Mimotopos de Leishmania infantum e fago-ELISA como ferramentas para um sorodiagnóstico sensível e específico da leishmaniose visceral humana

Abstract

Visceral Leishmaniasis (VL) is an anthropozoonosis that represents one of the biggest public health problems in the world. As the clinical presentation of VL lacks specificity, laboratory testing is necessary for confirmation of infection and establishment of appropriate treatment. Its diagnosis must have a high sensitivity and specificity (> 95%) as VL is fatal and because the treatments currently available present a high toxicity. The serological methods used to diagnose VL are minimally invasive, but currently available limitations include identifying antibodies in treated patients even after long periods of time and not identifying patients with relapses. Thus, the search for new antigens capable of overcoming the limitations of current serological tests is relevant. Thus, the objective of this study was to select fused epitopes with bacteriophages to be used in the serodiagnosis of human VL. In this work, clones of bacteriophages expressing exogenous peptides of interest were selected against antibodies from healthy individuals living in endemic and non-endemic areas for VL, from patients with Chagas' disease and from people with active VL. Eight phage clones were selected after the cycles of bio-panning, and their reactivity against a human serological panel was evaluated in a phage-ELISA assay. The wildtype phage (without the exogenous peptide) and the immunochromatographic test based on the K39 recombinant protein were used as controls. The results demonstrate that all eight clones showed an excellent performance to serologically identify patients with VL of the other groups analyzed. Therefore, new antigens potentially capable of being used in a highly specific and sensitive serodiagnosis for VL were found.