BMA031 antigen binding polypeptides

1. An antigen binding polypeptide comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein

(1) the VH comprises

(a) a heavy chain complementarity determining region 1 (HCDR1) comprising the amino acid sequence of SEQ ID NO: 52,

(b) a HCDR2 comprising the amino acid sequence of

YINPYNDVTKYX 1 X 2 KFX 3 G (SEQ IDNO: 53), wherein

X 1 is A;

X 2 is E; and

X 3 is Q;

wherein the tyrosine (Y) at position 53 of the HCDR2 is substituted with an arginine (R), wherein the 2 nd tyrosine (Y) from the N-terminus of SEQ ID NO: 53 is substituted with an arginine (R), and wherein the 2 nd tyrosine (Y) is at position 53 of the HCDR2 according to Kabat numbering,

(c) a HCDR3 comprising the amino acid sequence of SEQ ID NO: 64, and

(d) heavy chain framework regions (HFR)1-4;

(2) the VL comprises

(a) a light chain complementarity determining region 1 (LCDR1) comprising the amino acid sequence of SEQ ID NO: 54,

(b) a LCDR2 comprising the amino acid sequence of SEQ ID NO: 55,

(c) a LCDR3 comprising the amino acid sequence of SEQ ID NO: 74, and

(d) light chain framework regions (LFR)1-4;

wherein

(i) position 30 in HFR1 according to Kabat numbering is a threonine (T) or is substituted with a positively charged amino acid, and/or

(ii) position 90 in HFR3 according to Kabat numbering is substituted with a tyrosine Y residue,

and wherein the antigen binding polypeptide specifically binds to an α/β T cell receptor (TCR)/CD3 complex.

2. The antigen binding polypeptide according to claim 1 , wherein

the positively charged amino acid in the heavy chain

at position 30 is R, K or H.

3. The antigen binding polypeptide according to claim 1 , wherein the VH and VL form a first binding site, and wherein the antigen binding polypeptide comprises a second antigen binding site.

4. The antigen binding polypeptide according to claim 1 , wherein threonine (T) at position 30 in the heavy chain is substituted with asparagine (N) or serine (S).

5. A nucleic acid or set of nucleic acids coding for an antigen binding polypeptide according to claim 1 or a nucleic acid vector comprising said nucleic acid.

6. A recombinant host cell comprising the vector according to claim 5 , wherein said host cell is

(i) a lymphocyte, optionally a T lymphocyte or T lymphocyte progenitor cell, or a CD4 or CD8 positive T cell; or

(ii) a cell for recombinant expression, such as a Chinese Hamster Ovary (CHO) cell or a yeast cell.

7. A pharmaceutical composition comprising the antigen polypeptide according to claim 1 , a pharmaceutically acceptable carrier, diluent stabilizer, and/or excipient.

8. A method of producing the antigen binding polypeptide according to claim 1 , comprising

(i) providing a suitable host cell,

(ii) providing a genetic construct comprising a coding sequence encoding the antigen binding polypeptide,

(iii) introducing said genetic construct into said suitable host cell, and

(iv) expressing said genetic construct by said suitable host cell.

9. A method for improving or maintaining the binding and/or improving the stability of an antigen binding polypeptide comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein

(1) the VH comprises

(a) a heavy chain complementarity determining region 1 (HCDR1) comprising the amino acid sequence of SEQ ID NO: 52 (SYVMH),

(b) a HCDR2 comprising the amino acid sequence of

YINPYNDVTKYX 1 X 2 KFX 3 G (SEQ ID NO: 53), wherein

X 1 is A;

X 2 is E; and

X 3 is Q;

wherein the tyrosine (Y) at position 53 of the HCDR2 is substituted with an arginine (R), wherein the 2 nd tyrosine (Y) from the N-terminus of SEQ ID NO: 53 is substituted with an arginine (R), and wherein the 2 nd tyrosine (Y) is at position 53 of the HCDR2 according to Kabat numbering,

(c) a HCDR3 comprising the amino acid sequence of SEQ ID NO: 64, and

(d) heavy chain framework regions (HFR)1-4;

(2) the VL comprises

(a) a light chain complementarity determining region 1 (LCDR1) comprising the amino acid sequence of SEQ ID NO: 54 (SATSSVSYMH),

(b) a LCDR2 comprising the amino acid sequence of SEQ ID NO: 55 (DTSKLAS),

(c) a LCDR3 comprising the amino acid sequence of SEQ ID NO: 74, and

(d) light chain frameworks (LCR)1-4;

wherein

(i) position 30 in HFR1 according to Kabat numbering is a threonine (T) or is substituted with a positively charged amino acid, and/or

(ii) position 90 in HFR3 according to Kabat numbering is substituted with a tyrosine (Y) residue,

wherein

(1) the binding of the antigen binding polypeptide to an α/β T cell receptor (TCR)/CD3 complex is increased compared to the parental antigen binding polypeptide;

(2) the binding of the antigen binding polypeptide to an α/β T cell receptor (TCR)/CD3 complex is maintained or increased and the stability of the antigen binding polypeptide is increased compared to the parental antigen binding polypeptide; or

(3) the stability of the antigen binding polypeptide is increased compared to the parental antigen binding polypeptide.

10. A method for detecting, determining or enriching T cells expressing the α/β TCR/CD3 complex, comprising the step of contacting cells with the antigen binding polypeptide according to claim 1 .

11. A method of treating a patient who has cancer, comprising administering to the patient the composition of claim 7 .

12. The antigen binding polypeptide according to claim 2 , wherein the positively charged amino acid in the heavy chain at position 30 is R.

13. The antigen binding polypeptide according to claim 2 , wherein the positively charged amino acid in the heavy chain at position 30 is K.

14. The antigen binding polypeptide according to claim 2 , wherein the positively charged amino acid in the heavy chain at position 30 is H.

15. The antigen binding polypeptide according to claim 1 , wherein the VH comprises SEQ ID NO: 32 and the VL comprises SEQ ID NO: 2.