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Candidate biomarker identification for blood stasis syndrome among coronary artery disease patients using the Olink proteomics platform.

OBJECTIVE: To identify candidate biomarkers of blood stasis syndrome (BSS) associated with coronary artery disease (CAD) and explore the underlying inflammatory mechanisms. METHODS: Using the Olink Target 96 Inflammation panel, we identified plasma proteins in a group of 88 patients comprised of healthy controls (HCs), those with CAD and BSS (CAD-BSS), those with CAD without BSS (CAD-non-BSS), and those with BSS without CAD (non-CAD-BSS) (n = 22 in each group). Protein molecules that were specifically expressed in CAD or BSS were identified by differential expression analyses. Subsequently, potential protein biomarkers were identified using least absolute shrinkage and selection operator regression to enable CAD and BSS differentiation. The potential functional mechanisms of identified proteins were then determined by Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. RESULTS: Patients with CAD had 31/92 upregulated and 4/92 downregulated proteins compared with those without. Chemokine (C-C motif) ligand 11 (CCL11), CUB domain-containing protein 1, hepatocyte growth factor, sirtuin 2 (SIRT2), eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), CCL25, and tumor necrosis factor (TNF) showed the strongest upregulation (all P <0.0001). Patients with BSS had 8/92 downregulated proteins, specifically CCL28, CCL11, cystatin D, STAM-binding protein, 4E-BP1, matrix metalloproteinase-10, SIRT2, and monocyte chemotactic protein 4, compared with those without (all P < 0.05). The CAD-BSS group had one interleukin-17 (IL-17) upregulated and 10/92 downregulated proteins compared with the CAD-non-BSS group. When compared with the non-CAD-BSS group, the CAD-BSS group had 8 upregulated proteins but only 2 downregulated proteins, namely interleukin-10 receptor subunit alpha (IL-10RA) and TNF-related activation-induced cytokine (both P < 0.05). Totally 10 proteins were identified as potential candidate biomarkers of BSS in CAD patients. After least absolute shrinkage and selection operator regression analysis, two proteins that distinguished between BSS and non-BSS individuals among CAD patients were identified (SIRT2 and 4E-BP1). These proteins are primarily associated with the mechanistic target of rapamycin signaling pathway, which regulates inflammation and oxidative stress. CONCLUSIONS: Results suggest that the inflammatory response and mechanistic target of rapamycin signaling pathway participate in CAD and BSS development, and that SIRT2 and 4E-BP1 are prospective protein biomarkers for patients with CAD and BSS.

Humans↗

SHIP-1 Differentially Regulates IgE-Induced IL-10 and Antiviral Responses in Human Monocytes.

IgE-mediated stimulation of monocytes regulates multiple cellular functions including cellular maturation, cytokine release, antiviral responses, and T-cell differentiation. Expression of the high-affinity IgE receptor, Fc&#x3b5;RI, is closely linked to serum IgE levels and atopic disease. The signaling molecules regulating Fc&#x3b5;RI effector functions have been well studied in mast cells and basophils; however, less is known about the signaling and regulatory mechanisms in monocytes. This study sought to identify regulators of IgE-mediated cytokine release in human monocytes. SHIP-1 was identified as a negative regulator of IgE-induced IL-10 production. It was also determined that IgE-mediated stimulation and SHIP-1 inhibition decreased antiviral IP-10 production after liposomal poly(I:C) stimulation, indicating differential regulation by SHIP-1 in IgE-driven and antiviral response pathways. SHIP-1 and NF-&#x3ba;B were activated following IgE-mediated stimulation of monocytes, and NF-&#x3ba;B activation was related to both SHIP-1 and Fc&#x3b5;RI&#x3b1; cellular expression levels. To our knowledge, this is the first study to identify a role for SHIP-1 in regulating IgE-mediated and antiviral responses in human monocytes. Given the importance of monocytes in inflammation and immune responses, a better understanding of the signaling and regulatory mechanisms downstream of the Fc&#x3b5;RI receptor could lead to new therapeutic targets in allergic disease.

Humans↗

Defined human Clostridia consortia reverse colitis via dual effects of tryptophan metabolites on microbiota and immunity.

Microbial dysbiosis and disrupted mucosal immune homeostasis are integrally involved in the pathogenesis of inflammatory bowel diseases (IBDs). Live biotherapeutic products (LBPs) offer a potential therapeutic strategy to restore beneficial microbes and mitigate disease. We investigated the therapeutic efficacy of 2 LBPs, human Clostridia consortia 17-mix and 11-mix, by treating established colitis in murine models. Both LBPs exhibited therapeutic effects in T cell-mediated chronic colitis models induced by human microbiota and in pathobiont-driven gnotobiotic colitis models established with combinations of IBD-relevant human-derived strains. Metagenomic and metabolomic analyses elucidated mechanisms that go beyond established functions driven by short-chain fatty acids (SCFAs) and interleukin (IL)-10-producing regulatory T cells. Notably, LBPs exerted therapeutic effects by directly inhibiting resident pathobionts and through IL-10-independent activation of host anti-inflammatory aryl hydrocarbon receptor (AhR) pathways by bacterial tryptophan metabolites. These results elucidate SCFA- and IL-10-independent protective mechanisms exerted by defined resident bacterial strains that are depleted in IBD dysbiosis.

Animals↗

Genetic diversity of Collaborative Cross mice implicates FFAR3 as a target for ILC2 anti-inflammatory reprogramming.

Pulmonary group 2 innate lymphoid cells (ILC2s) are key drivers of Type 2 inflammation in diseases like asthma, yet the molecular mechanisms regulating their function are incompletely understood. Using the genetically diverse Collaborative Cross (CC) mouse panel, we mapped a quantitative trait locus (QTL) that governs ILC2 prevalence in the lung after aeroallergen exposure. This QTL induces a large population of ILC2s in the lung that are resistant to activation and have diminished Type 2 effector function. We identified free-fatty acid receptor 3 (Ffar3) as a gene responsible for this effect and demonstrated that FFAR3 signaling reprograms ILC2s to an anti-inflammatory state by promoting their survival, reducing Type 2 cytokine production, and enhancing IL-10 expression. This anti-inflammatory state is dependent on IL-2 signaling, is characterized by decreased ST2 expression, and is distinct from previously described IL-10-producing ILC2 phenotypes. FFAR3-dependent reprogramming is mediated by epidermal growth factor receptor (EGFR) upregulation, and FFAR3's anti-inflammatory effect is partially conserved in human ILC2s.

Animals↗

Localized PD-1 CAR T therapy reprograms neuroinflammation.

B cell-depleting therapies are effective in multiple sclerosis (MS), yet some patients relapse, underscoring the need for more precise interventions. To identify new therapeutic targets, we generated a single-cell RNA sequencing (scRNA-seq) atlas of cerebrospinal fluid (CSF), brain, and blood from non-inflammatory controls and patients with MS or other neuroinflammatory diseases. We found disease-associated enrichment of class-switched immunoglobulin G+ (IgG+) B cells and plasma cells in MS CSF. Unbiased analysis identified a rare disease-enriched subset of activated, T cell receptor (TCR)-restricted, PD-1+ T follicular helper-like cells with B cell-recruiting features. To target this population, we developed PD-1-directed chimeric antigen receptor (CAR) T cells that selectively depleted pathogenic PD-1+ CD4 T cells and locally released IL-10. This strategy attenuated central nervous system (CNS) inflammation, reprogrammed the local immune milieu, and improved clinical outcomes across murine neuroinflammation models. These findings define a CNS-localized adaptive immune circuit in MS and nominate programmable PD-1 CAR T cells as a strategy to disrupt it.

Animals↗

Levels of circulating kidney injury markers and IL-10 identify non-critically ill patients with COVID-19 at risk of death.

BACKGROUNDAfter identifying 2 immunomarkers of acute injury, KIM-1 and LCN2, in all kidney biopsies from 31 patients with COVID-19 pneumonia and de novo kidney dysfunction, we investigated whether circulating markers of kidney epithelial injury are common in patients with laboratory-confirmed COVID-19 who require oxygen support but do not have critical illness.METHODSWe studied 196 patients admitted to 15 hospitals with moderate to severe pneumonia who were enrolled in 2 independent randomized clinical trials. We measured 41 immune mediators and markers of kidney and endothelial injury in peripheral blood in these patients within 24 hours of randomization.RESULTSWe constructed a generalized linear CORIMUNO model combining serum levels of KIM-1, LCN2, IL-10, and age at hospital admission that showed high discrimination for mortality (derivation cohort: AUC = 0.82, 95% CI: 0.73-0.92; validation cohort: AUC = 0.83, 95% CI: 0.74-0.92). An early rise in circulating kidney injury markers, in the absence of acute kidney injury criteria, was markedly associated with the risk of developing a severe form of COVID-19 and death within 3 months.CONCLUSIONThe CORIMUNO score may be a helpful tool for risk stratification, and for the first time to our knowledge, it identifies the overlooked impact of subclinical kidney injury on pneumonia outcomes.TRIAL REGISTRATIONClinicalTrials.gov NCT04324047, NCT04324073, and NCT04331808.FUNDINGThis research was funded by the French Ministry of Health, Programme Hospitalier de Recherche Clinique (PHRC COVID-19-20-0151, PHRC COVID-19-20-0029), Fondation de l'Assistance Publique H&#xf4;pitaux de Paris (Alliance Tous Unis Contre le Virus), Assistance Publique H&#xf4;pitaux de Paris, and grants from the Fondation pour la Recherche M&#xe9;dicale (FRM) (REA202010012514) and Agence Nationale de Recherches sur le Sida and emerging infectious diseases (ANRS) (ANRS0147) from the VINTED sponsorship.

Humans↗

A transient, B cell-targeted tolerance switch using nanoparticles loaded with metabolizable AhR agonists for antigen-specific immune regulation.

Achieving antigen-specific immune tolerance without systemic immunosuppression remains a major challenge in biomaterial-based immunotherapy. Here, we report a simple nanoparticle (NP)-based platform that enables a transient, B cell-targeted tolerance switch. NPs encapsulating metabolizable aryl hydrocarbon receptor (AhR) agonists-FICZ or ITE-preferentially accumulate in splenic marginal zone B cells and convert them into IL-10-producing regulatory B cells (Bregs). This study provides the first in vivo evidence that Bregs can directly present antigen and induce regulatory T cells (Tregs), establishing a NP-controlled Breg-Treg pathway. These Bregs promote antigen-specific Tregs expansion only when co-exposed to antigen, establishing time-gated, antigen-restricted immune regulation. By exploiting the rapid metabolism of AhR agonists, this system provides precise temporal control of tolerance induction while preserving vaccine responses. In mouse models, co-administration of FICZ-containing NP with antigen suppressed anti-drug antibody formation and ameliorated allergic inflammation. This NP platform demonstrates a strategy for safe, antigen-specific immunomodulation and offers a clinically adaptable framework for allergy and biotherapeutic tolerance.

Animals↗

[Effects and mechanisms of Jiawei Yigong San on the Th17/Treg balance in food allergy].

Objective To explore the effects and mechanisms of Jiawei Yigong San (JWYGS) on the T helper type 17 (Th17)/regulatory T (Treg) cell balance in food allergy (FA). Methods Active components, action targets of JWYGS, and FA-related targets, were screened via network pharmacology. Overlapping targets between JWYGS and FA were used to construct a protein-protein interaction (PPI) network. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed to predict key signaling pathways. Molecular docking was conducted to validate the binding affinity between the main active components and the predicted targets. Mice were randomly divided into control group, model group, JWYGS low-dose, medium-dose, and high-dose groups, and dexamethasone (DXM) group. An ovalbumin (OVA)-induced FA model was established. During the OVA challenge period, mice received daily intragastric administration, after which allergy and diarrhea scores were assessed. Small intestinal pathology was evaluated by HE staining. Serum ovalbumin-specific immunoglobulin E (OVA-sIgE), interleukin 6 (IL-6), IL-17, IL-2, and IL-10 were measured by ELISA. Small intestinal IL-6, IL-17, and IL-10 protein expression was detected by immunohistochemistry. Splenic Th17 and Treg cells were quantified by flow cytometry, and the Th17/Treg ratio was calculated. The mRNA expression of IL-6, retinoic acid receptor-related orphan receptor &#x3b3;t (ROR&#x3b3;t), and forkhead box protein P3 (FOXP3) in the small intestine was detected by qPCR. Results Network pharmacology identified 235 active components of JWYGS and 136 common targets. GO and KEGG enrichment analyses highlighted cytokine response and Th17 differentiation. Molecular docking confirmed stable binding between core components and targets. Compared with the control group, the model group exhibited aggravated allergy and diarrhea scores, marked small intestinal inflammation and mucosal damage, elevated serum levels of OVA-sIgE, IL-6, IL-17 and IL-2, along with increased splenic Th17 cell frequency and Th17/Treg ratio. Intestinal IL-6 and IL-17 protein levels as well as IL-6 and ROR&#x3b3;t mRNA expression were upregulated, whereas serum IL-10 levels were decreased, and intestinal expression of IL-10 protein and FOXP3 mRNA was downregulated. After JWYGS treatment, allergy and diarrhea scores were significantly reduced. Small intestinal inflammation and mucosal damage were alleviated. Serum levels of OVA-sIgE, IL-17, IL-6 and IL-2, Th17 cell frequency and the Th17/Treg ratio, intestinal IL-6 and IL-17 protein levels were decreased. IL-6 and ROR&#x3b3;t mRNA expression was downregulated. Serum IL-10 levels were increased and intestinal expression of IL-10 protein and FOXP3 mRNA was upregulated. Moreover, the JWYGS high-dose group demonstrated comparable efficacy to the DXM group. Conclusion JWYGS can ameliorate symptoms and reverse the Th17/Treg imbalance in FA mice, potentially by inhibiting IL-6 transcription and regulating ROR&#x3b3;t/FOXP3 expression.

Animals↗

Natural killer (NK) cells with downregulated activating receptors and IL-10 production promote Trypanosoma cruzi T-cell responses in subjects in the Chronic phase of Trypanosoma cruzi infection: An exploratory immunological analysis.

BACKGROUND: Subjects with chronic Chagas disease and no signs of heart disease exhibit decreased NKp46 expression, high CD57 expression, and IL-10 production by NK cells. This study provides a detailed characterization of the phenotype and function of NK cells according to the severity of heart disease, and evaluates how these changes following treatment with benznidazole, as well as their association with Trypanosoma cruzi-specific T-cell responses. METHODS: The phenotype and function of NK cells in a cohort of 51 subjects infected with Trypanosoma cruzi and exhibiting varying degrees of heart disease were evaluated using high-dimensional flow cytometry and Boolean gating analysis. ELISPOT assays were performed to measure IFN-&#x3b3; and IL-2 production in response to T. cruzi antigens, using CD56, CD4 and CD8-depleted PBMC. RESULTS: In contrast to individuals without heart disease, those with advanced cardiomyopathy have an increased number of NK cells that express the activating receptors NKp46 and CD16, as well as the differentiation marker CD57. NK cells in subjects with advanced cardiomyopathy were also found to be enriched in CD56+CD107+granzyme B+TNF-&#x3b1;+ cells and depleted of CD56+IL-10+ cells. The function of NK cells shifted towards monofunctionality in subjects with declining T. cruzi-specific antibodies following treatment with benznidazole. Eliminating CD56+ cells significantly decreased the number of IFN-&#x3b3;-producing cells in response to T. cruzi. CONCLUSIONS: In chronic T. cruzi infection, NK-cell function may be balanced by the downregulation of activating receptors and IL-10 production, However, parasite persistence may desensitize the regulation of NK activating receptors, enabling NK cells to exert a potent polyfunctional cytotoxicity that potentially induce tissue damage.

Humans↗

Continuous anti-interleukin 10 antibody administration depletes mice of Ly-1 B cells but not conventional B cells.

Ly-1 B cells have the distinctive property of continuous self-replenishment and, as we have shown previously, can be further distinguished from conventional B cells on the basis of greatly elevated constitutive and inducible production of the recently described cytokine interleukin 10 (IL-10). To test the possibility that IL-10 acts as either an autocrine or paracrine growth factor for Ly-1 B cells, we treated mice continuously from birth to 8 wk of age with a monoclonal rat IgM antibody that specifically neutralizes mouse IL-10. Mice treated in this way lacked peritoneal-resident Ly-1 B cells, contained greatly reduced serum immunoglobulin M levels, and were unable to generate significant in vivo antibody responses to intraperitoneal injections of alpha 1,3-dextran or phosphorylcholine, antigens for which specific B cells reside in the Ly-1 B cell subset. In contrast, conventional splenic B cells of anti-IL-10-treated mice were normal with respect to total numbers, phenotype, and in vitro responsiveness to B cell mitogens and the thymus-dependent antigen trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH). The mechanism of Ly-1 B cell depletion appeared to be related to elevation of endogenous interferon gamma (IFN-gamma) levels in anti-IL-10-treated mice, since coadministration of neutralizing anti-IFN-gamma antibodies substantially restored the number of peritoneal-resident Ly-1 B cells in these mice. These results implicate IL-10 as a regulator of Ly-1 B cell development, and identify a procedure to specifically deplete Ly-1 B cells, thereby allowing further evaluation of the role of these cells in the immune system.

Animals↗

Selective expression of interleukin 10, interferon gamma, and granulocyte-macrophage colony-stimulating factor in ovarian cancer biopsies.

The variable clinical response seen with most cancer immunotherapy suggests that there is a large interindividual variation in immunologic response to tumors. One of the key functional parameters of an immune response is the local production of cytokines. As a method to survey the immune status of tumor-infiltrating cells, we have investigated the constitutive expression of cytokine mRNA in biopsies from epithelial ovarian carcinomas by using a PCR-assisted mRNA amplification assay. Using a set of cytokine-specific primers for 10 different cytokines, we have found selective expression of interleukin 10 (IL-10), granulocyte-macrophage colony-stimulating factor, and interferon gamma mRNA in ovarian tumor tissue as compared to normal ovaries and ovarian tumor cell lines. Such differences could not be explained by the extent of T-cell infiltration, since comparing samples with the same intensity of T-cell receptor (TCR) constant region alpha-chain product from the tumor and normal biopsies demonstrated different cytokine patterns. No IL-2 gene expression was detected in the tumor biopsies. IL-2 mRNA, however, became expressed after stimulation of the tumor-derived cells via the CD3 molecule but not after growth in recombinant IL-2 alone. Using the same methodology, we also analyzed the TCR variable region beta-chain gene repertoire. No restriction or biased expression of these genes was observed.

Base Sequence↗

Circulating inflammatory proteins and osteomyelitis: A bidirectional Mendelian randomization and colocalization analysis.

Circulating inflammatory proteins (CIPs) have been implicated in the progression of osteomyelitis (OM); however, whether these proteins play a causal role or are merely a consequence remains unclear. This study aimed to assess the causal relationships between CIPs and OM using a bidirectional 2-sample Mendelian randomization (MR) approach. MR analyses were performed using genome-wide association study summary statistics for 91 inflammation-related proteins (n&#x2005;=&#x2005;14,824) and OM (1881 cases and 3,91,037 controls). The inverse variance weighted method was used as the primary analytical approach, supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Sensitivity analyses were conducted to evaluate heterogeneity, horizontal pleiotropy, and robustness. Colocalization analysis was applied to identify shared causal variants, and pathway enrichment analysis was used to explore underlying biological mechanisms. Forward MR analysis revealed that elevated levels of tumor necrosis factor-beta (TNF-&#x3b2;) were significantly associated with increased OM risk (odds ratio [OR]&#x2005;=&#x2005;1.132; 95% confidence interval [CI]: 1.052-1.217; false discovery rate [FDR]&#x2005;=&#x2005;0.027). Conversely, decreased levels of osteoprotegerin (OR&#x2005;=&#x2005;0.772; 95% CI: 0.671-0.889; FDR&#x2005;=&#x2005;0.015) and adenosine deaminase (OR&#x2005;=&#x2005;0.811; 95% CI: 0.736-0.894; FDR&#x2005;<&#x2005;0.001) were associated with increased OM risk. Reverse MR analysis identified increased levels of interleukin-15 receptor alpha, C-X-C motif chemokine ligand 1, fms-related tyrosine kinase 3 ligand, interleukin-20, interleukin-10 (IL10), C-C motif chemokine ligand 19, and CXCL6 as being significantly associated with OM susceptibility (all FDR&#x2005;<&#x2005;0.05). Colocalization analysis provided strong evidence for a shared causal variant between TNF-&#x3b2; and OM (posterior probability for hypothesis 4&#x2005;=&#x2005;0.999). Enrichment analyses indicated involvement of implicated proteins in Toll-like receptor signaling and T-helper 17 cell differentiation pathways. This study identified several CIPs - including TNF-&#x3b2;, osteoprotegerin, and adenosine deaminase - as potentially causal in OM development. These findings highlight promising targets for future immunomodulatory therapies aimed at preventing or mitigating osteomyelitis.

Humans↗

Heart allografts in murine systems. The differential activation of Th2-like effector cells in peripheral tolerance.

Activated CD4+ Th2 cells release cytokines (IL-4,-10) that block activation & cytokine (IL-2/IFN-gamma) release by proinflammatory T (CD4+,CD8+) effector cells. To test the hypothesis that peripheral tolerance to alloantigen is linked to differential activation of CD4+ Th2 cells we measured cytokine transcripts in heart grafts (C57BL/10----C3H/HeJ) and spleens of mice rendered "tolerant" by donor-specific blood transfusion, anti-CD4 mAb pretreatment, and cyclosporine administration. The expression of IL-2/IFN-gamma transcripts was reduced greater than 90% in grafts from tolerant recipients. IL-4/IL-10 transcripts were generally enhanced and persisted in graft and recipient spleen. Accordingly adoptive transfer studies were performed to determine whether Th2-like effectors, which express Fc receptors (FcR), mediate suppression in this model. Unfractionated mononuclear cells (MC) (5 x 10(6), isolated from spleens of heart graft recipients made tolerant by DST, prolonged the survival of test grafts greater than 90 days in irradiated (680 rads) recipients reconstituted with a sufficient number of MC from spleens of naive C3H to precipitate rejection of the test graft in 18.2 days (MST, n = 5). Conversely adoptive transfer of inocula depleted of FcR+ cells on immune complex columns or with anti-FcR mAb 24G2 caused test grafts to be rejected in 8-11 days. These results suggest that peripheral tolerance to alloantigen may be linked to differential activation of Th2 cells that induce anergy by suppression. The possibility that Th2-like effectors mediate peripheral tolerance to self is discussed.

Animals↗

A protective NOD islet-infiltrating CD8+ T cell clone, I.S. 2.15, has in vitro immunosuppressive properties.

Type 1, insulin-dependent diabetes mellitus (IDDM) appears to result from a T cell-dependent destruction of insulin-producing pancreatic beta cells. In non-obese diabetic (NOD) mice and in other rodent models of human IDDM, final expression of disease may be controlled by protective, as well as, destructive T cell influences. Previously, a CD8+ T cell clone, I.S. 2.15, was isolated directly from islets of disease-resistant male NOD mice. Upon transfer to young NOD recipients, the non-cytolytic I.S. 21.5 T cell clone, confers in vivo protection from two forms of accelerated IDDM. The present study demonstrates that I.S. 2.15 T cells induce in vitro immunosuppression. The suppressive effects of I.S. 2.15 T cells are mediated through soluble factor(s) and are independent of T cell activation, cell contact, antigen specificity or the major histocompatibility complex (MHC). By polymerase chain reaction (PCR), I.S. 2.15 T cells contain mRNA species encoding for the potentially immunosuppressive cytokines, interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta). The T cell suppressive effects engendered by I.S. 2.15 T cells closely mimic those observed with TGF-beta. Moreover, I.S. 2.15-induced immunosuppression correlates with intracellular levels of TGF-beta mRNA. These results establish that immunoregulatory T cells are present within islets in IDDM-resistant NOD mice and may impact on final disease expression through the production of soluble mediator(s).

Animals↗

Differential regulation of T helper phenotype development by interleukins 4 and 10 in an alpha beta T-cell-receptor transgenic system.

To address the mechanisms controlling T helper (Th) phenotype development, we used DO10, a transgenic mouse line that expresses the alpha beta T-cell receptor from an ovalbumin-reactive T hybridoma, as a source of naive T cells that can be stimulated in vitro with ovalbumin peptide presented by defined antigen-presenting cells (APCs). We have examined the role of cytokines and APCs in the regulation of Th phenotype development. Interleukin 4 (IL-4) directs development toward the Th2 phenotype, stimulating IL-4 and silencing IL-2 and interferon gamma production in developing T cells. Splenic APCs direct development toward the Th1 phenotype when endogenous IL-10 is neutralized with anti-IL-10 antibody. The splenic APCs mediating these effects are probably macrophages or dendritic cells and not B cells, since IL-10 is incapable of affecting Th phenotype development when the B-cell hybridoma TA3 is used as the APC. These results suggest that early regulation of IL-4 and IL-10 in a developing immune response and the identity of the initiating APCs are critical in determining the Th phenotype of the developing T cells.

Animals↗

Interleukin 10 is a potent growth and differentiation factor for activated human B lymphocytes.

Interleukin 10 (IL-10), originally identified as a TH2 helper T-cell product able to inhibit cytokine production by TH1 cells, is highly homologous to BCRF1 (viral IL-10), an open reading frame in the Epstein-Barr virus genome. Here, we show that human and viral IL-10 stimulate DNA replication of B lymphocytes activated either via their antigen receptor or via their CD40 antigen. IL-4 and IL-10 display additive effects and induce a strong increase in the number of viable cells. Moreover, IL-10 induces activated B cells to secrete large amounts of IgG, IgA, and IgM, and the combination of IL-10 and IL-4 results in the secretion of the four immunoglobulin isotypes. Thus, IL-10 may play an important role in the amplification of humoral responses.

Antibody Formation↗

CD4+ Th2 response induced by Schistosoma mansoni eggs develops rapidly, through an early, transient, Th0-like stage.

Data from recent studies of murine schistosomiasis mansoni have indicated that certain characteristics of this infection, such as eosinophilia and elevated IgE, are due largely to the induction of Th2-like immune responses by parasite ova. The present study was designed to examine more closely the genesis and development of these skewed Th responses to schistosome eggs. Accordingly, eggs isolated from infected mice were injected s.c. into normal mice. After inoculation, draining lymph node (LN) cells were recovered, phenotyped, and tested for their ability to proliferate and secrete IL-2 and IFN-gamma (as markers of Th1 function) and IL-4, IL-5, and IL-10 (Th2 cytokines). The results show a maximal LN enlargement of 40- to 100-fold by day 3 after egg inoculation. The CD4/CD8/B cell ratio at this time is similar to that in LN from normal mice, but increases in numbers of cells expressing very low levels of MEL-14 and high levels of Pgp-1 are evident by days 3 and 10, respectively. Surprisingly, the initial detectable Ag-specific response to schistosome eggs, observed at day 1, is the production of IFN-gamma. By day 3, LN cells are capable of proliferating and making IFN-gamma plus IL-2, IL-4, IL-5, and IL-10 when stimulated with soluble egg Ag and, therefore, appear Th0-like. After 7 to 10 days, IFN-gamma production is severely depressed but the response continues to be characterized by IL-4, IL-5, IL-10, and IL-2. Depletion studies indicate that CD4 cells are the major population responsible for Ag-mediated proliferation and cytokine production. Results show that schistosome eggs are autonomous inducers of vigorous Th2-like effector responses. Further, our data, from a system that utilizes an in vivo priming step, support the contentions that skewed Th responses develop via an intermediate Th0 stage is accompanied by a loss of the MEL-14 surface marker and an increase in Pgp-1 expression.

Animals↗

Schistosoma mansoni eggs induce antigen-responsive CD44-hi T helper 2 cells and IL-4-secreting CD44-lo cells. Potential for T helper 2 subset differentiation is evident at the precursor level.

Schistosoma mansoni eggs are potent inducers of biased Th2-like immune responses. Using a model system where mice are immunized with isolated schistosome eggs, we demonstrate that CD44 expression, up-regulation of which has been linked to Th cell development, is increased on Th2 cells. We also investigate the functional properties of CD44-lo Th cells recovered from the overtly Th2 environment constituted by lymph nodes draining sites of egg deposition. Production of high levels of IL-4, IL-5, and IL-10 by Th cells responding to egg Ag is shown to be the property of a subpopulation expressing CD44-hi. This population of Th cells cosegregates with a blasting subpopulation expressing more IL-4R (but similar amounts of IL-2R) than Th cells from normal mice. These results indicate that mature Th2 cells responding to schistosome eggs are CD44-hi and suggest that they use IL-4 as a growth factor. In contrast, CD44-lo cells sorted from lymph node populations responding to eggs are able to produce small amounts of IL-4 and IL-2, but no IL-5 or IL-10. This is surprising, because low expression of CD44 is considered a characteristic of Th cell naivite and concomitant ability to produce only IL-2. Thus, in lymph nodes responding to schistosome eggs, potential for Th2 subset differentiation is evident within the CD44-lo precursor Th subpopulation.

Animals↗