Origin and Function of Circulating Plasmablasts during Acute Viral Infections

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• B cells differentiate into antibody-producing plasma cells and memory cells post-infection.
• Memory B cells enable rapid responses upon re-exposure to antigens.
• Short-lived plasmablasts, including IgG and IgA, circulate transiently at high frequencies.

Purpose of the Study:

• To review the phenotype and origin of human plasmablasts during viral infections.
• To investigate the relationship between plasmablasts and memory B cell subsets.
• To assess plasmablasts as potential predictors of long-lived immunity.

Main Methods:

• Review of existing literature on human plasmablasts and viral infections.
• Analysis of immunoglobulin variable region mutations in plasmablasts.
• Comparison of plasmablast phenotypes with memory B cell subsets.

Main Results:

• Plasmablasts exhibit highly mutated and diverse immunoglobulin variable regions, suggesting memory B cell origin.
• The specific memory B cell subsets activating and their maturation status remain unclear.
• High frequencies of transient plasmablasts are observed in circulation following viral infections.

Conclusions:

• Plasmablasts likely arise from activated memory B cells, but the precise subset and maturation process require further elucidation.
• Understanding plasmablast dynamics is crucial for comprehending adaptive immunity to viral pathogens.
• Further research is needed to determine if plasmablasts can reliably predict long-lived immunity.