Displacers of IgE-FceRI
Disclosed are single domain antibody-based constructs, which are useful for treating IgE-related disorders or conditions by facilitating the dissociation of IgE from the high-affinity IgE receptor. Further disclosed are compositions comprising the constructs. Also nucleic acids and vectors are provides, as is methods of treatment of IgE related disorders.
1 . A multi-specific construct comprising
a. a first single domain antibody (sdAb) able to displace bound IgE from FcϵRI,
b. a second sdAb that binds to IgE,
c. a moiety that links the first and second sdAb,
wherein
the first and second sdAb bind non-identical epitopes of IgE, and
the multi-specific construct can displace bound IgE from the IgE high-affinity receptor (FcϵRI) with improved displacement activity compared to the first or second sdAb,
wherein the moiety that links the first and second sdAb comprises
an Fc region from an IgG antibody or from an Fc region comprising a mutation that induces heterodimerisation, and the first sdAb and second sdAb are fused or coupled covalently to the C-terminal end of a first Fc region polypeptide and a second Fc region polypeptide, respectively,
wherein the first sdAb comprises a first CDR1, CDR2, and CDR3 binding regions each comprising or consisting of an amino acid sequence in the amino acid sequence set forth in SEQ ID NO: 1, wherein the amino acid sequence of the first CDR1, CDR2, and CDR3 binding regions are determined according to a single numbering scheme, wherein said numbering scheme is either Kabat, Chothia, IMTG or Aho numbering scheme, and
the second sdAb comprises a second CDR1, CDR2, and CDR3 binding regions each comprising or consisting of an amino acid sequence in the amino acid sequence set forth in SEQ ID NO: 9 or 25, wherein the amino acid sequence of the second CDR1, CDR2, and CDR3 binding regions are determined according to a single numbering scheme, wherein said numbering scheme is either Kabat, Chothia, IMTG or Aho numbering scheme.
2 . The multi-specific construct according to claim 1 , wherein the IgG antibody is selected from IgG1, IgG2, IgG3, and IgG4.
3 . The multi-specific construct according to claim 1 , wherein the Fc region is from a human Fc region.
4 . The multi-specific construct according to claim 3 , wherein when IgG is IgG4, the Fc region comprises a truncated IgG4 hinge region.
5 . The multi-specific construct according to claim 1 , wherein the first sdAb or the second sdAb or both sdAbs consist(s) of affinity-matured, human or humanized amino acid sequences in the non-CDR regions.
6 . The multi-specific construct according to claim 1 , wherein the multi-specific construct is modified to add or remove glycosylation sites.
7 . The multi-specific construct according to claim 1 , wherein the Fc-region is modified to increase serum half-life of the multi-specific construct, compared to natural Fc-region.
8 . The multi-specific construct according to claim 1 , wherein the first and second sdAb are fused or coupled to the moiety via a linker.
9 . The multi-specific construct according to claim 8 , wherein the linker is a G4S linker.
10 . The multi-specific construct according to claim 9 , wherein the mutation that induces heterodimerisation comprises mutations in each polypeptide of the IgG-Fc, wherein the first polypeptide comprises the mutations T349C, T366S, L368A, and Y407V, and the second polypeptide comprises the mutations S354C and T366W, wherein numbering is per the EU numbering index.
11 . The multi-specific construct according claim 10 , wherein when IgG is IgG4, the Fc regions comprise the mutation S228P in IgG4, wherein numbering is per the EU numbering index.
12 . A multi-specific construct comprising:
a. a first single domain antibody (sdAb) able to displace bound IgE from FcϵRI;
b. a second sdAb that binds to IgE; and
c. a Fc region,
wherein the multi-specific construct comprises two polypeptides having the respective SEQ ID NOs: 94 and 102 or SEQ ID NOs: 94 and 338, wherein non-CDR regions of at least one of said polypeptides are modified to comprise human or humanized amino acid sequences; and wherein the multi-specific construct is able to displace bound IgE from FcϵRI with improved displacement activity compared to the first or second sdAb.