title: Cell-surface bound pertussis toxin induces polyclonal T cell responses with high levels of interferon-gamma in the absence of interleukin-12.
abstract: Pertussis toxin (PTx), an exotoxin produced by Bordetella pertussis, has long been used as a mucosal adjuvant. We examined the T cell stimulatory properties of PTx in order to dissect its mechanisms of adjuvanticity. PTx or the B-oligomer of PTx (PTxB) failed to activate purified murine CD4+ or CD8+ T cells, as measured by a lack of proliferation or expression of early T cell activation markers. However, these T cells proliferated extensively in response to the toxin in the presence of syngeneic DC, and proliferation was accompanied by a high level of IFN-gamma production in the absence of IL-12. Interestingly, such responses were independent of signals mediated by MHC-TCR interaction. Both PTx and PTxB were found to bind stably to the surface of DC, and increased the adherence of DC to surrounding cells. These data suggest that polyclonal T cell responses mediated by the toxin are likely to be caused by the toxin bound on the surface of APC, either cross-linking cell surface molecules on T cells, or directly stimulating T cells together with the co-stimulatory molecules expressed on APC. B. pertussis may use this toxin as a mechanism to evade a specific immune response.
authors.affiliation: The Edward Jenner Institute for Vaccine Research, Compton, England, UK. ayako.wakatsuki@path.ox.ac.uk
authors.forename: Ayako
authors.initials: A
authors.lastname: Wakatsuki
authors.forename: Persephone
authors.initials: P
authors.lastname: Borrow
authors.forename: Kevin
authors.initials: K
authors.lastname: Rigley
authors.forename: Peter C L
authors.initials: PC
authors.lastname: Beverley
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D003713:Dendritic Cells / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism*; D018664:Interleukin-12 / Q000378:metabolism*; D051379:Mice; D037342:Pertussis Toxin / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D018664:Interleukin-12; D007371:Interferon-gamma; D037342:Pertussis Toxin