TCR libraries

1. A method of obtaining a T cell receptor that specifically binds a peptide antigen, comprising screening a library of particles displaying a plurality of different T cell receptors (TCRs) with the peptide antigen, wherein the plurality of TCRS consists essentially of TCRs comprising (a) an alpha chain variable domain (Vα) that is a TRAV12-2 gene product from a natural repertoire of TCRs, and (b) a beta chain, the beta chain comprising a beta chain variable domain (Vβ) that is a gene product of a TRBV gene, wherein the Vα CDR3 length varies among the plurality of displayed TCRs and the Vβ CDR3 length varies among the plurality of displayed TCR, wherein the TCRs are covalently linked to the particles, and wherein the particles are phage particles, ribosomes, yeast cells, or mammalian cells, the method comprising:

(1) panning the library using as a target the peptide antigen;

(2) repeating step (1) one or more times;

(3) screening the phage clones identified in step (1) or (2); and

(4) identifying a TCR that specifically binds the peptide antigen.

2. The method of claim 1 , wherein the single TRBV gene is one of:

TRBV1

TRBV2

TRBV3-1

TRBV3-2

TRBV4-1

TRBV4-2

TRBV4-3

TRBV5-1

TRBV5-2

TRBV5-3

TRBV5-4

TRBV5-5

TRBV5-6

TRBV5-7

TRBV5-8

TRBV6-1

TRBV6-2

TRBV6-3

TRBV6-4

TRBV6-5

TRBV6-6

TRBV6-7

TRBV6-8

TRBV6-9

TRBV7-1

TRBV7-2

TRBV7-3

TRBV7-4

TRBV7-5

TRBV7-6

TRBV7-7

TRBV7-8

TRBV7-9

TRBV8-1

TRBV8-2

TRBV9

TRBV10-1

TRBV10-2

TRBV10-3

TRBV11-1

TRBV11-2

TRBV11-3

TRBV12-1

TRBV12-2

TRBV12-3

TRBV12-4

TRBV12-5

TRBV13

TRBV14

TRBV15

TRBV16

TRBV17

TRBV18

TRBV19

TRBV20-1

TRBV21-1

TRBV22-1

TRBV23-1

TRBV24-1

TRBV25-1

TRBV26

TRBV27

TRBV28

TRBV29-1

TRBV30

3. The method of claim 1 , wherein the alpha chain variable domain and the beta chain variable domain are displayed as a single chain polypeptide.

4. The method of claim 1 , wherein the peptide antigen comprises HLA-A2.