INDIVIDUAL VARIATIONS IN THE MURINE T-CELL RESPONSE TO A SPECIFIC PEPTIDE REFLECT VARIABILITY IN NAIVE REPERTOIRES

Previous studies have analyzed the diversity of T cell responses upon immunization. Little is known, however, about the individual variabili ty of naive repertoires and its influence on immune responses. In the present study, T cells specific for a Kd-restricted epitope derived fr om HLA-AS were purified from individual immunized mice using tetramers of MHC-peptide. Their TCR beta chains were sequenced revealing strong biases but large variations in BJ usage and clonal composition. Most importantly, sequence analysis from nonimmunized mice demonstrated the preexistence of a small set of splenic precursors, distinct in each m ouse and comprising less than 200 cells. Therefore, differences in pre cursor pools appear to be the major source of individual variability i n antigen-selected repertoires.