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Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis (Mtb) infection with the formation of a broad range of abnormal lung lesions within a single patient. Although host–pathogen interactions determine disease outcome, they are poorly understood within individual lesions at different stages of maturation. We compared Mtb load in a tuberculoma wall and the lung tissue distant from tuberculomas in TB patients. These data were combined with an analysis of activation and bactericidal statuses of alveolar macrophages and other cell subtypes examined both in ex vivo culture and on the histological sections obtained from the same lung lesions. The expression of pattern recognition receptors CD14, CD11b, and TLR-2, transcription factors HIF-1α, HIF-2α, and NF-κB p50 and p65, enzymes iNOS and COX-2, reactive oxygen species (ROS) biosynthesis, and lipid production were detected for various lung lesions, with individual Mtb loads in them. The walls of tuberculomas with insufficient inflammation and excessive fibrosis were identified as being the main niche for Mtb survival (single or as colonies) in non-foamy alveolar macrophages among various lung lesions examined. The identification of factors engaged in the control of Mtb infection and tissue pathology in local lung microenvironments, where host–pathogen relationships take place, is critical for the development of new therapeutic strategies.

Tuberculosis (TB), with the Mycobacterium tuberculosis (Mtb) as the causative agent, remains to be a serious world health problem. Traditional methods used for the study of Mtb in the lungs of TB patients do not provide information about the number and functional status of Mtb, especially if Mtb are located in alveolar macrophages. We have developed a technique to produce ex vivo cultures of cells from different parts of lung tissues surgically removed from patients with pulmonary TB and compared data on the number of cells with Mtb inferred by the proposed technique to the results of bacteriological and histological analyses used for examination of the resected lungs. The ex vivo cultures of cells obtained from the resected lungs of all patients were largely composed of CD14-positive alveolar macrophages, foamy or not, with or without Mtb. Lymphocytes, fibroblasts, neutrophils, and multinucleate Langhans giant cells were also observed. We found alveolar macrophages with Mtb in the ex vivo cultures of cells from the resected lungs of even those TB patients, whose sputum smears and lung tissues did not contain acid-fast Mtb or reveal growing Mtb colonies on dense medium. The detection of alveolar macrophages with Mtb in ex vivo culture as soon as 16–18 h after isolation of cells from the resected lungs of all TB patients suggests that the technique proposed for assessing the level of infection in alveolar macrophages of TB patients has higher sensitivity than do prolonged bacteriological or pathomorphological methods. The proposed technique allowed us to rapidly (in two days after surgery) determine the level of infection with Mtb in the cells of the resected lungs of TB patients and, by the presence or absence of Mtb colonies, including those with cording morphology, the functional status of the TB agent at the time of surgery.

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