Cross-priming of CD8⁺ T cells stimulated by virus-induced TypeΙInterferon

Speaker: 顏廷穎                                  Commentator: 謝奇璋 醫師

Date: Nov. 19, 2003; 15:00~16:00

Abstract:

Previous studies showed that CD8⁺ T cells recognize antigens presented on MHC class I molecules, and this antigen presentation pathway is known as the endogenous pathway.  In contrast, MHC class II restricted pathway, which presents exogenous antigens to CD4⁺ T cells.  However, recent studies have demonstrated that exogenous antigens also can prime  CD8⁺ T cells in vitro, and this phenomenon is named cross-presentation.  Cross presentation has been reported in many tolergenic immune responses in vivo.  This may due to antigen presented cells cannot receive appropriate activation signals like viral components present in infected cells or host molecules in response to viral infection.

In this paper, the authors observed some viral infection, such as lymphocytic choriomentingitis virus infection, could active the CD8⁺ T cell response to exogenous antigen ovalbulmin.  They also found that IFN-a/b  was secreted during viral infection.   Published data indicated that IFN-a/b can enhance CD8⁺ T cell response both in vitro and in vivo.  Using mice deficient IFN-a/b, CD40 or MHC class II molecule, they found that CD8⁺ T cells could strongly cross-present exogenous antigens in vivo when mice were infected by virus.  Cross presentation were dependent on IFN-a/bfunctions but not CD4⁺ T helper cell or CD40 and CD40 ligand interaction.

References:

1. Kurts, C., Cannarile, M., Klebba, I. & Brocker, T.(2001) Dendritic cells are sufficient to cross-present self-antigens to CD8 T cells in vivo. J. Immunol. 166:1439-1442. 

2.Agnes Le Bon, Nathalie Etchart, Cornelia Rossmann, Miranda Ashton, Sam Hou, Dirk Gewert, Persephone Borrow, David F Tough (2003) Cross-priming of CD8⁺ T cells stimulated by virus-induced TypeΙ Interferon. Nature Immunol. 4:1009-1015.