Pulmonary surfactant and tuberculosis.
Mycobacterium tuberculosis comes in contact with pulmonary surfactant, alveolar macrophages and type II epithelial cells. Alveolar type II epithelial cells secrete pulmonary surfactant, a complex mixture of phospholipids and proteins lining the alveolar surface, while alveolar macrophages are involved in surfactant catabolism. Surfactant proteins SP-A and SP-D modulate phagocytosis of M. tuberculosis by alveolar macrophages. We have reported that mice with decreased surfactant catabolism resulting from GM-CSF deficiency are highly susceptible to acute aerosol infection with 100 cfu of M. tuberculosis. Here, we evaluated the lungs of WT, GM-CSF-deficient, and GM-CSF-corrected mice surviving six months after sub-acute aerosol infection of 5-10 cfu M. tuberculosis. We show that GM-CSF-deficient mice develop intra-bronchial and intra-alveolar tuberculosis lesions with numerous mycobacteria, inflammatory cells, and extracellular proteinaceous material containing surfactant protein B (SP-B). In contrast, WT and GM-CSF-corrected mice develop typical epithelioid granulomas containing lymphocytes, SP-B positive cells, and M. tuberculosis bacilli inside macrophages. Our findings support the concept that whole pulmonary surfactant is an important component of host mycobacterial infection in the distal lung.
Chroneos
Zissis C
ZC
University of Texas Health Science Center at Tyler, The Center of Biomedical Research, 11937 US Highway 271, Tyler, TX 75708-3154, USA. zissis.chroneos@uthct.edu
Midde
Krishna
K
Sever-Chroneos
Zvjezdana
Z
Jagannath
Chinnaswamy
C
D000818:Animals; D004847:Epithelial Cells / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000172:deficiency / Q000276:immunology*; D007150:Immunohistochemistry; D008168:Lung / Q000276:immunology / Q000473:pathology*; D016676:Macrophages, Alveolar / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000378:metabolism*; D037661:Pulmonary Surfactant-Associated Proteins / Q000276:immunology / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000276:immunology / Q000378:metabolism*; D014376:Tuberculosis / Q000276:immunology / Q000473:pathology*
D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D016178:Granulocyte-Macrophage Colony-Stimulating Factor