Effect of Viral Antigen Levels on the Serological Response and Efficiency of the Binary Ethylenimine-Inactivated Bluetongue Virus Serotype-16 Vaccine

Bluetongue (BT) is a serious hemorrhagic disease of ruminants caused by bluetongue virus (BTV). Inactive BTV vaccines have been successful in field trials in some areas, and inactivated vaccines are considered safer. However, information about the effect of the viral antigen level on the serological response and efficiency of the inactive BTV-16 vaccine is lacking. In the present study, the serological response and efficiency of the viral antigen concentration in the binary ethylenimine-inactivated Chinese BTV serotype-16 vaccine were investigated. The viral antigens in the viral suspension (VS) were quantified using a modified BTV AC-ELISA method. Four batches of vaccine containing 1, 5, 10, and 50 μg/ml of viral antigen were generated from the VS. Four groups of naive Chinese sheep were vaccinated with the different vaccine batches, and the serological response and vaccine efficiency were investigated before and after challenge infection. The vaccines containing 10 and 50 μg/ml of viral antigen induced significant ELISA and neutralizing antibody titers 14 days after vaccination, whereas the vaccines containing 1 and 5 μg/ml of viral antigen did not have these effects. A booster immunization at 21 days enhanced all groups’ antibody titers;however, the increased titer was related to the viral antigen level. In contrast to the serological response, the viral antigen level of the vaccines did not have a significant effect on the vaccine efficiency. With the exception of one sheep from the 5 μg/ml viral antigen group, all vaccinated sheep from the four antigen level groups showed strong resistance to infection based on their clinical symptoms, rectal temperatures and viremia. Collectively, these data suggested that viral antigen levels from 1 to 50 μg/ml had a significant effect on the serological response of the animals but a limited effect on the vaccine efficiency. The BTV-16 vaccine containing 1 μg/ml of viral antigen was sufficient to achieve high efficiency, but only the vaccines with more than 10 μg/ml of antigen induced a significant antibody response. To obtain a better serological response, we suggest the use of vaccines with more than 10 μg/ml of viral antigen. The findings in the study will be useful for BTV vaccine production.

Correlation between expression of HLA class Ⅱ antigen on hepatocyte membrane and viral replication in chronic hepatitis B virus carriers

In order to study the relationship between replicative status and human leucocyte antigens(HLA),HLA class Ⅱ antigen on hepatocyte membrane was analyzed in liver biopsies from 49 pa-tients with chronic hepatitis B virus infection.The results revealed that expression of HLA classⅡ antigen on hepatocyte membrane was observed in 57% (13/23) of hepatitis B e antigen (HBeAg)positive,only in 15% (4/26) of anti-HBe positive carriers.The display of HLA class Ⅱ antigen onhepatocyte membrane yeas found in 65% (11/17) hepatitis B core antigen (HBcAg) positive and in19% (6/32) HBcAg negative patients with chronic hepatitis B virus infection.There was nosignificant difference in the expression of HLA class Ⅱ antigen on hepatocyte membrane between mi-nor hepatic diseases and active liver diseases.These findings suggested that display of HLA classⅡ antigen on hepatocyte membrane might be associated with viral replication in the chronic hepati-tis B virus carriers.

Association of core promoter mutations of hepatitis B virus and viral load is different in HBeAg(+) and HBeAg(-) patients

AIM:To identify the prevalence of hepatitis B e antigen (HBeAg) and to assess the association of hepatitis B virus (HBV) core promoter mutations and viral load in Indonesian patients.METHODS:Sixty-four patients with chronic hepatitis,65 with liver cirrhosis and 50 with hepatocellular carcinoma were included in this study.HBeAg and hepatitis B e antibody (HBeAb) tests were performed using enzyme-linked immunosorbent assay and the mutations were analyzed by sequencing.Viral load was measured by real-time polymerase chain reaction.RESULTS:Of 179 patients,108 (60.3%) were HBeAg(-) and 86 (79.6%) of these HBeAg(-) patients had been seroconverted.The A1896 mutation was not found in HBeAg(+) patients,however,this mutation was detected in 70.7% of HBeAg(-) patients.This mutation was frequently found when HBeAg was not expressed (87.7%),compared to that found in HBeAg seroconverted patients (65.1%).The A1899 mutation was also more prevalent in HBeAg(-) than in HBeAg(+) patients (P=0.004).The T1762/A1764 mutation was frequently found in both HBeAg(+) and HBeAg(-) patients,however,the prevalence of this mutation did not significantly differ among the two groups (P=0.054).In HBeAg(+) patients,the T1762/A1764 mutation was correlated with lower HBV DNA (P < 0.001).The A1899 mutation did not correlate with HBV DNA (P=0.609).In HBeAg(-) patients,the T1762/A1764 mutation alone was not correlated with HBV DNA (P=0.095),however,the presence of either the T1762/A1764 or A1896 mutations was associated with increased HBV DNA (P < 0.001).CONCLUSION:The percentage of HBeAg(-) patients is high in Indonesia,and most of the HBeAg(-) patients had been seroconverted.The A1896 mutation was most likely the major cause of HBeAg loss.The T1762/A1764 mutation alone was associated with lower viral loads in HBeAg(+) patients,but not in HBeAg(-) patients.

Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV) infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified, including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host’s human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCV- specific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

Early hepatitis B viral DNA clearance predicts treatment response at week 96

AIM To investigate whether hepatitis viral DNA load at 24 wk of treatment predicts response at 96 wk in patients with chronic hepatitis B.METHODS A total of 172 hepatitis B envelope antigen(HBe Ag)-positive chronic hepatitis B patients who received initial treatment at 16 tertiary hospitals in Hunan Province, China were enrolled in this study. All patients received conventional doses of lamivudine and adefovir dipivoxil, telbivudine, entecavir dispersible tablets, or entecavir tablets for 96 wk. Patients who used other antiviral drugs or antitumor and immune regulation therapy were excluded. Patients were stratified into three groups according to their viral DNA load at 24 wk: < 10 IU/m L(group 1), 10-103 IU/m L(group 2), and > 103 IU/m L(group 3). Correlations of 24-wk DNA load with HBe Ag negative status and HBe Ag seroconversion at 96 wk were analyzed. Receiver operating characteristic curve analysis was used to test the predictive value of the HBV DNA load at 24 wk for long-term response.RESULTS The rates of conversion to HBe Ag negative status and HBe Ag seroconversion rates were 53.7% and 51.9%, respectively, in group 1; 35.21% and 32.39% in group 2; and 6.38% and 6.38% in group 3. The receiver operating characteristic curves for the three subgroups revealed that the lowest DNA load(< 10 IU/m L) was better correlated with response at 96 wk than a higher DNA load(10-103 IU/m L). Nested PCR was used for amplifying and sequencing viral DNA in patients with a viral DNA load > 200 IU/m L at 96 wk; resistance mutations involving different loci were present in 26 patients, and three of these patients had a viral DNA load 10-103 IU/m L at 96 wk. CONCLUSION Hepatitis B viral DNA load at 24 wk of antiviral treatment in patients with chronic hepatitis B is a predictor of the viral load and response rate at 96 wk.

An Indirect ELISA of Classical Swine Fever Virus Based on Quadruple Antigenic Epitope Peptide Expressed in E.coli

In this study,a synthesized quadruple antigenic epitope gene region of the classical swine fever virus (CSFV)E2 glycoprotein was expressed in E.coli to a obtain target protein.This target protein was used as a coating antigen to establish an indirect ELISA for specifically detecting anti-CSFV antibodies in serum samples from pigs.The P/N cut-off value of this assay was 1.92 by receiver operating characteristic curve(ROC)analysis based on 30 negative sera and 80 positive samples.The test gave 97.5%sensitivity and 96.7%specificity compared with the indirect hemagglutination(IHA)test.The inter-assay and intra-assay coefficients of variation (CVs)for 16 sera were both≤6.8%.No cross-reactivity between the coating antigen and anti-bovine viral diarrhoea virus(BVDV)antibodies was observed.

Establishment of transgenic mouse harboring hepatitis B virus (adr subtype) genomes

INTRODUCTIONHepatitis B virus (HBV) belongs to the group ofhepatovirus, a major pathogen of human acute andchronic hepatitis B[1 4], which has a very closeassociation with human hepatocellular carcinoma(HCC)[5-8], For example, a statistical data from ahospital in Shanghai showed that 80% of HCCpatients were positive for HBsAg ( personalcommunication).

Inhibition of hepatitis B virus by oxymatrine in vivo

AIM To investigate the anti-HBV effect ofoxymatrine (oxy) in vivo.METHODS HBV transgenic mice were producedby micro-injection of a 4.2kb fragmentcontaining the complete HBV genomes.Expression level of HBsAg and HBcAg in thetransgenic mice liver was determined byimmunohistochemical assay.RESULTS Four groups (6 mice in each group)were injected intraperitoneally with oxy at thedosage of 100,200, and 300 mg/kg or with salineonce a day for 30 days. Both HBsAg and HBcAgwere positive in livers of all the six mice in thecontrol group (injected with saline), and werepositive in livers of two mice in 100 mg/kg groupand 300mg/kg group. In 200mg/kg group,HBsAg and HBcAg were negative in livers of allthe six mice. Based on the results, 200 mg/kg isthe ideal dosage to explore the effect of oxy atdifferent time points. According to the oxytreatment time, mice were divided into fourgroups: 10 d, 20 d, 30 d and 60 d (4 mice in eachgroup). Each mouse underwent liver biopsy twoweeks before the treatment of oxy. Down-regulation of HBsAg and HBcAg appeared aftertreatment of oxymatrine for 10 d and 20 d, Dane-like particles disappeared after the treatment ofoxy for 20d under electron microscopy,however, the expression level of HBsAg andHBcAg returned to normal 60 d later after oxytreatment.CONCLUSION oxymatrine can reduce thecontents of HBsAg and HBcAg in transgenic miceliver, longer treatment time and larger dosagedo not yield better effects.

Hepatitis C virus infection of human hepatoma cell line 7721 in vitro

AIM: To establish a cell culture system with long-term replication of hepatitis C virus in vitro. METHODS: Human hepatoma cell line 7721 was tested for its susceptibility to HCV by incubating with a serum from a patient with chronic hepatitis C. Cells and supernatant were harvested at various phases during the culturing periods. The presence of HCV RNA, the expression of HCV antigens in cells and/or supernatant were examined by RTPCR, in situ hybridization and immunohistochemistry respectively. RESULTS: The intracellular HCV RNA was first detected on d2 after infection and then could be intermittently detected in both cells and supernatant over a period of at least three months. The expression of HCV NS3,CP10 antigens could be observed in cells. The fresh cells could be infected by supernatant from cultured infected cells and the transmission of viral genome from HCV-infected 7721 cells to PBMCs was also observed. CONCLUSION: The hepatoma line 7721 is not only susceptible to HCV but also supports its long-term replication in vitro.

TT virus and hepatitis G virus infections in Korean blood donors and patients with chronic liver disease

AIM:To determine the prevalences of TTV and HGV infections among blood donors and patients with chronic liver disease in Korea,to investigate the association of TTV and HGV infections with blood transfusion,and to assess the correlation between TTV and HGV viremia and hepatic damage. METHODS:A total of 391 serum samples were examined in this study.Samples were obtained from healthy blood donors(n=110),hepatitis B surface antigen(HBsAg)-positive donors(n=112),anti-hepatitis C virus(anti-HCV)-positive donors(n=69),patients with type B chronic liver disease (n=81),and patients with type C chronic liver disease(n=19). Trv DNA was detected using the hemi-nested PCR.HGV RNA was tested using RT-PCR.A history of blood transfusion and serum levels of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)were also determined. RESULTS:TTV DNA was detected in 8.2%of healthy blood donors,16.1%of HBsAg-positive donors,20.3%of anti- HCV-positive donors,21.0%of patients with type B chronic liver disease,and 21.1%of patients with type C chronic liver disease.HGV RNA was detected in 1.8%of healthy blood donors,1.8%of HBsAg-positive donors,17.4%of anti-HCV-positive donors,13.6%of patients with type B chronic liver disease,and 10.5%of patients with type C chronic liver disease.The prevalence of TTV and HGV infections in HBV- or HCV-positive donors and patients was significantly higher than in healthy blood donors(P<0.05), except for the detection rate of HGV in HBsAg-positive donors which was the same as for healthy donors.There was a history of transfusion in 66.7%of TTV DNA-positive patients and 76.9%of HGV RNA-positive patients(P<0.05).No significant increase in serum ALT and AST was detected in the TTV or HGV-positive donors and patients. CONCLUSION:TTV and HGV infections are more frequently found in donors and patients infected with HBV or HCV than in healthy blood donors.However,there is no significant association between TTV or HGV infections and liver injury.

A comparative study on serologic profiles of virus hepatitis B

INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarcinoma. China and Korea both belong to high-risk endemic regions of viral hepatitis[1]. TheHBsAg positive rates in China ranged from 6.9% -17.9% by age, race and test methods[2-5].

Expression and significance of HBV genes and their antigens in human primary intrahepatic cholangiocarcinoma

AIM To explore the etiology and pathogenesis of human primary intrahepatic cholangiocarcinoma, the expression of HBV genes and HBV-antigens was detected in the cancerous tissue and its surrounding hepatic tissues.METHODS HBV-antigens were detected by immunohistochemical technique and HBV genes were examined with in situ hybridization.RESULTS In 20 cases of cholangiocarcinoma, the positive detection rate of HBxAg, pre-S1, pre-S2, HBsAg and HBcAg was 75%, 40%, 40%, 10% and 0%, respectively, and in the surrounding hepatic tissues of 19 cases the positive rates were 84.2%, 47.9%, 47.9%, 31.6% and 31.6%. Among 40 cases of cholangiocarcinoma, the positive rate of HBV-DNA, x gene, pre-s gene, s gene and s gene fell on 77.5%, 70.0%, 47.5%, 40% and 42.5%, respectively, and of the surrounding hepatic tissues in 33 cases, 87.9%, 84.8%, 63.6%, 69.7% and 66.7%.CONCLUSION The development of human primary intrahepatic cholangiocarcinoma bears a close relationship with chronic persistent HBV infection. Particularly, the x gene of HBV and its protein (HBxAg) might play an important role in pathogenesis of hepatic carcinoma.A large number of studies indicate a close relationship between human primary hepatocellular carcinoma and hepatitis B virus (HBV) infection, which is considered generally as an important factor in the development of hepatic carcinoma[1,2]. In human primary hepatic carcinoma, hepatocellular carcinoma is more frequently encountered, while intrahepatic cholangiocarcinoma (ChC), including hepatocholangiocarcinoma (HChC), is relatively less, being 8%-10%[3]. For a long time, the etiology and pathogenesis of intrahepatic cholangiocarcinoma have been unclear. A few reports considered it to be related to infestation with clonorchiasis sinensis[4,5], but never involved with HBV infection. We used immunohistochemical technique and in situ hybridization methods to detect HBV genes and their -related antigens in the tissues of intrahepatic cholangiocarcinoma and its surrounding hepatic tissues for the purpose of exploring the etiology and pathogenesis of intrahepatic cholangiocarcinoma.

Preparation and application of monoclonal antibodies against hepatitis C virus nonstructural proteins

AIM To prepare hybridoma cell lines which secrete anti HCV recombinant NS3 and NS5 proteins′ monoclonal antibodies, and to evaluate their usage in the study of the distribution of HCV NS3 and NS5 antigen in liver tissues. METHODS The hybridoma cell lines were raised using the spleen cells of BALB/C mouse immunized with recombinant NS3 and NS5 proteins according to the conventional protocols. The antibody secreting cells were screened using solid phase ELISA and cloned by limited dilution method. In order to determine the specificity of these hybridoma cell lines, the culture supernatant of these cells was western blot assayed with expression and nonexpresion E. coli and ELISA with other antigens, including HCV core and NS3 and HBsAg. Immunohistochemistry of 51 cases paraffin embedded liver tissues was performed to determine the distribution of HCV NS5 antigen as well as NS3 antigen in liver tissues. RESULTS Eight hybridoma cell lines secreting monoclonal antibodies against HCV NS3 and NS5 proteins were raised. They are named 2B6, 2F3, 3D8, 3D9, 8B2, 6F11, 4C6 and 7D9. Among them only 2B6 against NS3 protein can react with the polypipetides of C7 that is another recombinant polypipetides of NS3 gene. Others have no reaction with HCV core and HBsAg of HBV, and there is no cross reaction between NS3Ag and anti NS5Ag McAb and between NS5Ag and anti NS3 McAb. The immunohistochemistry results indicate that no HCV antigen was detected in the specimens of HBV infection in 20 cases. In 31 HCV infected specimens the positive rate of NS3Ag and NS5Ag are 51 6% (16/31) and 54 9% (17/31), respectively. There were six pure HCV infected specimens in these 31 specimens and half of them were HCV NS3Ag and NS5Ag positive. In the co infection of HBV and HCV group the positive rate of NS3Ag and NS5Ag were 52% (13/25) and 56% (14/25), respectively, almost the same with that of pure HCV infected group. The positive rates of HCV antigens were 70 6% (12/17) and 76 5% (13/17) in CAC patients. CONCLUSION The monoclonal antibodies we prepared are specific to the recombinant HCV NS3 and NS5 proteins and can be used in the clinical immunohistochemistry diagnosis.

DNA-guided hepatitis B treatment,viral load is essential,but not sufficient

Hepatitis B virus （HBV） infection is a global public health problem that concerns 350 million people worldwide. Individuals with chronic hepatitis B （CriB） are at increased risk of developing liver cirrhosis, hepatic de-compensation and hepatocellular carcinoma. To maintain undetectable viral load reduces chronic infection complications. There is no treatment that eradicates HBV infection. Current drugs are expensive, are associated with adverse events, and are of limited efficacy. Current guidelines try to standardize the clinical practice. Nevertheless, controversy remains about management of asymptomatic patients with CriB who are hepatitis B e antigen （HBeAg）-positive with normal alanine aminotransferase, and what is the cut-off value of viral load to distinguish HBeAg- negative CriB patients and inactive carriers. We discuss in detail why DNA level alone is not sufficient to begin treatment of CriB.

High-throughput RNA interference screens integrative analysis: Towards a comprehensive understanding of the virus-host interplay

Viruses are extremely heterogeneous entities; the size and the nature of their genetic information, as well as the strategies employed to amplify and propagate their genomes, are highly variable. However, as obligatory intracellular parasites, replication of all viruses relies on the host cell. Having co-evolved with their host for several million years, viruses have developed very sophisticated strategies to hijack cellular factors that promote virus uptake, replication, and spread. Identification of host cell factors(HCFs) required for these processes is a major challenge for researchers, but it enables the identification of new, highly selective targets for anti viral therapeutics. To this end, the establishment of platforms enabling genome-wide high-throughput RNA interference(HT-RNAi) screens has led to the identification of several key factors involved in the viral lifecycle. A number of genome-wide HT-RNAi screens have been performed for major human pathogens. These studies enable first inter-viral comparisons related to HCF requirements. Although several cellular functions appear to be uniformly required for the life cycle of most viruses tested(such as the proteasome and the Golgi-mediated secretory pathways), some factors, like the lipid kinase Phosphatidylinositol 4-kinase Ⅲα in the case of hepatitis C virus, are selectively required for individual viruses. However, despite the amount of data available, we are still far away from a comprehensive understanding of the interplay between viruses and host factors. Major limitations towards this goal are the low sensitivity and specificity of such screens, resulting in limited overlap between different screens performed with the same virus. This review focuses on how statistical and bioinformatic analysis methods applied to HTRNAi screens can help overcoming these issues thus increasing the reliability and impact of such studies.

“Anti-HBc alone” in human immunodefi ciency virus-positive and immuno-suppressed lymphoma patients

Hepatitis B virus (HBV) infection is endemic in various parts of the world. A proportion of patients have resolved prior exposure to HBV, as evidenced by the clearance of circulating hepatitis B surface antigen and the appearance of antibody to hepatitis B core antigen (anti-HBc), which could produce protective antibody to hepatitis B surface antigen (anti-HBs). With time, anti-HBs in some patients may become negative. Such patients are described as having occult HBV infection or "anti-HBc alone". In the context of immunodef icient patients, such as HIV patients or lymphoma patients undergoing immunosuppressive immunotherapy, the lack of protective anti-HBs may increase the risk of hepatitis B reactivation. Serum HBV DNA testing may be necessary in "anti-HBc alone" patients, to detect patients at a high risk of developing HBV infection allowing appropriate prophylactic management.

Molecular interactions between hepatitis B virus and delta virus

As a deficient virus due to the lack of envelope proteins, hepatitis D virus(HDV) causes chronic or fulminant "delta hepatitis" only in people with simultaneous hepatitis B virus(HBV) infection. HBV encodes three types of surface proteins known as small(S), medium(M) and large(L) envelope proteins. All three types of HBV surface antigens(HBs Ags) are present on HDV virions. The envelopment process of HDV occurs through interactions between the HDV ribonucleoprotein(RNP) complex and HBV HBsA gs. While HBsA g is the only protein required by HDV, the exact interaction sites between the S protein and pre-mature HDV are not well defined yet. In fact, these sites are distributed along the S protein with some hot spots for the envelopment process. Moreover, in most clinically studied samples, HDV infection is associated with a dramatically reduced HBV viral load, temporarily or permanently, while HBsA g resources are available for HDV packaging. Thus, beyond interacting with HBV envelope proteins, controlling mechanisms exist by which HDV inhibits HBV-DNA replication while allowing a selective transcription of HBV proteins. Here we discuss the molecular interaction sites between HBs Ag and the HDV-RNP complex and address the proposed indirect mechanisms, which are employed by HBV and HDV to facilitate or inhibit each other's viral replication. Understanding molecular interactions between HBV and HDV may help to design novel therapeutic strategies for delta hepatitis.

Predictors of loss of hepatitis B surface antigen in HIV-infected patients

AIM:To study factors associated with loss of hepatitis B surface antigen (HBsAg) in patients co-infected with human immunodeficiency virus (HIV) and hepatitis B virus (HBV).METHODS:We retrospectively reviewed the medical records of 5681 patients followed up at two New York City HIV clinics from January 1999 to May 2007.Clinical and laboratory parameters including baseline and follow-up HIV viral loads,CD4 cell counts,alanine transaminase levels,demographics,presence of hepatitis C infection,and treatment with highly active antiretroviral therapy dually active against both HIV and HBV infection,were analyzed to determine factors associated with loss of HBsAg.RESULTS:Three hundred and fifty five patients (355/5681,6.84%) were co-infected with HIV and HBV and were evaluated.Of these,226 patients with more than 12 mo follow-up were included in further analysis to determine factors associated with loss of HBsAg in the long-term follow-up.In the univariate analysis,baseline CD4 cell count was associated with loss of HBsAg (P=0.052).Cox regression analysis revealed that loss of HBsAg was associated with baseline CD4 cell count > 500 cells/mm3 (P=0.016,odds ratio:76.174,95% confidence interval:2.233-2598.481).CONCLUSION:Our study showed an interesting association of loss of HBsAg in HIV-HBV co-infected patients with higher CD4 cell count,suggesting that T-cell cytolytic activity against HBV may still be effective in clearing HBV infection.

Dengue outbreak in Swat and Mansehra,Pakistan 2013;an epidemiological and diagnostic perspective

Objective:To High light some epidemiological,clinical and diagnostic features of dengue fever during an outbreak and the role of different diagnostic techniques to achieve the highest level of accuracy in results.Methods:Blood samples(n=323) were collected along with epidemiological and clinical data from suspected dengue patients who visited different hospitals in Swat and Mansehra district of Pakistan between May-November 2013 during a dengue outbreak.Samples were tested for the detection of viral nucleic acid by real-lime PCR.non structural protein-1(NS1antigen and IgM antibodies by ELISA.Results:Out of 323 cases with clinical dengue infection,304 were positive by one or more diagnostic parameter:201 samples were positive by real-time PCR,209 were positive by NS1 ELISA and 190 were positive by IgM antibodies.Sensitivities of real-time PCR and NS1 F.LISA were comparable for early diagnosis of dengue virus infection.IgM antibody detection assay was found useful for the diagnosis in the samples collected later than day 5 of onset.Conclusions:The use of real-lime PCR or detection of non stnictural protein NS 1 by ELISA followed by IgM antibodies detection can be recommended for early diagnosis of dengue virus infection with a high level of accuracy.

Research review Study and application of monoclonal antibodies against herpes simplex virus

The results of research work completed in recent years in the authors’ laboratory withmonoclonal antibodies (McAbs) against herpes simplex virus (HSV) are reported in this paper as fol-lows.(1) Eighteen hybridoma cell lines steadily producing McAbs against HSV were established byhybridoma technic.(2) The mechanisms of neutralization in vitro and animal protection in vivo medi-ated by different McAbs were investigated.(3) A method of detecting virus antigua was developedwith the McAbs.(4) Tne isolates of virus were typed and antigenically analysed by type-specificand type-common McAbs.(5) HSV antigen in clinical spectimens was detected and directly typed byan ELISA method coating with type-specific and type-common McAb.(6) The target antigens ofMcAbs were identified,purified,and their genes were localized.(7) Experimental rabbitHSV keratitis was treated with McAbs.