Innate immune activation of CD4 T cells in Salmonella-infected mice is dependent on IL-18

Aparna Srinivasan, Rosa Maria Salazar-Gonzalez, Michael Jarcho, Michelle M. Sandau, Leo Lefrancois, Stephen J Mcsorley

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Production of IFN-γ by CD4 T cells is generally thought to be mediated by TCR triggering, however, Ag-nonspecific activation of effector CD8 T cells has been reported in infection models. In this study, we demonstrate that Ag-experienced CD4 T cells in the spleen of Salmonella-infected mice acquire the capacity to rapidly secrete IFN-γ in response to stimulation with bacterial lysate or LPS. This innate responsiveness of T cells was transient and most apparent during, and immediately following, active Salmonella infection. Furthermore, innate T cell production of IFN-γ in response to bacterial lysate or LPS was Ag independent and could be induced in Listeria-infected mice and in the absence of MHC class II expression. IL-18 was required for maximal innate responsiveness of CD4 T cells in Salmonella-infected mice and for optimal bacterial clearance in vivo. These data demonstrate that CD4 T cells acquire the capacity to respond to innate stimuli during active bacterial infection, a process that may contribute significantly to amplifying effector responses in vivo.

Original languageEnglish (US)
Pages (from-to)6342-6349
Number of pages8
JournalJournal of Immunology
Issue number10
StatePublished - May 15 2007
Externally publishedYes

ASJC Scopus subject areas

  • Immunology


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