Method for identifying a T-cell receptor protective against a disease

1. A method for identifying a T-cell receptor (TCR) protective against a disease, which comprises the following steps:

i) obtaining T cells from a donor non-human animal which comprises T cells protective against the disease amongst its complete T cell repertoire;

ii) adoptive transfer of the T cells into a plurality of T-cell deficient recipient non-human animals in a number such that, following subsequent disease challenge, at least one recipient animal is protected against the disease but at least one animal remains un-protected;

iii) analyzing TCRVβ sequences of TCR(s) present in the at least one protected and the at least one unprotected animals; and

iv) identifying a TCR protective against the disease by identifying TCRVβ sequence(s) present in the at least one protected animal and not present in the at least one unprotected animal.

2. A method according to claim 1 wherein the donor animal is an immunologically responding non-human animal.

3. A method according to claim 1 , wherein the number of cells appropriate for use in step ii is determined by performing a limiting dilution analysis.

4. A method according to claim 1 , wherein the number of T cells transferred to each recipient animal is such that less than half of the recipient animals are protected against the disease.

5. A method according to claim 4 , wherein the number of T cells transferred to each recipient animal is such that less than 10% of the recipient animals are protected against the disease.

6. A method according to claim 1 , wherein fewer than 1000 T cells are transferred to each recipient animal.

7. A method according to claim 1 , wherein the T cells collected from the donor animal are sorted to increase the proportion of CD4+ or CD8+ cells prior to adoptive transfer.

8. A method according to claim 1 , wherein T cells from a protected recipient animal are sorted into CD4+ or CD8+ cell subsets prior to analyzing the TCRVβ sequences.

9. A method according to claim 1 , wherein the donor and recipient non-human animals are transgenic for human MHC.

10. A method for screening for an antigen or antigenic determinant which is capable of inducing a protective immune response, which comprises the following steps:

(i) identifying a protective TCR by the method according to claim 1 ;

(ii) producing a cell expressing the protective TCR;

(iii) using the TCR-expressing cell to screen candidate antigens/antigenic determinants; and

(iv) selecting an antigen/antigenic determinant recognised by the protective/effective TCR.

11. A method according to claim 1 , which also comprises the step:

(v) identifying the TCRVα chain(s) which correspond(s) to the identified TCRVβ sequence(s).

12. A method for identifying a T-cell receptor (TCR) protective against a disease comprising the following steps:

i) obtaining T cells from a donor non-human animal which comprises T cells protective against the disease amongst its complete T cell repertoire;

ii) adoptive transfer of a restricted repertoire of the T cells into a plurality of T-cell deficient recipient non-human animals in a number such that, following subsequent disease challenge, at least one recipient animal is protected against the disease but at least one animal remains un-protected;

iii) analyzing TCRVβ sequences of TCR(s) present in the protected and unprotected animals; and

iv) identifying a TCR protective against the disease by identifying TCRVβ sequence(s) present in the at least one protected animal and not present in the at least one unprotected animal.

13. The method of claim 12 , wherein the restricted repertoire of T cells comprises 100 to 1000 T cells.