Desenvolvimento de um ELISA com a proteína recombinante LigBrep para o diagnóstico de leptospirose

Abstract

Leptospirosis is a zoonosis caused by infection of pathogenic spirochetes of the genus Leptospira. It possesses as carriers of the bacterium, wild and domestic animals. Humans are considered accidental hosts because they contract leptospirosis from a source of animal infection, mainly through the canines. More than 1 million severe cases of leptospirosis worldwide are reported annually, resulting in approximately 59,000 deaths. The standard diagnostic test for leptospirosis is the Micro Agglutination Test (MAT). However, the MAT has limitations such as difficulty in execution, since it requires the cultivation of live strains, it is a subjective test and has low sensitivity in the acute phase of the disease. Thus, there is a need to develop new diagnostic tests that are faster and more effective. The objective of this study was to develop an enzyme-linked immunosorbent assay (ELISA) based on the detection of IgG and IgM antibodies in human and canine sera using rLigBrep and rLipL32 as the antigen for the diagnosis of human and canine leptospirosis. In the analysis of the individual human sera with IgM antibody the sensitivity and specificity were 87.0 and 100%, respectively. With the IgG antibody the sensitivity of the test was 92.7% and the specificity was 71.4%. In the tests with canine sera, IgG antibody and rLigBrep the results were 99.2 and 95.5% sensitivity and specificity, respectively. Evaluating the same canine sera with the rLipL32 protein, the sensitivity was 90% and specificity was 91%. The Kappa analysis of the canine tests with rLigBrep was 0.94 and with rLipL32 it was 0.790, demonstrating high agreement with the standard diagnostic test. Thus, the ELISA test with the rLigBrep protein presents more promising results than the rLipL32 protein, being an important protein in the aid for the development of new diagnostic tests for leptospirosis.