Cryptococcal capsular glucuronoxylomannan reduces ischaemia-related neutrophil influx.
BACKGROUND
The capsular polysaccharide glucuronoxylomannan (GXM) of Cryptococcus neoformans interferes with the chemotaxis and transendothelial migration of neutrophils. Intravenous administration of purified GXM has been shown to reduce the influx of inflammatory cells in an animal model of bacterial infection. Here we show that isolated GXM can also interfere with neutrophil migration in a model of inflammation not related to infection. We assessed the effects of intravenous GXM on neutrophil infiltration in a rat model of myocardial ischaemia, where neutrophil infiltration has been shown to contribute to postischaemic reperfusion injury.


METHODS
Rats were subjected to coronary artery ligation followed by a 3-h reperfusion period. Myeloperoxidase-activity was measured in the ischaemic tissues as a marker of neutrophil infiltration.


RESULTS
Intravenous administration of GXM markedly reduced the influx of neutrophils in the ischaemic myocardium as measured by a 65% reduction of tissue MPO activity. This reduction of MPO activity was clearly correlated to the serum concentration of GXM. As complement activation by GXM was minimal at the doses applied in vivo, it is unlikely that generation of chemotactic C5a in the circulation by GXM caused the observed reduction in leucocyte migration.


CONCLUSIONS
Purified cryptococcal GXM has the ability to reduce neutrophil influx even outside the scope of infection.
Ellerbroek
P M
PM
University Medical Centre Utrecht, Utrecht, the Netherlands. p.ellerbroek@digd.azu.nl
Schoemaker
R G
RG
van Veghel
R
R
Hoepelman
A I M
AI
Coenjaerts
F E J
FE
D000818:Animals; D003182:Complement C5 / Q000276:immunology; D003331:Coronary Vessels; D003453:Cryptococcosis / Q000276:immunology; D003455:Cryptococcus neoformans; D008026:Ligation; D008297:Male; D017202:Myocardial Ischemia / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D011134:Polysaccharides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D003182:Complement C5; D011134:Polysaccharides; C027478:glucuronoxylomannan