Human tonsillar germinal center T cells are a diverse and widely disseminated population

Abstract

Germinal center (GC) T cells are a poorly investigated population with a unique helper-inducer memory phenotype. Murine GC T cells have been demonstrated to be oligoclonal and antigen specific. The aim of this study was to investigate the diversity of human tonsillar GC T cells. Immunohistochemistry with a panel of different TCRVbeta family antibodies and sequencing of TCRgamma gene rearrangements obtained from individual microdissected GC demonstrated local diversity of human tonsillar GC T cells. No evidence of local clonal dominance or of a local migratory pathway from the T cell zone to adjacent GC was seen. Primers specific to the junctional region of the TCRgamma gene of individual GC T cell clones were designed, and used to trace the dissemination of the clones. One was found to be concentrated locally. Both clones studied were present in both of the patient's tonsils, suggesting widespread dissemination. In addition, no evidence of somatic hypermutation was found in the TCRgamma gene sequences, or in expressed TCRalpha and beta gene sequences obtained by reverse transcriptase-PCR from isolated tonsillar GC.

Peripheral T-cell lymphoma with involvement of the expanded mantle zone

“…Somatic hypermutation affects also the 5′-untranslated region of the BCL-6 gene, although the latter has only been shown for B-cells [19]. Whether or not somatic hypermutation occurs in human germinal center T-cells is controversial [5,9,23]. Bcl-6 expression is a recurrent finding in anaplastic large-cell lymphoma, in T-lymphoblastic lymphoma, and in a subset of PTCL as well as AILT.…”

Circulating T follicular helper cell and regulatory T cell frequencies are influenced by B cell depletion in patients with granulomatosis with polyangiitis

“…T follicular helper cells (TFHs), for example, are a T cell subset that normally resides in the germinal centres of secondary lymphoid tissues [17]. Clones of TFHs are known to disseminate, so that a single TFH clone can be detected in both tonsils [18]. Small populations of TFHs in blood are referred to as circulating TFH (cTFH) [19].…”

T‐Cell Receptor Repertoire in Human Germinal Centres

“…Thus, 40–60% of the T cells in GC express Vα11/Vβ3 TCR during a PCC response [12–14]. Recent data from human tonsils analyzed with a panel of different TCR Vβ family antibodies demonstrated a local diversity among GC T cells [15]. These experiments showed that although there are antigen specific T cells in the GC they are rather diverse.…”