INDUCTION OF HUMORAL AND CELLULAR IMMUNE-RESPONSES BY VACCINATION WITH MYCOBACTERIUM-TUBERCULOSIS ANTIGEN-85 DNA

DNA vaccines have been demonstrated to be effective in inducing protec tive cell-mediated immune responses in animal models of infectious dis ease. In order to investigate this approach for potential use as a vac cine for tuberculosis, DNA constructs encoding Mycobacterium tuberculo sis antigen 85A (Ag85A) were prepared. Expression of Ag85A in mammalia n cells was demonstrated by transient transfection of cells in vitro. Intramuscular injection of Ag85A DNA vaccines resulted in the generati on of anti-Ag85A antibodies and robust cell-mediated immune responses, as measured by lymphoproliferation of spleen cells in vitro upon spec ific antigen restimulation, leading to protection in animal challenge models. Therefore, the technique of DNA vaccination is effective in in ducing relevant immune responses for protection against tuberculosis a nd may be used to identify the protective antigens of M. tuberculosis.