METHODS

1 - 12 . (canceled)

13 . A conjugated antibody which comprises a chemotherapeutic entity and which selectively binds either TCR beta constant region 1 (TRBC1) or TRBC2.

14 . The conjugated antibody according to claim 13 , wherein the chemotherapeutic entity is a cytotoxic drug.

15 . The conjugated antibody according to claim 13 , which selectively binds TRBC1.

16 . The conjugated antibody according to claim 15 , which has a variable heavy chain (VH) and a variable light chain (VL) which comprise the following complementarity determining regions (CDRs):

VH CDR1: SEQ ID NO: 7,

VH CDR2: SEQ ID NO: 8,

VH CDR3: SEQ ID NO: 9,

VL CDR1: SEQ ID NO: 10,

VL CDR2: SEQ ID NO: 11, and

VL CDR3: SEQ ID NO: 12.

17 . The conjugated antibody according to claim 16 , which comprises a variable heavy chain (VH) having the sequence shown as SEQ ID NO: 1 and a variable light chain (VL) having the sequence shown as SEQ ID NO: 2.

18 . The conjugated antibody according to claim 16 , which comprises a scFv having the sequence shown as SEQ ID NO: 3.

19 . The conjugated antibody according to claim 13 , which selectively binds TRBC2.

20 . A method for treating a T-cell lymphoma or leukaemia in a subject which comprises the step of administering a conjugated antibody according to claim 13 to the subject, to cause selective depletion of the malignant T-cells, together with normal T-cells expressing the same TRBC as the malignant T-cells, but not to cause depletion of normal T-cells expressing the TRBC not expressed by the malignant T-cells.

21 . The method according to claim 20 , wherein the method also comprises the step of investigating the TCR beta constant region (TCRB) of a malignant T cell from the subject to determine whether it expresses TRBC1 or TRBC2.

22 . A method for targeting the delivery of a chemotherapeutic entity to a cell which expresses either TRBC1 or TRBC2 in a subject comprising administering conjugated antibody according to claim 13 .

23 . A pharmaceutical composition which comprises a conjugated antibody according to claim 13 and a pharmaceutically acceptable carrier, diluent, excipient or adjuvant.

24 . A method for selecting a suitable therapy to treat a subject suffering from T-cell lymphoma or leukaemia which comprises:

a) determining whether a malignant T cell in a sample isolated from the subject expresses TRBC1 or TRBC2, and

b) selecting a conjugated antibody for use according to claim 13 based on the TRBC1 or TRBC2 expression of said malignant T cell.

25 . A method for selecting a subject suffering from T-cell lymphoma or leukaemia to receive a therapy comprising a conjugated antibody for use according to claim 21 , which comprises:

a) determining whether a malignant T cell in a sample isolated from the subject expresses TRBC1 or TRBC2, and

b) selecting said subject to receive a therapy based on a conjugated antibody for use according to claim 21 based on the TRBC1 or TRBC2 expression of said malignant T cell.

26 . A bispecific T-cell engager which comprises:

a) a first domain which selectively binds either TCR beta constant region 1 (TRBC1) or TRBC2, and

b) a second domain capable of activating a T cell.

27 . The bispecific T-cell engager according to claim 26 , wherein the first and the second domains are single-chain variable fragments (scFvs).

28 . The bispecific T-cell engager according to claim 26 , wherein the first domain selectively binds TRBC1.

29 . The bispecific T-cell engager according to claim 28 , wherein the first domain has a variable heavy chain (VH) and a variable light chain (VL) which comprise the following complementarity determining regions (CDRs):

VH CDR1: SEQ ID NO: 7,

VH CDR2: SEQ ID NO: 8,

VH CDR3: SEQ ID NO: 9,

VL CDR1: SEQ ID NO: 10,

VL CDR2: SEQ ID NO: 11, and

VL CDR3: SEQ ID NO: 12.

30 . The bispecific T-cell engager according to claim 29 , wherein the first domain comprises a variable heavy chain (VH) having the sequence shown as SEQ ID NO: 1 and a variable light chain (VL) having the sequence shown as SEQ ID NO: 2.

31 . The bispecific T-cell engager according to claim 29 , wherein the first domain comprises a scFv having the sequence shown as SEQ ID NO: 3.

32 . The bispecific T-cell engager according to claim 26 , wherein the first domain selectively binds TRBC2.

33 . A nucleic acid which encodes the bispecific T-cell engager according to claim 26 .

34 . A vector which comprises a nucleic acid according to claim 33 .

35 . A method for treating a T-cell lymphoma or leukaemia in a subject which comprises the step of administering a bispecific T-cell engager according to claim 26 to the subject, to cause selective depletion of the malignant T-cells, together with normal T-cells expressing the same TRBC as the malignant T-cells, but not to cause depletion of normal T-cells expressing the TRBC not expressed by the malignant T-cells.

36 . The method according to claim 35 , wherein the method also comprises the step of investigating the TCR beta constant region (TCRB) of a malignant T cell from the subject to determine whether it expresses TRBC1 or TRBC2.

37 . A pharmaceutical composition which comprises a bispecific T-cell engager according to claim 26 and a pharmaceutically acceptable carrier, diluent, excipient or adjuvant.

38 . A method for selecting a suitable therapy to treat a subject suffering from T-cell lymphoma or leukaemia which comprises:

a) determining whether a malignant T cell in a sample isolated from the subject expresses TRBC1 or TRBC2, and

b) selecting a bispecific T-cell engager for use according to claim 36 based on the TRBC1 or TRBC2 expression of said malignant T cell.

39 . A method for selecting a subject suffering from T-cell lymphoma or leukaemia to receive a therapy based on a bispecific T-cell engager for use according to claim 36 , which comprises:

a) determining whether a malignant T cell in a sample isolated from the subject expresses TRBC1 or TRBC2, and

b) selecting said subject to receive a therapy based on a bispecific T-cell engager for use according to claim 36 based on the TRBC1 or TRBC2 expression of said malignant T cell.