In vitro Interaction between Human Basophils and Polymorphonuclear Granulocytes Effect of Airborne Particulate...

Area of Science:

• Immunology
• Environmental Health
• Cell Biology

Background:

• Airborne particulate matter (APM) is a complex mixture of particles found in the air.
• Exposure to APM is linked to respiratory and cardiovascular diseases.
• The specific mechanisms by which APM affects allergic inflammation are not fully understood.

Purpose of the Study:

• To investigate the effects of APM extracts on basophils and neutrophils.
• To determine if APM influences mediator release in allergic and non-allergic individuals.
• To explore the cellular and molecular responses to APM exposure in vitro.

Main Methods:

• Collection of APM using high-volume samplers.
• Preparation of aqueous extracts from APM, excluding allergens.
• In vitro incubation of enriched human basophils (HBC) and purified neutrophils (PMN) with APM extracts.
• Measurement of histamine release (HR) and other mediators (LTB4, LTC4, PGE2, IL-8).
• Morphological analysis using electron microscopy.

Main Results:

• APM extracts significantly potentiated anti-IgE-induced histamine release from HBC, with a greater effect in allergic individuals.
• Electron microscopy showed APM-induced degranulation of basophils, activation of platelets, and aggregation of neutrophils with basophils.
• APM exposure enhanced the release of LTB4, LTC4, PGE2, and IL-8 from neutrophils stimulated with zymosan.
• These findings suggest APM contains substances that 'prime' immune cells involved in allergic inflammation.

Conclusions:

• Substances adsorbed to APM interfere with mediator cells, exacerbating allergic inflammation.
• APM exposure can enhance allergy symptoms and prolong allergic inflammation.
• APM acts as a 'priming' agent on immune cells, increasing their responsiveness.