Cognate CD4⁺ T cell licensing of dendritic cells in CD8⁺ T cell immunity

Nature immunology. 5, 1143-1148（2004）

Speaker：劉蓉燕                  Time：2004/12/15 15:00-16:00

Commentator：黎煥耀 老師         Place：Room 601

Abstract :

  Previous studies have suggested that dendritic cells（DCs） can be activated by cognate CD4⁺ T cells, which corecognize the same DC, via CD40 ligation to become potent stimulators to prime CTLs immunity. However, direct CD40 signaling of CTLs has been reported, and the role of DCs seems only to pull CD4⁺ T cell close to CD8⁺ T cell, but not to prime it. Because of these disparate findings, the authors wanted to know whether T_H cells are required to license DC_s for the priming of CTL_s immunity to herpes simplex virus 1（HSV-1）. In this study, they began to examine infection of HSV-1 lead to CTLs priming by CD4⁺ T cells. Further proving cognate manner, they generated a system of mixed chimeric mice in which DC_s only be recognized by either CD4⁺ or CD8⁺ T cells, and incapable of cognate interaction. They found purified CD8⁺ DCs, which were shown to prime immunity to HSV-1, from the chimera is not effective in vitro at priming CD8⁺ T cells, comparing with which from normal chimera . Furthermore, specific to ovabulmin（OVA）transgenic CD8⁺ T cells priming by OVA-loaded licensed DCs in vitro requires the active involvement of CD4⁺ T cells and cognate help. This data suggest licensed DC by cognate CD4⁺ T cell is indeed required for effective activating CD8⁺ T cells. Finally, the authors showed adopted CD8⁺ T cells primed by licensed DC_s to wild-type mice still have ability to develop to memory CD8⁺ T cells. In a word, the authors proved only after licensed by cognate CD4⁺ T cells DC_s prime the differentiation of CD8⁺ T cells into effective killers and memory cells.

Reference :

1.     Smith C.M. et al. Cognate CD4 T cell licensing of dendritic cells in CD8 T cell immunity. Nat. Immunol. 5, 1143-1148（2004）

2.     Philip G Ashton-Rickart. A license to remember. Nat. Immuinol. 5, 1097-1098（2004）

3.     Bevan, M.J. Helping the CD8 T-cell response. Nat. Rev. Immunol. 4,595-602（2004）