Induction of a protective immunity against Schistosoma mansoni with ovalbumin-coupled Sm37-5 coadsorbed with granulocyte-macrophage colony stimulating factor (GM-CSF) or IL-12 on alum

A previous study has shown that Sm37-5 is a major B cell epitope of Sm37-GAPDH. This epitope is highly antigenic in human infections and IgG antibody reactivity toward this determinant is associated with adolescent resistance to reinfection. This led us to test a synthetic peptide corresponding to Sm37-5, coupled to ovalbumin, as an anti-schistosome vaccine. Although mice injected with Sm37-5-OVA in Freund's adjuvant showed significant protection, immunization in aluminium hydroxide failed to induce protection. The adjuvant effect of cytokines (GM-CSF or IL-12) associated with the antigen on alum was investigated. With each of these two cytokines, significant reductions in the worm burden were obtained (32-38% with GM-CSF and 27% with IL-12, respectively). In addition, a reduction of the egg number trapped in the liver of immunized mice was also observed. Thus, protections were obtained with formulations that could potentially be used in humans. (C) 1998 Elsevier Science Ltd. All rights reserved.