Vaccine efficacy of an attenuated but persistent Mycobacterium tuberculosis cysH mutant

The emergence of drug-resistant Mycobacterium tuberculosis strains and the widespread occurrence of AIDS demand newer and more efficient control of tuberculosis. The protective efficacy of the current Mycobacterium bovis bacille Calmette-Guerin (BCG) vaccine is highly variable. Therefore, development of an effective new vaccine has gained momentum in recent years. Recently, several M. tuberculosis mutants were tested as potential vaccine candidates in the mouse model of tuberculosis. However, only some of these mutants were able to generate protection equivalent to that of BCG in mice. This study reports the vaccine potential of an attenuated 5'-adenosine phosphosulfate reductase mutant (Delta cysH) of M. tuberculosis. Immunization of mice with either BCG or Delta cysH followed by infection with the virulent M. tuberculosis Erdman strain demonstrated that Delta cysH can generate protection equivalent to that of the BCG vaccine.