Can persistent antigenic stimulation promote B-cell exhaustion and weaken antibody responses?

Persistent antigen exposure is most relevant in chronic infection and prolonged inflammatory states, where B cells can acquire an exhaustion-associated phenotype and provide less effective humoral protection. For an 83-year-old man, age-related reductions in B-cell functional capacity may compound these effects.

Clinical and functional evidence

• Chronic hepatitis B and HIV are associated with expansion of atypical or “exhaustion-associated” B-cell populations, commonly CD21-negative/CD27-negative and T-bet-positive, with reduced B-cell-receptor (BCR)-driven proliferation, differentiation into antibody-secreting cells, and antigen-specific antibody production.
• In chronic HBV, virus-specific B cells can remain present but generate weaker HBsAg-specific responses. In treated HIV, greater baseline frequencies of exhausted B cells have been associated with weaker vaccine antibody responses.
• Similar associations appear in vaccination studies: baseline CD21^low^ B cells and CD95 expression predicted inadequate SARS-CoV-2 vaccine responses in rituximab-treated patients and were inversely related to neutralizing-antibody levels. Higher age-associated B-cell frequencies before BNT162b2 vaccination were associated with fewer antigen-specific memory B cells and lower neutralizing titres.

Mechanistic interpretation

• Sustained BCR engagement, particularly alongside IFN-γ, CpG/TLR stimulation, CD40 signaling, and IL-21, can induce T-bet and FcRL5 expression and impair subsequent BCR signaling. Thus, persistent antigen is an important driver, but inflammatory and helper-cell signals shape the resulting state.
• Aging adds a biologically distinct vulnerability: reduced B-cell expression of activation-induced cytidine deaminase (AID) can impair class-switch recombination, potentially reducing antibody quality even apart from exhaustion-associated phenotypes.
• These cells are heterogeneous rather than uniformly or permanently nonfunctional; context influences FcRL5 signaling and residual capacity for activation or differentiation.

Bottom line

• Persistent antigenic stimulation can promote exhaustion-associated B-cell dysfunction, and these phenotypes are consistently linked with weaker antibody and vaccine responses. The relationship is biologically plausible and clinically relevant, especially when chronic inflammation, infection, immunosuppression, and advanced age coexist.