Implications of memory CD8 T cell quality for protective immunity

Abstract

The phenotype and functionality that CD8+ T cells acquire

upon encountering their cognate antigen depend on many factors that are

controlled by the nature of the pathogen The acquired phenotypical and

functional characteristics determine the potential of the CD8+ T cells to form bona fide memory populations that are able to expand upon secondary challenge. We investigated factors that control CD8+ T cell differentiation. We have shown that the height of the viral dose greatly impacts the immunological outcome by affecting the magnitude of the response and the phenotype and function of the (memory) CD8+ T cells that are induced. The acquired phenotype and functions determine the capacity to expand upon re-encounter with the same pathogen and we have shown that the IL-2 producing capacity of CD8+ T cells functions as a crucial determinant of CD8+ T cell expansion potential. Although we addressed only a small fraction of all variables involved in the induction and maintenance of antigen-specific T cell populations our observations and insights gathered by others already provide a basis for rational immunotherapeutic treatment design, however, for fine-tuning of therapy-induced immune responses aspects about e.g. the timing and cooperating signals still need to be understood in more detail.