title: Glycoconjugates of Trypanosoma cruzi: a 74 kD antigen of trypomastigotes specifically reacts with lytic anti-alpha-galactosyl antibodies from patients with chronic Chagas disease.
abstract: Protective, lytic antibodies are believed to be correlated with active Trypanosoma cruzi infection. In patients with chronic infection, antibodies lysing trypomastigote forms recognize chiefly alpha-galactosyl structures at the parasite surface. The target molecules on cell-derived trypomastigotes that react with anti-alpha-galactosyl antibodies (anti-Gal) from patients with chronic Chagas disease were investigated. Glycoconjugates were isolated from trypomastigotes and shown to absorb purified Chagasic (Ch) anti-Gel effectively as well as lytic antibodies from Ch sera. Active fractions were F2 (74 kD and 95.6 kD) and F3 (120-200 kD). A differential reactivity with antibodies from untreated Ch patients (trypanolytic) and from treated, presumably cured, individuals (not trypanolytic) was evident using F2 and F3 antigenic fractions. No cross-reactivity with heterologous sera (other infections) was observed. The F2 glycoconjugate (mostly 74 kD) can be used in the diagnosis of active Chagas infection, replacing the quantitative determination of complement-mediated lysis. With the present sample of patients' sera and normal human sera, it showed 100% sensitivity and specificity.
authors.affiliation: Department of Microbiology, Immunology, and Parasitology, Escola Paulista de Medicina, São Paulo, Brazil.
authors.forename: I C
authors.initials: IC
authors.lastname: Almeida
authors.forename: G M
authors.initials: GM
authors.lastname: Krautz
authors.forename: A U
authors.initials: AU
authors.lastname: Krettli
authors.forename: L R
authors.initials: LR
authors.lastname: Travassos
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000737:chemistry; D002240:Carbohydrate Sequence; D014355:Chagas Disease / Q000276:immunology*; D002908:Chronic Disease; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005690:Galactose / Q000276:immunology; D006001:Glycoconjugates / Q000737:chemistry / Q000276:immunology; D006801:Humans; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry / Q000276:immunology; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D006001:Glycoconjugates; D009844:Oligosaccharides; D005690:Galactose