摘要：SummaryT follicular helper (Tfh) cells provide critical help to B cells during the germinal center (GC) reaction to facilitate generation of protective humoral immunity. Accessing the human lymph node (LN) to study the commitment of CD4 T cells to GC Tfh cell differentiation duringin vivovaccine responses is difficult. We used ultrasound guided fine needle biopsy to monitor recall responses in axillary LNs to seasonal influenza vaccination in healthy volunteers. Specific expansion of GC cell subsets occurred exclusively within draining LNs five days postvaccination. Draining LN GC Tfh and precursor-Tfh cells express higher levels of CD38, ICOS, and Ki67, indicating they were significantly more activated, motile, and proliferating, compared to contralateral LN cells. These observations provide insight into the early expansion phase of the human Tfh lineage within LNs during a vaccine induced memory response and highlights early LN immune responses may not be reflected in the periphery.Graphical abstractDisplay OmittedHighlights•Early response to influenza vaccine is characterized by expansion of GC cell subsets•Specific expansion of CD38+ ICOS+ GC Tfh and Pre-Tfh occurs in draining LNs only•Activated GC Tfh and Pre-Tfh are also proliferating, expressing high levels of Ki67•Correlation between activated Pre-Tfh and activated c-Tfh suggests a potential originImmune response; Components of the immune system; Cell biology
