The immune response of mice to bacterial antigens given by mouth.

The secretory and systemic antibody responses to oral dead Escherichia coli were examined in A strain mice. The best responses were obtained in mice dosed with 1 x 10(10) bacteria. Orally immunized animals showed an enhanced response to subsequent parenteral immunization with somatic antigens. This effect could be passively transferred with serum. In contrast, the response to the capsular antigen K88 was reduced in the same animals.