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Gamma‐interferon inhibits Pneumocystis carinii attachment to lung cells by decreasing expression of lung cell‐surface integrins
Author(s) -
POTTRATZ S. T.,
WEIR A. L.
Publication year - 1997
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1046/j.1365-2362.1997.620612.x
Subject(s) - a549 cell , integrin , fibronectin , cell culture , western blot , pneumocystis carinii , microbiology and biotechnology , cytokine , interferon gamma , immunology , biology , cell , chemistry , biochemistry , pneumocystis jirovecii , genetics , human immunodeficiency virus (hiv) , gene
Pneumocystis carinii (PC) is a leading cause of pneumonia in immunocompromised patients. Previous work has shown that fibronectin (Fn) and Fn‐binding integrins mediate PC attachment to lung cells in vitro . Gamma‐interferon (γ‐IFN) is a major factor in host defence against PC infection. To determine the effect of γ‐IFN on PC attachment to lung cells, the alveolar epithelial cell line A549 was incubated with γ‐IFN (0–10 4 U mL −1 ) and attachment of 51 Cr‐labelled PC to the A549 cells was quantified. PC attachment was significantly decreased ( P < 0.01) by addition of γ‐IFN with no evidence of injury to either the PC or A549 cells. Effects of γ‐IFN on PC attachment were observed after 24 h and reached a maximum after 48 h of incubation. To investigate the mechanism of this decrease, we examined integrin expression on γ‐IFN‐treated A549 cells. A549 cell expression of the α 5 and β 1 integrin subunits was decreased, whereas expression of the α v subunit was unchanged. Northern blot analysis showed a similar decrease in mRNA for the α 5 and β 1 integrins. Therefore, γ‐IFN‐mediated inhibition of PC infection may, in part, result from inhibition of PC attachment to alveolar epithelial cells caused by γ‐IFN‐induced decreases in alveolar integrin expression.