Development and Application of an ELISA Assay Using Excretion/Secretion Proteins from Epimastigote Forms ofT. cruzi(ESEA Antigens) for the Diagnosis of Chagas Disease

Abstract

An indirect enzyme-linked immunoabsorbent assay (ELISA) forTrypanosoma cruziwas developed using epimastigote secretion/excretion proteins (ESEA antigens) obtained from axenic culture supernatants. A panel of 120 serum samples from subjects with confirmed Chagas disease(n=50), healthy controls(n=50), and patients with other parasitic diseases(n=20)was used to evaluate the new ESEA-based ELISA (ELISAESEA). This new test had excellent sensitivity (98%) and acceptable specificity (88%). Cross-reactivity was observed largely in sera from subjects withLeishmaniaandAscarisinfections. Using Western blotting and epimastigotes from two distinctT. cruziisolates, several polypeptide bands with molecular masses ranging from 50 to 220 kDa were detected in pooled chagasic sera. However, the band pattern for each isolate was different. These data suggest that an inexpensive and technically simple ELISA based on ESEA antigens is a promising new tool for the diagnosis of Chagas disease.