Vaccination aims to elicit durable antigen-specific humoral immunity and cellular memory. However, individuals differ in the magnitude and persistence of vaccine-induced antibody responses. Antigen-specific antibodies originate in germinal centers (GCs), where T follicular helper (Tfh) cells provide essential help to B cells undergoing somatic hypermutation (SHM) and affinity maturation. The molecular and cellular features that connect GC dynamics to downstream antibody output in humans remain incompletely defined. This study used the pronounced variability in antibody concentration and durability after Hepatitis B virus (HBV) immunization to identify the cellular and transcriptional events associated with differential vaccine responsiveness.
Investigators longitudinally profiled 101 healthy adults receiving HBV immunization: 59 participants received de novo vaccination and 42 received booster vaccination. Participants were stratified into High responders (antibody titer >100 mIU/mL) and Low responders (antibody titer <100 mIU/mL) based on vaccine antigen-specific antibody concentrations and durability measurements reported in the cohort.
From this cohort, core needle biopsies (CNBx) of vaccine-draining lymph nodes were obtained from 10 participants (High Responder n=6, Low Responder n=4) between 10 and 21 days after the final vaccination. Single-cell RNA sequencing with paired antigen receptor sequencing was performed on these lymph node samples to interrogate both B and T cell compartments and link transcriptional programs to antigen receptor clonotypes.
Analysis of lymph node B cell receptor (BCR) repertoires revealed convergent, semi-public clonotypes shared across unrelated participants, consistent with common antigen-driven selection. These antigen-associated clonotypes exhibited elevated somatic hypermutation (SHM), supporting active germinal center-driven affinity maturation in the responding participants.
Single-cell transcriptomic profiling of GC-B cells uncovered pronounced functional differences between High and Low Responders. High Responders displayed robust activation across both dark zone (DZ) and light zone (LZ) GC compartments, with enrichment of transcriptional programs such as MYC and mTORC1 signaling. In contrast, Low Responders had a contracted LZ compartment and a transcriptionally stalled GC B cell response, indicating impaired progression through the GC reaction required for effective antibody maturation.
Changes in B cell responses corresponded with differences in the T cell compartment. High Responders had an expanded Tfh subset characterized by increased expression of CXCL13, ICOS, and GNG4, markers consistent with GC localization and helper function. Receptor–ligand interaction analysis indicated that these GNG4+ Tfh cells formed coordinated costimulatory networks predicted to license LZ GC-B cells, suggesting an effective T cell–B cell collaboration that supports robust GC activity and downstream antibody production.
Low Responders exhibited a divergent Tfh program: their GNG4+ Tfh cells displayed an aberrant inflammatory transcriptional signature. This inflammatory signaling correlated with reduced specificity of the BCL6 regulon activity, even though canonical Tfh genes remained expressed. The altered transcriptional network within this Tfh subset is associated with impaired capacity to drive productive GC B cell licensing and maturation.
These findings link variable HBV vaccine responsiveness to transcriptional network alterations in a defined Tfh subset, the GNG4+ Tfh population, and to downstream changes in GC-B cell activation and compartmentalization. The study provides a molecular framework for understanding why some individuals mount durable, high-titer antibody responses while others exhibit stalled GC reactions and poorer antibody outcomes after the same vaccine antigen.
The report is based on a longitudinal cohort of 101 adults with detailed lymph node single-cell profiling in a subset (n=10) sampled 10–21 days post-final vaccination. The source did not report additional methodological or cohort details beyond those summarized here. The authors conclude that transcriptional dysfunction within the GNG4+ Tfh subset underlies poor HBV vaccine responses and present a model linking altered Tfh–B cell interactions to ineffective germinal center output.