Cutting Edge: Characterization of Allorestricted and Peptide-Selective Alloreactive T Cells Using HLA-Tetramer Selection

Abstract

The vast majority of alloreactive T cells recognize foreign MHC molecules in a peptide-dependent manner. A subpopulation of these peptide-dependent alloreactive T cells is peptide-specific and contains T cells that are of interest for tumor immunotherapy. Allorestricted T cells (i.e., peptide-specific and alloreactive) specific for tumor-associated Ags can be raised in vitro. However, it is technically difficult to distinguish between peptide-specific and peptide-nonspecific alloreactive T cells by functional assays in vitro. Here we show for the first time that allorestricted T cells specifically bind HLA-peptide tetrameric complexes, as nominal Ag-specific T cells would do. In consequence, fluorescent HLA-peptide tetrameric complexes can be used for sorting and cloning of allorestricted CTLs specific for a peptide of interest. We also show by the mean of HLA-peptide tetramers the existence of peptide-selective alloreactive T cells that recognize a conformation on the foreign-MHC brought about by some but not all peptides bound.

Investigation of Peptide Involvement in T Cell Allorecognition Using Recombinant HLA Class I Multimers

“…Because the tetramer-negative cells are not peptide independent, we assume that they comprise T cells specific for other peptides from among the many known to be bound endogenously by HLA-A*0201 (27). Two reports describe examples of alloreactive T cells that are peptidedependent but not peptide-specific based on their ability to bind tetramers comprising several different peptide combinations presented by HLA-A*0201 (6,34). However, in both studies, the T cells were produced by stimulation with high densities of a single HLA class I/peptide combination that may artificially promote MHC structure-specific recognition.…”

Direct recognition by αβ cytolytic T cells of Hfe, a MHC class Ib molecule without antigen-presenting function

“…Several TCR͞peptide͞MHC crystal structures have shown that the ␣1-and ␣2-helices of the MHC molecules are contacted by the TCR ␣-and ␤-chain complementarity-determining regions (CDR)1͞CDR2, the bound peptides interacting essentially with the hypervariable CDR3s (4). The dual selectivity of some alloreactive CTL clones for a given allogeneic molecule and a given peptide presented by this molecule might suggest that effective TCR͞MHC molecule interaction always requires a direct participation of the bound ligand (5,6). However, less stringent peptide selectivity has been documented for other CTL clones (7,8), suggesting in those cases predominant TCR interaction with the ␣1␣2-helices of their allogeneic MHC molecular targets.…”

Transgenic antigen-specific, HLA-A*02:01-allo-restricted cytotoxic T cells recognize tumor-associated target antigen STEAP1 with high specificity

“…[11][12][13][14] Further, characterization, cloning and expression of tumor-specific T cell receptors (TCRs) derived from such T cells and their subsequent expression in T cells for adoptive transfer 15 is now an established procedure. Landmark clinical trials with a TCR specific for NY-ESO-1 already demonstrated the great potential of this approach.…”