UTILITY OF RECOMBINANT FLAGELLAR CALCIUM-BINDING PROTEIN FOR SERODIAGNOSIS OF TRYPANOSOMA-CRUZI INFECTION

The protozoan Trypanasoma cruzi is the causative agent of Chagas' dise ase, a major public health problem in Latin America and of growing con cern in the United States as the number of infected immigrants increas es, There is currently no testing of U.S. blood products for T. cruzi infection, and the best tests available, although highly sensitive, ar e not of high enough specificity to be useful for widespread screening of the blood supply in this country. Among the parasite antigens dete cted by sera of infected humans and mice, those in the range of 24 to 26 kDa are particularly reactive. With an aim of developing a sensitiv e, specific, recombinant antigen-based serologic test for T. cruzi inf ection, we used two antibody reagents specific for these 24- to 26-kDa antigens to isolate cDNA clones from a T. cruzi expression library. O ne clone was found to encode a previously characterized T. cruzi antig en, a 24-kDa flagellar calcium-binding protein (FCaBP), Recombinant FC aBP was found to be a sensitive, specific reagent for distinguishing T . cruzi-infected individuals from uninfected persons, and it therefore could potentially be used for screening purposes, especially if combi ned with other recombinant T. cruzi antigens that have similarly high degrees of diagnostic sensitivity and specificity.