Failure of antigen-stimulated γδ T cells and CD4+ T cells from sensitized cattle to upregulate nitric oxide and mycobactericidal activity of autologous Mycobacterium avium subsp. paratuberculosis-infected macrophages

摘要: The function of γδ T cells during ruminant paratuberculosis (Johne's disease) is presently unknown. An ex vivo system was used to test the hypothesis that are capable activating Mycobacterium avium subsp. paratuberculosis-(M. paratuberculosis)-infected macrophages. Peripheral blood-derived macrophages were infected in vitro with live M. paratuberculosis, and autologous LN-derived or CD4+ co-cultured for 48 h, at which time bacterial survival as well production nitrites IFN-γ evaluated. Incubation paratuberculosis-infected did not result reduced intracellular viability compared macrophage cultures without added cells. by-infected containing enhanced alone. Although infection caused increased both post-infection day (PID) 0 PID 60, addition further increase nitrite production. In contrast, PPD-stimulated obtained 60 resulted significantly unstimulated antigen-stimulated However, by co-cultures killing additional experiments, macrophages, but uninfected unable when stimulated recombinant IFN-γ. Taken together, data suggest (1) do produce significant NO from vitro, (2) calves insufficient enhance mycobacterial (3) may have an impaired response following infection, even presence concentrations