scholarly journals Regulatory interactions between CD45RBhigh and CD45RBlow CD4+ T cells are important for the balance between protective and pathogenic cell-mediated immunity.

1994 ◽  
Vol 179 (2) ◽  
pp. 589-600 ◽  
Author(s):  
F Powrie ◽  
R Correa-Oliveira ◽  
S Mauze ◽  
R L Coffman
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Scid Mice ◽  
Th2 Cells ◽  
Cell Mediated Immunity ◽  
Th1 Cells ◽  
Ifn Gamma ◽  
Th1 Response ◽  
Major Infection

BALB/c mice infected with the intracellular protozoan Leishmania major mount a T helper cell 2 (Th2) response that fails to control growth of the parasite and results in the development of visceral leishmaniasis. Separation of CD4+ T cells into CD45RBhigh and CD45RBlow subsets showed that the L. major-specific Th2 cells were contained within the CD45RBlow population as these cells produced high levels of antigen-specific interleukin 4 (IL-4) in vitro and transferred a nonhealing response to L. major-infected C.B-17 scid mice. In contrast, the CD45RBhighCD4+ population contained L. major-reactive cells that produced interferon gamma (IFN-gamma) in vitro and transferred a healing Th1 response to L. major-infected C.B-17 scid mice. Transfer of the Th1 response by the CD45RBhigh population was inhibited by the CD45RBlow population by a mechanism that was dependent on IL-4. These data indicate that L. major-specific Th1 cells do develop in BALB/c mice, but their functional expression is actively inhibited by production of IL-4 by Th2 cells. In this response, the suppressed Th1 cells can be phenotypically distinguished from the suppressive Th2 cells by the level of expression of CD45RB. Although the CD45RBhigh population mediated a protective response to L. major, C.B-17 scid mice restored with this population developed a severe inflammatory response in the colon that was independent of L. major infection, and was prevented by cotransfer of the CD45RBlow population. The colitis appeared to be due to a dysregulated Th1 response as anti-IFN-gamma, but not anti-IL-4, prevented it. Taken together, the data show that the CD4+ T cell population identified by high level expression of the CD45RB antigen contains cells that mediate both protective and pathogenic Th1 responses and that the reciprocal CD45RBlow population can suppress both of these responses. Whether suppression of cell-mediated immunity is beneficial or not depends on the nature of the stimulus, being deleterious during L. major infection but crucial for control of potentially pathogenic inflammatory responses developing in the gut.

scholarly journals SERPINB10 contributes to asthma by inhibiting the apoptosis of allergenic Th2 cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yuqing Mo ◽  
Ling Ye ◽  
Hui Cai ◽  
Guiping Zhu ◽  
Jian Wang ◽  
...  
Keyword(s):  
T Cells ◽  
Allergic Asthma ◽  
Cd4 T Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Allergic Inflammation ◽  
Specific Ige ◽  
Th2 Cells ◽  
Th1 Cells ◽  
Th2 Response ◽  
Th1 And Th2

Abstract Background Serine peptidase inhibitor, clade B, member 10 (SERPINB10) contributes to allergic inflammation in asthma. However, its role in the T-helper type 2 (Th2) response of allergic asthma is not known. The goal of this study was to unveil the function of SERPINB10 in the Th2 response of allergic asthma and the mechanism by which SERPINB10 affects the viability of Th2 cells. Methods Th2 cytokines and serum levels of house dust mite (HDM)-specific IgE in bronchoalveolar lavage fluid were examined by ELISA in an HDM-induced asthma model. The number and apoptosis of Th1 and Th2 cells in mouse lungs were measured by flow cytometry. Naïve CD4 T cells from patients with asthma were cultured under appropriate polarizing conditions to generate Th1 and Th2 cells. SERPINB10 expression in polarized Th1 and Th2 cells was quantified by real-time reverse transcription-quantitative polymerase chain reaction. SERPINB10 expression was knocked down in human CD4 T cells with lentivirus. Results Knockdown of SERPINB10 expression significantly diminished HDM-induced Th2 cytokine secretion and level of HDM-specific IgE. After HDM exposure, SERPINB10-knockdown mice had diminished numbers of Th2 cells, but similar numbers of Th1 cells, compared with those in negative-control mice. Th2 cells of SERPINB10-knockdown mice were more susceptible to apoptosis than that of control mice. Stimulating T-cell receptors (TCRs) with anti-CD3 antibody caused upregulation of SERPINB10 expression in polarized Th2 cells, but not polarized Th1 cells. Knockdown of SERPINB10 expression resulted in fewer numbers and greater apoptosis of polarized Th2 cells. Conclusion Our results suggest that SERPINB10 may contribute to allergic inflammation and the Th2 response of asthma by inhibiting the apoptosis of Th2 cells.

scholarly journals Interleukin 12 induces stable priming for interferon gamma (IFN-gamma) production during differentiation of human T helper (Th) cells and transient IFN-gamma production in established Th2 cell clones.

1994 ◽  
Vol 179 (4) ◽  
pp. 1273-1283 ◽  
Author(s):  
R Manetti ◽  
F Gerosa ◽  
M G Giudizi ◽  
R Biagiotti ◽  
P Parronchi ◽  
...  
Keyword(s):  
T Cells ◽  
Interferon Gamma ◽  
Specific Antigen ◽  
Th2 Cells ◽  
Interleukin 12 ◽  
T Helper ◽  
Ifn Gamma ◽  
Selection Of

Interleukin 12 (IL-12) facilitates the generation of a T helper type 1 (Th1) response, with high interferon gamma (IFN-gamma) production, while inhibiting the generation of IL-4-producing Th2 cells in polyclonal cultures of both human and murine T cells and in vivo in the mouse. In this study, we analyzed the effect of IL-12, present during cloning of human T cells, on the cytokine profile of the clones. The culture system used allows growth of clones from virtually every T cell, and thus excludes the possibility that selection of precommitted Th cell precursors plays a role in determining characteristics of the clones. IL-12 present during the cloning procedures endowed both CD4+ and CD8+ clones with the ability to produce IFN-gamma at levels severalfold higher than those observed in clones generated in the absence of IL-12. This priming was stable because the high levels of IFN-gamma production were maintained when the clones were cultured in the absence of IL-12 for 11 d. The CD4+ and some of the CD8+ clones produced variable amounts of IL-4. Unlike IFN-gamma, IL-4 production was not significantly different in clones generated in the presence or absence of IL-12. These data suggest that IL-12 primes the clone progenitors, inducing their differentiation to high IFN-gamma-producing clones. The suppression of IL-4-producing cells observed in polyclonally generated T cells in vivo and in vitro in the presence of IL-12 is not observed in this clonal model, suggesting that the suppression depends more on positive selection of non-IL-4-producing cells than on differentiation of individual clones. However, antigen-specific established Th2 clones that were unable to produce IFN-gamma with any other inducer did produce IFN-gamma at low but significant levels when stimulated with IL-12 in combination with specific antigen or insoluble anti-CD3 antibodies. This induction of IFN-gamma gene expression was transient, because culture of the established clones with IL-12 for up to 1 wk did not convert them into IFN-gamma producers when stimulated in the absence of IL-12. These results suggest that Th clones respond to IL-12 treatment either with a stable priming for IFN-gamma production or with only a transient low level expression of the IFN-gamma gene, depending on their stage of differentiation.

scholarly journals Downregulation of miRNA-451a Promotes the Differentiation of CD4+ T Cells towards Th2 Cells by Upregulating ETS1 in Childhood Asthma

2020 ◽  
pp. 1-11
Author(s):  
Tianyue  Wang ◽  
Qianlan Zhou ◽  
Yunxiao Shang
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
Cd4 T Cells ◽  
Peripheral Blood Lymphocytes ◽  
Cell Polarization ◽  
Luciferase Assay ◽  
Th2 Cells ◽  
Th2 Cell ◽  
Novel Target

Children exposed to common aeroallergens may develop asthma that progresses into adulthood. Inflammation regulated by T helper 2 (Th2) cells, a specific subpopulation of CD4+ T lymphocytes, is involved in asthmatic injury. Herein, our microarray data indicated that microRNA-451a-5p (miRNA-451a) expression decreased by 4.6-fold and ETS proto-oncogene 1 (ETS1) increased by 2.2-fold in the peripheral blood lymphocytes isolated from asthmatic children (<i>n</i> = 4) as compared to control individuals (<i>n</i> = 4). The negative correlation between miRNA-451a and ETS1 was further validated in 40 CD4+ T cell samples (10 healthy vs. 30 asthmatic samples). In vitro, naïve CD4+ T cells isolated from control individuals were cultured under Th2 cell polarizing condition. miRNA-451a expression decreased while ETS1 increased in CD4+ T cells in the setting of Th2 cell polarization. Moreover, miRNA-451a knockdown enhanced Th2 cell polarization – cells positive for both GATA3 (GATA binding protein 3, a Th2-transcription factor) and CD4 increased, and the generation of Th2 cell cytokines, interleukin (IL)5 and IL13, increased. In contrast, miRNA-451a overexpression inhibited Th2 cell differentiation. Interestingly, dual-Luciferase assay proved ETS1 as a novel target of miRNA-451a. Moreover, enforced expression of ETS1 partially restored miRNA-451a-induced inhibition of IL5 and IL13, and increased the GATA3+CD4+ cell population. Collectively, our work demonstrates that downregulation of miRNA-451a upregulates ETS1 expression in CD4+ T cells, which may contribute to Th2 cell differentiation in pediatric asthma.

scholarly journals Activation of CD4+ T cells in the presence of a nondepleting monoclonal antibody to CD4 induces a Th2-type response in vitro.

1995 ◽  
Vol 182 (1) ◽  
pp. 5-13 ◽  
Author(s):  
P Stumbles ◽  
D Mason
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Primary Cultures ◽  
In Vitro Experiments ◽  
Ifn Gamma

In vitro experiments using purified rat CD4+ T cells in primary and secondary mixed leukocyte cultures (MLC) have been carried out to explore the mechanism of inhibition of cell-mediated autoimmune disease in the rat by a nondepleting monoclonal antibody (mAb) to CD4. Previous work has shown that W3/25, a mouse anti-rat CD4 mAb of immunoglobulin G1 isotype, completely prevents the development of the paralysis associated with experimental allergic encephalomyelitis (EAE) in Lewis rats, but does so without eliminating the encephalitogenic T cells. The in vitro experiments described in this study have shown that when CD4+ T cells were activated in the presence of the anti-CD4 mAb in a primary MLC, the synthesis of interferon (IFN) gamma, but not interleukin (IL) 2, was completely inhibited. After secondary stimulation, now in the absence of the mAb, the synthesis of IL-4 and IL-13 mRNA was greatly enhanced compared with that observed from CD4+ T cells derived from primary cultures in which the mAb was omitted. As IL-4 and IL-13 are known to antagonize cell-mediated immune reactions, and as EAE is cell-mediated disease, the data suggest that the W3/25 mAb controls EAE by modifying the cytokine repertoire of T cells that respond to the encephalitogen. The capacity for the mAb to suppress IFN-gamma synthesis provides, in part, an explanation for this change in cytokine production. These findings are discussed in terms of what is known of the factors that determine which cytokine genes are expressed on T cell activation. Possible implications for the evolution of T cell responses in human immunodeficiency virus infection are also discussed.

Tofacitinib modulates the VZV-specific CD4+ T cell immune response in vitro in lymphocytes of patients with rheumatoid arthritis

Rheumatology ◽  
2019 ◽  
Vol 58 (11) ◽  
pp. 2051-2060 ◽  
Author(s):  
Giovanni Almanzar ◽  
Felix Kienle ◽  
Marc Schmalzing ◽  
Anna Maas ◽  
Hans-Peter Tony ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Granzyme B ◽  
Janus Kinase ◽  
Cell Immune Response ◽  
Dependent Manner ◽  
Th1 Response

AbstractObjectiveRA is a chronic inflammatory disease characterized by lymphocyte infiltration and release of inflammatory cytokines. Previous studies have shown that treatment with Janus kinase inhibitors, such as tofacitinib, increased the incidence rate of herpes zoster compared with conventional DMARDs. Therefore, this study aimed to investigate the effect of tofacitinib on the varicella-zoster-virus (VZV)-specific T cell immune response.MethodsThe effect of tofacitinib on the VZV-specific T cell immune response was determined by evaluating the IFNγ production, the proliferative capacity, the VZV-induced differentiation into effector and memory T cells, the expression of activation marker CD69 and helper T cell type 1 (Th1)-characteristic chemokine receptors, such as CXCR3 and CCR5, as well as cytotoxic activity (perforin and granzyme B expression) of CD4+ T cells of patients with RA compared with healthy donors upon stimulation with VZV antigen in vitro.ResultsTofacitinib significantly reduced the IFNγ production, proliferation, activation, and CXCR3 expression of VZV-specific CD4+ T cells in a dose-dependent manner in short- and long-term lymphocyte culture. No effect on the distribution of naive, effectors or memory, or on the expression of perforin or granzyme B by VZV-specific CD4+ T cells was observed.ConclusionThis study showed that tofacitinib significantly modulated the Th1 response to VZV. The poor VZV-specific cellular immune response in patients with RA may be considered in recommendations regarding appropriate vaccination strategies for enhancing the VZV-specific Th1 response.

T-Rapa Cell Clinical Products Contain a Balance of Minimally Differentiated Th2/Th1 Effector Cells Depleted of Treg Cells

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 352-352 ◽  
Author(s):  
Miriam E. Mossoba ◽  
Jacopo Mariotti ◽  
Xiao-Yi Yan ◽  
Anu Gangopadhyay ◽  
Mathew Winterton ◽  
...  
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
Cd4 T Cells ◽  
Treg Cells ◽  
Cytokine Secretion ◽  
Th2 Cells ◽  
Th1 Cells ◽  
Cell Secretion ◽  
Th2 Cytokine ◽  
Low Levels

Abstract Abstract 352 Ex-vivo expansion of murine donor CD4+ T cells using co-stimulation, IL-4, and rapamycin generated a T cell population (T-rapa cells) that beneficially modulated GVHD, graft rejection, and GVT effects. We thus conducted a clinical trial to evaluate T-rapa cell infusion after HLA-matched sibling allogeneic HCT. In one trial arm, T-rapa cell infusion (2.5 × 107 cells/kg; d 14 post-HCT) safely accelerated alloengraftment after low-intensity host conditioning, as evidenced by: conversion of mixed chimerism to predominant donor chimerism in the majority of patients by d 100 post-HCT and a low rate of grade II to IV acute GVHD (10%; 4/40 cases). This abstract characterizes the T-rapa clinical products (n=48), particularly with respect to the balance of Th1, Th2, and Treg cells and the magnitude of effector function (cytokine secretion); this latter aspect is relevant because in animal models, T cells of limited differentiation mediate increased in vivo effects upon adoptive transfer. Transplant donors underwent steady-state leukapheresis. CD4+ T cells were then purified (Miltenyi.. CliniMACS) and expanded in Lifecell.. bags for 12 days using co-stimulation (anti-CD3, anti-CD28 coated magnetic beads) and media containing rhIL-2, rhIL-4, and rapamycin. T-rapa products contained minimal cells of naive phenotype (CD45RA+ cells: 2 ± 0.4%) and were comprised of both central memory cells (CCR7+: 28 ± 2%) and effector memory cells (CCR7−: 67 ± 2%). Phenotyping assays were performed on T-rapa clinical products at d 12 of culture (time of cell product infusion); in addition, to assess phenotype stability, assays were performed after an additional 6 days of culture after co-stimulation without IL-4 and rapamycin (“day 18”). For comparison, four separate CD4+ T cell culture conditions were established from each of n=8 normal donors. For these control cultures, CD4+ T cells were co-stimulated and propagated for 12 days in tissue culture flasks using: (1) IL-2, IL-4 (“Th2”); (2) IL-2, IL-4 plus rapamycin (“T-rapa”); (3) IL-2, IFN-a (“Th1”); and (4) IL-2, IFN-a plus rapamycin (“Th1-rapa”). Phenotyping results are shown in Fig. 1. In the four flask cultures, there was modest skewing of the Th2/Th1 balance, as indicated by relatively comparable expression of the Th2 transcription factor GATA-3 and the Th1 transcription factor T-bet by intra-cellular flow cytometry (Fig. 1A). In marked contrast, day 12 T-rapa clinical products expressed a highly polarized Th2/Th1 balance (GATA-3/T-bet ratio of 28 ± 9 [mean ± SEM]); this Th2/Th1 balance was relatively stable after additional culture without IL-4 and rapamycin (“Day 18”). The median frequency of transcription factor expression was 11.5% for GATA-3 (range: 3–37%), 5.1% for T-bet (range: 0–18%), and &lt; 1% expression of the Treg transcription factor FoxP3 (range: 0–0.7%). T-rapa clinical products were evaluated for cytokine secretion in response to co-stimulation at day 12 and day 18 of culture; supernatants were tested for Th2 cytokines (Fig. 1B) and Th1/Th17 cytokines (Fig. 1C). Day 12 T-rapa clinical products secreted each Th2 cytokine measured. The magnitude (pg/ml) of T-rapa cell Th2 cytokine secretion was approximately 2-log reduced relative to control Th2 cells; day 18 T-rapa cell secretion of Th2 cytokines was increased relative to day 12 values, but still reduced relative to control Th2 cells. Day 12 T-rapa clinical products did not secrete IL-17 and secreted low levels of IFN-g, IL-2, and TNF-a (1-3 log reduced relative to Th1 control cells). Day 18 T-rapa cell secretion of IFN-g and TNF-a was increased relative to day 12 values, but still reduced relative to control Th1 cells. Remarkably, day 18 T-rapa cell secretion of IL-2 was greatly diminished relative to day 12 values, and IL-17 secretion remained at minimal levels. In conclusion, T-rapa cell clinical products are comprised of a balance of Th2 and Th1 effector CD4+ T cells, with minimal contamination from Treg or Th17 cells. The T-rapa cell clinical products possessed limited differentiation plasticity and secreted low levels of Th2 and Th1 cytokines. Adoptive transfer of a balance of minimally differentiated and fixed polarity donor Th2/Th1 cells represents a novel approach to safely accelerate alloengraftment after low-intensity conditioning. Disclosures: No relevant conflicts of interest to declare.

Functional Characterization of CD4+ T-Cells in Aplastic Anemia (AA)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1340-1340 ◽  
Author(s):  
Shahram Y Kordasti ◽  
Judith C. W. Marsh ◽  
Sufyan Al-Khan ◽  
Jie Jiang ◽  
Alexander E Smith ◽  
...  
Keyword(s):  
T Cells ◽  
Treatment Group ◽  
High Throughput ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Absolute Number ◽  
Th2 Cells ◽  
Th1 Cells ◽  
Ifn Γ ◽  
Pre Treatment

Abstract Abstract 1340 We have examined the role of CD4+ T-cells in the pathogenesis of AA in 63 patients, 48 of whom were analyzed at diagnosis and 15 following immunosuppressive therapy (IST). Absolute numbers of CD4+ regulatory T cells (Tregs, defined as CD3+CD4+CD25highCD27+Foxp3+) were lower in pre-treatment AA patients compared to 10 healthy donors (HDs) (5.5 × 106 v 1.4 × 107)(p=0.01). In patients with severe (SAA) and very severe AA (VSAA), the absolute number and frequency of Tregs were lower than non-severe AA (NSAA) (4.4 × 106/L v 1 × 107/L)(p=0.01) and HDs (4.4 × 106/L v 3 × 107/L) (p<0.001). Absolute numbers of Th1 and Th2 cells in all pre-treatment patients were higher compared to HDs (6.4 × 107/L v 1.8 × 107/L)(p=0.03) for Th1 and (2.6 × 107/L v 2.4 × 106/L)(p=0.006) Th2 cells. Although mean percentages of AA Th17 cells were higher than in HDs (1.5% v 0.15%)(p=0.04), differences in absolute numbers were not significant. Absolute numbers of Th2 and Th17 cells were increased in SAA (1.3 × 107/L v 7.4 × 106/L for Th2)(p=0.01) compared to NSAA (5.7 × 106/L v 2.15 × 106/L for Th17)(p=0.02). Ratios of Th1/Tregs (p=0.003), Th2/Tregs (p=0.02), and Th17/Tregs (p=0.001) were higher in SAA and VSAA compared to NSAA. Percentage of both activated (CD4+CD45RA−CD25highFoxp3high) and resting (CD4+CD45RA+ CD25highFoxp3low) Tregs was decreased in AA patients, compared to HDs (p=0.004 and p=0.01), whereas cytokine secreting Tregs (CD4+CD45RA−CD25high Foxp3low) were increased in AA (p<0.003). Sorted Tregs from AA patients did not suppress cytokine secretion by autologous or HD T effectors (Te) cells in 1:1 co-cultures, whereas IL-2 and IFN-γ secretion by AA Te (CD4+CD25lowCD127high) was suppressible by allogeneic Tregs from HDs, confirming Tregs dysfunction. AA Tregs did not inhibit either CD154 or CD69 expression on Te cells. Tregs from AA patients secreted significantly more IFN-γ, TNF-α and IL-17 (p=0.02, p=0.02 and p=0.01, respectively) after 4 hours stimulation with PMA/Ionomycine compared to HDs. Expression levels of FoxP3, ROR□c and T-bet in AA Tregs was normal. IFN-γ secreting cells (Th1) were enriched using enrichment kit then further enriched by FACS sorting. CDR3 region products of TCR Vβ-chain were amplified using Vβ specific forward and Cβ reverse primers. CDR3 PCR products from AA patients and HDs were subjected 454 sequencing (Roche GS FLX titanium). Sequencing was performed to yield an average ‘depth’ in excess of 1000 clonally reads (1000x) for each sample specific CDR3 PCR amp icon. Reads were processed using Roche Amp icon Variant Analyzer software (AVA). Diversity of TCR receptors (measured by spectratyping and confirmed by high throughput deep sequencing) in AA Th1 cells was lower than HDs (p=0.037), as shown by the percentage and number of consensus clusters in total sequence reads. Interestingly, percentages of the most dominant CDR3 clones, revealed by high throughput sequencing, were higher in AA compared to HDs, regardless of spectratyping pattern. Global gene expression of Tregs was compared in 3 pre-IST AA patients and 5 HDs. A unique gene signature consisting of 86 genes that were significant was identified. There were 8 down regulated genes (fold change) in the pre-treatment group; PIN4 (−4.1), OR2T12 (−3.3), AMAC1 (−2.73), PERP (−2.69), UTS2 (−2.27), RNF139 (−2.13), COMMD9 (−2.09) and LOC100128356 (−2.01). The top 10 of 78 up-regulated genes in the pre-treatment group were HBB (19.5), PSME2 (13.8), CSDA (13.07), FAM127A (7.78), EXOSC1 (7.73), BPGM (7.43), CYSLTR1 (7.17), CHPT1 (6.96) and PLAC8 (6.71). qPCR analysis for CSDA, HBB, PSMiE2, PERP, PIN4, and UTS2 confirmed a similar trend to the microarray results. Interestingly absolute number of Tregs, and Th2/Treg ratio were higher in 10 IST responsive patients compared to 5 non-responsive patients (p=0.005 and 0.02, respectively). We show that expansion of Th1, Th2, Th17, and decreased/skewed Tregs immunophenotype and function are a consistent and defining feature of SAA and VSAA. Clonal expansion of Th1 cells is likely to be antigen driven and the presence of dysfunctional Tregs aggravates this autoimmune response. Increases of Tregs, and Th2/Treg ratios following IST predicts a favourable response to this treatment. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Resolution of cutaneous leishmaniasis: interleukin 12 initiates a protective T helper type 1 immune response.

1993 ◽  
Vol 177 (6) ◽  
pp. 1797-1802 ◽  
Author(s):  
J P Sypek ◽  
C L Chung ◽  
S E Mayor ◽  
J M Subramanyam ◽  
S J Goldman ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
Enzyme Linked Immunosorbent Assay ◽  
Th1 Cells ◽  
T Helper ◽  
Ifn Gamma ◽  
Lymph Node Cells ◽  
Helper Type

Resistance to Leishmania major in mice is associated with the appearance of distinct T helper type 1 (Th1) and Th2 subsets. T cells from lymph nodes draining cutaneous lesions of resistant mice are primarily interferon gamma (IFN-gamma)-producing Th1 cells. In contrast, T cells from susceptible mice are principally Th2 cells that generate interleukin 4 (IL-4). Although existing evidence is supportive of a role for IFN-gamma in the generation of Th1 cells, additional factors may be required for a protective response to be maintained. A potential candidate is IL-12, a heterodimeric cytokine produced by monocytes and B cells that has multiple effects on T and natural killer cell function, including inducing IFN-gamma production. Using an experimental leishmanial model we have observed that daily intraperitoneal administration at the time of parasite challenge of either 0.33 micrograms IL-12 (a consecutive 5 d/wk for 5 wk) or 1.0 micrograms IL-12 per mouse (only a consecutive 5 d) caused a &gt; 75% reduction in parasite burden at the site of infection, in highly susceptible BALB/c mice. Delay of treatment by 1 wk had less of a protective effect. Concomitant with these protective effects was an increase in IFN-gamma and a decrease in IL-4 production, as measured by enzyme-linked immunosorbent assay of supernatants generated from popliteal lymph node cells stimulated with leishmanial antigen in vitro. The reduction in parasite numbers induced by IL-12 therapy was still apparent at 10 wk postinfection. In addition, we observed that the administration of a rabbit anti-recombinant murine IL-12 polyclonal antibody (200 micrograms i.p. every other day for 25 d) at the time of infection to resistant C57Bl/6 mice exacerbated disease. These effects were accompanied by a shift in IFN-gamma production in vitro by antigen-stimulated lymph node cells indicative of a Th2-like response. These findings suggest that IL-12 has an important role in initiating a Th1 response and protective immunity.

scholarly journals Leishmania promastigotes evade interleukin 12 (IL-12) induction by macrophages and stimulate a broad range of cytokines from CD4+ T cells during initiation of infection.

1994 ◽  
Vol 179 (2) ◽  
pp. 447-456 ◽  
Author(s):  
S L Reiner ◽  
S Zheng ◽  
Z E Wang ◽  
L Stowring ◽  
R M Locksley
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Leishmania Major ◽  
Interleukin 12 ◽  
Insect Vector ◽  
T Helper 1 ◽  
Ifn Gamma ◽  
Effector Cells

Leishmania major are intramacrophage parasites whose eradication requires the induction of T helper 1 (Th1) effector cells capable of activating macrophages to a microbicidal state. Interleukin 12 (IL-12) has been recently identified as a macrophage-derived cytokine capable of mediating Th1 effector cell development, and of markedly enhancing interferon gamma (IFN-gamma) production by T cells and natural killer cells. Infection of macrophages in vitro by promastigotes of L. major caused no induction of IL-12 p40 transcripts, whereas stimulation using heat-killed Listeria or bacterial lipopolysaccharide induced readily detectable IL-12 mRNA. Using a competitor construct to quantitate a number of transcripts, a kinetic analysis of cytokine induction during the first few days of infection by L. major was performed. All strains of mice examined, including susceptible BALB/c and resistant C57BL/6, B10.D2, and C3H/HeN, had the appearance of a CD4+ population in the draining lymph nodes that contained transcripts for IL-2, IL-4, and IFN-gamma (and in some cases, IL-10) that peaked 4 d after infection. In resistant mice, the transcripts for IL-2, IL-4, and IL-10 were subsequently downregulated, whereas in susceptible BALB/c mice, these transcripts were only slightly decreased, and IL-4 continued to be reexpressed at high levels. IL-12 transcripts were first detected in vivo by 7 d after infection, consistent with induction by intracellular amastigotes. Challenge of macrophages in vitro confirmed that amastigotes, in contrast to promastigotes, induced IL-12 p40 mRNA. Reexamination of the cytokine mRNA at 4 d revealed expression of IL-13 in all strains analyzed, suggesting that IL-2 and IL-13 may mediate the IL-12-independent production of IFN-gamma during the first days after infection. Leishmania have evolved to avoid inducing IL-12 from host macrophages during transmission from the insect vector, and cause a striking induction of mRNAs for IL-2, IL-4, IL-10, and IL-13 in CD4+ T cells. Each of these activities may favor survival of the organism.

scholarly journals CD4+ effector cells default to the Th2 pathway in interferon gamma-deficient mice infected with Leishmania major.

1994 ◽  
Vol 179 (4) ◽  
pp. 1367-1371 ◽  
Author(s):  
Z E Wang ◽  
S L Reiner ◽  
S Zheng ◽  
D K Dalton ◽  
R M Locksley
Keyword(s):  
T Cells ◽  
Interferon Gamma ◽  
Knockout Mice ◽  
Leishmania Major ◽  
Interleukin 4 ◽  
Th2 Cells ◽  
Th1 Cells ◽  
Wild Type ◽  
Cd4 Cells ◽  
Ifn Gamma

Mice with homologous disruption of the interferon gamma (IFN-gamma) gene on the C57BL/6 background were infected with Leishmania major and the immune response assessed. In contrast to wild-type or heterozygous knockout mice, deficient animals were unable to restrict growth of the parasite and suffered lethal infection over 6-8 wk. Although wild-type and heterozygous littermates developed CD4+ cells that contained transcripts for IFN-gamma and lymphotoxin, typical of T helper type 1 (Th1) cells, the knockout mice developed CD4+ cells that contained transcripts for interleukin 4 (IL-4), IL-5, and IL-13, typical of Th2 cells. ELISPOT assays confirmed the reciprocal patterns of IFN-gamma or IL-4 production by T cells in similar frequencies in the respective groups of mice, and antibody analysis confirmed the presence of Th2-mediated isotype switching in the knockout mice. These data suggest that CD4+ T cells that normally respond to antigens by differentiation to Th1 cells default to the Th2 pathway in the absence of endogenous IFN-gamma.

Sign in / Sign up

Export Citation Format

Share Document