Coxiella burnetii Antigen-Stimulated Dendritic Cells Mediated Protection against Coxiella burnetii in BALB/c Mice

Abstract

Coxiella burnetii is the etiological agent of human Q fever. In this study, adaptive transfer of mouse bone marrow–derived dendritic cells (BMDCs) stimulated with C. burnetii antigen, phase I whole-cell antigen (PIAg), lipopolysaccharide (LPS)–removed PIAg (PIIAg), protein antigen Com1, or SecB significantly reduced coxiella burden in recipient mice compared with control mice. Mice that received PIIAg-pulsed BMDCs displayed substantially lower coxiella burden than recipient mice of PIAg-pulsed BMDCs after C burnetii challenge. The protection offered by the antigen-activated BMDCs was correlated with the increased proliferation of helper T (T_H) T_H1 CD4⁺ cells, preferential development of T_H17 cells, and impaired expansion of regulatory T lymphocytes. Our results suggest that PIIAg is far superior to PIAg in activating BMDCs to confer protection against C. burnetii in vivo, whereas Com1 and SecB are protective antigens because Com1- or SecB-pulsed BMDCs confer partial protection.