CD16A binding proteins and use for the treatment of immune disorders
CD16A binding proteins useful for the reduction of a deleterious immune response are described. In one aspect, humanized anti-cd16A antibodies, optionally lacking effector function, are used for the treatment of immune disorders such as idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia.
1. An isolated anti-CD16A antibody or antigen binding fragment thereof comprising a V H CDR1 having the sequence of SEQ ID NO:35, a V H CDR2 having the sequence of SEQ ID NO:39, a V H CDR3 having the sequence of SEQ ID NO:59, a V L CDR1 having the sequence of SEQ ID NO:67, a V L CDR2 having the sequence of SEQ ID NO:75, and a V L CDR3 having the sequence of SEQ ID NO:88, wherein at least one of said CDRs has one or more amino acid modifications selected from the group consisting of, in the V H domain, a Val at position 34 in CDR1; a Leu at position 50 in CDR2; a Phe at position 52 in CDR2; an Asn at position 54 in CDR2; a Ser at position 60 in CDR2; a Ser at position 62 in CDR2; a Tyr at position 99 in CDR3; an Asp at position 101 of CDR3; and, in the V L domain, an Arg at position 24 in CDR1; a Ser at position 25 in CDR1; a Tyr at position 32 in CDR1; a Leu at position 33 in CDR1; an Ala at position 34 in CDR1; an Asp, Trp or Ser at position 50 in CDR2; an Ala at position 51 in CDR2; a Ser at position 53 in CDR2; an Ala or Gln at position 55 in CDR2; a Thr at position 56 in CDR2; a Tyr at position 92 in CDR3; a Ser at position 93 in CDR3; and a Thr at position 94 in CDR3, and wherein said positions are according to Kabat.
2. A humanized anti CD16A antibody comprising a human Fc region modified relative to a naturally occurring human Fc region, which modified Fc region does not bind any Fc receptor and does not bind the C1q component of complement, wherein said antibody comprises a V H CDR1 having the sequence of SEQ ID NO:35, a V H CDR2 having the sequence of SEQ ID NO:39, a V H CDR3 having the sequence of SEQ ID NO:59, a V L CDR1 having the sequence of SEQ ID NO:67, a V L CDR2 having the sequence of SEQ ID NO:75, and a V L CDR3 having the sequence of SEQ ID NO:88; and
wherein said antibody comprises a V L domain having a FR1 domain having the amino acid sequence of SEQ ID NO:66, a FR2 domain having the amino acid sequence of SEQ ID NO:74, a FR3 domain having the amino acid sequence of SEQ ID NO:87, and a FR4 domain having the amino acid sequence of SEQ ID NO:94.
3. The antibody of claim 1 or 2 , wherein said antibody comprises an Fc region that is a human IgG heavy chain.
4. The antibody of claim 1 , wherein said antibody does not bind an Fc receptor and does not bind the C1q component of complement.
5. The antibody of claim 2 or 4 , wherein said antibody comprises an Fc region that is not glycosylated.
6. The antibody of claim 5 , wherein the amino acid residue at position 297 of the Fc region is not glycosylated and wherein said position is according to Kabat.
7. The antibody of claim 5 , wherein the amino acid residue at position 297 of the Fc region is not asparagine and wherein said position is according to Kabat.
8. The antibody of claim 1 , wherein the antibody is a humanized antibody.
9. The antibody of claim 1 , wherein the antibody inhibits CD16A binding by the variable domain of 3G8, said variable domain comprising a V H domain comprising SEQ ID NO: 2 and a V L domain comprising SEQ ID NO: 4.
10. The antibody of claim 1 , which antibody is a single chain antibody.
11. The antibody of claim 1 , which antibody is a tetrameric antibody.
12. The antibody of claim 1 , wherein said antibody comprises a V H domain having the amino acid sequence of SEQ ID NO:113.
13. The antibody of claim 1 , wherein said antibody comprises a V L domain having the amino acid sequence of SEQ ID NO:96, SEQ ID NO:100, or SEQ ID NO:98.
14. The antibody of claim 12 , wherein said antibody further comprises a V L domain having the amino acid sequence of SEQ ID NO:96, 98, 100, or 118.
15. The antibody of claim 8 , wherein said antibody comprises a V L domain having a FR1 domain having the amino acid sequence of SEQ ID NO:66, a FR2 domain having the amino acid sequence of SEQ ID NO:74, a FR3 domain having the amino acid sequence of SEQ ID NO:87, and a FR4 domain having the amino acid sequence of SEQ ID NO:94.
16. The antibody of claim 8 further comprising a V H domain having a FR1 domain having the amino acid sequence of SEQ ID NO:31, a FR2 domain having the amino acid sequence of SEQ ID NO:38, a FR3 domain having the amino acid sequence of SEQ ID NO:51, and a FR4 domain having the amino acid sequence of SEQ ID NO:64.
17. A humanized anti CD16A antibody comprising a human Fc region modified relative to a naturally occurring human Fc region, which modified Fc region does not bind an Fc receptor and does not bind the C1q component of complement, wherein said antibody comprises a V H CDR1 having the sequence of SEQ ID NO:35, a V H CDR2 having the sequence of SEQ ID NO:39, a V H CDR3 having the sequence of SEQ ID NO:59, a V L CDR1 having the sequence of SEQ ID NO:67, a V L CDR2 having the sequence of SEQ ID NO:75, and a V L CDR3 having the sequence of SEQ ID NO:88; and
wherein said antibody further comprises a V H domain having a FR1 domain having the amino acid sequence of SEQ ID NO:31, a FR2 domain having the amino acid sequence of SEQ ID NO:38, a FR3 domain having the amino acid sequence of SEQ ID NO:51, and a FR4 domain having the amino acid sequence of SEQ ID NO:64.
18. The antibody of claim 2 , 17 , or 8 comprising a V H FR3 domain, wherein said domain comprises one amino acid substitution that is Gln at residue 94, and wherein said position is according to Kabat.
19. The antibody of claim 1 , which antibody is a Fab, Fab′, F(ab′) 2 or a Fv fragment.