Enhanced responses to Mycobacterium tuberculosis antigens by human alveolar lymphocytes during active pulmonary tuberculosis.

Responses to mycobacterial and nonmycobacterial antigens were examined in bronchoalveolar cells (BAC) and peripheral blood mononuclear cells (PBMC) from patients with active pulmonary tuberculosis (n=16) and healthy subjects (n=23). DNA synthesis in BAC (but not PBMC) from tuberculosis patients was significantly increased in response to the mycobacterial antigens purified protein derivative (PPD), antigen 85, and mannose-capped lipoarabinomannan but not to nonmycobacterial antigens. The response to PPD was also increased in enriched alveolar lymphocytes from tuberculosis patients (P<.05). The frequency of interferon-gamma but not interleukin-4- or -10-producing cells by ELISAspot was increased in PPD-stimulated BAC from patients with tuberculosis (P<.05). Accessory function of alveolar macrophages for T lymphocyte responses was similar and suppressive activity was variably decreased in tuberculosis patients. Thus, there is compartmentalization of mycobacterial antigen-specific lymphocytes to the lungs during active tuberculosis that on challenge produce a Th1-type cytokine host response.