Eosinophil chemotactic factor (ECF). III. Generation in human peripheral leukocytes.

Area of Science:

• Immunology
• Cell Biology

Background:

• Eosinophil chemotactic factor (ECF) plays a role in inflammatory responses.
• Previous studies suggested ECF might be preformed in mast cells.

Purpose of the Study:

• To investigate the generation and release mechanisms of ECF from human peripheral leukocytes.
• To determine if ECF is preformed within cells or actively synthesized.

Main Methods:

• Human peripheral leukocytes were stimulated using IgE-anti-IgE, calcium ionophore A 23187, and phagocytosis.
• ECF activity was measured in cell supernatants and sonicates.
• Chromatographic analysis was used to compare intracellular and released ECF.
• Metabolic inhibitors (2-deoxyglucose, colchicine) and DNA/protein synthesis inhibitors were employed.

Main Results:

• ECF is not detected in unstimulated leukocytes but is generated and released upon stimulation.
• ECF generation and release require calcium and intact cells.
• ECF is not preformed; intracellular and released ECF are chromatographically identical.
• Inhibition of DNA/protein synthesis did not affect ECF generation/release.
• 2-deoxyglucose suppressed supernatant ECF more than cell-bound ECF, while colchicine had the opposite effect.

Conclusions:

• ECF generation and release are active, distinct metabolic processes.
• ECF is not stored in a preformed state within leukocytes.
• These findings differentiate leukocyte ECF from mast cell ECF-A.