STIMULATION OF GASTROINTESTINAL ANTIBODY TO SHIGA TOXIN BY OROGASTRICIMMUNIZATION IN MICE

Shiga toxin (ST) is a protein toxin of Shigella dysenteriae type 1, a causative agent of severe diarrhoea and dysentery. In this report we d escribe the gastrointestinal secretory antibody response of mice follo wing orogastric immunization with ST. Gastrointestinal secretions were sampled by a gastrointestinal lavage technique weekly for 5 weeks aft er initial immunization. Assay of lavage samples by ELISA showed that mice vaccinated orogastrically with various doses of ST developed gast rointestinal antibody to ST in a dose-dependent manner. Serum anti-ST activity developed by 5 weeks after initial immunization. The ability of ST to act as a mucosal immune adjuvant was investigated by coadmini stration of ST and keyhole limpet haemocyanin. In contrast to cholera toxin, a potent adjuvant, ST did not demonstrate adjuvant activity. Th e mouse gastrointestinal lavage model could be useful for further anal ysis of the cellular basis of ST immunogenicity.