Anticorpos contra Toxoplasma gondii e Sarcocystis spp. produzidos por infecção experimental em roedores: caracterização e avaliação de reatividade cruzada com protozoários correlatos

Abstract

Toxoplasma gondii and Sarcocystis spp. are cyst-forming parasites of the Apicomplexa phylum excreted by Didelphis spp. While T. gondii is widespread in all regions of the world, infecting several species of mammals and birds, Sarcocystis spp. excreted by opossums are limited to the Americas, accompanying the distribution area of their definitive hosts. Improvement of the serological diagnosis for both parasite genera is essential, aiming both to identify the infective stage involved in cases of human toxoplasmosis, and to evaluate the possibility of cross-reactivity between Sarcocystis spp. phylogenetically correlated. The aims of this study were to characterize monoclonal antibodies against sporozoites of T. gondii with antigen of different stages of the parasite and other related-coccidia; to evaluate the use of gerbil as an experimental host of Sarcocystis falcatula-like strain isolated in Bahia, and to investigate the possible serologic cross-reactivity using Sarcocystis neurona and S. falcatula like antigens. One of the monoclonal antibodies (G1/19) recognized only T. gondii sporozoite antigen, while the other (K3/7-13) identified tachyzoite and sporozoite proteins. The gerbils were not susceptible to infection by S. falcatula-like, but seroconverted and showed cross reactivity with S. neurona antigen on Immunoblot. These findings indicate that the monoclonal G1/19 is promising for the development of a specific diagnosis for exposure to T. gondii oocysts, as well that cross-reactive occurs between S. falcatula-like and S. neurona in Immunoblot, impacting the interpretation of serological results for this last parasite.