Immunoglobulin variable domains
VH domain, in which: (i) the amino acid residue at position 112 is one of K or Q; and/or (ii) the amino acid residue at position 89 is T; and/or (iii) the amino acid residue at position 89 is L and the amino acid residue at position 110 is one of K or Q; and (iv) in each of cases (i) to (iii), the amino acid at position 11 is preferably V; and in which said VH domain contains a C-terminal extension (X)n, in which n is 1 to 10, preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or 2, such as 1); and each X is an (preferably naturally occurring) amino acid residue that is independently chosen, and preferably independently chosen from the group consisting of alanine (A), glycine (G), valine (V), leucine (L) or isoleucine (I).
1. A method of modifying an immunoglobulin single variable domain (VH or VHH) to have reduced binding by pre-existing antibodies found in human blood or serum, the method comprising mutating the amino acid sequence of the immunoglobulin single variable domain to generate a modified immunoglobulin single variable domain comprising the amino acid V at position 11 and the amino acid L at position 89, wherein the positions are numbered according to Kabat numbering; wherein, prior to mutation, the immunoglobulin single variable domain comprises:
(i) an amino acid other than V at position 11 and an amino acid other than L at position 89;
(ii) an amino acid V at position 11 and an amino acid other than L at position 89; or
(iii) an amino acid other than V at position 11 and an amino acid L at position 89.
2. The method of claim 1 , wherein the modified immunoglobulin single variable domain comprises an amino acid K or Q at position 110 according to Kabat numbering.
3. The method of claim 2 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
4. The method of claim 2 , wherein the modified immunoglobulin single variable domain comprises an amino acid K or Q at position 112 according to Kabat numbering.
5. The method of claim 4 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
6. The method of claim 1 , wherein the modified immunoglobulin single variable domain comprises an amino acid K or Q at position 112 according to Kabat numbering.
7. The method of claim 6 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
8. The method of claim 1 , wherein the modified immunoglobulin single variable domain comprises an amino acid A or P at position 14 according to Kabat numbering.
9. The method of claim 1 , wherein the modified immunoglobulin single variable domain comprises an amino acid A or P at position 41 according to Kabat numbering.
10. The method of claim 1 , wherein the modified immunoglobulin single variable domain comprises an amino acid Q or L at position 108 according to Kabat numbering.
11. The method of claim 1 , wherein the immunoglobulin single variable domain is comprised in a protein, polypeptide or other construct.
12. The method of claim 1 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
13. A method of modifying an immunoglobulin single variable domain (VH or VHH) having an amino acid other than K or Q at position 112 to have reduced binding by pre-existing antibodies found in human blood or serum, the method comprising mutating the amino acid at position 112 to K or Q, wherein the positions are numbered according to Kabat numbering, optionally wherein the modified immunoglobulin single variable domain comprises an amino acid Q or L at position 108 according to Kabat numbering.
14. The method of claim 13 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
15. The method of claim 13 , wherein the modified immunoglobulin single variable domain comprises an amino acid K or Q at position 110 according to Kabat numbering.
16. The method of claim 15 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.
17. The method of claim 13 , wherein the modified immunoglobulin single variable domain comprises an amino acid L, V, or K at position 11 according to Kabat numbering.
18. The method of claim 13 , wherein the modified immunoglobulin single variable domain comprises an amino acid A or P at position 14 according to Kabat numbering.
19. The method of claim 13 , wherein the modified immunoglobulin single variable domain comprises an amino acid A or P at position 41 according to Kabat numbering.
20. The method of claim 13 , wherein the modified immunoglobulin single variable domain comprises an amino acid T, V, or L at position 89 according to Kabat numbering.
21. The method of claim 13 , wherein the immunoglobulin single variable domain is comprised in a protein, polypeptide or other construct.
22. A method of modifying an immunoglobulin single variable domain (VH or VHH) to have reduced binding to its C-terminal end by pre-existing antibodies found in human blood or serum, the method comprising mutating the amino acid sequence of the immunoglobulin single variable domain at position 11, at position 89, or at positions 11 and 89 to generate a modified immunoglobulin single variable domain comprising the amino acid V at position 11 and the amino acid L at position 89, wherein the positions are numbered according to Kabat numbering.
23. The method of claim 22 , further comprising extending the C-terminal end of said immunoglobulin single variable domain by 1 to 5 amino acid residues.