Eosinophil degranulation. Monitoring by interference contrast microscopy

Area of Science:

• Immunology
• Cell Biology
• Microscopy

Background:

• Human eosinophils play a role in immune responses.
• Monitoring eosinophil degranulation is crucial for understanding allergic and inflammatory conditions.
• Existing methods for assessing eosinophil degranulation have limitations.

Purpose of the Study:

• To develop and validate a quantitative method for monitoring human eosinophil degranulation.
• To investigate the effects of various pharmacological agents on eosinophil degranulation.
• To elucidate the role of cyclic nucleotides in eosinophil degranulation.

Main Methods:

• Quantitative monitoring of human eosinophil degranulation using interference contrast microscopy.
• Stimulation of eosinophils with staphylococci and various agents (endotoxin-activated serum, ECF-A, phytohemagglutinin, concanavalin A, levamisole, compound 48/80).
• Assessment of the effects of pharmacological agents (colchicine, agents increasing cAMP or cGMP, disodium cromoglycate) on degranulation and phagocytosis.

Main Results:

• Degranulated eosinophils exhibited distinct morphological changes (larger size, ameboid shape) compared to non-degranulating cells.
• Agents increasing intracellular cyclic adenosine monophosphate (cAMP) inhibited degranulation, while those increasing cyclic guanosine monophosphate (cGMP) had no effect.
• Several agents, including compound 48/80, induced eosinophil degranulation, which was prevented by disodium cromoglycate.

Conclusions:

• Interference contrast microscopy provides a reliable method for quantifying eosinophil degranulation.
• Intracellular cAMP levels are critical in regulating eosinophil degranulation.
• Specific compounds can modulate eosinophil degranulation, offering potential therapeutic targets.