EVOLUTION OF A COMPLEX T-CELL RECEPTOR REPERTOIRE DURING PRIMARY AND RECALL BACTERIAL-INFECTION

The mechanisms underlying the genesis and maintenance of T cell memory remain unclear. In this study, we examined the evolution of a complex , antigen-specific T cell population during the transition from primar y effector to memory T cells after Listeria monocytogenes infection. T cell populations specific for listeriolysin O (LLO)(91-99), the immun odominant epitope recognized by H2-K-d-restricted T lymphocytes, were directly identified in immune spleens using tetrameric H2-K-d-epitope complexes. The T cell receptor (TCR) V beta repertoire of specific T c ells was determined by direct, ex vivo staining with a panel of mAbs. We demonstrate that LLO91-99-specific, primary effector T cell populat ions have a diverse TCR V beta repertoire. Analyses of memory T cell p opulations demonstrated similar TCR diversity. Furthermore, experiment s with individual mice demonstrated that primary effector and memory T cells have indistinguishable TCR repertoires. Remarkably, after reinf ection with L. monocytogenes, LLO91-99-specific T cells have a narrowe r TCR repertoire than do primary effector or memory T cells. Thus, our studies show that the TCR repertoire of primary effector T lymphocyte s is uniformly transmitted to memory T cells, whereas expansion of mem ory T cells is selective.