Mycobacteria-Specific T Cells Are Generated in the Lung During Mucosal BCG Immunization or Infection With Mycobacterium tuberculosis
Juan I. Basile, Ruining Liu, Wenjun Mou, Yu Gao, Berit Carow, Martı́n E. Rottenberg
Abstract
Specific T cell responses are central for protection against infection with M. tuberculosis. Here we show that mycobacteria-specific CD4 and CD8 T cells accumulated in the lung but not in the mediastinal lymph node (MLN) at different time points after M. tuberculosis infection or BCG immunization. Proliferating specific T cells were found in the lung after infection and immunization. Pulmonary, but not MLN-derived CD4 and CD8 T cells, from M. tuberculosis-infected mice secreted IFN- after stimulation with different mycobacterial peptides or PPD. Mycobacteria-specific resident memory CD4 and CD8 T cells (TRM) expressing PD-1 accumulated in the lung after aerosol infection and intratracheal (i.t.) -but not subcutaneous (s.c.)- BCG immunization. Chemical inhibition of recirculation indicated that TRM were generated in the lung after BCG i.t. immunization. In summary, mycobacteria specific-TRM accumulate in the lung during i.t. but not s.c. immunization or M. tuberculosis infection. Collectively our data suggests that priming, accumulation and/ or expansion of specific T cells during BCG immunization and M. tuberculosis infection occurs in the lung.