Distinguishing naive- from memory-derived human B cells during acute responses

Area of Science:

• Immunology
• Virology
• B-cell biology

Background:

• Investigating the role of B-cell memory in antibody titre decline after sequential influenza variant exposures.
• Examining whether naive and memory B cells maintain distinct phenotypes post-activation for ex vivo discrimination.

Purpose of the Study:

• To compare the differentiation capacity of naive and memory B cells.
• To determine if naive and memory B cells retain distinct phenotypes after activation.

Main Methods:

• Compared Toll-like receptor (TLR) agonists (R848, CpG) with IL-21 and sCD40L for human B-cell differentiation.
• Assessed post-activation phenotypes of naive and memory B cells using flow cytometry (FACS) and antibody-secreting cell (ASC) ELISPOT.
• Investigated B-cell differentiation in the presence of monocytes.

Main Results:

• R848, but not CpG, with monocytes, robustly induced plasmablast and ASC formation from both naive and memory B cells.
• Naive B cells showed equivalent ASC generation but less class-switch and altered CD27, CD38, CD20 expression compared to memory B cells.
• Increased IL-1β and IL-6 production observed with R848 and monocyte co-culture.

Conclusions:

• Naive and memory B cells robustly differentiate and generate ASCs when stimulated with R848, IL-21, sCD40L, and monocytes.
• Key phenotypic differences persist between activated naive and memory B cells.
• These differences may enable ex vivo discrimination and improved characterization of acute responses to influenza variants.