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The role of immunoproteasomes in antigen presentation and thymic selection (100.7). THE JOURNAL OF IMMUNOLOGY 2011. [DOI: 10.4049/jimmunol.186.supp.100.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Proteasomes, multisubunit complexes that degrade cellular proteins, are instrumental in forming epitopes for MHC class I antigen presentation. An alternate set of catalytic proteasome beta subunits are induced by IFN-gamma and expressed constitutively in dendritic cells, T-cells and B-cells. Immunoproteasomes containing these inducible subunits have increased chymotryptic and tryptic activities and decreased caspase-like activity, and are hypothesized to produce more peptides suitable for binding to MHC class I. To date mutant mice lacking one or two of the immunoproteasome subunits have been generated and have revealed some changes in MHC class I antigen presentation. However, the overall role of the immunoproteasome is unclear because mice that completely lack all three subunits have not been produced up until now. We have generated mice that completely lack immunoproteasomes. These animals have reduced presentation of MHC class I-presented peptides, and the peptides that are presented appear to be substantially different than those on cells from wild type mice. Moreover, the phenotype of these animals is distinct from mice lacking any individual immunoproteasome subunit. The loss of immunoproteasomes also affects T cell development in the thymus. The phenotype of these animals will be discussed.
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