A microfluidic strategy to capture antigen-specific high affinity B cells

Area of Science:

• Immunology
• Biophysics
• Microfluidics

Background:

• Current methods for assessing B cell responses and antibody affinity are often costly, time-consuming, and do not account for the influence of force on binding interactions.
• Recent research suggests that mechanical force can modulate B cell receptor (BCR)-antigen binding, impacting immune status assessment.

Purpose of the Study:

• To develop and validate a microfluidic strategy for assessing antigen-specific B cell receptor (BCR) binding affinity under physiologically relevant forces.
• To demonstrate the utility of this method in enriching for high-affinity B cells and correlating BCR-antigen interactions with antibody solution affinity.

Main Methods:

• A laminar flow microfluidic chamber was engineered with immobilized influenza A hemagglutinin antigen.
• Five hemagglutinin-specific hybridomas were analyzed for antigen-specific BCR binding affinity across a force range of 65 to 650 pN.
• The method assessed BCR binding under varying shear forces and measured bound lifetime.

Main Results:

• Increasing shear force and longer bound lifetimes effectively enriched for antigen-specific, high-affinity B cells.
• The measured affinity of membrane-bound BCRs in the microfluidic chamber showed strong correlation with the affinity of corresponding antibodies in solution.
• The microfluidic strategy demonstrated rapid assessment of BCR-antigen binding properties.

Conclusions:

• A microfluidic approach can rapidly and effectively assess BCR-antigen binding affinity and identify high-affinity B cells.
• This technology holds potential for assessing functional immune status from peripheral B cells.
• The method offers a cost-effective means for identifying B cells as sources for therapeutic antibody development.