Characterization of the mucosal and systemic immune response induced by Cry1Ac protein from Bacillus thuringiensis HD 73 in mice

The present paper describes important features of the immune response induc ed by the Cry1Ac protein from Bacillus thuringiensis in mice. The kinetics of induction of serum and mucosal antibodies showed an immediate production of anti-Cry1Ac IgM and IgG antibodies in serum after the first immunizatio n with the protoxin by either the intraperitoneal or intragastric route. Th e antibody fraction in serum and intestinal fluids consisted mainly of IgG1 . In addition, plasma cells producing anti-Cry1Ac IgG antibodies in Peyer's patches were observed using the solid-phase enzyme-linked immunospot (ELIS POT). Cry1Ac toxin administration induced a strong immune response in serum but in the small intestinal fluids only anti-Cry1Ac IgA antibodies were de tected. The data obtained in the present study confirm that the Cry1Ac prot oxin is a potent immunogen able to induce a specific immune response in the mucosal tissue, which has not been observed in response to most other prot eins.