The promotion of eosinophil degranulation and adhesion to conjunctival epithelial cells by IgE-activated conjunctival mast cells.
BACKGROUND
Allergen-mediated mast cell activation is a key feature of ocular allergic diseases. Evidence of eosinophil-derived mediators in tears and conjunctival biopsy specimens has been associated with chronic ocular allergic inflammation.


OBJECTIVE
To examine the role of conjunctival mast cell mediators in eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation.


METHODS
Conjunctival cells were obtained by enzymatic digestion of cadaveric conjunctival tissues. Eosinophils were obtained from peripheral blood samples using negative magnetic bead selection. The effect of IgE-activated mast cell supernates on eosinophil degranulation and adherence to epithelial cells was compared with supernates obtained from mast cells pretreated with a degranulation inhibitor (olopatadine). Eosinophil adhesion was measured by eosinophil peroxidase assay, and eosinophil degranulation was measured by eosinophil-derived neurotoxin radioimmunoassay.


RESULTS
IgE-activated conjunctival mast cell supernates stimulated adhesion of eosinophils to epithelial cells (20.4% +/- 6.3% vs 3.1% +/- 1.0%; P = .048). Degranulation was not required for this process (no effect of olopatadine). IgE-activated mast cell supernates stimulated eosinophil-derived neurotoxin release (108.89 +/- 8.27 ng/10(6) cells vs 79.45 +/- 5.21 ng/10(6) cells for controls, P = .02), which was significantly inhibited by pretreatment of mast cells with a degranulation inhibitor (79.22 +/- 4.33 ng/10(6) cells vs 61.09 +/- 5.39 ng/10(6) cells for olopatadine pretreated and untreated, respectively, P = .02).


CONCLUSIONS
Mediators released from conjunctival mast cells promote eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. Degranulation inhibition studies suggest that different mast cell mediators are involved in regulation of these events.
Cook
Ellen B
EB
Department of Medicine, University of Wisconsin-Madison, School of Medicine, Madison, Wisconsin, USA.
Stahl
James L
JL
Sedgwick
Julie B
JB
Barney
Neal P
NP
Graziano
Frank M
FM
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000276:immunology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D015550:Cell Degranulation / Q000187:drug effects / Q000502:physiology; D003228:Conjunctiva / Q000166:cytology*; D003990:Dibenzoxepins / Q000494:pharmacology; D004804:Eosinophils / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008407:Mast Cells / Q000276:immunology*; D008875:Middle Aged; D000069605:Olopatadine Hydrochloride; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology
D003990:Dibenzoxepins; D000069605:Olopatadine Hydrochloride; D007073:Immunoglobulin E