Infection of Adipose Tissues.

Adipose tissues were shown to host which is persisting inside mature adipocytes. It remains unknown whether this holds true for , a rare representative of the complex responsible for lymphatic and pulmonary tuberculosis. Here, we infected primary murine white and brown pre-adipocytes and murine 3T3-L1 pre-adipocytes and mature adipocytes with and as a positive control. Both mycobacteria were able to infect 18-22% of challenged primary murine pre-adipocytes; and to replicate within these cells during a 7-day experiment with the intracellular inoculums being significantly higher in brown than in white pre-adipocytes for ( = 0.02) and ( = 0.03). Further infection of 3T3-L1 mature adipocytes yielded 9% of infected cells by and 17% of infected cells by ( = 0.001). Interestingly, replicated and accumulated intra-cytosolic lipid inclusions within mature adipocytes over a 12-day experiment; while stopped replicating at day 3 post-infection. These results indicate that brown pre-adipocytes could be one of the potential targets for complex mycobacteria; and illustrate differential outcome of complex mycobacteria into adipose tissues. While white adipose tissue is an unlikely sanctuary for , it is still an open question whether and could persist in brown adipose tissues.