Th2-type Cytokine Secretion Research Articles

Elocalcitol Inhibits Inflammatory Responses in Human Thyroid Cells and T Cells

T-helper 1 (Th1) cell-mediated inflammatory responses predominate in the early pathogenesis of Graves' disease (GD), whereas Th2 cell-mediated immunity may play a role in later stages. The chemokine CXCL10 and its receptor CXCR3 are expressed in most thyroid glands of early GD patients. Circulating CXCL10 levels inversely correlate with disease duration; CXCL10 maximal expression also correlates with interferon (IFN)gamma levels in recent GD onset. Methimazole (MMI) reduces CXCL10 secretion by isolated thyrocytes, decreases serum CXCL10 levels, and promotes a transition from Th1 to Th2 dominance in patients in GD active phase. Vitamin D receptor agonists exhibit antiinflammatory properties and promote tolerance induction. We investigated the effects and the mechanism of action of a nonhypercalcemic vitamin D receptor agonist, elocalcitol (BXL-628), compared with MMI on CXCL10 secretion induced by proinflammatory cytokines. Furthermore, we studied the effects of both drugs on Th1, Th17, and Th2 cytokine secretion in CD4+ T cells. ELISA, cytometry, immunocytochemistry, Western blot, and quantitative real-time PCR were used for protein and gene analysis. In human thyrocytes, elocalcitol inhibited IFNgamma and TNFalpha-induced CXCL10 protein secretion more potently than MMI. Elocalcitol impaired both cytokine intracellular pathways, whereas MMI was effective only on the IFNgamma pathway. In CD4+ T cells, elocalcitol decreased Th1- and Th17-type cytokines, and promoted Th2-type cytokine secretion. Elocalcitol and MMI inhibited Th1 cytokine-mediated responses in thyrocytes and CD4+ T cells. In addition, elocalcitol promoted a shift toward a Th2 response. In conclusion, elocalcitol could represent a novel pharmacological tool in the treatment of autoimmune thyroid diseases.

Potential Role of NK Cells in the Induction of Immune Responses: Implications for NK Cell–Based Immunotherapy for Cancers and Viral Infections

Natural killer (NK) cells recognize tumor cells and virus-infected cells and attack without being sensitized to antigens. The development of the antitumor/antivirus activities of NK cells is controlled by multiple mechanisms such as direct cytotoxic activity against target cells, antibody-dependent cell-mediated cytotoxicity, secretion of Th1-type cytokines, and interactions with dendritic cells. The development of these activities plays a significant role in both innate and adaptive immunities. Considering the recent progress made in elucidating the molecular and cellular biology of NK cells, we summarize the current situation and discuss future possibilities with regard to NK cell–based adoptive immunotherapy.

Immunoregulatory factors in multiple sclerosis patients during and after pregnancy: relevance of natural killer cells

Multiple sclerosis (MS) ameliorates typically during pregnancy but after the delivery the relapse rate often increases. Our study was conducted to understand the immunoregulatory mechanisms accompanying this phenomenon. MS patients were followed-up prospectively during pregnancy and 6 months postpartum, with immunological characterization of the peripheral blood. Groups of age- and parity-matched healthy pregnant women, and age- and sex-matched non-pregnant women and non-pregnant MS patients were studied as controls. In our patient cohort, the annualized relapse rate was 1.0 +/- 1.0 relapses/woman/year (mean +/- standard deviation) during the year before pregnancy, but dropped to 0.2 +/- 0.9 during the third trimester (P = 0.02). After the delivery the relapse rate increased again to 1.4 +/- 1.9 (1-3 months postpartum versus third trimester P = 0.003). While percentages of peripheral blood CD3, CD4, CD8 and CD19 immune cell subsets were unchanged over the observation period, reduced disease activity during the last trimester was associated with a significant increase in the percentage of circulating CD56(bright) natural killer (NK) cells. Simultaneously, the proportion of circulating CD56(dim) NK cells was clearly reduced. No alteration was noted in CD4+ CD25(high) forkhead box P3+ regulatory T cells. Production of interferon-gamma by peripheral blood lymphocytes was down-regulated significantly during pregnancy in comparison to the postpartum period, resulting in an increased T helper type 2 (Th2) : Th1 ratio during pregnancy. In conclusion, pregnant state in MS patients is characterized by an increase in the percentage of CD56(bright) NK cells and by enhanced Th2 type cytokine secretion. Our findings suggest a potential role for CD56(bright) regulatory NK cells in the control of autoimmune inflammation during pregnancy in MS.

Role of immunoregulator factors in the modulation of maternal-alloresponse to fetal antigens: Implications in recurrent pregnancy failures

Toll-like receptor (TLR) 9, recognizing different ligands, confers distinct features of plasmacytoid dendritic cells (pDCs). Our previous study demonstrated a role for TLR9 in the mechanism of experimental autoimmune neuritis (EAN). In this study, we explored whether suppressive oligodeoxynucleotides (sODN) could induce tolerogenic pDCs via TLR9 and thus promote the recovery of EAN. Effects of different TLR9 ligands, CpG ODN and sODN on P0180–199 peptide-stimulated pDCs were measured by detecting the expression of co-stimulatory molecules, indoleamine 2,3-dioxygenase (IDO), secretion of Th1- and Th2-type cytokines and the TLR9 signaling pathway. CpG ODN- or sODN-treated pDCs were intravenously injected into the EAN mice and their effects were compared. Our data showed that P0180–199 peptides significantly promoted mRNA expression of co-stimulatory molecules (CD40, CD80 and CD86) in pDCs and induced secretion of Th1-type cytokines. Treatment of CpG ODN aggravated the effects of P0180–199 peptides on pDCs; however, sODN had the opposite effects and significantly upregulated the IDO expression in pDCs. Further analysis showed that MYD88 is necessary for sODN to modulate the TLR9/NF-κB signaling in pDCs. Finally, the sODN-treated pDCs significantly promoted recovery of the EAN mice. Taken together, sODN could induce tolerogenic pDCs and thus ameliorate the EAN.

IL-6 stimulates Th2 type cytokine secretion and upregulates VEGF and NRP-1 expression in pancreatic cancer cells

BACKGROUND. Although upregulation of interleukin-6 (IL-6) is associated with many solid tumors, its role in pancreatic cancer has not been well elucidated. In this study, we examined the expression of IL-6 in pancreatic cancer cells, and determined the effect of exogenous IL-6 on cytokine secretion, gene expression, and signaling in human pancreatic cancer cells. METHODS. The mRNA levels of IL-6, VEGF165, neuropilin-1 (NRP-1), and neuropilin-2 (NRP-2) were determined by real-time RT PCR. Phosphorylation of ERK2 in pancreatic cancer cells was determined by using Bio-Plex phosphoprotein assay. The expression of IL-6 and other cytokines in human pancreatic cancer cell lines was determined with Bio-Plex cytokine assay. RESULTS. Pancreatic cancer cell lines expressed higher levels of IL-6 than normal human pancreatic ductal epithelium (HPDE) cells. Exogenous IL-6 increased the secretion of multiple Th2 type of cytokines in Panc-1, MIA PaCa-2, and BxPC-3 cells. IL-6 also upregulated the expression of VEGF165, and NRP-1, and both IL-6 and VEGF165 were inducible by hypoxia. In addition, IL-6 activated ERK2 signaling pathways in pancreatic cancer cells. CONCLUSIONS. IL-6 may be involved in promoting human pancreatic cancer development by furnishing Th2 type of cytokine environment and upregulating cell proliferation and angiogenesis related genes. Targeting IL-6 might be an effective treatment for pancreatic cancer.

Ovalbumin modified by gamma irradiation alters its immunological functions and allergic responses

It is well known that gamma (γ)-ray irradiation results in the alteration of biological function of bioactive materials such as proteins, saccharides and lipids. In this study the effect of γ-irradiation on the chemical and immunological property of an allergen, ovalbumin (OVA), was investigated. Irradiation of more than 10 kGy resulted in the alteration of the structure of OVA. However, OVA treated with 10 kGy irradiation (10 kGy-OVA), but not 100 kGy-OVA, fully maintained immunological reactivity to a monoclonal antibody specific to the intact allergen (clone 14). Mice immunized with 10 kGy- as well as 100 kGy-OVA showed significantly lower antibody response to the allergen than those with intact OVA in a γ-ray dosage-dependent manner. Especially immunization of both 10 kGy- and 100 kGy-OVA induced a significant decrease of OVA-specific IgE. Splenocytes of mice immunized with irradiated OVA showed a significant reduction in OVA-specific T cell proliferation and the secretion of Th1-type (IFN-γ and IL-2) and Th2-type cytokines (IL-4 and IL-6). The expression of T cell activation markers such as CD25 and CD44 was also down-regulated in T cells of mice immunized with irradiated OVAs. These results suggest that γ-ray irradiation of OVA suppress humoral and cellular immune responses specific to the allergen OVA, and the modification method with γ-irradiation may be available for the control of allergy.

Lenalidomide (CC5013, Revlimid®) Alters a T Cell Homeostatic Check-Point in Patients with Myelodysplastic Syndrome (MDS).

Background: Myelodysplastic Syndromes (MDS) are a diverse group of myeloid malignancies that occur primarily in older individuals. Several distinct immunologic abnormalities have been described in MDS, including concurrent autoimmune diseases, inversion of CD4+ and CD8+ cell populations, and expansion hematopoietic inhibitory) CD8+ T cell clones. Suppression of hematopoiesis by T cells has been implicated in the pathogenesis of ineffective hematopoiesis in a select subpopulation of patients with response to immunosuppressive therapy. Immunologic abnormalities in MDS patients may relate to the process of immunologic aging associated with functional deterioration. Lenalidomide (CC5013, Revlimid®, Celgene Inc) is a member of a proprietary drug class known as immunomodulatory drugs (IMiDs) with strong and sustained hematological activity in MDS patients. The goal of this study was to investigate the in vitro and in vivo actions of lenalidomide on T cell immune functions and homeostasis in MDS patients.Methods: Using peripheral blood mononuclear cells (PBMCs), we analyzed T cell subpopulations and function in 11 MDS patients and 12 controls of similar age. Naïve and memory CD4 and CD8 T cell sub-populations were segregated by expression of CD45RA and CD62L expression by flow cytometry. After antigen activation with anti-CD3-cross-linking and allogeneic dendritic cells (allo-DCs), T cell proliferation was assessed by Brdu incorporation in CD4+ and CD8+ T cells, and intracellular cytokines determined by flow cytometry. T cell receptor (TCR) repertoire skewing was determined by CDR3-length analysis on 53 patients. In vivo action of lenalidomide was evaluated in PBMCs from seven patients (4 erythroid complete responders and 3 non-responders) taken pre- and post-treatment.Results: Patients with MDS had reduced T cell proliferation and impaired Th1 cytokine response after antigen stimulation compared to age-matched controls. No correlation was found between patient age and percentage of proliferating antigen-induced CD4− or CD8− T cells (r=0.13, p=0.6 and r=−0.17, p=0.5, respectively). Phenotype analysis showed that the percentage of CD4+ and CD8+/CD45RA+/CD62L+−naïve T cells were significantly reduced, whereas, CD4+ and CD8+/CD45RA−/CD62L−double-negative effector memory cells were significantly increased in MDS patients. Furthermore, 50% of MDS patients displayed a skewed T cell receptor repertoire that was not age-dependent. Of the MDS patients treated with lenalidomide, the four responders displayed a significant increase in antigen-induced T cell proliferation and increased Th1-type cytokine secretion, whereas no changes were observed in non-responders. Moreover, CD4+ (P=0.001) and CD8+ (P=0.06) T cells with a naïve phenotype increased accompanied by augmentation in the percentage of CD8+ central memory T cells (P=0.02); whereas, the percentage of CD4+ effector memory cells decreased (p=0.001) in lenalidomide responders but not in non-responders.Conclusions: These data suggest that MDS patients possess multiple T cell defects including age-independent TCR repertoire skewing, reduction in naïve T cells, and accumulation of effector memory cells that are improved by lenalidomide. Our findings suggest hematopoietic response to lenalidomide may relate to a novel capacity to restore T cell homeostasis.

Whole recombinant yeast-based immunotherapy induces potent T cell responses targeting HCV NS3 and Core proteins

Control of primary infection with hepatitis C virus (HCV) is associated with robust and broad T cell immunity. In contrast, chronic infection is characterized by weak T cell responses suggesting that an approach that boosts these responses could be a therapeutic advance. Saccharomyces cerevisiae is an effective inducer of innate and adaptive cellular immunity and we have generated recombinant yeast cells (GI-5005) that produce an HCV NS3-Core fusion protein. Pre-clinical studies in mice showed that GI-5005 induced potent antigen-specific proliferative and cytotoxic T cell responses that were associated with Th1-type cytokine secretion. In studies in which GI-5005 was administered up to 13 times, no detectable vector neutralization or induction of tolerance was observed. Prophylactic as well as therapeutic administration of GI-5005 in mice led to eradication of tumor cells expressing HCV NS3 protein. Immunotherapy with GI-5005 is being evaluated in chronic HCV infected individuals in a Phase 1 clinical trial.

The mutant leucine-zipper domain impairs both dimerization and suppressive function of Foxp3 in T cells.

Regulatory T cells that express the Foxp3 transcription factor play important roles in preventing autoimmune diseases. Although several studies have demonstrated that the lack of the forkhead DNA-binding domain of Foxp3 caused severe autoimmune disease in scurfy mutant mice, the other functional domains of Foxp3 are less well characterized. Here, we show that the deletion of glutamic acid (DeltaE250) in the leucine-zipper domain of Foxp3 causes a loss of hyporesponsiveness when compared with wild-type Foxp3 upon antigenic stimulation. CD4 T cells that ectopically express the glutamic acid mutant show significant losses of suppressor activity both in vitro and in vivo. We also demonstrate that regulation of both Th1- and Th2-type cytokine secretion in CD4 T cells that express wild-type Foxp3 is significantly altered by the deletion of glutamic acid. Defects are also observed in the expression of adhesion molecules, such as l-selectin (CD62L) and CD103, suggesting an important role of glutamic acid in the migratory behavior of regulatory T cells. Finally, this mutation reduces transcriptional repressor activity and impairs the homodimerization of Foxp3. Taken together, our results provide insight into the mechanism that controls autoimmune diseases via the deletion of this single glutamic acid residue in the leucine-zipper domain of Foxp3.

Adoptive transfer of in vitro generated T cell precursors improves T cell reconstitution and mediates graft-versus-tumor activity without graft-versus-host disease in allogeneic hematopoietic stem cell transplantation recipients

Immunoincompetence after allogeneic hematopoietic stem cell transplantation (HSCT) particularly affects the T cell lineage resulting in significant morbidity and mortality from opportunistic infections. Recent studies have shown that murine T cells and their precursors can be generated from hematopoietic stem cells (HSC) in vitro using OP9 bone marrow stromal cells (H2Kk/H2Kb) expressing the Notch 1 ligand Delta-like 1 and growth factors. In this study we determined the effects of adoptively transferred in vitro generated T cell precursors on T cell reconstitution after allogeneic HSCT. We selected HSC (Lin-Sca-1hi c-kit+) from mouse bone marrow (BM) of various strains and cultured these cells on a monolayer of OP9-DL1 cells in the presence of growth factors. T lineage cell development proved to be strain independent and is therefore not MHC restricted in this culture system. C57BL/6 dervied HSC expanded 2000–5000-fold within 3–4 weeks and consisted of 90–95% CD4-CD8-double negative (DN) T cell precursors after 16–28 days of culture. We infused these cells (8 ×106) with T cell depleted (TCD) BM (5 × 106) or purified HSC into allogeneic recipients using minor antigen mismatched and MHC class I/II mismatched transplant models. Progeny of OP9-DL1 derived T cell precursors were found in the thymus and the periphery significantly improving thymic cellularity, and thymic and splenic donor T cell chimerism. Combination of T cell precursor administration and pre-conditioning with keratinocyte growth factor (KGF) further improved thymic engraftment of OP9-DL1 derived T cell precursors. T cell receptor repertoire and proliferative response to foreign antigen of OP9-DL1 derived mature T cells were intact. Moreover, Th1-type cytokine secretion of OP9-DL1 derived splenic T cells after stimulation with PMA/ionomycin was better than that of BM or HSC derived donor T cells. Progeny of OP9-DL1-derived T cell precursors remained detectable for at least 60 days after transplant with intact cytokine production. Administration of in vitro generated T cell precursors did not induce GVHD but mediated significant graft-versus-tumor (GVT) activity (determined by in vivo bioluminescence imaging) resulting in a subsequent significant survival benefit. We conclude that the adoptive transfer of OP9-DL1 derived T cell precursors significantly enhances donor T cell reconstitution in allogeneic HSCT recipients and results in GVT activity in the absence of GVHD.

Altered collagen II peptides inhibited T-cell activation in rheumatoid arthritis

It has been reported that collagen II (CII)-derived peptide induced T-cell activation via its amino acids responsible for T-cell receptor (TCR) recognition. In this study, three altered CII263–272 peptide ligands (APL) containing multiple substitutions of TCR contact residues were synthesized. Their roles in inhibition of T-cell activation were evaluated in peripheral blood lymphocytes (PBL) of rheumatoid arthritis (RA) in vitro. It was shown that 41% (25/61) of RA patients were responsive to the wild-type antigenic CII263–272. In contrast, marginal or silent T-cell responses to the three APLs were found, accompanied by inhibitory effects on secretion of Th1 type cytokines and expression of cell surface markers, CD69 and CD25. In addition, T-cell activation induced by the wild-type antigenic CII263–272 was inhibited by all the three APLs in a dose-dependent manner. It is demonstrated that APLs with substitutions of TCR contact residues are capable of down-regulating T-cell responses in PBLs of RA, suggesting that the CII-derived APLs are potentially therapeutic in RA.

Efficient Induction of Th1-type Immune Responses to Hepatitis B Virus Antigens by DNA Prime-Adenovirus Boost

Chronic infection with hepatitis B virus (HBV) affects about 350 million people worldwide, which have a high risk of development of cirrhosis and hepatocellular carcinoma. Treatment of chronic HBV infection relies on IFN-α or lamivudine. However, interferon-α is effective in only about 30% of patients. Also, the occurrence of escape mutations limits the usage of lamivudine. Therefore, the development and evaluation of new compounds or approaches are urgent. Methods: We comparatively evaluated DNA and adenoviral vaccines expressing HBV antigens, either alone or in combined regimens, for their ability to elicit Th1-type immune responses in Balb / c mice which are believed to be suited to resolve HBV infection. The vaccines were tested with or without a genetically engineered IL-12 (mIL-12 N220L) which was shown to enhance sustained Th1-type immune responses in HCV E2 DNA vaccine. Results: Considering the Th1-type cytokine secretion and the IgG2a titers, the strongest Th1-type immune response was elicited by the DNA prime-adenovirus boost regimen in the presence of mIL-12 N220L. In addition, the codelivery of mIL-12 N220L modulated differentially the immune responses by different vaccination regimens. Conclusion: Our results suggest that the DNA prime-adenovirus boost regimen in the presence of mIL-12 N220L may be the best candidate for HBV vaccine therapy of the regimens tested in this study and will be worthwhile being evaluated in chronic HBV patients.

Infant Vitamin D Supplementation and Allergic Conditions in Adulthood: Northern Finland Birth Cohort 1966

Allergen-induced secretion of Th2-type cytokines and IgE production have recently been reported to be increased in mice treated with 1,25(OH)(2)D, the active form of vitamin D. Our objective was to investigate whether vitamin D supplementation in infancy is associated with the risk of atopy, allergic rhinitis, and asthma. The Northern Finland Birth Cohort consists of all individuals in the two most northern provinces of Finland who were due to be born in 1966. Data on vitamin D supplementation during the first year of life was obtained in 1967. Current asthma and allergic rhinitis were reported at age 31 years (n = 7,648), and atopy determined by skin-prick test in a sub-sample still living in northern Finland or the Helsinki area (n = 5,007). The prevalence of atopy and allergic rhinitis at age 31 years was higher in participants who had received vitamin D supplementation regularly during the first year compared to others (OR 1.46, 95%CI 1.4-2.0, and OR 1.66, 95%CI 1.1-1.6, respectively). A similar association was observed for asthma (OR 1.35, 95%CI 0.99-1.8). These associations persisted after adjustment for a wide range of behavioral and social factors (adjusted: OR 1.33 for all, P = 0.01 for atopy, P = 0.001 for allergic rhinitis, and P = 0.08 for asthma). We observed an association between vitamin D supplementation in infancy and an increased risk of atopy and allergic rhinitis later in life. Further study is required to determine whether these observations reflect long-term effects on immune regulation or differences in unmeasured determinants of vitamin D supplementation.

CD45 Knockout Mice, Diet, and Colitis: In the Absence of CD45, Colitis Follows Dietary Changes

Healthy CD45 KO mice show a Th2-type cytokine secretion profile in their small intestines. Dietary supplementation with human infant formula induced colitis and a shift toward a Th1-type profile, suggesting that diet can alter cytokine secretion.

Genes of tolerance.

Activation-induced cell death, anergy and/or immune response modulation by T-regulatory cells (T(Reg)) are essential mechanisms of peripheral T-cell tolerance. There is growing evidence that anergy, tolerance and active suppression are not entirely distinct, but rather, represent linked mechanisms possibly involving the same cells and multiple suppressor mechanisms. Skewing of allergen-specific effector T cells to T(Reg) cells appears as a crucial event in the control of healthy immune response to allergens and successful allergen-specific immunotherapy. The T(Reg) cell response is characterized by abolished allergen-induced specific T-cell proliferation and suppressed T helper 1 (Th1)- and Th2-type cytokine secretion. In addition, mediators of allergic inflammation that trigger cAMP-associated G-protein coupled receptors, such as histamine receptor 2 may contribute to peripheral tolerance mechanisms. The increased levels of interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) that are produced by T(Reg) cells potently suppress immunoglobulin E (IgE) production, while simultaneously increasing production of noninflammatory isotypes IgG4 and IgA, respectively. In addition, T(Reg) cells directly or indirectly suppress effector cells of allergic inflammation such as mast cells, basophils and eosinophils. In conclusion, peripheral tolerance to allergens is controlled by multiple active suppression mechanisms. It is associated with regulation of antibody isotypes and effector cells to the direction of a healthy immune response and opens a window for novel therapies of allergic diseases.

Promotion of corneal allograft survival by the induction of oxidative macrophages.

A Th1-type immune response was detected in allotransplanted, rejected corneas. Because the intracellular thiol redox status of antigen-presenting cells (APCs) reportedly regulates the Th1/Th2 balance through distinctive cytokine production by APCs, this study was conducted to investigate the effect of the intracellular thiol redox status of macrophages (Mps) on corneal allograft survival. N,N'-diacetyl-L-cystine dimethylester (NACOMe)(2) was injected intraperitoneally into BALB/c (H-2(d)) mice to induce Mps with a low intracellular glutathione content (icGSH). Corneal grafts from C57BL/10 (H-2(b)), B10.D2 (H-2(d)), and DBA/2 (H-2(d)) donor mice were placed on neovascularized BALB/c graft beds for assessment. B10.D2-grafted recipients were evaluated for donor-specific delayed-type hypersensitivity (DTH), and the cytokines produced by their lymphocytes were examined (IFN-gamma, IL-4, and IL-10). In other experiments, naïve BALB/c mice, injected intravenously with Mps of low icGSH content, received B10.D2 corneal grafts. In (NACOMe)(2)-treated mice, 13 of 20 B10.D2 grafts and 6 of 10 DBA/2 grafts survived indefinitely. No grafts survived in the control mice (P < 0.0001). (NACOMe)(2) treatment did not enhance C57BL/10 graft survival. At 2 weeks after B10.D2 grafting, control mice exhibited DTH, but (NACOMe)(2)-treated mice did not (P < 0.01). Lymphocytes from (NACOMe)(2)-treated mice did not respond to donor splenocytes. Those of control mice showed Th1-type cytokine secretion. The intravenous transfer of peritoneal Mps from (NACOMe)(2)-treated mice prolonged corneal allograft survival (P < 0.003). The observed enhanced graft acceptance may be due to the suppression of alloantigen-induced Th1 polarization through the induction of Mps with reduced icGSH levels.

Effect of chondroitin sulfate on murine splenocytes sensitized with ovalbumin

Chondroitin sulfate (CS) is a glycosaminoglycan that is widely present in animals organisms, and it has anti-inflammatory and chondroprotective properties. To examine the effects of CS on the immune system, splenocytes obtained from ovalbumin (OVA)-sensitized BALB/c mice were challenged with OVA in the presence of CS, and cytokine levels in the medium of the cultured cells were measured. CS induced secretion of Th1-type cytokines (IFN-γ, IL-2, and IL-12) by OVA-sensitized splenocytes but suppressed secretion of Th2-type cytokines (IL-5 and IL-10). Flow cytometric assay showed a significantly higher percentage of helper T cells (CD4 +CD8 − cells) among the splenocytes cultured with OVA and CS than with OVA alone. Analysis of the IFN-γ mRNA level of the splenocytes by the real-time quantitative RT-PCR technique revealed higher levels in the splenocytes cultured with OVA and CS than in the splenocytes cultured with OVA alone. This is the first demonstration that CS inhibits antigen-induced IgE production through induction of cytokine secretion by Th1 cells, and this finding suggests a potential use of CS in preventing IgE-mediated allergy.

Characterization of Th1/Th2 Profile in Uremic Patients

End-stage renal failure (ESRD) induces a clinical state of immunodeficiency with a higher incidence of infections and a higher mortality due to infectious complications compared with the normal population. Using a newly developed immunofluorescent staining of intracellular cytokines for flow cytometric analysis, we studied Th subsets in 22 healthy control subjects, 28 patients with compensated chronic renal failure (CRF), 25 patients on hemodialysis (HD), and 24 patients on continuous ambulatory peritoneal dialysis (CAPD). Our results demonstrate that the percentage of both interferon-γ-positive cells and interleukin-4-positive cells increased in compensated CRF patients compared with those in healthy subjects. Moreover, a significantly higher percentage of CD4-positive cells is characterized by a Th1-type cytokine production pattern in HD patients and by a Th2-type cytokine secretion pattern in CAPD patients. These results suggest that the altered Th1/Th2 balance may be associated with the pathogenesis of ESRD.

Genetic Immunization Maps T Cell (Auto)Immune Responses to Self Antigens Homologous to Exogenous Proteins

Genetic immunization represents a new tool for investigating physiological and pathological immune responses. Here we used genetic immunization with naked DNA to study the immune relevance of aminoacid sequence homologies by evaluating the outcome of immunization to a viral protein homologous to an HLA molecule. The viral protein was Balf2, a protein of Epstein-Barr virus (EBV) that shares aminoacid sequence homology with the HLA allele DRB1*0801. After genetic immunization of BALB/c mice with a construct encoding Balf2, we analyzed T cell responses of immunized mice. We found that cross-reactive proliferative and cytotoxic responses were raised to the homologous sequence as expressed by HLA-DRB1*0801. Furthermore, preferential secretion of Th1-type pro-inflammatory cytokines occurred. This strategy can allow rapid screening of interactive immune networks involving aminoacid sequence homologies between organisms.

Antigen presentation by Peyer's patch cells can induce both Th1- and Th2-type responses depending on antigen dosage, but a different cytokine response pattern from that of spleen cells.

The Th1 and Th2 preference induced by cells from the Peyer's patch (PP) and spleen (SPL) with various doses of an antigen was examined. The same splenic T cell receptor-transgenic CD4+ T cells were first incubated with PP or SPL cells in the presence of various doses of an antigen, and the cytokine response was observed after secondary stimulation. A Th2-type pattern was only obtained for primary stimulation at 10 microM of the antigen with PP cells, whereas a Th1 pattern was induced at both higher and lower concentrations. SPL cells in the presence of 0.1 to 1 microM of the antigen induced the secretion of Th2-type cytokines. Ten and 100 microM of the antigen plus SPL cells did not induce the release of a large quantity of cytokines. PP cells induced a different cytokine pattern at the antigen concentration that induced a similar level of T cell proliferation with SPL cells. Our findings suggest that the antigen-dose dependent development of Th1/Th2 cells is differentially modulated by the antigen-presentation function of cells in PP and SPL.