Influenza is a major cause of morbidity and mortality in immunosuppressed persons, and vaccination often confers insufficient protection. IL-28B, a member of the interferon (IFN)-λ family, has variable expression due to single nucleotide polymorphisms (SNPs). While type-I IFNs are well known to modulate adaptive immunity, the impact of IL-28B on B- and T-cell vaccine responses is unclear. Here we demonstrate that the presence of the IL-28B TG/GG genotype (rs8099917, minor-allele) was associated with increased seroconversion following influenza vaccination (OR 1.99 p = 0.038). Also, influenza A (H1N1)-stimulated T- and B-cells from minor-allele carriers showed increased IL-4 production (4-fold) and HLA-DR expression, respectively. In vitro, recombinant IL-28B increased Th1-cytokines (e.g. IFN-γ), and suppressed Th2-cytokines (e.g. IL-4, IL-5, and IL-13), H1N1-stimulated B-cell proliferation (reduced 70%), and IgG-production (reduced>70%). Since IL-28B inhibited B-cell responses, we designed antagonistic peptides to block the IL-28 receptor α-subunit (IL28RA). In vitro, these peptides significantly suppressed binding of IFN-λs to IL28RA, increased H1N1-stimulated B-cell activation and IgG-production in samples from healthy volunteers (2-fold) and from transplant patients previously unresponsive to vaccination (1.4-fold). Together, these findings identify IL-28B as a key regulator of the Th1/Th2 balance during influenza vaccination. Blockade of IL28RA offers a novel strategy to augment vaccine responses.

We postulate that IL-28B may act as a key regulator of ISG expression during primary CMV infection. IL-28B SNPs may be associated with higher antiviral ISG expression, which results in better replication control.

In this study, we differentiated the human hepatoma cell line Huh7.5 by supplementing tissue culture media with human serum (HS) and examined the production of hepatitis C virus (HCV) by these cells. We compared the standard tissue culture protocol, using media supplemented with 10% fetal bovine serum (FBS), to media supplemented with 2% HS. Cells cultured in HS undergo rapid growth arrest, have a hepatocyte-like morphology, and increase the expression of hepatocyte differentiation markers. In addition, expression of cell adhesion proteins claudin-1, occludin, and e-cadherin are also increased. The lipid droplet content of these cells is highly increased, as are key lipid metabolism regulators liver X receptor alpha, peroxisome proliferator-activated receptor (PPAR)-a, and PPAR-c. Very-low-density lipoprotein secretion, which is absent in FBSgrown cells, is restored in Huh7.5 cells that are cultured in HS. All these factors have been implicated in the life cycle of HCV. We show that viral production of Japanese fulminant hepatitis type 1 increases 1,000-fold when cells are grown in HS, compared to standard FBS culture conditions. The virus produced under these conditions is associated with apolipoprotein B, has a lower density, higher specific infectivity, and has a longer half-life than virus produced in media supplemented with FBS. Conclusion: We describe a convenient, cost-effective method to produce hepatocyte-like cells, which produce large amounts of virus that more closely resemble HCV present in serum of infected patients. (HEPATOLOGY 2013;58:1907-1917 H epatitis C virus (HCV) is an enveloped, positive-strand RNA virus of the family of Flaviviridae that causes acute and chronic hepatitis. HCV can cause cirrhosis, hepatocellular carcinoma, and steatosis in infected individuals.Replicon systems, both subgenomic and full length, and the Japanese fulminant hepatitis type 1 (JFH-1) tissue culture infection models have yielded important insight into the HCV life cycle. Most of these models make use of HuH-7 or HuH-7-derived cells, such as Huh7.5. HuH-7 or HuH-7-derived cells have many advantages for the in vitro study of HCV: they are readily available and rapidly dividing, and therefore enable large-scale experiments. However, these systems do not necessarily accurately represent events that occur during a natural HCV infection in vivo, because hepatocytes are normally nondividing and fully differentiated. To circumvent this, dimethyl sulfoxide

Objective. The response to and toxicity of methotrexate (MTX) are unpredictable in patients with juvenile idiopathic arthritis (JIA). Intracellular polyglutamation of MTX, assessed by measuring concentrations of MTX polyglutamates (MTXGlu), has been demonstrated to be a promising predictor of drug response. Therefore, this study was aimed at investigating the genetic predictors of MTXGlu variability and associations between MTXGlu and drug response in JIA.Methods. The study was designed as a singlecenter cross-sectional analysis of patients with JIA who were receiving stable doses of MTX at a tertiary care children's hospital. After informed consent was obtained from the 104 patients with JIA, blood was withdrawn during routine MTX-screening laboratory testing. Clinical data were collected by chart review. Genotyping for 34 single-nucleotide polymorphisms (SNPs) in 18 genes within the MTX metabolic pathway was performed. An ion-pair chromatographic procedure with mass spectrometric detection was used to measure MTXGlu 1-7 .Results. Analysis and genotyping of MTXGlu was completed in the 104 patients. K-means clustering resulted in 3 distinct patterns of MTX polyglutamation. Cluster 1 had low red blood cell (RBC) MTXGlu concentrations, cluster 2 had moderately high RBC MTXGlu 1 ؉ 2 concentrations, and cluster 3 had high concentrations of MTXGlu, specifically MTXGlu 3-5 . SNPs in the purine and pyrimidine synthesis pathways, as well as the adenosine pathway, were significantly associated with cluster subtype. The cluster with high concentrations of MTXGlu 3-5 was associated with elevated liver enzyme levels on liver function tests (LFTs), and there were higher concentrations of MTXGlu 3-5 in children who reported gastrointestinal side effects and had abnormal findings on LFTs. No association was noted between MTXGlu and active arthritis.Conclusion. MTXGlu remains a potentially useful tool for determining outcomes in patients with JIA being treated with MTX. The genetic predictors of MTXGlu variability may also contribute to a better understanding of the intracellular biotransformation of MTX in these patients.The response to methotrexate (MTX) in patients with juvenile idiopathic arthritis (JIA) is variable, with no identified predictors of response or toxicity (1-3). The mechanism of action of the drug is complex and incompletely understood. However, over the past several decades, we have gained increasing knowledge regarding specific sites of MTX action within the cellular folate cycle. Due to its inhibitory effect on several target enzymes, we know that MTX disrupts the folate cycle, which results in decreased production of DNA precursors, disruption of methyl-dependent reactions, and accumulation of adenosine, the latter of which has antiinflammatory properties (4-6).

Safety is the foremost issue in all human cell therapies, but human induced pluripotent stem cells (iPSCs) currently lack a useful safety indicator. Studies in chimeric mice have demonstrated that certain lines of iPSCs are tumorigenic; however a similar screen has not been developed for human iPSCs. Here, we show that in vitro cartilage tissue engineering is an excellent tool for screening human iPSC lines for tumorigenic potential. Although all human embryonic stem cells (ESCs) and most iPSC lines tested formed cartilage safely, certain human iPSCs displayed a pro-oncogenic state, as indicated by the presence of secretory tumors during cartilage differentiation in vitro. We observed five abnormal iPSC clones amoungst 21 lines derived from five different reprogramming methods using three cellular origins. We conclude that in vitro cartilage tissue engineering is a useful approach to identify abnormal human iPSC lines.