LACTO-N-FUCOPENTAOSE-III (LEWIS(X)), A TARGET OF THE ANTIBODY-RESPONSE IN MICE VACCINATED WITH IRRADIATED CERCARIAE OF SCHISTOSOMA-MANSONI

Carbohydrates on soluble egg antigens are major epitopes for the antib ody responses of patients and mice infected,vith Schistosoma mansoni. Recently, protective sera of mice vaccinated with irradiated cercariae were shown to recognize carbohydrate epitopes on schistosomal glutath ione S-transferase. The present study demonstrates that carbohydrate e pitopes are major targets of sera from C57BL/6J and CBA/J mice vaccina ted with 15- or 50-kilorad-irradiated cercariae of S. mansoni. Antibod y titers to carbohydrate epitopes increased with the number of vaccina tions and were considerably higher in C57BL/6J mice than in CBA/J mice , The specificity of this anticarbohydrate response was determined by measuring antibody binding to defined oligosaccharide residues known t o be present on the parasite. A predominant target of the humoral anti carbohydrate response of vaccinated mice was lacto-N-fucopentaose III, a molecule relevant for cell trafficking. We observed no binding to i ts nonfucosylated homolog, lacto-N-neotetraose, or to oligosaccharides present on keyhole limpet hemocyanin. The strongest antibody response to lacto-N-fucopentaose III was observed for C57BL/6J and CBA/J mice repeatedly vaccinated with 15-kilorad-irradiated cercariae, which also achieve the highest levels of protection. Immunoglobulin M was the pr edominant antibody class binding to lacto-N-fucopentaose III. We concl ude that in the irradiated-cercaria vaccine model, C57BL/6J and CBA/J mice produce anticarbohydrate antibodies against various stages of S. mansoni and that the oligosaccharide lacto-N-fucopentaose III is one t arget of this response. Lacto-N-fucopentaose III and its specific anti bodies may profoundly affect host resistance and parasite homing.