Autoimmune component in individuals during immune response to inactivated combined vaccine against Q fever

Serum samples from 20 individuals immunized with inactivated combined vaccine (ICV) against Q fever and 10 individuals that received placebo were investigated on days 14, 21, 28 and 60 after immunization by isotope specific enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies directed to human IgA, IgM and IgG, and their fragments (F(ab')2, Fab, Fc). None of the subjects that received placebo exhibited significant increase of reactivity with any of the used antigens. By contrast, the sera of immunized individuals tended to show increased autoantibody activity with diverse antigens. Forty % of sera of immunized subjects exhibited anti-Fab activity, 20% of the sera recognized IgA, F(ab')2- and Fc-fragments, and 15% of the sera recognized IgG and IgM. Although there was wide variation in antibody levels and in isotypic heterogeneity of autoantibodies induced by immunization, anti-Fab autoantibodies were represented mainly by IgG and IgA isotypes but not IgM isotype. A direct correlation between the anti-Coxiella burnetii (anti-C.b.) antibody level and the anti-Fab IgG activity, and between the anti-C.b. antibody level and the anti-Fab IgA activity was found. In the group of vaccinees reacting strongly to the vaccine against Q fever, this correlation significantly increased for both the anti-Fab IgG and the anti-Fab IgA activities. No correlation was found with the sera in the group of the subjects that received placebo.