Analysis of antibody response and immunoglobulins in sera of rabbits and guinea pigs immunized with Coxiella burnetii.

Rabbit and guinea pig sera and their immunoglobulin fractions (IgM and IgG) were examined by complement-fixation (CF), microagglutination (MA), opsonization-phagocytosis (OP) and serum protection (SP) tests at intervals after immunization with live phase I and phase II Coxiella burnetii suspensions. In general, MA antibodies, but also decreased, earlier than CF antibodies. The anamnestic immune response was higher with lower primary doses. Both phase II and phase I CF and MA antibodies as well as phase I opsonins and protective antibodies were found in either immunoglobulin fraction depending on post-immunization intervals. At later intervals and especially after the second immunizing dose the levels of protective antibodies in whole sera, but mainly in the IgG fractions, showed a better agreement with those of phase I opsonins rather than of phase I CF and MA antibodies.