Avaliação de vacinas recombinantes e bacterinas compostas pelas proteínas ROP2 de Neospora caninum e de ROP2 associada a porção B da toxina termo lábil de Escherichia coli

Abstract

Neospora caninum is an obligate intracellular protozoan etiological agent of neosporosis, major parasitic disease responsible for abortion in cattle worldwide. Several prophylactic measures against neosporosis in farm animals have been studied aiming to reduce the economic losses caused by this disease. An alternate control method would be through vaccination immunoprophylaxis. This study aimed to evaluate the immune response of Swiss mice against the recombinant antigen ROP2, this fused with the B portion of the heat labile enterotoxin of Escherichia coli (LTB), expressed in E. coli in the form of bacterin or purified. The antigens were quantified by SDS-PAGE technique and characterized by Western blot. After making the vaccination of experimental animals with ROP2 and ROP2 / LTB, samples were taken of blood for evaluation of total IgG levels of antibody titers and isotypes by ELISA technique. It was observed that all the evaluated antigens are able to stimulate the production of antibodies, and vaccines consisting of purified recombinant proteins generated a higher total IgG response (p <0.05) recombinant bacterins. These vaccines had titers higher antibodies obtained by the vaccine composed by the bacterins. The analysis of the isotypes both vaccines composed of purified recombinant proteins stimulated levels of IgG1 and IgG2a, wherein the antigen ROP2 generated higher levels of IgG2a and ROP2 antigen / LTB higher IgG1 levels. However, in this study it can be concluded that vaccination with the purified recombinant antigens were more effective in stimulating the humoral immune response compared bacterins which these antigens have stimulated the immune response for either a Th1 pathway as for Th2 pathway, and the presence of ROP2 generated response modulation for a Th1 pathway, unlike ROP2 / LTB antigen that due to the presence of LTB molecule modulates the immune response for a Th2 pathway, promoting a better balance of the immune response between Th1 pathways and Th2.