Augmentation of stimulated eosinophil degranulation by VLA-4 (CD49d)-mediated adhesion to fibronectin.
We examined the effect of VLA-4-mediated adhesion to purified fibronectin (FN) on the stimulated release of the granular protein, eosinophil peroxidase (EPO), in human peripheral blood eosinophils. In initial studies, optimal time-course and concentration-effect relationships were determined; eosinophil adhesion to FN-coated styrene plates was maximal in wells coated with 10 micrograms/ml FN after incubation in the wells for 60 min (17,097 +/- 3,670 adherent eosinophils/well versus 6,789 +/- 925 adherent eosinophils/well in control wells; P < 0.005). Treatment of eosinophils with 10(-8) to 10(-6) M formylmethionylleucyl-phenylalanine (FMLP) + 5 micrograms/ml cytochalasin B (CYTB) caused a concentration-dependent increase in EPO release, which was augmented by preincubation of eosinophils for 120 min in FN-coated (10 micrograms/ml) styrene wells versus eosinophils preincubated in control wells. At 10(-6) M FMLP+CYTB, initial adhesion to FN for 120 min caused an increase in the secretion of EPO from 367 +/- 26 to 485 +/- 25 ng/10(6) eosinophils (P = 0.0001). Treatment of eosinophils during incubation in FN-coated wells with the anti-VLA-4 monoclonal antibody HP2/1 attenuated stimulated EPO secretion caused by 10(-6) M FMLP+CYTB from 497 +/- 40 to 285 +/- 26 ng/10(6) eosinophils (P < 0.02). Similarly, treatment with HP2/1 caused a decrease in eosinophil adhesion to FN-coated styrene from 12,693 +/- 1,866 to 6,206 +/- 852 adherent cells/FN-coated well (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Neeley
S P
SP
Department of Medicine, University of Chicago, Illinois 60637.
Hamann
K J
KJ
Dowling
T L
TL
McAllister
K T
KT
White
S R
SR
Leff
A R
AR
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000502:physiology; D047209:Eosinophil Peroxidase; D004804:Eosinophils / Q000187:drug effects / Q000502:physiology*; D005353:Fibronectins / Q000494:pharmacology / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D007700:Kinetics; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D010544:Peroxidases / Q000032:analysis*; D016029:Receptors, Very Late Antigen / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D005353:Fibronectins; D016029:Receptors, Very Late Antigen; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D047209:Eosinophil Peroxidase; D010544:Peroxidases