Análise comparativa in sílico de novos peptídeos derivados de proteínas imunodominantes de Toxoplasma gondii, com potencial para serem aplicados como ferramentas para o diagnóstico da toxoplasmose humana

Abstract

Serological tests for the diagnosis of Toxoplasma gondii infection have limitations in differentiating acute from chronic infection, which is important in determining the clinical management and treatment of pregnant women and immunocompromised individuals with toxoplasmosis. Here, an in silico analysis was performed to characterize immunogenic epitopes of SAG1, SAG2A, GRA1, GRA2, GRA3, GRA5, GRA6, GRA7, MAG1, BSR4, and CCp5A proteins that may emerge as alternatives to improve the diagnosis of toxoplasmosis. Once the protein sequences were retrieved from the Toxodb database, different parameters were calculated including physicochemical characteristics, accessibility values, and antigenicity. Multiple sequence alignment, 3D structure modeling, refinement, and validation were also performed among all 11 peptides. Considering the results from the combination of all parameters analyzed, it can be concluded that the peptides of SAG1, GRA3, and BSR4 proteins were found to be stable, hydrophilic, with significant antigenicity values, and accessibility on the protein surface. Thus, the use of these peptides may suggest alternative measures for the design and standardization of new immunodiagnostic assays for toxoplasmosis.