High throughput epitope identification and t cell receptor specificity determination using loadable detection molecules

The present invention relates to detection of interactions between antigenic peptides and binding partners, such as T cell receptors (TCR) and antigenic peptide responsive T cells. In particular, the present invention relates to the provision of loadable detection molecules with peptide-free MHC molecules utilized for high throughput epitope identification and TCR specificity determination. Each of the at least one antigenic peptide is represented by at least two different detectable labels, or at least one detectable label which is a nucleic acid label. The interaction between a T cell receptor (TCR) or antigenic peptide responsive T cell and a library of antigenic peptides can be determined. The T peptide-free MHC class I molecule comprise a heavy chain comprising an alpha-1 domain and an alpha-2 domain connected by a disulfide bridge, with a mutant cysteine residue positioned at amino acid residue 84 or 85 in the alpha-1 domain and a mutant cysteine residue positioned at amino acid residue 139 in the alpha-2 domain. A composition comprising at least two loadable detection molecules or at least three loadable detection molecules each comprising a different detectable label is also claimed.