Ascaris suum: immunoelectrophoretic analysis of antigens in developmental stages

Extracts of Ascaris suum egg and adult worm share similar immunosuppressive properties

Adult Ascaris suum body extract (Asc) prepared from male and female worms (with stored eggs) down-regulates the specific immune response of DBA/2 mice to ovalbumin (OA) and preferentially stimulates a Th2 response to its own components, which is responsible for the suppression of the OA-specific Th1 response. Here, we investigated the participation of soluble extracts prepared from male or female worms or from eggs (E-Asc) in these immunological events. Extracts from either sex (1 mg/animal) or E-Asc (0.35 or 1 mg protein/animal) suppressed the delayed-type hypersensitivity (DTH) reaction (60-85%), proliferative response (50-70%), IL-2 and IFN-gamma secretion (below detection threshold) and IgG1 antibody production (70-90%) of DBA/2 mice to OA. A dose of 0.1 mg E-Asc/animal did not change DTH or proliferation, but was as effective as 0.35 mg in suppressing IL-2 and IFN-gamma, and OA-specific IgG1 antibodies. Lymph node cells from DBA/2 mice injected with Asc (1 mg/animal) or a high dose of E-Asc (1 mg protein/animal) secreted IL-4 upon in vitro stimulation with concanavalin A. As previously demonstrated for Asc, the cytokine profile obtained with the E-Asc was dose dependent and changed towards Th1 when a low dose (0.1 mg protein/animal) was used. Taken together, these results suggest that adult worms of either sex and eggs induce the same type of T cell response and share similar immunosuppressive properties.

Comparison of mouse strain skin sensitivities to anaphylactic mediators and susceptibility to passive cutaneous anaphylactic reactions

CFW, ICR, and C57Bl/6J mouse strains were examined and compared for their levels of skin sensitivity to histamine and mellitin (a potent mast cell degranulator) and for their susceptibilities to immunoglobulin E-induced passive cutaneous anaphylactic (PCA) reactions. ICR mice were found to exhibit the highest level of sensitivity to histamine and mellitin, whereas C57Bl/6J exhibited the least. CFW mice proved to be the best PCA recipients, whereas ICR mice were the poorest. On the basis of this evidence, no direct correlation is indicated between level of sensitivity to anaphylactic mediators and degree of susceptibility to immunoglobulin E-induced PCA reactions.