Salivary, gut, vaginal and nasal antibody responses after oral immunization with biodegradable microparticles.

The aims of this study were to determine whether oral immunization with microparticles might lead to a common mucosal response including vaginal secretions. Female Balb/c mice were immunized orally with microparticles containing ovalbumin at 0 and 4 weeks or with soluble antigen. Antibody responses were assayed by ELISA in saliva, gut washings, vaginal washings and serum, and antibody producing cells were assayed by ELISPOT in salivary glands and nasal cavity. After primary immunization, IgA antibodies were detected in vaginal washings, saliva and in gut washings which were significantly greater than those detected with soluble antigen (P < 0.01). After secondary immunization, greatly enhanced antibody titres were found in three fluids. The specific activity (antibody per microgram IgA) of antibodies in vaginal fluid and saliva was significantly greater than in serum or gut wash (P < 0.01). Oral immunization also resulted in the development of antibody forming cells in salivary glands and in nasal associated mucosal tissue. Immunization with microparticles containing antigen should prove useful in immunization against infections affecting a number of different mucosal surfaces.