Abstract
It was shown in our previous paper that mice primed with chemically modified bacterial α-amylase (BαA), which was neither cross-reactive with antiBαA antibody nor able to induce a humoral anti-BαA response, developed enhanced responses to a subsequent challenge with native BαA and that the magnitude of the immunological memory was closely related to the priming dose of modified BαA. This paper describes the experimental conditions for induction of delayed hypersensitivity (DH) by modified BαA in relation to the development of immunological memory for antibody response to native BαA.
Mice primed with either an intraperitoneal (i.p.) or subcutaneous (s.c.) injection of modified BαA in complete Freund's adjuvant (CFA) developed enhanced anti-BαA responses to a subsequent challenge with BαA. In contrast, when mice were immunized with an s.c. injection of the modified BαA only, a significant level of DH to native BαA could be induced, as measured by the footpad reaction (FPR). The highest degree of DH was observed in mice given 50 μg of modified BαA. DH was detectable within 5 days and persisted for 25 days after immunization. In the reciprocal combination of native BαA as the immunogen and modified BaA as the eliciting antigen, the relationship of anti-BαA responses to DH was examined. The primary anti-BαA responses induced by an i.p. injection of large doses of BaA was markedly higher than those induced by an s.c. injection, while DH was exhibited only in mice given an s.c. injection of BαA in CFA.
With respect to DH to native BαA induced by the modified BαA, it was shown that C3H/He mice were high and C57BL/6 mice were low responders.
