Regional and temporal expression patterns of interleukin-10, interleukin-10 receptor and adhesion molecules in the rat spinal cord during chronic relapsing EAE

Adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mediate leukocyte infiltration into the CNS, in experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). Because exogenous interleukin-10 (IL-10) inhibits ICAM-1 and VCAM-1 expression and clinical EAE, we hypothesize that endogenous IL-10 signaling may suppress expression of adhesion molecules. In a rat model of chronic relapsing EAE, expression levels of IL-10 and its receptor (IL-10R1), ICAM-1 and VCAM-1 mRNA in the spinal cord are markedly increased, whereas levels of IL-10 mRNA remain relatively low. The temporal pattern of mRNA and protein expression showed marked differences between spinal cord levels. During relapse, IL-10, IL-10R1, ICAM-1, VCAM-1 mRNA levels and neurological scores show positive correlations. We conclude that endogenous IL-10 is not a crucial factor inhibiting adhesion molecule expression in this model.

Low penetrance, broad resistance, and favorable outcome of interleukin 12 receptor beta1 deficiency: medical and immunological implications

The clinical phenotype of interleukin 12 receptor beta1 chain (IL-12Rbeta1) deficiency and the function of human IL-12 in host defense remain largely unknown, due to the small number of patients reported. We now report 41 patients with complete IL-12Rbeta1 deficiency from 17 countries. The only opportunistic infections observed, in 34 patients, were of childhood onset and caused by weakly virulent Salmonella or Mycobacteria (Bacille Calmette-Guérin -BCG- and environmental Mycobacteria). Three patients had clinical tuberculosis, one of whom also had salmonellosis. Unlike salmonellosis, mycobacterial infections did not recur. BCG inoculation and BCG disease were both effective against subsequent environmental mycobacteriosis, but not against salmonellosis. Excluding the probands, seven of the 12 affected siblings have remained free of case-definition opportunistic infection. Finally, only five deaths occurred in childhood, and the remaining 36 patients are alive and well. Thus, a diagnosis of IL-12Rbeta1 deficiency should be considered in children with opportunistic mycobacteriosis or salmonellosis; healthy siblings of probands and selected cases of tuberculosis should also be investigated. The overall prognosis is good due to broad resistance to infection and the low penetrance and favorable outcome of infections. Unexpectedly, human IL-12 is redundant in protective immunity against most microorganisms other than Mycobacteria and Salmonella. Moreover, IL-12 is redundant for primary immunity to Mycobacteria and Salmonella in many individuals and for secondary immunity to Mycobacteria but not to Salmonella in most.

Induction of experimental autoimmune encephalomyelitis in IL-12 receptor-beta 2-deficient mice: IL-12 responsiveness is not required in the pathogenesis of inflammatory demyelination in the central nervous system

IL-12 is thought to be involved in the susceptibility to experimental autoimmune encephalomyelitis (EAE), a Th1 cell-mediated autoimmune disorder of the CNS. IL-12 signals through a heterodimeric receptor (IL-12Rbeta1/IL-12Rbeta2), whose beta2-chain is up-regulated on activated, autoreactive Th1 cells. Contrary to the expectation that the absence of IL-12Rbeta2 would protect from EAE, we found that IL-12Rbeta2-deficient mice developed earlier and more severe disease, with extensive demyelination and CNS inflammation. The inflammatory cells were mainly comprised of CD4(+) T cells, monocyte/macrophages, and dendritic cells. Compared to wild-type mice, IL-12Rbeta2-deficient mice exhibited significantly increased autoantigen-induced proliferative response and increased production of TNF-alpha, GM-CSF, IL-17, IL-18/IL-18Ralpha, and NO. In addition, we found significantly increased levels of IL-23p19 mRNA expression in spleen cells from immunized IL-12Rbeta2(-/-) mice compared with wild-type mice. These findings indicate that IL-12 responsiveness is not required in the pathogenesis of inflammatory demyelination in the CNS, and that, in the absence of IL-12Rbeta2, increased IL-23 and other inflammatory molecules may be responsible for increased severity of EAE.

Complex events in the evolution of the human pseudoautosomal region 2 (PAR2)

The 320-kb human pseudoautosomal region 2 (PAR2) at the tips of the long arms of the X and Y chromosomes is thought to have been duplicated onto the Y chromosome recently in primate evolution. The four genes within PAR2 have been proposed to constitute two zones with different base ratios and transcription, one of which was added recently to the X chromosome. To test this hypothesis, we cloned and mapped PAR2 genes in other species, the lemur, the cat, and a marsupial, the tammar wallaby. None of the human PAR2 genes colocalized with human PAR1 genes in the marsupial genome, confirming that the human PAR1 and PAR2 evolved independently. Of the four PAR2 genes, only SYBL1 was located on the X chromosome in all species, including marsupials, so it was part of the ancient X. HSPRY3 localized to the X in all the eutherians, but not marsupial, so it must have been added to the X 80-130 million years ago. CXYorf1 was present on the X in primates and also in mouse, but autosomal in wallaby, suggesting a later addition 70-130 million years ago, and IL9R was on the X only in primate, suggesting addition 60-70 million years ago. The results therefore demonstrate that at least two independent additions were necessary for PAR2 evolution. The present gene order on the human X also requires two inversions. The complicated evolutionary pathway supports the hypothesis that terminal interchromosomal rearrangements are common in regions unpaired at meiosis.

Interleukin-12 and the regulation of innate resistance and adaptive immunity

Interleukin-12 (IL-12) is a heterodimeric pro-inflammatory cytokine that induces the production of interferon-gamma (IFN-gamma), favours the differentiation of T helper 1 (T(H)1) cells and forms a link between innate resistance and adaptive immunity. Dendritic cells (DCs) and phagocytes produce IL-12 in response to pathogens during infection. Production of IL-12 is dependent on differential mechanisms of regulation of expression of the genes encoding IL-12, patterns of Toll-like receptor (TLR) expression and cross-regulation between the different DC subsets, involving cytokines such as IL-10 and type I IFN. Recent data, however, argue against an absolute requirement for IL-12 for T(H)1 responses. Our understanding of the relative roles of IL-12 and other factors in T(H)1-type maturation of both CD4+ and CD8+ T cells is discussed here, including the participation in this process of IL-23 and IL-27, two recently discovered members of the new family of heterodimeric cytokines.

Expression and function of interleukin-11 and its receptor alpha in the human endometrium

The interleukin-11 (IL-11) receptor alpha has an important function in decidualization of mouse endometrial stroma but the function of IL-11 and its receptor in the human endometrium remains unknown. The mRNA for IL-11 and its receptor alpha in human endometrial tissue samples were analysed by semi-quantitative RT-PCR and RNase protection assays respectively. The proteins were detected in frozen endometrial tissue samples by immunofluorescence. The effect of heparin-binding epidermal growth factor (HB-EGF) on secretion of IL-11 by cultured endometrial stromal cells was assessed by enzyme-linked immunosorbent assay. The proliferative potential of IL-11 in endometrial stromal cells was assessed by [(3)H]thymidine uptake. IL-11 and its receptor alpha mRNAs and proteins were detected in the endometrium throughout the cycle. Distinct patterns of localization of the ligand and receptor were observed. HB-EGF induced IL-11 secretion by cultured stromal cells, and IL-11 induced [(3)H]thymidine uptake by these cells. Our data suggest that IL-11-receptor interactions may perform different functions in the human endometrium at different stages of the cycle, and that secretion of IL-11 is modulated by local growth factors.

Cloning of porcine interleukin (IL)-12 receptor beta2 (IL-12Rbeta2) gene and its application to a rapid biological assay for human/porcine IL-12

Porcine IL-12Rbeta2 gene was cloned from mRNA preparation of mitogen-activated peripheral blood mononuclear cells (PBMCs), and its complete nucleotide sequence was determined. To confirm the biological function, the entire open reading frame (ORF) was re-cloned into a mammalian expression vector, pcDNA3.1/Zeo(+), at the downstream of CMV promoter, and introduced to a Th1-like human lymphoma cell line, Jurkat E6-1. Antibiotic-resistant cells retaining the expression construct were selected then, isolated by the limiting dilution method. An established clone (10B10) constitutively expressed chimeric IL-12Rs composed of intrinsic (human) beta1 and extrinsic (porcine) beta2 subunits, and produced interferon (IFN)-gamma in response to IL-12 of both species with optimal PHA/PMA stimulation. The production of IFN-gamma was observed as early as 42 h after culture and appeared to be dose-dependent within the range between 20 and 2000 pg/ml. Thus, this clone not only reacts with IL-12 of both species but also provides a useful tool for quick and sensitive detection of IL-12 bioactivity.

Functional changes of dendritic cells derived from allogeneic partial liver graft undergoing acute rejection in rats

AIM: To investigate functional change of dendritic cells (DCs) derived from allogeneic partial liver graft undergoing acute rejection in rats.

METHODS: Allogeneic (SD rat to LEW rat) whole and 50% partial liver transplantation were performed. DCs from liver grafts 0 h and 4 d after transplantation were isolated and propagated in the presence of GM-CSF in vitro. Morphological characteristics of DCs propagated for 4 d and 10 d were observed by electron microscopy. Phenotypical features of DCs propagated for 10 d were analyzed by flow cytometry. Expression of IL-12 protein and IL-12 receptor mRNA in DCs propagated for 10 d was also measured by Western blotting and semiquantitative RT-PCR, respectively. Histological grading of rejection were determined.

RESULTS: Allogeneic whole liver grafts showed no features of rejection at day 4 after transplantation. In contrast, allogeneic partial liver grafts demonstrated moderate to severe rejection at day 4 after transplantation. DCs derived from allogeneic partial liver graft 4 d after transplantation exhibited typical morphological characteristics of DC after 4 d’ culture in the presence of GM-CSF. DCs from allogeneic whole liver graft 0 h and 4 d after transplantation did not exhibit typical morphological characteristics of DC until after 10 d’ culture in the presence of GM-CSF. After 10 d’ propagation in vitro, DCs derived from allogeneic whole liver graft exhibited features of immature DC, with absence of CD40, CD80 and CD86 surface expression, and low levels of IL-12 proteins (IL-12 p35 and IL-12 p40) and IL-12 receptor (IL-12Rβ₁ and IL-12Rβ₂) mRNA, whereas DCs from allogeneic partial liver graft 4 d after transplantation displayed features of mature DC, with high levels of CD40, CD80 and CD86 surface expression, and as a consequence, higher expression of IL-12 proteins (IL-12 p35 and IL-12 p40) and IL-12 receptors (IL-12Rβ₁ and IL-12Rβ₂) mRNA than those of DCs both from partial liver graft 0 h and whole liver graft 4 d after transplantation (P < 0.001) was observed.

CONCLUSION: DCs derived from allogeneic partial liver graft undergoing acute rejection display features of mature DC.

Human deficiencies in type-1 cytokine receptors reveal the essential role of type-1 cytokines in immunity to intracellular bacteria

Human genetic factors play an important role in determining the outcome of infections caused by intracellular pathogens, including mycobacteria and salmonellae (reviewed in 1). The genetic elements involved and the mechanisms by which these control disease-susceptibility versus resistance, however, remain incompletely characterized. Recent studies on patients with idiopathic, severe infections due to poorly pathogenic mycobacteria and salmonellae have revealed that many of these patients are unable to produce or respond to IFN-gamma. This inability results from causative, deleterious genetic mutations in either one of five different genes in the type-1 cytokine cascade, encoding IL-12p40, IL-12Rbeta1, IFN-gammaR1, IFN-gammaR2 or Stat-1. The mutational events can lead to complete or partial deficiency, and are mostly autosomal recessive but can be dominant negative as well. The immunological, clinical and histopathological phenotypes resulting from the ten groups of genetic type-1 cytokine (receptor) deficiency distinguished thus far differ significantly. These findings are summarized, discussed and placed in a broader context in relation to protective immune mechanisms and disease susceptibility.

Localized JAK/STAT signaling is required for oriented cell rearrangement in a tubular epithelium

Rearrangement of cells constrained within an epithelium is a key process that contributes to tubular morphogenesis. We show that activation in a gradient of the highly conserved JAK/STAT pathway is essential for orienting the cell rearrangement that drives elongation of a genetically tractable model. Using loss-of-function and gain-of-function experiments, we show that the components of the pathway from ligand to the activated transcriptional regulator STAT are required for cell rearrangement in the Drosophila embryonic hindgut. The difference in effect between localized expression of ligand (Unpaired) and dominant active JAK (Hopscotch) demonstrates that the ligand plays a cell non-autonomous role in hindgut cell rearrangement. Taken together with the appearance of STAT92E in a gradient in the hindgut epithelium, these results support a model in which an anteroposterior gradient of ligand results in a gradient of activated STAT. These results provide the first example in which JAK/STAT signaling plays a required role in orienting cell rearrangement that elongates an epithelium.

Severe Mycobacterium bovis BCG infections in a large series of novel IL-12 receptor beta1 deficient patients and evidence for the existence of partial IL-12 receptor beta1 deficiency

Cell mediated immunity plays a critical role in human host defence against intracellular bacteria. In patients with unusual, severe infections caused by poorly pathogenic species of mycobacteria and salmonellae, genetic deficiencies have been identified in key genes in the type-1 cytokine pathway, especially in IFNGR1 and IL12RB1. Here, we analyzed 11 patients originating from Turkey and suffering from unusual Mycobacterium bovis Bacille Calmette-Guerin infections following vaccination, and found that most patients (n=8) are deficient in IL-12Rbeta1 expression and function. No defects were found in patients' IFN-gammaR or IL-18R. In addition, a first patient suffering from partial IL-12Rbeta1 deficiency is described. This patient presented with an intermediate cellular and immunological phenotype: a consistent, low response to IL-12 was found, which could be further augmented by IL-18. Despite a lack of cell surface IL-12Rbeta1 expression, normal levels of intracellular IL-12Rbeta1 protein were detectable, which was not seen in the other, completely IL-12Rbeta1 deficient patients examined. Moreover, this patient had a relatively mild clinical phenotype and was the only individual with a single homozygous amino acid substitution in IL-12Rbeta1 (C198R). Collectively, our findings indicate that idiopathic, unusually severe infections due to M. bovis BCG can be caused by complete as well as partial IL-12Rbeta1 deficiency.

Expression and characterization of recombinant canine IL-13 receptor alpha2 protein and its biological activity in vitro

Our previous study showed that recombinant canine IL-13 (rcaIL-13) stimulated production of allergen-specific IgE in vitro by peripheral blood mononuclear cells (PBMC) from flea allergen-sensitized dogs. This has also been demonstrated using human IL-13 (huIL-13) and PBMC isolated from human allergy patients. The stimulatory activity of rcaIL-13 was specifically inhibited by a fusion protein of the extracellular domain of canine IL-13Ralpha2 and the Fc fragment of canine IgG heavy chain (rcaIL-13Ralpha2-Fc). In this communication, we report the construction and expression of a non-fused recombinant extracellular domain of canine IL-13Ralpha2 (rcaIL-13Ralpha2) in an E. coli expression system. The E. coli expressed rcaIL-13Ralpha2 was isolated in inclusion bodies, then solubilized in buffer containing denaturants and reducing agents. After refolding and purification, the biological activity of rcaIL-13Ralpha2 was found in the monomer fraction resulting from gel filtration and ion exchange chromatographies. Biological activity of purified rcaIL-13Ralpha2 was demonstrated by the specific inhibition of rcaIL-13 activity in a TF-1 cell proliferation assay. Additionally, rcaIL-13Ralpha2 was found to be active in neutralizing rcaIL-13 induced upregulation of IgE mRNA levels in PBMCs of "high IgE" dogs, which have been bred to exhibit a predisposition for high IgE production and are used as a model for allergic asthma. The data confirm our previous report that the regulatory effects of IL-13 on IgE production in canine PBMCs are similar to those reported in humans. Thus, allergic dogs, such as the "high IgE" producing dogs, may be excellent models for research on IgE-mediated diseases in humans.

Interleukin-10 receptor expression in human dental pulp cells in response to lipopolysaccharide from Prevotella intermedia

Interleukin-10 receptor (IL-10R) expression in human, dental pulp, fibroblast cultures was investigated by using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. After exposure to lipopolysaccharide (LPS) from Prevotella intermedia, the IL-10R mRNA levels increased after 4 h, peaked at 7 h, and dropped back to the unstimulated level at 24 h. Maximal production of the IL-10R protein in dental pulp fibroblast cultures was detected by Western blot analysis after 12 h of LPS stimulation. In contrast, the human skin fibroblast (SF-MA) and human monocyte (U937) cell lines expressed IL-10R mRNA. Anti-CD14 antibodies inhibited P. intermedia LPS-induced IL-10R mRNA expression. These results indicate that P. intermedia LPS induces IL-10R gene expression in human, dental pulp fibroblasts in vitro.

Impaired accumulation and function of memory CD4 T cells in human IL-12 receptor beta 1 deficiency

Defects in IL-12 production or IL-12 responsiveness result in a vulnerability to infection with non-viral intracellular organisms, but the immunological mechanisms responsible for this susceptibility remain poorly understood. We present an immunological analysis of a patient with disseminated Salmonella enteritidis and a homozygous splice acceptor mutation in the IL-12Rbeta1-chain gene. This mutation resulted in the absence of IL-12Rbeta1 protein on PBMC and an inability of T cells to specifically bind IL-12 or produce IFN-gamma in response to either IL-12 or IL-23. The accumulation of memory (CD45R0(high)) CD4 T cells that were CCR7(high) (putative central memory cells) was normal or increased for age. Central memory CD4 T cells of the patient and age-matched controls were similar in having a low to undetectable capacity to produce IFN-gamma after polyclonal stimulation. In contrast, the patient had a substantial decrease in the number of CCR7(neg/dull) CD45R0(high) memory CD4 T cells (putative effector memory cells), and these differed from control cells in having a minimal ability to produce IFN-gamma after polyclonal stimulation. Importantly, tetanus toxoid-specific IFN-gamma production by PBMC from the patient was also significantly reduced compared with that in age-matched controls, indicating that signaling via the IL-12Rbeta1-chain is generally necessary for the in vivo accumulation of human memory CD4 T cells with Th1 function. These results are also consistent with a model in which the IL-12Rbeta1 subunit is necessary for the conversion of central memory CD4 T cells into effector memory cells.

Interleukin-2 inhibits proliferation of HPV-associated tumor cells and halts tumor growth in vivo

Previous studies have shown inhibition of cervical cancer cell growth by treatment with high concentrations of IL-2. In the present study, we evaluated the in vitro and in vivo effects of recombinant human IL-2 on HPV-associated tumor cells (3T3-16). Treatment of 3T3-16 cells with rhIL-2 for 72 h inhibited cell growth in a dose-dependent manner and this effect was evidenced at nanomolar concentrations. These tumor cells expressed mRNA for beta and gamma subunits of the IL-2 receptor, which are required for signal transduction. In experiments to explore the effect of IL-2 on the growth of the HPV-associated tumor, mice received rhIL-2 through different routes: (i) intraperitoneal; (ii) subcutaneous, at the tumor inoculation site; or (iii) subcutaneous, distant from the tumor inoculation site. An effective antitumor response was observed only in those animals that received IL-2 at the tumor site (P<0.01). These results indicate the potential adequacy of therapeutic strategies based on local administration of rhIL-2 for cervical carcinoma, not only based on the ability of this cytokine to stimulate cellular-mediated immunity but also because of its direct effects on tumor cells.

IL-13 receptor-targeted cytotoxin cancer therapy leads to complete eradication of tumors with the aid of phagocytic cells in nude mice model of human cancer

Tumor-directed therapeutic approaches require unique or overexpressed specific Ag or receptor as a target to achieve selective tumor killing. However, heterogeneous expression of these targets on tumor cells limits the efficacy of this form of therapy. In this study, we forced abundant expression of IL-13Ralpha2 chain by plasmid-mediated gene transfer in head and neck, as well as prostate tumors to provide a potential target. This was followed by successfully treating xenograft tumor-bearing nude mice with IL-13R-directed cytotoxin (IL13-PE38QQR). Although we did not observe an indirect cytotoxic bystander effect conveyed to nontransduced tumor cells in vitro, our approach in vivo led to a complete regression of established tumors transfected with IL-13Ralpha2 chain in most animals. We found that the tumor eradication was achieved in part by infiltration of macrophages and NK cells, assessed by immunohistochemistry. Moreover, head and neck tumors xenografted in macrophage-depleted nude mice were less sensitive to the antitumor effect of IL-13 cytotoxin. Because we did not observe vector-related toxicity in any vital organs, our novel combination strategy of gene transfer of IL-13Ralpha2 chain and receptor-directed cytotoxin therapy may be a useful approach for the treatment of localized cancer.

The roles of IL-12 in providing a third signal for clonal expansion of naive CD8 T cells

Stimulation of an effective in vitro or in vivo response by naive CD8 T cells requires three signals: TCR engagement, costimulation/IL-2, and a third signal that can be provided by IL-12. In addition to being required for acquisition of cytolytic function, IL-12 is required for optimal IL-2-dependent proliferation and clonal expansion. In experiments examining in vitro stimulation of naive CD8 T cells, IL-12 is shown to stimulate expression of the IL-2R alpha-chain (CD25) to much higher levels than are reached in response to just TCR and costimulation and/or IL-2. In addition, high CD25 expression is substantially prolonged in the presence of IL-12. As a consequence, the cells proliferate more effectively in response to low levels of IL-2. Examination of adoptively transferred TCR transgenic CD8 T cells responding to peptide Ag confirmed that IL-12 up-regulates CD25 in vivo, even when B7-mediated costimulation is largely blocked. TCR- and IL-2-dependent proliferation of CD8 T cells from mice deficient in CD25 was also found to increase in the presence of IL-12, indicating that CD25 up-regulation is not the only mechanism by which IL-12 increases clonal expansion of the cells. IL-2 and IL-12 both act to increase expression of both CD25 and the IL-12R, thus providing positive cross-regulation of receptor expression. These results suggest that when cross-priming dendritic cells present class I/Ag and costimulatory ligands, and produce IL-12, naive CD8 T cells will begin to produce IL-2 and both receptors will be optimally up-regulated to insure that an effective response is generated.

Nitric oxide preferentially induces type 1 T cell differentiation by selectively up-regulating IL-12 receptor beta 2 expression via cGMP

Nitric oxide plays an important role in immune regulation. We have shown that although high concentrations of NO generally were immune-suppressive, low concentrations of NO selectively enhanced the differentiation of T helper (Th)1 cells but not Th2 cells. This finding provided an explanation for the crucial role of NO in defense against intracellular pathogens. However, the mechanism for the selective induction of Th1 cells was unknown. We report here that at low concentrations, NO activates soluble guanylyl cyclase, leading to the up-regulation of cGMP, which selectively induces the expression of IL-12 receptor beta2 but has no effect on IL-4 receptor. Because IL-12 and IL-4 are the key cytokines for induction of Th1 and Th2 cells, respectively, these results, therefore, provide the mechanism for the selective action of NO on T cell subset differentiation. Furthermore, this selectivity also applies to CD8+ cytotoxic and human T cells and, thus, demonstrates the general implication of this observation in immune regulation. Our results also provide an example of the regulation of cytokine receptor expression by NO. The selectivity of such action via cGMP suggests that it is amenable to therapeutic intervention.

Decreased expression of membrane IL-5 receptor alpha on human eosinophils: I. Loss of membrane IL-5 receptor alpha on airway eosinophils and increased soluble IL-5 receptor alpha in the airway after allergen challenge

IL-5 is a key cytokine for eosinophil maturation, recruitment, activation, and possibly the development of inflammation in asthma. High concentrations of IL-5 are present in the airway after Ag challenge, but the responsiveness of airway eosinophils to IL-5 is not well characterized. The objectives of this study were to establish, following airway Ag challenge: 1) the expression of membrane (m)IL-5Ralpha on bronchoalveolar lavage (BAL) eosinophils; 2) the responsiveness of these cells to exogenous IL-5; and 3) the presence of soluble (s)IL-5Ralpha in BAL fluid. To accomplish these goals, blood and BAL eosinophils were obtained from atopic subjects 48 h after segmental bronchoprovocation with Ag. There was a striking reduction in mIL-5Ralpha on airway eosinophils compared with circulating cells. Furthermore, sIL-5Ralpha concentrations were elevated in BAL fluid, but steady state levels of sIL-5Ralpha mRNA were not increased in BAL compared with blood eosinophils. Finally, BAL eosinophils were refractory to IL-5 for ex vivo degranulation, suggesting that the reduction in mIL-5Ralpha on BAL eosinophils may regulate IL-5-mediated eosinophil functions. Together, the loss of mIL-5Ralpha, the presence of sIL-5Ralpha, and the blunted functional response (degranulation) of eosinophils to IL-5 suggest that when eosinophils are recruited to the airway, regulation of their functions becomes IL-5 independent. These observations provide a potential explanation for the inability of anti-IL-5 therapy to suppress airway hyperresponsiveness to inhaled Ag, despite a reduction in eosinophil recruitment.

Present status on the genetic studies of asthma

Asthma, one of the most common chronic diseases, is a complex and heterogeneous disorder. The results of genome screens for asthma-related traits in 11 different populations identified at least 18 regions of the genome that probably house asthma/atopy genes. The most consistently replicated regions are on chromosomes 2q, 5q, 6p, 12q and 13q. Positional cloning projects are ongoing in laboratories around the world to identify the asthma susceptibility loci in these regions. In addition, many candidate genes have been associated with asthma phenotypes, such as the genes in the IL-4/IL-13 pathway.

Arginine butyrate increases the cytotoxicity of DAB(389)IL-2 in leukemia and lymphoma cells by upregulation of IL-2Rbeta gene

DAB(389)IL-2 (ONTAK) is a fusion protein consisting of the ADP-ribosyltransferase and membrane translocating domains of native diphtheria toxin and the full-length sequence for interleukin-2 (IL-2) gene. In vitro data demonstrates that DAB(389)IL-2 is cytotoxic to cells expressing the high affinity IL-2 receptor (IL-2R). In Phases I and II clinical trials of patients whose tumor cells express a component of the IL-2R, the response rates were 18% for B-cell non-Hodgkin lymphoma (NHL) and 30% for cutaneous T-cell lymphoma (CTCL). In this study, we examined the effects of arginine butyrate on IL-2R expression and susceptibility of leukemia cells to intoxication by DAB(389)IL-2. We demonstrate that the p75 subunit of the IL-2R (IL-2Rbeta) is upregulated in the presence of low concentrations of arginine butyrate (0.06mM) which had no direct growth inhibitory effect on the cells. To explore mechanisms of this upregulation, we examined the effect of 0.06mM arginine butyrate on relevant transcriptional elements and on histone deacetylase and found activation of cAMP response element (CRE) but not NFAT or NFKB, as well as inhibition of histone deacetylase (HDAC). Our results suggest that the effects of physiologically achievable concentrations of butyrate on IL-2R expression could be exploited to enhance the susceptibility of intermediate and low-affinity IL-2R expressing leukemia cells to DAB(389)IL-2.

CD30-governor of memory T cells?

CD30 is well recognized as a marker expressed by a heterogeneous group of lymphomas and in several immune and autoimmune disorders. However, the function of CD30 in theses diseases or in the normal immune response has remained unclear. Studying gene expression patterns induced by stimulating CD30 signals on a large granular lymphoma cell line, YT, with an agonistic anti-CD30 antibody, we found that CD30 signals affected proapoptotic and antiapoptotic genes, regulated cytotoxicity, and controlled molecules regulating T cell traffic. Creating CD30-L deficient mice and studying CD8 CTL activation and memory responses, it was observed that the absence of CD30-L resulted in diminished primary clonal expansion of CD8 cells. In addition the absence of CD30-L abolished clonal contraction after primary expansion and interfered with secondary expansion upon boosting. The studies suggest that CD30 regulates CD8 CTL function and survival during memory responses and is important for clonal contraction.

The Drosophila cytokine receptor Domeless controls border cell migration and epithelial polarization during oogenesis

In mammals, the JAK/STAT (Janus Kinase/Signal Transducer and Activator of Transcription) signaling pathway is activated in response to cytokines and growth factors to control blood cell development, proliferation and cell determination. In Drosophila, a conserved JAK/STAT signaling pathway controls segmentation in embryos, as well as blood cell development and other processes in larvae and adults. During embryogenesis, transduction of the Unpaired [Upd; also known as Outstretched (Os)] ligand through the JAK/STAT pathway requires Domeless, a putative membrane protein with distant homology to vertebrate type I cytokine receptors. We have isolated domeless (dome) in a screen to identify genes essential in epithelial morphogenesis during oogenesis. The level of dome activity is critical for proper border cell migration and is controlled in part through a negative feedback loop. In addition to its essential role in border cells, we show that dome is required in the germarium for the polarization of follicle cells during encapsulation of germline cells. In this process, dome controls the expression of the apical determinant Crumbs. In contrast to the ligand Upd, whose expression is limited to a pair of polar cells at both ends of the egg chamber, dome is expressed in all germline and follicle cells. However, the Dome protein is specifically localized at apicolateral membranes and undergoes ligand-dependent internalization in the follicle cells. dome mutations interact genetically with JAK/STAT pathway genes in border cell migration and abolish the nuclear translocation of Stat92E in vivo. We also show that dome functions downstream of upd and that both the extracellular and intracellular domains of Dome are required for JAK/STAT signaling. Altogether, our data indicate that Dome is an essential receptor molecule for Upd and JAK/STAT signaling during oogenesis.

Roles of inhibitory interneurons in the cerebellar cortex

The roles of inhibitory interneurons in the cerebellar cortex were investigated. First, Golgi cells were specifically eliminated in transgenic mice in which Golgi cells expressed human interleukin-2 receptor alpha subunit (IL2Ralpha). Injection of exotoxin coupled to anti-IL2Ralpha antibody in the cerebellum of the transgenic mouse eliminated Golgi cells and abolished GABA and synaptic inhibition in the granular layer. After elimination of Golgi cells, acute severe ataxia and subsequent mild motor discoordination were observed. In the latter chronic phase, NMDA receptor-mediated synaptic response was reduced in granule cells. Our findings indicate that elimination of GABAergic inhibition in the granular layer caused overexcitation of granule cells resulting in severe ataxia, and then NMDA receptors in granule cells were downregulated, compensating for the reduction of GABAergic inhibition and improving motor control. In the second part, we report on the regulation mechanism of synaptic plasticity at inhibitory synapses on Purkinje cells (PCs). Inhibitory synaptic transmission on a PC is potentiated after repetitive PC depolarization. This synaptic plasticity (rebound potentiation, RP) was suppressed when a presynaptic neuron was activated during the PC depolarization. This synaptic regulation is unique in the sense that the homosynaptic activity suppresses the induction of synaptic plasticity. The mechanism of how presynaptic activity suppresses RP was examined. GABA released from the presynaptic terminal activated not only GABA(A) receptor but also GABA(B) receptor. The latter was coupled to Gi/o proteins, which downregulated adenylyl cyclase reducing cAMP and inactivated cAMP-dependent protein kinase (PKA). Downregulation of PKA suppressed RP induction.