Repetitive antigen stimulation induces stepwise transcriptome diversification but preserves a core signature of memory CD8+ T cell differentiation

Abstract

Repetitive antigen stimulation by prime-boost vaccination or pathogen reencounter increases memory CD8+ T cell numbers, but the impact on memory CD8+ T cell differentiation is unknown. Here we showed that repetitive antigen stimulations induced accumulation of memory CD8+ T cells with uniform effector memory characteristics. However, genome-wide microarray analyses revealed that each additional antigen challenge resulted in the differential regulation of several hundred new genes in the ensuing memory CD8+ T cell populations and, therefore, in stepwise diversification of CD8+ T cell transcriptomes. Thus, primary and repeatedly stimulated (secondary, tertiary, and quaternary) memory CD8+ T cells differed substantially in their molecular signature while sharing expression of a small group of genes and biological pathways, which may constitute a core signature of memory differentiation. These results reveal the complex regulation of memory CD8+ T cell differentiation and identify potential new molecular targets to dissect the function of memory cells generated by repeated antigen stimulation. © 2010 Elsevier Inc.