ABSTRACT
Serological diagnosis of Trypanosoma cruzi infection is hampered by issues related to test specificity due to the cross-reactivity of most antigens with proteins of related parasites such as Leishmania spp. The recombinant calflagins are considered relevant antigens for the diagnosis of infection by Trypanosoma cruzi. In the present work, we describe two genes coding for putative calflagins in Leishmania major with the N-terminal moieties presenting high similarity with T. cruzi genes. This fact raised questions about their role in some cross-recognition of this antigen by sera from Leishmania spp.-infected individuals. The complete T. cruzi calflagin and two fragments of the protein, consisting of 146 amino acids of the N-terminal and 65 amino acids of the C-terminal regions, were expressed and evaluated against a panel of sera, which included well-characterized samples from T. cruzi, and Leishmania-infected patients. We were able to show that sera from Leishmania (Viannia) braziliensis-infected individuals recognized the recombinant full-length calflagin. Both the N-terminal and the complete protein presented the same high sensitivity (98.5% of sera from T. cruzi-infected patients was detected) but different specificities (94% and 98%, respectively, when evaluated against sera from people not infected by T. cruzi, including 15 sera from people infected with L. braziliensis). The C-terminal fragment presented low sensitivity (70%) but 100% specificity. We propose the use of these antigens in two sequential assays to optimize the serological diagnosis of T. cruzi infection in humans in geographic areas where Leishmania spp. infection is coendemic.
Subject(s)
Calcium-Binding Proteins/biosynthesis , Chagas Disease/diagnosis , Protozoan Proteins/biosynthesis , Trypanosoma cruzi/chemistry , Amino Acid Sequence , Animals , Antigens, Protozoan/biosynthesis , Antigens, Protozoan/chemistry , Calcium-Binding Proteins/chemistry , Calcium-Binding Proteins/genetics , Enzyme-Linked Immunosorbent Assay/methods , Escherichia coli/metabolism , Hemagglutination Tests/methods , Humans , Molecular Sequence Data , Protein Engineering , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , Recombinant Proteins/biosynthesis , Sensitivity and Specificity , Sequence AlignmentABSTRACT
In the present work we propose a simple method for affinity purification of the 67-kDa lectin-like glycoprotein (LLGP-67) from Trypanosoma cruzi, the causative agent of Chagas' disease. The LLGP-67, which presents galactose binding activity and participates in the host cell recognition process, was previously purified by methods based on its interaction with galactose residues on erythrocytic membranes. We describe herein results showing that this protein can be purified from T. cruzi in a direct way using non-derivatized agarose as a chromatographic ligand. We also demonstrate the relevance of LLGP-67 as an antigen for human diagnosis of chagasic infection. Sensitivity and specificity for this antigen were calculated, being 98 and 98.11% respectively.
Subject(s)
Antigens, Protozoan/isolation & purification , Chagas Disease/diagnosis , Lectins/isolation & purification , Protozoan Proteins/isolation & purification , Trypanosoma cruzi/chemistry , Animals , Antigens, Protozoan/analysis , Antigens, Protozoan/immunology , Chagas Disease/parasitology , Chromatography, Affinity , Chromatography, Agarose , Enzyme-Linked Immunosorbent Assay , Female , Galactose/metabolism , Humans , Immune Sera , Lectins/analysis , Lectins/immunology , Protozoan Proteins/analysis , Protozoan Proteins/immunology , Rabbits , Trypanosoma cruzi/immunologyABSTRACT
Meeting of the Biotechnology Subcommittee Advisory Committee on Health Research in Buenos Aires, Argentina on April 16-19, 1996
Meeting of the Advisory Committee on Health Research, 31. Pan American Health Organization; Jul. 15-17, 1996
Subject(s)
Biotechnology , Health Services ResearchABSTRACT
Meeting of the Biotechnology Subcommittee Advisory Committee on Health Research in Buenos Aires, Argentina on April 16-19, 1996
Reunión del Comité Asesor de Investigaciones en Salud, 31. Organizacion Panamericana de la Salud; Jul. 15-17, 1996
