Influence of the potency of antigen presentation on CD8+ T cell differentiation and memory

Abstract

CD8+ T cells curtail the proliferation of intracellular pathogens. However, the influence of the potency of stimulation on the development of CD8+ T cell memory is not clear. Using recombinant Ovalbumin (OVA) expressing intracellular bacteria, Mycobacterium bovis (BCG) which induces muted T cell activation, and Listeria monocytogenes (LM) which induces massive T cell activation, the influence of T cell stimulation on memory development was discerned. It was hypothesized that muted activation of CD8+ T cells by BCG might result in impaired development of memory. It was found that in contrast to LM naive as well as memory CD8+ T cells undergo delayed and muted expansion and contraction during BCG infection. Memory CD8+ T cells remained functional as they expressed cytokines, killed targets and proliferated in response to antigen. Furthermore, inflammatory cytokines and T cells curtail antigen-presentation during BCG infection which curbs T cell stimulation and favors the development of functional memory.