CD4+CD25+ regulatory T cells (Treg) are instrumental in the maintenance of immunological tolerance. One critical question is whether Treg can only be generated in the thymus or can differentiate from peripheral CD4+CD25− naive T cells. In this paper, we present novel evidence that conversion of naive peripheral CD4+CD25− T cells into anergic/suppressor cells that are CD25+, CD45RB−/low and intracellular CTLA-4+ can be achieved through costimulation with T cell receptors (TCRs) and transforming growth factor β (TGF-β). Although transcription factor Foxp3 has been shown recently to be associated with the development of Treg, the physiological inducers for Foxp3 gene expression remain a mystery. TGF-β induced Foxp3 gene expression in TCR-challenged CD4+CD25− naive T cells, which mediated their transition toward a regulatory T cell phenotype with potent immunosuppressive potential. These converted anergic/suppressor cells are not only unresponsive to TCR stimulation and produce neither T helper cell 1 nor T helper cell 2 cytokines but they also express TGF-β and inhibit normal T cell proliferation in vitro. More importantly, in an ovalbumin peptide TCR transgenic adoptive transfer model, TGF-β–converted transgenic CD4+CD25+ suppressor cells proliferated in response to immunization and inhibited antigen-specific naive CD4+ T cell expansion in vivo. Finally, in a murine asthma model, coadministration of these TGF-β–induced suppressor T cells prevented house dust mite–induced allergic pathogenesis in lungs.

IntroductionThe complex life cycle of HIV-1 involves critical functional interactions with CD4 ϩ host-cell factors. In addition to CD4 ϩ T cells, CD4 ϩ CCR5 ϩ macrophages represent a primary target and host of HIV-1. Infected macrophages replicate copious amounts of virus at their surface and at intracellular membranes where the virions accumulate in vesicles. 1 Macrophages are not typically subject to viral-induced death and may persist as reservoirs of virus in tissues for long periods of time. 2,3 In addition, infected macrophages may be resistant to antiviral agents, 3-6 and the unique attributes and factors that are enabling for this persistent viral host remain elusive. Critically, all monocytic cells are neither equally permissive to HIV-1 nor supportive of the viral life cycle. In vitro or in vivo, dendritic cells (DCs) may or may not become infected, depending on maturational status 7 ; peripheral-blood monocytes are nearly impervious (Ͻ 1% HIV-1 DNA ϩ ) 8,9 ; and of longstanding interest is the enhanced susceptibility of macrophages to HIV-1 compared with immature monocytes, the basis of which remains a mystery. The fact that macrophages, in culture and in tissues, are more susceptible to infection than monocytes cannot be attributed to levels of membrane CD4 or HIV-1 coreceptor expression 10 or multiple other criteria that have been considered. 11 This fundamental question has obvious significance in that if the monocyte-resistance factor(s) can be identified, opportunities may emerge for manipulating susceptible myeloid populations to impose a restrictive barrier to HIV-1. Limited evidence supports an early postentry block that occurs in association with or shortly after reverse transcription (RT). 8 Beyond the well-established CD4 and CCR5/CXCR4 entry requirements, recent evidence implicates additional membrane and intracellular factors that influence early host-cell responsiveness to productive infection. [11][12][13][14][15][16][17] Among the potential innate intracellular viral antagonists, initially characterized in T cells 18 and more recently in monocytes, 19,20 are cytidine deaminases that edit viral RNA and mutate DNA. These cytoplasmic apolipoprotein B mRNA-editing enzyme catalytic polypeptidelike (APOBEC) subunits, particularly APOBEC3G (hA3G), become incorporated into virions, leading to mutation of nascent HIV-1 DNA formed during reverse transcription and its subsequent degradation. 18,21,22 HIV-1, in turn, inhibits hA3G via HIV-1-encoded viral infectivity factor (Vif)-dependent and -independent pathways to thwart this antiviral defense within the target cell. Vif not only facilitates 26S proteasome-mediated degradation of hA3G but also diminishes its synthesis to collectively exclude hA3G incorporation into the budding virions. [23][24][25] Nonetheless, whether differential HIV-1 susceptibility in myeloid populations could be attributed to constitutively expressed hA3G or any other components of this defensive superfamily had not been addressed.In this study, by oligonucleotide microarr...

Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (APOBEC3G), a cytidine deaminase, is a recently recognized innate intracellular protein with lethal activity against human immunodeficiency virus (HIV). Packaged into progeny virions, APOBEC3G enzymatic activity leads to HIV DNA degradation. As a counterattack, HIV virion infectivity factor (Vif) targets APOBEC3G for proteasomal proteolysis to exclude it from budding virions. Based on the ability of APOBEC3G to antagonize HIV infection, considerable interest hinges on elucidating its mechanism(s) of regulation. In this study, we provide the first evidence that an innate, endogenous host defense factor has the potential to promote APOBEC3G and rebuke the virus-mediated attempt to control its cellular host. We identify interferon (IFN)-α as a potent inducer of APOBEC3G to override HIV Vif neutralization of APOBEC3 proteins that pose a threat to efficient macrophage HIV replication. Our data provide a new dimension by which IFN-α mediates its antiviral activity and suggest a means to render the host nonpermissive for viral replication.

Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (APOBEC3G), a cytidine deaminase, is a recently recognized innate intracellular protein with lethal activity against human immunodefi ciency virus (HIV). Packaged into progeny virions, APOBEC3G enzymatic activity leads to HIV DNA degradation. As a counterattack, HIV virion infectivity factor (Vif) targets APOBEC3G for proteasomal proteolysis to exclude it from budding virions. Based on the ability of APOBEC3G to antagonize HIV infection, considerable interest hinges on elucidating its mechanism(s) of regulation. In this study, we provide the fi rst evidence that an innate, endogenous host defense factor has the potential to promote APOBEC3G and rebuke the virus-mediated attempt to control its cellular host. We identify interferon (IFN)-as a potent inducer of APOBEC3G to override HIV Vif neutralization of APOBEC3 proteins that pose a threat to effi cient macrophage HIV replication. Our data provide a new dimension by which IFN-mediates its antiviral activity and suggest a means to render the host nonpermissive for viral replication.

Gaucher disease (GD), caused by a defect of beta-glucosidase (beta-Glu), is the most common form of sphingolipidosis. We have previously shown that a carbohydrate mimic N-octyl-beta-valienamine (NOV), an inhibitor of beta-Glu, could increase the protein level and enzyme activity of F213I mutant beta-Glu in cultured GD fibroblasts, suggesting that NOV acted as a pharmacological chaperone to accelerate transport and maturation of this mutant enzyme. In the current study, NOV effects were evaluated in GD fibroblasts with various beta-Glu mutations and in COS cells transiently expressing recombinant mutant proteins. In addition to F213I, NOV was effective on N188S, G202R and N370S mutant forms of beta-Glu, whereas it was ineffective on G193W, D409H and L444P mutants. When expressed in COS cells, the mutant proteins as well as the wild-type protein were localized predominantly in the endoplasmic reticulum and were sensitive to Endo-H treatment. NOV did not alter this localization or Endo-H sensitivity, suggesting that it acted in the endoplasmic reticulum. Profiling of N-alkyl-beta-valienamines with various lengths of the acyl chain showed that N-dodecyl-beta-valienamine was as effective as NOV. These results suggest a potential therapeutic value of NOV and related compounds for GD with a broad range of beta-Glu mutations.

Epstein-Barr (EB) virus infection has long been speculated to evoke systemic lupus erythematosus (SLE). Since a virus infection can induce interferon (IFN) system activation, we aimed to discover the relationship between the two in the progression of SLE in a Chinese inpatient cohort. Methods Peripheral blood mononuclear cells and sera were isolated from 116 SLE patients and 76 healthy controls. Antibodies against EBV-VCA (IgM and IgG) and EBNA (IgG) along with IFNα in patient sera were detected with enzyme-linked immunosorbent assays. The EB virus DNA load was detected by real-time quantitative polymerase chain reaction. Peripheral blood mononuclear cells both from patients and controls were isolated immediately. The mRNA from these samples was subjected to real-time PCR for the latent genes EBNA1, EBNA2 and LMP1 of EB virus, as well as four IFN-stimulated genes (ISGs) ( OASL, MX1, ISG15 and LY6E). The antibody results were used to determine the stage of EBV infection (lytic, latent, or previous). Results SLE patients had a higher rate of lytic infection defined as positive EBV-VCA IgM antibody (39.66% vs 10.53%, p = 0.027), but not the EB virus DNA load. Patients with lytic EB virus infection had higher SLEDAI scores than patients with non-lytic infection (15.24 ± 2.63 vs 13.79 ± 3.24, p = 0.012). LMP1 was the only EBV gene that had a higher expression level in SLE patients than in healthy controls (3.26 ± 2.95 vs 1.00 ± 2.89, p = 0.000). It was also positively correlated with SLEDAI scores ( r = 0.462, p = 0.000). Levels of IFNα and the four ISGs were all significantly higher in SLE patients than in healthy controls ( p < 0.05). LMP1 was positively correlated with the four ISGs ( r = 0.403 ∼ 0.494, p < 0.05) in SLE patients but not in healthy controls ( r = -0.153 ∼ 0.129, p > 0.05). Neither EBNA1 nor EBNA2 was correlated with the ISGs in SLE patients or in healthy controls. Conclusions The SLE patients had higher rates of lytic EB virus infection and higher latent gene LMP1 expression, which might be associated with the development and/or the progression of SLE via the type I IFN pathway. The underlying mechanism needs more study.

Background/Aims: MicroRNAs (miRNAs) are a class of small noncoding RNA molecules that play important roles in carcinogenesis and tumor progression. We investigated the roles and mechanisms of miR-200b in human nasopharyngeal carcinoma (NPC). Methods: We used quantitative real-time polymerase chain reaction (qRT-PCR) analyses to measure levels of miR-200b and Notch1 in NPC specimens and cell lines. Human NPC cell lines stably expressing miR-200b or control were used to analyze the tumour-suppressive effect of miR-200b. Luciferase reporter assays were used to determine the association between miR-200b and the Notch1 3' untranslated region. Results: We found that miR-200b is significantly downregulated in NPC tissues and cell lines. Gain-of-function and loss-of-function studies demonstrated that miR-200b suppresses NPC cell growth, migration and invasion in vitro. Importantly, overexpression of miR-200b effectively repressed tumor growth in nude mouse models. Integrated analysis identified Notch1 as a direct and functional target of miR-200b. Overexpression of Notch1 reversed the inhibitory effect of miR-200b on NPC cell growth and invasion. Conclusion: These results indicate that miR-200b exerts tumor-suppressive effects in NPC carcinogenesis through the suppression of Notch1 expression and suggest a therapeutic application of miR-200b in NPC.

The tumour microenvironment (TME) is a complex system composed of cancer cells, stromal cells and immune cells. Regulatory T cells (Tregs) in the TME impede immune surveillance of tumours and suppress antitumor immune responses. Transcription factor forkhead box protein 3 (FOXP3) is the main marker of Tregs, which dominates the function of Tregs. FOXP3 was originally thought to be a Tregs-specific expression molecule, and recent studies have found that FOXP3 is expressed in a variety of tumours with inconsistent functional roles. This review summarizes the recent progress of infiltrating Treg-FOXP3 and tumour-FOXP3 in TME, discusses the communication mechanism between FOXP3 + cells and effector T cells in TME, the relationship between FOXP3 and clinical prognosis, and the potential of FOXP3-targeted therapy.