Haagmans, B.L.

Dipeptidyl peptidase 4 is a functional receptor for the emerging human coronavirus-EMC (Article)

2013-03-14T00:00:00Z

Most human coronaviruses cause mild upper respiratory tract disease but may be associated with more severe pulmonary disease in immunocompromised individuals. However, SARS coronavirus caused severe lower respiratory disease with nearly 10% mortality and evidence of systemic spread. Recently, another coronavirus (human coronavirus-Erasmus Medical Center (hCoV-EMC)) was identified in patients with severe and sometimes lethal lower respiratory tract infection. Viral genome analysis revealed close relatedness to coronaviruses found in bats. Here we identify dipeptidyl peptidase 4 (DPP4; also known as CD26) as a functional receptor for hCoV-EMC. DPP4 specifically co-purified with the receptor-binding S1 domain of the hCoV-EMC spike protein from lysates of susceptible Huh-7 cells. Antibodies directed against DPP4 inhibited hCoV-EMC infection of primary human bronchial epithelial cells and Huh-7 cells. Expression of human and bat (Pipistrellus pipistrellus) DPP4 in non-susceptible COS-7 cells enabled infection by hCoV-EMC. The use of the evolutionarily conserved DPP4 protein from different species as a functional receptor provides clues about the host range potential of hCoV-EMC. In addition, it will contribute critically to our understanding of the pathogenesis and epidemiology of this emerging human coronavirus, and may facilitate the development of intervention strategies.

Performance evaluation of the new Roche cobas AmpliPrep/cobas TaqMan HCV test, version 2.0, for detection and quantification of hepatitis C virus RNA (Article)

2013-01-01T00:00:00Z

To evaluate the analytical performance and explore the clinical applicability of the new Roche cobas AmpliPrep/cobas TaqMan HCV test, v2.0 (CAP/CTM v2.0), a platform comparison was performed on panels and diagnostic samples with the Roche cobas AmpliPrep/cobas TaqMan HCV test (CAP/CTM v1.0), the Siemens Versant HCV RNA 3.0 branched DNA (bDNA) test, the Abbottm2000 RealTime HCV assay (Realtime assay), and the Siemens Versant HCV transcription-mediated amplification (TMA) test (TMA assay). The analytical performance of the CAP/CTM v2.0 on WHO and Acrometrix panels and clinical specimens of patients infected with HCV genotype 1, 2, 3, 4, 5, or 6 relative to that of the CAP/CTM v1.0 was significantly improved. In a qualitative comparison of the CAP/CTM v2.0 relative to the TMA assay on genotype 1 to 4 samples, the two tests proved to be almost equally sensitive. Response-guided therapy in one of five HCV genotype 4-infected patients previously tested with the CAP/CTM v1.0 would have significantly changed if tested with the CAP/CTM v2.0. In conclusion, the Roche CAP/CTM v2.0 has significantly better performance characteristics than the former CAP/CTM HCV v1.0 and the bDNA assay and performance characteristics comparable to those of the Realtime assay. Copyright

Continuous interferon-α,2b infusion in combination with ribavirin for chronic hepatitis C in treatment-experienced patients (Article)

2012-06-05T00:00:00Z

Background: Sustained virological response (SVR) rates in previous non-responders to pegylated interferon (PEGIFN)-α and ribavirin for chronic HCV remain low (∼10%). We hypothesize that continuous subcutaneous delivery of fully potent interferon (IFN)-α2b via an external pump will lead to stable blood concentrations and thereby prevent subtherapeutic trough levels associated with viral breakthrough. The aims of the study were to assess safety, tolerability and virological response in patients who were previous PEG-IFN-α/ribavirin non-responders. Methods: We randomized 30 HCV genotype 1 (n=24) and genotype 4 (n=6) patients to receive 6, 9 or 12 million units (MU) IFN-α2b daily by continuous subcutaneous administration using an insulin pump (MiniMed® 508; Medtronic Inc., Minneapolis, MN, USA) in combination with ribavirin (1,000-1,600 mg) for 48 weeks. Results: The magnitude of viral decline in the 12 MU group after 4 weeks of treatment was 2.67 log HCV RNA compared with 1.21 and 1.27 log HCV RNA in the 9 and 6 MU groups, respectively (P=0.001). In the intention-to-treat analysis, the SVR rate was 20% (6/30). The perprotocol SVR rate was 25% (6/24), of which four out of six patients in the high-dose arm achieved SVR. Adverse events appeared dose-dependent, were mostly mild-to-moderate and were typical of IFN therapy. Five patients developed irritation and/or abscesses at the injection site. Six serious adverse events were reported in five patients. Conclusions: Continuous delivery of IFN-α2b can induce a strong dose-dependent viral suppression. This could be an effective approach in conjunction with, or as lead-in therapy prior to, treatment with a direct antiviral agent.

Impact of obesity on the bioavailability of peginterferon-α2a and ribavirin and treatment outcome for chronic hepatitis c genotype 2 or 3 (Article)

2012-05-24T00:00:00Z

Background and Aims: Having a body mass index above or equal to 30 kg/m2in conjunction with chronic hepatitis C virus infection is associated with non-responsiveness to treatment with interferon and ribavirin, but details regarding the mechanisms whereby obesity reduces the efficacy of therapy remain unclear. Methods: This study evaluated impact of obesity on outcome as well as interferon and ribavirin concentrations following standard-of-care fixed dosing with peginterferon-α2a 180 μg once weekly and ribavirin 800 mg daily among 303 HCV genotype 2/3-infected patients enrolled in the per-protocol analysis of a recently completed phase III trial (NORDynamIC). Results: Patients with BMI ≥30 kg/m2showed poorer outcome following 24 weeks of therapy (SVR 62% vs. 89% for BMI ≥30 vs. <30; P = 0.006) along with significantly higher steatosis grade (P = 0.002), HOMA-IR (P<0.0001), triglyceride levels (P = 0.0002), and baseline viral load (P = 0.028). Obesity was also significantly associated with lower plasma interferon concentrations on days 3, 7, and 29 (P = 0.02, P = 0.0017, and P<0.0001, respectively) and lower plasma ribavirin concentrations day 29 (P = 0.025), and lower concentration of interferon in turn was associated with a poorer first phase reduction in HCV RNA (P<0.0001). In multivariate analysis, ribavirin concentrations week 12, interferon concentrations day 29, and baseline HCV RNA levels were independent predictors of achieving SVR among patients treated for 24 weeks (n = 140). Conclusions: Reduced bioavailability of interferon and ribavirin along with higher baseline viral load are dominant risk factors for treatment failure in obese patients with chronic hepatitis C.

Metagenomic analysis of the viral flora of pine marten and european badger feces (Article)

2012-02-01T00:00:00Z

A thorough understanding of the diversity of viruses in wildlife provides epidemiological baseline information about potential pathogens. Metagenomic analysis of the enteric viral flora revealed a new anellovirus and bocavirus species in pine martens and a new circovirus-like virus and geminivirus-related DNA virus in European badgers. In addition, sequences with homology to viruses from the families Paramyxo- and Picornaviridae were detected.

IL28B polymorphisms predict reduction of HCV RNA from the first day of therapy in chronic hepatitis C (Article)

2011-11-01T00:00:00Z

Background & Aims: Single nucleotide polymorphisms (SNPs) associated with IL28B influence the outcome of peginterferon-α/ribavirin therapy of chronic hepatitis C virus (HCV) infection. We analyzed the kinetics of HCV RNA during therapy as a function of IL28B SNPs. Methods: IL28B SNPs rs8099917, rs12979860, and rs12980275 were genotyped in 242 HCV treatment-naïve Caucasian patients (67% genotype 1, 28% genotype 2 or 3) receiving peginterferon-α2a (180 μg weekly) and ribavirin (1000-1200 mg daily) with serial HCV-RNA quantifications. Associations between IL28B polymorphisms and early viral kinetics were assessed, accounting for relevant covariates. Results: In the multivariate analyses for genotype 1 patients, the T allele of rs12979860 (Trs12979860) was an independent risk factor for a less pronounced first phase HCV RNA decline (log100.89 IU/ml among T carriers vs. 2.06 among others, adjusted p <0.001) and lower rapid (15% vs. 38%, adjusted p = 0.007) and sustained viral response rates (48% vs. 66%, adjusted p <0.001). In univariate analyses, Trs12979860was also associated with a reduced second phase decline (p = 0.002), but this association was no longer significant after adjustment for the first phase decline (adjusted p = 0.8). In genotype 2/3 patients, Trs12979860was associated with a reduced first phase decline (adjusted p = 0.04), but not with a second phase decline. Conclusions: Polymorphisms in IL28B are strongly associated with the first phase viral decline during peginterferon-α/ ribavirin therapy of chronic HCV infection, irrespective of HCV genotype.

A recombinant influenza a virus expressing domain III of west nile virus induces protective immune responses against influenza and west nile virus (Article)

2011-05-09T00:00:00Z

West Nile virus (WNV) continues to circulate in the USA and forms a threat to the rest of the Western hemisphere. Since methods for the treatment of WNV infections are not available, there is a need for the development of safe and effective vaccines. Here, we describe the construction of a recombinant influenza virus expressing domain III of the WNV glycoprotein E (Flu-NA-DIII) and its evaluation as a WNV vaccine candidate in a mouse model. FLU-NA-DIII-vaccinated mice were protected from severe body weight loss and mortality caused by WNV infection, whereas control mice succumbed to the infection. In addition, it was shown that one subcutaneous immunization with 105TCID50Flu-NA-DIII provided 100% protection against challenge. Adoptive transfer experiments demonstrated that protection was mediated by antibodies and CD4+T cells. Furthermore, mice vaccinated with FLU-NA-DIII developed protective influenza virus-specific antibody titers. It was concluded that this vector system might be an attractive platform for the development of bivalent WNV-influenza vaccines.

Distinct severe acute respiratory syndrome coronavirus-induced acute lung injury pathways in two different nonhuman primate species (Article)

2011-05-01T00:00:00Z

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), caused by influenza A virus H5N1 and severe acute respiratory syndrome coronavirus (SARS-CoV), supposedly depend on activation of the oxidative-stress machinery that is coupled with innate immunity, resulting in a strong proinflammatory host response. Inflammatory cytokines, such as interleukin 1β (IL-1 β), IL-8, and IL-6, play a major role in mediating and amplifying ALI/ARDS by stimulating chemotaxis and activation of neutrophils. To obtain further insight into the pathogenesis of SARS-CoV-associated ALI, we compared SARS-CoV infections in two different nonhuman primate species, cynomolgus macaques and African green monkeys. Viral titers in the upper and lower respiratory tract were not significantly different in SARS-CoV-infected macaques and African green monkeys. Inflammatory cytokines that play a major role in mediating and amplifying ALI/ARDS or have neutrophil chemoattractant activity, such as IL-6, IL-8, CXCL1, and CXCL2, were, however, induced only in macaques. In contrast, other proinflammatory cytokines and chemokines, including osteopontin and CCL3, were upregulated in the lungs of African green monkeys to a significantly greater extent than in macaques. Because African green monkeys developed more severe ALI than macaques, with hyaline membrane formation, some of these differentially expressed proinflammatory genes may be critically involved in development of the observed pathological changes. Induction of distinct proinflammatory genes after SARS-CoV infection in different nonhuman primate species needs to be taken into account when analyzing outcomes of intervention strategies in these species.

Twice weekly PegIFN-Alfa 2a and ribavirin results in superior viral kinetics in HIV/HCV co-infected patients compared to standard therapy (Article)

2011-04-18T00:00:00Z

HCV/HIV co-infected patients have more rapid progression of liver fibrosis and only modest cure rates (sustained virologic responses, SVR) when compared to HCV monoinfected patients. We compared the virologic responses of either twice-weekly peginterferon-alpha-2a 180 μg/wk (for 4 weeks, followed by weekly dosing) or weekly peginterferon-alpha 2a 180 μg/wk, plus weight based ribavirin (1-1.2 g/day), among HIV/HCV co-infected genotype-1 subjects. Patients receiving the investigational dosing had lower levels of HCV RNA at all time points after initiation of therapy. More patients on this arm achieved clinically relevant early virological responses at weeks 1, 2, 4, 12 and 24. The enhanced early virologic response observed with the investigational arm was associated with a higher induction of interferon stimulated genes (ISG). This early double dose regimen also resulted in a rapid normalization of liver enzymes. Twice weekly peginterferon-alpha-2a is associated with more frequent early virological responses with similar safety profiles when compared with standard therapy. Our results, when confirmed in larger randomized clinical trials, may provide a novel therapeutic approach to improve SVR among HIV/HCV co-infected patients, especially African American patients.

Response prediction in chronic hepatitis c by assessment of IP-10 and IL28B-related single nucleotide polymorphisms (Article)

2011-03-04T00:00:00Z

Background: High baseline levels of IP-10 predict a slower first phase decline in HCV RNA and a poor outcome following interferon/ribavirin therapy in patients with chronic hepatitis C. Several recent studies report that single nucleotide polymorphisms (SNPs) adjacent to IL28B predict spontaneous resolution of HCV infection and outcome of treatment among HCV genotype 1 infected patients. Methods and Findings: In the present study, we correlated the occurrence of variants at three such SNPs (rs12979860, rs12980275, and rs8099917) with pretreatment plasma IP-10 and HCV RNA throughout therapy within a phase III treatment trial (HCV-DITTO) involving 253 Caucasian patients. The favorable SNP variants (CC, AA, and TT, respectively) were associated with lower baseline IP-10 (P = 0.02, P = 0.01, P = 0.04) and were less common among HCV genotype 1 infected patients than genotype 2/3 (P<0.0001, P<0.0001, and P = 0.01). Patients carrying favorable SNP genotypes had higher baseline viral load than those carrying unfavorable variants (P = 0.0013, P = 0.029, P = 0.0004 respectively). Among HCV genotype 1 infected carriers of the favorable C, A, or T alleles, IP-10 below 150 pg/mL significantly predicted a more pronounced reduction of HCV RNA from day 0 to 4 (first phase decline), which translated into increased rates of RVR (62%, 53%, and 39%) and SVR (85%, 76%, and 75% respectively) among homozygous carriers with baseline IP-10 below 150 pg/mL. In multivariate analyses of genotype 1-infected patients, baseline IP-10 and C genotype at rs12979860 independently predicted the first phase viral decline and RVR, which in turn independently predicted SVR. Conclusions: Concomitant assessment of pretreatment IP-10 and IL28B-related SNPs augments the prediction of the first phase decline in HCV RNA, RVR, and final therapeutic outcome.

Pharmacodynamics of PEG-IFN-α-2a in HIV/HCV co-infected patients: Implications for treatment outcomes (Article)

2010-09-01T00:00:00Z

Background & Aims: The pharmacokinetics and pharmacodynamics of pegylated-interferon-α-2a (PEG-IFN) have not been described in HCV/HIV co-infected patients. We sought to estimate the pharmacokinetics and pharmacodynamics of PEG-IFN and determine whether these parameters predict treatment outcome. Methods: Twenty-six HCV/human immunodeficiency virus (HIV)-co-infected patients were treated with a 48-week regimen of PEG-IFN (180 μg/week) plus ribavirin (11 mg/kg/day). HCV RNA and PEG-IFN concentrations were obtained from samples collected until week 12. A modeling framework that includes pharmacokinetic and pharmacodynamic parameters was developed. Results: Five patients discontinued treatment. Seven patients achieved a sustained virological response (SVR). PEG-IFN concentrations at day 8 were similar to steady-state levels (p = 0.15) and overall pharmacokinetic parameters were similar in SVRs and non-SVRs. The maximum PEG-IFN effectiveness during the first PEG-IFN dose and the HCV-infected cell loss rate (δ), were significantly higher in SVRs compared to non-SVRs (median 95% vs. 86% [p = 0.013], 0.27 vs. 0.11 day-1 [p = 0.006], respectively). Patients infected with HCV genotype 1 had a significantly lower average first-week PEG-IFN effectiveness (median 70% vs. 88% [p = 0.043]), however, 4- to 12-week PEG-IFN effectiveness was not significantly different compared to those with genotype 3 (p = 0.114). Genotype 1 had a significantly lower δ compared to genotype 3 (median 0.14 vs. 0.23 day-1 [p = 0.021]). The PEG-IFN concentration that decreased HCV production by 50% (EC50) was lower in genotype 3 compared to genotype 1 (median 1.3 vs. 3.4 [p = 0.034]). Conclusions: Both the HCV-infected cell loss rate (δ) and the maximum effectiveness of the first dose of PEG-IFN-α-2a characterised HIV co-infected patients and were highly predictive of SVR. Further studies are needed to validate these viral kinetic parameters as early on-treatment prognosticators of response in patients with HCV and HIV.

Nonresponder patients with hepatitis C virus genotype 2/3 infection: A question of low systemic interferon concentrations? (Article)

2010-02-15T00:00:00Z

Twelve of 303 per-protocol patients were nonresponders in a 12-week versus 24-week treatment study of hepatitis C virus (HCV) genotype 2/3 infection. The nonresponders had significantly lower interferon concentrations, as well as significantly greater mean age, body mass index, and viral load. Suboptimal drug concentrations may thus contribute to lack of response to therapy in patients with infection due to HCV genotype 2/3.

Exacerbated innate host response to SARS-CoV in aged non-human primates (Article)

2010-02-01T00:00:00Z

The emergence of viral respiratory pathogens with pandemic potential, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and influenza A H5N1, urges the need for deciphering their pathogenesis to develop new intervention strategies. SARS-CoV infection causes acute lung injury (ALI) that may develop into life-threatening acute respiratory distress syndrome (ARDS) with advanced age correlating positively with adverse disease outcome. The molecular pathways, however, that cause virus-induced ALI/ARDS in aged individuals are ill-defined. Here, we show that SARS-CoVinfected aged macaques develop more severe pathology than young adult animals, even though viral replication levels are similar. Comprehensive genomic analyses indicate that aged macaques have a stronger host response to virus infection than young adult macaques, with an increase in differential expression of genes associated with inflammation, with NF-κB as central player, whereas expression of type I interferon (IFN)-β is reduced. Therapeutic treatment of SARS-CoV-infected aged macaques with type I IFN reduces pathology and diminishes pro-inflammatory gene expression, including interleukin-8 (IL-8) levels, without affecting virus replication in the lungs. Thus, ALI in SARS-CoV-infected aged macaques developed as a result of an exacerbated innate host response. The anti-inflammatory action of type I IFN reveals a potential intervention strategy for virus-induced ALI.

Therapeutic response to peg-IFN-alpha-2b and ribavirin in HIV/HCV co-infected African-American and Caucasian patients as a function of HCV viral kinetics and interferon pharmacodynamics (Article)

2009-11-01T00:00:00Z

METHOD:: In this study we sought to characterize the relationship between several pharmacokinetic and pharmacodynamic parameters and virologic responses among HIV/hepatitis C virus genotype-1 co-infected patients receiving pegylated interferon-alpha-2b (peg-IFN2b) and ribavirin. We also tried to establish the underlying mechanisms that lead to poor sustained virologic responder rates observed with African-Americans against Caucasians and compared their results with those observed in a cohort of hepatitis C virus mono-infected patients. RESULTS:: Among our studied population, a viral decline of more than 1.0 log at day 3 combined with viral load of less than 5.0 log IU/ml at day 28 predicted sustained virologic responders with negative predictive value 100% and positive predictive value 100%. African-Americans had significantly (P < 0.01) slower hepatitis C virus viral kinetics as compared to Caucasians. However, peg-IFN2b concentrations and pharmacokinetic parameters, peg-IFN2bmax and peg-IFN2b half-life, were similar in both groups and did not predict sustained virologic responders. Nevertheless, the pharmacodynamic parameter EC50, estimated from nonlinear fitting of the viral kinetics together with peg-IFN2b concentration data, showed that HIV/ hepatitis C virus co-infected African-Americans have lower sensitivity to interferon-alpha thus giving rise to slower viral decline. The combined pharmacokinetic/pharmacodynamic parameter IFNmax/EC90 was an excellent predictor of sustained virologic responders, thus showing the importance of maintaining peg-IFN2b levels above EC90 to achieve successful treatment. CONCLUSION:: Further studies are needed to evaluate whether these pharmacodynamic predictions are a result of differential host response to peg-IFN2b or other viral factors conferring relative resistance to peg-IFN2b.

The application of genomics to emerging zoonotic viral diseases (Article)

2009-10-01T00:00:00Z

Interspecies transmission of pathogens may result in the emergence of new infectious diseases in humans as well as in domestic and wild animals. Genomics tools such as high-throughput sequencing, mRNA expression profiling, and microarray-based analysis of single nucleotide polymorphisms are providing unprecedented ways to analyze the diversity of the genomes of emerging pathogens as well as the molecular basis of the host response to them. By comparing and contrasting the outcomes of an emerging infection with those of closely related pathogens in different but related host species, we can further delineate the various host pathways determining the outcome of zoonotic transmission and adaptation to the newly invaded species. The ultimate challenge is to link pathogen and host genomics data with biological outcomes of zoonotic transmission and to translate the integrated data into novel intervention strategies that eventually will allow the effective control of newly emerging infectious diseases.

Early upregulation of acute respiratory distress syndrome-associated cytokines promotes lethal disease in an aged-mouse model of severe acute respiratory syndrome coronavirus infection (Article)

2009-07-01T00:00:00Z

Several respiratory viruses, including influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV), produce more severe disease in the elderly, yet the molecular mechanisms governing age-related susceptibility remain poorly studied. Advanced age was significantly associated with increased SARS-related deaths, primarily due to the onset of early- and late-stage acute respiratory distress syndrome (ARDS) and pulmonary fibrosis. Infection of aged, but not young, mice with recombinant viruses bearing spike glycoproteins derived from early human or palm civet isolates resulted in death accompanied by pathological changes associated with ARDS. In aged mice, a greater number of differentially expressed genes were observed than in young mice, whose responses were significantly delayed. Differences between lethal and nonlethal virus phenotypes in aged mice could be attributed to differences in host response kinetics rather than virus kinetics. SARS-CoV infection induced a range of interferon, cytokine, and pulmonary wound-healing genes, as well as several genes associated with the onset of ARDS. Mice that died also showed unique transcriptional profiles of immune response, apoptosis, cell cycle control, and stress. Cytokines associated with ARDS were signifi-cantly upregulated in animals experiencing lung pathology and lethal disease, while the same animals experienced downregulation of the ACE2 receptor. These data suggest that the magnitude and kinetics of a disproportionately strong host innate immune response contributed to severe respiratory stress and lethality. Although the molecular mechanisms governing ARDS pathophysiology remain unknown in aged animals, these studies reveal a strategy for dissecting the genetic pathways by which SARS-CoV infection induces changes in the host response, leading to death. Copyright

Virogenomics: the virus-host interaction revisited (Article)

2008-10-01T00:00:00Z

Genomics tools allow us to assess gene expression 'genome wide' providing an unprecedented view on the host-side of the virus-host interaction. The success of the application of these tools crucially depends on our ability to reduce the total information load while increasing the information density of the data collected. In addition to the advanced data analysis algorithms, gene annotation-pathway databases, and theoretical models, specifically designed sets of complementary experiments are crucial in translating the collected genomics data into palatable knowledge. A better understanding of the molecular basis of virus-host interactions will support the rational design of improved and novel intervention strategies for viral infections.

DC-SIGN enhances infection of cells with glycosylated West Nile virus in vitro and virus replication in human dendritic cells induces production of IFN-α and TNF-α (Article)

2008-07-01T00:00:00Z

The recent introduction of West Nile virus (WNV) into the Western hemisphere resulted in significant human outbreaks causing disease of variable severity. Previous studies classified WNV into two major lineages (L1 and L2) that differ in their virulence. Since most L1 strains are glycosylated, we investigated the role of dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN) in infection efficiency of glycosylated WNV strains. We showed that glycosylated strains, in contrast to non-glycosylated strains, infected DC-SIGN expressing cells more efficiently than DC-SIGN negative cells. Furthermore, WNV can productively infect cultured human dendritic cells (DCs) and infection of dendritic cells with the glycosylated WNV-NY99 L1 strain induced production of significantly more TNF-α and IFN-α in cultured DC, than infection with the non-glycosylated B956 L2 strain. Together, these results indicate that DC-SIGN enhances infection of cells by WNV glycosylated strains, which may at least in part explain the higher pathogenicity of glycosylated L1 strains versus most non-glycosylated L2 strains.

Pathology of experimental SARS coronavirus infection in cats and ferrets (Article)

2008-07-01T00:00:00Z

The pathology of severe acute respiratory syndrome-coronavirus (SARS-CoV) infection in cats and ferrets is poorly described, and the distribution of angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV, in the respiratory tracts of these species is unknown. We observed SARS-CoV antigen expression and lesions in the respiratory tracts of 4 cats and 4 ferrets at 4 days postinoculation and ACE2 expression in the respiratory tracts of 3 cats and 3 ferrets without infection. All infected cats and ferrets had diffuse alveolar damage associated with SARS-CoV antigen expression. A novel SARS-CoV- associated lesion was tracheo-bronchoadenitis in cats. SARS-CoV antigen expression occurred mainly in type I and II pneumocytes and serous cells of tracheo-bronchial submucosal glands of cats and in type II pneumocytes of ferrets. ACE2 expression occurred mainly in type I and II pneumocytes, tracheo-bronchial goblet cells, serous epithelial cells of tracheo-bronchial submucosal glands in cats, and type II pneumocytes and serous epithelial cells of tracheo-bronchial submucosal glands in ferrets. In conclusion, the pathology of SARS-CoV infection in cats and ferrets resembles that in humans except that syncytia and hyaline membranes were not observed. The identification of tracheo-bronchoadenitis in cats has potential implications for SARS pathogenesis and SARS-CoV excretion. Finally, these results show the importance of ACE2 expression for SARS-CoV infection in vivo: whereas ACE2 expression in type I and II pneumocytes in cats corresponded to SARS-CoV antigen expression in both cell types, expression of both ACE2 and SARS-CoV antigen in ferrets was limited mainly to type II pneumocytes.

ALT and viral load decline during PEG-IFN alpha-2b treatment for HBeAg-positive chronic hepatitis B (Article)

2008-06-01T00:00:00Z

Background: Alanine aminotransferase (ALT) is one of the main indicators for inflammatory activity in chronic hepatitis B. During interferon-based therapy, approximately 25%-40% of patients exhibit an ALT flare. Objectives and study design: To analyze the relation between ALT and HBV-DNA during pegylated interferon alpha-2b (PEG-IFN) treatment and compare different patterns of on-treatment viral load decline with the occurrence of ALT flares. Results: Of the 123 patients included in this study 31 (25%) exhibited an ALT flare during treatment or follow-up. Six out of 8 (75%) host-induced flares, i.e. ALT flares which were followed by a HBV-DNA decrease associated with a favorable treatment outcome, occurred in patients with a delayed HBV-DNA decline pattern (delayed vs. non-delayed decline, p = .022); 5 of these 8 patients exhibited HBeAg loss and 4 even HBsAg loss at the end of follow-up. The prediction of ALT normalization was possible using on-treatment viral load. Based on the difference from baseline, the evolution of viral load and ALT level were strongly interrelated during treatment and follow-up. With a joint model we estimated a correlation coefficient of 0.38 (p < 0.001) during the first 4 weeks of the treatment and of 0.72 (p < 0.0001) thereafter. Conclusion: There was a strong relation between ALT and viral load in HBeAg-positive chronic hepatitis B patients treated with PEG-IFN alpha-2b, especially after 4 weeks of treatment. Patients with a delayed decline in viral load often exhibited a host-induced flare associated with a favorable outcome.

Complete genome analysis of hepatitis C virus subtypes 6t and 6u (Article)

2008-05-01T00:00:00Z

Hepatitis C virus (HCV) genomes exhibit high nucleotide sequence diversity. In this study, we performed complete genome sequence analysis of 11 HCV genotype 6 samples from Vietnam and Thailand. We identified nine HCV complete genomes belonging to subtypes 6a (D9), 6e (D42 and D88), 6f (TH52), 6i (TH24), 6l (D33), 6n (TH22 and TH31) and 6o (D85). Phylogenetic analysis of the core/E1 and NS5B regions from unclassified genotype 6 isolates from Asian immigrants in Canada revealed that two other viruses (D49 and D83) could be classified as novel candidates of HCV subtypes 6t and 6u.

Characterization of hepatitis C virus deletion mutants circulating in chronically infected patients (Article)

2007-11-01T00:00:00Z

Hepatitis C virus (HCV) has a linear positive-stranded RNA genome of ∼9,600 nucleotides in length and displays a high level of sequence diversity caused by high mutation rates and recombination. However, when we performed long distance reverse transcription-PCRs on HCV RNA isolated from serum of chronic HCV patients, not only full-length HCV genomes but also HCV RNAs which varied in size from 7,600 to 8,346 nucleotides and contained large in-frame deletions between El and NS2 were amplified. Carefully designed control experiments indicated that these deletion mutants are a bona fide natural RNA species, most likely packaged in virions. Moreover, deletion mutants were detected in sera of patients infected with different HCV genotypes. We observed that 7/37 (18.9%) of genotype 1, 5/43 (11.6%) of genotype 3, and 4/13 (30.7%) of genotype 6 samples contained HCV deletion mutant genomes. These observations further exemplify HCVs huge genetic diversity and warrant studies to explore their biological relevance. Copyright

HCV-Specific T-Cell Response in Relation to Viral Kinetics and Treatment Outcome (DITTO-HCV Project) (Article)

2007-10-01T00:00:00Z

Background & Aims: The second slope of viral decline induced by interferon treatment has been suggested to be influenced mainly by the hepatitis C virus (HCV)-specific T-cell response; however, this hypothesis needs to be validated by results derived from experimental studies. Methods: To address this issue, the HCV-specific T-cell response of 32 genotype-1-infected patients of the 270 patients enrolled in the dynamically individualized treatment of hepatitis C infection and correlates of viral/host dynamics phase III, open-label, randomized, multicenter trial was studied in relation to viral kinetics and treatment outcome. Results: Greater proliferative responses by HCV-specific CD8 cells were found before treatment in patients with a fast viral decline and with a sustained viral response. However, no significant improvement of HCV-specific CD8 responses was observed in the first weeks of therapy in both rapid viral responder and non-rapid viral responder patients. A mild enhancement of proliferative T-cell responses and a partial restoration of the cytotoxic T-cell potential was expressed only late during treatment, likely favored by HCV clearance. Conclusions: Early restoration of an efficient T-cell response does not seem to be an essential requirement for a rapid viral decline in the first weeks of treatment. However, patients presenting a better HCV-specific CD8 cell proliferative potential at baseline are more likely to present a rapid and sustained viral response. Therefore, future treatment protocols should consider the development of strategies aimed at improving HCV-specific T-cell responses.

Differential antiviral effect of PEG-interferon-α-2b on HIV and HCV in the treatment of HIV/HCV co-infected patients (Article)

2007-09-01T00:00:00Z

OBJECTIVE: The major antiviral effect of interferon (IFN)-α on hepatitis C virus (HCV) is blocking of virion production from infected cells. We now investigate the previously unknown mechanism of action of IFN-α against HIV. METHODS: HIV kinetics in parallel to HCV kinetics and IFN pharmacokinetics during pegylated-IFN-α-2b (1.5 μg/Kg q.w., PEG-IFN) and ribavirin (1-1.2 g daily) treatment in nine HIV patients co-infected with HCV genotype 1 were analyzed. In vivo modeling predictions of suppression of HIV replication by PEG-IFN in CD8-depleted peripheral blood mononuclear cells were verified by in vitro experiments. RESULTS: HCV and HIV show different viral decline patterns after administration of PEG-IFN. Unlike the bi-phasic decline shown by HCV, HIV shows a slow continuous decline during the first week, with no rebound when PEG-IFN levels decline. Fitting of HIV kinetics with known half-lives of free virus and infected cells indicates that the major effect of IFN on HIV is to block de novo infection rather than to block virion production. The magnitude of the antiviral effect is similar (mean 1.1 log10 decline at 7 days) to those of direct anti-HIV drugs, but shows an inverse correlation with baseline viremia. In vitro studies show that preincubation with IFN renders a suppression of HIV replication superior to that of treatment postinfection, thus corroborating the mathematical analysis in vivo. CONCLUSION: The complimentary antiviral properties of IFN-α and antiretroviral therapy suggest a role for pharmacokinetically improved formulations of IFN as part of salvage therapy for HIV-infected individuals.

Functional genomics highlights differential induction of antiviral pathways in the lungs of SARS-CoV-infected macaques. (Article)

2007-08-10T00:00:00Z

The pathogenesis of severe acute respiratory syndrome coronavirus (SARS-CoV) is likely mediated by disproportional immune responses and the ability of the virus to circumvent innate immunity. Using functional genomics, we analyzed early host responses to SARS-CoV infection in the lungs of adolescent cynomolgus macaques (Macaca fascicularis) that show lung pathology similar to that observed in human adults with SARS. Analysis of gene signatures revealed induction of a strong innate immune response characterized by the stimulation of various cytokine and chemokine genes, including interleukin (IL)-6, IL-8, and IP-10, which corresponds to the host response seen in acute respiratory distress syndrome. As opposed to many in vitro experiments, SARS-CoV induced a wide range of type I interferons (IFNs) and nuclear translocation of phosphorylated signal transducer and activator of transcription 1 in the lungs of macaques. Using immunohistochemistry, we revealed that these antiviral signaling pathways were differentially regulated in distinctive subsets of cells. Our studies emphasize that the induction of early IFN signaling may be critical to confer protection against SARS-CoV infection and highlight the strength of combining functional genomics with immunohistochemistry to further unravel the pathogenesis of SARS.

The emerging role of ACE2 in physiology and disease (Article)

2007-05-01T00:00:00Z

The renin-angiotensin-aldosterone system (RAAS) is a key regulator of systemic blood pressure and renal function and a key player in renal and cardiovascular disease. However, its (patho)physiological roles and its architecture are more complex than initially anticipated. Novel RAAS components that may add to our understanding have been discovered in recent years. In particular, the human homologue of ACE (ACE2) has added a higher level of complexity to the RAAS. In a short period of time, ACE2 has been cloned, purified, knocked-out, knocked-in; inhibitors have been developed; its 3D structure determined; and new functions have been identified. ACE2 is now implicated in cardiovascular and renal (patho)physiology, diabetes, pregnancy, lung disease and, remarkably, ACE2 serves as a receptor for SARS and NL63 coronaviruses. This review covers available information on the genetic, structural and functional properties of ACE2. Its role in a variety of (patho)physiological conditions and therapeutic options of modulation are discussed. Copyright

Nonhuman primate models for SARS. (Article)

2006-05-01T00:00:00Z

Human monoclonal antibody as prophylaxis for SARS coronavirus infection in ferrets (Article)

2004-06-26T00:00:00Z

SARS coronavirus continues to cause sporadic cases of severe acute respiratory syndrome (SARS) in China. No active or passive immunoprophylaxis for disease induced by SARS coronavirus is available. We investigated prophylaxis of SARS coronavirus infection with a neutralising human monoclonal antibody in ferrets, which can be readily infected with the virus. Prophylactic administration of the monoclonal antibody at 10 mg/kg reduced replication of SARS coronavirus in the lungs of infected ferrets by 3·3 logs (95% Cl 2·6–4·0 logs; p<0·001), completely prevented the development of SARS coronavirus-induced macroscopic lung pathology (p=0·013), and abolished shedding of virus in pharyngeal secretions. The data generated in this animal model show that administration of a human monoclonal antibody might offer a feasible and effective prophylaxis for the control of human SARS coronavirus infection.

Pegylated interferon-alpha protects type 1 pneumocytes against SARS coronavirus infection in macaques (Letter To Editor)

2004-03-01T00:00:00Z

The primary cause of severe acute respiratory syndrome (SARS) is a newly discovered coronavirus. Replication of this SARS coronavirus (SCV) occurs mainly in the lower respiratory tract, and causes diffuse alveolar damage2, 7, 8. Lack of understanding of the pathogenesis of SARS has prevented the rational development of a therapy against this disease. Here we show extensive SCV antigen expression in type 1 pneumocytes of experimentally infected cynomolgus macaques (Macaca fascicularis) at 4 d postinfection (d.p.i.), indicating that this cell type is the primary target for SCV infection early in the disease, and explaining the subsequent pulmonary damage. We also show that prophylactic treatment of SCV-infected macaques with the antiviral agent pegylated interferon-alpha (IFN-alpha) significantly reduces viral replication and excretion, viral antigen expression by type 1 pneumocytes and pulmonary damage, compared with untreated macaques. Postexposure treatment with pegylated IFN-alpha yielded intermediate results. We therefore suggest that pegylated IFN-alpha protects type 1 pneumocytes from SCV infection, and should be considered a candidate drug for SARS therapy

Virology: SARS virus infection of cats and ferrets (Article)

2003-10-23T00:00:00Z

There is now a choice of animal models for testing therapies against the human virus. Top of pageAbstractThe reservoir of the coronavirus isolated from patients with severe acute respiratory syndrome (SARS)1, 2 is still unknown, but is suspected to have been a wild animal species. Here we show that ferrets (Mustela furo) and domestic cats (Felis domesticus) are susceptible to infection by SARS coronavirus (SCV) and that they can efficiently transmit the virus to previously uninfected animals that are housed with them. The observation that these two distantly related carnivores can so easily be infected with the virus indicates that the reservoir for this pathogen may involve a range of animal species

Molecular epidemiology of gibbon hepatitis B virus transmission (Article)

2003-01-01T00:00:00Z

Although transmission of human hepatitis B virus (HBV) variants to nonhuman primates is well documented, it remains to be elucidated whether nonhuman primate HBV is transmissible to humans. The prevalence and transmission routes of gibbon HBV were analysed in 101 captive gibbons in Thailand. Approximately 40 % of these animals showed at least one marker of HBV infection; 19 animals were chronic HBV carriers, characterized by elevated levels of alanine amino transferase and the presence of HBV DNA. Some of the chronic animals were found to be anti-HBc (HBV core antigen) negative (4 of 19), while precore promoter point mutations (nt 1762 or 1764) were determined in four animals by RFLP analysis. Phylogenetic tree analysis of the complete surface gene sequences revealed that gibbon viruses clustered separately from hepadnaviruses of other hosts. Evidence for horizontal and vertical transmission in captive gibbons was obtained. HBV DNA was also detected in the saliva of HBV carrier gibbons. Although some of the animal caretakers at the Krabok Koo Wildlife Breeding Centre were found to be chronic HBV carriers, genotype and sequence analysis did not reveal any evidence for zoonotic disease transmission.