Amounts Of Interferon Research Articles

Human Conventional and Plasmacytoid Dendritic Cells Differ in Their Ability to Respond to Saccharomyces cerevisiae.

Saccharomyces cerevisiae is a commensal yeast colonizer of mucosal surfaces and an emerging opportunistic pathogen in the mucosa and bloodstream. The role of S. cerevisiae has been largely characterized in peripheral blood mononuclear cells and monocyte-derived dendritic cells, where yeast cells induce the production of inflammatory cytokines through the interaction with mannose receptors, chitin receptors, DC SIGN, and dectin1. However, the response of blood-circulating dendritic cells (DCs) to S. cerevisiae has never been investigated. Among blood DCs, conventional DCs (cDCs) are producers of inflammatory cytokines, while plasmacytoid DCs (pDCs) are a specialized population producing a large amount of interferon (IFN)-α, which is involved in the antiviral immune response. Here we report that both human DC subsets are able to sense S. cerevisiae. In particular, cDCs produce interleukin (IL)-6, express activation markers, and promotes T helper 17 cell polarization in response to yeasts, behaving similarly to monocyte-derived DCs as previously described. Interestingly, pDCs, not cDCs, sense fungal nucleic acids, leading to the generation of P1-pDCs (PD-L1+CD80–), a pDC subset characterized by the production of IFN-α and the induction of a Th profile producing IL-10. These results highlight a novel role of pDCs in response to S. cerevisiae that could be important for the regulation of the host microbiota–immune system balance and of anti-fungal immune response.

Hormone therapy affecting interferon defense in children with infectious mononucleosis

23 children diagnosed with acute infectious mononucleosis were hospitalized and examined after a short prednisolone treatment course. Related interferon status during infection was compared with that in 38 patients with acute infectious mononucleosis receiving no hormone therapy. Interferon status was investigated by Ershov method, allowing to estimate amount of interferon in the blood serum samples or patient blood cell culture by assessing interferon biological activity. Along with measuring IFNα or IFNγ biological activity, their level was quantified by using enzyme immunoassay. Immunological examination conducted on the next day after the end of hormone therapy revealed sharply decreased potential of patient blood cells to produce both IFNα and IFNγ. The multiplicity of IFNα and IFNγ titer reduction in various patients varied by 4–5 and 3–4-fold, respectively. The concentration of IFNα, determined by ELISA, decreased by 4–6-fold, whereas for IFNγ — by 1.5–2-fold. A follow-up examination 1 month after discharge from the clinic showed that mean IFNα titer in children aged 3–6 years and treated with prednisolone was significantly reduced compared to the baseline, whereas most patients receiving no hormone therapy had normal IFNα production. The change in the level of IFNα 1 month after hormone therapy in 7–14-year age group was similar. IFNγ production quickly recovered, and 1 month after discharge from the clinic, its concentration in culture supernatants from patients reached 10–15 ng/ml, exceeding normal values more than twice. The biological activity of IFNγ in these culture supernatants was significantly higher than those immediately after hormone therapy, whereas in 3–6-year-old group of patients it was also higher than baseline level. These results can serve as a laboratory justification for including recombinant IFNα-2b drugs in the therapy of such patients, presumably immediately after the end of hormone course. Overall, laboratory justified administration of interferon preparations seems to be necessary to determine optimal timepoint for applying such drugs to increase effectiveness for achieving a durable patient recovery.

Endosomal TLR3 co-receptor CLEC18A enhances host immune response to viral infection

Human C-type lectin member 18A (CLEC18A) is ubiquitously expressed in human, and highest expression levels are found in human myeloid cells and liver. In contrast, mouse CLEC18A (mCLEC18A) is only expressed in brain, kidney and heart. However, the biological functions of CLEC18A are still unclear. We have shown that a single amino acid change (S339 →R339) in CTLD domain has profound effect in their binding to polysaccharides and house dust mite allergens. In this study, we further demonstrate that CLEC18A and its mutant CLEC18A(S339R) associate with TLR3 in endosome and bind poly (I:C) specifically. Compared to TLR3 alone, binding affinity to poly (I:C) is further increased in TLR3-CLEC18A and TLR3-CLEC18A(S339R) complexes. Moreover, CLEC18A and CLEC18A(S339R) enhance the production of type I and type III interferons (IFNs), but not proinflammatory cytokines, in response to poly (I:C) or H5N1 influenza A virus (IAV) infection. Compared to wild type (WT) mice, ROSA-CLEC18A and ROSA-CLEC18A(S339R) mice generate higher amounts of interferons and are more resistant to H5N1 IAV infection. Thus, CLEC18A is a TLR3 co-receptor, and may contribute to the differential immune responses to poly (I:C) and IAV infection between human and mouse.

MZB1 enables efficient interferon \u03b1 secretion in stimulated plasmacytoid dendritic cells

MZB1 is an endoplasmic reticulum (ER)-resident protein that plays an important role in the humoral immune response by enhancing the interaction of the μ immunoglobulin (Ig) heavy chain with the chaperone GRP94 and by augmenting the secretion of IgM. Here, we show that MZB1 is also expressed in plasmacytoid dendritic cells (pDCs). Mzb1−/− pDCs have a defect in the secretion of interferon (IFN) α upon Toll-like receptor (TLR) 9 stimulation and a reduced ability to enhance B cell differentiation towards plasma cells. Mzb1−/− pDCs do not properly expand the ER upon TLR9 stimulation, which may be accounted for by an impaired activation of ATF6, a regulator of the unfolded protein response (UPR). Pharmacological inhibition of ATF6 cleavage in stimulated wild type pDCs mimics the diminished IFNα secretion by Mzb1−/− pDCs. Thus, MZB1 enables pDCs to secrete high amounts of IFNα by mitigating ER stress via the ATF6-mediated UPR.

PD-L2+ wound zone macrophage-like cells display M1/M2-mixed activation and restrain the effector Th1 responses.

Depending on the microenvironment conditions, macrophages display phenotypic and functional heterogeneity. This study characterized the programmed cell death-ligand 2 (PD-L2)-expressing macrophage-like cells drained from surgical wound zones, and investigated their influence on helper T (Th) cell responses. Although all CD14+ myeloid cells possessed macrophage-like features, CD206+ and CD163+ cells constituted a specific subpopulation with high PD-L2 expression. There was a modest correlation between the PD-L2 levels on CD206+ macrophages and the amount of interferon (IFN)-γ in the drainage fluid. The adhesion-independent macrophages simultaneously presented both classically-activated M1 and alternatively-activated M2 characteristics. CD206+ and PD-L2+ cells were identified with high granularity and size, expressed arginase-1 and costimulatory molecules, had enhanced phagocytic activity and produced reactive oxygen species. The genes associated with macrophage differentiation (MERTK, AXL and TYRO3) were also upregulated. These cells provided costimulation to Th cells; yet, when PD-L2 was blocked, T-cell proliferation and IFNγ production were enhanced. Under defined conditions devoid of activation stimuli and matrix adhesion, ex vivo-generated monocyte-derived macrophages displayed limited capacity to stimulate T cells. Upon exposure to IFNγ, they significantly upregulated programmed death 1 ligands, especially PD-L2. These cells did not completely abrogate T-cell differentiation; however, PD-L2 checkpoint blockade restored Th1 proliferation and secretion of interleukin-2, tumor necrosis factor-α and IFNγ. In conclusion, upregulation of PD-L2 on the wound zone macrophages may constitute a negative feedback loop that restrains the Th1 effector responses and avoids exacerbation of inflammation during tissue healing.

Nasal epithelial cells to assess in vitro immune responses to respiratory virus infection in pregnant women with asthma

Respiratory virus-induced asthma exacerbations occur frequently during pregnancy and are associated with adverse outcomes for mother and child. Primary nasal epithelial cells (pNECs) provide a useful method to study immune responses in pregnancy. pNECs were obtained by nasal brushings from pregnant and non-pregnant women with and without asthma. pNECS were infected in vitro with major group Rhinovirus 43 (RV43) and seasonal influenza (H3N2). Following infection, pNECs showed measurable quantities of interferon (IFN)-λ, IL-1β, IL-8, IP-10 and MIP1-α. pNECs provide a safe and effective method for studying respiratory epithelial cell responses during pregnancy.

Long Noncoding RNA GM16343 Promotes IL-36β to Regulate Tumor Microenvironment by CD8+T cells.

Objective:To investigate the effect of long noncoding RNA GM16343 on interleukin 36β promotion of CD8+T cells in tumor microenvironment regulation.Methods:The differentially expressed long noncoding RNA in interleukin 36β-stimulated mouse CD8+T cells was screened by gene chip technology, and the significant differentially expressed long noncoding RNAs were verified by real-time polymerase chain reaction. The lentiviral vector that overexpresses or knockdown GM16343 was constructed, transfected into CD8+T cells, and stimulated with interleukin 36β, and the amount of interferon γ secreted was detected by enzyme-linked immunosorbent assay. A mouse subcutaneous xenograft model that stably express interleukin 36β was established, and the tumor size and mouse survival time were observed by stimulation with CD8+T cells overexpression or knockdown of GM16343.Results:A total of 12 long noncoding RNAs with significant differences were screened by gene chip analysis. Real-time polymerase chain reaction showed that the difference in GM16343 was larger, and the difference between the groups was observed to be the most significant. Compared to control group, CD8+T cells overexpressing GM16343 increased the secretion of interferon γ, and the tumor diameter of the mice after stimulation showed significant reduction, and the survival time showed significant prolongation. Compared to control group, the CD8+T cells after GM16343 were knocked down. The interferon γ secretion was decreased, and no significant change in tumor diameter and survival time was observed.Conclusion:Interleukin 36β may enhance antitumor immune response of CD8+T cells by regulating GM16343.

Different effects of the immunostimulatory drug Stimforte on infections of hepatitis C virus and herpes simplex virus type 1.

Stimforte, an immune response-stimulating preparation, is active with respect to hepatitis C virus (HCV) and herpes simplex virus type I (HSV-1). The effects of Stimforte in animals infected with either HCV or HSV-1 are fundamentally different. In mice with acute herpes virus infection, Stimforte administration leads to a higher activity of natural killer cells and cytotoxic lymphocytes, and the amount of interferon (IFN) λ grows. In mice infected with HCV, Stimforte administration results in a significant increase in IFN-β but not IFN-λ in blood and affected organs. Stimforte has been found to affect directly HCV reproduction that causes the infected cell death, but it does not affect HSV-1 reproduction in the Vero cells (V).

Murine Cytomegalovirus Disrupts Splenic Dendritic Cell Subsets via Type I Interferon-Dependent and -Independent Mechanisms.

Dendritic cells (DC) are well-known modulators of immunity. This heterogeneous population is composed of defined subsets that exhibit functional specialization and are critical in initiating responses to pathogens. As such, many infectious agents employ strategies to disrupt DC functioning in attempts to evade the immune system. In some instances, this manifests as an outright loss of these cells. Previous work has suggested that, in the absence of an efficient natural killer (NK) cell response, murine cytomegalovirus (MCMV) induces large amounts of interferon (IFN)-I. This heightened IFN-I response is thought to contribute to conventional DC (cDC) loss and delayed development of T cell immunity. However, the precise role of IFN-I in such cDC loss remains unclear. We investigated the effects of licensed NK cells and IFN-I signaling on splenic cDC subsets during MCMV infection and found that a licensed NK cell response partially protects cDC numbers, but does not prevent increases in serum IFN-I. This suggested that high residual IFN-I could contribute to cDC loss. Therefore, we used multiple strategies to modulate IFN-I signaling during MCMV infection including plasmacytoid DC depletion, IFN-I receptor (IFNAR) blockade, and genetic ablation of IFNAR expression. Interestingly, restriction of IFN-I signals did not substantially preserve either CD8+ or CD4+ DC total numbers, but resulted in significant retention and/or accumulation of the splenic CD8− CD4− [double negative (DN)] subset. However, the DN DC effect manifested in a DC-extrinsic manner since IFNAR-deficient cells were not preferentially retained over their IFNAR wild-type counterparts in a mixed-chimera setting. Our results show that IFN-I signaling is not responsible for overt cDC toxicity in the setting of acute MCMV infection and emphasize that additional mechanisms contribute to DC loss and require exploration.

Effects of the Janus Kinase Inhibitor CP-690550 (Tofacitinib) in a Rat Model of Oxazolone-Induced Chronic Dermatitis

The effect of CP-690550 (tofacitinib), a new Janus kinase (JAK) inhibitor, was evaluated in chronic allergic dermatitis. Allergic contact dermatitis was induced in rat ears by repeated application of oxazolone. This dermatitis was accompanied by sustained ear swelling and marked epidermal hyperplasia. In the induced ear, a lot of inflammatory cells infiltrated into the dermis site and the amounts of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-22 were elevated. Orally administered CP-690550 significantly suppressed ear swelling as well as epidermal thickening, and the effect at 10 mg/kg was comparable to that of cyclosporin A and etanercept. These results suggest a great potential of CP-690550, a JAK inhibitor, as a treatment for chronic dermatitis featuring epidermal hyperplasia (in the pathogenesis of which IFN-γ, TNF-α and IL-22 play a role) such as psoriasis and chronic atopic dermatitis.

Refractoriness of interferon-beta signaling through NOD1 pathway in mouse respiratory epithelial cells using the anticancer xanthone compound

To explore the possibility that nucleotide oligomerization domain 1 (NOD1) pathway involved in refractoriness of interferon-β signaling in mouse respiratory epithelial cells induced by the anticancer xanthone compound, 5,6-dimethylxanthenone-4-acetic acid (DMXAA). C10 mouse bronchial epithelial cells were grown in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 2 mmol/L glutamine, 100 units/mL penicillin, 100 g/mL streptomycin. Pathogen-free female BALB/c mice were used to explore the mechanisms of refractoriness of interferon-signaling. Mouse thioglycollate-elicited peritoneal macrophages, bone marrow derived macrophages and bone marrow derived dendritic cells were collected and cultured. The amount of interferon (IFN)-inducible protein-10 (IP10/CXCL10), macrophage chemotactic protein (MCP1/CCL2) and interleukin (IL)-6 secreted by cells activated by DMXAA was quantified using enzyme-linked immunosorbent assay kits according to the instructions of the manufacturers. Total RNA was isolated from cells or nasal epithelium with RNeasy Plus Mini Kit, and cDNA was synthesized. Gene expression was checked using Applied Biosystems StepOne Real-Time Polymerase Chain Reaction System. Transfection of small interfering RNA (siRNA) control, NOD1 duplexed RNA oligonucleotides, and high-mobility group box 1/2/3 (HMGB1/2/3) siRNA was performed using siRNA transfection reagent. DMXAA activates IFN-β pathway with high level of IFN-β dependent antiviral genes including 2', 5'-oligoadenylate synthetase 1 and myxovirus resistance 1 in mouse thioglycollate-elicited peritoneal macrophages, bone marrow derived macrophages and bone marrow derived dendritic cells. Activation of IFN-β by DMXAA involved in NOD1, but not HMGB1/2/3 signal pathway demonstrated by siRNA. NOD1 pathway plays an important role in refractoriness of IFN-β signaling induced by DMXAA in mouse C10 respiratory epithelial cells and BALB/c mice nasal epithelia. These data indicate that DMXAA is not well adapted to the intrinsic properties of IFN-β signaling. Approaches to restore sensitivity of IFN-β signaling by find other xanthone compounds may function similarly, could enhance the efficacy of protection from influenza pneumonia and potentially in other respiratory viral infections. NOD1 pathway may play an important role in refractoriness of IFN-β signaling in mouse respiratory epithelial cells induced by DMXAA.

Human enterovirus 71 (EV71) resisted type I interferon induced antiviral effect

To investigate human enterovirus 71 (EV71) resistance to type I interferon induced antiviral effect. After type I interferons (alpha, beta) were incubated with HeLa cells, recombinant type I herpes simple virus (HSV-1) with green fluorescent protein (GFP) was inoculated onto the HeLa cells. HSV-1 proliferation was observed by GFP expression and PCR. After EV71 was inoculated onto HeLa cells incubated with the same quantity of interferon, proliferation of EV71 were detected by RT-PCR of 2A gene. Recombinant HSV-1 GFP expression and viral DNA replication obviously decreased in HeLa cells incubated with type I interferon (alpha, beta). However, EV71 effectively proliferated in the interferon irritated HeLa cell by RT-PCR. HeLa cell irritated by type I interferon (alpha, beta) produced antiviral substance that inhibits HSV-1 proliferation. EV71 resisted the antiviral substance induced by type I interferon and could significantly replicate in the HeLa cells.

Immune response to a potyvirus with exposed amino groups available for chemical conjugation

BackgroundThe amino terminus of the tobacco etch virus (TEV) capsid protein is located on the external surface of infectious TEV particles, as proposed by previous studies and an in silico model. The epsilon amino groups on the exposed lysine residues are available for chemical conjugation to any given protein, and can thus act as antigen carriers. The availability of amino groups on the surfaces of TEV particles was determined and the immune response to TEV evaluated.ResultsUsing a biotin-tagged molecule that reacts specifically with amino groups, we found that the TEV capsid protein has amino groups on its surface available for coupling to other molecules via crosslinkers. Intraperitoneal TEV was administered to female BALB/c mice, and both their humoral and cellular responses measured. Different IgG isotypes, particularly IgG2a, directed against TEV were induced. In a cell proliferation assay, only spleen cells from vaccinated mice that were stimulated in vitro with TEV showed significant proliferation of CD3+/CD4+ and CD3+/CD8+ subpopulations and secreted significant amounts of interferon γ.ConclusionsTEV has surface amino groups that are available for chemical coupling. TEV induces both humoral and cellular responses when administered alone intraperitoneally to mice. Therefore, TEV should be evaluated as a vaccine adjuvant when chemically coupled to antigens of choice.

Influenza Virus Interferon-Inducing Particle Efficiency Is Reversed in Avian and Mammalian Cells, and Enhanced in Cells Co-Infected with Defective-Interfering Particles

Naturally selected variants of influenza virus encoding truncated NS1 proteins were tested in chickens as candidate live-attenuated influenza vaccines. Their effectiveness correlated with the amount of interferon (IFN) induced in chicken cells. Effective variants induced large amounts of IFN and contained subpopulations with high ratios of defective-interfering particles:IFN-inducing particles (DIP:IFP). Ineffective variants induced less IFN and contained lower ratios of DIP:IFP. Unexpectedly, there was a reversal of phenotypes in mammalian cells. Variants that induced low amounts of IFN and had low DIP:IFP ratios in chicken cells were excellent IFN inducers with high DIP:IFP ratios in mammalian cells, and vice versa. The high DIP:IFP ratios and computer-simulated dynamics of infection suggested that DIP, as an individual particle, did not function as an IFP. The higher efficiency of IFPs in the presence of DIPs was attributed to reduced amounts of newly synthesized viral polymerase known to result from out-competition by defective-interfering RNAs, and the subsequent failure of that polymerase to turn-off cellular mRNA transcription-including IFN-mRNA.

Editorial: Th-1, Th-2 cells and beyond

The proliferation and differentiation of naive CD4 + T helper (Th) cells after antigenic stimulation leads to functionally distinct subsets with different roles in immune response: Th-1 and Th-2 cells. Th- 1 cells produce large quantities of Interferon γ (INF-γ) inducing cell mediated immune responses against intracellular pathogens whereas Th-2 cells produce Interleukin (IL) 4, IL-5 and IL-13 which mediate humoral immunity eliminating extracellular pathogens and parasites. Cite this article (Note that the Hamdan Medical Journal was previously called the Journal of Medical Sciences ): Lukik, ML. Th-1, Th-2 cells and beyond. Journal of Medical Sciences , 2008; 1(1): 5-7. DOI: http://dx.doi.org/10.2174/1996327000801010005

Commonalities Between pDCs and B Cells

Plasmacytoid dendritic cells (pDCs) are a subpopulation of dendritic cells that secrete large amounts of interferons (IFNs) in response to stimuli that activate the Toll-like receptors TLR9 or TLR7. The C-type lectin blood dendritic cell antigen 2 (BDCA2) is uniquely expressed by pDCs, and antibodies that bind BDCA2 inhibit IFN production in response to TLR signaling. Cao et al . found that the abundance of BDCA2 at the cell surface was increased, and signaling was reconstituted in Jurkat cells or a mouse T cell hybridoma cell line when the cells were also transfected to express the γ subunit of the Fcε receptor (FcεR1γ) but not when BDCA2 was coexpressed with the immunoreceptor tyrosine-based activation motif (ITAM) adaptor DAP12 or the related protein DAP10. Analysis of the mRNA and protein abundance of signaling proteins associated with either B cell receptor (BCR) or T cell receptor (TCR) signaling revealed that the signaling cascade of isolated human pDCs most resembled that downstream of BCRs and included the B cell-specific adaptor B cell linker (BLNK, also known as SLP-65 or BASH). Studies with stably transfected human Burkitt lymphoma Namalwa cells (expressing BDCA2, FcεR1γ, and IRF7, a necessary downstream factor) showed that antibody-mediated cross-linking of BDCA2 inhibited IFN production in response to TLR9, TLR7, or TLR8 activation. Thus, BDCA2 appears to use the FcεR1γ as the ITAM adaptor to signal through a BCR-like signaling pathway to mediate inhibition of TLR signaling in pDCs. W. Cao, L. Zhang, D. B. Rosen, L. Bover, G. Watanabe, M. Bao, L. L. Lanier, Y.-J. Liu, BDCA2/FCεRIγ complex signals through a novel BCR-like pathway in human plasmacytoid dendritic cells. PLoS Biol. 5 , e248 (2007). [PubMed]

Silencing of USP18 Potentiates the Antiviral Activity of Interferon Against Hepatitis C Virus Infection

Modulation of the host innate immune response is an attractive means of inhibiting hepatitis C virus (HCV) replication. Having previously determined that expression of the interferon-sensitive gene (ISG)15 protease USP18 is increased in the liver biopsy specimens of patients who do not respond to interferon (IFN)-alfa therapy, we hypothesized that USP18 might hinder the ability of IFN to inhibit HCV replication. The role of USP18 in IFN antiviral activity was examined using an in vitro model of HCV replication that reproduces the full viral life cycle. USP18 was silenced specifically using small inhibitory RNAs (siRNAs), and the dose response of HCV replication and infectious virus production to IFN-alfa was measured. The siRNA knockdown of USP18 in human cells consistently potentiated the ability of IFN to inhibit HCV-RNA replication and infectious virus particle production by a factor of 1-2 log(10). USP18 knockdown also resulted in a number of cellular changes consistent with increased sensitivity to IFN. Decreasing USP18 expression led to increased cellular protein ISGylation in response to exogenous IFN-alfa, prolonged tyrosine phosphorylation of signal transducer and activation of transcription (STAT1), and a general enhancement of IFN-stimulated gene expression. These data suggest that USP18 modulates the anti-HCV type I IFN response, and is a possible therapeutic target for the treatment of HCV infection.

Treatment effects and predictors of a 24‐week course of interferon α‐2b plus ribavirin combination therapy for patients with chronic hepatitis C

In chronic hepatitis C patients with genotype 1b and a high viral load, the sustained virological response (SVR) rate remained as low as 2-3% with conventional interferon (IFN) monotherapy, but improved to more than 20% with IFN alpha-2b plus ribavirin combination therapy. This study examined the therapeutic effects and predictors of this combination therapy. Subjects were 105 patients with chronic hepatitis C (73 males, 32 females) with a median age of 53 years (range 19-70 years). Seventy-two patients had genotype lb and 33 patients had genotype 2 (2a or 2b). Six million units (MU) or 10 MU of IFN alpha-2b was administered by intramuscular injection six times a week for the first 2 weeks, and the same amount of IFN was administered three times a week for the following 22 weeks. During the IFN administration period, 600-800 mg of oral ribavirin was administered daily. Patients who were hepatitis C virus (HCV)-RNA negative 24 weeks after the completion of administration were defined as SVR. The overall SVR rate was 39%; 22.2% for the genotype 1b group and 75.8% for the genotype 2 group, and the difference between the groups was significant (P < 0.0001). Multivariate logistic regression analysis indicated that the factors that contributed to SVR include genotype 2, age (younger than 53 years), and an increase in Th2 measured by flow cytometry before and 4 weeks after start of treatment. The overall SVR rate of IFN alpha-2b plus ribavirin combination therapy for 24 weeks was 39%, and contributing factors for SVR rate include genotype 2, age younger than 53 years and elevated Th2.

Increased Interleukin-6, Interferon-? and Tumour Necrosis Factor-a Production by Tonsillar Mononuclear Cells Stimulated with Alpha-Streptococci in Patients with Pustulosis Palmaris et Plantaris

In vitro cytokine production by tonsillar mononuclear cells under culture conditions with or without lyophilized streptococcal antigens was measured by enzyme-linked immunosorbent assay (ELISA). Under culture conditions without any stimulus, a certain amount of interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, and interleukin (IL)-6, was detected in the supernatant culture fluids from all 29 donors tested and just detectable levels of IL-1alpha and IL-2 were identified in 5 of 12 donors tested; but IL-4 and IL-5 were not detected in any supernatants from 21 donors tested. In 16 patients with pustulosis palmaris et plantaris (PPP), all three alpha-streptococcal antigens from Streptococcus, (S.) sanguis, S. salivarius and S. mitis induced production of IL-6. IFN-gamma and TNF-alpha by tonsillar mononuclear cells at a significant level. However, no significant induction of such cytokines by alpha-streptococcal stimulus was seen in 13 donors without PPP. No significant difference in cytokine production by tonsillar mononuclear cells was seen between the PPP and non-PPP subjects, when stimulated with S. pyogenes, Staphylococcus aureus Cowan I and pokeweed mitogen. In the experiments using tonsillar cell subsets, the cytokine inductions by alpha-streptococcal stimulus were found in monocyte-depleted cells as well as in purified T-cells. but not in B-cells. These data suggest that IL-6, IFN-gamma and TNF-alpha may play an important role in immunological reactions in the tonsils and that a hyper-immune response to some of alpha-streptococcal antigens through increased production of such cytokines by tonsillar mononuclear cells, to which T-cells mainly contribute, may play a key role in the pathogenesis of PPP.

Variables that influence response to different interferon schedules in chronic hepatitis C and predictive models.

In chronic hepatitis C (HCV), standard interferon therapy with 3 MU three times weekly for 6 months is associated with sustained response in about 10-20% of patients while another 10-15% respond only when higher dosages or/and longer periods of treatment are used. Different variables have been described that are associated with sustained response and may also identify patients requiring low- or high-dose regimens. We have analysed a large data base of 442 patients with chronic hepatitis C treated with interferon-alpha to define rates of sustained response in different patient subgroups treated with different schedules. The rate of sustained response was increased with higher dose regimens in most patient categories, defined according to age, pre-treatment liver histology and HCV genotype, while the amount of interferon per one sustained response remained the same or was reduced. The use of higher dose regimen was particularly cost-effective in patients with cirrhosis. Using the same data base, different models of prediction of sustained response in the individual patient were developed and compared. Inclusion of the HCV genotype in these models was found to increase significantly specificity and sensitivity, confirming that this parameter has a major influence on sustained response to interferon therapy in chronic HCV.