Epitopes described in "Antigen-specific CD8(+) T cells fail to respond to Shigella flexneri."

Article Authors:Stephanie P Jehl; Amy M Doling; Kara S Giddings; Armelle Phalipon; Philippe J Sansonetti; Marcia B Goldberg; Michael N Starnbach
Article Title:Antigen-specific CD8(+) T cells fail to respond to Shigella flexneri.
Reference Detail
Reference ID:1022032
Abstract:CD8(+) T lymphocytes often play a primary role in adaptive immunity to cytosolic microbial pathogens. Surprisingly, CD8(+) T cells are not required for protective immunity to the enteric pathogen Shigella flexneri, despite the ability of Shigella to actively secrete proteins into the host cytoplasm, a location from which antigenic peptides are processed for presentation to CD8(+) T cells. To determine why CD8(+) T cells fail to play a role in adaptive immunity to S. flexneri, we investigated whether antigen-specific CD8(+) T cells are primed during infection but are unable to confer protection or, alternatively, whether T cells fail to be primed. To test whether Shigella is capable of stimulating an antigen-specific CD8(+) T-cell response, we created an S. flexneri strain that constitutively secretes a viral CD8(+) T-cell epitope via the Shigella type III secretion system and characterized the CD8(+) T-cell response to this strain both in mice and in cultured cells. Surprisingly, no T cells specific for the viral epitope were stimulated in mice infected with this strain, and cells infected with the recombinant strain were not targeted by epitope-specific T cells. Additionally, we found that the usually robust T-cell response to antigens artificially introduced into the cytoplasm of cultured cells was significantly reduced when the antigen-presenting cell was infected with Shigella. Collectively, these results suggest that antigen-specific CD8(+) T cells are not primed during S. flexneri infection and, as a result, afford little protection to the host during primary or subsequent infection.
Affiliations:Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Ave., Boston, MA 02115, USA.
Reference Type:Literature
PubMed ID:21357720
Journal:Infect Immun
Journal Volume:79
Article Pages:2021-30
Journal ISSN:0019-9567
Article Chemical List:Antigens, Bacterial;Epitopes, T-Lymphocyte
Article MeSH List:Animals; Antigens, Bacterial(immunology); CD8-Positive T-Lymphocytes(immunology); Dysentery, Bacillary(immunology); Epitopes, T-Lymphocyte(immunology); Immunoblotting; Lymphocyte Activation(immunology); Mice; Mice, Inbred C57BL; Shigella flexneri(immunology)
Curation Last Updated:2015-07-30 20:39:29