Does Epstein-Barr virus establish lifelong latency in B cells and reactivate to renew viral antigen expression and immune activation?

EBV is a near-universal persistent herpesvirus infection. The central claim is substantially supported: EBV maintains a durable latent reservoir in B cells, and reactivation reliably restores lytic viral antigen expression; the extent to which this produces systemic immune activation in humans is less certain.

Latency and persistence

• EBV persists principally in rare, antigen-selected resting memory B cells. In healthy seropositive adults, infected circulating cells are typically CD27⁺/IgD⁻ memory B cells at roughly 1–50 per million B cells.
• These cells usually display latency 0—detectable noncoding EBER RNAs with no detectable latent proteins—or occasional restricted EBNA1/LMP2 expression. This minimizes immune visibility while retaining the viral genome.
• EBV persists as a chromatinized circular episome. EBNA1 supports oriP-dependent episomal replication and chromosome tethering during B-cell division, allowing inheritance by daughter cells and explaining host-level lifelong persistence.

Reactivation and antigen expression

• B-cell receptor stimulation and plasma-cell differentiation can induce the immediate-early lytic regulators BZLF1 and BRLF1. These initiate lytic transcription, viral DNA replication, and virion production.
• Thus, renewed—particularly lytic—viral antigen expression is an inherent feature of EBV reactivation. Lytic proteins are also recognized targets for EBV-specific CD8⁺ T cells.

Immune implications

• Reactivation can plausibly stimulate immunity through lytic antigens and viral DNA sensing: EBV DNA may activate TLR9 in plasmacytoid dendritic cells, promoting type-I interferon and downstream NK- and T-cell responses. Lytic-antigen-reactive T cells can produce IFN-γ, TNF, and IL-2.
• However, EBV also limits detection: BILF1 reduces MHC-I presentation and BGLF5 downregulates TLR9. Observational correlations between EBV transcripts and inflammatory cytokines do not establish that reactivation causes systemic inflammation.

Bottom line

• EBV lifelong B-cell latency and reactivation-associated lytic antigen expression are well established. Reactivation-induced immune activation is mechanistically credible, but human evidence does not yet prove a consistent causal role in systemic inflammation.