Major Histocompatibility Complex Class II-Restricted, CD4⁺T Cell-Dependent and -Independent Mechanisms Are Required for Vaccine-Induced Protective Immunity against<i>Coxiella burnetii</i>

Abstract

To understand the role of major histocompatibility complex class I (MHC-I) and MHC-II in vaccine-mediated protection against Coxiella burnetii , we evaluated the protective efficacy of a formalin-inactivated C. burnetii Nine Mile phase I vaccine (PIV) in β 2 -microglobulin-deficient (B2m KO) and MHC-II-deficient (MHC-II KO) mice. Vaccination reduced disease severity in wild-type (WT) and B2m KO mice but failed to reduce bacterial burden in MHC-II KO mice.