Comparison between recombinant virus assay and live virus assay on evaluating anti-HIV-1 drugs / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To compaire results of recombinant virus assay and live virus assay on evaluateing anti-HIV-1 drugs.</p><p><b>METHODS</b>The pseudoviruse was generated by cotransfection of the plasmid B01 containing gp160 genes and pSG3 delta env plasmid. After co-incubation of pseudovirus with serially diluted drug, the EC50 and ED50 were calculated according to RLU(relative light unit) for each drug. After co-incubation of live virus with serially diluted drug, the EC50 was calculated according to cytopathic effect.</p><p><b>RESULTS</b>EC50 of IDV measured by the recombinant virus assay and live virus assay was 88.9 nmol/L, 89.5 nmol/L, respectively, while EC50 of NVP measured by the recombinant virus assay and live virus assay was 0.36 micromol/L, 0.23 micromol/L, respectively. The recombinant virus assay showed good reproducibility with coefficient variation of 0, however coefficient variation of live virus assay reached to 60%. ED50 of IDV and NVP measured by the recombinant virus assay were 70.6 nmol/L and 0.62 micromol/L, respectively. Coefficient variations for IDV and NVP were 14.3% and 9.7%, respectively.</p><p><b>CONCLUSION</b>The pseudoviruses could be used in evaluating anti-HIV-1 drugs. The recombinant virus assay showed good reproducibility and could calculate not only the EC50 but also the ED50 of drugs.</p>

The impact of the HIV-1 envelope (Env) mutation on its assembly of functional pseudovirus / 病毒学报

To find out whether the mutations of HIV-1 Env have influence on the assembly of pseudovirus and their abilities to infect cells, site-directed mutation (A457D)was performed using cycling mutagenesis and selection of mutants with DpnI. Transformation and plasmid purification technologies were used to obtain mutated env clone. Then both the prototype and the mutant were co-transfected with pSG3(delta(env)) to 293FT cells, respectively. Single-cycle infection assay was employed to analyze the effect of the prototype and the mutant on the ability of functional pseudovirus assembly. The transient expression of both the prototype S12-42-1 and mutant S12-42M were confirmed by Western blot essay. The S/CO value was less than 1 for S12-42-1 and 6.65 for S12-42M, demonstrating the functional pseudovirus was generated only for S12-42M. So mutation on HIV-1 Env has influence on the assembly of pseudovirus and their abilities to infect cells.

Epidemiological survey on the infection of hepatitis E virus among pigs in Henan province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate hepatitis E virus (HEV) infection among pigs in Henan province.</p><p><b>METHODS</b>A total of 623 swine sera, collected from 5 districts, were divided into two groups, under 3-month of age and over 3-month of age. They were tested for HEV antigen and antibody by using ELISAs, respectively. The sera positive for HEV antigen were tested for HEV RNA with RT-PCR. The positive products of RT-PCR were cloned and sequenced.</p><p><b>RESULTS</b>The positive rates of anti-HEV antibody of the groups under 3-month and over 3-month of age were 90.27% and 92.55%, respectively, without statistical difference, while those of HEV antigen were 15.93% and 5.69%, respectively, with significant difference. The positive rates of anti-HEV antibody and HEV antigen were significantly different among different districts. HEV RNA was detectable in 5 of 47 HEV antigen positive samples. The sequence analysis showed that in 4 of 5 specimens the sequence belonged to genotype 4 while in the remaining one the sequence was genotype 1.</p><p><b>CONCLUSION</b>The prevalence rate of HEV infection in pigs was high in Henan province and the rate differed in different districts.</p>

The preliminary analysis on immunogenicity of DNA vaccines against human papillomavirus 58 / 病毒学报

In order to evaluate the immunogenicity of HPV 58 L1 DNA vaccines, five DNA vaccines had been constructed with pcDNA3.1 vector containing different L1 genes of HPV 58, which were designated as L1h, L1hDeltac, L1S, L1SM and L1wt. The protein expression of DNA vaccines in vitro was tested by Western blot. The ability of forming pseudovirus was evaluated by transfecting DNA vaccine together with pcDNA3.1-h58L2 and pcDNA3.1-GFP into 293FT cells. The neutralizing antibodies and cellular immune response produced in BALB/c mice immunized with the DNA vaccines were detected by using pseudovirus-based neutralization assay and ELISPOT respectively. The results showed that the five DNA vaccines had been successfully constructed; the level of protein expression of L1hDeltac was the highest and those for L1S and L1SM were of medium, while no expressed target protein of L1wt was detected. Only L1S could form the pseudovirus while the other four vaccines could not. L1S and L1h could induce neutralizing antibody. However, the average titer of neutralizing antibody for L1S (1:6,400) was much higher than that for L1h (1:48) and the other three vaccines could not induce neutralizing antibody. No cellular immune response for all five DNA vaccines was detectable by ELISPOT. The results indicated that DNA vaccine against HPV 58 can form pseudovirus in vitro, also can induce high level of neutralizing antibodies. This provides reference for screening HPV vaccine in future.

Comparison of the reliability of two ELISA kits for detecting IgM antibody against hepatitis E virus / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the reliability of two ELISA kits for detecting IgM antibody against hepatitis E virus (HEV).</p><p><b>METHODS</b>Serum samples from 92 healthy subjects, 71 cases suspected of hepatitis E, 55 patients with confirmed diagnosis of acute hepatitis E, 50 individuals with rheumatoid factor (RF) positive and 54 persons with anti-HAV IgM positive were detected with three hepatitis E diagnostic kits. MP-IgM (MP, Singapore), Wantai-IgM and anti-HEV IgG (Wantai, China). HEV RNA was analyzed with RT-PCR in 52 of 71 cases suspected of hepatitis E.</p><p><b>RESULTS</b>In healthy subjects,cases suspected of hepatitis E and confirmed acute hepatitis E, the concordance between the two anti-HEV IgM reagents was 73.39% (160/218) and the significant differences in the positive rates of two assays were not observed [46.79% (102/218) vs 44.04% (96/218), chi2 = 0.62, P > 0.05]. Of 71 patients suspected of hepatitis E, the sensitivity for diagnosing acute hepatitis E of Wantai-IgM and MP-IgM were 83.08% (54/65) and 78.46% (51/65) (chi2 = 0.16, P > 0.05), respectively. Among those suspected of hepatitis E with HEV RNA positive, the sensitivity of Wantai-IgM was obviously higher than that of MP-IgM [(97.14%, 34/35) vs (74.29%, 26/35), chi2 = 4.9, P < 0.05]. 48 of 55 patients (87.27%) with confirmed diagnosis of hepatitis E were Wantai-IgM positive while 37 (67.27%) was MP-IgM positive (chi2 = 4.0, P < 0.05). The specificity of Wantai-IgM was higher than MP-IgM [100.00% (202/202) vs 89. 11% (180/202), chi2 = 20.05, P < 0.005]. RF and anti-HAV IgM might cause MP-IgM false positive without interference on Wantai-IgM.</p><p><b>CONCLUSION</b>Wantai-IgM should be a good ELISA kit for the diagnosis of acute hepatitis E.</p>

Expression of ORF2 protein of HEV genotype IV in Hansenula polymorpha / 生物工程学报

Hepatitis E, an acute infectious disease transmitted via the fecal-oral route, is caused by hepatitis E virus. However, no effective treatment currently exists for hepatitis E, and the only epidemic control approach is vaccination. But so for there are no commercial vaccine for hepatitis E available in the world. To find a new expression system to develop recombinant hepatitis E vaccine, in this study the expression system of methylotrophic yeast Hansenula polymorpha was used to express the gene encoding amino acid 112 - 607 of the open reading frame 2 (ORF2) of hepatitis E virus (HEV) genotype IV. In order to achieve high expression level, the coding sequence was optimized according to codon usage bias of Hansenula polymorpha and synthesized through overlapping PCR. Subsequently the gene was subcloned into the multi-copy expression vectors of Hansenula polymorpha, which include pDGXHP1.0 (MOX promotor), pDGXHP2.0 (MOX promotor) and pDGXHP2.1 ( FMD promotor). The series of one-copy and multi-copy recombinant plasmids were transformed into ATCC26012(Ura3-) by electroporation. The transformants were cultured in selection media MDL and screened for the existence of foreign gene by PCR. Then the strains were induced in MM media and the expression products were detected by SDS-PAGE, ELISA and Western blot assays to select the high-level expression strains. The result of SDS-PAGE showed that the HEV ORF2 expression product was accumulated up to 12% of total cellular protein and its molecular weight is 56kD. The expression product showed high immunoreactivity detected by ELISA and the highest titer is 1:2048. The result of Western blot demonstrated that the expression product could be specifically recognized by the polyclonal antibody against HEV. The successful expression of HEV ORF2 protein in Hansenula polymorpha provides foundation for the further development of recombinant subunit vaccine against hepatitis E.

A study on the prevalence rates of human immunodeficiency virus, hepatitis B virus and hepatitis C virus infections in intravenous drug users / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study HIV, HBV and HCV infections in intravenous drug users.</p><p><b>METHODS</b>2025 blood samples from intravenous drug users were collected from Sichuan, Hunan, Guangxi and Xinjiang regions, and tested for anti-HIV, anti-HCV, HBsAg using enzyme-linked immuno-sobent assays (ELISAs).</p><p><b>RESULTS</b>The positive rates of anti-HIV,anti-HCV and HBsAg were14.7%-30.4%, 60.7%-85.5% and 6.6%-22.4% in the intravenous drug users, respectively. The co-infection rates of HIV/HBV, HIV/HCV, HCV/HBV and HIV/HCV/HBV were 0%-0.4%, 11.6%-27.2%, 2.3%-14.3% and 1.6%-4.8% respectively in this population.</p><p><b>CONCLUSION</b>The infection rates of HIV, HBV and HCV were higher in the intravenous drug users than that in general populations in the same regions, and HIV/HCV co-infection appeared most frequent in this population.</p>

Evaluation of procleix HIV/HCV RNA diagnostic assay / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To investigate the sensitivity and specificity of Procleix HIV/HCV RNA diagnostic assay.</p><p><b>METHODS</b>HIV antibody positive or suspected positive plasmas of blood donors were collected from different provinces and detected with HIV antibody ELISA and HCV antibody ELISA. Samples positive for HIV by ELISA were confirmed by using HIV Blot. All the plasma samples were detected with Procleix HIV/HCV assay, HIV-1 discriminatory assay and HCV discriminatory assay, respectively.</p><p><b>RESULTS</b>All 74 samples positive for both HIV and HCV antibody were positive and 5 samples negative for both HIV and HCV antibody were negative when detected using Procleix HIV/HCV assay; 82 of 84 supplemental HIV antibody positive samples and 6 of 12 supplemental indeterminate samples were positive for HIV RNA, and all 7 HIV antibody negative samples were negative for HIV RNA when detected by using Procleix HIV discriminatory assay. Seventy of 81 HCV antibody positive samples and 4 of 22 HCV antibody negative samples were positive for HCV RNA when detected by using Procleix HCV discriminatory assay.</p><p><b>CONCLUSION</b>This reagent is more sensitive and could be used in blood screening, thereby can reduce both HIV and HCV transmission of blood in window period of HIV and HCV infection.</p>

Expression of HBV S and preS1 fusion gene in Pichia pastoris expression system / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To clone and express the ss1 recombinant gene containing S gene and preS1 (10-50 AA) gene in P. pastoris expression system.</p><p><b>METHODS</b>The fusion gene ss1 containing the S (1-222 AA) gene and preS1 (10-50 AA) gene was constructed with PCR method. The fusion ss1 gene was cloned into the expression vector of pPIC3.5k. The linear vector DNA was transformed into the host cell of GS115 with electroporation method. After screening with G418, the product was induced to express with methanol and its antigenicity was analyzed.</p><p><b>RESULTS</b>The molecular weight of expressed ss1 protein was about 30,000 dalton. The product was reactive to anti-HBs and anti-preS1 mAb.</p><p><b>CONCLUSION</b>The fusion gene was efficiently expressed in P. pastoris expression system.The expressed products have the antigenicity of both S and preS1 protein.</p>

Study on the response of specific antibodies against SARS-CoV in patients infected with SARS / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the response of specific antibodies against severe acute respiratory syndrome (SARS)-CoV in patients infected with SARS.</p><p><b>METHODS</b>IgM-capture, indirect and antigen-sandwiched enzyme linked immunosorbent assay (ELISA) were used to detect the SARS-CoV specific IgM, IgG and total antibodies in sera of clinical SARS patients or non-SARS individuals.</p><p><b>RESULTS</b>The positive rates of IgM, IgG and total antibodies to SARS-CoV in 146 sera of SARS patients collected in different phases of the disease were 61.64%, 53.43% and 69.86%, respectively. The earliest detectable days after onset of the disease for IgM and IgG to SRAS-CoV were 7 and 12 days, respectively. The specific IgM disappeared as early as 42 days after the onset of SARS. Of 70 sera from hepatitis A patients, 2 showed false positive results, while 127 sera from other patients were all negative, detected by the 3 methods. Serum from one medical worker who had been close contact to SARS patients was positive for anti-SARS-CoV IgG and total antibodies. These 3 methods used for detection were all not influenced by rheumatoid factor (RF).</p><p><b>CONCLUSION</b>All of the three methods were specific and sensitive for the detection of specific antibodies to SARS-CoV, and useful for epidemiological research and clinical diagnosis, but not for early diagnosis of SARS.</p>

Comparison among four kits in detection of anti-SARS-CoV IgG in sera of SARS patients / 中华流行病学杂志

<p><b>OBJECTIVE</b>To compare the sensitivity and specificity of four kits for detection of anti-severe acute respiratory syndrome (SARS)-CoV IgG in sera of SARS patients.</p><p><b>METHODS</b>Anti-SARS-CoV IgG was detected in 99 serial sera from 18 SARS patients and in 123 negative reference sera, using two enzyme linked immunosorbent assays (EIA No. A and No. B) and two indirect immunofluorescence assays (Australian IFA and Euroimmun IFA).</p><p><b>RESULTS</b>Anti-SARS-CoV IgG was not detected in sera collected from SARS patients at the first week after onset by any of the four kits, however, it was detectable in sera obtained at the second week of illness by EIA No. B, and two IFA, but not by EIA No. A, with the positive rates of 57.1% (4/7), 57.1% (4/7) and 42.9% (3/7), respectively. The anti-SARS-CoV IgG was first determined in sera on the 9th day by Euroimmun IFA, 12th day by EIA No. B, 13th day by Australian IFA, and 16th day by EIA No. A. The positive rates of antibody on the 3rd week after onset were 84.2% (16/19), 94.7% (18/19), 78.9% (15/19) and 52.6% (10/19) respectively. They were identical since the 4th week after the disease onset. Through detection of 123 negative reference sera, the specificity of EIA No. A and two IFA was 100%, with exception of 94.9% for EIA No. B.</p><p><b>CONCLUSION</b>The sensitivity and specificity of the two IFAs were relatively higher than that of the two EIAs. The quality of the two homemade EIAs should be improved.</p>

Prevalence of anti-HEV among swine, sheep and chickens / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To investigate the prevalence of anti-HEV among swine, sheep and chickens.</p><p><b>METHODS</b>Totally 498 sera of swine, sheep and chickens collected from Xingjiang, Guangxi, Guangdong, Beijing and Hebei were detected for the anti-HEV by an enzyme linked immunoassay.</p><p><b>RESULTS</b>The anti-HEV positive rate of swine was 67.53%(104/154), in pigs between 4-5 months of age the rate was 100.00%(9/9) from Xingjiang. The rate in pigs under 3 months of age from Guangxi was 36.00%(9/25) and in pigs older than six months of age was 71.67% (86/120), respectively. The 108 sera of sheep collected from Xingjiang were all negative. The positive rate of chickens was only 1.27% (3/236). The anti-HEV prevalence rates of chickens from Luoding, Shenzhen, Liuzhou, Beijing and Hebei were 4.00%, 1.49%, 1.49%, 0, 0 respectively.</p><p><b>CONCLUSION</b>HEV infection does exist among swine and chickens. The anti-HEV prevalence of swine was the highest among domestic animals. The role of swine and chickens in transmission of HEV needs to be further studied.</p>

Establishment of the reference panel for HIV RNA / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To establish a national reference panel for HIV RNA diagnostic reagents.</p><p><b>METHODS</b>Sera from patients with HIV infection and healthy blood donors were collected and tested for HIV and HCV antibodies and HBsAg by using ELISA. The HIV antibody positive samples with ELISA were confirmed with HIV Blot 2.2 (Genelabs). The quantitative samples for HIV RNA were calibrated with the WHO HIV RNA standard. The stability of the panel was evaluated with acceleration method.</p><p><b>RESULTS</b>After screening and calibration, 8 negative samples, 8 positive samples, 3 quantitative samples, 6 sensitivity samples and 5 samples for linear analysis were composed of the national reference panel for HIV RNA. The convinced international units (IU) for the quantitative samples were obtained by seven independent calibration and the logarithm of international units for the quantitative samples (b1-b3) were less than x +/- s. The results showed that this panel may stabilize for 4 days at 4 degrees C.</p><p><b>CONCLUSION</b>A national reference panel for HIV RNA reagents has been established. It may provide the basis for evaluating HIV RNA diagnostic reagents.</p>

Clinical significance of detecting RNA and anti HEV antibody in convalesent sera in patients with acute HEV hepatitis / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the anti hepatitis E virus (HEV) and HEV RNA in acute and convalescent sera of patients with NonA-E acute hepatitis.</p><p><b>METHODS</b>The serum samples were taken from 95 patients who were diagnosed as acute NonA-E hepatitis. Enzyme immunoassay (EIA) was used for detecting anti-HEV Immunoglobulin G (IgG, Genolable and Wantai EIA anti-HEV kits). RT-PCR amplification of HEV RNA was based on the open reading frame 2 region of HEV and the PCR products were sequenced.</p><p><b>RESULTS</b>Sera from 95 patients who were negative for anti-HEV in acute phase were followed up for 11-35 days to detect the anti-HEV antibody in recovery phase, 16/95 (16.84%) were positive for anti-HEV (wantai EIA anti-HEV kits). Ten (62.50%) were positive for HEV RNA in acute phase. Sequence analysis showed that 4 were HEV genotype. 6 were HEV genotype; 12/95 (12.50%) were positive for anti-HEV (Genolable EIA anti-HEV kits). Seven were positive for HEV RNA; 4 belonged to HEV genotype, 3 were HEV genotype.</p><p><b>CONCLUSION</b>It is significant and necessary to detect anti HEV antibody and HEV RNA in patients with HEV infection during acute phase and convalesent phase.</p>

Development and preliminary application of monoclonal antibodies against N protein of SARS virus / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To develop the monoclonal antibody against N protein of SARS virus and study its applicability.</p><p><b>METHODS</b>BALB/c mice were immunized with recombinant N protein. Spleen cells were collected and infused with SP2/0 cell. The infused cells were screened for anti-N protein antibody with ELISA. The positive cells were cloned and injected into abdominal cavity. The antibodies were purified from ascites. The affinities of those purified antibodies were analyzed with ELISA. The ELISA for detection of SARS virus antigen was developed by using antibody with the highest affinity. Its sensitivity and specificity were also evaluated primarily.</p><p><b>RESULTS</b>Eleven monoclonal cells secreting antibody have been developed. Three of the 11 purified monoclonal antibodies had very high affinity to N protein, while 4 purified McAbs showed very weak reaction to N protein, the affinities of remaining 4 McAbs were in between. The ELISA for detection of SARS virus antigen was developed with McAb 7. Its sensitivity was about 31 PFU/ml and had no cross reaction with other respiratory viruses.</p><p><b>CONCLUSION</b>The monoclonal antibody has good specificity and may be used to detect SARS virus antigen. However, its sensitivity is to be evaluated further with clinical samples from SARS patients, especially at acute phase.</p>

Prevalence of hepatitis B virus core promoter mutant isolated from asymptomatic carriers from areas with higher and lower incidence of hepatocellular carcinoma in Guangxi / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To understand the prevalence of HBV core promoter mutant (T1762 A1764 mutant) isolated from asymptomatic carriers from areas with higher and lower incidence of hepatocellular carcinoma (HCC) in Guangxi.</p><p><b>METHODS</b>A nested polymerase chain reaction (nPCR) was used for amplification of HBV DNA core promoter in sera, and then HBV DNA nPCR products were sequenced by direct sequencing.</p><p><b>RESULTS</b>The results show that 50.6% (39/77) of all HBV asymptomatic carriers were positive for HBV DNA HBV DNA positive rates of the samples from HCC higher incidence area, Longan County, and from lower incidence area, Guilin city were 55.6% (20/36) and 46.3% (19/41), respectively. HBV core promoter mutants could be seen in 35% in Longan positive samples and 47.4% in Guilin. The common mutations in both regions were all double mutations (nt 1,762 A-->T; nt 1,764 G-->A), accounting for 25% and 21%, respectively. The difference of the double mutant between Longan County and Guilin city was not significant (P>0.05).</p><p><b>CONCLUSIONS</b>These data implicated that the prevalence of HBV core promoter mutant isolated from asymptomatic carriers may not be correlated with the incidence of HCC in Guangxi.</p>

Preparation and application of the national reference panel for hepatitis B virus DNA / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To calibrate the national hepatitis B virus (HBV) DNA standard according to world health organization's standard material and prepare the national reference panel for HBV DNA reagents.</p><p><b>METHODS</b>Sera from blood donors and HBV patients were collected and detected by home-made HBV DNA PCR kits, HBsAg kits, and anti-HBc kits, and then confirmed by HBV DNA PCR kits produced by Roche in German, which was recognized by the world health organization. The stability of the panel was detected by acceleration method.</p><p><b>RESULTS</b>The convinced copies of the sensitivity samples were gotten by seven independent experiments, the coefficients of variation of logarithm of the copies of L0-L5 were all less than 15%. Regarding the national reference panel as the standard, the quality of most domestic HBV DNA PCR kits was improved, while part of the kits should be further qualified.</p><p><b>CONCLUSION</b>The national reference panel for HBV DNA reagents is developed. It contains eight negative, nine positive sera and seven samples for sensitivity test</p>

Capacity of HIV enzyme immunoassay diagnostic kits to detect antibodies against different genotypes of HIV / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the capacity of commercial HIV enzyme immunoassay (EIA) diagnostic kits to detect antibodies against different genotypes of HIV.</p><p><b>METHODS</b>HIV RNA was detected with RT-PCR from samples positive for HIV antibody. The purified PCR products were sequenced directly and the genotypes of HIV from samples were analyzed. The samples for each genotype of HIV were diluted and the diluted samples were detected with different HIV EIA diagnostic kits.</p><p><b>RESULTS</b>All 20 samples positive for HIV antibody were also positive for HIV RNA; 9 of 20 isolates were genotype B, 9 of them were genotype C or CRF BC, 2 of them were CRF AE. The sensitivity of different HIV EIA diagnostic kits to detect antibodies against different genotypes of HIV was not significantly different.</p><p><b>CONCLUSION</b>The capacity of commercial HIV diagnostic kits to detect antibodies against different HIV genotypes may not be significantly different.</p>

Human hepatitis B virus infection of tree shrews and Macaca assamensis in vivo / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To examine sensitivity of the tree shrews and Macaca assamensis to human hepatitis B virus (HHBV) by serologic methods.</p><p><b>METHODS</b>Totally 233 tree shrews and 28 Macaca assamensis were inoculated with human sera containing HBV. After inoculation, the sera were collected weekly from them and HBV markers were detected with HBV ditecting ELISA kits.</p><p><b>RESULTS</b>Ninety percent of the tree shrews developed acute infection, among them, 44.4 % persisted for over one year, 33.3% of them developed chronic infection persisted for 2 years and one month; the persistence of HBV in Macaca assamensis was much shorter.</p><p><b>CONCLUSION</b>These data clearly indicated that tree shrew may be used as an animal model for study of chronic HBV infection, whereas, Macaca assamensis, showed only a transient sensitivity to HHBV.</p>

Sequence Analysis of ORF3 and Partial ORF1 Region from Two Patients Infected with New Genotype of Hepatitis E Virus(HEV) / 中国病毒学

ORF3 and partial ORF1 regions were amplified with RT-PCR f rom two patients (T1 and T11)infected with new genotype of hepatitis E Virus. Th e PCR products were cloned and sequenced. The results showed that G-C rich regi on in ORF3 was deleted when amplified with normal PCR reaction. However, PCR rea ction containing G-C melt solution can overcome this problem. The sequence anal ysis showed that T1 and T11 belong to a new genotype of HEV which differs from g enotype I,II and III reported.T1 and T11 have 79%～82%, 80%～81% and 83%～85% id entical to genotype I,II and III respectively.