title: Purification and preliminary sequencing of Tc-45, an immunodominant Trypanosoma cruzi antigen: absence of homology with cruzipain, cruzain, and a 46-kilodalton protein.
abstract: In spite of being separated by more than 20 million years of evolution, the murine and human immune systems share extensive similarities. Thus, experimental results obtained with the murine model may have predictive value for human Chagas' disease. Challenge of the H-2 congenic mouse stains A.SW (H-2s) and A.CA (H-2f) with Trypanosoma cruzi yields different results. The A.CA animals die approximately 12 days postinfection, while A.SW mice survive indefinitely. A 45-kD protein (Tc45), an antigen differentially recognized by the A.SW strain, is present in cultured epimastigotes and blood trypomastigotes. We describe here its purification from epimastigotes. The presence of Tc45 was monitored and a single band was detected. Since the molecular weights of Tc45, cruzipain, cruzain, and a 46-kD parasite polypeptide are similar, it was important to determine if these molecules are related. A complete lack of homology was observed when the sequence of cruzain, cruzipain, and the 46-kD polypeptide were compared with the preliminary sequence of Tc45.
authors.affiliation: Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago.
authors.forename: J C
authors.initials: JC
authors.lastname: Aguillon
authors.forename: C
authors.initials: C
authors.lastname: Bustos
authors.forename: P
authors.initials: P
authors.lastname: Vallejos
authors.forename: T
authors.initials: T
authors.lastname: Hermosilla
authors.forename: A
authors.initials: A
authors.lastname: Morello
authors.forename: Y
authors.initials: Y
authors.lastname: Repetto
authors.forename: U
authors.initials: U
authors.lastname: Hellman
authors.forename: A
authors.initials: A
authors.lastname: Orn
authors.forename: A
authors.initials: A
authors.lastname: Ferreira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000302:isolation & purification*; D015153:Blotting, Western; D002852:Chromatography, Ion Exchange; D003546:Cysteine Endopeptidases / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000302:isolation & purification*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry; D015800:Protozoan Proteins / Q000737:chemistry*; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D014349:Trypanosoma cruzi / Q000737:chemistry*
chemical_list: D000953:Antigens, Protozoan; D006023:Glycoproteins; D016056:Immunodominant Epitopes; D010446:Peptide Fragments; D015800:Protozoan Proteins; D003546:Cysteine Endopeptidases; C074032:cruzain, Trypanosoma cruzi; C063214:cruzipain