Análise e identificação de peptídeos como possíveis candidatos para o desenvolvimento de vacinas e métodos diagnóstico da leptospirose

Abstract

Leptospirosis is caused by bacteria of the genus Leptospira and is responsible for about 60 thousand deaths annually worldwide. The infection occurs through direct or indirect contact with contaminated animals' urine because the bacteria colonize the renal tubes e are excreted in the urine, which can cause renal insufficiency. The bacteria can also spread into the lungs and liver, causing fever, lungs hemorrhage, and hepatic insufficiency with lethality in about 15% of cases. Nowadays, there are about 13 pathogenic species of Leptospira with more than 200 serovars described in the literature. This diversity hinders vaccine and diagnostic methods development, which could cover such variability. Thus, the study aims to check peptides' recognition capacity from Leptospira proteins by hamsters’ serum previously immunized with an anti-Leptospirosis’ vaccine with reduced LPS. To do so, seven peptides were designed and analyzed in silico, synthesized, and evaluated by the Dot Blot technique. The selected peptides were applied into a 0,45 μm nitrocellulose membrane and incubated with the serum of immunized animals to verify possible recognitions. Next, the membranes were incubated with a secondary antibody conjugated with peroxidase. The membranes were revealed using ECL kit and the chemiluminescent signal was detected by the Cambridge Uvitec. Preliminary results showed specific recognition capability of three of the seven designed peptides from Leptospira proteins. The remaining peptides did not show a detectable signal or showed possible non-specific interactions. Therefore, we concluded that the Dot Blot technique could be a simple and effective technique used to analyze and identification of epitopes and proteins able to induce antibodies in immunizations or natural infections. Besides that, the identification of peptides able to recognize specifically anti-Leptospira antibodies is a promising strategy for diagnostic test development and identification of possible candidates for vaccines development.