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Updated: Jun 12, 2026

Visualizing Antigen Specific CD4+ T Cells using MHC Class II Tetramers
Published on: March 6, 2009
Direct CD4 help provision following interaction of memory CD4 and CD8 T cells with distinct antigen-presenting
Marie-Ghislaine de Goër de Herve1, Bamory Dembele, Mélissa Vallée
1Institut National de la Santé et de la Recherche Médicale U-1012, Université Paris-Sud, Faculté de Médecine, 94276 Le Kremlin-Bicêtre, France.
Abstract:
Accumulating evidence suggests that CD4 help is needed at the memory stage to mount effective secondary CD8 T cell responses. In this paper, we report that memory CD4 T cells can provide efficient help to memory CD8 T cells after interaction of the two lymphocytes with distinct dendritic cells. Provision of help to CD8 T cells required direct cell-cell contact and involved both IL-2 and CD40 ligation, within a CD4-CD8 T cell synapse. Thus, following antigenic interaction with APCs, activated memory CD4 and CD8 T cells appear to separate from their respective APCs before meeting each other for help provision, regardless of their Ag specificity. CD4 help for memory CD8 T cells therefore appears to be conditioned primarily not by Ag specificity but by activation status.
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