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CD4 + T cells are required during priming but not the effector phase of antibody‐mediated IFN‐γ‐dependent protective immunity against pulmonary Francisella novicida infection
Author(s) -
Powell Heather J,
Cong Yu,
Yu JiehJuen,
Guentzel M Neal,
Berton Michael T,
Klose Karl E,
Murthy Ashlesh K,
Arulanandam Bernard P
Publication year - 2008
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.2008.31
Subject(s) - priming (agriculture) , immunity , effector , antibody , francisella , virology , biology , immunology , microbiology and biotechnology , immune system , francisella tularensis , virulence , genetics , gene , botany , germination
We have previously demonstrated the protective efficacy of intranasal vaccination with a defined Francisella tularensis subsp. novicida Δ iglC mutant (KKF24) against pulmonary F. novicida U112 challenge. In this study, we further characterized the mechanisms of KKF24‐induced immunity. Intranasally vaccinated KKF24 C57BL/6 major histocompatibility class (MHC) class II −/− mice produced minimal antigen‐specific interferon (IFN)‐γ and serum antibodies and were highly susceptible (0% survival) to F. novicida challenge, compared to MHC class I −/− or wild‐type mice (both 100% survival). Protective immunity could be transferred by immune serum into recipient wild type, but not IFN‐γ −/− mice. The protective effect of KKF24 vaccination against the respiratory F. novicida U112 challenge was not abrogated by anti‐CD4 neutralizing antibody treatment and was not conferred by adoptive transfer of KKF24‐specific CD4 + T cells. The protective effect of antibody was partially dependent upon Fc receptor‐mediated clearance. Taken together, our data indicate that CD4 + T cells are required for priming, but not during the effector phase, of anti‐KKF24 antibody‐mediated IFN‐γ‐dependent immunity against pulmonary F. novicida infection.