Pneumocystis carinii major surface glycoprotein induces interleukin-8 and monocyte chemoattractant protein-I release from a human alveolar epithelialcell line
Tl. Benfield et al., Pneumocystis carinii major surface glycoprotein induces interleukin-8 and monocyte chemoattractant protein-I release from a human alveolar epithelialcell line, EUR J CL IN, 29(8), 1999, pp. 717-722
Citations number
35
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Background The major surface glycoprotein (MSG) is an abundant, immunogenic
glycoprotein located on the surface of Pneumocystis carinii. Little is kno
wn 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 (MC
F-1) from an alveolar epithelial cell line (A549).
Results Incubation of A549 cells with MSG in concentrations from 0.4 to 10
mu g mL(-1) for 24 h caused dose-dependent increases in IL-8 release (3.4-f
old above control, P < 0.01). Time course experiments showed increases in I
L-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 relea
se at 24 h (P = 0.02). Co-incubation of MSG with mannan or beta-glucan decr
eased IL-8 release by 48% and 42% respectively, suggesting that MSG stimula
tes A549 cells in part through carbohydrate moieties. Dexamethasone signifi
cantly inhibited MSG-induced IL-8 release in concentrations of 10(-6)-10(-8
) mol L-1 compared with control experiments (P < 0.01). Ribonuclease protec
tion assays for steady-state IL-8 mRNA showed that increases in response to
MSG stimulation occurred by 4h and persisted throughout 8 h of stimulation
.
Conclusion These findings suggest that MSG can alter alveolar epithelial cy
tokine release and may be capable of modulating the local inflammatory resp
onse in this manner.