CD271(+) bone marrow mesenchymal stem cells may provide a niche for dormant Mycobacterium tuberculosis.

Mycobacterium tuberculosis ( Mtb ) can persist in hostile intracellular microenvironments evading immune cells and drug treatment. However, the protective cellular niches where Mtb persists remain unclear. We report that Mtb may maintain long-term intracellular viability in a human bone marrow (BM)–derived CD271 + /CD45 − mesenchymal stem cell (BM-MSC) population in vitro. We also report that Mtb resides in an equivalent population of BM-MSCs in a mouse model of dormant tuberculosis infection. Viable Mtb was detected in CD271 + /CD45 − BM-MSCs isolated from individuals who had successfully completed months of anti- Mtb drug treatment. These results suggest that CD271 + BM-MSCs may provide a long-term protective intracellular niche in the host in which dormant Mtb can reside.