SYSTEMIC AND MUCOSAL ANTIBODY-RESPONSES TO GROUP-B STREPTOCOCCI FOLLOWING IMMUNIZATION OF THE COLONIC-RECTAL MUCOSA

The cervico-vaginal mucosa is poorly designed for inducing a mucosal i mmune response, but it can effect such a response evoked at other muco sal sites. This study was undertaken to determine whether colonic-rect al immunization with group B streptococci (GBS) might induce a local c ervico-vaginal immune response. Mice were immunized with either fragme nted GBS rectally, whole GBS rectally, or whole GBS subcutaneously. Ch olera toxin (CT) was used as an adjuvant for the rectal immunizations, Following colonic-rectal immunization with whole GBS, the mean anti-G BS IgA antibody level in vaginal secretions was 735 kU/ml, with indivi dual values reaching 3480 kU/ml. Corresponding levels of lgA antibodie s never exceeded 10 kU/ml in serum and intestinal secretions, or 90 kU /g in feces, In vaginal secretions IgA antibodies to GBS also constitu ted a much larger fraction of total IgA than in serum, intestinal secr etions and feces, Immunizations with fragmented GBS produced much lowe r IgA responses, Anti-GBS IgA response at the inductive site in the co lon-rectum was not significant, as opposed to a strong anti-CT IgA res ponse. Except in serum, the anti-GBS IgG responses to colonic-rectal i mmunizations were generally low, or absent. The results may provide a basis for the development of mucosal vaccines against GBS-infection.