CD4 Th Cells Research Articles

Effect of curcumine in regulating the balance between regulatory T cells/helper T lymphocyte 17 via SOCS3 in inflammatory bowel disease in immature rat

Objective To determine the therapeutic efficacy of curcumine on inflammatory bowel disease (IBD) and its underlying mechanisms. Methods The rat ulcerative colitis model was developed by using 30 g/L dextran sulfate sodium.Twenty-four young rats were divided into 4 groups: normal group, model group, curcumin 100 mg/kg group(curcumin 100 group), and curcumin 300 mg/kg group(curcumin 300 group). Curcumin was given through gastric gavage once a day for 7 days.General condition, disease activity index (DAI) and histopathological score(HPS) were evaluated.The proportions of CD4+ CD25+Foxp3+ regulatory T cells(Treg) and CD4+ IL-17+ helper T lymphocyte 17(Th17) in CD4+ T cells in rats, and spleen cells were calculated by using flow cytometry.Immunohistochemical method was performed to determine the level of SOCS3 in colon tissues. Results After curcumin administered through gastric gavage for 5 days, compared with the DAI in the model group[(7.50±0.32) scores], HPS in the curcumin 100 group[(4.00±1.10) scores] and the curcumin 300 group [(5.00±0.89) scores] significantly reduced, and the difference was significant(F=12.469, P 0.05). Compared with the model group[(6.5±1.5)%], the propotion of CD4+ CD25+Foxp3+ Treg cells in CD4+ T cells in the curcumin 100 group[(9.9±1.0)%], the curcumin 300 group [(9.3±0.7)%] and the normal group[(9.6±1.1)%]was obviously upregulated(F=16.635, P 0.05). Compared with the model group[(3.5±1.4)%], the propotion of CD4+ IL-17+ Th17 cells in CD4+ T cells in the curcumin 100 group[(2.0±0.9)%], the curcumin 300 group [(1.2±0.6)%] and the normal group[(2.0±0.9)% ] was downregulated(F=5.155, P 0.05). There was no obvious difference between the curcumin 100 group and the curcumin 300 group in these indicators respectively(all P>0.05). Conclusions Curcumin probably attenuates IBD severity, reduces inflammation and regulates the balance of Treg/Th17 through the inhibition of SOCS3 expression. Key words: Inflammatory bowel disease; Curcumine; SOCS3; Regulatory T cells; Helper T lymphocyte 17

The IL15 +96522 A>T functional polymorphism is related to the differentiation of Th17 cells and the severity of Hashimoto's disease.

To clarify the association between the genetic producibility of IL-15, a pro-inflammatory cytokine, and the pathogenesis of autoimmune thyroid diseases (AITDs), we genotyped +96522 A>T and +82889 A>G polymorphisms in the IL15 gene using 127 patients with Hashimoto's disease (HD), including 55 patients with severe HD and 48 patients with mild HD; 130 patients with Graves' disease (GD), including 52 patients with intractable GD and 44 patients with GD in remission; and 79 healthy volunteers. Both the IL15 +96522 A allele and AA genotype were more frequent in patients with severe HD than in those with mild HD. The serum levels of IL-15 were higher in individuals with the IL15 +96522 AA genotype than in those with the T allele, and they were also higher in patients with severe HD than in those with mild HD. On the other hand, the mRNA levels of IL-15 were not significantly different among individuals with each genotype of both SNPs. After incubation with recombinant human IL-15, the proportions of Th17 cells in CD4+ cells were increased, and those of Treg cells in CD4+ cells were maintained. Our study indicates that the IL15 +96522A/C polymorphism correlates with the severity of HD, most likely by increasing Th17 cells.

CD8 T cell-mediated killing of orexinergic neurons induces a narcolepsy-like phenotype in mice

Narcolepsy with cataplexy is a rare and severe sleep disorder caused by the destruction of orexinergic neurons in the lateral hypothalamus. The genetic and environmental factors associated with narcolepsy, together with serologic data, collectively point to an autoimmune origin. The current animal models of narcolepsy, based on either disruption of the orexinergic neurotransmission or neurons, do not allow study of the potential autoimmune etiology. Here, we sought to generate a mouse model that allows deciphering of the immune mechanisms leading to orexin(+) neuron loss and narcolepsy development. We generated mice expressing the hemagglutinin (HA) as a "neo-self-antigen" specifically in hypothalamic orexin(+) neurons (called Orex-HA), which were transferred with effector neo-self-antigen-specific T cells to assess whether an autoimmune process could be at play in narcolepsy. Given the tight association of narcolepsy with the human leukocyte antigen (HLA) HLA-DQB1*06:02 allele, we first tested the pathogenic contribution of CD4 Th1 cells. Although these T cells readily infiltrated the hypothalamus and triggered local inflammation, they did not elicit the loss of orexin(+) neurons or clinical manifestations of narcolepsy. In contrast, the transfer of cytotoxic CD8 T cells (CTLs) led to both T-cell infiltration and specific destruction of orexin(+) neurons. This phenotype was further aggravated upon repeated injections of CTLs. In situ, CTLs interacted directly with MHC class I-expressing orexin(+) neurons, resulting in cytolytic granule polarization toward neurons. Finally, drastic neuronal loss caused manifestations mimicking human narcolepsy, such as cataplexy and sleep attacks. This work demonstrates the potential role of CTLs as final effectors of the immunopathological process in narcolepsy.

Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection

Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 Tcell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 Tcell polyfunctionality, enhanced antiviral CD8 Tcell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 Tcell demise during viral persistence with important implications for restoring antiviral CD8 Tcell immunity to control persistent viral infection.

Bifidobacterium animalis ssp. lactis CNCM-I2494 Restores Gut Barrier Permeability in Chronically Low-Grade Inflamed Mice.

Growing evidence supports the efficacy of many probiotic strains in the management of gastrointestinal disorders associated with deregulated intestinal barrier function and/or structure. In particular, bifidobacteria have been studied for their efficacy to both prevent and treat a broad spectrum of animal and/or human gut disorders. The aim of the current work was thus to evaluate effects on intestinal barrier function of Bifidobacterium animalis ssp. lactis CNCM-I2494, a strain used in fermented dairy products. A chronic dinitrobenzene sulfonic acid (DNBS)-induced low-grade inflammation model causing gut dysfunction in mice was used in order to study markers of inflammation, intestinal permeability, and immune function in the presence of the bacterial strain. In this chronic low-grade inflammation mice model several parameters pointed out the absence of an over active inflammation process. However, gut permeability, lymphocyte populations, and colonic cytokines were found to be altered. B. animalis ssp. lactis CNCM-I2494 was able to protect barrier functions by restoring intestinal permeability, colonic goblet cell populations, and cytokine levels. Furthermore, tight junction (TJ) proteins levels were also measured by qRT-PCR showing the ability of this strain to specifically normalize the level of several TJ proteins, in particular for claudin-4. Finally, B. lactis strain counterbalanced CD4+ lymphocyte alterations in both spleen and mesenteric lymphoid nodes. It restores the Th1/Th2 ratio altered by the DNBS challenge (which locally augments CD4+ Th1 cells) by increasing the Th2 response as measured by the increase in the production of major representative Th2 cytokines (IL-4, IL-5, and IL-10). Altogether, these data suggest that B. animalis ssp. lactis CNCM-I2494 may efficiently prevent disorders associated with increased barrier permeability.

Overcoming CD4 T helper cell fate restrictions to enhance CD8 T cell and B cell immunity to control persistent LCMV infection

Abstract Persistent viral infection inhibits CD4 Th1 responses, resulting in loss of the CD8 T cell helping Th1 subset and accumulation of B cell helping Tfh cells. Yet, the mechanisms that inhibit CD4 Th1 differentiation and the repercussions of loss of Th1 cells on viral control are unclear. Herein, we demonstrate that the dual upregulation of PD-L1 and IL-10 by chronic type I interferon (IFN-I) signaling during persistent infection suppresses CD4 Th1 priming. Therapeutic blockade of IL-10R and PD-L1 could restore the differentiation of new CD4 Th1 cells, highlighting a new function for PD-L1 to co-inhibit CD4 Th1 priming and identifying a new combinatorial suppressive mechanism during persistent infection. However, CD4 Th1 cells generated by blocking IFN-I signaling in vivo could not be sustained, giving way to a Tfh based response and predominant help to B cells. In vitro polarized virus-specific CD4 Th1 cells also converted towards Tfh cells, however maintained a population of Th1 cells that could enhance exhausted CD8 T cell responses and promote augmented viral clearance. Interestingly, virus-specific CD4 Th17 and Treg cells were also redirected towards Tfh as persistent infection progressed. Thus, our studies have important implications for stability of de novo activated and immunotherapeutic T cells and demonstrate that the redirection away from Th1 responses is a mechanism of immunosuppression to limit the control of persistent viral infection.

Significance of Th17/Treg imbalance in children with primary immune thrombocytopenia

To investigate the significance of Th17/Treg imbalance in the development and treatment of primary immune thrombocytopenia (ITP) in children. Thirty-two children diagnosed with ITP between May and August, 2015 and 22 healthy children were enrolled. Flow cytometry was used to determine the Th17/Treg ratio in peripheral blood of healthy children and children with ITP before and after treatment with immunoglobulin. Compared with the patients with ITP before treatment, the healthy children and the patients treated with immunoglobulin had a significantly lower percentage of Th17 cells in CD4+ T cells, a significantly lower Th17/Treg ratio, and a significantly higher percentage of Treg cells in CD4+ T cells in peripheral blood (P<0.05). In the 32 ITP children treated with immunoglobulin, 20 had complete response, 4 had response, and 8 had no response. The patients with complete response had a significantly lower percentage of Th17 cells in CD4+ T cells and a significantly lower Th17/Treg ratio in peripheral blood than the patients without response (P<0.05). The Th17/Treg imbalance can be found in children with ITP. Immunoglobulin can improve the cellular immune function by regulation of the Th17/Treg ratio. The Th17/Treg ratio may serve as an indicator for assessing the therapeutic effects of ITP.

Durable responses to ibrutinib in patients with relapsed CLL after allogeneic stem cell transplantation.

Ibrutinib, a recently approved inhibitor of Bruton's tyrosine kinase (BTK), has shown great efficacy in patients with high-risk CLL. Nevertheless, there are few data regarding its use in patients who relapsed after allogeneic stem cell transplantation (alloSCT). We report clinical data from five CLL patients treated with ibrutinib for relapse after first or even second allogeneic transplantation. Additionally, we performed analyses on cytokine levels and direct measuring of CD4 Th1 and CD4 Th2 cells to evaluate possible clinically relevant immunomodulatory effects of ibrutinib. All patients achieved partial responses including one minimal residual disease (MRD)-negative remission. Within 1 year of follow-up, no relapse was observed. One patient died of severe pneumonia while on ibrutinib treatment. Beside this, no unexpected adverse events were observed. Flow cytometry and analyses of T cell-mediated cytokine levels (IL10 and TNFα) did not reveal substantial changes in T-cell distribution in favor of a CD4 Th1 T-cell shift in our patients. No acute exacerbation of GvHD was reported. In conclusion, these results support further evaluation of ibrutinib in CLL patients relapsing after alloSCT.

Adjuvant-enhanced antibody and cellular responses to inclusion bodies expressing FhSAP2 correlates with protection of mice to Fasciola hepatica

Fasciola hepatica saposin-like protein-2 (FhSAP2) is a protein differentially expressed in various developmental stages of F. hepatica. Recombinant FhSAP2 has demonstrated the induction of partial protection in mice and rabbits when it is administered subcutaneously (SC) in Freund's adjuvant. Because FhSAP2 is overexpressed in bacteria in the form of inclusion bodies (IBs), we isolated IBs expressing FhSAP2 and tested their immunogenicity when administered SC in mice emulsified in two different adjuvants: QS-21 and Montanide TM ISA720. Animals received three injections containing 20 μg of protein two weeks apart and 4 weeks after the third injection, mice were infected with 10 F. hepatica metacercariae by oral route. The percentages of protection induced by FhSAP2-IBs were estimated to be between 60.0 and 62.5% when compared with adjuvant-vaccinated, infected controls. By determining the levels of IgG1 and IgG2a antibodies and IL-4 and IFNγ cytokines in the serum of experimental animals, it was found that both Th1 and Th2 immune responses were significantly increased in the FhSAP2-IBs vaccinated groups compared with the adjuvant-vaccinated, infected control groups. The adjuvant-vaccinated groups had significantly lower IgG1 to IgG2a ratios and lower IL-4 to IFNγ ratios than the FhSAP2-IBs vaccinated animals, which is indicative of higher levels of Th2 immune responses. Irrespective to the adjuvant used, animals vaccinated with FhSAP2-IBs exhibited significantly higher survival percentage and less liver damage than the adjuvant-control groups. This study suggests that FhSAP2 has potential as vaccine against F. hepatica and that the protection elicited by this molecule could be linked to a mechanism driven by the CD4-Th1 cells.

Exacerbation of lupus nephritis by high sodium chloride related to activation of SGK1 pathway

The objective of this study is to explore the effects of high salt diet (HSD) on the severity of lupus nephritis (LN) and its mechanism. MRL/lpr mice were randomly divided into two groups, which were fed with normal diet or sodium-rich chow and tap. C57BL/6 mice were selected as control. Spleen Th1, Th2, Th17 and Treg cells were detected by flow cytometry. Serum TGF-β and IL-17 were measured by enzyme-linked immunosorbent assay. CD4+ T cells from Systemic Lupus Erythematosus (SLE) patients and healthy donors were treated by NaCl with or without SGK1 inhibitor. Then, Th17 and Treg cells were detected. The HSD MRL/lpr mice had decreased survival rate and increased disease severity. The frequencies of Th1 and Th17 cells increased in HSD treatment group. The ratios of Th1/Th2 and Th17/Treg in HSD treated MRL/lpr mice significantly increased. Serum TGF-β increased after HSD treatment. In vitro, high salt could up-regulate Th17 cells of CD4+ T cells. The effects of high salt treatment on CD4+ T cells were reversed by SGK1 inhibitor. Our findings demonstrated that excessive intake of salt in diet is an aggravating factor for LN. High salt diet may deteriorate LN through SGK1 pathway.

Inhibition of System Xc(-) Transporter Attenuates Autoimmune Inflammatory Demyelination.

T cell infiltration into the CNS is a significant underlying pathogenesis in autoimmune inflammatory demyelinating diseases. Several lines of evidence suggest that glutamate dysregulation in the CNS is an important consequence of immune cell infiltration in neuroinflammatory demyelinating diseases; yet, the causal link between inflammation and glutamate dysregulation is not well understood. A major source of glutamate release during oxidative stress is the system Xc(-) transporter; however, this mechanism has not been tested in animal models of autoimmune inflammatory demyelination. We find that pharmacological and genetic inhibition of system Xc(-) attenuates chronic and relapsing-remitting experimental autoimmune encephalomyelitis (EAE). Remarkably, pharmacological blockade of system Xc(-) 7 d after induction of EAE attenuated T cell infiltration into the CNS, but not T cell activation in the periphery. Mice harboring a Slc7a11 (xCT) mutation that inactivated system Xc(-) were resistant to EAE, corroborating a central role for system Xc(-) in mediating immune cell infiltration. We next examined the role of the system Xc(-) transporter in the CNS after immune cell infiltration. Pharmacological inhibitors of the system Xc(-) transporter administered during the first relapse in a SJL animal model of relapsing-remitting EAE abrogated clinical disease, inflammation, and myelin loss. Primary coculture studies demonstrate that myelin-specific CD4(+) Th1 cells provoke microglia to release glutamate via the system Xc(-) transporter, causing excitotoxic death to mature myelin-producing oligodendrocytes. Taken together, these studies support a novel role for the system Xc(-) transporter in mediating T cell infiltration into the CNS as well as promoting myelin destruction after immune cell infiltration in EAE.

Efficient T-cell priming and activation requires signaling through prostaglandin E2 (EP) receptors.

Understanding the regulation of T-cell responses during inflammation and auto-immunity is fundamental for designing efficient therapeutic strategies against immune diseases. In this regard, prostaglandin E2 (PGE2) is mostly considered a myeloid-derived immunosuppressive molecule. We describe for the first time that T cells secrete PGE2 during T-cell receptor stimulation. In addition, we show that autocrine PGE2 signaling through EP receptors is essential for optimal CD4(+) T-cell activation in vitro and in vivo, and for T helper 1 (Th1) and regulatory T cell differentiation. PGE2 was found to provide additive co-stimulatory signaling through AKT activation. Intravital multiphoton microscopy showed that triggering EP receptors in T cells is also essential for the stability of T cell-dendritic cell (DC) interactions and Th-cell accumulation in draining lymph nodes (LNs) during inflammation. We further demonstrated that blocking EP receptors in T cells during the initial phase of collagen-induced arthritis in mice resulted in a reduction of clinical arthritis. This could be attributable to defective T-cell activation, accompanied by a decline in activated and interferon-γ-producing CD4(+) Th1 cells in draining LNs. In conclusion, we prove that T lymphocytes secret picomolar concentrations of PGE2, which in turn provide additive co-stimulatory signaling, enabling T cells to attain a favorable activation threshold. PGE2 signaling in T cells is also required for maintaining long and stable interactions with DCs within LNs. Blockade of EP receptors in vivo impairs T-cell activation and development of T cell-mediated inflammatory responses. This may have implications in various pathophysiological settings.

Optimizing the efficacy of dual-costimulation cancer therapy by engaging tumor-unrelated CD4 T cell help (TUM2P.1009)

Abstract Tumor escape following immune therapy can be caused by loss of specifically targeted MHC class I-restricted epitopes. It would thus be beneficial to develop therapies that engage multipronged anti-tumor responses. Agonist mAbs to the TNF/TNFR family costimulatory receptors CD134 plus CD137 (dual costimulation) not only elicits CD8+ CTL, but also cytotoxic CD4 Th1 cells that can directly target MHC-II+ tumors. Further, dual costimulated cytotoxic CD4 Th1 cells not only provide linked help to CD8 T cells responding to cross-presented antigen, but can also provide non-linked help that programs Th1/Tc1 functions in antigen-non-responding (bystander) T cells. Here we tested whether engagement of tumor-unrelated CD4 help augments dual costimulation-mediated control of established B16 melanoma that can be induced to express both MHC class I and II. Notably, engagement of tumor-unrelated CD4 T cells dramatically enhanced the ability of dual costimulation to control B16 tumor growth, this effect depended upon both CD8 and CD4 cells, and therapeutic efficacy correlated with increased tumor infiltration of GzmB-expressing effector CD8 and CD4 T cells with a concomitant decrease in Foxp3+CD4+ cells. Interestingly, the dual costimulated tumor-unrelated CD4 helper T cells themselves appear to require help from a CD134-responsive but presumably antigen-non-responding cell to attain their maximal function.

Dectin-1 activation unlocks IL12A expression and reveals the TH1 potency of neonatal dendritic cells

Early life is characterized by a high susceptibility to infection and a TH2-biased CD4 T-cell response to vaccines. Toll-like receptor (TLR) agonists are currently being implemented as new vaccine adjuvants for TH1 activation, but their translation to the field of pediatric vaccines is facing the impairment of neonatal innate TLR responses. We sought to analyze C-type lectin receptor pathways as an alternative or a coactivator to TLRs for neonatal dendritic cell activation for TH1 polarization. Neonatal monocyte-derived dendritic cells (moDCs) were exposed to various combinations of TLR agonists with or without Dectin-1 agonist. IL-12 and IL-23 responses were analyzed at the transcriptional and protein levels after stimulation. The intracellular pathways triggered by combined TLR plus Dectin-1 stimulation was determined by using pharmacologic inhibitors. The capacity of neonatal moDCs to differentiate naive CD4 TH cells was evaluated in cocultures with heterologous neonatal naive T cells. Curdlan was finally tested as an adjuvant within a subunit tuberculosis vaccine in neonatal mice. Simultaneous coactivation through Dectin-1 and TLRs induced robust secretion of IL-12p70 by neonatal moDCs by unlocking transcriptional control on the p35 subunit of IL-12. Both the spleen tyrosine kinase and Raf-1 pathways were involved in this process, allowing differentiation of neonatal naive T cells toward IFN-γ-producing TH1 cells. In vivo a Dectin-1 agonist as adjuvant was sufficient to induce TH1 responses after vaccination of neonatal mice. Coactivation of neonatal moDCs through Dectin-1 allows TLR-mediated IL-12p70 secretion and TH1 polarization of neonatal T cells. Dectin-1 agonists represent a promising TH1 adjuvant for pediatric vaccination.

Deficiency of prolactin-inducible protein leads to impaired Th1 immune response and susceptibility to Leishmania major in mice.

Although the strategic production of prolactin-inducible protein (PIP) at several ports of pathogen entry into the body suggests it might play a role in host defense, no study has directly implicated it in immunity against any infectious agent. Here, we show for the first time that PIP deficiency is associated with reduced numbers of CD4(+) T cells in peripheral lymphoid tissues and impaired CD4(+) Th1-cell differentiation in vitro. In vivo, CD4(+) T cells from OVA-immunized, PIP-deficient mice showed significantly impaired proliferation and IFN-γ production following in vitro restimulation. Furthermore, PIP-deficient mice were highly susceptible to Leishmani major infection and failed to control lesion progression and parasite proliferation. This susceptibility was associated with impaired NO production and leishmanicidal activity of PIP KO macrophages following IFN-γ and LPS stimulation. Collectively, our findings implicate PIP as an important regulator of CD4(+) Th1-cell-mediated immunity.

Factors for early death in rabies- the bitter truth.

Sir, Early death phenomenon in rabies reported by Sadeghi et al.[1] is informative and has long been recognized in patients whose incubation period is shorter than average in patients who were inadequately vaccinated with or without accompanying immunoglobulin and develop rabies.[2] However, we would like to recall other factors related to virus, patients, therapeutic agents, and care providers contributing to early death, so as to introduce appropriate measures to ensure quality in service and enforce patient safety. The high viral load inoculated at the site of bite, which infects motor endplates and motor axons without previous replication in the muscle and its virulence. Those related to patients are anatomical site of bite such as head and neck,[3] or bite in highly innervated areas such as fingers as noted in this case,[1] which has close proximity to central nervous system, and nonfeasibility to infiltrate adequate dose of human rabies immunoglobulin (HRIG). Next is the functional status of the immune system, which may be immune enhancement or “early death” phenomenon through B cells during the incubation period, and/or nonspecific immunosuppressive effect following rabies infection. Rabies nucleoprotein acts as a weak superantigen, and directly induces proliferation of human CD4 Th2 cells bearing the V8 TCR, which suppresses the immunity through polyclonal antibody response.[4] Matters related to therapeutic agents are questionable status of the potency of vaccine and HRIG, due to inherent technical constraints and electricity problems in countries such as India. Certain important factors related to health care providers are nonadherence to World Health Organization (WHO) postexposure prophylaxis protocol. Furthermore, health care providers should avoid prescribing antimalarials and other drugs that interfere with the effectiveness of rabies vaccine or HRIG. To overcome these, we need identification of other responsible factors so as to empower the health care providers for effective services and community health education.[5] Our motto shall be “no death due to rabies” through community education, early intervention, quality assurance of therapeutic agents, and adherence to WHO protocol.

The Role of Non-Cognate T Cell Stimulation during Intracellular Bacterial Infection.

Intra-macrophage bacterial infections cause significant morbidity and mortality in both the developed and developing world. Protective host immune responses to these infections initially requires the activation and expansion of pathogen-specific CD4 Th1 cells within lymphoid tissues and subsequent relocation of these effector cells to sites of infection. After entering infected tissues, the elicitation of Th1 bactericidal activity can be triggered by cognate or non-cognate signals that are delivered by locally infected antigen-presenting cells and innate cells. However, the contribution of non-cognate stimulation to the resolution of bacterial infection remains poorly understood, especially in the context of a Th1 response. Here, we review the current data on Th1 cell activation and expansion in mouse models of Salmonella and Chlamydia infection and discuss the potential role of non-cognate Th1 cell stimulation in these disease models. Greater understanding of this pathway of T cell activation may lead to the design of therapeutics or vaccines to combat intra-macrophage pathogens.

Characterization of an adaptive immune response in microsatellite-instable colorectal cancer

Sporadic or hereditary colorectal cancer (CRC) with microsatellite instability (MSI) is frequently characterized by inflammatory lymphocytic infiltration and tends to be associated with a better outcome than microsatellite stable (MSS) CRC, probably reflecting a more effective immune response. We investigated inflammatory mechanisms in 48 MSI CRCs and 62 MSS CRCs by analyzing: (1) the expression of 48 cytokines using Bio-Plex multiplex cytokine assays, and (2) the in situ immune response by immunohistochemical analysis with antibodies against CD3 (T lymphocytes), CD8 (cytotoxic T lymphocytes), CD45RO (memory T lymphocytes), T-bet (Th1 CD4 cells), and FoxP3 (regulatory T cells). MSI CRC exhibited significantly higher expression of CCL5 (RANTES), CXCL8 (IL-8), CXCL9 (MIG), IL-1β, CXCL10 (IP-10), IL-16, CXCL1 (GROα), and IL-1ra, and lower expression of MIF, compared with MSS CRC. Immunohistochemistry combined with image analysis indicated that the density of CD3+, CD8+, CD45RO+, and T-bet+ T lymphocytes was higher in MSI CRC than in MSS CRC, whereas the number of regulatory T cells (FoxP3+) was not statistically different between the groups. These results indicate that MSI CRC is associated with a specific cytokine expression profile that includes CCL5, CXCL10, and CXCL9, which are involved in the T helper type 1 (Th1) response and in the recruitment of memory CD45RO+ T cells. Our findings highlight the major role of adaptive immunity in MSI CRC and provide a possible explanation for the more favorable prognosis of this CRC subtype.

CD4 T cells with effector memory phenotype and function develop in the sterile environment of the fetus.

The T cell compartment is considered to be naïve and dedicated to the development of tolerance during fetal development. We have identified and characterized a population of fetally developed CD4 T cells with an effector memory phenotype (TEM), which are present in cord blood. This population is polyclonal and has phenotypic features similar to those of conventional adult memory T cells, such as CD45RO expression. These cells express low levels of CD25 but are distinct from regulatory T cells because they lack Foxp3 expression. After T cell receptor activation, neonatal TEM cells readily produced tumor necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We also detected interferon-γ (IFN-γ)-producing T helper 1 (TH1) cells and interleukin-4 (IL-4)/IL-13-producing TH2-like cells, but not IL-17-producing cells. We used chemokine receptor expression patterns to divide this TEM population into different subsets and identified distinct transcriptional programs using whole-genome microarray analysis. IFN-γ was found in CXCR3(+) TEM cells, whereas IL-4 was found in both CXCR3(+) TEM cells and CCR4(+) TEM cells. CCR6(+) TEM cells displayed a genetic signature that corresponded to TH17 cells but failed to produce IL-17A. However, the TH17 function of TEM cells was observed in the presence of IL-1β and IL-23. In summary, in the absence of reported pathology or any major infectious history, T cells with a memory-like phenotype develop in an environment thought to be sterile during fetal development and display a large variety of inflammatory effector functions associated with CD4 TH cells at birth.

Type I interferon suppresses de novo virus-specific CD4 Th1 immunity during an established persistent viral infection.

CD4 T cells are central to orchestrate, sustain, and potentially regenerate antiviral immunity throughout persistent viral infections. Although the evolving immune environment during persistent infection reshapes established CD4 T-cell responses, the fate of naïve CD4 T cells primed in the midst of persistent infection is unclear. We demonstrate that, in marked contrast to the onset of infection, virus-specific CD4 T cells primed during an established persistent infection have diminished ability to develop Th1 responses, to efficiently accumulate in peripheral tissues, and almost exclusively differentiate into T follicular helper cells. Consistent with suppressed Th1 and heightened Tfh differentiation, virus-specific CD4 T cells primed during the established persistent infection provide help to B cells, but only limited help to CD8 T cells. The suppression of de novo Th1 generation and tissue distribution was mediated by chronic type I IFN (IFN-I) production and was effectively restored by blocking IFN-I signaling during CD4 T-cell priming. Thus, we establish a suppressive function of chronic IFN-I signaling and mechanism of immunoregulation during an established persistent virus infection.