Use of full-length recombinant calflagin and its c fragment for improvement of diagnosis of Trypanosoma cruzi infection.
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.
Marcipar
Iván S
IS
Instituto de Tecnología Biológica, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
Roodveldt
Cintia
C
Corradi
Gerardo
G
Cabeza
María L
ML
Brito
Maria Edileuza F
ME
Winter
Lucile M Floeter
LM
Marcipar
Alberto J
AJ
Silber
Ariel M
AM
D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D014355:Chagas Disease / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism; D006386:Hemagglutination Tests / Q000379:methods; D006801:Humans; D008969:Molecular Sequence Data; D015202:Protein Engineering; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D014349:Trypanosoma cruzi / Q000737:chemistry*
D000953:Antigens, Protozoan; D002135:Calcium-Binding Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C061478:flagellar calcium-binding protein, Trypanosoma cruzi