Environment-induced epigenetic reprogramming in genomic regulatory elements in smoking mothers and their children.

Epigenetic mechanisms have emerged as links between prenatal environmental exposure and disease risk later in life. Here, we studied epigenetic changes associated with maternal smoking at base pair resolution by mapping DNA methylation, histone modifications, and transcription in expectant mothers and their newborn children. We found extensive global differential methylation and carefully evaluated these changes to separate environment associated from genotype-related DNA methylation changes. Differential methylation is enriched in enhancer elements and targets in particular "commuting" enhancers having multiple, regulatory interactions with distal genes. Longitudinal whole-genome bisulfite sequencing revealed that DNA methylation changes associated with maternal smoking persist over years of life. Particularly in children prenatal environmental exposure leads to chromatin transitions into a hyperactive state. Combined DNA methylation, histone modification, and gene expression analyses indicate that differential methylation in enhancer regions is more often functionally translated than methylation changes in promoters or non-regulatory elements. Finally, we show that epigenetic deregulation of a commuting enhancer targeting c-Jun N-terminal kinase 2 (JNK2) is linked to impaired lung function in early childhood.

Differential regulation of T-cell dependent and T-cell independent antibody responses through arginine methyltransferase PRMT1 in vivo.

Protein arginine methyltransferase 1 (PRMT1), a major PRMT in mammalian cells, has been shown to play a crucial role in multiple biological functions in vitro. To explore the role of PRMT1 in B cells in vivo, we generated B cell-specific PRMT1-deficient (Prmt1(-/-) ) mice using a Cre-loxP system. Prmt1(-/-) mice showed a defect in B-cell development with diminished levels of serum antibodies. Antibody responses in Prmt1(-/-) mice were absent after stimulation with the type 2 T cell-independent antigen NP-Ficoll but intact after stimulation with the T cell-dependent antigen NP-OVA. Our findings comprise the first evidence showing that PRMT1 is necessary for lymphocyte functions in vivo.

Promotion of Expansion and Differentiation of Hematopoietic Stem Cells by Interleukin-27 into Myeloid Progenitors to Control Infection in Emergency Myelopoiesis.

Emergency myelopoiesis is inflammation-induced hematopoiesis to replenish myeloid cells in the periphery, which is critical to control the infection with pathogens. Previously, pro-inflammatory cytokines such as interferon (IFN)-α and IFN-γ were demonstrated to play a critical role in the expansion of hematopoietic stem cells (HSCs) and myeloid progenitors, leading to production of mature myeloid cells, although their inhibitory effects on hematopoiesis were also reported. Therefore, the molecular mechanism of emergency myelopoiesis during infection remains incompletely understood. Here, we clarify that one of the interleukin (IL)-6/IL-12 family cytokines, IL-27, plays an important role in the emergency myelopoiesis. Among various types of hematopoietic cells in bone marrow, IL-27 predominantly and continuously promoted the expansion of only Lineage-Sca-1+c-Kit+ (LSK) cells, especially long-term repopulating HSCs and myeloid-restricted progenitor cells with long-term repopulating activity, and the differentiation into myeloid progenitors in synergy with stem cell factor. These progenitors expressed myeloid transcription factors such as Spi1, Gfi1, and Cebpa/b through activation of signal transducer and activator of transcription 1 and 3, and had enhanced potential to differentiate into migratory dendritic cells (DCs), neutrophils, and mast cells, and less so into macrophages, and basophils, but not into plasmacytoid DCs, conventional DCs, T cells, and B cells. Among various cytokines, IL-27 in synergy with the stem cell factor had the strongest ability to augment the expansion of LSK cells and their differentiation into myeloid progenitors retaining the LSK phenotype over a long period of time. The experiments using mice deficient for one of IL-27 receptor subunits, WSX-1, and IFN-γ revealed that the blood stage of malaria infection enhanced IL-27 expression through IFN-γ production, and the IL-27 then promoted the expansion of LSK cells, differentiating and mobilizing them into spleen, resulting in enhanced production of neutrophils to control the infection. Thus, IL-27 is one of the limited unique cytokines directly acting on HSCs to promote differentiation into myeloid progenitors during emergency myelopoiesis.

Vaccination with OVA-bound nanoparticles encapsulating IL-7 inhibits the growth of OVA-expressing E.G7 tumor cells in vivo.

Immunotherapy has gained special attention due to its specific effects on tumor cells and systemic action to block metastasis. We recently demonstrated that ovalbumin (OVA) conjugated to the surface of nanoparticles (NPs) (OVA­NPs) can manipulate humoral immune responses. In the present study, we aimed to ascertain whether vaccination with OVA-NPs entrapping IL-7 (OVA-NPs-IL-7) are able to induce antitumor immune responses in vivo. Pretreatment with a subcutaneous inoculation of OVA-NPs delayed the growth of thymic lymphoma cells expressing a model tumor antigen OVA (E.G7-OVA), and OVA-NPs-IL-7 substantially blocked the growth of E.G7-OVA tumor cells, although NPs-IL-7 alone had a meager effect, as assessed by the mean tumor size and the percentage of tumor-free mice. However, pretreatment with OVA-NPs-IL-7 failed to reduce the growth of parental thymic tumor cells, suggesting that the antitumor effect was antigen-specific. A tetramer assay revealed that vaccination with OVA-NPs-IL-7 tended to enhance the proportion of cytotoxic T cells (CTLs) specific for OVA. When the tumor-free mice inoculated with OVA-NPs-IL-7 plus EG.7 cells were rechallenged with E.G7-OVA cells, they demonstrated reduced growth compared with that in the control mice. Thus, a single subcutaneous injection of OVA-NPs-IL-7 into mice induced tumor-specific and also memory-like immune responses, resulting in regression of tumor cells. Antigens on NPs entrapping IL-7 would be a promising carrier to develop and enhance immune responses, including humoral and cellular immunity as well as a method of drug delivery to a specific target of interest.

OVA-bound nanoparticles induce OVA-specific IgG1, IgG2a, and IgG2b responses with low IgE synthesis.

There is an urgent requirement for a novel vaccine that can stimulate immune responses without unwanted toxicity, including IgE elevation. We examined whether antigen ovalbumin (OVA) conjugated to the surface of nanoparticles (NPs) (OVA-NPs) with average diameter of 110nm would serve as an immune adjuvant. When BALB/c mice were immunized with OVA-NPs, they developed sufficient levels of OVA-specific IgG1 antibody responses with low levels of IgE synthesis, representing helper T (Th)2-mediated humoral immunity. OVA-specific IgG2a and IgG2b responses (i.e., Th1-mediated immunity) were also induced by secondary immunization with OVA-NPs. As expected, immunization with OVA in alum (OVA-alum) stimulated humoral immune responses, including IgG1 and IgE antibodies, with only low levels of IgG2a/IgG2b antibodies. CD4-positive T cells from mice primed with OVA-NPs produced substantial levels of IL-21 and IL-4, comparable to those from OVA-alum group. The irradiated mice receiving OVA-NPs-primed B cells together with OVA-alum-primed T cells exhibited enhanced anti-OVA IgG2b responses relative to OVA-alum-primed B cells and T cells following stimulation with OVA-NPs. Moreover, when OVA-NPs-primed, but not OVA-alum-primed, B cells were cultured in the presence of anti-CD40 monoclonal antibody, IL-4, and IL-21, or LPS plus TGF-ß in vitro, OVA-specific IgG1 or IgG2b antibody responses were elicited, suggesting that immunization with OVA-NPs modulates B cells to generate IgG1 and IgG2b responses. Thus, OVA-NPs might exert their adjuvant action on B cells, and they represent a promising potential vaccine for generating both IgG1 and IgG2a/IgG2b antibody responses with low IgE synthesis.

Immunosurveillance markers may predict patients who can discontinue imatinib therapy without relapse.

Tyrosine kinase inhibitors have dramatically improved the treatment of chronic myeloid leukemia. Recent evidence revealed that some patients with chronic myeloid leukemia can stop imatinib without relapse after achieving a complete molecular response. This review discusses the possible predictive markers to identify these patients who can stop imatinib without relapse.

Phosphorylation of the adaptor ASC acts as a molecular switch that controls the formation of speck-like aggregates and inflammasome activity.

The inflammasome adaptor ASC contributes to innate immunity through the activation of caspase-1. Here we found that signaling pathways dependent on the kinases Syk and Jnk were required for the activation of caspase-1 via the ASC-dependent inflammasomes NLRP3 and AIM2. Inhibition of Syk or Jnk abolished the formation of ASC specks without affecting the interaction of ASC with NLRP3. ASC was phosphorylated during inflammasome activation in a Syk- and Jnk-dependent manner, which suggested that Syk and Jnk are upstream of ASC phosphorylation. Moreover, phosphorylation of Tyr144 in mouse ASC was critical for speck formation and caspase-1 activation. Our results suggest that phosphorylation of ASC controls inflammasome activity through the formation of ASC specks.

IL-27 enhances the expression of TRAIL and TLR3 in human melanomas and inhibits their tumor growth in cooperation with a TLR3 agonist poly(I:C) partly in a TRAIL-dependent manner.

Interleukin (IL)-27 is a member of the IL-6/IL-12 cytokine family and possesses potent antitumor activity, which is mediated by multiple mechanisms. Toll-like receptor (TLR)3 is the critical sensor of the innate immune system that serves to identify viral double-stranded RNA. TLR3 is frequently expressed by various types of malignant cells, and recent studies reported that a synthetic TLR3 agonist, polyinosinic-polycytidylic acid [poly(I:C)], induces antitumor effects on malignant cells. In the present study, we have explored the effect of IL-27 on human melanomas and uncovered a previously unknown mechanism. We found that IL-27 inhibits in vitro tumor growth of human melanomas and greatly enhances the expression of TNF-related apoptosis inducing ligand (TRAIL) in a dose-dependent manner. Neutralizing antibody against TRAIL partly but significantly blocked the IL-27-mediated inhibition of tumor growth. In addition, IL-27 and poly(I:C) cooperatively augmented TRAIL expression and inhibited tumor growth. The cooperative effect could be ascribed to the augmented expression of TLR3, but not retinoic acid-inducible gene-I or anti-melanoma differentiation-associated gene 5, by IL-27. The inhibition of tumor growth by the combination was also significantly abrogated by anti-TRAIL neutralizing antibody. Moreover, IL-27 and poly(I:C) cooperatively suppressed in vivo tumor growth of human melanoma in immunodeficient mice. Taken together, these results suggest that IL-27 enhances the expression of TRAIL and TLR3 in human melanomas and inhibits their tumor growth in cooperation with poly(I:C), partly in a TRAIL-dependent manner. Thus, IL-27 and the combination of IL-27 and poly(I:C) may be attractive candidates for cancer immunotherapy.

Requirement of apoptosis-inducing kinase 1 for the induction of bronchial asthma following stimulation with ovalbumin.

BACKGROUND: Bronchial asthma is a chronic inflammatory disease of the airway. Apoptosis signal-regulating kinase 1 (ASK1), a member of the mitogen-activated protein kinase kinase kinase family, is activated by environmental stress and plays a crucial role in the induction of apoptosis and inflammation. To examine whether ASK1 is involved in the induction of bronchial asthma, we investigated the role of ASK1 using a genetic approach in the production of cytokines, as well as the development of airway hyperreactivity (AHR) and antibody responses using a murine airway inflammation model. METHODS: ASK1-deficient (ASK1(-/-)) and control wild-type (WT) mice were immunized with ovalbumin (OVA) without alum intraperitoneally, followed by intranasal administration of OVA. Airway infiltration of inflammatory cells, cytokine production, AHR and antibody production were assayed. The asthmatic phenotype was assessed following intranasal administration of IL-13 or TNF-α. RESULTS: ASK1(-/-) mice sensitized with OVA displayed an impaired inflammatory cell infiltration into airways and a decreased AHR relative to WT mice. Moreover, the production of OVA-specific IgE antibodies and proasthmatic cytokines (IL-5, IL-13 and TNF-α) was substantially reduced in OVA-stimulated ASK1(-/-) mice. Intranasal administration of IL-13 and OVA enhanced the accumulation of inflammatory cells in OVA-primed ASK1(-/-) mice. The OVA-induced AHR in response to methacholine was enhanced by IL-13 in WT mice but not ASK1(-/-) mice. CONCLUSIONS: The ASK1 signaling pathway regulates the OVA-induced asthmatic phenotype, specifically AHR sensitivity and cytokine production. Therefore, the ASK1 signaling pathway is a promising target for therapeutic intervention in some asthmatic patients.

Pivotal roles of T-helper 17-related cytokines, IL-17, IL-22, and IL-23, in inflammatory diseases.

T-helper 17 (Th17) cells are characterized by producing interleukin-17 (IL-17, also called IL-17A), IL-17F, IL-21, and IL-22 and potentially TNF- α and IL-6 upon certain stimulation. IL-23, which promotes Th17 cell development, as well as IL-17 and IL-22 produced by the Th17 cells plays essential roles in various inflammatory diseases, such as experimental autoimmune encephalomyelitis, rheumatoid arthritis, colitis, and Concanavalin A-induced hepatitis. In this review, we summarize the characteristics of the functional role of Th17 cells, with particular focus on the Th17 cell-related cytokines such as IL-17, IL-22, and IL-23, in mouse models and human inflammatory diseases.

Sustained upregulation of effector natural killer cells in chronic myeloid leukemia after discontinuation of imatinib.

A number of CML patients who achieve a sustained complete molecular response (CMR) for at least 2 years during imatinib (IM) therapy can discontinue IM without relapse. With the long-term goal of developing immunological criteria for managing IM therapy in CML patients, we compared the immunophenotypic profiles of three groups of CML patients: those who received IM and had a CMR for more than two consecutive years (CMR group); patients who received IM and did not have a sustained CMR but maintained a major molecular response for more than 2 years (fluctuating CMR group); and patients with a sustained CMR for more than 6 months after IM discontinuation (STOP-IM group), together with healthy controls. The percentages of effector populations of natural killer (NK) cells, such as interferon (IFN)-γ(+) CD3(-) CD56(+) cells, were significantly higher in the STOP-IM and CMR groups than in the fluctuating CMR and control groups. The elevated levels of these effector NK cells were sustained for more than 3 years after IM discontinuation. In contrast, the percentages of effector memory CD8(+) T cells, such as IFN-γ(+) CCR7(-) CD45RO(+) CD8(+) cells, were significantly higher in the STOP-IM and control groups than in the CMR and fluctuating CMR groups, possibly owing to IM intake. These results suggest that the immunological activation status of NK cells contributes to CMR maintenance. Higher activation levels of effector NK cells in CML patients being treated with IM might reflect minimization of BCR-ABL1 transcript levels and therefore could be additive information for determining whether to stop IM.

Arginine methylation regulates antibody responses through modulating cell division and isotype switching in B cells.

Protein arginine methylation plays crucial roles, including signal transduction, transcriptional control, cell proliferation and/or differentiation. B cells undergo clonal division, isotype switching and differentiate into antibody forming cells following stimulation with Toll-like receptor-ligand, lipopolysaccharide (LPS) and T cell-derived signals, including CD40-ligand (CD40-L) and interleukin 4 (IL-4). Whether protein arginine methylation affects B cell division and/or isotype switching to IgG1 in response to LPS, IL-4, and CD40-L was examined using the arginine methyl transferase inhibitor adenosine-2',3'-dialdehyde (AdOx). Addition of AdOx substantially reduced the number of division cycles of stimulated B cells, whereas cell viability remained intact. Upon stimulation with LPS/IL-4/CD40-L, the proportion of surface IgG1 positive cells in each division cycle was slightly diminished by AdOx. However, the degree of expression of γ1 germ line transcript and activation-induced cytidine deaminase (AID) in response to LPS/IL-4/CD40-L were unaffected by addition of AdOx, suggesting that AdOx influences class switch recombination independent of AID expression through transcriptional control. Taken together, arginine methylation appears to be involved in B cell isotype switching, as well as in clonal expansion of B cells in response to LPS/IL-4/CD40-L.

IL-27 promotes nitric oxide production induced by LPS through STAT1, NF-κB and MAPKs.

Interleukin (IL)-27, a member of the IL-6/IL-12 heterodimeric cytokine family, induces pro-inflammatory responses including early T helper (Th)1 differentiation and generation of cytotoxic T lymphocytes, and also anti-inflammatory responses including the differentiation to IL-10-producing regulatory T cells, inhibition of Th2 and Th17 differentiation, and suppression of pro-inflammatory cytokine production. Nitric oxide (NO) is a potent source of reactive nitrogen species that play an important role in killing intracellular pathogens and forms a crucial component of host defense. Inducible NO synthase (iNOS), which catalyzes the production of NO, is induced by a range of stimuli including cytokines and microbes. Recently, IL-27 was reported to play an anti-inflammatory role in microglia by blocking oncostatin M-induced iNOS expression and neuronal toxicity. In the present study, we investigated the effects of IL-27 on NO production in thioglycollate-elicited peritoneal macrophages. IL-27 together with lipopolysaccharide (LPS) induced morphological change into more spread and elongated cells and synergistically enhanced NO production. The combined stimulation also enhanced iNOS mRNA expression and the NO production was abrogated by an iNOS inhibitor, NG-monomethyl L-arginine. The synergistic NO production could be attributed to the augmented Toll-like receptor (TLR)4 mRNA expression by the combination. Signal transducer and activator of transcription (STAT)1 was indispensable for the morphological change and NO production. The combination induced nuclear factor κB (NF-κB) translocation into nuclear and phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), and their inhibitors suppressed NO production. These results suggest that in contrast to the anti-proinflammatory role in microglia, IL-27 exerts a pro-inflammatory role by enhancing NO production in peritoneal macrophages stimulated with LPS through activation of STAT1, NF-κB and MAPKs.

PKC-δ mediates interferon-α-induced apoptosis through c-Jun NH2-terminal kinase activation.

BACKGROUND: Interferon-α (IFN-α) exerts an anti-tumor effect at least through induction of apoptosis in a variety of types including B lymphoma cells. We recently found that IFN-α induced a sustained activation of c-Jun NH2-terminal kinase1 (JNK1), which is implicated in activation of the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) promoter. In the present study, we explored upstream component(s) of the prolonged IFN-α-initiated activation of JNK1. RESULTS: IFN-α caused activation of PKC-δ in Daudi B lymphoma cells and myeloma U266 cells, as detected by Western blotting using a monoclonal antibody specific for the phosphorylated form of PKC-δ. The dominant-negative form of mutant PKC-δ (dnPKC-δ) reduced the IFN-α-induced JNK1 activation, TRAIL promoter activity, loss of mitochondrial membrane potential (ΔΨm), and increase in propidium iodide (PI) positive cells. The IFN-α-induced activation of JNK1 and the TRAIL promoter was also attenuated by the PKC-δ inhibitor rottlerin. Moreover, a constitutively active form of mutant PKC-δ enhanced the IFN-α-induced TRAIL promoter activity and loss of ΔΨm in Daudi B lymphoma cells. In addition, IFN-α-induced Ser727 phosphorylation of Stat1 was also abrogated by dnPKC-δ. CONCLUSIONS: IFN-α induced JNK1 activation via PKC-δ, leading to upregulation of TRAIL. The interaction of the consequent enhanced TRAIL expression with TRAIL-receptor results in a loss of ΔΨm and increase in PI positive cells. The IFN-α-induced apoptotic events may also be affected by the Ser727-Stat1 induced by PKC-δ-mediated signaling component(s).

Thy28 partially prevents apoptosis induction following engagement of membrane immunoglobulin in WEHI-231 B lymphoma cells.

Thy28 protein is conserved among plants, bacteria, and mammalian cells. Nuclear Thy28 protein is substantially expressed in testis, liver, and immune cells such as lymphocytes. Lymphocyte apoptosis plays a crucial role in homeostasis and formation of a diverse lymphocyte repertoire. In this study, we examined whether Thy28 affects induction of apoptosis in WEHI-231 B lymphoma cells following engagement of membrane immunoglobulin (mIg). Once they were established, the Thy28-overexpressing WEHI-231 cells showed similar expression levels of IgM and class I major histocompatibility complex (MHC) molecule compared with controls. The Thy28-overexpressing cells were considerably resistant to loss of mitochondrial membrane potential (ΔΨm), caspase-3 activation, and increase in annexin-positive cells upon mIg engagement. These changes were concomitant with an increase in G1 phase associated with upregulation of p27(Kip1). The anti-IgM-induced sustained activation of c-Jun N-terminal kinase (JNK), which was associated with late-phase hydrogen peroxide (H(2)O(2)) production, was partially reduced in the Thy28-expressing cells relative to controls. Taken together, the data suggest that in WEHI-231 B lymphoma cells, Thy28 regulates mIg-mediated apoptotic events through the JNK-H(2)O(2) activation pathway, concomitant with an accumulation of cells in G1 phase associated with upregulation of p27(Kip1) in WEHI-231 B lymphoma cells.

Regulation of the development of acute hepatitis by IL-23 through IL-22 and IL-17 production.

IL-23 plays a critical role in the expansion of highly proinflammatory Th17 cells secreting IL-17 and IL-22. Recently, we demonstrated that Notch signaling drives IL-22 secretion through the aryl hydrocarbon receptor (AHR) and plays a protective role in Con A-induced hepatitis. In this study, we investigated the role of IL-23 in hepatitis using IL-23p19- and IL-17-deficient mice. In WT mice, the injection of Con A induced the upregulation of various cytokines, which included IL-23, IL-22, IL-17, IFN-γ and TNF-α. In IL-23p19-deficient mice, exacerbated hepatitis was observed and serum IL-22 and IL-17 levels were greatly reduced, whereas in IL-17-deficient mice, ameliorated hepatitis was observed. The injection of exogenous IL-22 protected p19-deficient mice from hepatitis, whereas the injection of exogenous IL-23 significantly increased the serum levels of not only IL-22 but also IL-17, and less effectively protected against hepatitis in IL-17-dependent and -independent manners. Finally, it was revealed that STAT3, STAT4 and Notch contributed to the production of both the cytokines, and that the AHR was important only for IL-22 production in response to Con A and IL-23 in liver mononuclear cells. These results suggest that IL-23 plays a protective role in hepatitis through IL-22 production and also a pathological role via IL-17-dependent and -independent mechanisms.

IL-27 suppresses RANKL expression in CD4+ T cells in part through STAT3.

The receptor activator of NF-κB ligand (RANKL), which is expressed by not only osteoblasts but also activated T cells, plays an important role in bone-destructive diseases such as rheumatoid arthritis. IL-27, a member of the IL-6/IL-12 family cytokines, activates STAT1 and STAT3, promotes early helper T (Th)1 differentiation and generation of IL-10-producing type 1 regulatory T (Tr1) cells, and suppresses the production of inflammatory cytokines and inhibits Th2 differentiation. In addition, IL-27 was recently demonstrated to not only inhibit Th17 differentiation but also directly act on osteoclast precursor cells and suppress RANKL-mediated osteoclastogenesis through STAT1-dependent inhibition of c-Fos, leading to amelioration of the inflammatory bone destruction. In the present study, we investigated the effect of IL-27 on the expression of RANKL in CD4(+) T cells. We found that IL-27 greatly inhibits cell surface expression of RANKL on naive CD4(+) T cells activated by T cell receptor ligation and secretion of its soluble RANKL as well. The inhibitory effect was mediated in part by STAT3 but not by STAT1 or IL-10. In contrast, in differentiated Th17 cells, IL-27 much less efficiently inhibited the RANKL expression after restimulation. Taken together, these results indicate that IL-27 greatly inhibits primary RANKL expression in CD4(+) T cells, which could contribute to the suppressive effects of IL-27 on the inflammatory bone destruction.

Regulation of antitumor immune responses by the IL-12 family cytokines, IL-12, IL-23, and IL-27.

The interleukin (IL)-12 family, which is composed of heterodimeric cytokines including IL-12, IL-23, and IL-27, is produced by antigen-presenting cells such as macrophages and dendritic cells and plays critical roles in the regulation of helper T (Th) cell differentiation. IL-12 induces IFN-γ production by NK and T cells and differentiation to Th1 cells. IL-23 induces IL-17 production by memory T cells and expands and maintains inflammatory Th17 cells. IL-27 induces the early Th1 differentiation and generation of IL-10-producing regulatory T cells. In addition, these cytokines induce distinct immune responses to tumors. IL-12 activates signal transducers and activator of transcription (STAT)4 and enhances antitumor cellular immunity through interferon (IFN)-γ production. IL-27 activates STAT1, as does IFN-γ and STAT3 as well, and enhances antitumor immunity by augmenting cellular and humoral immunities. In contrast, although exogenously overexpressed IL-23 enhances antitumor immunity via memory T cells, endogenous IL-23 promotes protumor immunity through STAT3 activation by inducing inflammatory responses including IL-17 production.

Enhanced T cell-independent antibody responses in c-Jun N-terminal kinase 2 (JNK2)-deficient B cells following stimulation with CpG-1826 and anti-IgM.

Although c-Jun NH2-terminal kinase (JNK) 1 and JNK2 have been demonstrated to modulate T cell activation, role of JNKs in B cell activation remains largely unclear. Phosphorylation of JNK2 was increased in murine B cells following stimulation with either anti-IgM or CpG-1826 oligonucleotide (ODN) alone, with a further increase by a combined stimulation with anti-IgM and CpG-1826 ODN. In this study, we examined whether antibody production induced by CpG ODN and/or anti-IgM is affected in B cells from JNK2-deficient (JNK2-/-) mice. After stimulation with CpG ODN or both CpG ODN and anti-IgM, JNK2-/- B cells displayed an enhanced antibody production of IgG1 and IgG2a, with less pronounced in IgG2b production, as assessed by enzyme-linked immunoassay (ELISA). However, IgM production in JNK2-/- B cells by CpG ODN was comparable to that in WT B cells. TLR9 expression was increased in JNK2-/- B cells after stimulation with anti-IgM or both CpG ODN and anti-IgM, suggesting that the anti-IgM/CpG ODN-induced enhancement of antibody production is partly due to the increased expression of TLR9. The enhanced antibody production in JNK2-/- B cells by the combined stimulation does not appear to involve either increased class switch recombination or cell proliferation. Our results provide useful information on the role of JNK2 in antibody responses mediated by T cell-independent antigens.

A pivotal role for interleukin-27 in CD8+ T cell functions and generation of cytotoxic T lymphocytes.

Cytotoxic T lymphocytes (CTLs) play a critical role in the control of various cancers and infections, and therefore the molecular mechanisms of CTL generation are a critical issue in designing antitumor immunotherapy and vaccines which augment the development of functional and long-lasting memory CTLs. Interleukin (IL)-27, a member of the IL-6/IL-12 heterodimeric cytokine family, acts on naive CD4+ T cells and plays pivotal roles as a proinflammatory cytokine to promote the early initiation of type-1 helper differentiation and also as an antiinflammatory cytokine to limit the T cell hyperactivity and production of pro-inflammatory cytokines. Recent studies revealed that IL-27 plays an important role in CD8+ T cells as well. Therefore, this article reviews current understanding of the role of IL-27 in CD8+ T cell functions and generation of CTLs.