CD40L-expressing CD8 T cells prime CD8α⁺ DC for IL-12p70 production

• Published in: European journal of immunology Vol. 38; no. 8; pp. 2251 - 2262
• Main Authors: Wong, Kok Loon, Lew, Fei Chuin, MacAry, Paul A, Kemeny, David M
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01.08.2008; WILEY‐VCH Verlag
• Subjects: CD8 T cells; Dendritic cells; IL‐12p70
• ISSN: 0014-2980; 1521-4141
• DOI: 10.1002/eji.200838199

CD8α⁺ DC are implicated as the principle DC subset for cross-presentation and cross-priming of cytotoxic CD8 T cell responses. In this study, we demonstrate another unique facet of the CD8α⁺ DC and CD8 T cell relationship, by showing that CD8 T cells reciprocally activate CD8α⁺ DC, but not CD8α⁻ DC, for IL-12p70 production, the key Th1-promoting cytokine. This effect was observed during an antigen-specific interaction between DC and activated CD8 T cells, along with secondary TLR stimulation of DC by LPS. Activated CD8 T cells use a combination of IFN-γ and CD40L, which is rapidly up-regulated post-stimulation, to prime DC for IL-12p70 production during an antigen-specific response. Our results suggest that the interaction between CD8α⁺ DC and antigen-primed CD8 T cells may form an important component of Th1-mediated immunity through the induction of IL-12p70.