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Pneumocystis carinii major surface glycoprotein induces interleukin‐8 and monocyte chemoattractant protein‐1 release from a human alveolar epithelial cell line
Author(s) -
Thomas Benfield,
Bettina Lundgren,
James H. Shelhamer,
Jens Lundgren
Publication year - 1999
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.1365-2362.1999.00517.x
Subject(s) - a549 cell , chemokine , monocyte , interleukin 8 , proinflammatory cytokine , secretion , cytokine , cell culture , chemotaxis , stimulation , phagocyte , interleukin , microbiology and biotechnology , biology , chemistry , endocrinology , immunology , inflammation , biochemistry , immune system , receptor , genetics
Background The major surface glycoprotein (MSG) is an abundant, immunogenic glycoprotein located on the surface of Pneumocystis carinii . Little is known about the proinflammatory effects of MSG. Design We have investigated the effect of human MSG on the secretion of the chemokines interleukin 8 (IL‐8) and monocyte chemoattractant protein‐1 (MCP‐1) from an alveolar epithelial cell line (A549). Results Incubation of A549 cells with MSG in concentrations from 0.4 to 10 μg mL −1 for 24 h caused dose‐dependent increases in IL‐8 release (3.4‐fold above control, P < 0.01). Time course experiments showed increases in IL‐8 release at 4 h, 8 h and 24 h compared with control cultures (all P < 0.01). There was a minor (13%) dose‐ and time‐related increase in MCP‐1 release at 24 h ( P = 0.02). Co‐incubation of MSG with mannan or β‐glucan decreased IL‐8 release by 48% and 42% respectively, suggesting that MSG stimulates A549 cells in part through carbohydrate moieties. Dexamethasone significantly inhibited MSG‐induced IL‐8 release in concentrations of 10 −6 –10 −8 mol L −1 compared with control experiments ( P < 0.01). Ribonuclease protection assays for steady‐state IL‐8 mRNA showed that increases in response to MSG stimulation occurred by 4 h and persisted throughout 8 h of stimulation. Conclusion These findings suggest that MSG can alter alveolar epithelial cytokine release and may be capable of modulating the local inflammatory response in this manner.