Frequency-potency analysis of IgG+ memory B cells delineates neutralizing antibody responses at single-cell...

Area of Science:

• Immunology
• Vaccinology
• Biotechnology

Background:

• Assessing B cell receptor (BCR) quantity and quality is crucial for understanding immune responses.
• Existing methods often focus on individual BCRs, limiting comprehensive analysis of B cell populations.

Purpose of the Study:

• To develop and validate a novel workflow for quantitative analysis of B cell frequency and BCR potency.
• To establish a frequency-potency algorithm for estimating antigen-specific memory B cell populations.
• To apply these methods to an HIV-1 fusion peptide (FP) immunization study for detailed B cell characterization.

Main Methods:

• Single-cell-derived antibody supernatant analysis (SCAN) workflow for efficient determination of quantitative BCR neutralizing activities.
• Development of a frequency-potency algorithm to estimate B cell frequencies based on neutralizing activity or binding affinity.
• Application of frequency-potency curves to analyze FP-specific immunoglobulin G (IgG)+ memory B cells in an HIV-1 immunization model.

Main Results:

• SCAN workflow efficiently quantifies BCR neutralizing activities at the single-cell level.
• Frequency-potency curves successfully elucidated the quantity and quality of FP-specific memory B cells across different conditions.
• BCR neutralizing activity was primarily correlated with binding affinity to the soluble envelope trimer.
• Dominant neutralizing antibody lineages were identified through frequency analysis.

Conclusions:

• The SCAN workflow and frequency-potency analysis offer a powerful approach for general B cell analysis and monoclonal antibody (mAb) discovery.
• These methods provide valuable insights into the characteristics of antigen-specific memory B cells.
• Findings offer specific rationales for optimizing HIV-1 FP-directed vaccine strategies.