A physical and regulatory map of host-influenza interactions reveals pathways in H1N1 infection.

During the course of a viral infection, viral proteins interact with an array of host proteins and pathways. Here, we present a systematic strategy to elucidate the dynamic interactions between H1N1 influenza and its human host. A combination of yeast two-hybrid analysis and genome-wide expression profiling implicated hundreds of human factors in mediating viral-host interactions. These factors were then examined functionally through depletion analyses in primary lung cells. The resulting data point to potential roles for some unanticipated host and viral proteins in viral infection and the host response, including a network of RNA-binding proteins, components of WNT signaling, and viral polymerase subunits. This multilayered approach provides a comprehensive and unbiased physical and regulatory model of influenza-host interactions and demonstrates a general strategy for uncovering complex host-pathogen relationships.

The effects of levothyroxine combined with methimazole on the clinical efficacy of hyperthyroidism treatment.

To investigate the effects of levothyroxine combined with methimazole on the clinical efficacy of hyperthyroidism treatment. A total of 102 patients with hyperthyroidism admitted to our hospital from January 2018 to June 2020 were selected and randomly assigned into the combination group (levothyroxine combined with methimazole) and the control group (methimazole treatment alone). 3 months after treatment, the two groups were compared with regard to clinical efficacy, changes in ultrasound findings, the thyroid hormones, and serum indexes and the adverse reactions rate. The combination group (98.04%) outperformed the control group (86.27%) in total effective rate, and the overall efficacy garnered the similar result. After treatment, the combination group showed advantages in thyroid hormone level, serum index level, thyroid volume, superior thyroid artery diameter, and maximum blood flow rate when compared with those of the control group (P<0.05). As for the adverse reactions rate, the combination group was superior to the control group (3.92%vs15.69%) (P<0.05). Levothyroxine combined with methimazole promotes the clinical efficacy of hyperthyroidism treating, reduces thyroid volume and the diameter of superior thyroid artery, enhances the patient's thyroid function and serum index, with higher safety profile.

Association of plasma free fatty acids levels with the presence and severity of coronary and carotid atherosclerotic plaque in patients with type 2 diabetes mellitus.

BACKGROUND: Previous studies have suggested that patients with diabetes mellitus (DM) have higher prevalence of atherosclerotic cardiovascular disease (ASCVD), and plasma levels of free fatty acids (FFAs) are a useful marker for predicting ASCVD. We hypothesized that FFAs could predict both coronary and carotid lesions in an individual with type 2 DM (T2DM). The present study, hence, was to investigate the relation of plasma FFA level to the presence and severity of coronary and carotid atherosclerosis in patients with T2DM. METHODS: Three hundred and two consecutive individuals with T2DM who have received carotid ultrasonography and coronary angiography due to chest pain were enrolled in this study. Plasma FFAs were measured using an automatic biochemistry analyzer. Coronary and carotid severity was evaluated by Gensini score and Crouse score respectively. Subsequently, the relation of FFA levels to the presence and severity of coronary artery disease (CAD) and carotid atherosclerotic plaque (CAP) in whole individuals were also assessed. RESULTS: Increased plasma FFA levels were found in the groups either CAD or CAP compared to those without. Patients with higher level of FFAs had a higher CAD (89.9%) and elevated prevalence of CAP (69.7%). And also, patients with higher level of FFAs had a higher Gensini and Crouse scores. Multivariate regression analysis showed that FFA levels were independently associated with the presence of CAD and CAP (OR = 1.83, 95%CI: 1.27-2.65, P = 0.001; OR = 1.62, 95%CI: 1.22-2.14, P = 0.001, respectively). The area under the curve (AUC) was 0.68 and 0.65 for predicting the presence of CAD and CAP in patients with DM respectively. CONCLUSIONS: The present study firstly indicated that elevated FFA levels appeared associated with both the presence and severity of CAD and CAP in patients with T2DM, suggesting that plasma FFA levels may be a useful biomarker for improving management of patients with T2DM.

High-intensity focused ultrasound ablation induced apoptosis in human hepatocellular carcinoma.

BACKGROUND/AIMS: To evaluate the effect of high-intensity ultrasound (HIFU) ablation on human hepatocellular carcinoma tissues and apoptotic proteins (bcl-2 and p-53). METHODOLOGY: Patients with hepatocellular carcinoma at stage B were treated with HIFU ablation. Levels of bcl-2 and p53 protein and the apoptosis rate were evaluated both in the pre-treatment and post-treatment tissue specimens using immunochemistry and TUNEL methods, respectively. RESULTS: After HIFU ablation, p53 protein levels were significantly increased around the coagulation necrosis area, whereas, the level of bcl-2 was significantly decreased. More apoptosis cells were found post ablation compared with those in the pretreatment tissues. Additionally, no significant correlation was found between p53/bcl-2 levels and apoptotic index. CONCLUSIONS: HIFU ablation may exert promote the apoptosis of hepatocellular carcinoma cells and the effect has a closely association with the change of p53 and bcl-2 expression.

Heat-fluid-solid coupling heat transfer analysis and parameter optimization in walnut drying device based on finite element method.

The moisture content of freshly picked walnuts is very high. In order to facilitate storage and transportation, it needs to be dried to prevent mildew. In this study, the pre-drying simulation and experimental study were carried out on the walnut drying equipment made by the research group to determine the optimal drying parameters. The effects of different inlet temperatures (353K, 373K, 393K), drying wind speeds (1.1 m/s, 1.4 m/s, 1.7 m/s) and drying time (30min, 45min, 60min) on the temperature and velocity fields of fluid and walnuts in the drying device were investigated by using the orthogonal test method of three factors and three levels. FLUENT software was used to simulate the drying process of open walnuts under hot air heating, and the distribution of fluid temperature field and velocity field in the drying device and the temperature change law of walnuts were obtained. The results show that when the inlet temperature is 393K, the inlet velocity is 1.7 m/s, and the drying time is 45min, the temperature field distribution of fluid and walnut in the drying device is the best and the change is the most uniform. In addition, the temperature change of the simulation results is consistent with the test results through experiments, which verifies the reliability of the simulation results. In order to more accurately simulate the change law of temperature and humidity transfer in hot air drying of walnuts, the walnut was modeled as a sphere consisting of three layers: walnut shell, air gap and walnut kernel. The reliability of the parameters was verified by surface response analysis. Taking inlet temperature, velocity and drying time as influencing factors and temperature change rate as evaluation index, the determination coefficient of regression model was R2 = 0.9966, and the correction determination coefficient Adj. R2 = 0.9922, indicating three influences. This study provides a theoretical basis for determining the optimum operating parameters of open walnut pre-drying, and has application value for walnut food processing.

CD47 antibody blockade suppresses microglia-dependent phagocytosis and monocyte transition to macrophages, impairing recovery in EAE.

Experimental autoimmune encephalomyelitis (EAE) is a well-characterized animal model of multiple sclerosis. During the early phase of EAE, infiltrating monocytes and monocyte-derived macrophages contribute to T cell recruitment, especially CD4+ T cells, into the CNS, resulting in neuronal demyelination; however, in later stages, they promote remyelination and recovery by removal of myelin debris by phagocytosis. Signal regulatory protein α and CD47 are abundantly expressed in the CNS, and deletion of either molecule is protective in myelin oligodendrocyte glycoprotein-induced EAE because of failed effector T cell expansion and trafficking. Here we report that treatment with the function blocking CD47 Ab Miap410 substantially reduced the infiltration of pathogenic immune cells but impaired recovery from paresis. The underlying mechanism was by blocking the emergence of CD11chiMHCIIhi microglia at peak disease that expressed receptors for phagocytosis, scavenging, and lipid catabolism, which mediated clearance of myelin debris and the transition of monocytes to macrophages in the CNS. In the recovery phase of EAE, Miap410 Ab-treated mice had worsening paresis with sustained inflammation and limited remyelination as compared with control Ab-treated mice. In summary, Ab blockade of CD47 impaired resolution of CNS inflammation, thus worsening EAE.

Atherogenic dyslipidaemia and cardiovascular events in patients with diabetes or pre-diabetes and stable coronary artery disease: a prospective, cohort study.

OBJECTIVE: The aim of the study was to investigate the impacts of triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) dyslipidaemia on prognosis in coronary artery disease (CAD) patients with different glucose metabolism status. DESIGN: An observational cohort study. SETTING/PARTICIPANTS: A total of 3057 patients with stable CAD were consecutively enrolled and divided into three groups according to different glucose metabolism status. Atherogenic dyslipidaemia (AD) was defined as TG ≥1.7 mmol/L and HDL-C <1.0 mmol/L for men or <1.3 mmol/L for women. The patients were further classified into six subgroups by status of AD. All subjects were followed up for the cardiovascular events (CVEs). PRIMARY OUTCOME MEASURES: The primary endpoints were cardiovascular mortality, non-fatal myocardial infarction and non-fatal stroke. RESULTS: During a median follow-up of 6.1 years, 308 (10.1%) CVEs occurred. No significant difference in the occurrence of CVEs was observed between normal glucose regulation (NGR) and pre-diabetes (pre-DM) groups (HR: 1.25, 95% CI 0.89 to 1.76) while DM group presented 1.45-fold higher risk of CVEs (HR: 1.45, 95% CI 1.02 to 2.05). When the participants were categorised according to combined status of two parameters, the cardiovascular risk was significantly elevated in pre-DM or DM plus AD group compared with the NGR plus non-AD group (HR: 1.76, 95% CI 1.10 to 2.80 and HR: 1.87, 95% CI 1.17 to 2.98). CONCLUSIONS: The present study suggested that the presence of AD might affect the prognosis in patients with DM or pre-DM and stable CAD.

Epstein-Barr virus LF2: an antagonist to type I interferon.

Upon viral infection, the major defense mounted by the host immune system is activation of the interferon (IFN)-mediated antiviral pathway, which is mediated by IFN regulatory factors (IRFs). In order to complete their life cycle, viruses must modulate host IFN-mediated immune responses. Despite its association with significant human health problems, activities of Epstein-Barr virus (EBV), a human tumor-inducing herpesvirus, to evade host IFN-mediated innate immunity have not been well characterized. To search for EBV genes that block IFN signal transduction, we carried out a screening of EBV open reading frames for their abilities to block IFN-alpha/beta-mediated luciferase expression upon Sendai virus infection. This screening demonstrates that EBV LF2 tegument protein specifically interacts with the central inhibitory association domain of IRF7, and this interaction leads to inhibition of the dimerization of IRF7, which suppresses IFN-alpha production and IFN-mediated immunity. This demonstrates a novel immune evasion mechanism of EBV LF2 in blocking cellular IRF7-mediated innate immunity.

Effects of knockout of long-chain non-coding RNA LSINCT5 on proliferation, apoptosis, epithelial-mesenchymal transition, and p38MAPK pathway of pancreatic cancer PANC-1 cells.

BACKGROUND: Our study aims to investigate the effects of the knockout of long non-coding RNA LSINCT5 (lncRNA LSINCT5) on the proliferation, apoptosis, epithelial-mesenchymal transition (EMT), and p38MAPK pathway of pancreatic cancer PANC-1 cells, to provide a basis for searching for the therapeutic targets of pancreatic cancer. METHODS: The laboratory findings and clinical data of 21 patients with pancreatic cancer were retrospectively collected, and the survival rates of patients with high or low lncRNA LSINCT5 expressions were analyzed. PANC-1 cells were randomly divided into the control group, shRNA-NC group, and sh-LSINCT5 group, and the constructed sh-LSINCT5 and shRNA-NC vectors were transfected into the corresponding cells. The successful interference of lncRNA LSINCT5 was confirmed by reverse transcription polymerase chain reaction (RT-PCR). CCK-8 and spherogenesis assay detected the proliferation and spherogenesis of PANC-1 cells. The apoptosis rate was evaluated by flow cytometry. Western blotting was used to identify the expressions of KI67, PCNA, SOX2, OCT4, E-cadherin, N-cadherin, and Vimentin and the activation of Caspase-3 and Caspase-9. RESULTS: The survival rate of patients with low lncRNA LSINCT5 expression was higher than that of patients with high lncRNA LSINCT5 expression. Compared with the control group, lncRNA LSINCT5 knockout significantly down-regulated the expressions of KI67, PCNA, SOX2, OCT4, cleaved Caspase-3, cleaved Caspase-9, N-cadherin and Vimentin (all P<0.05) and significantly decreased the cell proliferation, sphere size, and number of spheres in PANC-1 cells (all P<0.05); meanwhile, it up-regulated the protein expression of E-cadherin (P<0.05), along with the significantly increased number of apoptotic PANC-1 cells (P<0.05). In addition, compared with the control group, the level of p38 phosphorylation significantly dropped after lncRNA LSINCT5 knockout (P<0.05). CONCLUSIONS: Knockout of lncRNA LSINCT5 can inhibit the proliferation, EMT, and p38MAPK pathway of PANC-1 cells and meanwhile promote the apoptosis of PANC-1 cells. Therefore, lncRNA LSINCT5 may be a promising therapeutic target for pancreatic cancer.

Purification and Identification of Antioxidant Alcalase-Derived Peptides from Sheep Plasma Proteins.

In this study, sheep plasma was submitted to Alcalase-hydrolysis and peptides with better antioxidant properties measured through both the ferric-reducing antioxidant power (FRAP) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability assays were isolated and identified. After hydrolysate ultrafiltration and semi-preparative reverse-phase high-performance liquid chromatography, nine fractions (F1-F9) were obtained, with the two first (F1 and F2) showing the greatest antioxidant potential. These two fractions were further separated by the AKTA purifier system to generate four (F1-1-F1-4) and five (F2-1-F2-5) fractions, respectively, with two of them (F1-2 and F2-1) exhibiting appreciable FRAP activity and DPPH radical scavenging ability. Using liquid chromatography-tandem mass spectrometry, three antioxidant peptides were identified. From their amino acid sequences (QTALVELLK, SLHTLFGDELCK, and MPCTEDYLSLILNR), which include amino acids that have been previously reported as key contributors to the peptide antioxidant properties, it can be maintained that they come mainly from serum albumin. These results suggested that the sheep plasma protein can be considered as a good source of antioxidant peptides and bring forth new possibilities for the utilization of animal blood by-products.

Effects of Drying Methods and Ash Contents on Heat-Induced Gelation of Porcine Plasma Protein Powder.

Porcine blood plasma is a rich source of proteins with high nutritional and functional properties, which can be used as a food ingredient. The plasma is usually processed into powders in applications. In the present study, the effects of drying methods and ash contents on heat-induced gelation of plasma protein powder were investigated. The drying methods had a significant impact on the gel properties of the plasma powder heat-induced gels. The hardness and elasticity of the gels by freeze-dried and spray-dried plasma powders were lower than that of the liquid plasma (p < 0.05). The microstructures of dehydrated plasma were denser and the holes were smaller. The secondary structure of the gels from the spray-dried plasma protein powders exhibited more α-helixes and less ß-turns than that from the freeze-dried powder and liquid plasma. The thermostability of dehydrated plasma powder was found to have decreased compared to the liquid plasma. Compared with the gels obtained from the high ash content plasma protein powders, the gel from the 6% ash content plasma powder had the highest water-holding capacity and had the lowest hardness and elasticity. However, the secondary structure and microstructures of the heat-induced gels were not affected by the ash contents in the plasma powders. These findings show that the gel properties of plasma protein powder can be finely affected by drying methods and ash contents.

Comparative profiling of sarcoplasmic phosphoproteins in ovine muscle with different color stability.

The phosphorylation of sarcoplasmic proteins in postmortem muscles was investigated in relationship to color stability in the present study. Although no difference was observed in the global phosphorylation level of sarcoplasmic proteins, difference was determined in the phosphorylation levels of individual protein bands from muscles with different color stability. Correlation analysis and liquid chromatography - tandem mass spectrometry (LC-MS/MS) identification of phosphoproteins showed that most of the color stability-related proteins were glycolytic enzymes. Interestingly, the phosphorylation level of myoglobin was inversely related to meat color stability. As the phosphorylation of myoglobin increased, color stability based on a∗ value decreased and metMb content increased. In summary, the study revealed that protein phosphorylation might play a role in the regulation of meat color stability probably by regulating glycolysis and the redox stability of myoglobin, which might be affected by the phosphorylation of myoglobin.

Triglyceride glucose index for predicting cardiovascular outcomes in patients with coronary artery disease.

BACKGROUND: Triglyceride glucose (TyG) index is a novel marker for metabolic disorders and recently it has been reported to be associated with cardiovascular disease (CVD) risk in apparently healthy individuals. However, the prognostic value of TyG index in patients with stable coronary artery disease (CAD) is not determined. METHODS: We conducted a nested case-control study among 3,745 patients with stable CAD. Patients were followed up for 11,235 person-years. The cardiovascular events (CVEs) were defined as all-cause death, non-fatal myocardial infarction (MI), stroke and post-discharge revascularization [percutaneous coronary intervention (PCI) coronary artery bypass grafting (CABG)]. In total, 290 (7.7%) patients with CVEs and 1,450 controls were matched according to age, gender, previous history of PCI or CABG and the duration of follow-up. TyG index was calculated as formula: ln[fasting triglycerides (mg/dL) × fasting plasma glucose (mg/dL)/2]. RESULTS: Multivariable Cox proportional hazards models revealed that TyG index was positively associated with CVEs risk (hazard ratio: 1.364, 95% confidence interval: 1.100-1.691, P=0.005). The Kaplan-Meier analysis indicated that patients within the highest quartile of TyG index presented the lowest event-free survival (P=0.029). Moreover, a 1-standard deviation (SD) increment in TyG index was associated with 23.2% [hazard ratio (HR): 1.232, 95% confidence interval (95% CI): 1.084-1.401] higher risk of CVEs, which was superior to other triglyceride or glycemic related markers. CONCLUSIONS: The present study, firstly, showed that TyG index was positively associated with future CVEs, suggesting that TyG may be a useful marker for predicting clinical outcomes in patients with CAD.

[The effects of nuclear factor-kappaB decoy oligonucleotides on dextran sulphate sodium-induced colitis: experiment with mice].

OBJECTIVE: To investigate the effects of nuclear factor-kappaB (NF-kappaB) decoy oligonucleotide (ODN) on dextran sulphate sodium (DSS)-induced colitis. METHODS: Nine female BABL/C mice underwent infusion of 0.15 ml normal saline into the distant colon and used as controls (Group 1). Twenty-seven female BABL/C mice were made into DSS-induced colitis models and then randomly divided into 3 groups: Group 2 (underwent infusion of 0.15 ml normal saline into the distant colon), Group 3 (infused with NF-kappaB decoy ODN 25 nmol solved in 0.15 ml), and Group 4 (infused with NF-kappaB scrambled decoy ODN 25 nmol solved in 0.15 ml). Disease active index (DAI) was observed every day. Nine days later the mice were killed and their colons were taken out to undergo histological examination. The tumor necrosis factor (TNF)-alpha level of the colon mucosa was measured by enzyme linked immunosorbent assay (ELISA). NF-kappaB expression was determined by immunohistochemical staining. The distribution of NF-kappaB decoy ODN was investigated by confocal laser microscopy. RESULTS: (1) The DAI scores, histological scores and TNF-a level in the colon mucosa of Groups 2 - 4 were all significantly higher than those of Group 1 (all P < 0.05). The DAI scores, histological scores and TNF-a level in the colon mucosa of Group 3 were all significantly lower than those of Groups 2 and 4 (all P < 0.01). (2) In the tissue sections NF-kappaB p65 was positive mainly in the nucleus in the 3 DSS-treated groups without significant differences among these 3 groups, and was mainly positive in the cytoplasm in the control group. (3) Confocal laser microscopy showed that NF-kappaB decoy ODN could be ingested efficiently into the mucosa and submucous layer of colon. (4) There were no significant differences in the liver function, kidney function, and blood glucose among all groups. CONCLUSION: NF-kappaB pathway is associated with the pathogenesis of DSS-induced colitis which is very similar to human UC. Blockade of NF-kappaB pathway by NF-kappaB decoy ODN shows protective effect on the mice with DSS-induced colitis.

Early enteral nutrition improves intestinal immune barrier in a rat model of severe acute pancreatitis.

BACKGROUND: The aim of the present study was to investigate the role of early enteral nutrition (EEN) in the intestinal immune barrier in severe acute pancreatitis (SAP), and to explore its potential mechanisms. METHODS: Sixty rats were randomly assigned to three groups: sham-operated group (SO group, n = 20), SAP group receiving EEN (SAP + EEN group, n = 20), and SAP group receiving total parental nutrition (SAP + TPN group, n = 20). SAP was induced by infusion of sodium taurocholate. Rats were killed 5 days after nutritional support. The pathological damage of the intestine was determined using HE staining. The expression of MAdCAM-1, CD4+ , and CD8+ in Peyer's lymph nodes of the distal ilium was examined by immunohistochemistry. Serum levels of endotoxin and bacterial translocation were determined. RESULTS: The survival rate in the SAP + TPN (50%) and SAP + EEN (75%) groups was significantly lower than in the SO group (100%) (P < 0.05). The survival rate in the SAP + EEN group was significantly higher than in the SAP + TPN group (P < 0.05). The expression of MAdCAM-1, CD4+ and CD8+ in the intestine was decreased in SAP rats. EEN significantly increased the expression of MAdCAM-1, CD4+ and CD8+ compared with TPN, accompanied by a decrease in the serum levels of endotoxin and bacterial translocation. CONCLUSIONS: Early enteral nutrition improves intestinal immune barrier, thus reducing bacterial and endotoxin translocation and improving the survival rate in SAP rats.

[Unilateral external fixation assisted with closed reduction and interlocking intramedullary nail fixation for the treatment of comminuted fracture of femoral shaft].

OBJECTIVE: To introduce the use of single arm external fixation assisted reduction and closed complex intramedullary nail fixation for the treatment of femoral shaft fracture operation method and to study its effects. METHODS: From June 2008 to October 2012, 24 patients with femoral shaft fractures were treated with unilateral external fixation assisted by closed reduction, interlocking intramedullary nail fixation. Among the patients, 19 patients were male and 5 patients were female, ranging in aged from 20 to 68 years,with an average of 45.6 years old. The fracture was caused by traffic accidents in 14 cases, by falling in 6 cases, by heavy bruising in 4 cases. Admission diagnosis was femoral shaft fracture. Operation was performed after traction from tibial tubercle for about 1 week. RESULTS: All the patients were followed up, and the duration ranged from 6 to 24 months, with a mean of 16.2 months. The X-ray showed fracture healing time ranging from 11 to 17 weeks, with an average of 13.8 weeks. All fractures healed without nails broken or close joint dysfunction. According to femoral shaft efficacy evaluation standards, 23 patients got an excellent result, 1 good. CONCLUSION: Unilateral fixator assisted closed reduction and interlocking intramedullary nail fixation for the treatment of femoral shaft fracture has following advantages: less trauma, simple operation, effective reduction, high rate of fracture healing, and low complication rate.

[Clinical application of blocking screws and rooting technique in the treatment of distal tibial fracture with interlocking intramedullary nail].

OBJECTIVE: To introduce the clinical method of blocking screws and rooting technique in the treatment of distal tibial fracture with interlocking intramedullary nails. METHODS: From June 2006 to March 2011, 26 patients with distal tibial fracture were treated with interlocking intramedullary nails using blocking screws and rooting technique, included 18 males and 8 females with an average age of 46.2 years old ranging from 24 to 64 years. According to AO classification: 10 cases of type A1, 4 cases of type A2, 8 cases of type B1, 4 cases of type B2. The average distance of the fractures end to the ankle joint was 85 mm ranging from 55 to 125 mm, the mean time between injured and operation was 4.5 days. The patients were evaluated with pain, range of motion, walking. RESULTS: All cases were followed-up for 6 to 22 months (averaged 15 months). According to Iowa ankle joint grading system,the score was improved from preoperative (66.8 +/- 8.2) to postoperative (94.6 +/- 4.8). All fractures had united, and got satisfactory reduction and stable fixation with no complications had happen such as breakage of screw. CONCLUSION: Fixation with interlocking intramedullary nail using blocking screws and rooting technique in treating distal tibial fracture, is a safe and effective technique for the improvement of stability.

Compatibility of the gH homologues of Epstein-Barr virus and related lymphocryptoviruses.

Glycoprotein gH, together with its chaperone gL and a third glycoprotein gB, is essential for cell-cell fusion and virus-cell fusion mediated by herpesviruses. Epstein-Barr virus (EBV), the prototype human lymphocryptovirus, requires a fourth glycoprotein gp42 to support fusion with B cells in addition to epithelial cells. Two other lymphocryptoviruses, the rhesus lymphocryptovirus (Rh-LCV) and the common marmoset lymphocryptovirus (CalHV3), have been sequenced in their entirety and each has a gp42 homologue. Combinations of proteins from EBV, Rh-LCV and CalHV3 were able to mediate fusion of epithelial cells, but, even when complexed with EBV gp42, only Rh-LCV and not CalHV3 proteins were able to mediate fusion with human B cells. CalHV3 gL was also unable to function effectively as a chaperone for EBV or Rh-LCV gH. The Rh-LCV gH homologue supported more fusion than EBV gH with an epithelial cell and supported the highest levels of fusion with a B cell. Chimeric constructs made from Rh-LCV gH and EBV gH that have 85.4 % sequence identity should prove useful for mapping the regions of gH that are of importance to fusion as a whole and to B-cell fusion in particular.

Point mutations in EBV gH that abrogate or differentially affect B cell and epithelial cell fusion.

Cell fusion mediated by Epstein-Barr virus requires three conserved glycoproteins, gB and gHgL, but activation is cell type specific. B cell fusion requires interaction between MHC class II and a fourth virus glycoprotein, gp42, which complexes non-covalently with gHgL. Epithelial cell fusion requires interaction between gHgL and a novel epithelial cell coreceptor and is blocked by excess gp42. We show here that gp42 interacts directly with gH and that point mutations in the region of gH recognized by an antibody that differentially inhibits epithelial and B cell fusion significantly impact both the core fusion machinery and cell-specific events. Substitution of alanine for glycine at residue 594 completely abrogates fusion with either B cells or epithelial cells. Substitution of alanine for glutamic acid at residue 595 reduces fusion with epithelial cells, greatly enhances fusion with B cells and allows low levels of B cell fusion even in the absence of gL.

Inhibition of interferon regulatory factor 7 (IRF7)-mediated interferon signal transduction by the Kaposi's sarcoma-associated herpesvirus viral IRF homolog vIRF3.

Upon viral infection, the major defense mounted by the host immune system is activation of the interferon (IFN)-mediated antiviral pathway that is mediated by IFN regulatory factors (IRFs). In order to complete their life cycle, viruses must modulate the host IFN-mediated immune response. Kaposi's sarcoma-associated herpesvirus (KSHV), a human tumor-inducing herpesvirus, has developed a unique mechanism for antagonizing cellular IFN-mediated antiviral activity by incorporating viral homologs of the cellular IRFs, called vIRFs. Here, we report a novel immune evasion mechanism of KSHV vIRF3 to block cellular IRF7-mediated innate immunity in response to viral infection. KSHV vIRF3 specifically interacts with either the DNA binding domain or the central IRF association domain of IRF7, and this interaction leads to the inhibition of IRF7 DNA binding activity and, therefore, suppression of alpha interferon (IFN-alpha) production and IFN-mediated immunity. Remarkably, the central 40 amino acids of vIRF3, containing the double alpha helix motifs, are sufficient not only for binding to IRF7, but also for inhibiting IRF7 DNA binding activity. Consequently, the expression of the double alpha helix motif-containing peptide effectively suppresses IRF7-mediated IFN-alpha production. This demonstrates a remarkably efficient means of viral avoidance of host antiviral activity.