Measles virus infection in adults induces production of IL-10 and is associated with increased CD4+ CD25+ regulatory T cells

Despite steady progress in elimination of measles virus globally, measles infection still causes 500,000 annual deaths, mostly in developing countries where endemic measles strains still circulate. Many adults are infected every year in China, with symptoms more severe than those observed in children. In this study, we have used blood samples from adult measles patients in Shanghai and age-matched healthy controls to gain an understanding of the immune status of adult measles patients. IFN-alpha mRNA was reduced in patient PBMC compared with healthy controls. In contrast, gene expression and plasma production of IL-2, IL-10, and IFN-gamma were elevated in patient blood. A similar cytokine profile was observed at early times when cultured PBMC were infected with a clinical isolate of measles virus. In contrast to previous studies in pediatric patients, we did not find a reduction in total CD4(+) and CD8(+) T cells in patient PBMC. Interestingly, we found that CD4(+)CD25(+)CD127(low) regulatory T cells were significantly increased in patient PBMC compared with controls. Using intracellular cytokine staining we also show that the measles virus induces IL-10-producing CD14(+) and CD4(+)CD25(+) cells in PBMC. Our results show that adult measles patients in the acute phase of the disease have a mixed Th1/Th2 type response, accompanied with severe immunosuppression of both innate and adaptive responses including suppression of type I IFN. Both regulatory T cells and plasma IL-10 may contribute to the immunosuppression.     

Cellular basis of the role of diesel exhaust particles in inducing Th2-dominant response

There is growing evidence that diesel exhaust particles (DEP) can induce allergic diseases with increased IgE production and preferential activation of Th2 cells. To clarify the cellular basis of the role of DEP in the induction of Th2-dominant responses, we examined the effects of DEP on the cytokine production by T cells stimulated with anti-CD3/CD28 Ab and on that by monocyte-derived dendritic cells (MoDCs) stimulated with CD40L and/or IFN-gamma. We examined IFN-gamma, IL-4, IL-5, IL-8, and IL-10 produced by T cells and TNF-alpha, IL-1beta, IL-10, and IL-12 produced by MoDCs using real-time PCR analysis or by ELISA. To highlight the effects of DEP, we compared the effects of DEP with those of dexamethasone (DEX) and cyclosporin A (CyA). DEP significantly suppressed IFN-gamma mRNA expression and protein production, while it did not affect IL-4 or IL-5 mRNA expression or protein production. The suppressive effect on IFN-gamma mRNA expression was more potent than that of DEX and comparable at 30 mug/ml with 10(-7) M CyA. The suppressive effect on IFN-gamma production was also more potent than that of either DEX or CyA. DEP suppressed IL-12p40 and IL-12p35 mRNA expression and IL-12p40 and IL-12p70 production by MoDCs, while it augmented IL-1beta mRNA expression. Finally, by using a thiol antioxidant, N-acetyl cysteine, we found that the suppression of IFN-gamma production by DEP-treated T cells was mediated by oxidative stress. These data revealed a unique characteristic of DEP, namely that they induce a Th2 cytokine milieu in both T cells and dendritic cells.     

Semiquantitative analysis of Th1 and Th2 cytokine expression in CD3+, CD4+, and CD8+renal-cell-carcinoma-infiltrating lymphocytes

The mRNA expression of Th1 and Th2 cytokines was compared in freshly isolated CD3⁺ tumor-infiltrating lymphocytes (CD3⁺ TIL) and in autologous CD3⁺ peripheral blood lymphocytes (CD3⁺ PBL) obtained simultaneously from 20 patients with renal cell carcinomas (RCC). In addition cytokine expression was compared in CD4⁺ TIL and CD8⁺ TIL from another group of 20 patients with RCC. TIL were isolated from mechanically disaggregated tumor material and PBL from peripheral blood by gradient centrifugation and subsequent selection with anti-CD3, anti-CD4 or anti-CD8 magnetic beads. In these pure lymphocyte preparations the constitutive expression of interleukin-1 (IL-1), IL-2, IL-10, interferon γ (IFN), and tumor necrosis factor α (TNF) was determined by using a polymerase-chain-reaction-assisted mRNA amplification assay. In the CD3⁺ TIL, levels of mRNA for IFN, IL-10, IL-1 and TNF were significantly higher than in the autologous CD3⁺ PBL whereas IL-2 expression was rather low and did not differ in the two populations. Comparison of cytokine mRNA expression in CD4⁺ TIL and simultaneously obtained CD8⁺ TIL revealed a significantly higher expression of IFN in the CD8⁺ cells. These data reflect an in vivo activation of RCC-infiltrating lymphocytes at the mRNA level with respect to the Th1 as well as the Th2 immune response. Th1 activation seems to be most evident in the CD8⁺ TIL. Received: 14 January 1999 / Accepted: 30 April 1999     

DNA vaccines: influenza virus challenge of a Th2/Tc2 immune response results in a Th2/Tc1 response in the lung

For this study, we used DNA-based immunizations to elicit gamma interferon-producing (Tc1) or interleukin 4 (IL-4)-producing (Tc2) CD8 T cells to the influenza virus nucleoprotein. We examined the response of these cells to an intranasal viral challenge. Both the Tc2- and Tc1-biased responses were present in mice with predominantly IL-4-producing (Th2) CD4 T cells. After viral challenge, Tc1 cells underwent more efficient expansion than did Tc2 cells, and only Tc1 cells were detected at the site of infection. In contrast, the CD4 response remained IL-4 biased. However, only a limited number of CD4 cells appeared in the postchallenge lung, and these were strongly enriched for the Th1 phenotype. Thus, the type of memory T-cell response induced by DNA vaccination does not determine the type of response that will predominate at the site of an infection.     

Th17 cells expressing KIR3DL2+ and responsive to HLA-B27 homodimers are increased in ankylosing spondylitis

CD4 Th cells producing the proinflammatory cytokine IL-17 (Th17) have been implicated in a number of inflammatory arthritides including the spondyloarthritides. Th17 development is promoted by IL-23. Ankylosing spondylitis, the most common spondyloarthritis (SpA), is genetically associated with both HLA-B27 (B27) and IL-23R polymorphisms; however, the link remains unexplained. We have previously shown that B27 can form H chain dimers (termed B27(2)), which, unlike classical HLA-B27, bind the killer-cell Ig-like receptor KIR3DL2. In this article, we show that B27(2)-expressing APCs stimulate the survival, proliferation, and IL-17 production of KIR3DL2(+) CD4 T cells. KIR3DL2(+) CD4 T cells are expanded and enriched for IL-17 production in the blood and synovial fluid of patients with SpA. Despite KIR3DL2(+) cells comprising a mean of just 15% of CD4 T in the peripheral blood of SpA patients, this subset accounted for 70% of the observed increase in Th17 numbers in SpA patients compared with control subjects. TCR-stimulated peripheral blood KIR3DL2(+) CD4 T cell lines from SpA patients secreted 4-fold more IL-17 than KIR3DL2(+) lines from controls or KIR3DL2(-) CD4 T cells. Strikingly, KIR3DL2(+) CD4 T cells account for the majority of peripheral blood CD4 T cell IL-23R expression and produce more IL-17 in the presence of IL-23. Our findings link HLA-B27 with IL-17 production and suggest new therapeutic strategies in ankylosing spondylitis/SpA.     

The Characteristics of Th1/Th2 Cytokine Receptors on Monocytes in Untreated Patients of Long Term Nonprogressor or Chronic HIV Infection

Monocytes/macrophages play crucial roles in immunity to microorganisms and are one of the important targets for human immunodeficiency virus (HIV) infection. The phenotypes and function of monocytes in HIV-infected patients were poorly determined. We herein detected the expression of Th1/Th2 cytokine receptors on monocyte subsets in the untreated HIV-infected patients of either long term nonprogressor (LTNP) or chronic infection (CHI). CD14+CD16- monocytes were significantly increased and CD14+CD16+ monocytes were reduced in patients of LTNP or CHI compared with healthy control. IL-6R expression on CD14+CD16- monocytes were decreased in patients of LTNP or CHI, whereas IL-4R and IL-10R expression on both CD14+CD16- and CD14+CD16+ monocyte subsets were increased in patients with LTNP or CHI, as determined by flow cytometry and real time PCR assays. The decreased IL-6R expression and enhanced IL-4R and IL-10R expression were also observed on CD4+ T cells of these patients, indicating that these changes in monocytes are not cell-specific. CD14+CD16- monocytes of HIV-infected patients produced less TNF-α and IL-1β but identical levels of IL-6, and IL-12 as the control after IFN-γ/LPS stimulation. However, in the presence of IL-4 or IL10, CD14+CD16- monocytes of HIV-infected patients produced more TNF-α, IL-6, IL-12 or Il-1β after IFN-γ/LPS stimulation than the healthy control, supporting the impaired IL-4R and IL-10R signal pathways in patients with LTNP and CHI. Therefore, our present study offered the basic information for the Th1/Th2 cytokine receptor expression and function on monocyte subsets in untreated HIV-infected individuals.     

Th17 and Th22 cells in psoriatic arthritis and psoriasis

Introduction

The aim of this study was to characterize interleukin 17 (IL-17) and interleukin 22 (IL-22) producing cells in peripheral blood (PB), skin, synovial fluid (SF) and synovial tissue (ST) in patients with psoriasis (Ps) and psoriatic arthritis (PsA).

Methods

Flow cytometry was used to enumerate cells making IL-22 and IL-17, in skin and/or SF and PB from 11 patients with Ps and 12 patients with PsA; skin and PB of 15 healthy controls and SF from rheumatoid arthritis (RA) patients were used as controls. Expression of the interleukin 23 receptor (IL-23R) and chemokine receptors CCR4 and CCR6 was examined. Secretion of IL-17 and IL-22 was measured by ELISA. ST was analysed by immunohistochemical staining of IL-17 and IL-22.

Results

Increased frequencies of IL-17+ and IL-22+ CD4+ T cells were seen in PB of patients with PsA and Ps. IL-17 secretion was significantly elevated in both PsA and Ps, whilst IL-22 secretion was higher in PsA compared to Ps and healthy controls. A higher proportion of the CD4+ cells making IL-17 or IL-22 expressed IL-23R and frequencies of IL-17+, CCR6+ and CCR4+ T cells were elevated in patients with Ps and those with PsA. In patients with PsA, CCR6+ and IL-23R + T cells numbers were elevated in SF compared to PB. Increased frequencies of IL-17+ and IL-22+ CD4+ T cells were demonstrated in Ps skin lesions. In contrast, whilst elevated frequencies of CD4+ IL-17+ cells were seen in PsA SF compared to PB, frequencies of CD4+ IL-22+ T cells were lower. Whereas IL-17 expression was equivalent in PsA, osteoarthritis (OA) and RA ST, IL-22 expression was higher in RA than either OA or PsA ST, in which IL-22 was strikingly absent.

Conclusions

Elevated frequencies of IL-17 and IL-22 producing CD4+ T cells were a feature of both Ps and PsA. However their differing distribution at disease sites, including lower frequencies of IL-22+ CD4+ T cells in SF compared to skin and PB, and lack of IL-22 expression in ST suggests that Th17 and Th22 cells have common, as well as divergent roles in the pathogenesis of Ps and PsA.     

Interleukin-4 therapy of psoriasis induces Th2 responses and improves human autoimmune disease

Selective skewing of autoreactive interferon-gamma (IFN-gamma)-producing T helper cells (Th1) toward an interleukin-4 (IL-4)-producing (Th2) phenotype can in experimental animals alleviate autoimmune disease without inducing general immunosuppression. In a prospective dose escalation study, we assessed treatment with human IL-4 (rhuIL-4) in 20 patients with severe psoriasis. The therapy was well tolerated, and within six weeks all patients showed decreased clinical scores and 15 improved more than 68%. Stable reduction of clinical scores was significantly better at 0.2-0.5 microg rhuIL-4 than at < or =0.1 microg rhuIL-4 (P = 0.009). In psoriatic lesions, treatment with 0.2-0.5 microg/kg rhuIL-4 reduced the concentrations of IL-8 and IL-19, two cytokines directly involved in psoriasis; the number of chemokine receptor CCR5+ Th1 cells; and the IFN-gamma/IL-4 ratio. In the circulation, 0.2-0.5 microg/kg rhuIL-4 increased the number of IL-4+CD4+ T cells two- to three-fold. Thus, IL-4 therapy can induce Th2 differentiation in human CD4+ T cells and has promise as a potential treatment for psoriasis, a prototypic Th1-associated autoimmune disease.     

Comparison of Th1 and Th2 responses in non-healing and healing patients with cutaneous leishmaniasis

Background:

Cutaneous leishmaniasis is an endemic disease in many regions of Iran, including the city of Mashhad. In recent years, some cases have not responded to Glucantime, the usual treatment for this disease. The cellular immune response caused by T-helper type 1 (Th1) cells has an important role in protection against leishmaniasis, and activation of the T-helper type 2 (Th2) response causes progression of the disease. By analyzing these responses we hope to find a more effective treatment than that currently in use for leishmaniasis patients.

Methods:

The cellular immune responses in 60 cases of non-healing and healing cutaneous leishmaniasis, and individuals in a control group, were analyzed by measuring cytokines released by peripheral blood mononuclear cells (PBMCs) when stimulated with Leishmania major antigens by Enzyme Linked Immuno Sorbent Assay (ELISA).

Results:

Subjects from the healing group secreted more interleukin-12 (IL-12) and interferon gamma (IFN-γ) (p<0.05) and less interleukins -4, -5, -10 (IL-4, IL-5, and IL-10) (p<0.005) and -18 (IL-18) (p=0.003) than the non-healing group.

Conclusions:

The results demonstrate that secretion of cytokines that activate Th2 response including IL-4, IL-5 and IL-10 in non-healing subjects was higher than healing subjects and secretion of cytokines that activate Th1 response including IL-12 and IFN-γ in healing subjects was higher relative to the non-healing subjects. In this study it has been shown that the level of IL-18 progresses disease in non-healing patients when the level of IL-12 gets decreased. Key Words: Cytokines, Cutaneous leishmaniasis, Glucantime     

Atrial natriuretic peptide polarizes human dendritic cells toward a Th2-promoting phenotype through its receptor guanylyl cyclase-coupled receptor A

Atrial natriuretic peptide (ANP) is a cardiovascular hormone secreted mainly by the cardiac atria and regulates the volume-pressure homeostasis. The action of ANP is mediated by its receptor, guanylyl cyclase-coupled receptor A (GC-A). In this study, we explored the possibility that ANP and GC-A may play a role in the dendritic cell (DC)-mediated immune regulation. We first examined the expression of GC-A in human monocyte-derived DCs in comparison with monocytes and found that DCs but not monocytes express GC-A at both the mRNA and protein levels. DCs responded to ANP with an increase in intracellular cGMP in a dose-dependent manner, indicating that GC-A expressed on DCs is functional. Furthermore, treatment of DCs with ANP decreased production of IL-12 and TNF-alpha and conversely increased that of IL-10 upon stimulation with LPS. In accordance with this change of cytokine production, DCs treated with ANP plus LPS promoted differentiation of naive CD4(+) T cells into a Th2 phenotype. Finally, we presented evidence that ANP affected cytokine production of fresh whole blood stimulated with LPS in line with the above-mentioned results. These results indicate that ANP polarizes human DCs toward a Th2-promoting phenotype through GC-A and thus can regulate immune responses.     

Th1型和Th2型细胞因子在口腔扁平苔藓患者外周血中的表达及临床意义

目的:研究口腔扁平苔藓(OLP1)患者Th1型和Th2型细胞因子的表达及临床意义。方法:选取2013年1月至2014年3月于我院就诊的21例充血糜烂型及14例光滑型OLP患者为研究对象,18例正常人为对照组,采用密度梯度离心法对各组外周血单个核细胞进行分离,酶联免疫吸附剂测定(ELISA)法对各组外周血单个核细胞中的IL-4和IFN-gamma的表达进行检测,逆转录-聚合酶链反应法对各组血清中IL-4 m RNA和IFN-gamma m RNA的表达进行检测。结果:与正常对照组相比,OLP患者IL-4m RNA及蛋白的表达均增高,而IFN-gamma m RNA及蛋白的表达则降低,差异均有显著统计学意义(均P0.01)。充血糜烂型及光滑型OLP患者组间比较发现,IL-4 m RNA和IFN-gamma m RNA及蛋白的表达差异无统计学意义(P0.05)。结论:OLP发病机制与Th1与Th2的表达失衡有关,为临床治疗提供参考。     

Cyclosporin A inhibits the production of IL-17 by memory Th17 cells from healthy individuals and patients with rheumatoid arthritis

Recent evidence from several studies indicated that IL-17-producing Th17 cells can represent the key effector cells in the induction and development of autoimmune disorders. Cyclosporine A (CsA) is a commonly used immunosuppressant to treat lots of autoimmune diseases including rheumatoid arthritis (RA). Here, we demonstrated that PBMCs and purified CD4⁺ T cells from healthy individuals and patients with RA could be induced to produce large amounts of IL-17 after stimulation with anti-CD3 plus anti-CD28 mAbs. Phenotypic analysis indicated that the majority of IL-17-producing cells were Th17 cells with memory phenotype. The addition of CsA into cell cultures significantly inhibited the IL-17 production by Th17 cells at protein and at mRNA levels. Compared to the PBMCs from normal individuals, PBMCs from the patients with RA produced higher levels of IL-17 that was also significantly inhibited by CsA both at protein and at mRNA levels. The mechanism might be the effect of CsA on the T cells activation because the expression of CD69 and CD25 molecules on T cells was markedly reduced in the presence of CsA. Taken together, these results demonstrated that CsA suppressed the IL-17 production and inhibited the Th17 cells differentiation from both healthy individuals and patients with RA.     

IL-9 enhances the growth of human mast cell progenitors under stimulation with stem cell factor

We examined the effects of IL-9 on human mast cell development from CD34(+) cord blood (CB) and peripheral blood cells in serum-deprived cultures. IL-9 apparently enhanced cell production under stimulation with stem cell factor (SCF) from CD34(+) CB cells. A great majority of the cultured cells grown with SCF + IL-9 became positive for tryptase at 4 wk. In methylcellulose cultures of CD34(+) CB cells, IL-9 increased both the number and size of mast cell colonies grown with SCF. Furthermore, SCF + IL-9 caused an exclusive expansion of mast cell colony-forming cells in a 2-wk liquid culture of CD34(+) CB cells, at a level markedly greater than for SCF alone. Clonal cell cultures and RT-PCR analysis showed that the targets of SCF + IL-9 were the CD34(+)CD38(+) CB cells rather than the CD34(+)CD38(-) CB cells. IL-9 neither augmented the SCF-dependent generation of progeny nor supported the survival of 6-wk-cultured mast cells. Moreover, there was no difference in the appearance of tryptase(+) cells and histamine content in the cultured cells between SCF and SCF + IL-9. The addition of IL-9 increased numbers of mast cell colonies grown with SCF from CD34(+) peripheral blood cells in children with or without asthma. It is of interest that mast cell progenitors of asthmatic patients responded to SCF + IL-9 to a greater extent than those of normal controls. Taken together, IL-9 appears to act as a potent enhancer for the SCF-dependent growth of mast cell progenitors in humans, particularly asthmatic patients.     

The pulmonary environment promotes Th2 cell responses after nasal-pulmonary immunization with antigen alone, but Th1 responses are induced during instances of intense immune stimulation

The purpose of this study was to determine the nature of the CD4(+) Th cell responses induced after nasal-pulmonary immunization, especially those coinciding with previously described pulmonary inflammation associated with the use of the mucosal adjuvant, cholera toxin (CT). The major T cell population in the lungs of naive mice was CD4(+), and these cells were shown to be predominantly of Th2 type as in vitro polyclonal stimulation resulted in IL-4, but not IFN-gamma, production. After nasal immunization with influenza Ag alone, Th2 cytokine mRNA (IL-4 and IL-5) levels were increased, whereas there was no change in Th1 cytokine (IL-2 and IFN-gamma) mRNA expression. The use of the mucosal adjuvant, CT, markedly enhanced pulmonary Th2-type responses; however, there was also a Th1 component to the T cell response. Using in vitro Ag stimulation of pulmonary lymphocytes, influenza virus-specific cytokine production correlated with the mRNA cytokine results. Furthermore, there was a large increase in CD4(+) Th cell numbers in lungs after nasal immunization using CT, correlating with the pulmonary inflammatory infiltrate previously described. Coincidentally, both macrophage-inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta mRNA expression increased in the lungs after immunization with Ag plus CT, while only MIP-1beta expression increased when mice were given influenza Ag alone. Our study suggests a mechanism to foster Th1 cell recruitment into the lung, which may impact on pulmonary immune responses. Thus, while Th2 cell responses may be prevalent in modulating mucosal immunity in the lungs, Th1 cell responses contribute to pulmonary defenses during instances of intense immune stimulation.     

Viral IL-10-induced immunosuppression requires Th2 cytokines and impairs APC function within the allograft

Previous reports demonstrated that retroviral mediated gene transfer of viral IL-10 (vIL-10) prolongs allograft survival by decreasing donor-specific cytotoxic T lymphocyte precursor (CTLp) and IL-2-secreting helper T lymphocyte precursor (HTLp) frequency within graft-infiltrating cells (GIC). This report now shows that vIL-10 efficacy is dependent on CD4(+) T cells, suggesting that immunosuppression may involve a switch from a Th1 to a Th2 alloresponse. In support of this, anti-IL-4 or anti-murine IL-10 (anti-mIL-10) mAbs, but not anti-IFN-gamma mAb, administered at the time of vIL-10 gene transfer prevents enhanced graft survival. Because Th switching involves APC function, GIC were examined for their ability to present alloantigen. GIC from vIL-10-treated grafts were shown to be mostly of recipient (CBA) origin, yet were unable to elicit alloproliferative responses from donor type (C57BL/6) or third party (BALB/c) responders. The inability of vIL-10-treated GIC to stimulate the MLR was not due to the generation of negative regulatory cells or the production of immunosuppressive cytokines such as IL-4, mIL-10, or TGFbeta. Using fractionated GIC subpopulations, the number of recipient type cells in the allografts was modestly reduced by vIL-10 gene transfer, while maintaining both APC phenotype and alloantigen presenting function. Conversely, after vIL-10 gene transfer, donor type GIC were unable to participate in direct alloantigen presentation. Therefore, local immunosuppression induced by vIL-10 gene transfer is CD4 T cell and IL-4 and mIL-10 dependent, and impairs direct alloantigen presentation through an alteration of donor type APC function.     

Expansion of Pathogen-Specific Mono- and Multifunctional Th1 and Th17 Cells in Multi-Focal Tuberculous Lymphadenitis

Background

Th1 and Th17 responses are known to play an important role in immunity to pulmonary tuberculosis (PTB), although little is known about their role in extrapulmonary forms of tuberculosis (TB).

Methods

To identify the role of Th1, Th17, and Th22 cells in multi-focal TB lymphadenitis (TBL), we examined mycobacteria–specific immune responses in the whole blood of individuals with PTB (n = 20) and compared them with those with TBL (n = 25).

Results

Elevated frequencies of CD4⁺ T cells expressing IFN- γ, TNF-α, and IL-2 were present in individuals with TBL compared with those with PTB at baseline and in response to ESAT-6 and CFP-10. Similarly, increased frequencies of CD4⁺ T cells expressing IL-17A, IL-17F, and IFN-γ were also present in individuals with TBL at baseline and following ESAT-6 and CFP-10 stimulation although no significant difference in frequency of Th22 cells was observed. Finally, frequencies of Th1 (but not Th17) cells exhibited a significantly negative correlation with natural regulatory T cell frequencies at baseline.

Conclusions

Multi-focal TB lymphadenitis is therefore characterized by elevated frequencies of Th1 and Th17 cells, indicating that Th1 and Th17 responses in TB disease are probably correlates of disease severity rather than of protective immunity.     

Th2-type immune response observed in healthy individuals to sonicate antigen prepared from the most prevalent Mycobacterium tuberculosis strain with single copy of IS6110

Different Mycobacterium tuberculosis strains operate different immune evasion strategies for their survival in the host. This mainly depends on the virulence of the strain and the host immune responses. The most virulent strains are actively involved in the transmission, widely spread in the community and induce differential immune responses. We evaluated the immune response of a sonicate antigen prepared from one predominant strain (S7) from M. tuberculosis harbouring a single copy of IS6110. Significant lymphoproliferative response against purified protein derivative from tubercle bacillus (PPD) and H37Rv antigens was observed in PPD positive normal individuals and tuberculosis patients. Interferon-gamma (IFN-gamma) levels against these antigens were significantly increased in normal individuals but not in tuberculosis patients. The antigen S7 showed marginal T-cell proliferation but did not induce IFN-gamma secretion in both groups. Conversely, it induced significantly high levels of cytokine interleukin 4 (IL-4) in normal individuals. The macrophage cytokines, IL-12 and tumour necrosis factor alpha (TNF-alpha), did not show S7 antigen specific stimulation. The intracellular cytokine further confirmed an increase in IL-4(+)/CD4+ T-cells and a decrease in IFN-gamma(+)/CD4+ T-cells upon stimulation. The antibody response showed an increase in IgG and IgA levels against this antigen in normal individuals. These observations suggest that antigen S7 modulates the immune response towards T helper cell type 2 by suppressing T helper cell type 1 protective immune response in PPD positive normal individuals. We speculate that some components of this sonicate antigen are associated with immunosuppressive response.