKNGPMGPPGMPGVPGPMGIPG EPGEEGRYKQKFQSVFTVTRQTHQPPAPNSLIRFNAVLTNPQGDYDTSTGKFT CKVPGLYYFVYHASHTANLCVLLYRSGVKVVTFCGHTSKTNQVNSGGVLLRLQ VGEEVWLAVNDYYDMVGIQGSDSVFSGFLLFPD (SEQ ID NO: 21)

[0157] C1q, chain C (Homo sapiens), PDB: 6FCZ KFQSVFTVTRQTHQPPAPNSLIRFNAVLTNPQGDYDTSTGKFTCKVPGLYYFV YHASHTANLCVLLYRSGVKVVTFCGHTSKTNQVNSGGVLLRLQVGEEVWLAVN DYYDMVGIQGSDSVFSGFLLFPD (SEQ ID NO: 22)

[0158] Accordingly, a polypeptide construct of the present disclosure may bind to polypeptide chain A, polypeptide chain B, and / or polypeptide chain C of a C1q complement factor. In some embodiments, a polypeptide construct according to the present disclosure binds to polypeptide chain A, polypeptide chain B, and / or polypeptide chain C of human C1q or a homolog thereof, such as mouse, rat, rabbit, monkey, dog, cat, cow, horse, camel, sheep, goat, or pig C1q. In other embodiments, the one or more C1q complement factor-engaging domain cannot bind C1q directly.

[0159] In some embodiments, the polypeptide construct comprises a C1q complement factor- engaging domain. In some embodiments, the or each C1q complement factor-engaging domain comprises a single variable domain of a heavy chain (VHH) antibody. In some embodiments, the VHH domain of the one or more C1q complement factor-engaging domains binds to the C1q complement factor with a KDof about 1 nM to about 10 mM. In some embodiments, the VHH domain of the one or more C1q complement factor-engaging domains binds to the C1q complement factor with a KDof about 1 nM to about 5 mM. In some embodiments, the VHH domain of the one or more C1q complement factor-engaging domains binds to the C1q complement factor with a KD of about 10 nMto about 2 mM. In some embodiments, the VHH domain of the one or more C1q complement factor- engaging domains binds to the C1q complement factor with a KD of about 100 nM to about 1.5 mM. In some embodiments, the VHH domain of the one or more C1q complement factor-engaging domains binds to the C1q complement factor with a KD of about 100 nM, about 150 nM, about 200 nM, about 250 nM, about 300 nM, about 350 nM, about 400 nM,, about 450 nM, about 500 nM, about 550 nM, about 600 nM, about 650 nM, about 700 nM,, about 750 nM, about 800 nM, about 850 nM, about 900 nM, about 950 nM, about 1000 nM, about 1100 nM, about 1200 nM, about 1300 nM, about 1400 nM, or about 1500 nM.

[0160] In other embodiments, the polypeptide constructs comprise a first C1q complement factor-engaging domain. In some embodiments, the first complement factor-engaging domain can bind C1q with high affinity. In some embodiments, the first complement factor-engaging domain can bind C1q with low affinity. In some embodiments, the first complement factor-engaging domain comprises a VHH domain. In some embodiments, the VHH domain of the first complement factor-engaging antibody binds to the C1q complement factor with a KD of about 1 nM to about 10 mM. In some embodiments, the VHH domain of the first complement factor-engaging domain binds to the C1q complement factor with a KDof about 1 nM to about 5 mM. In some embodiments, the VHH domain of the first complement factor-engaging domain binds to the C1q complement factor with a KDof about 10 nM to about 2 mM. In some embodiments, the VHH domain of the first complement factor- engaging domain binds to the C1q complement factor with a KDof about 100 nM to about 1.5 mM. In some embodiments, the VHH domain of the first complement factor-engaging domain binds to the C1q complement factor with a KD of about 100 nM, about 150 nM, about 200 nM, about 250 nM, about 300 nM, about 350 nM, about 400 nM, about 450 nM, about 500 nM, about 550 nM, about 600 nM, about 650 nM, about 700 nM, about 750 nM, about 800 nM, about 850 nM, about 900 nM, about 950 nM, about 1000 nM, about 1100 nM, about 1200 nM, about 1300 nM, about 1400 nM, or about 1500 nM.

[0161] In other embodiments, the polypeptide constructs comprise a second C1q complement factor-engaging domain. In some embodiments, the second complement factor-engaging domain can bind C1q with high affinity. In some embodiments, the second complement factor-engaging domain can bind C1q with low affinity. In some embodiments, the second complement factor-engaging domain comprises a VHH domain. In some embodiments, the VHH domain of the second complement factor-engaging domain binds to the C1q complement factor with a KD of about 1 nM to about 10 mM. In some embodiments, the VHH domain of the second complement factor-engaging domain binds to the C1q complement factor with a KDof about 1 nM to about 5 mM. In some embodiments, the VHHdomain of the second complement factor-engaging domain binds to the C1q complement factor with a KD of about 10 nM to about 2 mM. In some embodiments, the VHH domain of the second complement factor-engaging domain binds to the C1q complement factor with a KDof about 100 nM to about 1.5 mM. In some embodiments, the VHH domain of the second complement factor-engaging domain binds to the C1q complement factor with a KD of about 100 nM, about 150 nM, about 200 nM, about 250 nM, about 300 nM, about 350 nM, about 400 nM,, about 450 nM, about 500 nM, about 550 nM, about 600 nM, about 650 nM, about 700 nM,, about 750 nM, about 800 nM, about 850 nM, about 900 nM, about 950 nM, about 1000 nM, about 1100 nM, about 1200 nM, about 1300 nM, about 1400 nM, or about 1500 nM.

[0162] In some embodiments, the first complement factor-engaging domain and / or the second complement factor-engaging domain is a single domain antibody. In some embodiments, the single domain antibodies provided herein comprise an antigen binding site in a single polypeptide that binds to a C1q complement factor. In some embodiments, the single domain antibody is a nanobody. The single antibodies disclosed herein may, though, in certain embodiment be bispecific or multispecific single domain antibodies as described elsewhere herein, where to single domain antibodies are coupled. Single domain antibodies can also be smaller than Fab fragments (~50 kDa) of an antibody that comprises one light chain and half a heavy chain. For example, the polypeptide constructs comprising the single variable domain of a heavy chain (VHH) antibodies according to the present disclosure can comprise one or more CDRs. In particular, the CDRs may identify the specificity of the antibody. Accordingly, in some cases the polypeptide construct comprises an antigen binding site comprises one or more CDRs. In some embodiments, the polypeptide construct comprises at least 1 CDR. In other embodiments, the polypeptide construct comprises at least 2 CDR. In some embodiments, the polypeptide construct comprises at least 3 CDR. In some embodiments, the polypeptide constructs as disclosed herein comprises 3 CDRs.

[0163] The polypeptide constructs as described herein can comprise a single domain antibody that can be used to recruit and activate the complement cascade to specific targets, and thereby specifically activate an innate immune response at a specific target. Such polypeptide constructs are therefore particularly useful in medicine for use as a medicament, and particularly for use in treatment of a disease. In some embodiments, the polypeptide constructs are capable of specifically binding to an epitope of human complement factor C1q and / or the proteolytic derivatives. In some embodiments, the polypeptide constructs as described herein can directly activate the complement system. In some embodiments, the polypeptide constructs as described herein can activate complement by binding to C1q complement factor. In some embodiments, the polypeptide constructs as disclosed hereincomprise a C1q engaging moiety that can bind directly to C1q. In some embodiments, the C1q engaging moiety that can bind directly to C1q can promote a targeted complement-mediated immunological response. In other embodiments, the polypeptide constructs as described herein can indirectly activate the complement system. In some embodiments, the polypeptide constructs as described herein can activate complement without binding to C1q complement factor. In some embodiments, the polypeptide constructs as disclosed herein comprise a C1q engaging moiety that does not bind directly to C1q. In some embodiments, the C1q engaging moiety that does not bind directly to C1q can promote a targeted complement-mediated immunological response. Polypeptide constructs comprising an antigen-binding moiety

[0164] The polypeptide constructs as described herein comprise an antigen-binding moiety. In some embodiments, the antigen-binding moiety comprises a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding(e.g., Fab, Fab , Fab -SH, F(ab )2) domain, a fragment crystallizable (Fc) domain, a single chainvariable fragment (e.g., scFv), single-chain antibody molecules, a minibody, an antibody, a diabody, or a linear antibody. In some embodiments, the antigen-binding moiety comprises an antibody, an antibody fragment, or antibody mimetic protein. In some embodiments, the antibodvy is a monoclonal antibody, a bispecific antibody, a polyclonal antibody, or an antibody fragment. In some embodiments, the antibody is an immunoglobulin. In some embodiments, the immunoglobulin comprises a heavy chain. In some embodiments, the antigen-binding moiety comprises a heavy chain of type: (IgA), (IgD), (IgE), (IgG), or (IgM), optionally of subtypes 1 (IgG1), 2 (IgG2), 3 (IgG3), 4 (IgG4), 1 (IgA1) and 2 (IgA2). In some embodiments, the immunoglobulin comprises a light chain. Insome embodiments, the antigen-binding moiety comprises a light chain of type kappa ( ) or lambda( ), named based on the amino acid sequence of its constant domain. In some embodiments, theimmunoglobulin comprises two Fab molecules and an Fc domain, linked via an immunoglobulin hinge region.

[0165] In some embodiments, the antigen-binding moiety is a Fab or a portion thereof. In some embodiments, the antigen-binding moiety is on the N-terminus of a light chain of a Fab. In some embodiments, the antigen-binding moiety is on the N-terminus of a heavy chain of a Fab. In some embodiments, the antigen-binding moiety is on the C-terminus of a light chain of a Fab. In some embodiments, the antigen-binding moiety is on the C-terminus of a heavy chain of a Fab.

[0166] The antigen-binding moiety binds to a target protein. In some embodiments, the target protein is on a cell. In some embodiments, the target protein is a protein expressed on the surface of a cell. In some embodiments, the cell is a mammalian cell. In some embodiments, the mammalian cell is a cancer cell, an immune cell, an endothelial cell, an epithelial cell, or a microbial cell. In some embodiments, the cancer cell comprises a breast cancer cell, a carcinoma cell, an ovarian cancer cell, an endometrial cancer cell, a colon cancer cell, a gastric cancer cell, a neurological cancer cell, a skin cancer cell, a lung cancer cell, or a bladder cancer cell. In some embodiments, the cancer cell is a carcinoma cell, a breast cancer cell, an ovarian cancer cell, a gastric cancer cell, or a colon cancer cell. In some embodiments, the cancer cell is a lymphoma cell, a myeloma cell, or a leukemia cell. In some embodiments, the target protein is implicated in a disease. In some embodiments, the disease is an autoimmune disease. In some embodiments, the disease is a cancer. In some embodiments, the disease is an inflammatory disease.

[0167] In some embodiments, the polypeptide constructs comprise an antigen-binding moiety that binds to a cancer-specific marker. In some embodiments, the cancer-specific marker comprises a protein that is dysregulated in several cancer forms. In some embodiments, the cancer-specific marker comprises a protein that is upregulated in several cancer forms. In other embodiments, the cancer- specific marker comprises a protein that is downregulated in several cancer forms. In some embodiments, the target protein is CD19, CD20, CD22, CD30, CD33, CD38, CD52, cMET, EGFR, EpCAM, Erb2, FOLR1, GD3, HER, PSMA, PSMA, or VEGF. In some embodiments, the target protein is EGFR, CD38, CD19, CD20, CD55, CD59, CD7, HER2, EGFR, EpCAM, or FOLR1. In some embodiments, the cancer-specific marker is a tumor marker. As used herein, a tumor marker is anything present in or produced by cancer cells or other cells of the body in response to cancer or certain benign (noncancerous) conditions that provides information about a cancer, such as how aggressive it is, what kind of treatment it may respond to, or whether it is responding to treatment.

[0168] In some embodiments, the polypeptide constructs comprise an antigen-binding moiety that binds to a pathogenic marker. In some embodiments, pathogenic markers comprise a protein that is a marker of bacterial, viral or fungal infections. These include for example the structures making up the membrane of gram-negative bacteria like LPS or conserved proteins and structures in the membrane. Relevant markers could be part of the peptidoglycan cell wall of Gram-positive bacteria like teichoic acid lipoteichoic acid. In some embodiments, the marker for viral infections comprise a surface protein on a viral particle. In some embodiments, the surface protein on the viral particle is a viral glycoprotein. In some embodiments, the viral glycoprotein can include, but is not limited to, Hemagglutinin, neuraminidase, and M2 protein in an influenza virus. In other embodiments, the viralglycoprotein can include gp160, composed of subunits gp120 and gp41, in a human immunodeficiency virus (HIV) or an HIV-1 envelope trimer. In some embodiments, the fungal infections can be targeted via conserved fungal surface antigens.

[0169] In some embodiments, the polypeptide constructs comprise an antigen-binding moiety that binds to an inflammation marker. In some embodiments, the inflammation marker is selected from the group consisting of IL-6, CRP, TNF, IL-10, IL-17, IGN-gamma, eotaxin, IP-10, MCP-1, and MIG. In some embodiments, the polypeptide constructs comprise an antigen-binding moiety that binds to an autoimmune marker. In some embodiments, the autoimmune marker is a target protein is implicated in multiple sclerosis, psoriasis, psoriatic arthritis, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, Sjogren's syndrome, Behcet's disease, ulcerative colitis, or Guillain- Barre syndrome. Linkers

[0170] In some embodiments, the antigen-binding moiety is directly linked to the first complement factor-engaging domain. In some embodiments, the antigen-binding moiety is directly linked to the second complement factor-engaging domain. In some embodiments, the antigen-binding moiety is directly linked to the first complement factor-engaging domain and the second complement factor-engaging domain. In other embodiments, the antigen-binding moiety is indirectly linked to the first complement factor-engaging domain. In some embodiments, the antigen-binding moiety is indirectly linked to or the second complement factor-engaging domain. In some embodiments, the antigen-binding moiety is indirectly linked to the first complement factor-engaging domain and the second complement factor-engaging domain. In some embodiments, the first complement factor- engaging domain and / or the second complement factor-engaging domain is linked to an antigen- binding moiety through a linker sequence, a Fab region, Fc region, or an IgG region of an antibody.

[0171] In some embodiments, the antigen-binding moiety is linked to the first complement factor-engaging domain and / or the second complement factor-engaging domain via a linker sequence. In some embodiments, the antigen-binding moiety is linked to the first complement factor-engaging domain via a first linker sequence and is linked to the second complement factor-engaging domain via a second linker sequence. The first linker sequence and the second linker sequence may be the same or different. In some embodiments, the linker sequence is at least 5 amino acids, at least 10 amino acids, at least 15 amino acids, at least 20 amino acids, at least 25 amino acids, at least 30 amino acids, at least 35 amino acids, at least 40 amino acids, at least 45 amino acids, or at least 50 amino acids. In some embodiments, the linker sequence is about 5 amino acids, about 10 amino acids, about 15 aminoacids, about 20 amino acids, about 25 amino acids, about 30 amino acids, about 35 amino acids, about 40 amino acids, about 45 amino acids, or about 50 amino acids. In some embodiments, the linker sequence is about 15 amino acids. In some embodiments, the linker is 15 amino acids. In some embodiments, the linker sequence is about 20 amino acids. In some embodiments, the linker sequence is 20 amino acids.

[0172] In some embodiments, the linker sequence is a non-immunogenic linker peptide. For example, suitable, non-immunogenic linker peptides are, (G4S)n, (SG4)nor G4(SG4)npeptide linkers, wherein "n" is generally a number between 1 and 10, typically between 2 and 4, in particular 2, e.g., the peptides selected from the group consisting of GGGGS (SEQ ID NO: 23), GGGGSGGGGS (SEQ ID NO: 24), SGGGGSGGGG (SEQ ID NO: 25) and GGGGSGGGGSGGGG (SEQ ID NO: 26), GSPGSSSSGS (SEQ ID NO: 27), (G4S) (SEQ ID NO: 28), (G4S)2 (SEQ ID NO: 29), (G4S)3 (SEQ ID NO: 30), (G4S)4 (SEQ ID NO: 31), GSGSGSGS (SEQ ID NO: 32), GSGSGNGS (SEQ ID NO: 33), GGSGSGSG (SEQ ID NO: 34), GGSGSG (SEQ ID NO: 35), GGSG (SEQ ID NO: 36), GGSGNGSG (SEQ ID NO: 37), GGNGSGSG (SEQ ID NO: 38), GGNGSG (SEQ ID NO: 39), GGGGSGGGGSGGGGS (SEQ ID NO: 40), and GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 41).

[0173] In some embodiments, the first complement factor-engaging domain and / or the second complement factor-engaging domain is linked to an antigen-binding moiety fragment (Fab) region of an antibody. In some embodiments, a Fab region of an antibody is linked to a first complement factor- engaging domain and / or a second complement factor-engaging domain at the N-terminus of the Fab region of the antibody. In some cases, a Fab region of an antibody is linked to a first complement factor-engaging domain and / or a second complement factor-engaging domain at the C-terminus of the Fab region of the antibody. In other embodiments, a Fab region of an antibody is linked to a first complement factor-engaging domain and / or the second complement factor-engaging domain at the N- terminus of the first complement factor-engaging domain and / or the second complement factor- engaging domain. In some embodiments, the Fab region of the antibody is linked to the first complement factor-engaging domain and / or the second complement factor-engaging domain at the C- terminus of first complement factor-engaging domain and / or the second complement factor-engaging domain.

[0174] In some embodiments, the polypeptide constructs comprise an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody selected from the group consisting of: abagovomab, abciximab, abituzumab, abrilumab, actinium Ac-225 lintuzumab, actoxumab, adalimumab, adecatumumab, aducanumab, afelimomab, afutuzumab, alacizumab pegol,alemtuzumab, alirocumab, altumomab pentetate, amatuximab, anatumomab mafenatox, anetumab ravtansine, anifrolumab, anrukinzumab, apolizumab, sevacizumab, arcitumomab, ascrinvacumab, aselizumab, atezolizumab, atinumab, atorolimumab, avelumab, bapineuzumab, basiliximab, bavituximab, bectumomab, begelomab, belimumab, benralizumab, bertilimumab, besilesomab, 177Lu-tetraxetan-tetulomab, bevacizumab, bezlotoxumab, biciromab, bimagrumab, bimekizumab, bivatuzumab mertansine, blinatumomab, blosozumab, bococizumab, brentuximab vedotin, BrevaRex, briakinumab, brodalumab, brolucizumab, brontictuzumab, canakinumab, cantuzumab mertansine, cantuzumab ravtansine, caplacizumab, capromab pendetide, carlumab, catumaxomab, CBR96- doxorubicin immunoconjugate, cedelizumab, certolizumab pegol, cetuximab, citatuzumab bogatox, cixutumumab, clazakizumab, clenoliximab, clivatuzumab tetraxetan, Clone 003 and Clone 024 (see WO2006 / 099875), CM313, . codrituzumab, coltuximab ravtansine, conatumumab, concizumab, cR6261, crenezumab, dacetuzumab, daclizumab, dalotuzumab, dapirolizumab pegol, daratumumab, darleukin, dectrekumab, demcizumab, denintuzumab mafodotin, denosumab, depatuxizumab, depatuxizumab mafodotin, derlotuximab biotin, detumomab, dinutuximab, diridavumab, dorlimomab aritox, drozitumab, duligotumab, dupilumab, durvalumab, dusigitumab, ecromeximab, eculizumab, edobacomab, edrecolomab, efalizumab, efungumab, eldelumab, elgemtumab, elotuzumab, elsilimomab, emactuzumab, emibetuzumab, enavatuzumab, enfortumab vedotin, enlimomab pegol, enoblituzumab, enokizumab, enoticumab, ensituximab, epitumomab cituxetan, epratuzumab, erlizumab, ertumaxomab, etaracizumab, etrolizumab, evinacumab, evolocumab, exbivirumab, fanolesomab, faralimomab, farletuzumab, fasinumab, felvizumab, felzartamab, fezakinumab, FGFR2 Antibody-Drug Conjugate, Fibromun, ficlatuzumab, figitumumab, firivumab, flanvotumab, fletikumab, fontolizumab, foralumab, foravirumab, fresolimumab, fulranumab, futuximab, galiximab, ganitumab, gantenerumab, gavilimomab, gemtuzumab, gevokizumab, girentuximab, glembatumumab vedotin, golimumab, gomiliximab, guselkumab, ibalizumab, ibritumomab tiuxetan, icrucumab, idarucizumab, igovomab, imalumab, imciromab, imgatuzumab, inclacumab, indatuximab ravtansine, indusatumab vedotin, inebilizumab, infliximab, inolimomab, inotuzumab ozogamicin, intetumumab, ipilimumab, iratumumab, isatuximab, istiratumab, itolizumab, ixekizumab, keliximab, labetuzumab, labetuzumab govitecan, lambrolizumab, lampalizumab, lebrikizumab, lemalesomab, lenzilumab, lerdelimumab, leukotuximab, lexatumumab, libivirumab, lifastuzumab vedotin, ligelizumab, lilotomab satetraxetan, lintuzumab, lirilumab, lodelcizumab, lokivetmab, lorvotuzumab mertansine, lucatumumab, lulizumab pegol, lumiliximab, lumretuzumab, mapatumumab, margetuximab, maslimomab, matuzumab, mavrilimumab, mezagitamab, mepolizumab, metelimumab, milatuzumab, milatuzumab-SN-38, minretumomab, mirvetuximab soravtansine, mitazalimab, mitumomab,mogamulizumab, morolimumab, MORO3080, MORO 3087, MORO3088, motavizumab, moxetumomab pasudotox, MU1053, muromonab-CD3, nacolomab tafenatox, namilumab, naptumomab estafenatox, narnatumab, natalizumab, nebacumab, necitumumab, nemolizumab, nerelimomab, nesvacumab, nimotuzumab, nivolumab, nofetumomab merpentan, obiltoxaximab, obinutuzumab, ocaratuzumab, ocrelizumab, odulimomab, ofatumumab, olaratumab, olokizumab, omalizumab, onartuzumab, ontuxizumab, opicinumab, oportuzumab monatox, oregovomab, orticumab, otelixizumab, otlertuzumab, oxelumab, ozanezumab, ozoralizumab, pagibaximab, palivizumab, panitumumab, pankomab, PankoMab-GEX, panobacumab, parsatuzumab, pascolizumab, pasotuxizumab, pateclizumab, patritumab, pembrolizumab, pemtumomab, perakizumab, pertuzumab, pexelizumab, pidilizumab, pinatuzumab vedotin, pintumomab, placulumab, polatuzumab vedotin, ponezumab, priliximab, pritoxaximab, pritumumab, quilizumab, racotumomab, radretumab, rafivirumab, ralpancizumab, ramucirumab, ranibizumab, raxibacumab, refanezumab, regavirumab, reslizumab, rilotumumab, rinucumab, risankizumab, rituximab, robatumumab, roledumab, romosozumab, rontalizumab, rovelizumab, ruplizumab, sacituzumab govitecan, samalizumab, sarilumab, satumomab pendetide, secukinumab, seribantumab, setoxaximab, sevirumab, sibrotuzumab, sifalimumab, siltuximab, simtuzumab, siplizumab, sirukumab, sofituzumab vedotin, solanezumab, solitomab, sonepcizumab, sontuzumab, stamulumab, sulesomab, suvizumab, tabalumab, tacatuzumab tetraxetan, tadocizumab, tafasitamab, talizumab, tanezumab, tanibirumab, taplitumomab paptox, tarextumab, tefibazumab, teleukin, telimomab aritox, tenatumomab, teneliximab, teplizumab, teprotumumab, tesidolumab, tetulomab, Thorium-227-Epratuzumab Conjugate, ticilimumab, tigatuzumab, tildrakizumab, tisotumab vedotin, tocilizumab, toralizumab, tosatoxumab, tositumomab, tovetumab, tralokinumab, trastuzumab, trastuzumab deruxtecan, trastuzumab emtansine, tregalizumab, tremelimumab, trevogrumab, tucotuzumab celmoleukin, tuvirumab, ublituximab, ulocuplumab, urelumab, urtoxazumab, utomilumab, ustekinumab, vadastuximab talirine, vandortuzumab vedotin, vantictumab, vanucizumab, vapaliximab, varlilumab, vatelizumab, vedolizumab, veltuzumab, vepalimomab, vesencumab, visilizumab, volociximab, vorsetuzumab mafodotin, votumumab, zalutumumab, zanolimumab, zatuximab, ziralimumab, zolimomab aritox, any fragments thereof, or any biosimilars thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of daratumumab, MOR202, SAR650984, MU1053, isatuximab, HexaBody-CD38, tafasitamab, or rituximab. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of daratumumab or a fragment thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fabregion, Fc region, or an IgG region of an antibody of MOR202 or a fragment thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of SAR650984 or a fragment thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain or a region of MU1053. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of Isatuximab or a fragment thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of HexaBody-CD38 or a fragment thereof. In some embodiments, the polypeptide constructs comprises an antigen binding domain, Fab region, Fc region, or an IgG region of an antibody of Rituximab or a fragment thereof.

[0175] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-TNF-alpha antibody. In some embodiments, the anti-TNF-alpha antibody is adalimumab. The heavy chain of adalimumab is provided below in SEQ ID NO: 42: MEFGLSWLFLVAILKGVQCEVQLVESGGGLVQPGRSLRLSCAASGFTFDDYAM HWVRQAPGKGLEWVSAITWNSGHIDYADSVEGRFTISRDNAKNSLYLQMNSLR AEDTAVYYCAKVSYLSTASSLDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTS GGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVP SSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFL FPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSD GSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 42)

[0176] The light chain of adalimumab is provided below in SEQ ID NO: 43: MDMRVPAQLLGLLLLWLRGARCDIQMTQSPSSLSASVGDRVTITCRASQGIRN YLAWYQQKPGKAPKLLIYAASTLQSGVPSRFSGSGSGTDFTLTISSLQPEDVA TYYCQRYNRAPYTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLN NFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHK VYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 43)

[0177] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against TNF alpha. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of adalimumab and the two light chains that are present in said antibody of the invention are both the light chain of adalimumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0178] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of adalimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of adalimumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of adalimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of adalimumab).

[0179] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD52 antibody. In some embodiments, the anti-CD52 antibody is alemtuzumab. The heavy chain of alemtuzumab is provided below in SEQ ID NO: 44: QVQLQESGPGLVRPSQTLSLTCTVSGFTFTDFYMNWVRQPPGRGLEWIGFIRD KAKGYTTEYNPSVKGRVTMLVDTSKNQFSLRLSSVTAADTAVYYCAREGHTAA PFDYWGQGSLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTC VVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 44)

[0180] The light chain of alemtuzumab is provided below in SEQ ID NO: 45: DIQMTQSPSSLSASVGDRVTITCKASQNIDKYLNWYQQKPGKAPKLLIYNTNN LQTGVPSRFSGSGSGTDFTFTISSLQPEDIATYYCLQHISRPRTFGQGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNR (SEQ ID NO: 45)

[0181] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD52. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of alemtuzumab and the two light chains that are present in said antibody of the invention are both the light chain of alemtuzumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0182] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of alemtuzumab, which is linked or fused (as further described herein) to a C1q binder (as furtherdescribed herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of alemtuzumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of alemtuzumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of alemtuzumab).

[0183] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-EGFR antibody. In some embodiments, the anti-EGFR antibody is cetuximab. The heavy chain of cetuximab is provided below in SEQ ID NO: 46: QVQLKQSGPGLVQPSQSLSITCTVSGFSLTNYGVHWVRQSPGKGLEWLGVIWS GGNTDYNTPFTSRLSINKDNSKSQVFFKMNSLQSNDTAIYYCARALTYYDYEF AYWGQGTLVTVSAASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVS WNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTK VDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVV VDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNV FSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 46)

[0184] The light chain of cetuximab is provided below in SEQ ID NO: 47: DILLTQSPVILSVSPGERVSFSCRASQSIGTNIHWYQQRTNGSPRLLIKYASE SISGIPSRFSGSGSGTDFTLSINSVESEDIADYYCQQNNNWPTTFGAGTKLEL KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 47).

[0185] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against EGFR. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of cetuximab and the two light chains that are present in said antibody of the invention are both the light chain of cetuximab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0186] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of cetuximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of cetuximab). In anotherembodiment, the invention relates to a polypeptide that comprises the light chain of cetuximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of cetuximab).

[0187] In other embodiments, the anti-EGFR antibody is trastuzumab. The heavy chain of trastuzumab is provided below in SEQ ID NO: 48: EVQLVESGGGLVQPGGSLRLSCAASGFNIKDTYIHWVRQAPGKGLEWVARIYP TNGYTRYADSVKGRFTISADTSKNTAYLQMNSLRAEDTAVYYCSRWGGDGFYA MDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 48)

[0188] The light chain of trastuzumab is provided below in SEQ ID NO: 49: DIQMTQSPSSLSASVGDRVTITCRASQDVNTAVAWYQQKPGKAPKLLIYSASF LYSGVPSRFSGSRSGTDFTLTISSLQPEDFATYYCQQHYTTPPTFGQGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 49)

[0189] In another aspect, the invention relates to an antibody of the invention against EGFR in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of trastuzumab and the two light chains that are present in said antibody of the invention are both the light chain of trastuzumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0190] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of trastuzumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of trastuzumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of trastuzumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of trastuzumab).

[0191] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD38 antibody. In some embodiments, the anti-CD38 antibody is daratumumab. The heavy chain of daratumumab is provided below in SEQ ID NO: 50: EVQLLESGGGLVQPGGSLRLSCAVSGFTFNSFAMSWVRQAPGKGLEWVSAISG SGGGTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYFCAKDKILWFGE PVFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPV TVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPS NTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVT CVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDW LNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLT CLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 50)

[0192] The light chain of daratumumab is provided below in SEQ ID NO: 51: EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASN RATGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQRSNWPPTFGQGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 51)

[0193] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD38. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of daratumumab and the two light chains that are present in said antibody of the invention are both the light chain of daratumumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0194] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of daratumumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of daratumumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of daratumumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of daratumumab).

[0195] In other embodiments, the anti-CD38 antibody is isatuximab. The heavy chain sequences of isatuximab is provided below in SEQ ID NO: 52 – SEQ ID NO: 53:QVQLVQSGAEVAKPGTSVKLSCKASGYTFTDYWMQWVKQRPGQGLEWIGTIYP GDGDTGYAQKFQGKATLTADKSSKTVYMHLSSLASEDSAVYYCARGDYYGSNS LDYWGQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 52) QVQLVQSGAEVAKPGTSVKLSCKASGYTFTDYWMQWVKQRPGQGLEWIGTIYP GDGDTGYAQKFQGKATLTADKSSKTVYMHLSSLASEDSAVYYCARGDYYGSNS LDYWGQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 53)

[0196] The light chain of isatuximab is provided below in SEQ ID NO: 54 – SEQ ID NO: 55: DIVMTQSHLSMSTSLGDPVSITCKASQDVSTVVAWYQQKPGQSPRRLIYSASY RYIGVPDRFTGSGAGTDFTFTISSVQAEDLAVYYCQQHYSPPYTFGGGTKLEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 54) DIVMTQSHLSMSTSLGDPVSITCKASQDVSTVVAWYQQKPGQSPRRLIYSASY RYIGVPDRFTGSGAGTDFTFTISSVQAEDLAVYYCQQHYSPPYTFGGGTKLEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 55)

[0197] In another aspect,, the invention relates to an antibody of the invention against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of isatuximab and the two light chains that are present in said antibody of the invention are both the light chain of isatuximab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0198] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of isatuximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of isatuximab). In anotherembodiment, the invention relates to a polypeptide that comprises the light chain of isatuximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of isatuximab).

[0199] In other embodiments, the anti-CD38 antibody is the Genmab CD38-targeting antibody known as “Clone 003” (see also WO2006 / 099875). The heavy chain of clone 003 is provided below: QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAFSWVRQAPGQGLEWMGRVIP FLGIANSAQKFQGRVTITADKSTSTAYMDLSSLRSEDTAVYYCARDDIAALGP FDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 94)

[0200] The light chain of clone 003 is provided below: DIQMTQSPSSLSASVGDRVTITCRASQGISSWLAWYQQKPEKAPKSLIYAASS LQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYNSYPRTFGQGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 95)

[0201] In another aspect,, the invention relates to an antibody of the invention against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of clone 003 and the two light chains that are present in said antibody of the invention are both the light chain of clone 003 (and which antibody of the invention also contains two C1q binders, as further described herein).

[0202] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of clone 003, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of clone 003). In another embodiment, the invention relates to a polypeptide that comprises the light chain of clone 003, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of clone 003).

[0203] In other embodiments, the anti-CD38 antibody is the Morphosys CD38-targeting antibody known as “Moro 3080”. The heavy chain of Moro 3080 is provided below: QVQLVESGGGLVQPGGSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVSNIYS DGSNTFYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARNMYRWPFH YFFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPV TVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPS NTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVT CVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDW LNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLT CLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 99)

[0204] The light chain of Moro 3080 is provided below: DIELTQPPSVSVAPGQTARISCSGDNIGNKYVSWYQQKPGQAPVVVIYGDNNR PSGIPERFSGSNSGNTATLTISGTQAEDEADYYCSSYDSSYFVFGGGTKLTVL GQPKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGV ETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS (SEQ ID NO: 100)

[0205] In another aspect, the invention relates to an antibody of the invention against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of Moro 3080 and the two light chains that are present in said antibody of the invention are both the light chain of Moro 3080 (and which antibody of the invention also contains two C1q binders, as further described herein).

[0206] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of Moro 3080, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of Moro 3080). In another embodiment, the invention relates to a polypeptide that comprises the light chain of Moro 3080, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of Moro 3080).

[0207] In other embodiments, the anti-CD38 antibody is the Morphosys CD38-targeting antibody known as “Moro 3087”. The heavy chain of Moro 3087 is provided below: QVQLVESGGGLVQPGGSLRLSCAASGFTFSSYYMNWVRQAPGKGLEWVSGISG DPSNTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARDLPLVYTG FAYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO:243)

[0208] The light chain of Moro 3087 is provided below: DIELTQPPSVSVAPGQTARISCSGDNLRHYYVYWYQQKPGQAPVLVIYGDSKR PSGIPERFSGSNSGNTATLTISGTQAEDEADYYCQTYTGGASLVFGGGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO:242)

[0209] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of Moro 3087 and the two light chains that are present in said antibody of the invention are both the light chain of Moro 3087 (and which antibody of the invention also contains two C1q binders with reduced affinity for C1q, as further described herein).

[0210] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of Moro 3087, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of Moro 3087). In another embodiment, the invention relates to a polypeptide that comprises the light chain of Moro 3087, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of Moro 3087).

[0211] In other embodiments, the anti-CD38 antibody is the Morphosys CD38-targeting antibody known as “Moro 3088”. The heavy chain of Moro 3088 is provided below: QVQLVESGGGLVQPGGSLRLSCAASGFTFSSYAMNWVRQAPGKGLEWVSGISS WGSSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAREDGSYMTD YFAYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTC VVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCSVMHEALHNHYTQKSLSLSPGK(SEQ ID NO:249)

[0212] The light chain of Moro 3088 is provided below: DIELTQPPSVSVAPGQTARISCSGDNIGHYYVSWYQQKPGQAPVLVIYSDSNR PSGIPERFSGSNSGNTATLTISGTQAEDEADYYCQSYNGTYVFGGGTKVEIKR TVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQE SVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID: 248)

[0213] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of Moro 3088 and the two light chains that are present in said antibody of the invention are both the light chain of Moro 3088 (and which antibody of the invention also contains two C1q binders with reduced affinity for C1q, as further described herein).

[0214] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of Moro 3088, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of Moro 3088). In another embodiment, the invention relates to a polypeptide that comprises the light chain of Moro 3088, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of Moro 3088).

[0215] In other embodiments, the anti-CD38 antibody is mezagitumab. The heavy chain of mezagitumab is provided below: EVQLLESGGGLVQPGGSLRLSCAASGFTFDDYGMSWVRQAPGKGLEWVSDISWN GGKTHYVDSVKGQFTISRDNSKNTLYLQMNSLRAEDTAVYYCARGSLFHDSSGF YFGHWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTK VDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVV DVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKE YKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCS VMHEALHNHYTQKSLSLSPG(SEQ ID NO:255)

[0216] The light chain of mezagitumab is provided below: QSVLTQPPSASGTPGQRVTISCSGSSSNIGDNYVSWYQQLPGTAPKLLIYRDSQ RPSGVPDRFSGSKSGTSASLAISGLRSEDEADYYCQSYDSSLSGSVFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGE C(SEQ ID: 254)

[0217] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of mezagitumab and the two light chains that are present in said antibody of the invention are both the light chain of mezagitumab (and which antibody of the invention also contains two C1q binders with reduced affinity for C1q, as further described herein).

[0218] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of mezagitumab, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of mezagitumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of mezagitumab, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of mezagitumab).

[0219] In other embodiments, the anti-CD38 antibody is the Genmab CD38-targeting antibody known as “Clone 024” (see also WO2006 / 099875). The heavy chain of clone 024 is provided below: EVQLVQSGAEVKKPGESLKISCKGSGYSFSNYWIGWVRQMPGKGLEWMGIIYPH DSDARYSPSFQGQVTFSADKSISTAYLQWSSLKASDTAMYYCARHVGWGSRYWY FDLWGRGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVS WNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKV DKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVD VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEY KCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFY PSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSV MHEALHNHYTQKSLSLSPGK(SEQ ID NO: 260)

[0220] The light chain of clone 024 is provided below: EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPGLLIYDASN RASGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQRSNWPLTFGGGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 263)

[0221] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of clone 024 and the two light chains that are present in said antibody of the invention are both the light chain of clone 024 (and which antibody of the invention also contains two C1q binders with reduced affinity for C1q, as further described herein).

[0222] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of clone 024, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of clone 024). In another embodiment, the invention relates to a polypeptide that comprises the light chain of clone 024, which is linked or fused (as further described herein) to a C1q binder with reduced affinity for C1q (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of clone 024).

[0223] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of MU1053. The amino acid sequence of MU1053 is provided below: QVQLQESGGGLVQAGGSLRLSCTGSGRTFRNYPMAWFRQAPGKEREFVAGITWVGASTLYA DFAKGRFTISRDNAKNTVYLQMNSLKPEDTAVYSCAAGRGIVAGRIPAEYADWGQGTQVTV SS (SEQ ID NO: 56)

[0224] In other embodiments, the anti-CD38 antibody is the anti-CD38 antibody CM313. The heavy chain of CM313 is provided below: EVQLKQSGPGLMQPSQSLSITCTVSGFSLTSYGIHWLRQSPGKGLEWLGVIWRGGSTDYNAAFMSRL SITKDNSKSQVFFKMNSLQGDDTAIYYCAKGKVTTGFYFDFWGQGTTLTVSSASTKGPSVFPLAPSS KSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYI CNVNHKPSNTKVDKKAEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDV SHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIE KTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDS DGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 271)

[0225] The light chain of CM313 is provided below:

[0226] DIQMTQSSSSFSVSLGDRVTITCKASEDIYNRLVWYQQKPGNAPGLLISGVTSLETG VPSRFSGSGSGKDYTLTITSLQTEDVATYYCQQYWSTPYTFGGGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKV YACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 272)

[0227] In another aspect,, the invention relates to an antibody of the invention against CD38 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of CM313 and the two light chains that are present in said antibody of the invention are both the light chain of CM313 (and which antibody of the invention also contains two C1q binders, as further described herein).

[0228] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of CM313, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of CM313). In another embodiment, the invention relates to a polypeptide that comprises the light chain of CM313, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of CM313).

[0229] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-RANKL antibody. In some embodiments, the anti-RANKL antibody is denosumab. The heavy chain of denosumab is provided below in SEQ ID NO: 57: EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYAMSWVRQAPGKGLEWVSGITG SGGSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAKDPGTTVIM SWFDPWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPV TVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPS NTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVT CVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDW LNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLT CLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 57)

[0230] The light chain of denosumab is provided below in SEQ ID NO: 58: EIVLTQSPGTLSLSPGERATLSCRASQSVRGRYLAWYQQKPGQAPRLLIYGAS SRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVFYCQQYGSSPRTFGQGTKVE IKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGN SQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNR GEC (SEQ ID NO: 58)

[0231] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against RANK-L. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of denosumab and the two light chains that are present in said antibody of the invention are both the light chain of denosumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0232] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of denosumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of denosumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of denosumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of denosumab).

[0233] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-IL-4 antibody. In some embodiments, the anti-IL-4 antibody is duplimab. The heavy chain of duplimab is provided below in SEQ ID NO: 59: EVQLVESGGGLEQPGGSLRLSCAGSGFTFRDYAMTWVRQAPGKGLEWVSSISG SGGNTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAKDRLSITIR PRYYGLDVWGQGTTVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFP EPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDH KPSNTKVDKRVESKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVT CVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDW LNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLT CLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQE GNVFSCSVMHEALHNHYTQKSLSLSLG (SEQ ID NO: 59)

[0234] The light chain of duplimab is provided below in SEQ ID NO: 60: DIVMTQSPLSLPVTPGEPASISCRSSQSLLYSIGYNYLDWYLQKSGQSPQLLI YLGSNRASGVPDRFSGSGSGTDFTLKISRVEAEDVGFYYCMQALQTPYTFGQG TKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNAL QSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTK SFNRGEC (SEQ ID NO: 60)

[0235] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against IL-4. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention areboth the heavy chain of duplimab and the two light chains that are present in said antibody of the invention are both the light chain of duplimab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0236] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of duplimab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of duplimab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of duplimab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of duplimab).

[0237] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD33 antibody. In some embodiments, the anti-CD33 antibody is gemtuzumab ozogamicin. The heavy chain of gemtuzumab ozogamicin is provided below in SEQ ID NO: 61: EVQLVQSGAEVKKPGSSVKVSCKASGYTITDSNIHWVRQAPGQSLEWIGYIYP YNGGTDYNQKFKNRATLTVDNPTNTAYMELSSLRSEDTAFYYCVNGNPWLAYW GQGTLVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNS GALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDK RVESKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQE DPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCK VSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPS DIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVM HEALHNHYTQKSLSLSLGK (SEQ ID NO: 61)

[0238] The light chain of gemtuzumab ozogamicin is provided below in SEQ ID NO: 62: DIQLTQSPSTLSASVGDRVTITCRASESLDNYGIRFLTWFQQKPGKAPKLLMY AASNQGSGVPSRFSGSGSGTEFTLTISSLQPDDFATYYCQQTKEVPWSFGQGT KVEVKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQ SGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKS FNRGEC (SEQ ID NO: 62)

[0239] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD33. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of gemtuzumab ozogamicin and the two light chains that are present in saidantibody of the invention are both the light chain of gemtuzumab ozogamicin (and which antibody of the invention also contains two C1q binders, as further described herein).

[0240] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of gemtuzumab ozogamicin, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of gemtuzumab ozogamicin). In another embodiment, the invention relates to a polypeptide that comprises the light chain of gemtuzumab ozogamicin, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of gemtuzumab ozogamicin).

[0241] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CTLA-4 antibody. In some embodiments, the anti-CTLA-4 antibody is ipilimumab. The heavy chain of ipilimumab is provided below in SEQ ID NO: 63: QVQLVESGGGVVQPGRSLRLSCAASGFTFSSYTMHWVRQAPGKGLEWVTFISY DGNNKYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAIYYCARTGWLGPFD YWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSW NSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKV DKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVV DVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVF SCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 63)

[0242] The light chain of ipilimumab is provided below in SEQ ID NO: 64: EIVLTQSPGTLSLSPGERATLSCRASQSVGSSYLAWYQQKPGQAPRLLIYGAF SRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGSSPWTFGQGTKVE IKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGN SQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNR GEC (SEQ ID NO: 64)

[0243] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CTLA-4. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of ipilimumab and the two light chains that are present in said antibody of the invention are both the light chain of ipilimumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0244] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of ipilimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of ipilimumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of ipilimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of ipilimumab).

[0245] In some embodiments, the anti-CTLA-4 antibody is tremelimumab. The heavy chain of tremelimumab is provided below in SEQ ID NO: 65: QVQLVESGGGVVQPGRSLRLSCAASGFTFSSYTMHWVRQAPGKGLEWVTFISY DGNNKYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAIYYCARTGWLGPFD YWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSW NSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKV DKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVV DVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVF SCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 65)

[0246] The light chain of tremelimumab is provided below in SEQ ID NO: 66: EIVLTQSPGTLSLSPGERATLSCRASQSVGSSYLAWYQQKPGQAPRLLIYGAF SRATGIPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGSSPWTFGQGTKVE IKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGN SQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNR GEC (SEQ ID NO: 66)

[0247] In another aspect,, the invention relates to an antibody of the invention against CTLA- 4 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of tremelimumab and the two light chains that are present in said antibody of the invention are both the light chain of tremelimumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0248] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of tremelimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of tremelimumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain oftremelimumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of tremelimumab).

[0249] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-integrin antibody. In some embodiments, the anti-integrin antibody is natalizumab. The heavy chain of natalizumab is provided below in SEQ ID NO: 67: QVQLVQSGAEVKKPGASVKVSCKASGFNIKDTYIHWVRQAPGQRLEWMGRIDP ANGYTKYDPKFQGRVTITADTSASTAYMELSSLRSEDTAVYYCAREGYYGNYG VYAMDYWGQGTLVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEP VTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKP SNTKVDKRVESKYGPPCPSCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLN GKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGN VFSCSVMHEALHNHYTQKSLSLSLGK (SEQ ID NO: 67)

[0250] The light chain of natalizumab is provided below in SEQ ID NO: 68: DIQMTQSPSSLSASVGDRVTITCKTSQDINKYMAWYQQTPGKAPRLLIHYTSA LQPGIPSRFSGSGSGRDYTFTISSLQPEDIATYYCLQYDNLWTFGQGTKVEIK RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQ ESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGE C (SEQ ID NO: 68)

[0251] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against an integrin (in particular against alpha-4 integrin). In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of natalizumab and the two light chains that are present in said antibody of the invention are both the light chain of natalizumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0252] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of natalizumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of natalizumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of natalizumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of natalizumab).

[0253] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-PD-1 antibody. In some embodiments, the anti-PD-1 antibody is nivolumab. The heavy chain of nivolumab is provided below in SEQ ID NO: 69: QVQLVESGGGVVQPGRSLRLDCKASGITFSNSGMHWVRQAPGKGLEWVAVIWY DGSKRYYADSVKGRFTISRDNSKNTLFLQMNSLRAEDTAVYYCATNDDYWGQG TLVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGAL TSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVE SKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPE VQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSN KGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIA VEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEA LHNHYTQKSLSLSLGK (SEQ ID NO: 69)

[0254] The light chain of nivolumab is provided below in SEQ ID NO: 70: EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASN RATGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQSSNWPRTFGQGTKVEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 70)

[0255] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against PD-1. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of nivolumab and the two light chains that are present in said antibody of the invention are both the light chain of nivolumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0256] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of nivolumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of nivolumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of nivolumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of nivolumab).

[0257] In other embodiments, the anti-PD-1 antibody is pembrolizumab. The heavy chain of pembrolizumab is provided below in SEQ ID NO: 71.QVQLVQSGVEVKKPGASVKVSCKASGYTFTNYYMYWVRQAPGQGLEWMGGINP SNGGTNFNEKFKNRVTLTTDSSTTTAYMELKSLQFDDTAVYYCARRDYRFDMG FDYWGQGTTVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNT KVDKRVESKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVD VSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKE YKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQQGNVFS CSVMHEALHNHYTQKSLSLS (SEQ ID NO: 71)

[0258] The light chain of pembrolizumab is provided below in SEQ ID NO: 72. EIVLTQSPATLSLSPGERATLSCRASKGVSTSGYSYLHWYQQKPGQAPRLLIY LASYLESGVPARFSGSGSGTDFTLTISSLEPEDFAVYYCQHSRDLPLTFGGGT KVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQ SGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKS FNRGEC (SEQ ID NO: 72)

[0259] In another aspect,, the invention relates to an antibody of the invention against PD-1 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of pembrolizumab and the two light chains that are present in said antibody of the invention are both the light chain of pembrolizumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0260] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of pembrolizumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of pembrolizumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of pembrolizumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of pembrolizumab).

[0261] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD20 antibody. In some embodiments, the anti-CD20 antibody is rituximab. The heavy chain of rituximab is provided below in SEQ ID NO: 73: QVQLQQPGAELVKPGASVKMSCKASGYTFTSYNMHWVKQTPGRGLEWIGAIYP GNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCARSTYYGGDW YFNVWGAGTTVTVSAASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKKAEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTC VVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 73)

[0262] The light chain of rituximab is provided below in SEQ ID NO: 74: QIVLSQSPAILSASPGEKVTMTCRASSSVSYIHWFQQKPGSSPKPWIYATSNL ASGVPVRFSGSGSGTSYSLTISRVEAEDAATYYCQQWTSNPPTFGGGTKLEIK RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQ ESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGE C (SEQ ID NO: 74)

[0263] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD20. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of rituximab and the two light chains that are present in said antibody of the invention are both the light chain of rituximab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0264] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of rituximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of rituximab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of rituximab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of rituximab).

[0265] In other embodiments, the anti-CD20 antibody is 11B8. The heavy chain of 11B8 is provided below in SEQ ID NO: 105. The light chain of 11B8 in SEQ ID NO: 106.

[0266] In another aspect,, the invention relates to an antibody of the invention against CD20 in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of 11B8 and the two light chains that are present in said antibody of the invention are both the light chain of 11B8 (and which antibody of the invention also contains two C1q binders, as further described herein).

[0267] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of 11B8, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of 11B8). In anotherembodiment, the invention relates to a polypeptide that comprises the light chain of 11B8, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of 11B8).

[0268] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD-19 antibody. In some embodiments, the anti-CD19 antibody is tafasitamab. The heavy chain of tafasitamab is provided below in SEQ ID NO: 75: EVQLVESGGGLVKPGGSLKLSCAASGYTFTSYVMHWVRQAPGKGLEWIGYINP YNDGTKYNEKFQGRVTISSDKSISTAYMELSSLRSEDTAMYYCARGTYYYGTR VFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKKVEPKSCDKTHTCPPCPAPELLGGPDVFLFPPKPKDTLMISRTPEVTC VVVDVSHEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTFRVVSVLTVVHQDWL NGKEYKCKVSNKALPAPEEKTISKTKGQPREPQVYTLPPSREEMTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPMLDSDGSFFLYSKLTVDKSRWQQG NVFSCSVMHEALHNHYTQKSLSLSPGK(SEQ ID NO: 75)

[0269] The light chain of tafasitamab is provided below in SEQ ID NO: 76: DIVMTQSPATLSLSPGERATLSCRSSKSLQNVNGNTYLYWFQQKPGQSPQLLI YRMSNLNSGVPDRFSGSGSGTEFTLTISSLEPEDFAVYYCMQHLEYPITFGAG TKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNAL QSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTK SFNRGEC (SEQ ID NO: 76)

[0270] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD19. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of tafasitamab and the two light chains that are present in said antibody of the invention are both the light chain of tafasitamab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0271] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of tafasitamab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of tafasitamab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of tafasitamab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well asto an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of tafasitamab).

[0272] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-CD137 antibody. In some embodiments, the anti-CD137 antibody is urelumab. The heavy chain of urelumab is provided below in SEQ ID NO: 77: QVQLQQWGAGLLKPSETLSLTCAVYGGSFSGYYWSWIRQSPEKGLEWIGEINH GGYVTYNPSLESRVTISVDTSKNQFSLKLSSVTAADTAVYYCARDYGPGNYDW YFDLWGRGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKKVEPKSCAAAHHHHHHHH (SEQ ID NO: 77) or QVQLQQWGAGLLKPSETLSLTCAVYGGSFSGYYWSWIRQSPEKGLEWIGEINH GGYVTYNPSLESRVTISVDTSKNQFSLKLSSVTAADTAVYYCARDYGPGNYDW YFDLWGRGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSN TKVDKKVEPKSCAAA (SEQ ID NO: 300)

[0273] The light chain of urelumab is provided below in SEQ ID NO: 78: EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASN RATGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQRSNWPPALTFGGGTKV EIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSG NSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFN RGEC (SEQ ID NO: 78)

[0274] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against CD137. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of urelumab and the two light chains that are present in said antibody of the invention are both the light chain of urelumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0275] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of urelumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of urelumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of urelumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of urelumab).

[0276] In some embodiments, the polypeptide constructs comprises a Fab region, Fc region, or an IgG region of an anti-IL-12 and anti-IL-23 antibody. In some embodiments, the anti-IL-12 and anti-IL-23 antibody is ustekinumab. The heavy chain of ustekinumab is provided below in SEQ ID NO: 79: EVQLVQSGAEVKKPGESLKISCKGSGYSFTTYWLGWVRQMPGKGLDWIGIMSP VDSDIRYSPSFQGQVTMSVDKSITTAYLQWNSLKASDTAMYYCARRRPGQGYF DFWGQGTLVTVSSSSTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVS WNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTK VDKRVEPKSCDKTH (SEQ ID NO: 79)

[0277] The light chain of ustekinumab is provided below in SEQ ID NO: 80: DIQMTQSPSSLSASVGDRVTITCRASQGISSWLAWYQQKPEKAPKSLIYAASS LQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYNIYPYTFGQGTKLEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNS QESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRG EC (SEQ ID NO: 80)

[0278] In some embodiments, the invention relates to an antibody of the invention (as further described herein) that is directed against IL-12 / IL-23. In particular, the invention relates to such an antibody of the invention in which the two heavy chains that are present in said antibody of the invention are both the heavy chain of ustekinumab and the two light chains that are present in said antibody of the invention are both the light chain of ustekinumab (and which antibody of the invention also contains two C1q binders, as further described herein).

[0279] In another embodiment, the invention relates to a polypeptide that comprises the heavy chain of ustekinumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such heavy chains (and two suitable light chains, that are preferably each the light chain of ustekinumab). In another embodiment, the invention relates to a polypeptide that comprises the light chain of ustekinumab, which is linked or fused (as further described herein) to a C1q binder (as further described herein); as well as to an antibody or antibody construct that comprises two such light chains (and two suitable heavy chains, that are preferably each the heavy chain of ustekinumab).

[0280] In some embodiments, the polypeptide construct comprises an Fc region having one or more amino acid modification(s) with respect to a wildtype Fc region that improves the serum half- life of the antibody or antigen-binding fragment thereof. For example, the polypeptide construct can comprise a modified IgG Fc region for improved serum half-life having one or more of the following modifications with respect to a wildtype IgG Fc region: M252Y, S254T, T256E, M428L, N434S,T256D, T307R, Q311V, N315D, N286D, T307R, H285N, or T307Q. In some embodiments, a polypeptide construct can comprise a modified IgG Fc region for improved serum half-life having one of the following sets of modifications: M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, or T256D / H285D / T307R / Q311V / A378V.

[0281] In some embodiments, a polypeptide construct can comprise an Fc region having one or more deletions with respect to a wildtype Fc region for improved serum half-life. For example, an Fc region can comprise a deletion of a CH2 domain, a CH3 domain, or a portion thereof for improved serum half-life. In some embodiments, an Fc region can comprise a deletion of a C-terminal amino acid in a CH3 domain, such as a C-terminal lysine, for improved serum half-life. In some embodiments, an Fc region can comprise one or more modifications with respect to a wildtype Fc region for improved activity (such as increased antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP)). In some embodiments, an Fc region can comprise one or more modifications with respect to a wildtype Fc region for improved binding to a C1q complement factor.

[0282] In some embodiments, the polypeptide constructs provided herein, when administered to a population of cells or when administered to a subject, increase ADCC and / or complement activation relative to a comparable polypeptide construct that has not been modified.

[0283] In some embodiments, the polypeptide constructs can further comprise a glycan, a PEG, a nucleic acid, a protein, such as albumin, Fc-fusion or linked other chemical groups, such as small chemical molecules. In some embodiments, the polypeptide construct further comprises an albumin binding nanobody (Nb). In some embodiments, the albumin binding Nb is directly linked on an antigen-binding moiety. In some embodiments, the polypeptide construct comprising the albumin- binding Nb has increased the in vitro half-life of the polypeptide construct. In some embodiments, the polypeptide construct comprising the albumin-binding Nb has increased the in vivo half-life of the polypeptide construct. The term “half-life” as used herein refers to the time taken for the serum concentration of the polypeptide construct or any fragment thereof to be reduced by 50%, in vivo, for example due to degradation of the polypeptide construct or composition and / or clearance or sequestration of the polypeptide construct or compound by natural mechanisms. The in vivo half-lifeof the polypeptide construct of the present disclosure can be determined in any manner known per se, such as by pharmacokinetic analysis. Pharmaceutical Compositions

[0284] One aspect of the present disclosure relates to a composition comprising one or more of the polypeptide constructs provided herein. In some embodiments, the composition is a pharmaceutical composition. A pharmaceutical composition is a composition comprising one or more substances that have medicinal properties, together with a pharmaceutical acceptable carrier. Details of pharmaceutical compositions are provided herein below.

[0285] The polypeptide constructs can be formulated as pharmaceutical compositions and administered to a mammalian subject, such as a human subject in a variety of forms adapted to the chosen route of administration. Routes for administration include, for example, intravenous, intra- arterial, subcutaneous, intramuscular, intraperitoneal, intravitreal and other routes selected by one of skill in the art. Administration can also be achieved by nebulization. In another approach, the polypeptide constructs can be administered as DNA by AAV and then expressed from the vector Administration forms are described elsewhere herein.

[0286] In some embodiments, solutions of the polypeptide constructs can for example be prepared in water or saline, and optionally mixed with a nontoxic surfactant. In some embodiments, the pharmaceutical compositions as described herein are formulated for intravenous or intra-arterial administration may include sterile aqueous solutions that may also contain buffers, liposomes, diluents and other suitable additives. In some embodiments, the pharmaceutical composition can also comprise or include serum.

[0287] In some embodiments, the pharmaceutical composition is in a dosage form. In some embodiments, the dosage forms are suitable for injection or infusion can include sterile aqueous solutions or dispersions comprising the polypeptide constructs that are adapted for administration by encapsulation in liposomes. The ultimate dosage form must be sterile, fluid and stable under the conditions of manufacture and storage.

[0288] Sterile injectable solutions are prepared by incorporating the polypeptide constructs in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filter sterilization. Methods of Treating a Disease

[0289] The polypeptide constructs provided herein can be used for both in vivo and in vitro methods as well as medical and non-medical procedures. In some embodiments, the polypeptide constructs provided herein are provided for use as a medicament. In certain embodiments, the polypeptide constructs and compositions are provided for treatment of a disorder, a clinical or physiological condition associated with complement activity. The polypeptide constructs and compositions can also be applied for use in the preparation of a medicament, for example for the treatment of a disease or a disorder, a clinical or physiological condition associated with complement activity.

[0290] In some embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in a disease. Accordingly, the polypeptide constructs may be used in the treatment of the disease in which the target protein is implicated. In some embodiments, the disease is a cancer, an inflammatory disease, an autoimmune disease, an infectious disease, a cardiac disease, a genetic disease or a neurological disease. In some embodiments, the disease is a is a cancer, an autoimmune disease, an inflammatory disease, or a neurological disease.

[0291] In certain embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in a cancer. Accordingly, the polypeptide constructs may be used in the treatment of cancer, such as in the treatment of the cancer in which the target protein is implicated. The term “cancer” as used herein refers to proliferative diseases, such as lymphomas, carcinoma, lymphoma, blastoma, sarcoma, leukemia, lymphocytic leukemias, lung cancer, non-small cell lung (NSCL) cancer, bone cancer, bronchioloalviolar cell lung cancer, pancreatic cancer, skin cancer, cancer of the head or neck, cutaneous or intraocular melanoma, uterine cancer, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, gastric cancer, colorectal cancer (CRC), pancreatic cancer, breast cancer, triple-negative breast cancer, uterine cancer, carcinoma of the fallopian tubes, carcinoma of the endometrium, carcinoma of the cervix, carcinoma of the vagina, carcinoma of the vulva, Hodgkin's Disease, cancer of the esophagus, cancer of the small intestine, cancer of the endocrine system, cancer of the thyroid gland, cancer of the parathyroid gland, cancer of the adrenal gland, sarcoma of soft tissue, cancer of the urethra, cancer of the penis, prostate cancer, cancer of the bladder, cancer of the kidney or ureter, renal cell carcinoma, carcinoma of the renal pelvis, mesothelioma, hepatocellular cancer, biliary cancer, neoplasms of the central nervous system (CNS), spinal axis tumors, brain stem glioma, glioblastoma multiforme, astrocytomas, schwanomas, ependymonas, medulloblastomas, meningiomas, squamous cell carcinomas, pituitary adenoma and Ewings sarcoma, melanoma, multiple myeloma, B-cell cancer (lymphoma), chroniclymphocytic leukemia (CLL), acute lymphoblastic leukemia (ALL), hairy cell leukemia, chronic myeloblastic leukemia, including refractory versions of any of the above cancers, or a combination of one or more of the above cancers. In some embodiments, the cancer is a breast cancer, a colorectal cancer, a lung cancer, a leukemia, a bladder cancer, a lymphoma, a melanoma, a carcinoma, a kidney cancer, a prostate cancer, a bone cancer, a brain tumor, an adenocarcinoma, an adrenal cancer, a bile duct cancer, a cervical cancer, a pancreatic cancer, a thyroid cancer, an appendix cancer, a myeloma, a sarcoma, a cancer that primarily affects minors or children, or any combination thereof.

[0292] In some embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in an inflammatory disease. Accordingly, the polypeptide constructs may be used in the treatment of inflammatory disease, such as in the treatment of the inflammatory disease in which the target protein is implicated. In some embodiments, the inflammatory disease can include but is not limited to fatty liver disease, endometriosis, type 1 diabetes mellitus, type 2 diabetes mellitus, asthma, obesity, inflammatory bowel disease, rheumatoid arthritis, colitis, gout, sinusitis, vasculitis, ankylosing spondylitis, or an autoimmune disease. In other embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in an inflammatory disease that is an autoimmune disease. The term “autoimmune disease” as used herein refers to a disease that results when a subject’s immune system is overactive causing it to attack and damage tissues in the subject’s body. In some embodiments, the autoimmune disease can include but is not limited to lupus, rheumatoid arthritis, type 1 diabetes, multiple sclerosis, psoriasis, Grave’s disease, inflammatory bowel disease, scleroderma, Hashimoto thyroiditis, Sjögren syndrome, Celiac disease, Myasthenia gravis, Addison's disease, alopecia areata, autoimmune angioedema, or vitiligo.

[0293] In some embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in a neurological disease. Accordingly, the polypeptide constructs may be used in the treatment of neurological disease, such as in the treatment of the neurological disease in which the target protein is implicated. In some embodiments, the neurological disease can include but is not limited to epilepsy, dementia, stroke, headaches, Cerebral palsy, Multiple sclerosis, Amyotrophic lateral sclerosis, Meningitis, acute spinal cord injury, encephalitis, neuronal migration disorder, spina bifida, Barth syndrome, cervical spinal stenosis, Lewy body dementia, or muscular dystrophy.

[0294] In some embodiments, the polypeptide constructs as disclosed herein comprise an antigen-binding moiety that binds to a target protein implicated in an infectious disease. Accordingly, the polypeptide constructs may be used in the treatment of infectious disease, such as in the treatmentof the infectious disease in which the target protein is implicated. For example, in some aspects, the infectious disease can include but is not limited to a chronic viral infection like HIV (human immunodeficiency virus), HBV (hepatitis B virus), HCV (hepatitis C), HSV1 (herpes simplex virus type 1), HSV2 (herpes simplex virus type 2), CMV (cytomegalovirus), LCMV (lymphocytic choriomeningitis virus) or EBV (Epstein-Barr virus). In some embodiments, the infectious disease is hepatitis A, hepatitis B, hepatitis C, hepatitis D, hepatitis E, bacterial infections, fungal infections, protozoal infections or parasitic infections.

[0295] In some other embodiments, the polypeptide construct as described herein relates to a method of treating a disorder, a clinical or physiological condition associated with complement regulation, such as complement activation, said method comprising administering a therapeutically effective amount of a polypeptide construct or composition as defined herein to a subject in need thereof. The polypeptide constructs as described herein can be used alone or coupled to, or combined with, therapeutically useful agents. The polypeptide constructs can be administered to mammals suffering from any disease caused by dysregulation or over activation of the complement system or any of the diseases or clinical conditions mentioned herein. Such administration can provide therapeutic and curative treatments, as well as prophylactic, preventative and / or ameliorating measures. Methods of reducing antibody-therapy induced side effects

[0296] In some embodiments, the first complement factor-engaging domain and / or the second complement factor-engaging domain can activate human complement system. The complement system is part of the innate immune system and plays an important role in protection against invading microorganisms and in maintenance of homoeostasis. More than 50 proteins and protein fragments make up the complement system, including serum proteins, serosal proteins, and cell membrane bound receptors and regulatory proteins. A subset of the complement proteins circulates as inactive precursors (pro-proteins). When stimulated by one of several triggers, proteases in the system cleave specific proteins to initiate an amplifying cascade of further cleavages. The end-result of this activation cascade includes massive amplification of the response, enhanced phagocytosis and pathogen lysis, clearance of immune complexes and apoptotic cells, inflammation, stimulation of adaptive immune responses and assembly of the cell-killing membrane attack complex. Uncontrolled activation or lack of proper regulation of complement is involved in a range of diseases and the polypeptide constructsdescribed herein provides means for pharmacological regulation of the complement cascade in order to ameliorate disease outcome.

[0297] Accordingly, the polypeptide constructs or compositions as described herein can be used to reduce side effects associated with uncontrolled or poorly regulated complement activation. In some embodiments, the polypeptide constructs or compositions as described herein can be used in a method of reducing side-effects associated with an IgG antibody-based therapy. In some embodiments, the antigen-binding moiety of the constructs binds CD38. In some embodiments, the administering results in reduction of one or more side effects as compared to the administering a comparable amount of the IgG antibody-based therapy. In some embodiments, the one or more side effects comprise allergic reactions such as hives or itching, nausea, vomiting, fatigue, fever, chills, malaise, skin rashes, low blood pressure, lethargy, or any combination thereof. EXAMPLES

[0298] For a better understanding of the present disclosure and of its many advantages, the following examples are given by way of illustration and without limiting the scope of this disclosure. For further experimental details, reference is also made to the figures and examples of the International application of applicant / assignee entitled “Improved antibodies and antibody constructs against CD38” with the same filing date as the present application and to the International application of applicant / assignee entitled “Improved antibodies and antibody constructs against CD20” with the same filing date as the present application. EXAMPLE 1. Generation and Evaluation of Polypeptide Constructs Comprising C1q Complement Factor-engaging Domains. Generation of Polypeptide Constructs

[0299] A polypeptide construct having a first complement factor-engaging domain at the N- terminus, an antigen-binding moiety in the middle and a second complement factor-engaging domain in the C-terminal of the peptide chain (FIG. 1A) was designed in silico. Several affinity variants of the polypeptide constructs comprising C1q complement factor-engaging domains as disclosed herein were designed and tested in this format.

[0300] Genes were cloned into a pET22b vector containing a C-terminal HIS-tag. The plasmids were transformed in to BL21 (DE3) cells, plated on LB-agar plates containing 100 μg / ml ampicillin and incubated overnight (ON) at 37°C. After 24 hours, a single colony was inoculated in 50 ml Terrific Broth (TB) media containing 100 μg / ml ampicillin and grown at 37°C shaking until anoptical density at 600 nm of >2. Cells were added Isopropyl - d-1-thiogalactopyranoside (IPTG) to a final concentration of 1 mM and incubated at 30°C shaking overnight. Cells were centrifuged for 15 minutes at 4000 g and resuspended in 30 ml of PBS containing 1 mM Benzamidine, and 0.1 mM PMSF. Cells were opened with sonication on wet ice and subsequently centrifuged for 20 minutes at 15,000×g at 4°C. Supernatants were added to a 0.5 ml Nickel NTA (Ni-NTA) slurry and incubated rolling at 4°C for 30 min. Beads were decanted on a gravity column and washed with 2 x 50 ml cold PBS containing 500 sodium chloride (wash buffer). The polypeptide constructs as described herein were then eluted with wash buffer containing 300 mM imidazole at a pH 8.0. Polypeptide purity was evaluated by SDS-PAGE and polypeptide constructs were then dialyzed against PBS overnight at 4°C. Samples were centrifuged for 10 minutes at 4000 rpm at 4°C and the polypeptide constructs was concentrated to approximate 0.5 ml and loaded on a Superdex 75 Increase 10 / 300 GL column in PBS. Eluted fractions containing polypeptide constructs were analyzed by SDS-PAGE and fractions containing the polypeptide constructs were pooled. Complement Dependent Cytotoxicity (CDC) Assays

[0301] To evaluate activity, the polypeptide constructs were analyzed in complement dependent cytotoxicity (CDC) assays on cells expressing CD38, including the B cell lymphoma cell line WSU-DLCL2.

[0302] WSU-DLCL2 cells were maintained in high glucose Roswell Park Memorial Institute (RPMI) medium or RPMI 1640 + 10% heat inactivated FBS + 100U / ml Pen / Strep at 37°C, 8% CO2. Cells were maintained at 0.5-1.5 x 106 / ml and split 1:3-1:5 every 2-3 days. On the day of the CDC assay, cells were counted, centrifuged at 200 g for 5 minutes at room temperature (RT), washed with 30 ml cold RPMI, centrifuged for 5 minutes at 200×g at RT. Cells were then resuspended in cold RPMI + 9 mM MgCl2 at a concentration of 4 x 106cells / ml. Cells were kept on ice before seeding at 25 μL (0.1 x 105cells / well) into 96-well white OptiPlates (Revity).

[0303] Polypeptide constructs as disclosed herein were constructed as bivalent constructs with two C1q-binding domains (recited in Table 1) fused to a CD38 binding domain of SEQ ID NO: 56. Each polypeptide was diluted in Veronal buffer (VB) + 9 mM MgCl2and added to 13.3% (vol / vol) of normal human serum (NHS). The polypeptide constructs and serum (75 μL) were added to the cells to reach a final serum concentration of 10%, with construct dose typically ranging from 500-0.01 nM in 100 μL. As positive control for lysis, Digitonin (Promega, G9441) diluted to 0.13 mg / mL in CytoTox-Glo Assay buffer (Promega, G146) was further diluted to 0.4 mg / mL in VB + 9 mM MgCl2. 75 μL of Digitonin was added to cells, giving a final concentration of 0.03 mg / mL in 100 μL. Asnegative control for lysis, cells were incubated with 0 nM constructs in the respective serum conditions.

[0304] The plates were incubated for 1 hour at 37°C, 8% CO2with a brief mixing for 5 seconds at 700 rpm after the first 30 min. Plates were equilibrated to RT for 10 minutes before wells were added 40 μL of AAF-Glo™ Substrate (Promega, CytoTox-Glo Kit, G9292). The plates were then briefly mixed for 5 seconds at 700 rpm, incubated at RT for 15-30 minutes, and luminescence was measured. FIG. 2 shows the results from a CDC assay with the polypeptide constructs as disclosed herein with different affinities towards C1q as compared to a monovalent construct (C80). The affinity against C1q strongly influences the activity profile of the proteins in the CDC assay (FIG.2 - FIG.4). The bivalent polypeptide constructs as disclosed herein with two low affinity C1q domains for example PC513, PC518, or PC520 demonstrated less bell-shaped distribution with increased EC50 value as compared to the C80 control. Thus, the combination of the low affinity C1q domains and two complement factor-engaging domains broadens the activity profile of the polypeptide constructs i.e., EC50values get lower, and more activity is observed at high concentrations of the polypeptide constructs (less bell curve due to competitive inhibition). A small decrease in max lysis is observed when lowering the affinity against C1q. However, once the affinity towards C1q is very low the polypeptide construct can lose activity as demonstrated by PC517 and PC519 (FIG.2, TABLE 1). Table 1: C1q affinity of Exemplary polypeptide constructs ID Format C1q-binding C1q affinity domain (monovalent, nM) SEQ ID NO: C80 C1q-CD38 1 2.4 PC446 C1q-CD38- 1 2.4 C1q PC513 C1q-CD38- 3 191 C1q PC514 C1q-CD38- 4 - C1q PC515 C1q-CD38- 5 36.4 C1q PC516 C1q-CD38- 6 - C1q PC517 C1q-CD38- 7 NA C1qPC518 C1q-CD38- 9 1270 C1q PC519 C1q-CD38- 8 NA C1q PC520 C1q-CD38- 10 1300 C1q

[0305] Compared to the FDA-approved antibodies daratumumab and isatuximab, the exemplary polypeptide constructs (IDs: A, H and J) have increased cytotoxic activity on cells with low expression of CD38 (FIG.3- FIG.4). Furthermore, they show higher max lysis than HexaBody- CD38, a molecule optimized for complement activation (FIG.4)

[0306] To evaluate the ability of the exemplary polypeptide constructs to activate the complement system in the absence of a target (i.e., fluid phase complement activation), the polypeptide constructs were incubated in NHS at 37°C for 1 hour to facilitate complement activation and then the generation of complement C4a (C4a) was quantified using a commercial C4a ELISA. Exemplary polypeptide constructs were centrifuged for 10 minutes at 4°C to pellet potential aggregates and then diluted to 6666.67 nM in PBS. 7 microlitres (μL) of polypeptide constructs was mixed with 63 μL NHS (Complement Tech, Inc.) resulting in 666.67 nM of polypeptide construct in 90% serum. Buffer controls were made by adding 7 μL PBS to 63 μL NHS. Human heat aggregated IgG (HAG) was used as a positive control. The mixtures were incubated for 1 hour at 37°C and C4a concentrations (μg / ml) were measured in an ELISA according to the protocol provided by the manufacturer (MicroVue Complement C4a Fragment EIA , Quidel Cat. No. A036). As observed in FIG. 5A – FIG. 5B, the exemplary polypeptide constructs (IDs: C80, PC513, PC518, PC520) do not activate complement in the fluid phase as assessed by measuring generation of C4a. EXAMPLE 2. Generation and Evaluation of Fab-Based Polypeptide Constructs.

[0307] Polypeptide constructs having a first complement factor-engaging domain at the C- terminus of a heavy-chain (HC) of a CD38 binding Fab region of daratumumab having the heavy chain sequence of: EVQLLESGGGLVQPGGSLRLSCAVSGFTFNSFAMSWVRQAPGKGLEWVSAISGSGGGTYYADSVKGRFTISRDNSKNTLY LQMNSLRAEDTAVYFCAKDKILWFGEPVFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC (SEQ ID NO: 81);a light chain sequence of: EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASNRATGIPARFSGSGSGTDFTLTISSLEP EDFAVYYCQQRSNWPPTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQ ESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 82); and a second complement factor-engaging domain at the C-terminus of a light-chain (LC) of the daratumumab Fab region was designed in silico (FIG.1B). Several affinity variants of the polypeptide constructs comprising C1q complement factor-engaging domains as disclosed herein were tested in this format (Table 2). Linker length was also tested. Polypeptide constructs having C1q complement factor-engaging domain linked to the Fab region from Rituximab were also generated and tested in this format. Table 2: C1q affinity of Exemplary polypeptide constructs ID Format C1q-binding C1q affinity domain SEQ ID NO: C80 (control) C1q-CD38 1 High PC593-594 C1q-DaraFab- 10 Low 15GS-C1q PC439-442 C1q-DaraFab- 1 High 15GS-C1q PC440-443 C1q-DaraFab- 1 High 20GS-C1q

[0308] pcDNA3.1 plasmid encoding full length genes with an N-terminal IL-2 signal peptide and used to generate the polypeptide constructs as disclosed herein. The polypeptide constructs were expressed by transiently transfecting Expi293F cells at 3x106cells / ml, grown at 37°C, 8% CO2with shaking. The cells were transfected by adding a DNA (1:1 ratio of HC and LC) and PEI ‘Max’ mixture in Opti-MEM to the cells. Valproic acid, sodium propionate and glucose were added to the cells 16 hours post transfection to enhance expression. 6 days post transfection, the cells were pelleted by centrifugation and the supernatant was subjected to batch binding using recombinant protein A resin while mixing for 1 hour at 4°C. The resin was filtered from the supernatant by gravity flow and washed twice in 20 ml PBS. The polypeptide constructs were eluted with 50 mM glycine pH 2.7 and the eluent was pH adjusted by addition of 1 M Tris-HCl pH 8.0 to obtain a final concentration of 100 mM. The eluted constructs were concentrated and loaded on a 24 mL Superdex 200 Increase 10 / 300 GL columnequilibrated in PBS. The eluted polypeptide constructs were analyzed by SDS-PAGE and Fab containing constructs were pooled.

[0309] The polypeptide constructs were evaluated in CDC assays as described in Example 1. Additionally, in separate experiments polypeptide constructs were evaluated using normal rat serum (NRS, Complement Technology Inc) or C1q depleted NHS (Complement Technology, Inc. Catalog # A300) + 80 μg / ml rat C1q (Complement Technology, Inc. Catalog # R099). For NHS and C1q depleted NHS + rat C1q treated cells, plates were equilibrated to RT for 10 minutes before wells were added 40 μL of AAF-Glo™ Substrate (Promega, CytoTox-Glo Kit, G9292). The plates were briefly mixed for 5 seconds at 700 rpm, incubated for 15-30 minutes at RT, and luminescence was measured. For NRS treated cells, plates were equilibrated to RT for 10 minutes before 20 mL of alamarBlue™ HS Cell Viability Reagent (ThermoFisher, A50101) were added to the wells. The plates were briefly mixed for 5 seconds at 700 rpm, incubated for 2 hours at 37°C, 8% CO2, with brief mixing at for 5 seconds at 700 rpm every 30 min. After incubation, fluorescence was measured.

[0310] An exemplary polypeptide constructs against CD38, with a first complement factor- engaging domain fused to the C-terminus of the LC of the Fab region of daratumumab, and a second complement factor-engaging domain fused to the C-terminus of the HC of the Fab region of daratumumab (A-Fab) induced potent complement mediated killing of cells with low expression of CD38 (WSU-DLCL2 cells) when using NHS (FIG. 7). WSU-DLCL2 cells are resistant to complement mediated killing by FDA-approved antibodies, daratumumab and isatuximab. Furthermore, A-Fab also demonstrated a higher max lysis than HexaBody-CD38 (a molecule optimized for complement activation), or the FDA-approved antibodies (FIG.8).

[0311] Various linker lengths between the Fab region and the C1q complement factor- engaging domains were assessed. Linker lengths comprising 15 (“PC439-442”) and 20 (“PC440-443”) amino acids between the Fab region and C1q complement factor-engaging domains were evaluated in CDC assays with NHS and compared to the exemplary polypeptide construct A. Both PC439-442, and C-Fab can activate and induce complement mediated lysis of WSU cells (FIG. 9). Lowering the affinity broadens the activity profile of the polypeptide constructs disclosed herein i.e., as EC50values get lower, the more activity is observed at high concentrations of BICE (Comparing PC439-442 with high C1q affinity in FIG.9 with A-Fab with low C1q affinity in FIG.7).

[0312] A polypeptide construct comprising a Fab region against CD20 was also generated. One C1q complement factor-engaging domain (SEQ ID NO: 10) was fused to the C-terminus of the light chain of the Fab region of rituximab having a heavy chain sequence of: QVQLQQPGAELVKPGASVKMSCKASGYTFTSYNMHWVKQTPGRGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAYMQLSSLTSEDSAVYYCARSTYYGGDWYFNVWGAGTTVTVSAASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTV SWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC (SEQ ID NO: 83); a light chain sequence of: QIVLSQSPAILSASPGEKVTMTCRASSSVSYIHWFQQKPGSSPKPWIYATSNLASGVPVRFSGSGSGTSYSLTISRVEAE DAATYYCQQWTSNPPTFGGGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQE SVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 84); and a second complement factor-engaging domain (SEQ ID NO: 10) was fused to the C-terminus of the heavy-chain of rituximab (“PC589-592”) was generated and evaluated in a CDC assay with NHS. As seen FIG. 10, PC589-592 induced potent complement mediated killing of cells that expresses CD20.

[0313] Lastly, the polypeptide constructs were tested in a fluid phase complement activation assay to evaluate any complement activation in the absence of a target. As shown in FIG.11A – FIG. 11B, the tested polypeptide constructs, A-Fab and PC439-442, do not activate complement in the fluid phase as assessed by measuring generation of C4a. EXAMPLE 3. Generation and Evaluation of Fc Based Polypeptide Constructs.

[0314] Polypeptide constructs having a hIgG1 Fc-fragment of SEQ ID NO: 85 (CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQ VYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK) fused to a C1q complement factor- engaging domain (recited in Table 3) and a CD38 binding domain (SEQ ID NO: 56) at the N-terminus or C-terminus were designed in silico (FIG.12). Several C1q-binding affinity variants were tested in these formats. Fc point mutation variants with a K322A mutation were also generated in the polypeptide constructs disclosed herein. Additionally, the following CD38-binding domains were utilized in this example: QVQLQESGGGLVQAGGSLRLSCTGSGRTFRNYPMAWFRQAPGKEREFVAGITWVGASTLY ADFAKGRFTISRDNAKNTVYLQMNSLKPEDTAVYSCAAGRGIVAGRIPAEYADWGQGTQV TVSS (SEQ ID NO: 56), DVQLVESGGGLVQPGGSLRLSCSAEGFTLDDEIMSWVRQAPGKGREWVSTIWNYRSKTYY ADSVKGRFTISTDSAKNTMYLQIDSLKSEDTAVYYCARRRWGRAVVGGVDDEYDYWGQG TQVTVSS (SEQ ID NO: 86),DVQLVESGGGLVQPGGSLRLSCAASGFTLDYYAIGWFRQAPGKEREGVSCITSSGRSTSYA DSVKGRFTVSRDNAKNTVYLQMNSLKPEDTAIYYCAADRTFHGNYCSGQYDYWGQGTQV TVSS (SEQ ID NO: 87). Table 3: C1q affinity of Exemplary polypeptide constructs ID Format C1q- CD38- C1q C1q binding binding affinity affinity domain domain (human) (rat) SEQ ID SEQ ID NO: NO: PC809 CD38-15GS-hIgG1Fc- 1 54 High Low 15GS-C1q PC810 CD38-15GS- 1 54 High Low hIgG1Fc(K332A)-15GS- C1q PC656 CD38-15GS-hIgG1Fc- 1 86 High Low 15GS-C1q PC657 CD38-15GS- 1 86 High Low hIgG1Fc(K332A)-15GS- C1q PC649 C1q-15GS- 1 54 High Low hIgG1Fc(K332A)-CD38 PC651 C1q-15GS- 1 87 High Low hIgG1Fc(K332A)-CD38 PC615 C1q-15GS-hIgG1Fc- 10 87 Low NA 15GS-CD38-His PC653 C1q-hIgG1Fc(K332A)- 1 86 High Low 15GS-C1q PC655 CD38-15GS- 1 87 High Low hIgG1Fc(K332A)-15GS- C1q PC614 C1q-15GS-hIgG1Fc- 10 86 Low NA 15GS-CD38 PC617 CD38-10GS-hIgG1Fc- 10 54 Low NA 20GS-C1q PC723 C1q-15GS- 10 87 Low NA hIgG1Fc(K332A,K439E)- 15GS-CD38 PC610 C1q-15GS-hIgG1Fc- 1 54 High Low 15GS-CD38

[0315] pcDNA3.1 plasmid encoding full length genes with an N-terminal IL-2 signal peptide and expressed and purified as described in Example 2.

[0316] Complement activation was evaluated in CDC assays using different exemplary polypeptide constructs comprising Fc domains. As observed in FIG. 13 and FIG.14A – FIG.14B,polypeptide constructs with different C1q complement factor-engaging domains fused at the N- terminus of hIgG1 and a C1q complement factor-engaging domain fused in the C-terminus induces potent complement activation (“PC809”). A K322A mutation, that abrogates C1q binding to hIgG1, has no effect on the polypeptide constructs activity (“PC810,” “PC656,” “PC657”).

[0317] In other experiments, polypeptide constructs comprising Fc domains with a C1q complement factor-engaging domain fused at the N-terminus of hIgG1 and different CD38 antigen- binding moieties fused in the C-terminus were tested for complement activation (“PC649,” “PC651,” “PC653,” and “PC615”). As seen in FIG. 15 and FIG.16, these polypeptide constructs comprising Fc domains induces complement mediated killing of cancer cells that expresses CD38.

[0318] The polypeptide constructs comprising Fc domains were also evaluated a fluid phase complement activation assay as described in Example 2. As demonstrated in FIG.17, the polypeptide constructs with a high affinity C1q complement factor-engaging domain were fused at the N-terminus of hIgG1 and a CD38 antigen-binding moiety was fused at the C-terminus induces complement activation in the fluid phase.

[0319] In contrast, polypeptide constructs comprising Fc domains with a low affinity C1q complement factor-engaging domain fused at the N-terminus of hIgG1 and a CD38 antigen-binding moiety fused at the N-term does not induce complement activation in the fluid phase (FIG. 18). Moreover, the polypeptide constructs comprising Fc domains with a high (“PC653” or “PC655”) or low (“PC615,” “PC614,” or “PC617”) affinity C1q complement factor-engaging domain fused at the C-terminus of hIgG1 and a CD38 antigen-binding moiety fused at the N-term does not induces complement activation in the fluid phase (FIG.17 and FIG.18A - FIG.18B).

[0320] Finally, the effect of K322A and K438E mutations in a polypeptide construct comprising an Fc domain based on hIgG1 were evaluated in a fluid phase complement activations assay. As observed in FIG.18A - FIG.18B, the polypeptide construct comprising Fc domains with a low affinity C1q complement factor-engaging domain fused at the N-terminus of hIgG1, with K322A and K438E mutations, and a CD38 antigen-binding moiety fused at the C-terminus (PC617) does not induce complement activation in the fluid phase. PC617 also has increased cytotoxicity as compared to a polypeptide construct without Fc region (FIG. 31A – FIG.31B). Furthermore, the polypeptide constructs with an N-terminal C1q complement factor-engaging domain (PC614 and PC617) activate complement in fluid phase while C-terminal fusion does not result in fluid phase activation (FIG.33A – FIG.33D).

[0321] Polypeptide constructs (PC80, and PC439-442) were compared to a polypeptide construct with increased affinity towards rat C1q (“PC610”) with a long half-life was tested in CDCassays using human C1q depleted serum. A, PC439-442 and PC610 all demonstrated high CDC activity with increased cytotoxicity in PC439-442, and PC610 (FIG.32). EXAMPLE 4. Generation and evaluation of IgG based bispecific complement engagers.

[0322] Polypeptide constructs with a C1q complement factor-engaging domain at the C- terminus of the heavy-chain (HC) of an IgG region of daratumumab (SEQ ID NO: 48) was designed in silico to be combined with the light chain on daratumumab (SEQ ID NO: 49) (“PC90-597”). A different polypeptide construct with a C1q complement factor-engaging domain at the C-terminus of the light-chain (LC) of the IgG region of daratumumab (SEQ ID NO: 49) was designed in silico to be combined with the heavy chain of daratumumab (SEQ ID NO: 48) (“PC91-594”) (FIG.20 and FIG. 30). Additionally, IgG-based bispecific complement engagers were also designed based on fusing cetuximab Hc (SEQ ID NO: 44), cetuximab Lc (SEQ ID NO: 45), trastuzumab Hc (SEQ ID NO: 46) or trastuzumab Lc (SEQ ID NO: 47) to C1q complement factor-engaging domains in the same manner to target EFGR (“PC686-687”) and Her2 (“PC910-911”), respectively. Several affinity variants of C1q complement factor-engaging domain were tested in these formats (Table 4). Table 4: C1q affinity of Exemplary polypeptide constructs ID Format C1q-binding C1q affinity C1q affinity domain (human) (rat) SEQ ID NO: PC90-597 Dara-Lc Dara-Hc- 10 Low NA 15GS-C1q PC91-594 Dara-Hc Dara-Lc- 10 Low NA 15GS-C1q PC90-671 Dara-Lc Dara-Hc 10 Low NA (K332A) -15GS- C1q PC90-647 Dara-Hc (K332) N / A Very Low Very Low DaraLc PC91-442 Dara-Hc 1 High Low Dara-Lc-15GS- C1q PC442-647 Dara-Hc(K332A) 1 High Low Dara-Lc-15GS- C1q PC90-823 Dara_FullHc- 1 High Low 15GS-C1q Dara_LCPC90-646 Dara_FullHc 1 Very Low Very Low (K332A)-15GS- C1q Dara_LC PC90-857 Dara_Lc 88 High Low Dara_FullHc-C1q PC90-858 Dara_Lc 88 High Low Dara_FullHc (K332A)-C1q PC90-889 Dara_Lc 10 Low NA Dara_FullHc- 15GS-C1q PC90-890 Dara_Lc 9 Medium NA Dara_FullHc- 15GS-C1q PC891-892 Dara_Lc 10 Very low NA (mmIgG2a) Dara_FullHc (mmIgG2a)-15GS- C1q PC686-687 Cetuximab-Lc 10 Low NA Cetuximab-Hc- 15GS-C1q PC910-911 Trastuzumab Lc 10 Low NA (mmIgG2a) Trastuzumab HC(mmIgG2a) - 15GS-C1q

[0323] pcDNA3.1 plasmid encoding full length genes with an N-terminal IL-2 signal peptide were expressed and purified as described in Example 2.

[0324] Complement activation was evaluated in CDC assays using different IgG-BiCEs. As observed in FIG.21, PC90-597, a polypeptide construct based on daratumumab with a low affinity C1q complement factor-engaging domain fused to the C-terminus of the heavy chain of hIgG1 induced complement activation. PC91-594, a polypeptide construct based on daratumumab with a low affinity C1q complement factor-engaging domain fused to the C-terminus of the light chain of hIgG1 induced complement activation on cells WSU-DLCL2 cells expression CD38 (FIG.21).

[0325] To evaluate if the endogenous binding site for C1q in hIgG1 affects the activity of the polypeptide constructs comprising the IgG region, the K322A mutation was introduced into different polypeptide constructs (“PC90-671” and “PC90-647”) and their activity were evaluated in CDC assays. As observed in FIG. 22, introductions of the K322A mutation in an...

Claims

CLAIMS 1. A polypeptide construct comprising: (a) a first complement factor-engaging domain; (b) an antigen-binding moiety that binds to a target protein; and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety; and wherein: (i) the first complement factor-engaging domain binds to a C1q complement factor; (ii) the first complement factor-engaging domain comprises a single variable domain of a heavy chain antibody (VHH domain); (iii) the target protein is a cluster of differentiation 38 (CD38), and the antigen- binding moiety binds to or modulates CD38; (iv) the antigen-binding moiety binds to or modulates an inflammation marker, and wherein the antigen-binding moiety that binds to the inflammation marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof; and / or (v) the antigen-binding moiety binds to or modulates an autoimmune marker, and wherein the antigen-binding moiety that binds to the autoimmune marker is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen- binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof.

2. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain and / or the second complement factor-engaging domain modulates an activity of the complement system.

3. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain and / or the second complement factor-engaging domain: (a) directly activates human complement system; or (b) indirectly activates human complement system.

4. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain: (a) directly binds C1q complement factor; or (b) does not directly bind C1q complement factor.

5. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain and / or the second complement factor-engaging domain have a lower affinity for complement factor as compared to an affinity of the antigen-binding moiety to the target protein.

6. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain and / or the second complement factor-engaging domain comprises a C1q complement factor- engaging domain.

7. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain and / or the second complement factor-engaging domain comprises a single variable domain of a heavy chain antibody (VHH domain); optionally wherein the VHH domain binds to C1q complement factor; optionally wherein the VHH domain binds to a C1q complement factor with a KDof about 100 nM to about 2 mM.

8. The polypeptide construct of claim 1, wherein the antigen-binding moiety is selected from the group consisting of a single domain antibody, a heavy-chain only antibody (HCAb), a single chain antigen-binding fragment (ScFab), a fragment antigen-binding (Fab) domain, an antigen-binding moiety comprising a fragment crystallizable (Fc) domain, a single chain variable fragment, a minibody, an antibody, and any combination thereof.

9. The polypeptide construct of claim 1, wherein the antigen-binding moiety is linked to the first complement factor-engaging domain and the second complement factor-engaging domain with a linker sequence; optionally wherein the linker sequence comprises from about 5 amino acids to about 30 amino acids; optionally wherein the linker sequence comprises from about 15 amino acids to about 20 amino acids.

10. The polypeptide construct of claim 1, wherein the target protein is implicated in a disease; optionally wherein the disease is a cancer, an autoimmune disease, an inflammatory disease, or a neurological disease.

11. The polypeptide construct of claim 1, wherein the target protein is expressed on a surface of a cell, optionally wherein the cell is: (a) a cancer cell, optionally wherein the cancer cell is a carcinoma cell, a breast cancer cell, an ovarian cancer cell, a gastric cancer cell, or a colon cancer cell; (b) an immune cell, optionally wherein the immune cell is a natural killer (NK) cell, a macrophage, a monocyte, a neutrophil, a dendritic cell, a T cell, a B cell, a mast cell, a basophil, or an eosinophil; (c) an endothelial cell; (d) an epithelial cell; or (e) a microbial cell.

12. The polypeptide construct of claim 1, wherein the antigen-binding moiety binds to a cancer- specific marker, an immune-specific marker, a pathogen-specific marker, a tissue-specific marker, or an organ-specific marker; optionally wherein: (a) the target protein is EGFR, CD38, CD19, CD20, CD55, CD59, CD7, HER2, EGFR, EpCAM, or FOLR1; (b) the autoimmune marker is a target protein is implicated in multiple sclerosis, psoriasis, psoriatic arthritis, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, Sjogren's syndrome, Behcet's disease, ulcerative colitis, or Guillain-Barre syndrome; and / or(c) the inflammation marker is selected from the group consisting of IL-6, CRP, TNF, IL-10, IL-17, IGN-gamma, eotaxin, IP-10, MCP-1, and MIG.

13. The polypeptide construct of claim 1, wherein the antigen-binding moiety comprises a Fab or an IgG region, and wherein the first complement factor-engaging domain or the second complement factor-engaging domain is linked to a C-terminus of a light chain in the Fab or the IgG region.

14. The polypeptide construct of claim 1, wherein the antigen-binding moiety comprises a Fab, an Fc, or an IgG region, and wherein the first complement factor-engaging domain or the second complement factor-engaging domain is linked to a C-terminus of a heavy chain in the Fab, the Fc, or the IgG region.

15. The polypeptide construct of claim 1, wherein the first complement factor-engaging domain or the second complement factor-engaging domain have a lower affinity for a complement factor as compared to an affinity of the antigen-binding moiety to the inflammation marker or the autoimmune marker.

16. The polypeptide construct of claim 1, wherein polypeptide construct has: (a) higher max cytotoxicity than daratumumab, isatuximab, or HexaBody-CD38, as measured by CDC assay; and / or (b) higher max lysis than daratumumab, isatuximab, or HexaBody-CD38, as measured by CDC assay.

17. The polypeptide construct of claim 1, further comprising an albumin-binding Nb; optionally wherein: (a) the albumin-binding Nb is linked to a N-terminus of the first complement factor- engaging domain or a N-terminus of the second complement factor-engaging domain; and / or (b) the albumin-binding Nb is linked to a C-terminus of a light chain or a C- terminus of a heavy chain in the Fab.

18. The polypeptide construct of claim 17, wherein the polypeptide construct comprising the albumin-binding Nb has increased half-life as compared to a polypeptide construct that lacks the albumin-binding Nb.

19. The polypeptide construct of claim 1, wherein the antigen-binding moiety comprises a Fc region, wherein the Fc region comprises one or more amino acid modification(s) with respect to a wildtype Fc region that improves serum half-life as compared to the wildtype Fc region; optionally wherein: (a) the one or more amino acid modification(s) is selected from the group consisting of M252Y, S254T, T256E, M428L, N434S, T256D, T307R, Q311V, N315D, N286D, T307R, H285N, and T307Q; or (b) the modified Fc region comprises a set of amino acid modifications selected from the group consisting of M252Y / S254T / T256E, M428L / N434S, T256D / T307R / Q311V, T256D / N315D / A378V, T256D / N286D / T307R / Q311V, H285N / T307Q / N315D, T256D / T307R / Q311V / A378V, H285D / Q311V / A378V, T256D / H285D / A378V, T256D / Q311V / A378V, T256D / H285D / N286D / T307R / A378V, T256D / H286D / T307R / Q311V / A378V, T307Q / Q311V / A378V, H285D / T307Q / A378V, and T256D / H285D / T307R / Q311V / A378V.

20. The polypeptide construct of claim 1, wherein the polypeptide construct: (a) induces complement activation in the fluid phase as assessed by measuring generation of C4a; or (b) does not induce complement activation in the fluid phase as assessed by measuring generation of C4a.

21. The polypeptide construct of claim 1, wherein the polypeptide construct comprises an IgG region comprising: (a) a Fab region having the sequence of any one of SEQ ID NO: 40 to SEQ ID NO: 78; and / or(b) an IgG region comprising the sequence of any one of SEQ ID NO: 40 to SEQ ID NO:

78.

22. A polypeptide construct comprising: (a) a first complement factor-engaging domain that binds to a C1q complement factor; (b) an antigen-binding moiety that binds to a cancer-specific marker, and wherein the cancer-specific marker is CD38, EGFR, CD19, CD20, CD55, CD59, CD7, HER2, EpCAM, or FOLR1; and (c) a second complement factor-engaging domain that binds to the C1q complement factor, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the antigen-binding moiety.

23. A pharmaceutical composition that comprises the polypeptide construct of any one of claims 1-22, and a pharmaceutically acceptable carrier or diluent.

24. The polypeptide construct of any one of claims 1-22, or the pharmaceutical composition of claim 23, for use in treating a disease in a subject in need thereof.

25. The polypeptide construct of any one of claims 1-22, or the pharmaceutical composition of claim 23, for use in inducing complement-mediated cell death of a target cell that expresses a disease-specific marker; wherein contacting of the polypeptide construct or the pharmaceutical composition with the target cell that expresses the disease-specific marker results in complement-mediated cell death of the target cell that expresses the disease-specific marker.

26. The polypeptide construct of any one of claims 1-22, or the pharmaceutical composition of claim 23, for use in a method of treating a disease in a subject in need thereof, the method comprising: contacting a cell that expresses a target protein implicated in the disease or condition with the polypeptide construct of any one of claims 1-22, or the pharmaceuticalcomposition of claim 23; wherein the contacting results in complement-mediated cell death of the cell that expresses the target protein.

27. A polypeptide construct for use in a method of reducing side-effects associated with an IgG antibody-based therapy, wherein the polypeptide construct comprises: (a) a first complement factor-engaging domain; (b) an IgG region that comprises a light chain and a heavy chain, wherein the IgG region comprises an antigen binding fragment (Fab) the binds to a target protein; and (c) a second complement factor-engaging domain, wherein the first complement factor-engaging domain and the second complement factor-engaging domain are linked to the IgG region that binds CD38, wherein the administering results in reduction of one or more side effects as compared to the administering a comparable amount of the IgG antibody-based therapy; optionally wherein: (i) the polypeptide construct is a polypeptide construct of any one of claims 1 to 21; and / or (ii) the one or more side effects comprises allergic reactions such as hives or itching, nausea, vomiting, fatigue, fever, chills, malaise, skin rashes, low blood pressure, lethargy, or any combination thereof.

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