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Eosinophils chemotactic factor (ECF). IV. Inhibitory activity in human peripheral leukocytes
International Archives of Allergy and Applied Immunology
|January 1, 1978
Summary
Human leukocytes release eosinophil chemotactic factor (ECF) and a leukocyte-derived inhibitor (LDI). This LDI binds ECF, modulating eosinophil activity without affecting neutrophils or bacterial factors.
Area of Science:
- Immunology
- Cell Biology
Background:
- Human peripheral polymorphonuclear leukocytes release eosinophil chemotactic factor (ECF).
- ECF release is triggered by phagocytosis, reverse anaphylaxis, or calcium ionophore A 23187.
- A leukocyte-derived ECF inhibitor (LDI) is released during later phases of ECF release.
Purpose of the Study:
- To characterize the leukocyte-derived ECF inhibitor (LDI).
- To investigate the mechanism of LDI action.
Main Methods:
- Chromatographic analysis of neutrophil (PMN) sonicates.
- Analysis of preparations containing lymphocytes, monocytes, and basophils (L/M/B).
- Heat stability and specificity assays for LDI activity.
Main Results:
- Two peaks of LDI activity were identified in PMN sonicates (>200,000 and ~80,000 daltons).
- Only the higher molecular weight peak (>200,000 daltons) was observed in L/M/B preparations.
- LDI is heat-stable, affects ECF but not eosinophils, and does not inactivate bacterial factors or deactivate neutrophils.
- Evidence suggests LDI acts by binding ECF, not enzymatic destruction.
Conclusions:
- Human leukocytes produce a preformed, heat-stable inhibitor (LDI) of eosinophil chemotactic factor (ECF).
- LDI appears to function by binding ECF, thereby modulating eosinophil migration.
- The molecular weight and presence of LDI may differ between leukocyte subsets.