Human alveolar T lymphocyte responses to Mycobacterium tuberculosis antigens: role for CD4+ and CD8+ cytotoxic T cells and relative resistance of alveolar …

JS Tan, DH Canaday, WH Boom, KN Balaji… - … (Baltimore, Md.: 1950 …, 1997 - journals.aai.org
JS Tan, DH Canaday, WH Boom, KN Balaji, SK Schwander, EA Rich
Journal of immunology (Baltimore, Md.: 1950), 1997journals.aai.org
T cell-mediated cytotoxicity against Mycobacterium tuberculosis (MTB)-infected
macrophages may be a major mechanism of specific host defense, but little is known about
such activities in the lung. Thus, the capacity of alveolar lymphocyte MTB-specific cell lines
(AL) and alveolar macrophages (AM) from tuberculin skin test-positive healthy subjects to
serve as CTL and target cells, respectively, in response to MTB (H37Ra) or purified protein
derivative (PPD) was investigated. Mycobacterial Ag-pulsed AM were targets of blood CTL …
Abstract
T cell-mediated cytotoxicity against Mycobacterium tuberculosis (MTB)-infected macrophages may be a major mechanism of specific host defense, but little is known about such activities in the lung. Thus, the capacity of alveolar lymphocyte MTB-specific cell lines (AL) and alveolar macrophages (AM) from tuberculin skin test-positive healthy subjects to serve as CTL and target cells, respectively, in response to MTB (H37Ra) or purified protein derivative (PPD) was investigated. Mycobacterial Ag-pulsed AM were targets of blood CTL activity at E:T ratios of > or = 30:1 (51Cr release assay), but were significantly more resistant to cytotoxicity than autologous blood monocytes. PPD- plus IL-2-expanded AL and blood lymphocytes were cytotoxic for autologous mycobacterium-stimulated monocytes at E:T ratios of > or = 10:1. The CTL activity of lymphocytes expanded with PPD was predominantly class II MHC restricted, whereas the CTL activity of lymphocytes expanded with PPD plus IL-2 was both class I and class II MHC restricted. Both CD4+ and CD8+ T cells were enriched in BL and AL expanded with PPD and IL-2, and both subsets had mycobacterium-specific CTL activity. Such novel cytotoxic responses by CD4+ and CD8+ T cells may be a major mechanism of defense against MTB at the site of disease activity.
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