Identification and characterization of Schistosoma mansoni p17.7, a cyclophilin

Antibodies affinity purified against tegumental components of schistosomula were used to screen a Schistosoma mansoni λgt11 adult worm cDNA expression library. One of the reactive clones was determined by sequence analysis to encode a protein homologous to cyclophilins of other species, in particular cyclophilin A. The 0.8-kb cDNA clone contained an open reading frame of 483 nucleotides which corresponds to a translation product of 161 amino acids with a deduced molecular size of 17.7 kDa. We have chosen to designate this clone as S. mansoni p17.7 (Smp17.7). The overexpressed and purified recombinant Smp17.7 (rSmp17.7) was demonstrated to possess peptidylprolyl cis-trans isomerase (PPIase) or rotamase activity typical of cyclophilins. Western blot analysis of Nonidet P-40 and a total soluble extract of adult schistosomes probed with affinity-purified antisera to rSmp17.7, demonstrated the presence of this protein in the parasite. Immunofluorescence studies using the purified antisera indicates a localization in various tissues including the tegument and the gut. As cyclophilin is able to interact with cyclosporin A (CsA), which has been shown to be antischistosomal in mice infected with S. mansoni, the characterization of this S. mansoni cyclophilin homologue may allow a better understanding of the schistosomicidal nature of cyclosporin A and lead to a novel strategy of therapy for schistosomiasis.