Antibody responses to bacterial antigens in the pregnant ewe.
The humoral immune response to the novel antigen Brucella abortus (S19) was examined in nonpregnant ewes and in ewes at different stages of pregnancy. Both the primary and secondary responses were monitored, by measuring the levels of total antibody, Immunoglobulin G (IgG), and complement fixing antibody. Results showed that total antibody production was significantly (p<0.01) impaired in late pregnancy and that IgG titres persisted at significantly (p<0.05) higher levels in non-pregnant animals late in the primary response and following the booster inoculation. Complement fixing antibody levels were significantly higher in non-pregnant ewes and animals inoculated post-partum. These results suggest that active immunity can be altered during pregnancy, with qualitative changes in the class and biological activity of antibody.
Reynolds
G E
GE
Department of Microbiology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Griffin
J F
JF