Generation of female genital tract antibody responses by local or central (common) mucosal immunization

Genital antibody responses were compared in female mice immunized intravagi nally (i.vag.) or intranasally (i.n.) with a bacterial protein antigen (AgI /II of Streptococcus mutans) coupled to the B subunit of cholera toxin. Ser um and salivary antibodies were also evaluated as measures of disseminated mucosal and systemic responses. Although i;vag. immunization induced local vaginal immunoglobulin A (IgA) and IgG antibody responses, these were not d isseminated to a remote secretion, the saliva, and only modest levels of se rum antibodies were generated. In contrast, i.n. immunization was substanti ally more effective at inducing IgA and IgG antibody responses in the genit al tract and in the circulation, as well as at inducing IgA antibodies in t he saliva. Moreover, mucosal and systemic antibodies induced by i.n. immuni zation persisted for at least 12 months. Analysis of the molecular form of genital IgA indicated that the majority of both total IgA and specific IgA antibody was polymeric, and likely derived from the common mucosal immune s ystem.