title: Pulmonary surfactant and tuberculosis.
abstract: 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.
authors.affiliation: 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
authors.forename: Zissis C
authors.initials: ZC
authors.lastname: Chroneos
authors.forename: Krishna
authors.initials: K
authors.lastname: Midde
authors.forename: Zvjezdana
authors.initials: Z
authors.lastname: Sever-Chroneos
authors.forename: Chinnaswamy
authors.initials: C
authors.lastname: Jagannath
mesh_terms: 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*
chemical_list: D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D016178:Granulocyte-Macrophage Colony-Stimulating Factor