Defence mechanisms of human alveolar macrophages in tuberculosis

In human tuberculosis, the mechanisms leading to an effective immune defence in the lung are not understood. This work identified the Tumor Necrosis Factor and chemokines, which are secreted by alveolar macrophages as modulators of the immune response against mycobacteria. The following key results were obtained:1. The Tumor Necrosis Factor is secreted by alveolar macrophages and supports the growth of virulent mycobacteria.2. Infected alveolar macrophages attract lymphocytes, e.g. natural killer cells that express antibacterial effector molecules.3. After stimulation of Toll-like receptors, alveolar macrophages kill Mycobacterium tuberculosis.These results identify alveolar macrophages as key cells in the innate immune response to tuberculosis. The alveolar macrophages influence the growth of bacteria, are involved in the formation of granuloma and support the migration of antibacterial natural killer cells