Immunogenicity of a Recombinant Mycobacterium smegmatisVaccine Expressing the Fusion Protein CMX in Cattle from Goiás State,Brazil

[摘要] References(53)This study aimed to evaluate the immunogenicity of a recombinantMycobacterium smegmatis vaccine expressing the CMX fusion proteincomposed of immunodominant epitopes Ag85C, MPT51 and HspX of Mycobacteriumtuberculosis, which are important mycobacteria virulence factors. A group ofNelore heifers that were 10 to 12 months of age and negative for the tuberculin skin test(TST) were immunized with four doses of the recombinant vaccine mc2-CMX(M. smegmatis-Ag85C-MPT51-HspX) during a period of oneyear. Before each immunization, blood was collected to obtain sera for antibody analysis.Serological analysis demonstrated that mc2-CMX was able to induce a humoralresponse with increased levels of specific IgG antibodies against CMX, despite minimumantibody levels being detected for individual Ag85C, MPT51 or HspX recombinant antigens.However, there was no significant increase in specific CD4+ IFN-γ-positive Tcells. Lymphadenomegaly was observed in superficial cervical lymph nodes adjacent to thesite of vaccination among mc2-CMX-vaccinated bovines, and the histopathologicalanalysis demonstrated follicular hyperplasia without inflammatory infiltrate or granulomaformation. Animals remained negative for the TST until the end of the experiments, showingno cross-reactivity with the recombinant vaccine and tuberculin proteins. We discuss thepotential of mc2-CMX to induce an immune response in cattle.

[学科分类] 兽医学

[关键词] environmental mycobacteria;immunological response;Mycobacterium bovis;public health;zoonosis