Role of pulmonary alveolar macrophages in defense of the lung against Pseudomonas aeruginosa

Citation
Doy. Cheung et al., Role of pulmonary alveolar macrophages in defense of the lung against Pseudomonas aeruginosa, INFEC IMMUN, 68(8), 2000, pp. 4585-4592
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Immunology
Journal title
INFECTION AND IMMUNITY
ISSN journal
0019-9567 → ACNP
Volume
68
Issue
8
Year of publication
2000
Pages
4585 - 4592
Database
ISI
SICI code
0019-9567(200008)68:8<4585:ROPAMI>2.0.ZU;2-Q
Abstract
Alveolar macrophages (AM) provide one of the first lines of defense against microbial invasion in the lower airways, The role of AM in the clearance o f Pseudomonas aerrcginosa in mice after intrapulmonary challenge was evalua ted. AM were depleted by intranasal administration of liposome-encapsulated dichloromethylene diphosphonate, At 24 h following the instillation of lip osomes, a sublethal dose of P. aeruginosa was inoculated intranasally. Sple en, liver, and lung tissue was then evaluated for viable bacteria and for h istopathology, AM depletion of 78 to 88% did not affect the survival rate o f infected mice or clearance of P. aeruginosa from the spleen, liver, or lu ng, compared to the control group, but the mice's susceptibility to Klebsie lla pneumoniae was greatly enhanced. The recruitment of neutrophils to the lung was also not affected. Freshly explanted AM were not competent to phag ocytose unopsonized P. aeruginosa but were able to phagocytose zymosan part icles. Further studies were conducted to assess the in situ phagocytic acti vities of AM, Three hours after the intranasal instillation of P. aeruginos a or other particles, bronchoalveolar lavage was performed. AM phagocytosis of zymosan particles and latex beads exceeded that of P. aeruginosa, Neutr ophils were recruited to the lung in response to a high-dose bacterial chal lenge. These results suggest that AM do not play an important role in defen se of the lung against P. aeruginosa.