A screening method for antigen-specific IgE using mast cells based on intracellular calcium signaling

Area of Science:

• Immunology
• Cellular Biology
• Biochemistry

Background:

• Immunoglobulin E (IgE) plays a crucial role in allergic reactions.
• Accurate measurement of antigen-specific IgEs is vital for diagnosing and managing allergies.
• Current methods for IgE detection can be complex and time-consuming.

Purpose of the Study:

• To develop a simple and efficient screening method for measuring antigen-specific IgEs in serum.
• To utilize mast cells and their intracellular calcium signaling response for IgE detection.
• To establish a novel immunological assay based on Ca2+ signal transduction.

Main Methods:

• Mast cells (RBL2H3 cell line and primary BMMCs) were used as the detection system.
• Antigen-specific IgEs were captured by high-affinity Fc receptors (FcεRI) on mast cells.
• Intracellular calcium concentration ([Ca2+]i) increase, induced by antigen-IgE cross-linking, was monitored using Ca2+-fluorometry.
• DNP-specific IgE and OVA-specific IgE in rodent sera were quantified using DNP35-HSA and ovalbumin as model antigens.

Main Results:

• A linear correlation was observed between [Ca2+]i increase and IgE concentrations for DNP-specific IgE (25–5000 ng/mL) and OVA-specific IgE (5–50 ng/mL).
• Optimal antigen concentrations for detection were determined as 10 ng/mL for DNP35-HSA and 1 μg/mL for OVA.
• The Ca2+ signal transduction in mast cells proved to be a reliable indicator of antigen-specific IgE presence and quantity.

Conclusions:

• Monitoring the increase of intracellular calcium ([Ca2+]i) in mast cells allows for the determination of antigen-specific IgEs.
• This mast cell-based assay offers a new, efficient approach for screening antigen-specific IgEs and assessing IgE immunogenicity.
• The developed method provides a simplified and sensitive platform for allergy diagnostics and research.