Distinct Roles for T Help and CD40/CD40 Ligand in Regulating Differentiation of Proliferation-Competent Memory CD8~+T Cells

摘要

Murine primary antiviral cytotoxic T cell(CTL)responses are often induced in the absence of Th cells.In this study,we show that virus-like particles,if combined with DNA rich in CpG motifs,efficiently trigger primary CTL responses and comparable frequencies of memory CTLs in the presence or absence of T help.However,memory CTLs primed in the absence of T help failed to proliferate upon viral challenge.Nevertheless,they were efficiently recruited to sites of inflammation,indicating that T help may regulate the balance between proliferation-competent and migration-competent memory CTLs.Surprisingly,generation of proliferation-competent memory CTLs was completely independent ofCD40 or CD40L,molecules commonly assumed to be central for mediating the beneficial effects of Th cells on CTL development.Thus,Th cells but not CD40/CD40L are key for the differentiation of proliferation-competent central memory CD8~+T cells.