Gestation and breastfeeding in schistosomotic mothers differently modulate the immune response of adult offspring to postnatal Schistosoma mansoni infection

Schistosoma mansoni antigens in the early life alter homologous and heterologous immunity during postnatal infections. We evaluate the immunity to parasite antigens and ovalbumin (OA) in adult mice born/suckled by schistosomotic mothers. Newborns were divided into: born (BIM), suckled (SIM) or born/suckled (BSIM) in schistosomotic mothers, and animals from noninfected mothers (control). When adults, the mice were infected and compared the hepatic granuloma size and cellularity. Some animals were OA + adjuvant immunised. We evaluated hypersensitivity reactions (HR), antibodies levels (IgG1/IgG2a) anti-soluble egg antigen and anti-soluble worm antigen preparation, and anti-OA, cytokine production, and CD4+FoxP3+T-cells by splenocytes. Compared to control group, BIM mice showed a greater quantity of granulomas and collagen deposition, whereas SIM and BSIM presented smaller granulomas. BSIM group exhibited the lowest levels of anti-parasite antibodies. For anti-OA immunity, immediate HR was suppressed in all groups, with greater intensity in SIM mice accompanied of the remarkable level of basal CD4+FoxP3+T-cells. BIM and SIM groups produced less interleukin (IL)-4 and interferon (IFN)-g. In BSIM, there was higher production of IL-10 and IFN-g, but lower levels of IL-4 and CD4+FoxP3+T-cells. Thus, pregnancy in schistosomotic mothers intensified hepatic fibrosis, whereas breastfeeding diminished granulomas in descendants. Separately, pregnancy and breastfeeding could suppress heterologous immunity; however, when combined, the responses could be partially restored in infected descendants.

Immunological studies on mice vaccinated with irradiated cercaria and IL-12 against schistosoma mansoni infection

Protective immunity against Schistosoma mansoni infection correlates with increased levels of IgE and blood eosinophilia which are considered as markers of anti-parasitic cell-mediated immunity. IL-5 participates as well in the induction and regulation of IgE and eosinophilia, consequently in the development of acquired immunity. Swiss Webster female mice were subcutaneously injected with either 50 micro g of gamma-irradiated cercarial homogenate [400 Gy] twice weekly for three weeks alone or plus a single dose of IL-12 [0.8 ng/Kg]. The efficiency of immunization regimens were assessed 45 days post infection with 100 live cercariae/mouse by the number of worm burden, ova count, production of IL-5, eosinophils, and IgE levels in the vaccinated groups compared with the non-immunized group. The results demonstrated a significant reduction of ova count in the livers of vaccinated groups [57.19 and 40.13%] and worm couples compared with the non -immunized group. Furthermore, a decrease of IL-5 level as well as eosinopenia was recorded in both vaccinated groups. Scanning electron microscope [SEM] of adult worms recovered from the immunized groups revealed marked damage on the tegumental surface in males rather than females as well as constrictions and intensive corrugation of intertubercles