scholarly journals IL-21-Mediated Generation of Human Regulatory B Cells Occurs Independently of CD40 Signaling

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1413-1413
Author(s):  
Bernd Jahrsdörfer ◽  
Christof Kaltenmeier ◽  
Ali Gawanbacht ◽  
Thamara Beyer ◽  
Catharina Schütz ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Third Party ◽  
Immunological Methods ◽  
Regulatory B Cells ◽  
T Helper ◽  
Regulatory Phenotype

Abstract Recently, we and others found that B cells differentiate into regulatory B cells (Breg) in response to interleukin (IL-)21. Of note, the key characteristic of human IL-21-induced Breg is expression of the serine protease granzyme B (GrB), whereas murine Breg, which require both IL-21 and CD40 ligand (CD40L) for their induction, predominantly express the immunosuppressive cytokine IL-10. Using two different disease models and various immunological methods, we further characterized the conditions leading to Breg differentiation in humans. Here, we demonstrate that in humans CD40L determines whether IL-21 induces differentiation of B cells into plasma cells (CD40L presence) or into GrB+ Breg (CD40L absence), which can directly control T cell proliferation by GrB-dependent degradation of the T cell receptor z-chain. Furthermore, we show that GrB+ Breg are circulating at high frequencies in the peripheral blood of untreated, highly viremic HIV patients, but not in healthy subjects. Of note, HIV-infected CD4+ T cells express IL-21, but not CD40L, and induce a GrB+ regulatory phenotype in healthy third party B cells in vitro. Consequently, addition of CD40L multimers can compensate for this insufficient T helper cell function, resulting in increased plasma cell/Breg ratios. Moreover, we investigated a patient with a congenital defect of Nuclear-Factor-kappa-B-Essential-Modulator (NEMO), which is essential for normal CD40 signaling. Even in the presence of viral infections, when CD4+ T helper cells from such patients are highly activated with strong expression of IL-21, they are not able to establish sufficient antibody responses. Instead, we found this patient to almost exclusively harbor B cells with a regulatory phenotype including high basal levels of GrB. When untreated NEMO B cells were co-cultured with allogeneic T cells from a healthy third party donor, these T cells failed to proliferate and to survive in response to a 6-day stimulation with anti-CD3/CD28 antibodies, an effect not observed with B cells from healthy donors. Since NEMO B cells lack normal CD40 signaling, our findings unequivocally demonstrate that in contrast to murine Breg IL-21-dependent induction of human Breg can occur in a CD40-independent fashion. Disclosures No relevant conflicts of interest to declare.

Immune Characteristics Associated with Lymphomatoid Granulomatosis and Outcome Following Treatment with Interferon-Alpha

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 963-963 ◽  
Author(s):  
Kieron Dunleavy ◽  
Pratip Chattopadhyay ◽  
Junichi Kawada ◽  
Sara Calattini ◽  
Emma Gostick ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Complete Remission ◽  
Interferon Alpha ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Lymphomatoid Granulomatosis ◽  
Grade Iii

Abstract Abstract 963 Lymphomatoid granulomatosis (LYG) is a rare angiocentric/angiodestructive EBV+ B-cell lymphoproliferative disorder. LYG has a spectrum of clinical aggressiveness and histological grading. Grading relates to the number of EBV-positive B-cells with grade I /II being usually polyclonal or oligoclonal and grade III monoclonal. Historical outcomes of patients treated with steroids and/or chemotherapy have been poor with median survivals of 14 months. We have shown that LYG is associated with reduced CD8+ and CD4+ T-cells, and hypothesized that patients have defective immune surveillance of EBV+ B-cells. We are investigating the use of interferon-alpha (IFα) for grade I/II disease and have characterized the maturation, exhaustion, and homeostatic potential of bulk and antigen-specific CD8 T-cells. Patients with grade III disease are treated with DA-EPOCH-R. Characteristics of 53 patients on study include male sex 68%; median age (range) 46 (17-67) and median ECOG P.S. 1 (0-3). Disease sites include lung 98%, CNS 38%, kidney 15%, skin 17% and liver 19%. LYG grades are I –30%, II-26% and III-44%. Prior treatment was none –28%, chemotherapy+/− R-34% and steroids alone – 40% of patients. Herein, we report the outcome of patients with grade I/II LYG treated with IFα. IFα was commenced at 7.5 MIU TIW and dose escalated until best response and then continued for 1 year. Of 31 patients with grade I/II LYG treated with IFα, 28 were evaluable for response. Of these, 17 (60%) achieved a complete remission and 6 (21%) patients progressed with grade III disease and received chemotherapy. Of 10 patients with CNS disease, 9 achieved a CR with IFα. At a median follow-up time of 5 years, the progression-free survival of grade I/II LYG was 56%. The median time to remission was 9 months (3-40) and median IFα dose was 20 MIUs (7-40). Median EBV viral loads at study entry were 18 copies/106 genome equivalents (0-22727) (normal<200). We looked at T-cell kinetics in patients who achieved complete remission and observed statistically significant recovery in both CD4 (p=0.034) and CD8 p=0.034) cells after interferonα. We were interested in further elucidating T-cell function and used polychromatic flow cytometry to characterize CD8 T-cells in the peripheral blood of patients before and after IFα. In 17 patient samples, cells were stained with peptide-MHC I (pMHCI) multimers directed against T-cells specific for epitopes from latent and lytic EBV proteins along with antibodies defining CD8 sub-populations. Influenza or cytomegalovirus-specific pMHCI multimers were controls. We observed no difference in the frequency of EBV specific CD8 T-cells in the blood of LYG patients compared to controls. However, CD27 and PD1 expression appeared to be altered in the bulk CD8+ T-cells and in selected EBV-specific populations in LYG patients; these changes were marginally significant. Following completion of IFα, expression of PD-1, CD27 and CD127 were at normal levels. Evidence from some LYG patients suggests that IL2 production by EBV-specific T-cells is lost during LYG, and normalized after therapy. Our results suggest that LYG, an EBV-associated disease, may arise in the setting of a global deficit in CD8 T-cells with selected defects in EBV-specific immunity that resolve with successful therapy. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The role of H-2-linked genes in helper T cell function. VII. Expression of I region and immune response genes by B cells in bystander help assays.

1980 ◽  
Vol 152 (5) ◽  
pp. 1274-1288 ◽  
Author(s):  
P Marrack ◽  
J W Kappler
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Function ◽  
High Responder ◽  
Helper T Cells ◽  
Spleen Cells ◽  
Region Gene ◽  
Immunoglobulin Receptor

The mode of action by bystander helper T cells was investigated by priming (responder X nonresponder) (B6A)F1 T cells with poly-L-(Tyr, Glu)-poly-D,L-Ala--poly-L-Lys [(TG)-A--L] and titrating the ability of these cells to stimulate an anti-sheep red blood cell (SRBC) response of parental B cells and macrophages in the presence of (TG)-A--L. Under limiting T cell conditions, and in the presence of (TG)-A--L, (TG)-A--L-responsive T cells were able to drive anti-SRBC responses of high-responder C57BL/10.SgSn (B10) B cells and macrophages (M0), but not of low-responder (B10.A) B cells and M0. Surprisingly, the (TG)-A--L-driven anti-SRBC response of B10.A B cells was not restored by addition of high-responder acessory cells, in the form of (B6A)F1 peritoneal or irradiated T cell-depleted spleen cells, or in the form of B10 nonirradiated T cell-depleted spleen cells. These results suggested that (TG)-A--L-specific Ir genes expressed by B cells controlled the ability of these cells to be induced to respond to SRBC by (TG)-A--L-responding T cells, implying that direct contact between the SRBC-binding B cell precursor and the (TG)-A--L-responsive helper T cells was required. Analogous results were obtained for keyhold limpet hemocyanin (KLH)-driven bystander help using KLH-primed F1 T cells restricted to interact with cells on only one of the parental haplotypes by maturing them in parental bone marrow chimeras. It was hypothesized that bystander help was mediated by nonspecific uptake of antigen [(TG)-A--L or KLH] by SRBC-specific b cells and subsequent display of the antigen on the B cell surface in association with Ir of I-region gene products, in a fashion similar to the M0, where it was then recognized by helper T cells. Such an explanation was supported by the observation that high concentrations of antigen were required to elicit bystander help. This hypothesis raises the possibility of B cell processing of antigen bound to its immunoglobulin receptor and subsequent presentation of antigen to helper T cells.

scholarly journals Potential Impact of B Cells on T Cell Function in Multiple Sclerosis

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sara Ireland ◽  
Nancy Monson
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Function ◽  
The Central Nervous System ◽  
Potential Impact ◽  
Anti Cd20 ◽  
The Impact ◽  
Ms Pathogenesis

Multiple sclerosis is a chronic debilitating autoimmune disease of the central nervous system. The contribution of B cells in the pathoetiology of MS has recently been highlighted by the emergence of rituximab, an anti-CD20 monoclonal antibody that specifically depletes B cells, as a potent immunomodulatory therapy for the treatment of MS. However, a clearer understanding of the impact B cells have on the neuro-inflammatory component of MS pathogenesis is needed in order to develop novel therapeutics whose affects on B cells would be beneficial and not harmful. Since T cells are known mediators of the pathology of MS, the goal of this review is to summarize what is known about the interactions between B cells and T cells, and how current and emerging immunotherapies may impact B-T cell interactions in MS.

scholarly journals Inhibition of normal B-cell function by human immunodeficiency virus envelope glycoprotein, gp120

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1245-1254 ◽  
Author(s):  
N Chirmule ◽  
N Oyaizu ◽  
VS Kalyanaraman ◽  
S Pahwa
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Function ◽  
Cell Contact ◽  
Cell Proliferation And Differentiation ◽  
Cell Clones ◽  
Glycoprotein Gp120

Abstract Despite the occurrence of hypergammaglobulinemia in human immunodeficiency virus (HIV) infection, specific antibody production and in vitro B-cell differentiation responses are frequently impaired. In this study, we have examined the effects of HIV envelope glycoprotein gp120 on T-helper cell function for B cells. In the culture system used, B-cell functional responses were dependent on T-B- cell contact, since separation of T and B cells in double chambers by Transwell membranes rendered the B cells unresponsive in assays of antigen-induced B-cell proliferation and differentiation. Cytokines secreted by T cells were also essential, since anti-CD3 monoclonal antibody (mAb)-activated, paraformaldehyde-fixed T-cell clones failed to induce B-cell proliferation and differentiation. Pretreatment of the CD4+ antigen-specific T cells with gp120 was found to impair their ability to help autologous B cells, as determined by B-cell proliferation, polyclonal IgG secretion, and antigen-specific IgG secretion. The gp120-induced inhibition was specific in that it was blocked by soluble CD4. Furthermore, only fractionated small B cells (which are T-cell-dependent in their function) manifested impaired responses when cultured with gp120-treated T cells. Antigen-induced interleukin (IL)-2 and IL-4, but not IL-6, secretion were markedly reduced in gp120-treated T-cell clones. Addition of exogenous cytokines failed to compensate for defective helper function of gp120-treated T cells. The findings in this study indicate that gp120 impairs helper functions of CD4+ T cells by interfering with T-B-cell contact- dependent interaction; the inhibitory effects of soluble envelope proteins of HIV may contribute to the immunopathogenesis of the HIV- associated disease manifestations.

Identification of a Discrete Subpopulation of T-Cells Over-Expressing HDAC11 with a TH17 Phenotype

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 588-588
Author(s):  
Karrune Woan ◽  
Fengdong Cheng ◽  
Hongwei Wang ◽  
Jennifer Rock-Klotz ◽  
Zi Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Negative Regulator ◽  
Egfp Expression ◽  
In Vivo Models

Abstract Abstract 588 We recently defined a novel role of histone deacetylase 11 (HDAC11), the newest member of the HDAC family, as a negative regulator of IL-10 gene transcription in antigen-presenting cells (APCs).1 To better understand the role of HDAC11 gene expression in immune cells in vivo, we have utilized a BAC (Bacterial artificial chromosome) transgenic mouse in which the EGFP reporter gene was inserted downstream of the HDAC11 promoter region but immediately upstream of the HDAC11 coding sequence (TgHDAC11-EGFP mice).2 In the steady-state, macrophages and B-cells isolated from spleen of TgHDAC11-EGFP mice express low levels of HDAC11 as evidenced by a slight shift in EGFP fluorescence from background. In sharp contrast, we identified a discrete population (11.9%) of T-cells over-expressing HDAC11 as demonstrated both by flow cytometry for EGFP and by qRT-PCR for HDAC11, a majority of which were CD4+ T-cells. Sorting of this EGFP+, CD4+ T-cell population confirmed that the increased EGFP expression correlated with an increased HDAC11mRNA expression. Reminiscent of our prior data in APCs, the increased expression of HDAC11 in T-cells was also inversely correlated with IL-10mRNA expression. Further analyses revealed that in the absence of any stimulation or T-cell polarizing conditions, this EGFP positive population expressed significantly elevated levels of ROR-γt and IL-17 mRNA, markers specific for the TH17 subpopulation. Polarization of wild type CD4+ T-cells into functional TH17 cells was associated with reduction of HDAC11 expression, suggesting a potential role for HDAC11 in regulating T-cell function and/or activation, in particular within the TH17 subset. Further support for this regulatory role of HDAC11 has been provided by our additional findings that T-cells devoid of HDAC11 are indeed hyper-reactive in vitro and in in vivo models. 1. Villagra A, et al. Nat Immunol. 2009 Jan;10(1):92-100. 2. Gong S, et al. Nature. 2003 Oct 30;425(6961):917-25. Disclosures: No relevant conflicts of interest to declare.

Impact of Lenalidomide on Gene Expression Profiles of Malignant and Immune Cells in Patients with Chronic Lymphocytic Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 976-976 ◽  
Author(s):  
John C. Riches ◽  
Ajanthah Sangaralingam ◽  
Shahryar Kiaii ◽  
Tracy Chaplin ◽  
Demet Cekdemir ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Family Member ◽  
Cell Function ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Lymphocytic Leukemia ◽  
Healthy Donors

Abstract Abstract 976 Lenalidomide has recently been demonstrated to have significant activity in chronic lymphocytic leukemia (CLL). Its mechanism of action in this disease is not well understood, but it is thought to act primarily by enhancing anti-tumor immunity and reducing production of pro-tumoral factors in the CLL microenvironment. We have previously demonstrated alterations in the expression of cytoskeletal genes in T-cells from patients with CLL and have subsequently shown that these changes translate into a deficit in T-cell function, due to impaired actin polymerization resulting in defective immunological synapse formation. Treatment of both autologous T-cells and CLL cells with lenalidomide was necessary to repair this defect, suggesting that this may be a key component of this agent's activity in CLL. Therefore we examined the effect of lenalidomide on the global gene expression profiles of isolated B-cells and T-cell subsets from CLL patients and healthy donors. Peripheral blood mononuclear cells from patients with untreated CLL or healthy donors were cultured in the presence of 1 μM lenalidomide or vehicle control for 48 hours. The lymphocyte subsets were isolated, followed by RNA extraction and gene expression profiling using the Affymetrix HGU133Plus2.0 platform. Lenalidomide treatment had similar effects on gene expression in T-cells from both patients with CLL and healthy donors. The most prominent changes in expression were of genes involved in cytoskeletal signaling including a 20-fold increase in WASF1 (Wiskott Aldrich Syndrome protein family, member 1), and greater than 2-fold increases in the expression of Rac-family member RHOC, (Ras homolog gene family, member C), actin binding proteins CORO1B (Coronin 1B), PARVA (Parvin alpha), and the Rho guanine nucleotide exchange factors (GEFs), ARHGEF5 and ARHGEF7. We also observed changes in genes regulating integrin signaling including PXN (Paxilin) and FAK (Focal adhesion kinase), and a shift towards Th1 differentiation with upregulation of TNF, IL-12R, and IL-18R. In addition, we noted increased expression of the transcription factors IKZF1, IKZF4 and IRF4, genes involved in the Ikaros pathways that are essential for hematopoiesis and control of lymphoid proliferation. These changes in gene expression provide further evidence that an important mechanism of action of lenalidomide is the upregulation of the actin cytoskeletal network including Rho-GTPases and integrin activation signaling, and are consistent with our previous observations concerning the functional repair of T-cells in CLL. Initial analysis of the effect of lenalidomide on the gene expression profiles of the CLL B-cells showed similar changes to those previously described in vivo from CLL patients receiving single agent lenalidomide in a clinical trial (Chen et al. JCO 2010). In our system, lenalidomide treatment resulted in a greater than 2-fold upregulation of 189 genes, and a greater than 2-fold downregulation of 85 genes in CLL B-cells. We observed increased expression of several genes belonging to the TNF superfamily including TNF-α, OX40L, and APRIL, and the receptors DR5, DCR2, and OX40. Many of these are known to mediate apoptosis signaling, and we also observed increased expression of pro-apoptotic genes such as FAS, BID (BH3 interacting domain death agonist), HRK (Harakiri), and CFLAR (CASP8 and FADD-like apoptosis regulator), and cell cycle regulators CDKN1A and CDKN1C (Cyclin-dependent kinase inhibitors 1A and 1C). Lenalidomide also upregulated expression of several genes of known importance in the CLL microenvironment, including the chemokines CCL3 and CCL4, CD40, CD274 (PD-L1), CD279 (PD-1), and adhesion molecules LFA3 and ICAM1. The effect of lenalidomide on the gene expression profiles of normal B-cells was less marked, with greater than 2-fold upregulation of 51 genes and downregulation of 12 genes. However, we did observe that lenalidomide treatment induced upregulation of genes involved in cytoskeletal pathways such as RND1 (Rho family GTPase 1), RHOQ (Ras homolog gene family, member Q), and MYO1B (myosin 1B). In conclusion, investigation of the effect of lenalidomide on gene expression profiling in CLL suggests that the drug acts both to enhance T-cell function, and to render the CLL cells more susceptible to immune cell mediated killing. Disclosures: Gribben: Roche: Honoraria; Celgene: Honoraria; GSK: Honoraria; Mundipharma: Honoraria; Gilead: Honoraria; Pharmacyclics: Honoraria.

Antibodies from Donor B Cells Are Not Required for Initiating but Required for Persisting Scleroderma in Chronic Gvhd

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3817-3817
Author(s):  
Hua Jin ◽  
Xiong Ni ◽  
Ruishu Deng ◽  
James Young ◽  
Heather F Johnston ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Conflicts Of Interest ◽  
Chronic Gvhd ◽  
Cell Interaction ◽  
Spleen Cells ◽  
Littermate Control ◽  
Inflammatory Status

Abstract We recently reported that in a chronic graft versus host disease (GVHD) model of DBA/2 donor to MHC-matched BALB/c recipient, donor CD4+ T and B cell interaction resulted in not only hyperglobulinemia and glomerulonephritis but also scleroderma (J. Immunol. 2012). It is well known that glomerulonephritis is caused by immune complex deposition. However, the role of antibodies from donor B cells in the pathogenesis of scleroderma remains unclear. To address this question, we generated DBA/2 mice whose B cells have APC function but cannot secrete antibodies by backcrossing IgHµg1 mice from Dr. Rajewsky’s lab (JEM 2007). We observed that, while transplanting T-cell-depleted bone marrow (TCD-BM) and spleen cells from littermate control mice induced proteinuria and scleroderma, transplanting BM and spleen cells from IgHµg1 DBA/2 mice induced no proteinuria, but the recipients developed scleroderma ~35 days after HCT. Interestingly, the scleroderma gradually recovered ~55 days after HCT. 40 days after HCT, scleroderma recipients transplanted with WT spleen cells (Rec-WT) or recipients transplanted with IgHµg1 spleen cells (Rec-IgHµg1) both had high percentage (~12%) of IFN-g+ or IL-17+ CD4+ T cells in the peripheral lymph node (PLN) and skin tissues, as compared to that (~3%) of GVHD-free recipients given TCD-BM alone (Rec-TCD). While Rec-WT had severe reduction of CD4+CD8+ thymocytes, the Rec-IgHµg1 had no reduction of the thymocytes, as compared to that of Rec-TCD. By day 60 after HCT, the Rec-WT with ongoing scleroderma still had ~10% IFN-g+ or IL-17+ CD4+ T cells in the PLN and skin tissues; in contrast, although the Rec-IgHµg1 with reversal of scleroderma still had >10% IFN-g+or IL-17+ CD4+ T cells in the PLN, those cells in the skin had reduced to <2%. This reduction was associated with DC upregulation of B7H1 and T cell upregulation of PD-1. These results suggest that antibodies from B cells are required for maintaining inflammatory status of tissue DCs and persistence of scleroderma in chronic GVHD. (This work was supported by NIH R01 AI066008). Disclosures No relevant conflicts of interest to declare.

scholarly journals B cells modulate T cells so as to favour T helper type 1 and CD8+T-cell responses in the acute phase of Trypanosoma cruzi infection

Immunology ◽  
2007 ◽  
Vol 122 (4) ◽  
pp. 584-595 ◽  
Author(s):  
Fabiola Cardillo ◽  
Edilberto Postol ◽  
Jorge Nihei ◽  
Luiz S. Aroeira ◽  
Auro Nomizo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Trypanosoma Cruzi ◽  
Cd8 T Cell ◽  
T Helper ◽  
Cell Responses ◽  
Cruzi Infection ◽  
Helper Type

scholarly journals The histocompatibility restrictions on macrophage T-helper cell interaction determine the histocompatibility restrictions on T-helper cell B-cell interaction.

1978 ◽  
Vol 148 (5) ◽  
pp. 1171-1185 ◽  
Author(s):  
U Yamashita ◽  
E M Shevach
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Interaction ◽  
T Helper Cell ◽  
Helper T Cells ◽  
T Helper ◽  
Ia Antigens ◽  
Nominal Antigen

To study the histocompatibility restriction between macrophages and helper T cells, carrier primed guinea pig T cells were positively selected in vitro with antigenpulsed macrophages for 7 days and the selected T cells were then mixed with hapten-primed B cells and stimulated with antigen in a modified Mishell-Dutton system. Helper T cells could only be selected with syngeneic, but not allogeneic, antigen-pulsed macrophages and would then collaborate only with syngeneic, but not allogeneic, hapten-primed spleen cells. When F1 T cells were selected with antigen-pulsed parental macrophages they would only collaborate with B cells of the same parental strain as the macrophages used in the selection culture. These results are strongly in support of the view that the primed T cell is activated by carrier determinants of the nominal antigen in association with Ia antigens on macrophages and the helper T cell, in turn, activates B cells which bear the same Ia antigens and determinants of the nominal antigen bound to immunoglobulin receptors on their surface. In addition, in experiments with antigens the response to which is controlled by I-linked genes, we demonstrated that primed (responder X nonresponder)F1 T cells would only collaborate with B cells of the responder parent. The defect appeared to be at the level of the B cell in that the addition to the cultures of antigen-presenting cells of the responder type did not restore the ability of F1 T cells to collaborate with non-responder B cells.

Defective T-helper cell function after T-cell–depleting therapy affecting naive and memory populations

Blood ◽  
2002 ◽  
Vol 99 (11) ◽  
pp. 4053-4062 ◽  
Author(s):  
Andreas Heitger ◽  
Patricia Winklehner ◽  
Petra Obexer ◽  
Johannes Eder ◽  
Claudia Zelle-Rieser ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Mononuclear Cells ◽  
Cell Function ◽  
Interleukin 2 ◽  
T Helper Cell ◽  
Helper Cell ◽  
High Dose ◽  
T Helper

Impaired T-cell function after T-cell– depleting (TCD) therapy has been hypothesized to be related to a transient predominance of extrathymically expanding memory T cells. To test whether after TCD therapy the naive T-helper cell population is functionally intact, the in vitro immune response of CD4+CD45RA+ (naive) and of CD4+CD45RA− (memory) cells to polyclonal mitogens (immobilized anti-CD3, phytohemagglutinin) was analyzed by flow cytometry in 22 pediatric patients after high-dose chemotherapy (including 5 after autologous and 5 after allogeneic stem cell support). At 1 to 3 months after TCD therapy, patient samples showing decreased lymphoproliferative responses also showed a reduced induction of the early activation marker CD69 by CD4+ T cells from 4 to 72 hours after stimulation even when supplemented with exogenous interleukin-2. This defect affected CD4+CD45RA− cells, but, strikingly, also CD4+CD45RA+ cells, including samples in which CD4+CD45RA+ cells were more than 90/μL, thus indicating ongoing thymopoiesis. Histogram analyses showed the median peak channel of CD69 in control CD4+CD45RA+cells rising 98-fold (median) but only 28-fold in patient cells (P &lt; .0001). Apoptosis as detected by annexin V staining was increased in resting patient CD4+ T cells (25% versus 6%) and also affected CD4+CD45RA+ cells (12% versus 5%, P &lt; .01). When peripheral blood mononuclear cells (PBMCs) were enriched for T cells, stimulatory responses of CD4+ cells and of CD4+CD45RA+ cells markedly improved. Thus, after TCD therapy suppressor factors contained in the non–T-cell fraction of PBMCs may affect T-helper cells irrespective of their naive or memory phenotype thus extending T-cell dysfunction to the presumably thymus-dependently regenerated T cells.

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