Bifidobacterium longum modulates pulmonary immune response in obese mice infected with Mycobacterium tuberculosis

Tuberculosis (TB) is a heterogeneous disease that is influenced by genetic factors of the infected host, the mycobacterial strain, social factors, and comorbidities. Among the comorbidities, obesity and diabetes increase susceptibility to the development of the disease through the exacerbation of the inflammatory response arising from intestinal dysbiosis. We hypothesize that the probiotic Bifidobacterium longum attenuates lung inflammation and infection progression in the comorbidity obesity and TB. In this context, the aim of the present study was to investigate the role of B. longum in the comorbidity obesity and TB. Female C57BL/6 mice were fed with High Fat Diet (HFD) for 8 weeks and infected with Mycobacterium tuberculosis. Four weeks after infection, mice were treated with the B. longum daily for 4 weeks. Although no change was found in pulmonary bacterial load evaluated by CFU (Colony Form Units) count, HFD group treated with the probiotic (HFD+probiotic group) showed an increase in interstitial macrophages (CD11b- SiglecF+ cells) expressing iNOS or arginase, as well as Th17 cells (CD4+IL-17+ cells), CD8+IFN-gamma+ lymphocytes and Treg cells (CD4+Foxp3+ cells) compared to non-treated group (HFD group). These preliminary findings suggest that B. longum modulates the pulmonary immune response in the obesity and TB comorbidity.

Financial Support: FAPESP grant 2017/21629-5 and FAPESP grant 2024/05569-6