Abstract
The exact mechanisms of CD4 help in the generation of memory cytotoxic T lymphocytes (CTLs) remain largely illusive. We propose that dendritic cells (DCs) first interact with CD4(+) T cells, resulting in DC licensing and CD4(+) T-cell priming. Thereafter, CD8(+) T cells can receive stimulatory signals from DC-CD4(+) T-cell clusters and as well as individually from licensed DCs and primed CD4(+) T cells.