Ex vivo expansion of alveolar macrophages with Mycobacterium tuberculosis from the resected lungs of patients with pulmonary tuberculosis

Abstract

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.