The role of IL-10 and IgG1 in the protection and granulomatous response inSchistosoma mansoni P24-immunized mice

Previous work by our laboratory identified a fraction of Schistosoma manson i soluble adult worm antigenic preparation, designated PIII, able to elicit significant in vitro cell proliferation, and lower in vitro and in vivo gr anuloma formation. In the present work, we investigated some biological act ivities of P24, an antigenic component of PIII. Immunization of mice with t his antigen induced a significant protection degree against challenge infec tion and significant decrease in the hepatic granuloma formation. Pre-incub ation of spleen cells from P24-immunized mice with S. mansoni antigens indu ced a significant increase of interleukin (IL)-10 levels, but not interfero n-gamma, in the cell supernatants. In addition, mice immunized with differe nt S. mansoni antigens and P24 displayed indistinguishable levels of IgG2a in response to anti-S. mansoni antigens, while IgG1 levels were significant ly increased. Collectively, our results indicate that P24 might mediate pro tective anti-parasite immunity and downregulate granulomatous hypersensitiv ity to S. mansoni eggs in part by its ability to induce a higher production of IgG1 and IL-10. (C) 2000 Elsevier Science Ltd. All rights reserved.