Suppression of adaptive immunity to heterologous antigens by SJ16 of Schistosoma japonicum.
ABSTRACT Despite the great effort that has been given to control the disease, schistosomiasis remains the most important human helminth infection in terms of morbidity and mortality. Natural infection of schistosomes induces very little protective immunity against reinfection. Moreover, effective schistosome vaccines for practical use have not been developed. These parasites appear to have evolved highly effective modulatory mechanisms on their host's immune system that promote the parasites' survival and also hinder the development of effective strategies for treatment of the disease. Understanding of the mechanisms of schistosome-mediated immune modulation would be most helpful in schistosomiasis prevention and control. Previously, we have identified from Schistosoma japonicum an anti-inflammatory protein, Sj16, which suppresses thioglycollate-induced peritoneal inflammation in BALB/c mice, as well as thioglycollate-mediated peritoneal macrophage maturation, while modulating cytokine and chemokine production from peritoneal cells. In the present study, we have further investigated the modulatory effect of Sj16 on the host's adaptive immunity to heterologous antigens with the use of recombinant Sj16 (rSj16) expressed and purified from Escherichia coli . Results from this study indicate that rSj16 significantly suppresses antibody production, in addition to Th1 and Th2 responses to heterologous antigens in the BALB/c mouse model. Our study also reveals that rSj16 suppresses lipopolysaccharide-induced major histocompatibility complex II expression and IL-12 production, while increasing IL-10 production in resident peritoneal macrophages. These results may partially explain why parasite-related antigens cannot mount a protective immunity during early stages of schistosome infection.
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ABSTRACT: Dendritic cells (DCs) and macrophages are antigen-presenting cells (APCs) that are important in innate immune defense as well as in the generation and regulation of adaptive immunity against a wide array of pathogens. The genitourinary (GU) tract, which serves an important reproductive function, is constantly exposed to numerous agents of sexually transmitted infections (STIs). To combat these STIs, several subsets of DCs and macrophages are strategically localized within the GU tract. In the female genital mucosa, recruitment and function of these APCs are uniquely governed by sex hormones. This review summarizes the latest advances in our understanding of DCs and macrophages in the GU tract with respect to their subsets, lineage, and function. In addition, we discuss the divergent roles of these cells in immune defense against STIs as well as in maternal tolerance to the fetus.Mucosal Immunology 12/2008; 1(6):451-9. · 7.00 Impact Factor
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ABSTRACT: Biological effects of in vivo transfection of a potential anti-inflammatory gene, designated Sm16, cloned from the human parasite Schistosoma mansoni were analyzed in these studies. A single intradermal injection of a full-length cDNA of Sm16 resulted in the expression of Sm16 in the epidermis, dermis, skin migratory cells and skin-draining lymph nodes of mice for up to 7 days. Subsequently the anti-inflammatory effect of this gene expression was evaluated by inducing an inflammatory response in the skin of mice. These studies showed that Sm16 gene delivery resulted in a significant suppression of cutaneous inflammation as shown by a reduction in cutaneous edema, decrease in neutrophil infiltration, suppression of pro-inflammatory cytokine expression and down-regulation of ICAM-1 expression in the skin inflammatory site. Cells collected from the skin-draining lymph nodes showed reduced proliferation to mitogen. Multiple intradermal injection of Sm16 cDNA failed to induce any antibody response in mice for up to 8 weeks after initial injection. These findings suggest a potential for developing Sm16 gene delivery as a therapeutic agent for treating inflammatory skin disorders.Gene Therapy 02/2002; 9(1):38-45. · 4.32 Impact Factor
- Advances in Immunology 02/2000; 75:159-208. · 7.26 Impact Factor