Contradictory responses in induction of delayed type hypersensitivity in orally immunized mice

Induction of delayed type hypersensitivity (DTH) in mice fed with sheep red blood cells (SRBC) and live Vibrio cholerae (V. cholerae) both forcedly and ad lib was comparatively investigated. Although suppression of DTH to SRBC or V. cholerae was induced in mice fed forcedly for 1 or 2 weeks, mice fed ad lib could produce the positive footpad reactions to antigens. Furthermore, the suppression of DTH in forcedly fed mice showed an antigenic specificity. These observations indicated that the induction of unresponsiveness to DTH in orally immunized mice was markedly influenced by the oral administration.