Immunogenicity and efficacy of a tuberculosis DNA vaccine encoding the components of the secreted antigen 85 complex.

&lt;p&gt;BALB/c and C57BL/6 mice were injected intramuscularly with plasmid DNA encoding the three components of the immunodominant 30-32 kDa antigen 85 complex (Ag85A, Ag85B, and Ag85C) from Mycobacterium tuberculosis culture filtrate, in order to investigate the utility of nucleic acid vaccination for induction of immune responses against mycobacterial antigens. Ag85A and Ag85B encoding plasmids induced a robust Th1-like response towards native Ag85, characterized by elevated levels of interleukin (IL)-2, interferon-gamma, and TNF-alpha. Levels of IL-4, IL-6, and IL-10 were low or undetectable. Plasmid encoding Ag85C was not effective. Cytotoxic T cell activity was also generated in in vitro restimulated splenocyte cultures from Ag85A and Ag85B DNA vaccinated mice. Finally, Ag85A and Ag85B DNA vaccination conferred significant protection against mycobacterial replication in lungs from B6 mice, subsequently challenged. Therefore, this technique may be useful for the definition of protective antigens of M. tuberculosis and the development of a more effective tuberculosis vaccine.&lt;/p&gt;</p

Induction of immunity by DNA vaccination: application to influenza and tuberculosis.

&lt;p&gt;DNA vaccination is an effective means of inducing both humoral and cell-mediated immunity in animal models of infectious disease. Presented here are data generated in two distinct disease models; one viral (influenza) and one bacterial (tuberculosis). Specifically, plasmid DNA encoding an influenza virus antigen (nucleoprotein; NP) and a Mycobacterium tuberculosis antigen (antigen 85; Ag85) were prepared and tested as DNA vaccines in mice. In both cases, high titer antibody responses and robust cell-mediated immune responses were induced against the respective antigens. With respect to the latter, lymphocyte proliferation, Th1-type cytokine secretion, and cytotoxic T lymphocyte responses were observed upon restimulation with antigen in vitro. Furthermore, protective efficacy in animal challenge models was demonstrated in both systems. The data support the hypothesis that DNA vaccination will prove to be a broadly applicable technique for inducing immunity against various infectious diseases.&lt;/p&gt;</p

Immunogenicity and protective efficacy of a tuberculosis DNA vaccine.

&lt;p&gt;Tuberculosis is the most widespread and lethal infectious disease affecting humans. Immunization of mice with plasmid DNA constructs encoding one of the secreted components of Mycobacterium tuberculosis, antigen 85 (Ag85), induced substantial humoral and cell-mediated immune responses and conferred significant protection against challenge with live M. tuberculosis and M. bovis bacille Calmette-Guérin (BCG). These results indicate that immunization with DNA encoding a mycobacterial antigen provides an efficient and simple method for generating protective immunity and that this technique may be useful for defining the protective antigens of M. tuberculosis, leading to the development of a more effective vaccine.&lt;/p&gt;</p