RESUMEN
Leptospirosis is caused by bacteria of the genus Leptospira. More than 500,000 severe cases are reported annually, with a mortality rate of over 10%. Infection in humans usually occurs through direct or indirect contact with the urine of carrier animals. Reservoir animals do not present clinical signs of the acute disease, but renal colonization by Leptospira is frequent. Leptospirosis affects populations in both urban and rural areas, especially in tropical and subtropical climates areas. Conditions such as heavy rainfall and areas without sanitary services, favor the incidence and spread of leptospirosis. Humans are accidental hosts and may have asymptomatic manifestations or severe disease leading to death. The Leptospira genus harbors a wide variety of serovars, hindering the development of vaccine and early diagnosis, and consequently the control of the disease. The aim of this study was to identify Leptospira protein peptides conserved with immunogenic potential and capacity for recognition by antibodies present in human sera from diagnosed patients with leptospirosis. For this, five peptides were designed and selected in silico and analyzed by Dot-blot technique. The results demonstrated the five peptides were recognized by antibodies from human serum. The Pep 9 was recognized by two sera samples. In this study, the immunoinformatics tools were important to help in the peptides screening, and optimizing time and reducing financial expenses. The Dot-blot technique indicate to be effective for testing the recognition of epitopes that may induce an immune system response. The identification of peptides that are recognized by antibodies is a promising approach for the development of vaccines and diagnostic method for leptospirosis.
A leptospirose é causada por bactérias do gênero Leptospira. Anualmente são relatados mais de 500.000 casos graves, apresentando uma taxa de mortalidade superior a 10%. A infecção em humanos geralmente ocorre por contato direto ou indireto com a urina de animais portadores. Os humanos são hospedeiros acidentais e podem ter manifestações assintomáticas até condições graves evoluindo para óbito. Condições climáticas como chuvas intensas e condições sociais como áreas sem serviços sanitários, favorecem a incidência e disseminação da leptospirose. O gênero Leptospira alberga grande variedade de sorovares dificultando o desenvolvimento de uma vacina eficiente e diagnóstico precoce, e consequentemente o controle da doença. O presente estudo visa desenhar e identificar peptídeos de proteínas de Leptospira com potencial imunogênico e com capacidade de reconhecimento por anticorpos presentes em soros de pacientes diagnosticados com leptospirose. Para isso, cinco peptídeos foram desenhados e analisados in silício e por técnica de Dot-blot. Os resultados demonstraram a capacidade de reconhecimento dos cinco peptídeos testados frente às amostras de soro humano. Nesse estudo o uso da imunoinformática foi importante para auxiliar na escolha dos peptídeos, otimizando o tempo e diminuindo gastos financeiros. A técnica Dot-blot se mostrou eficaz para analisar o reconhecimento dos peptídeos de proteínas de Leptospira por anticorpos presentes nas amostras de soros analisadas. A identificação de peptídeos que sejam reconhecidos por anticorpos, é uma abordagem promissora para o desenvolvimento de vacinas e método de diagnostico para a leptospirose.
RESUMEN
Leptospirosis is a public health concern with lethality around 15% of the total cases. The current vaccines against Leptospira infection based on bacterins have several limitations, which require urgent development of new ones. In this context, groundbreaking approaches such as peptide-vaccines could be used to come around with promising results. Our goal was to identify conserved and immunogenic epitopes from the lipoprotein LruC that could interact with Major Histocompatibility Complex (MHC) I and II. LruC is a conserved lipoprotein expressed during leptospirosis that is considered among vaccine candidates and can be used as source for development of peptide-based vaccines. We searched for peptides that would be recognized by antibodies from either serum of hamsters previously immunized with low-LPS bacterin vaccines or from serum of patients diagnosed with leptospirosis. Immuno properties of seven peptides from LruC protein were evaluated in silico and by Dot Blot assay, and validate by ELISA. Preliminary results pointed one promising peptide that was recognized by the sera. In conclusion, the immunoinformatic approach helps the search and screening of peptides, while the Dot Blot assay, a simple and effective tool, helps to test and validate them. Thus, these prospective techniques together were validated to identify and validate potential peptides for further investigation as peptide-based vaccines or diagnostic methods.
