Experimental Evidence for Limited Virulence of .

Tuberculosis remains a public health problem and a main cause of death to humans. Both and cause tuberculosis. In contrast to , which is geographically spread, is restricted to West Africa. Differences have also been found in the growth rate and type of disease caused by , globally suggesting an attenuation of this bacteria. In this study, we used the mouse model of infection to follow the dynamics of infection in terms of bacterial burdens and tissue pathology, as well as the immune response triggered. Our findings support a lower virulence of as compared to , including in mice lacking IFN-γ, a major protective cytokine in tuberculosis. Furthermore, the lung immune response triggered by infection in wild-type animals was characterized by a discrete influx of leukocytes and a modest transcriptional upregulation of inflammatory mediators. Our findings contribute to elucidate the pathogenesis of , supporting the hypothesis that this is an attenuated member of the tuberculosis-causing bacteria. Understanding the biology of and how it interacts with the host to establish infection will have implications for our knowledge of TB and for the development of novel and better tools to control this devastating disease.