GENE ENGINEERING EB VIRUS MEMBRANE ANTIGEN IN DETECTION OF MA-IgA ANTIBODY(COMPARISON WITH VCA-IgA AND EA-IgA ANTIBODIES)

With gene engineering EB virus membrane antigen as the diagnostic antigen, indirect immunofluo-rescence (IF) assay was used to detect IgA antibody against EB virus membrane antigen (MA-IgA) in sera from 202 nasopharyngeal carcinoma (NPC) patients and 315 controls (normal and patients with other tumors). MA-IgA antibody was positive in 96.8% of the pretreatment NPC patients with a GMT of 1:36.3. MA-IgA detection by this method was more sensitive than EA-IgA detection by IE. In contrast, patients with tumors other than NPC were negative for MA-IgA antibody. 9.1% of VCA-IgA positive persons were MA-IgA positive with a GMT of less than 1:5. No MA-IgA positive was found in VCA-IgA negatives. The results indicated that this method was relatively specific. In the treatment group, the positive rate and GMT of MA-IgA antibody declined with increase in survival time and the decline was faster than VCA-IgA. When recurrence or distant metastasis developed, similar to VCA-IgA and EA-IgA antibodies, the positive rate and GMT of MA-IgA antibody increased to its pretreatment level. Therefore, MA-IgA detection might be valuable in the early diagnosis and monitor of NPC.

CLINICAL SIGNIFICANCE OF DETECTING SERUM ANTIBODIES TO NUCLEOPROTEIN AND GLYCOPROTEIN G_2 OF HANTAAN VIRUS IN PATIENTS WITH HEMORRHAGIC FEVER WITH RENAL SYNDROME

Antibody blocking enzyme linked immunosorbent assays, respectively detecting antibodies to Hantaan virus nucleoprotein (NPAb) and glycoprotein GZ (G,Ab), were developed using monoclonal antibody L133, L13r3, LV48A and LVZB28B NPAb and GZAb in 291 serum samples from 65 patientswith kemorrkagic fever with renal syudrome (HFRS) were detfrmlned by these methods. The positive rates or NPAb were 90N on day 2-3 and 100 % on day 8-9 arter onset of disease, respectively.NPAb titers Increased during fever period and reached Peak levels during kypotensive and oliguric periods of HFRS. It was suggested that NPAb might be an important component Involved in the immunopathogenlc lin'alrmeut of HFRS and the detection of NPAb might be useful for the early diagnosis or HFRS. The I,osltlve rates and titers of GZAh were very low during the rirst three periods,namely rever, hypoteuslve and ollgurlc periods, and reached high levels during the convalescent period. GRAb titers were negatively related to the I,rotelnurla levels during the course of HFRS. It wasIndicated that GZAb might be the main component or neutralizing autlhodles to Hantaan virus Infection and the efrlclent production or GZAb was a good marker ror predicting the recovery and betterprognosis of HFRS.

Hepatitis C virus micro-elimination:Where do we stand?

Hepatitis C virus (HCV) elimination by 2030, using direct-acting antiviraltreatments, has been promoted by the World Health Organization. Thisachievement is not attainable, however, particularly after the 2020 pandemic ofthe coronavirus disease 2019. Consequently, the more realistic objective ofeliminating HCV from population segments for which targeted strategies ofprevention and treatment are easily attained has been promoted in Europe, as avalid alternative. The underlying idea is that micro-elimination will ultimatelylead to macro-elimination. The micro-elimination strategy may target differentspecific populations and at-risk groups. Different settings, including prisons andhospitals, have also been identified as micro-elimination scenarios. In addition,dedicated micro-elimination strategies have been designed that are tailored at thegeographical level according to HCV epidemiology and individual country’sincome. The main elements of a valid and successful micro-elimination project arereliable epidemiological data and active involvement of all the stakeholders.Community involvement represents another essential component for a successfulprogram.

Comparison on Detection Results of PRV Wild Virus Antibody Provided by Different Institutions

The detection results from different institutions were performed at the first stage of PRV wild virus antibody supervision in swine breeding. The serum samples were collected from 71 individuals and each individual was sampled twice at one week interval. The results showed that the positive coincidences for gE antibody between two institutions were 35.71% and 45.45 % ：espectively, with the total detection coincidences of 87.32% and 91.55% correspondingly. The positive coincidences for gE antibody between the two detections of each institution were 40.00% and 75.00% respectively, with the total detection coincidences of 87.32% and 97.18% correspondingly. It indicates that it is very necessary to screen the detection institution at the first supervision stage of PRV wild vires for swine population.

Comparative Study on 4 EIA Kits for Screening Antibody to Hepatitis C Virus in Pooled Sera

Four enzyme immunoassay (EIA) test kits, 1 Canadian product and 3 Chinese products,were used in the comparative study. Each pool consisted of 5 sera, and the 5 single sera were tested as controls. The tests were carried out according to the instructions, keeping the same dilution of each serum in single and pool samples. It was found that with the Canadian kit,the positive and negative results of opled sera had no difference from that of the controls (P>0. 10). In the case of Chinese Yali and Kehua kits, the positive results of pooled sera showed no difference from the controls (P >0. 10), but the optical density (OD) of negative opls were increased (P < 0. 01 ), though quite distant from the cut-off values. In the case of Changzheng kit, the OD of opitive opls were significantly lower than those of the controls (P < 0. 05 ), and weak positive samples missed the detection. However this problem could be overcome by blocking the microwells beforehand. Our experiment demonstrate that not all EIA test kits are suitable for screening opls for antithey to hepatitis C virus, and that it is important to assess the sensitivity of the EIA kit to be used for this purpose.

Is there a need for universal double reflex testing of HBsAg-positive individuals for hepatitis D infection?

Hepatitis D virus(HDV)can infect HBsAg-positive individuals,causing rapid fibrosis progression,early decompensation,increased hepatocellular carcinoma risk,and higher mortality than hepatitis B virus(HBV)mono-infection.Most countries lack high-quality HDV prevalence data,and the collection techniques employed often bias published data.In recent meta-analyses,HDV prevalence in HBsAg-positive patients reaches 5%-15%and is even significantly higher in endemic areas.Since HBV vaccination programs were implemented,HDV prevalence has decreased among younger populations.However,owing to immigrant influx,it has increased in some Western countries.The current practice of HDV screening in HBsAg-positive individuals is stepwise,based on physician’s discretion,and limited to at-risk populations and may require numerous visits.Double reflex testing,which includes anti-HDV testing in all HBsAg-positive individuals and then HDV RNA testing for anti-HDV-positive ones,is uncommon.Reflex testing can identify more HDV infection cases and link identified patients to further care and follow-up.Moreover,laboratory-based double reflex screening is less biased than physician-led testing.Therefore,health-care providers should learn about reflex testing,and federal and provincial hepatitis control programs should implement laboratory-based double reflex testing to obtain reliable HDV prevalence estimates.The test’s cost-effectiveness depends on the number of HBV-positive patients screened to identify one HDV-positive patient.Such testing may be viable in areas with low HBsAg but high HDV prevalence.However,its economic impact on areas with low HDV prevalence needs further study.

Acute hepatitis B or exacerbation of chronic hepatitis B-that is the question

Hepatitis B virus (HBV) infection constitutes a serious global health problem. In countries with intermediate or high endemicity for HBV, exacerbations of chronic hepatitis B may be the first presentation of HBV infection. Some of these patients may be diagnosed mistakenly as having acute hepatitis B. Accurate diagnosis in these cases is very important for deciding whether to start treatment or not, because acute hepatitis B does not require therapy, while exacerbation of chronic hepatitis may benefit from it. Clinical and routine laboratory findings cannot help distinguishing between these two conditions. Therefore, several assays have been proposed for this purpose during the last few years. The presence of high levels of anti-HBe antibodies, HBsAg and HBV DNA are typical of chronic disease, whereas high titers of IgM anti-HBc, together with their high avidity index, characterize acute HBV infection. Starting from the description of a patient with acute hepatitis B-who recently came to our observation-we critically review the currently available assays that may help distinguishing between the different conditions and lead to the optimal management of each patient.

Community-based cross-sectional seroprevalence study of hepatitis A in Bangladesh

AIM： TO elucidate the age-distribution of anti-hepatitis A virus （HAY） seroprevalence across different socioeconomic status （SES） categories in Bangladesh which, despite scarce data, is generally deemed to have high endemicity. METHODS： Blood samples of 818 subjects from a stratified samp#e of schools and hospitals, comprising different age categories and SES were collected. They were assayed for total anti-HAV antibodies. Social and medical history data were obtained using a questionnaire. RESULTS： Overall anti-HAV seroprevalence was 69.6%, increasing with age from 1-5 years （40.4%） to 〉 30 years （98.4%）. Seroprevalence was lowest （49.8%） in the high SES group and highest （96.5%） in the rural lower-middle SES group. Among subjects aged 6-20 years, anti-HAV seroprevalence was lowest in urban private school children （43.0%）, followed by urban government school children （76.2%） and rural school children （96.5%） （P 〈 0.01）. Within the high SESgroup, anti-HAV seroprevalence was 32.3% in subjects 〈 10 years and 51.7% in those aged 11-20 years. Until now Bangladesh has been deemed to have high endemicity for HAV. CONCLUSION： The transition from high to intermediate HAV endemicity may be underway; high SES adolescents and adults remain particularly at risk of symptomatic illness. Preventive measures need consideration.

Mutations in surface and polymerase gene of chronic hepatitis B patients with coexisting HBsAg and anti-HBs

AIM： To investigate the clinical significance and presence of mutations in the surface （S） and overlapping polymerase gene of hepatitis B patients with coexisting HBsAg and anti-HBs. METHODS： Twenty-three patients with chronic hepatitis B were studied. Of the 23 patients, i i were both positive for hepatitis B virus （HBV） surface antigen （HBsAg） and antibody to HBV surface antigen （anti-HBs）, 12 were negative for anti-HBs while positive for HBsAg. DNA was extracted from 200 μL serum of the patients. Nucleotide of the surface and overlapping polymerase gene from HBV-infected patients was amplified by PCR, and the PCR products were sequenced. RESULTS： Forty-one mutations were found within the surface gene protein of HBV in 15 patients （10 with coexisting HBsAg and anti-HBs）. Six （14.6%） out of 41 mutations were located at ＂α＂ determinant region in 5 patients （4 positive for HBsAg and anti-HBs）. Eleven mutations （26.8%） occurred in the downstream or upstream of ＂α＂ determinant region. Lamivudine （LMV）- selected mutations were found in three patients who developed anti-HBs, which occurred in amino acid positions （196, 198, 199） of the surface protein and in YMDD motif （M204I/V） of the polymerase protein simultaneously. Presence of these mutations did not relate to changes in ALT and HBV DNA levels.CONCLUSION： Besides mutations in the ＂α＂ determinant region, mutations at downstream or upstream of the ＂α＂ determinant region may contribute to the development of anti-HBs. These mutations do not block the replicating competency of HBV in the presence of high titer of anti-HBs.

The Paper Symposium on PLC VIRAL HEPATITIS（HBV AND HCV）BACKGROUND IN CHINESE PATIENTS WITH HEPATOCELLULAR CARCINOMA

Antibody to hepatitis C virus (AntiHCV) was detected using antiHCV EIA (Abbott Kit) in the sera of Chinese patients with hepatocellular carcinoma (HCC), acute hepatitis, chronic hepatitis and blood donors, the positive rates being 10.4% (61/586),11. 8% (10/85),19.2% (44/229), ana 1. 9% (3/160) respectively. HBV DNA was detected by polymerase chain reaction (PCR) in sera from 61 HCC patients with positive antiHCV, the positive rate for HBV DNA being 55.7% (34/61),which was lower than those with negative antiHCV (78.7%) , 413/525). These results indicate that in Chuia the role of HBV infection in the causation of HCC seems to be more important than that of HCV infection.

Neutralization activity of influenza A virus humanized antibodies against new subtypes of influenza viruses

Antibodies are ideal for controlling the influenza A virus,but their effect on newly emerging strains is unclear.Here,we assessed the neutralization activity of the humanized monoclonal antibodies(mAbs)F10,H98 and H40 against circulating influenza viruses(H5N1,H1N1,H3N2 and H7N7 and new subtypes viruses H5N6 and H7N9).The results showed that all the three humanized mAbs(F10,H98 and H40)displayed different degrees of virus neutralization activities when encountered with different subtypes of influenza viruses.Remarkably,the humanized monoclonal antibody F10 produced higher and broader neutralization titers(range 25–1.56μg/ml)than those of the other two humanized mAbs(H98(range 50–3.12μg/ml),H40(range 50–5.56μg/ml))to against the viruses H5N1,H1N1,H3N2,H7N7,H5N6 and H7N9.This mAb may represent a new class of heterosubtypic neutralizing humanized mAb that could replace vaccines and chemical drugs.

Evaluate the prevalence and trend of hepatitis B and hepatitis C in Nahavand: west of Iran, 2013–2017

Viral hepatitis is a global threat to public health and one of the leading causes of death worldwide.Often,acute viral cases in children and adults are associated with viral hepatitis A,B,C,D and E,or co-infection with two types of hepatitis.Infection with these viruses is a global health problem and continuous efforts are in place to identify infected people through targeted screening,preventing new infections through vaccination,monitoring and treating people at risk for complications of all types of hepatitis.The aim of this study was to determine the evaluate the prevalence and trends of hepatitis B and C infection in the Nahavand city during 5 consecutive years(2013–2017).The total number of patients with hepatitis B and C was 141 persons from March 2013 to March 2017,of these,101 had hepatitis B,and 40 had hepatitis C.The prevalence of hepatitis B and C was higher in men than women.The percentage frequency hepatitis B in the city in the last five years was 0.05 percent.11 cases(10.89%)pregnant women and Six cases(5.9%)receiving blood(blood transfusions)in Hepatitis B was observed.the prevalence of hepatitis C was 0.2%at the end of 2017.The study on the cause of hepatitis C in Nahavand has shown that 21(52.5%)of the total of 40 people were infected with addiction.The interesting point in this report is that according to reports from viral hepatitis testing questionnaires,24 of 101 people with type B hepatitis have 23.7%of people with a history of complete vaccination of hepatitis B and one person(0.9%)had incomplete vaccination.A significant relationship was found between the level of education and the prevalence of hepatitis(P=0.005).

Murine antibody against E2 can capture hepatitis C virus in vitro

Objective To find neutralizing antibody candidates against hepatitis C virus (HCV) infection.Methods We constructed two eukaryotic expression vectors which contained the E1 and E2 gene of HCV, and detected their expression in mammalian cells with transient expression. BALB/c mice were given subculaneous injections of constructed vectors combined with the IL-2 gene intraepidermally and evaluated for induced humoral immune responses by enzyme-linked immunosorbent assay (ELISA). We used an antibody-virus interaction assay to analyze the interaction of the antisera and HCV viral particles in vitro.Results Anti E1 and anti-E2 antisera were obtained from immunized mice. The serum of mice immunized with the E2 gene immunoprecipitated the HCV isolate in source serum and reacted with the isolates unrelated to the original one.Conclusions Anti-E2 antibody in induced mice can cross-reactively capture HCV particles, highlighting the possibility of generating broadly reactive anti-E2 antibodies.

A protective human antibody against respiratory syncytial virus by targeting a prefusion epitope across sites IV and V of the viral fusion glycoprotein

Respiratory syncytial virus(RSV)is one of the leading pathogens that cause lower respiratory tract infections in infants and the elderly.Passive immunoprophylaxis with monoclonal antibody(mAb)has been approved to prevent morbidity and mortality from RSV infection in infants.Here we report the isolation of two neutralizing mAbs against RSV from convalescent children by prefusion form of fusion(F)glycoprotein as bait.One mAb RV11 exhibited good potency in neutralization of RSV strains from both A and B subtypes in cell-based assay,and protected mice from RSV infection in vivo.An RV11 escape mutant was identified,which contains an S443P mutation in F protein.Crystal structure showed the RV11 bound to a conserved prefusion epitope across the antigenic sites IV and V of the F glycoprotein.RV11 showed a strong synergistic effect when combined with two RSV antivirals,an F-targeting small molecular inhibitor ziresovir and a siteØneutralizing mAb D25(the parental mAb for nirsevimab).The study extended our knowledge to the neutralizing and protective epitopes of RSV,and the mAb RV11 deserves further development for clinical translation.