Evaluation of three recombinant Leishmania infantum antigens in human and canine visceral leishmaniasis diagnosis

• Published in: Acta tropica Vol. 137; pp. 25 - 30
• Main Authors: Fonseca, Aliani Moura, Faria, Angélica Rosa, Rodrigues, Fernandes Tenório Gomes, Nagem, Ronaldo Alves Pinto, Magalhães, Rubens Daniel Miserani, Cunha, João Luís Reis, Bartholomeu, Daniella Castanheira, de Andrade, Hélida Monteiro
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2014
• Subjects: Animals; Antibodies, Protozoan - blood; Antigens; Antigens, Protozoan - genetics; Brazil; Carrier State - diagnosis; Carrier State - veterinary; Diagnosis; Dog Diseases - diagnosis; Dogs; Enzyme-Linked Immunosorbent Assay - methods; Escherichia coli; Escherichia coli - genetics; Gene Expression; Humans; Leishmania infantum; Leishmania infantum - genetics; Leishmania infantum - immunology; Leishmaniasis, Visceral - diagnosis; Leishmaniasis, Visceral - veterinary; Recombinant proteins; Recombinant Proteins - genetics; Sensitivity and Specificity; Serologic Tests - methods; Visceral leishmaniasis; Brazil; Antigens; Leishmania infantum; Diagnosis; Visceral leishmaniasis; Recombinant proteins
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2014.04.028

Three recombinant Leishmania infantum antigens were produced in Escherichia coli. They were tested in ELISA to visceral leishmaniasis diagnosis, showing encouraging results with canine samples. •We tested 3 Leishmania proteins unknown function in visceral leishmaniasis diagnosis using ELISA.•Antigen C9 showed great performance in human diagnosis.•Antigen C8 showed poor performance in human diagnosis, but detected infected dogs.•Asymptomatic dogs were satisfactorily detected by the investigated antigens.•Our work contributes with leishmaniasis control based in a more accurate diagnosis. Visceral leishmaniasis (VL) is a neglected disease and is fatal if untreated. Dogs serve as reservoirs for Leishmania infantum (syn. L. chagasi) due to their susceptibility to infection and high skin parasitism. Therefore, VL control in Brazil involves the elimination of seropositive dogs, among other actions. However, the most frequently used serological tests have limitations regarding sensitivity and specificity. In this study, we have selected three Leishmania antigens (C1, C8 and C9) and have produced them as recombinant proteins using pET-28a-TEV vector and Escherichia coli BL-21 as expression system. When tested in ELISA with human samples, the C9 antigen was the one showing the most promising results, with 68% sensitivity and 78% specificity. When testing canine samples, the C1, C8 and C9 antigens showed a sensitivity range from 70% to 80% and specificity range from 60% to 90%. The C1 antigen presented higher sensitivity (80%) and the C8 antigen presented higher specificity (90%). Due to it, we decided to mix and test C1 and C8 antigens together, resulting in the C18 antigen. The mix also yielded high percentages of detected symptomatic and asymptomatic dogs however it did not improve the performance of the diagnostic. Comparison of our tests with the tests recommended by the Brazilian Ministry of Health revealed that our antigens’ sensitivities and the percentage of detected asymptomatic dogs were much higher. Our results suggest that the C1, C8, C18 and C9 recombinant proteins are good antigens to diagnose canine visceral leishmaniasis and could potentially be used in screening tests. To diagnose human visceral leishmaniasis, the C9 antigen presented reasonable results, but more optimization must be performed for this antigen to provide better performance.