Cross-presentation of antigens by dendritic cells

Abstract

T lymphocytes recognize antigen presented on the surface of antigen-presenting cells by MHC class I and class II molecules. Classically, MHC class I molecules present self- or pathogen-derived antigens that are synthesized within the cell, whereas exogenous antigens derived via endocytic uptake are loaded onto MHC class II molecules for presentation to CD4+ T cells. It is becoming increasingly clear that some dendritic cells are also specialized to process exogenous antigens into the MHC class I pathway for presentation to CD8+ T cells. This process is known as cross-presentation. It provides a mechanism that can drive dendritic cells to generate either tolerance to self-antigens or immunity..