Tfh-like Cells Research Articles

CD4+ CD52lo T-cell expression contributes to the development of systemic lupus erythematosus

The cell-surface glycoprotein CD52 is widely expressed in lymphocytes. CD4+CD52hi T cells are functioning suppressor CD4+T cells. We investigated the role of the immune regulation of CD4+CD52 T cells in systemic lupus erythematosus (SLE). CD4+CD52lo T cells were increased in SLE patients, in positive correlation with SLEDAI, anti-ds-DNA antibody, and IgG concentration. Circulating follicular helper-like T cells (Tfh-like cells) were also increased in SLE, in positive correlation with CD4+CD52lo T cells. Chemokine receptor 8 (CCR8) expression in CD4+CD52lo T cells was increased. In vitro experiments using CD4 T cells of SLE patients showed that thymus and activation-regulated chemokine (TARC), a ligand of CCR8, contributed to the development of CD4+CD52hi T cells into CD4+CD52lo T cells. Our findings suggest that CD4+CD52lo T-cell upregulation is involved in the production of pathogens by autoantibodies, and TARC may contribute to the development of SLE through an aberrant induction of CD4+CD52lo T cells.

Vaccination establishes clonal relatives of germinal center T cells in the blood of humans.

Germinal center T follicular helper cells (GCTfh) in lymphatic tissue are critical for B cell differentiation and protective antibody induction, but whether GCTfh establish clonal derivatives as circulating memory T cells is less understood. Here, we used markers expressed on GCTfh, CXCR5, PD1, and ICOS, to identify potential circulating CXCR5+CD4+ Tfh-like cells (cTfh) in humans, and investigated their functional phenotypes, diversity, and ontogeny in paired donor blood and tonsils, and in blood after vaccination. Based on T cell receptor repertoire analysis, we found that PD-1-expressing cTfh and tonsillar GCTfh cells were clonally related. Furthermore, an activated, antigen-specific PD1+ICOS+ cTfh subset clonally expanded after booster immunization whose frequencies correlated with vaccine-specific serum IgG; these phenotypically resembled GCTfh, and were clonally related to a resting PD1+ICOS- CD4+ memory T cell subset. Thus, we postulate that vaccination establishes clonal relatives of GCTfh within the circulating memory CD4+CXCR5+PD1+ T cell pool that expand upon reencounter of their cognate antigen.

Single-cell profiling of lineage determining transcription factors in antigen-specific CD4+ T cells reveals unexpected complexity in recall responses during immune reconstitution.

Recent studies of protein and gene expression at the single-cell level have revealed that the memory T-cell compartment is more heterogeneous than previously acknowledged. Identifying different T helper subsets involved in memory responses at the single-cell level is thus necessary to understand the level of heterogeneity within this population. Antigen-specific CD4+ T cells were measured using the CD25/OX40 assay together with a qualitative multiplex single-cell RT-PCR assay. Transcription profiles and subset proportions within the antigen-specific CD4+ T-cell population were dissected. Cytomegalovirus (CMV)-specific CD4+ T-cell responses skewed toward a Th1 response, whereas Tetanus toxoid responses skewed toward a Th2 type response. Fluctuations in CD4+ T-cell subsets were observed within the HIV-Gag-specific response during ongoing antiretroviral therapy. Strong effector responses (Th1) were observed in early treatment, however with ongoing therapy this effector response significantly decreased in combination with an increase in Tregs and circulating Tfh-like BCL-6+ memory cells. The apparent increase in Tcm in peripheral blood after a several weeks of antiretroviral therapy may be due to Tfh-like cell egress from germinal centers into the periphery.

Characterization of pathways involved in the suppression of T follicular helper cells in newborns

Abstract The immature immune system of newborns renders poor vaccine response. However, mechanisms of limited T follicular helper (Tfh)-mediated antibody production in newborns are largely unknown. We found significantly more expression of the Tfh inhibitory genes associated with regulatory T cell (Treg) cells and IL-2 signaling in immunized newborn mice CD4+CXCR5+PD-1+Tfh cells than in adult mice. The IL-2-STAT5 signaling in CD4+CXCR5+PD-1+Foxp3+T follicular regulatory cells (Tfr) was hyperactive in newborns as compared to adults. Also, in newborns IL-6-STAT3 signaling was lower in Tfh cells but higher in Tfr cells compared to adult mice. Immunization did not elicit IL-21 expressing Tfh cells but when provided sufficient IL-21, in vitro cultured newborn T cells differentiated into Tfh-like cells. These data indicate that in newborns, dendritic cell-derived IL-6 signaling preferentially induces Treg cells to differentiate into Tfr cells, which in turn suppresses Tfh generation. Supporting this hypothesis, co-injection of newborn mice with conjugate type 14 pneumococcal polysaccharide vaccine together with IL-21 or anti-CD25 blocking antibody reduced Tfr/Tfh ratio and enhanced Tfh formation. While IL-21 elicited both IgG and IgA antibodies against vaccine, anti-CD25 antibody only improved IgA production, due in part to the elevated APRIL and TGF-β expression in T cells and fibroblast reticular cells. Since IL-21 acts both on T cells and B cells, improved IgG response in IL-21 injected mice is likely due to its direct effect on B cells. These findings highlight the differences in the programming of IL-2 and IL-6 signaling in newborn and adult Tfh cells. These differences may be exploited in devising improved vaccines for infants.

Early differences in TCR signal strength modulate effector and memory differentiation of CD4+ T cells responding to viral infection.

Abstract Heterogeneity in TCR-dependent activation signals influences both effector differentiation and memory formation of CD4+ T cells. Our previous studies found that the formation of CD4+ memory T cells specific for lymphocytic choriomeningitis virus (LCMV) was associated with the selection of TCRs with sustained antigen binding properties. The goal of the current study was to define early TCR-dependent activation events that promote memory differentiation. We found that early in vitro and in vivo activation of distinct T cell clones specific for the same LCMV antigen demonstrated highly variable NFAT transcriptional activity and expression of early activation markers such as CD25. Clones with enhanced memory potential had reduced NFAT activity in vitro and rapid down-regulation of CD25 in vivo. We further observed decreased CD3ζ and Zap-70 phosphorylation, as well as a decrease in NFAT-dependent gene transcription, in virus-specific CD4+ T cells that displayed decreased CD25 surface expression early after LCMV infection. Adoptive transfer of CD25hi or CD25lo effector T cells (d3 or d5 post-infection) into infection-matched hosts revealed that the vast majority of both Th1-like and Tfh-like memory cells derived from CD25lo effector cells. RNASeq analysis further confirmed enrichment of genes associated with enhanced memory development within CD25lo effector cells, including Tcf-1 and OCA-B, but decreased expression of genes associated with enhanced effector activity. We conclude that differences in TCR signal strength account for clonal differences in CD4+ memory T cell differentiation, with weaker early TCR signals permitting long-term memory formation without terminal effector differentiation.

Heterogeneity of Phenotype and Function Reflects the Multistage Development of T Follicular Helper Cells.

T follicular helper cells (Tfh) provide crucial signals for germinal center (GC) formation, but Tfh populations are heterogeneous. While PD1hi Tfh are important in the GC response, the function of the PD1lo Tfh-like subset is unknown. We show that these cells, like the PD1hi GC–Tfh, depend upon B cells; however, their entry to follicles is independent of CXCR5 or cognate interactions with B cells. The differentiation into PD1hi Tfh is dependent on MHC class II interactions with B cells and requires CXCR5. Our data suggest a Tfh differentiation pathway that is initially B cell-independent, then dependent on non-cognate B cell interactions, and finally following cognate interaction with B cells and CXCR5-ligands allows the formation of GC–Tfh. The PD1lo Tfh-like cells make early cytokine responses and may represent precursors of CD4 memory cells.

Expansion of circulating follicular T helper cells associates with disease severity in childhood atopic dermatitis

Follicular helper T (TFH) cells play crucial role in B-cell differentiation and antibody production. Although, atopic dermatitis (AD) is often associated with increased serum IgE levels, B-cell mediated responses have not been studied thoroughly. The aim of our study was to investigate the proportion of TFH-like cells in the disease. Twelve children and 17 adults with AD as well as 14 healthy controls were enrolled in the study. The frequency of CD4+CXCR5+ICOS+PD-1+ TFH-like cells and their IL-21 cytokine production were determined by flow cytometry. Immunohistochemical analysis was performed on skin biopsy specimens from AD patients for the detection of TFH markers. The percentages and absolute numbers of circulating TFH-like cells were significantly increased in children with AD compared to adult patients and healthy controls. IL-21 cytokine production of TFH-like cells was also elevated and showed a strong positive correlation with paediatric patients’ SCORAD index. The expression of TFH-specific markers showed only a non-specific scattered pattern in skin biopsy specimens. This is the first study to demonstrate that TFH-like cells expanded in the peripheral blood of children with AD compared to adults. These results reinforce the importance of further investigations on TFH-like cells in different phenotypes and endotypes of AD.

Increased circulating CXCR5+ CD4+ T follicular helper-like cells in oral lichen planus.

CD4+ T-helper cell is crucial for the inflammatory autoimmune condition of oral lichen planus (OLP). Recently, the pathogenetic functions of T follicular helper (Tfh) cells, a subtype of CD4+ T-helper cells, have been revealed in autoimmune diseases for their pivotal regulation on humoral immunity. To explore the potential pathophysiological role of Tfh cells in OLP, the expression of circulating Tfh-like cells and its correlations with IL-21 and B cells were investigated. The frequencies of CXCR5+ CD4+ Tfh-like cells and CD19+ B cells were analyzed in peripheral blood of patients with OLP and controls by flow cytometry, respectively. Besides, the serum IL-21 concentration was measured using ELISA technology. Furthermore, the correlations of CXCR5+ CD4+ Tfh-like cells with CD19+ B cells and serum IL-21 expression levels were evaluated. This study showed significant increased circulating Tfh-like cells (P < 0.05) and B cells (P < 0.0001), as well as decreased serum IL-21 expression (P < 0.001) in OLP. Besides, the frequency of Tfh-like cells exhibited negative correlation with B cells in OLP (r = -0.435, P < 0.05). In particular, the proportion of CXCR5+ CD4+ Tfh-like cells in peripheral blood mononuclear cells of erosive OLP was higher than non-erosive OLP and controls (P = 0.012 and 0.021, respectively). Increased circulating Tfh-like cells may be involved in the pathogenesis of OLP through abnormal modulation on B-cell proliferation and IL-21 production, and associated with different clinical forms of OLP.

Circulating CXCR5+CXCR3+PD-1lo Tfh-like cells in HIV-1 controllers with neutralizing antibody breadth.

HIV-1-specific broadly neutralizing antibodies (bnAbs) typically develop in individuals with continuous high-level viral replication and increased immune activation, conditions that cannot be reproduced during prophylactic immunization. Understanding mechanisms supporting bnAb development in the absence of high-level viremia may be important for designing bnAb-inducing immunogens. Here, we show that the breadth of neutralizing antibody responses in HIV-1 controllers was associated with a relative enrichment of circulating CXCR5+CXCR3+PD-1lo CD4+ T cells. These CXCR3+PD-1lo Tfh-like cells were preferentially induced in vitro by functionally superior dendritic cells from controller neutralizers, and able to secrete IL-21 and support B cells. In addition, these CXCR3+PD-1lo Tfh-like cells contained higher proportions of stem cell-like memory T cells, and upon antigenic stimulation differentiated into PD-1hi Tfh-like cells in a Notch-dependent manner. Together, these data suggest that CXCR5+CXCR3+PD-1lo cells represent a dendritic cell-primed precursor cell population for PD-1hi Tfh-like cells that may contribute to the generation of bnAbs in the absence of high-level viremia.

Chronic HIV-1 Infection Impairs Superantigen-Induced Activation of Peripheral CD4+CXCR5+PD-1+ Cells, With Relative Preservation of Recall Antigen-Specific Responses.

Peripheral CD4+CXCR5+PD-1+ T cells are a putative circulating counterpart to germinal center T follicular helper (TFH) cells. They show both phenotypic and functional similarities to TFH cells, which provide necessary help for the differentiation of B cells to antibody-secreting plasmablasts. In this study, we evaluated the frequency, phenotypes, and responses of peripheral TFH-like (pTFH) cells to superantigen and recall antigen stimulation in 10 healthy and 34 chronically infected treatment-naive HIV-1+ individuals. There was no difference in the frequency of pTFH cells between HIV+ and HIV- individuals. Surface expression of ICOS, but not CD40L, was higher on pTFH cells at baseline in HIV+ individuals. Compared with HIV- individuals, pTFH cells from HIV+ individuals had decreased maximal expression of ICOS and CD40L in response to in vitro superantigen stimulation. This decreased response did not correlate with viral control, CD4 T-cell count, duration of infection, or the degree of neutralizing antibody breadth. Despite a decreased maximal response, pTFH responses to HIV Gag and tetanus toxoid recall antigens were preserved.

Polarization of Tissue-Resident TFH-Like Cells in Human Hepatoma Bridges Innate Monocyte Inflammation and M2b Macrophage Polarization.

We identified a novel protumorigenic IL21+ TFH-like cell subset with a CXCR5-PD-1- BTLA-CD69hi tissue-resident phenotype in hepatoma. TLR4-mediated monocyte inflammation and subsequent T-cell STAT1 and STAT3 activation are critical for TFH-like cell induction. TFH-like cells operate via IL21-IFNγ pathways to induce plasma cells and create conditions for M2b macrophage polarization. Cancer Discov; 6(10); 1182-95. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1069.

Imbalance of circulating CD4+CXCR5+FOXP3+ Tfr-like cells and CD4+CXCR5+FOXP3− Tfh-like cells in myasthenia gravis

Follicular regulatory T (Tfr) cells are defined as a specialized subset of regulatory T cells (Tregs) that act to control the overactivation of follicular helper T (Tfh) cells and B cells in germinal centers. Accumulating evidence has demonstrated that the dysregulation of either Tfr cells or Tfh cells results in abnormal germinal center responses that contribute to the pathogenesis of autoimmune diseases. However, the role that Tfr cells and Tfh cells play in myasthenia gravis (MG) remains unclear. This study revealed a significantly decreased frequency of CD4+CXCR5+FOXP3+ Tfr-like cells and an increased frequency of CD4+CXCR5+FOXP3− Tfh-like cells in the peripheral blood of MG patients compared with healthy controls. Moreover, the Tfr-like/Tfh-like ratio was inversely correlated with the clinical severity of the MG patients. Interestingly, glucocorticoid (GC) treatment can restore the imbalance of circulating Tfr-like/Tfh-like cells, and this restoration is accompanied by reduced clinical symptoms. These results suggested, for the first time, that an imbalance of circulating Tfr-like and Tfh-like cells may be involved in the immunopathogenesis of MG and may provide novel insight for the development of MG therapies.

Dysregulated CD8 T cells resemble Tfh-like cells and promote B cell activation during autoimmunity.

Abstract T follicular helper (Tfh) cells provide essential help for the development of antigen specific antibodies during normal and autoreactive immune responses. IL-2-deficient (KO) mice suffer from excessive lymphoproliferation and spontaneous, systemic autoimmune disease. Depletion of CD4 T cells in IL-2-KO mice eliminates the generation of RBC-specific antibodies, augmenting survival. Surprisingly, depletion of CD8 T cells in IL-2-KO mice also reduces disease and prolongs survival. Several groups have demonstrated a protective role for CD8 T cells in inflammation and autoimmunity, while others have suggested a pathogenic role. However the mechanisms of CD8 T cell influence on autoimmune disease are largely unknown. We have identified a new CD8 Tfh-like population in an autoimmune setting. RNA-sequencing of day 12 IL-2-KO CD8 T cells revealed an increase in the expression of genes associated with the CD4 Tfh lineage (Bcl-6, CXCR5, PD-1, ICOS and IL-21) compared with wild-type CD8 T cells. Flow cytometry confirmed the presence of expanded CD4 Tfh and CD8 Tfh-like cells, and the production of IL-21 in IL-2-KO mice. Germinal center tissue staining revealed localization of both CD4 and CD8 T cells to the germinal center during autoimmunity. In vitro, IL-2-KO CD8 T cells induced proliferation and activation of B cells. Our results indicate that autoreactive CD8 T cells contribute to the autoimmune disease in part through dysregulated follicular-like differentiation and function. NIH funding R00HL090706.

Differential regulation of TH1, TFH, and TCM gene programs by cytokine-mediated events

Abstract During the course of an immune response, multiple effector T helper cell types emerge to combat the initial infection, with subsequent emergence of long-term CD4+ T memory cells to ensure that a second exposure to the same pathogen will not cause disease. CD4+ T helper cell populations that are critical for this process include T helper 1 (TH1) and T follicular Helper (TFH) effector cells and long-lasting central memory T (TCM) cells. Previous work has demonstrated a level of flexibility between effector TH1 and TFH-like cell populations, with the respective gene programs regulated by alterations in interleukin 2 (IL-2) signaling. Here, we demonstrate that in response to decreased IL-2 signaling, effector TH1 cells are capable of initiating the expression of both TFH and TCM-like gene programs, including cell surface expression of IL-6Ra and IL-7R. Importantly, exposure of these cells to either IL-6 or IL-7 augments or inhibits the TFH gene program, respectively, suggesting a potential mechanism whereby cytokine availability may influence TFH or TCM cell function. Consistent with this model, we have identified a novel population of IL-6Ra+IL-7R+ cells that emerge at late time points post-infection in an in vivo mouse model of influenza infection. Further research into the temporal and spatial expression of IL-2, IL-6, and IL-7 in the modulation of these cells represents an exciting avenue of research with wide-ranging therapeutic implications.

CXCL13 is a plasma biomarker of germinal center activity

Significantly higher levels of plasma CXCL13 [chemokine (C-X-C motif) ligand 13] were associated with the generation of broadly neutralizing antibodies (bnAbs) against HIV in a large longitudinal cohort of HIV-infected individuals. Germinal centers (GCs) perform the remarkable task of optimizing B-cell Ab responses. GCs are required for almost all B-cell receptor affinity maturation and will be a critical parameter to monitor if HIV bnAbs are to be induced by vaccination. However, lymphoid tissue is rarely available from immunized humans, making the monitoring of GC activity by direct assessment of GC B cells and germinal center CD4(+) T follicular helper (GC Tfh) cells problematic. The CXCL13-CXCR5 [chemokine (C-X-C motif) receptor 5] chemokine axis plays a central role in organizing both B-cell follicles and GCs. Because GC Tfh cells can produce CXCL13, we explored the potential use of CXCL13 as a blood biomarker to indicate GC activity. In a series of studies, we found that plasma CXCL13 levels correlated with GC activity in draining lymph nodes of immunized mice, immunized macaques, and HIV-infected humans. Furthermore, plasma CXCL13 levels in immunized humans correlated with the magnitude of Ab responses and the frequency of ICOS(+) (inducible T-cell costimulator) Tfh-like cells in blood. Together, these findings support the potential use of CXCL13 as a plasma biomarker of GC activity in human vaccine trials and other clinical settings.

Flow Cytometric Characterization of 129 Cases of Peripheral T Cell Lymphoma Not Otherwise Specified (PTCL NOS) and Angioimmunoblastic T Cell Lymphoma (AITL)

Background: Peripheral T cell lymphoma not otherwise specified (PTCL NOS) and angioimmunoblastic T cell lymphoma (AITL) together comprise approximately half of all peripheral T cell lymphomas. Malignant T cells in AITL and in a subset of PTCL-NOS exhibit a phenotype mimicking that of normal T-follicular helper (TFH) cells. Immunohistochemical (IHC) studies performed on paraffin-embedded tissues are a mainstay of diagnostic histopathology, but can be difficult to interpret when the malignant T cells show limited cytological atypia and when there are abundant infiltrating reactive T cells. Flow cytometry represents an alternate means to define the cellular immunophenotype, but requires access to single cell suspensions of viable tumor cells. Flow cytometry has certain additional benefits over IHC including highly quantitative measurement of multiple antigens simultaneously and statistical power afforded by analyzing tens of thousands of individual cells. We report here immunophenotypic characterization of a large cohort of cases of PTCL NOS and AITL using a 12-color flow cytometry assay and correlation of immunophenotypic features with clinical outcomes.Methods: Cases of PTCL-NOS and AITL spanning a 24 year period (1990-2014) for which viably frozen cell suspensions from diagnostic lymph node biopsies were available were identified within the British Columbia Cancer Agency (BCCA) lymphoma database. Cryopreserved cell suspensions were thawed and stained with a 12-color panel including 11fluorochrome-conjugated antibodies against lineage (CD45, CD19, CD3, CD4, CD8), pan-T cell (CD2, CD5, CD7), and TFH cell (CD10, CD279, CXCR5) markers, plus DAPI for gating of live cells. Flow cytometric data was acquired on a Becton Dickinson FACSAria3 instrument as part of a sorting experiment to isolate tumor cell subpopulations. Data was analyzed by conventional gating and bivariate plot display using FlowJo software and correlated with clinical outcome data.Results: 74 cases of PTCL-NOS and 55 cases of AITL were analyzed. The median age at diagnosis was 57 years (y) for PTCL NOS (male:female 1.6) and 75 y for AITL (male:female 1.0). The median follow up for living patients was 5.15 y. The median specimen viability was 36.5% (range 0.8-89.3%) and median specimen tumour content was 64.3% of viable events (range 0.98-91.8%). Aberrant T cell immunophenotypes were identified in 50 of 74 cases (68%) of PTCL NOS and 36 of 55 cases (65%) of AITL. Five specimens had more than one identifiable immunophenotypically aberrant T cell population.For the 50 PTCL NOS cases with an aberrant immunophenotype, 31 (62%) demonstrated loss of CD3 and 42 (84%) demonstrated loss of CD7. About half of cases were CD4+CD8- (27, or 54%) including 11 (22%) that exhibited a TFH-like phenotype (positive for at least 2 of the 3 assayed TFH markers), while the remaining were CD4-CD8- (23, or 46%). TFH-like cells were also identified in 11 of 24 (46%) cases lacking an aberrant T cell immunophenotype.For the 36 AITL cases with an aberrant immunophenotype, 21 (58%) demonstrated loss of CD3 and 29 (80%) demonstrated loss of CD7. The majority of cases were CD4+ (30, or 83%) including 21 (58%) that exhibited a TFH-like phenotype, while the remaining were either CD8+ (4, or 11%) or CD4-CD8- (2, or 6%). TFH-like cells were also identified in 7 of 19 (37%) cases lacking an aberrant T cell immunophenotype.Similar to other patient cohorts, the 5 y PFS and 5 y OS was 21% and 40%, respectively, for PTCL NOS and 17% and 28%, respectively, for AITL. The presence of an aberrant phenotype, CD3 status, and CD4/CD8 status were not associated with prognosis in either PTCL subtype. A preliminary analysis suggests loss of CD7 expression in PTCL NOS is associated with an inferior outcome. Analysis of archival material and exploration in a validation cohort is ongoing.Discussion: An aberrant population of varying abundance was detected in >65% of specimens for PTCL NOS and AITL. The aberrant immunophenotype in PTCL NOS was evenly split between CD4+CD8- and CD4-CD8- cases. Interestingly, nearly half of CD4+ cases showed evidence of TFH-like differentiation, possibly corresponding to the TFH-like variant of PTCL NOS. The aberrant immunophenotype in AITL was typically CD4+ and often with co-expression of TFH-associated markers. Loss of CD7 and CD3 were the most common abnormalities. Loss of CD7 may demonstrate a poor-risk group of patients with inferior outcomes in PTCL NOS. DisclosuresSavage:Seattle Genetics: Honoraria, Speakers Bureau; BMS: Honoraria; Infinity: Honoraria; Roche: Other: Institutional research funding.

Role of Bcl‐3 in the Development of Follicular Helper T Cells and in the Pathogenesis of Rheumatoid Arthritis

We have previously shown that expression of the Bcl-3 gene, a member of the IκB family, is down-regulated in CD4+ T cells from patients with rheumatoid arthritis (RA) following tocilizumab therapy. The objective of this study was to examine the role of Bcl-3 in the pathogenesis of RA. DNA microarray analysis was used to compare the signal intensity of Bcl-3 in CD4+ T cells from untreated RA patients and healthy controls. We examined the roles of interleukin-6 (IL-6)/STAT-3 signaling in the induction of Bcl-3. In addition, we analyzed the gene expression profiles of Bcl-3-transduced CD4+ T cells by RNA sequencing. The effects of enforced expression as well as gene silencing of Bcl-3 on the development of follicular helper T (Tfh) cells were evaluated. Finally, we examined correlations between the signal intensities of Bcl-3 and Tfh cell-related genes in CD4+ T cells from untreated RA patients. Bcl-3 levels were significantly higher in RA patients than in healthy controls. IL-6 induced Bcl-3 expression in CD4+ T cells in a STAT-3-dependent manner. Transcriptome analysis revealed that the expression of Bcl-6, a master regulator of Tfh cell differentiation, was significantly up-regulated by the enforced Bcl-3 expression. The enforced Bcl-3 expression increased, but Bcl-3 silencing decreased, the numbers of IL-21-producing Tfh-like cells. Bcl-3 levels in CD4+ T cells from RA patients correlated positively with the levels of Tfh cell-related genes CXCR5, inducible costimulator, and achaete-scute homolog 2. Bcl-3 is involved in the development of Tfh cells and the pathogenesis of RA, presumably by inducing IL-21 production.

Circulating CXCR5⁺CD4⁺ T Follicular-Like Helper Cell and Memory B Cell Responses to Human Papillomavirus Vaccines.

Through the interaction of T follicular helper (Tfh) cells and B cells, efficacious vaccines can generate high-affinity, pathogen-neutralizing antibodies, and memory B cells. Using CXCR5, CXCR3, CCR6, CCR7, PD1, and ICOS as markers, Tfh-like cells can be identified in the circulation and be classified into three functionally distinct subsets that are PD1+ICOS+, PD1+ ICOS-, or PD1-ICOS-. We used these markers to identify different subsets of CXCR5+CD4+ Tfh-like cells in response to highly immunogenic and efficacious vaccines for human papillomaviruses (HPV): Cervarix and Gardasil. In this small study, we used PBMC samples from 11 Gardasil recipients, and 8 Cervarix recipients from the Vaccine Research Center 902 Study to examine the induction of circulating Tfh-like cells and IgD-CD38HiCD27+ memory B cells by flow cytometry. PD1+ICOS+ CXCR3+CCR6-CXCR5+CD4+ (Tfh1-like) cells were induced and peaked on Day (D) 7 post-first vaccination, but not as much on D7 post-third vaccination. We also observed a trend toward increase in PD1+ICOS+ CXCR3-CCR6-CXCR5+CD4+ (Tfh2-like) cells for both vaccines, and PD1+ICOS+ CXCR3-CCR6+CXCR5+CD4+ (Tfh17-like) subset was induced by Cervarix post-first vaccination. There were also minimal changes in the other cellular subsets. In addition, Cervarix recipients had more memory B cells post-first vaccination than did Gardasil recipients at D14 and D30. We found frequencies of memory B cells at D30 correlated with anti-HPV16 and 18 antibody titers from D30, and the induction levels of memory B cells at D30 and PD1+ICOS+Tfh1-like cells at D7 post-first vaccination correlated for Cervarix. Our study showed that induction of circulating CXCR5+CD4+ Tfh-like subsets can be detected following immunization with HPV vaccines, and potentially be useful as a marker of immunogenicity of vaccines. However, further investigations should be extended to different cohorts with larger sample size to better understand the functions of these T cells, as well as their relationship with B cells and antibodies.

The influence of paediatric HIV infection on circulating B cell subsets and CXCR5(+) T helper cells.

SummaryAntiretroviral therapy (ART) only partially restores HIV‐induced alterations in lymphocyte populations. We assessed B and T cell phenotypes in a cohort of children from a single centre in the United Kingdom with perinatally acquired HIV compared to healthy controls. The majority of HIV infected children (44 of 56) were on fully suppressive combination ART. Children with perinatally acquired HIV had significantly lower memory B and CD4+CD45RO+CXCR5+ [follicular T helper cell (Tfh)‐like] T cell percentages. Detectable viraemia was associated with higher CD21– (activated and exhausted/tissue‐like memory) B cells. A greater proportion of life spent on suppressive ART was associated with higher memory B cell percentages. These results suggest that early and sustained suppressive ART may preserve B and T cell phenotypes in perinatally acquired HIV and limit deficits in humoral immunity. A lower proportion of circulating Tfh‐like cells in HIV infected children appears to be independent of HIV treatment history and ongoing HIV viraemia and warrants further investigation.

Induction of tissue-resident TFH-like cells in human cancer links monocyte activation to M2b macrophage polarization (TUM10P.1021)

Abstract The existence, regulation, and functions of IL-21+ immune cells are poorly defined in human cancers. Here we identified a subset of protumorigenic IL-21+ TFH-like cells in human hepatocellular carcinoma. These cells were the major source of IL-21 in tumors and represented about 10% of the CD4+ T cell population at levels comparable to amounts of TFH cells present in lymph nodes. However, the TFH-like cells displayed a unique CXCR5−PD-1−BTLA−CD69high tissue-resident phenotype with substantial IFN-γ production, which differed from the phenotype of TFH cells. TLR4-elicited innate monocyte inflammation was essential for IL-21+ TFH-like cell induction in tumors, and activation of STAT1 and STAT3 was critical for TFH-like cell polarization in this process. Importantly, the TFH-like cells operated in IL-21-IFN-γ-dependent pathways to induce plasma cell differentiation and thereby create conditions for M2b macrophage polarization. Thus induction of TFH-like cells links innate inflammation to immune privilege in tumors.