title: Antigen processing and remodeling of the endosomal pathway: requirements for antigen cross-presentation.
abstract: Cross-presentation of endocytosed antigen as peptide/class I major histocompatibility complex complexes plays a central role in the elicitation of CD8(+) T cell clones that mediate anti-viral and anti-tumor immune responses. While it has been clear that there are specific subsets of professional antigen presenting cells capable of antigen cross-presentation, identification of mechanisms involved is still ongoing. Especially amongst dendritic cells (DC), there are specialized subsets that are highly proficient at antigen cross-presentation. We here present a focused survey on the cell biological processes in the endosomal pathway that support antigen cross-presentation. This review highlights DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, maturation-induced endosomal sorting of membrane proteins, dynamic remodeling of endosomal structures and cell surface-directed endosomal trafficking. We will conclude with the description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.
authors.affiliation: Department of Pediatric Immunology, University Medical Center Utrecht/Wilhelmina Children's Hospital Utrecht, Netherlands.
authors.forename: Ewoud Bernardus
authors.initials: EB
authors.lastname: Compeer
authors.forename: Thijs Willem Hendrik
authors.initials: TW
authors.lastname: Flinsenberg
authors.forename: Susanna Geertje
authors.initials: SG
authors.lastname: van der Grein
authors.forename: Marianne
authors.initials: M
authors.lastname: Boes