Individuality of Ag-selected and preimmune TCR repertoires

We have combined flow cytometry and single-cell PCR to characterize the TCR BV repertoires selected by individual mice in a model CD8 response against a defined peptide/MHC complex (CW3 170-179/Kd). Our results established tha t different mice select individually distinct yet structurally similar CW3- specific repertoires. Repertoire selection appears to be flexible depending on the immunizing cell dose. Using a single-donor, matched-pair-recipient adoptive transfer strategy, we demonstrated that the CW3-specific TCR reper toires of normal mice are already distinct at the preimmune level. We combi ne our data with computer simulations to test models for the composition of an Ag-specific preimmune repertoire and its selection during an immune res ponse.