A comparison of specific antibody responses in mouse vaginal fluid after immunization by several routes.

Mice were immunized with a protein antigen, horse ferritin, by eight different routes and the immune responses in the reproductive tract were compared by measuring specific IgA and IgG in vaginal fluid and by localizing anti-ferritin plasma cells in uterine horns, cervix and vagina. The eight routes of immunization were: subcutaneous with Freund's adjuvant (s.c.), intragastric (i.g.), intravaginal (i.v.), s.c.-i.g., s.c.-i.v., i.g.-i.v., i.v.-i.v. and s.c.-i.g.-i.v. The largest overall response, considering both IgA and IgG antibodies, was obtained by s.c. priming with ferritin in adjuvant followed by i.v. boosting. Intravaginal immunization also boosted priming by the i.g., s.c.-i.g. and i.v. routes, but the response to i.v. immunization alone was weak. All i.v. immunizations stimulated mainly IgA antibody responses in vaginal fluid. Specific plasma cells, mostly of the IgG isotype, were present in the vaginal fornix of several mice in the s.c.-i.v. and s.c.-i.g.-i.v. groups, but none were detected there in any other group and they were only rarely observed in the uterine horns. The results provide data on the relative effectiveness of different routes of immunization in producing a humoral immune response in vaginal fluid against a non-replicating antigen.