Effects of human lung fibroblasts on eosinophil degranulation.
BACKGROUND
Although eosinophils and fibroblasts are thought to contribute to the mechanisms of chronic asthmatic inflammation, the interaction between eosinophils and fibroblasts has not been thoroughly clarified. We examined eosinophil cationic protein (ECP) release from human eosinophils cultured in the presence of human lung fibroblast HFL-1.


METHODS
Eosinophils from healthy donors were cultured with or without C5a for 16 h in the presence of human fetal lung fibroblasts which had previously been incubated with or without TNF for 4 h. ECP in supernatants was measured by RIA.


RESULTS
ECP release was potentiated only when both eosinophils and fibroblasts were activated by C5a and TNF, respectively, while it was not significantly potentiated when either eosinophils or fibroblasts were activated. Paraformaldehyde fixation of fibroblasts had some suppressive effect on ECP enhancement, and mAb against GM-CSF partly inhibited ECP enhancement. Coculture of eosinophils and fibroblasts with stimulus treatment resulted in the enhancement of both eosinophil adhesion and ECP release. The potentiation of ECP release was partially inhibited by anti-ICAM-1 mAb, anti-CD18 mAb, and anti-CD29 mAb, which caused partial and comparable inhibition of the enhancement of eosinophil adhesion.


CONCLUSIONS
This study suggests that the activation of fibroblasts may have some role in the potentiation of ECP release from cocultured eosinophils, and that adhesion of eosinophils to fibroblasts may partly be involved in the mechanism of ECP potentiation.
Takafuji
S
S
Department of Internal Medicine, St Marianna University School of Medicine, Kanagawa, Japan.
Miyakuni
Y
Y
Nakagawa
T
T
Shoji
S
S
Murata
S
S
Yamamoto
K
K
Ito
K
K
D000911:Antibodies, Monoclonal / Q000276:immunology; D001798:Blood Proteins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D015550:Cell Degranulation; D002460:Cell Line; D002478:Cells, Cultured; D015936:Complement C5a / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D004306:Dose-Response Relationship, Immunologic; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology*; D005347:Fibroblasts / Q000187:drug effects / Q000276:immunology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D008168:Lung / Q000166:cytology / Q000276:immunology*; D012260:Ribonucleases; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D016207:Cytokines; D047091:Eosinophil Granule Proteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D015936:Complement C5a; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D012260:Ribonucleases