Topological journey of parasite-derived antigens for presentation by MHC class I molecules

Trends Immunol. 2010 Sep 22. [Epub ahead of print]

Topological journey of parasite-derived antigens for presentation by MHC class I molecules

Blanchard N, Shastri N.

Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA; Current address: Physiopathology Research Centre of Toulouse-Purpan/INSERM U563, Department of Immunology and Infectious diseases, CHU Purpan, BP3028, 31024 Toulouse Cedex, France.

Abstract
Within cells of their host, many bacteria and parasites inhabit specialized compartments, such as a modified phagosome for Mycobacterium tuberculosis or a parasitophorous vacuole for Toxoplasma gondii. These locations could exclude microbial material from entry into the MHC class I surveillance pathway. Remarkably, however, under these circumstances, cells can still signal the presence of invading pathogens to circulating CD8(+) T cells, which typically play a key role in protection against such intracellular organisms. Here, we review MHC I presentation pathways in various contexts, ranging from model antigens in non-infectious settings to pathogen-infected cells. We suggest that presentation of intracellular pathogens can be described as not just one, but several distinct pathways; perhaps because diverse pathogens have evolved different strategies to interact with host cells.

PMID: 20869317 [PubMed - as supplied by publisher]