Purified excreted-secreted antigens from Trypanosoma cruzi trypomastigotes as tools for diagnosis of Chagas' disease.
There is currently no "gold standard" test for the diagnosis of late-stage Chagas' disease. As a result, protection of the blood supply in areas where Chagas' disease is endemic remains problematic. A panel of 709 serum samples from subjects with confirmed Chagas' disease (n = 195), healthy controls (n = 400), and patients with other parasitic diseases (n = 114) was used to assess enzyme-linked immunosorbent assays (ELISAs) based on a concentrated extract of excretory-secretory antigens from either Brazil or Tulahuen strain Trypanosoma cruzi trypomastigotes (total trypomastigote excretory-secretory antigens [TESAs]). The total TESA-based assays had excellent overall sensitivity (100%) and specificity (>94%), except for cross-reactivity with Leishmania-infected sera. In an attempt to increase the specificity of the assay, immunoaffinity chromatography was used to purify the TESA proteins (TESA(IA) proteins). By Western blotting, a series of polypeptide bands with molecular masses ranging from 60 to 220 kDa were recognized by pooled sera positive for Chagas' disease. An ELISA based on TESA(IA) proteins had a slightly lower sensitivity (98.6%) but an improved specificity (100%) compared to the sensitivity and specificity of the total TESA protein-based ELISAs. A 60-kDa polypeptide was identified as a major contributor to the cross-reactivity with Leishmania. These data suggest the need for field validation studies of TESA- and TESA(IA)-based assays in regions where Chagas' disease is endemic.
Berrizbeitia
Mariolga
M
McGill Center for Tropical Diseases, Montreal General Hospital, Room D7-153, Montreal, Quebec, H3G IA4 Canada.
Ndao
Momar
M
Bubis
José
J
Gottschalk
Marcelo
M
Aché
Alberto
A
Lacouture
Sonia
S
Medina
Mehudy
M
Ward
Brian J
BJ
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology* / Q000302:isolation & purification* / Q000378:metabolism; D014355:Chagas Disease / Q000175:diagnosis* / Q000276:immunology; D002846:Chromatography, Affinity / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014349:Trypanosoma cruzi / Q000276:immunology*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan