Authors:
Genc Basha, Kyla Omilusik, Ana Chavez-Steenbock, Anna T Reinicke, Nathan Lack, Kyung Bok Choi, & Wilfred A Jefferies
Summary:
Immune responses are initiated and primed by dendritic cells (DCs) that cross-present exogenous antigen. The chaperone CD74 (invariant chain) is thought to promote DC priming exclusively in the context of major histocompatibility complex (MHC) class II. However, we demonstrate here a CD74-dependent MHC class I cross-presentation pathway in DCs that had a major role in the generation of MHC class I–restricted, cytolytic T lymphocyte (CTL) responses to viral protein– and cell-associated antigens. CD74 associated with MHC class I in the endoplasmic reticulum of DCs and mediated the trafficking of MHC class I to endolysosomal compartments for loading with exogenous peptides. We conclude that CD74 has a previously undiscovered physiological function in endolysosomal DC cross-presentation for priming MHC class I–mediated CTL responses.
Source:
Nature Immunology; 13, 237-245 (02/05/12)