Anti-miracidial effect of recombinant glutathione S-transferase 26 and soluble egg antigen on immune responses in murine schistosomiasis mansoni

The anti-miracidial potential of recombinant Schistosoma mansoni glutathion e S-transferase 26 (rSmCST26) or native crude soluble egg antigens (SEA) wa s assessed. The associated dynamics of granuloma formation and immune respo nses were evaluated. Naive C57BL/6 mice were injected intravenously with mu ltiple doses of either SEA (SEA-group) or rSmGST26 (GST-group) 7 days befor e cercarial infection. The immunized groups and the respective controls wer e sacrificed 6, 8 and 16 weeks postinfection (p.i.). Acceleration of ova de struction and reduction of granuloma diameter were greater in the GST-group than the SEA-group, mainly at 8 weeks p.i. However, the amelioration of he patic pathology and function was more evident in the SEA-group. Concurrentl y, serum-specific IgG1 levels were elevated throughout the course of infect ion in the immunized groups compared to the infected controls. Initial rise of all splenic cytokines and serum anti-SEA IgE levels at 6 weeks p.i. was observed, followed by a dramatic drop in the levels of the proinflammatory cytokines IL-2, IFN gamma, IL-4 and TNF-alpha and IgE at 8 weeks of infect ion. IL-10 level was lower at 8 weeks p.i. than at 6 weeks, but was higher in immunized groups than in infected controls. Several responses may be imp licated as an outcome of the present immunization protocol, such as increas ed levels of blocking antibody (IgG1) and IL-10 with decreased levels of pr oinflammatory cytokines and IgE.