SHORT REPORT - IDENTIFICATION OF B-CELL EPITOPES IN THE SERINE-RICH ENTAMOEBA-HISTOLYTICA PROTEIN

The serine-rich Entamoeba histolytica protein (SREHP) has been shown t o be a protective antigen in animal models of amebic liver abscess whe n delivered by either parenteral or oral routes of immunization, and a ntibodies to SREHP can prevent amebic liver abscess in severe combined immunodeficient mice. To identify B cell epitopes of the SREHP molecu le that could serve as the basis for a peptide-based vaccine, we synth esized overlapping peptides spanning the amino acid sequence of SREHP, and looked at the reactivity of serum samples from five individuals w ith amebic liver abscess to the overlapping peptides. We found that mo st of the epitopes recognized by serum samples from patients with ameb ic liver abscess map to the hydrophilic dodecapeptide or octapeptide r epeats of SREHP, but there was no universal epitope recognized by all five serum samples. In addition, we show that synthetic peptides that include the epitopes of SREHP recognized in the mapping study are immu nogenic in animals and can generate antibodies that recognize SREHP.