Role of interleukin-12 in the maturation of naive human CD4 T cells.
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Antigen-Presenting Cells↗
Biomedical subjects
G Delespesse
Publications and source records attributed to G Delespesse.
Functional CD40 ligand expression on T lymphocytes in the absence of T cell receptor engagement: involvement in interleukin-2-induced interleukin-12 and interferon-gamma production.
Despite the fact that the great majority of T cells at the site of an inflammatory response are not antigen specific, the mechanisms leading to activation and recruitment of these bystander T cells are poorly understood. We previously reported that soluble (s)CD23 potentiated the interleukin (IL)-2-induced interferon (IFN)-gamma production by T cells co-cultured with autologous monocytes in the absence of T cell receptor (TCR) engagement. Our present data demonstrate that the IL-2-induced IFN-gamma secretion, in the presence but also in the absence of sCD23, is strictly IL-12 dependent, inasmuch as anti-IL-12 antibody abrogated both responses. Most interestingly, anti-CD40 ligand (CD40L) monoclonal antibody significantly inhibited IL-2-induced IL-12 as well as IFN-gamma production. These results suggest that CD40L was expressed on T cells in the absence of TCR engagement. Indeed, purified unstimulated T cells readily expressed CD40L. IL-2 and monocytes did not up-regulate CD40L on resting T cells. It is proposed that low levels of CD40L expression on non-antigen stimulated T cells are sufficient to signal through CD40 molecules on accessory cells and to induce IL-12 secretion, which in turn can synergize with IL-2 for the induction of IFN-gamma production, thus contributing to the inflammatory process.
Adult↗
Triggering through CD40 promotes interleukin-4-induced CD23 production and enhanced soluble CD23 release in atopic disease.
The pathogenesis of atopic disease is closely linked to the overproduction of IgE. CD23 and CD40 are two cellular receptors involved in the regulation of IgE production and both receptors are elevated in atopic disease. We have examined the role of CD40 in the regulation of CD23 and soluble CD23 production in healthy and atopic donors. Triggering of the B cell CD40 receptor directly enhances interleukin (IL)-4-mediated up-regulation of CD23 at both the protein and the mRNA level. When atopic donors were studied, the synergistic effect of CD40 triggering on the IL-4-induced up-regulation of CD23 and soluble CD23 (sCD23) was enhanced and there was a relative skewing toward production of sCD23. These studies implicate the CD40 receptor in the hyperproduction of CD23 and sCD23 in atopic disease and suggest that abnormalities may exist in the cellular pathways leading to sCD23 production.
Antibodies, Monoclonal↗
CD31 (PECAM-1) is a differentiation antigen lost during human CD4 T-cell maturation into Th1 or Th2 effector cells.
The CD31 antigen (PECAM-1) has been reported to be a stable marker for a human CD4 T-cell subpopulation unable to produce interleukin-4 (IL-4). We show here that CD31 expression is not stable inasmuch as CD4 T-cell lines and clones derived from cell-sorted neonatal CD31+ cells lose CD31 upon repetitive cycles of stimulation and IL-2 expansion. Moreover, various cytokines (IL-1 alpha, IL-4, IL-6, transforming growth factor-beta) fail to reinduce CD31 on CD31- clones. Whereas all CD31+ CD4 T cells rapidly express high levels of the CD45RO antigen and down-regulate the L-selectin antigen after priming, CD31 disappears more slowly because only part of the cells lose CD31 expression upon each cycle of stimulation. Loss of CD31 reflects a functional maturation of CD45RO+ cells since, in a system which favours the development of Th2 effectors, IL-4 is produced by CD31- but not CD31+ effector T cells, whereas interferon-gamma is produced by both types of cells. However, CD31 is not a Th1 marker since it is not expressed on several Th1 antigen-specific clones. We conclude that CD31 is a maturation marker expressed on the great majority of naive CD45RO- CD4 T cells and on a subset of CD45RO+ CD4 T cells that are at an intermediate stage of maturation.
Adult↗
Human Th2-like cell clones induce IL-12 production by dendritic cells and may express several cytokine profiles.
Previous studies have shown that human Th2 cells, unlike their murine counterparts, retain the ability to produce IFN-gamma upon activation in the presence of exogenous IL-12. Here we first extended this notion by showing that Th2-like cell clones (Th2C) are also capable of inducing IL-12 production by physiological antigen-presenting cells (APC); we next showed that these cells may express several distinct cytokine profiles depending upon the activation signal and the type of APC with which they interact. We have analyzed the production of IL-4, IL-5 and IFN-gamma by Th2C stimulated by either anti-CD3 mAb or exogenous IL-2, using peripheral blood monocytes or dendritic cells (DC) as accessory cells. We found that: (I) DC but not monocytes released IL-12 and promoted IL-12-dependent IFN-gamma production upon interaction with anti-CD3- or IL-2-stimulated Th2C and (II) ligation of CD3 was required for the production of IL-4 but not of IL-5 or IFN-gamma. Thus, depending upon the type of APC with which they interacted and the mode of activation, Th2C, expressed four distinct cytokine profiles: (i) IL-4 + IL-5, in response to anti-CD3 + monocytes; (ii) IL-4, IL-5 + IFN-gamma, in response to anti-CD3 + DC; (iii) IL-5 + IFN-gamma, in response IL-2 + DC; and (iv) IL-5 alone, in response to IL-2 + monocytes. The ability of human Th2-like cells to induce IL-12 production and to release the proinflammatory cytokines IFN-gamma and IL-5 upon IL-2-driven interactions with APC may contribute to explain how local infection exacerbates Th2-mediated diseases, like bronchial asthma and atopic dermatitis.
Animals↗
Soluble CD23 directly activates monocytes to contribute to the antigen-independent stimulation of resting T cells.
The majority of T cells at the site of an inflammatory lesion do not appear to be Ag-specific, but they still contribute to the inflammatory response. Herein, we report that sCD23 activates monocytes to participate in the stimulation of resting T cells in the absence of TCR engagement. First, sCD23 selectively triggers monokine release by purified monocytes in the absence of costimulus. It induces TNF-alpha, IL-1 beta, IL-8, granulocyte-macrophage-CSF, and prostaglandin E2 but no IL-10, IL-12, TGF-beta, or leukotriene B4. The sCD23-induced TNF-alpha production is significantly inhibited by IL-4 and IL-10 but not by TGF-beta. Also, monocytes activated by sCD23 express decreased levels of HLA-DR and increased levels of CD14, CD54, CD40, and B7 Ag. Next, we show that, in the presence of monocytes, sCD23 is a potent costimulator of IL-2 or IL-12-induced IFN-gamma production by resting T cells in the absence of exogenous Ag and that this effect is partially reduced by anti-TNF-alpha mAb. B cells cannot substitute for monocytes, and CD4+ and CD8+ T cells are equal responders. The data further indicate that monocyte-T cell contact, more particularly CD40-CD40L interactions, is required for IFN-gamma production in response to IL-2 plus sCD23, and the response to IL-12 plus sCD23 is CD40- and B7-independent but is still partially contact-dependent. It is proposed that sCD23, when produced locally at a site of immune response, may trigger an inflammatory process via monokine release and may further amplify it via the stimulation of bystander non-Ag-specific T cells.
Cells, Cultured↗
Activated T cells induce interleukin-12 production by monocytes via CD40-CD40 ligand interaction.
Previous studies on the production of interleukin-12 (IL-12) have shown that it is released, together with other proinflammatory cytokines, shortly after exposure of phagocytic cells to a variety of pathogens. We here report that IL-12 is also released during the recall response to soluble antigen (Ag) devoid of intrinsic adjuvant activity. We show that activated T cells induce the production of IL-12 by monocytes via a mechanism involving the interaction of T cell-associated CD40 ligand with CD40 on monocytes. The data suggest that Ag presentation on monocytes favors the persistence of type 1 responses.
Antigen Presentation↗
Human naive CD4 T cells produce interleukin-4 at priming and acquire a Th2 phenotype upon repetitive stimulations in neutral conditions.
The maturation of naive CD4 T cells into interleukin (IL)-4-producing effectors was shown to require the presence of IL-4 at priming, the cellular origin of which remains unclear. We demonstrate here that naive T cells themselves release IL-4 at very low levels that are nevertheless sufficient to promote their development into Th2-like cells. This conclusion is based on three observations: (1) highly purified human naive CD4 T cells, of neonatal or adult origin, develop into Th2 effectors upon repetitive cycles of stimulation with anti-CD3 monoclonal antibody (mAb) cross-linked to CD32-B7 transfected L fibroblasts followed by IL-2 expansion; (2) IL-4 protein is readily detectable in the concentrated supernatant fluids of priming cultures performed in the presence of anti-IL-4 receptor mAb; and (3) addition of anti-IL-4 or anti-IL-4 receptor mAb at priming markedly inhibits the acquisition of IL-4- and IL-5-producing capacity while enhancing that of interferon-gamma.
Adult↗
Default development of cloned human naive CD4 T cells into interleukin-4- and interleukin-5- producing effector cells.
It was recently demonstrated that naive human and mouse CD4 T cells release low but sufficient levels of interleukin (IL)-4 at priming to support their development into IL-4 producers. To determine whether this IL-4 is produced by a minor subset of cells, freshly isolated human naive CD4 T cells were directly cloned by limiting dilution in the absence of exogenous IL-4. More than 95% of neonatal and 60% of adult naive T cells seeded in single-cell cultures could be expanded upon stimulation with anti-CD3 mAb immobilized on CD32-B7.1 L cell transfectants in the presence of IL-2. All 171 clones derived from four neonates and two adults produced IL-4 and IL-5 at generally high levels. Like the allergen-specific human Th2 clones described in the literature, these T cell clones produced little or no interferon-gamma upon stimulation via their T cell receptor/CD3 complex, whereas they released high levels of this cytokine when activated with phorbol 12-myristate 13-acetate+ionomycin. Cells cloned and expanded in the presence of anti-IL4 + anti-IL-4R mAb produced much lower levels of IL-4 and IL-5. It is concluded that almost every single naive human CD4 T cell primed and expanded in the absence of exogenous IL-4 releases sufficient autocrine IL-4 to support its clonal expansion into high IL-4/IL-5 producers.
Adult↗
Maturation of neonatal human CD4 T cells: III. Role of B7 co-stimulation at priming.
We previously reported that human naive CD4 T cells differentiate into effector cells producing type 1 (IL-2, IFN-gamma) and type 2 (IL-4, IL-5, IL-10) cytokines after priming with anti-CD3 mAb presented on irradiated CD32-transfected mouse L fibroblasts, in the absence of exogenous cytokine. Here we first show that the CD32 L fibroblasts act not only by cross-linking anti-CD3 mAb but also by providing a B7-mediated co-stimulation signal which is required for the activation of naive T cells. Using a selected anti-CD3 mAb (64.1) we next demonstrate that colligation of CD3 and CD28 with soluble mAb is sufficient to activate highly purified naive CD4 T cells for proliferation, IL-4 mRNA expression, IL-4 secretion, and maturation into IL-4- and IL-5-producing cells. Finally, we show that the intensity of B7 co-stimulation at priming markedly affects the lymphokine-producing phenotype of primed cells. Indeed, cells primed on CD32-B7 double L transfectants produce much more IL-4 and IL-5 and slightly less IFN-gamma than those primed on CD32 L cells. The enhanced IL-4/IL-5-producing capacity of cells primed on CD32-B7 L fibroblasts may be related to increased IL-4 production during priming. It is suggested that the maturation of naive T cells along the Th2 or Th1 pathway may be regulated by the level of B7 expressed on APC.
Animals↗
The two CD23 isoforms display differential regulation in chronic lymphocytic leukaemia.
B lymphocytes from chronic lymphocytic leukaemia (B-CLL) patients express the two CD23 isoforms (type A and B), which differ only in their intracytoplasmic domain. The abnormal regulation of the CD23 antigen in response to IL-4, IFNs alpha and gamma results in CD23 over-expression on B-CLL cells. Our present study shows that the two CD23 isoforms are differentially and abnormally regulated on B-CLL cells. IL-4 selectively up-regulates CD23 type A mRNA in five different B-CLL patients, whereas in normal B cells it enhances CD23 type A and is the most potent inducer of type B. In contrast, phorbol esters (PMA) up-regulate both CD23 isoforms in the malignant B cells and specifically increases type B in normal B cells. We next postulated that cytokines other than IL-4 regulate CD23 B isoform in B-CLL cells and therefore examined the effect of IL-2, IFN-gamma and IFN-alpha. We found that the ability of a given cytokine to induce B-CLL growth (i.e. IL-2 and IFN alpha) is concurrent with a selective up-regulation of CD23 type B mRNA, whereas lymphokines that have no B cell growth activity (i.e. IL-4 and IFN-gamma) specifically increase CD23 type A mRNA. We next showed that IL-4 and IFN gamma prevent hydrocortisone-induced programmed cell death and that the rescued malignant B cells mainly express CD23 type A. Given that CD23 molecule has been reported to play a role in normal B cell proliferation and survival, it is therefore proposed that in B-CLL cells the expression of CD23 type A may be related to cell viability and that of type B to cell proliferation. These data suggest that the CD23 molecule may contribute to the physiopathology of the disease which is characterized by the accumulation of long-lived and slow-dividing monoclonal B cells.
Adult↗
IL-2 and IL-7 but not IL-12 protect natural killer cells from death by apoptosis and up-regulate bcl-2 expression.
Human natural killer cells (NK) respond to interleukin-2 (IL-2) with augmented cytolytic activity, cytokine secretion and cell proliferation. Here we show that IL-2 protects NK cells from death by apoptosis (programmed cell death; PCD). Highly purified NK cells (CD3- CD56+) were isolated from peripheral blood lymphocytes (PBL) of either control donors or of an asymptomatic donor with 60% NK cells. Glucocorticosteroids (GCS) induced PCD in NK cells, as shown by nuclear condensation and DNA fragmentation. IL-2 completely prevented GCS-induced PCD in a dose-dependent manner without overcoming GCS-induced inhibition of NK cell proliferation. The IL-2 protective effect was mediated through the p75 beta chain of the IL-2R, as neutralizing monoclonal antibody (mAb) to the p75 beta chain but not to the p55 alpha chain completely abolished the IL-2 anti-apoptotic activity. In addition to IL-2, the cytokines IL-7 and IL-12 have been reported to regulate NK cell functions. Our present data showed that IL-7 but not IL-12 rescued NK cells from apoptosis, but to a lesser extent than IL-2. Although IL-4 had a marginal protective effect, IL-1, IL-3, IL-6, IL-8, interferon-gamma (IFN-gamma) and IFN-alpha, tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and granulocyte-macrophage colony-stimulating factor (GM-CSF) displayed no significant activity. Finally, we report that IL-2 and IL-7 enhanced bcl-2 expression in NK cells, suggesting the existence of a bcl-2-dependent survival pathway. In addition to regulating various functions, it is concluded that IL-2 and IL-7 have the ability to prevent PCD in NK cells.
Apoptosis↗
In vitro maturation of neonatal human CD8 T lymphocytes into IL-4- and IL-5-producing cells.
Naive CD8 T cells isolated from umbilical cord blood were examined for cytokine production and for surface phenotype before and after priming with anti-CD3 mAb in the presence of selected cytokines. On stimulation with anti-CD3 immobilized on CD32-B7-transfected L cells, naive and primed CD8 T cells release high levels of IFN-gamma but no IL-2, IL-4, or IL-5. IL-12-primed cells, and to a lesser extent IL-2-primed cells, have an increased capacity to produce IFN-gamma but display the same restricted pattern of cytokine production. Cells primed in the presence of IL-4 or IL-4 + IL-2 are capable of producing high levels of IL-5 but no IL-4, and their IFN-gamma-producing capacity is much reduced. Cells primed with both IL-4 + IL-12 produce high levels of IL-5 and IFN-gamma but no IL-4. IL-4-producing CD8 T cells are obtained only if IL-4- or IL-4 + IL-2-primed cells are subjected to a second cycle of activation in the presence of IL-2; restimulation of IL-4 + IL-12-primed cells under identical conditions fails to generate IL-4-producing cells but leads to the development of high IFN-gamma and IL-5 producers. Thus, unlike in CD4 T cells, IL-12 completely inhibits IL-4-induced capacity of CD8 T cells to produce IL-4. However, IL-4 and IL-12 synergize to promote the expression of IL-5. Regardless of the priming conditions, primed CD8 T cells are CD45ROhigh/RA-, CD31high and more than 50% are CD4+/CD8+; activated naive or primed CD8 T cells do not express CD40 ligand.
CD3 Complex↗
Role for low-affinity receptor for IgE (CD23) in normal and leukemic B-cell proliferation.
CD23 gene is overexpressed and abnormally regulated in the most frequent adult leukemic disorder, B chronic lymphocytic leukemia (B-CLL). Switch on and off in the upregulation of surface CD23 expression consistently occurs in the early stage of normal B-cell activation, suggesting a key role for CD23 in this process. We show here that, after ligation of mlg in the presence of interleukin-4, the increase of CD23 protein precedes B-cell DNA synthesis and mainly results from the strong induction of CD23 type-B isoform. Exposure of normal B cells to conventional or phosphorothioate-derivatized CD23 antisense oligonucleotides (predominantly type B) significantly augments B-cell proliferation induced by antigen receptor stimulation or direct contact with activated T cells. Unexpectedly, CD23 antisense, but not sense, oligonucleotides specifically enhance rather than suppress CD23 expression on B cells. Finally, a selective increase in CD23 type-B expression provokes the entry of resting (Go) CLL B cells into G1 and S phase of the cell cycle in the absence of any other stimulus, whereas it synergizes with tumor necrosis factor-alpha to increase the number of activated B cells. These results provide compelling evidence that CD23 represents an important molecule directly involved in the process of normal or leukemic B-cell activation and growth.
Base Sequence↗
Regulation of cytokine production by soluble CD23: costimulation of interferon gamma secretion and triggering of tumor necrosis factor alpha release.
Soluble CD23 (sCD23) has multiple IgE-independent biological activities. In the present study, we examined the regulatory effect of sCD23 on cytokine production by human peripheral blood mononuclear cells (PBMC). We show that sCD23 enhances by about 80-fold the interleukin 2 (IL-2)-induced interferon gamma (IFN-gamma) production and by about 10-fold the response to IL-12. This potentiating activity is time and dose dependent and is not associated with a significant effect on DNA synthesis. The sCD23 costimulatory activity for IFN-gamma synthesis is drastically reduced in monocyte-depleted PBMC, suggesting that monocytes may be the target for sCD23. This hypothesis was supported by the following observations. First, sCD23 alone is a potent inducer of tumor necrosis factor alpha (TNF-alpha) production by PBMC and this effect disappears after monocyte depletion. The triggering of TNF-alpha release is specifically inhibited by neutralizing anti-CD23 monoclonal antibody (mAb). In addition, IL-2 and IL-12 synergize with sCD23 to induce TNF-alpha production. Second, sCD23 triggers the release of other inflammatory mediators such as IL-1 alpha, IL-1 beta, and IL-6. Finally, TNF-alpha production in response to IL-2 and sCD23 precedes IFN-gamma and IFN-gamma secretion is significantly inhibited by anti-TNF-alpha mAb, indicating that the sCD23 costimulatory signal for IFN-gamma production may be partially mediated by TNF-alpha release. It is proposed that sCD23 is a proinflammatory cytokine that, in addition, may play an important role in the control of the immune response via the enhancement of IFN-gamma production.
Cells, Cultured↗
In vitro maturation of human neonatal CD4 T lymphocytes. II. Cytokines present at priming modulate the development of lymphokine production.
The development of naive CD4 T cells into type 1 or type 2 Th cells has been extensively analyzed in the mouse. Using neonatal CD4 T lymphocytes as a source of human naive cells, we report that these cells may be induced to differentiate into effector cells producing predominantly Th1 or Th2 cytokines. After 3 days of stimulation with anti-CD3 mAb immobilized on CD32 transfected mouse fibroblasts, followed by 3 days of culture in the presence of IL-2, neonatal cells acquire the phenotypic and functional characteristics of effector cells. Primed cells are enriched in CD45R0hi and CD31- cells, and upon stimulation with PMA+ ionomycin they release significant amounts of IL-2, IFN-gamma, IL-4, IL-5, and IL-10. Addition of exogenous cytokines during the period of activation with anti-CD3 markedly alters the profile of cytokine production by primed cells: 1) IL-2 uniformly enhances Th1 and Th2 cytokine production; 2) IL-4 markedly enhances the release of IL-4, IL-5, and IL-10 and suppresses that of IFN-gamma; 3) IFN-gamma strongly inhibits IL-4 and IL-5 production but slightly enhances IFN-gamma release; 4) IFN-alpha markedly inhibits IL-4 and IL-5 production and increases the production of both IFN-gamma and of IL-10; 5) TGF-beta suppresses IL-4 and IL-5 (and to a lesser extent IL-2) production but has inconsistent effect on IL-10 and IFN-gamma production. These effects of exogenous cytokines are not associated with an alteration of CD31 expression on primed cells.
Animals↗
Regulation of CD23 expression by IL-4 and corticosteroid in human B lymphocytes. Altered response after EBV infection.
Cellular CD23 has been implicated in various biologic and pathologic processes. Here, we have studied the regulation of B cell CD23 expression and function by the synthetic corticosteroid, dexamethasone (DEX). We report that DEX acts directly on B lymphocytes to down-regulate IL-4-induced CD23 expression, whereas in parallel the IL-4R is up-regulated. Down-regulation of CD23 occurred at the cell surface and for shed material in culture medium. EBV infection of B cells is linked to development of lymphoproliferative diseases, including lymphoma, and there is evidence that EBV-stimulated CD23 expression may be instrumental in the inappropriate survival of infected cells. We have determined that treatment of EBV-infected cells with IL-4 leads to a synergistic up-regulation of B cell CD23. Furthermore, infection of B cells by EBV introduced a relative resistance to the down-regulatory effects of DEX on IL-4-induced CD23 expression.
B-Lymphocytes↗