SCHISTOSOMA-MANSONI HEXOKINASE - CDNA CLONING AND IMMUNOGENICITY STUDIES

DNA encoding a Schistosoma mansoni hexokinase (SHEX) was amplified fro m cDNA by the polymerase chain reaction using opposing oligonucleotide primers designed to hybridize with two short segments of hexokinase c oding sequences that an well-conserved through evolution. The resultin g DNA fragment was then used as a probe to identify a full-length hexo kinase cDNA clone. SHEX cDNA encodes a 50-kDa protein that is approxim ately 46% homologous to rat hexokinase, 40% to rat glucokinase, and 34 % to yeast hexokinase A. SHEX coding DNA was expressed within Escheric hia coli cells and the 50-kDa recombinant product (rSHEX) was partiall y purified. Mice repeatedly immunized with rSHEX produced antibodies w hich recognize rSHEX but this offered no significant protection agains t subsequent cercarial challenge. On Western blots. rSHEX is weakly re cognized by antisera against rat brain hexokinase but not by sera from three strains of mice experimentally infected with S. mansoni parasit es or from numerous human schistosomiasis patients. Thus, unlike other reported S. mansoni glycolytic enzymes, hexokinase appears to be poor ly immunogenic during schistosome infection and of limited potential a s a vaccine candidate. (C) 1995 Academic Press, Inc.