A whole blood-based functional assay to characterize immunoglobulin A effector functions

Area of Science:

• Immunology
• Molecular Biology

Background:

• Previous studies on immunoglobulin A (IgA) immune cell activation often used purified IgA or isolated cell types.
• IgA2 has been suggested to possess a more pro-inflammatory capacity than IgA1.

Purpose of the Study:

• To develop a rapid, whole blood assay for comparing the immune cell-activating potential of IgA1 and IgA2 subclasses under physiological conditions.
• To investigate the differential activation profiles of IgA1, IgA2m1, and IgA2m2 allotypes on various immune cell subsets.

Main Methods:

• Whole blood from healthy donors was stimulated with immobilized IgA1, IgA2m1, or IgA2m2.
• A 10-color flow cytometry panel was utilized to measure activation markers on major leukocyte subsets.

Main Results:

• IgA2m1 and IgA2m2 consistently induced stronger immune cell activation compared to IgA1 across multiple dimensions.
• Enhanced expression of CD54, CD11b, CD62L, CD66b, and CD69 was observed on monocytes and neutrophils stimulated with IgA2 allotypes.
• The study revealed donor-specific variations in immune responses.

Conclusions:

• IgA2 subclasses (IgA2m1 and IgA2m2) exhibit a more pronounced pro-inflammatory effect on immune cells than IgA1.
• The whole blood assay provides a valuable tool for studying IgA effector functions in mechanistic and translational research, considering donor variability.