Durable SARS-CoV-2 B cell immunity after mild or severe disease

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• Waning SARS-CoV-2 antibody levels raise concerns about durable humoral immunity and reinfection risk.
• Memory B cells (MBC) are crucial for long-term immunity, even if antibody titers decrease.

Approach:

• Analyzed S protein receptor binding domain (S-RBD)-specific MBC in mild and severe COVID-19 patients using multi-dimensional flow cytometry.
• Assessed MBC phenotype and frequency at a median of 54 days post-symptom onset.

Key Points:

• S-RBD-specific class-switched MBC were detected in most participants, including those with low antibody levels.
• Resting MBC (rMBC) constituted the majority of S-RBD-specific MBC.
• FCRL5, a marker of functional memory, was highly expressed on S-RBD-specific rMBC.

Conclusions:

• Most SARS-CoV-2 infected individuals develop durable B cell-mediated immunity.
• The identified MBC resemble those induced by effective vaccination, indicating long-term protection potential.