Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system

H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

Preparation of Monoclonal Antibodies against Hemagglutinin of Avian Influenza Virus H9 Subtype by Plasmid Immunization

Avian influenza has caused enormous economic losses to poultry industry. To develop kits for rapid diagnosis of avian influenza virus （AIV） H9 subtype, 8-week-old Balb/c mice were administered with pcDNA3.1 （ ＋ ） carrying hemagglutinin （HA） gene of AIV H9 subtype. After cell fusion, one positive hybridoma cell strain was screened out by hemagglutination inhibition assay （ HI ）, and another positive hybddoma call strain was screened out by ELISA. After subcloning 3 times, the two cell strains could still secret antibodies against the HA of AIV H9 subtype. The mono- clonal antibodies did not react with Newcastle disease virus, AIV H5 subtype and duck adenovirus A. Their subtypes were IgG2b with kappa light chain. These two hybridoma cell strains may play an important role in rapid diagnosis and early-warning surveillance of AIV H9 subtype.

Development of H5 subtype-specific monoclonal antibodies (MAb) and MAb-based assays for rapid detection of H5 avian influenza

Avian influenza (AI) virology surveillance is the most important method to monitor AI virus (AIV) in poultry so as to effectively prevent and control AI outbreaks. Monoclonal antibodies (MAb)-based assays are highly sensitive and specific for AIV detection, and much practical and economic for test-in-field or onsite. Many such assays have been developed and are still in developing since the H5N1 highly pathogenic AI (HPAI) outbreaks occurred in South East Asia in 2003. A MAb-based dot-enzyme-linked immunosorbent assay (ELISA) has been developed in our lab during late 1990s and early 2000s. Meanwhile, AIV H7 and H5 subtype specific-MAbs have been successfully developed in our laboratory to enhance the Dot-ELISA and other MAb-based assays for AIV detection. Production and purification of the H7 and H5 MAbs were made to provide essential reagents for Dot-ELISA and other immunoassays, and the current development of a novel Biosensor technique for rapid detection of AIV from clinical and field specimens.

Development and Characterization of Monoclonal Antibody Specific to Nuclear Protein of Avian Influenza Virus Type A

Five monoclonal antibodies（Mabs） to nuclear protein of avain influenza virus（AIV） were developed by syncretizing SP 2/0 and the spleen cells from BALB of mice immuized with H9 subtype AIV. Specificity of these Mabs were identified by immunofluorescent assay（IFA） and enzyme linked immunosorbent assay （ELISA）. These five Mabs which were named as AIV-NP-2C3, AIV-NP-6A5, AIV-NP-3 H9, AIV-NP-7B4, AIV-NP-2H4 could react with all viruses of AIV-H9 strains in tests. The result of Western blotting showed that only the 60 ku protein antigen of AIV-H9 could be recognized by the Mabs but never recognized by New castle disease virus, REV and infectious bursa disease virus. The result of preliminary application showed that avian influenza viruses could be deetected bv Mabs in IFA and ELISA. All these Mabs will probably play important roles in preventing and monitoring avian influenza viruses.

Cross-neutralizing Anti-hemagglutinin Antibodies Isolated from Patients Infected with Avian Influenza A(H5N1) Virus

Objective To recover broad-neutralizing monoclonal antibodies(Bn Abs)from avian influenza A(H5N1)virus infection cases and investigate their genetic and functional features.Methods We screened the Abs repertoires of expanded B cells circulating in the peripheral blood of H5N1 patients.The genetic basis,biological functions,and epitopes of the obtained Bn Abs were assessed and modeled.Results Two Bn Abs,2-12 D5,and 3-37 G7.1,were respectively obtained from two human H5N1 cases on days 12 and 21 after disease onset.Both Abs demonstrated cross-neutralizing and Ab-dependent cellular cytotoxicity(ADCC)activity.Albeit derived from distinct Ab lineages,i.e.,V^H1-69-D2-15-JH^4(2-12D5)and V^H1-2-D3-9-JH^5(3-32 G7.1),the Bn Abs were directed toward CR6261-like epitopes in the HA stem,and HA2 I45 in the hydrophobic pocket was the critical residue for their binding.Signature motifs for binding with the HA stem,namely,IFY in VH1-69-encoded Abs and LXYFXW in D3-9-encoded Abs,were also observed in 2-12D5 and 3-32 G7.1,respectively.Conclusions Cross-reactive B cells of different germline origins could be activated and re-circulated by avian influenza virus.The HA stem epitopes targeted by the Bn Abs,and the two Ab-encoding genes usage implied the VH1-69 and D3-9 are the ideal candidates triggered by influenza virus for vaccine development.

Monitoring Report of Maternal Antibody of Broiler Avian Influenza Virus H5 Subtype Re-8 Strain

[ Objective ] The paper was to prevent the occurrence of broiler avian influenza virus HS subtype Re-8 strain effectively in the breeding process of broilers. [Method] The maternal antibodies of broilers in Beijing Baochen Hongwang farm were monitored. According to the disappearance law of maternal antibody, the optimal immune time of broiler avian influenza virus H5 subtype Re-8 strain was determined. [ Result] The maternal antibody level of 2-day-old broilers was relatively high, concentrated at 6 log2 -9 log2, and the antibody positive rate was 100%. The maternal antibody level of 8-day-old broilers concentrated at 4 log2 -6 log2, and the antibody positive rate was 100%. The maternal antibody level of 17-day-old broilers concentrated at 0 log2 -3 log2 , and the antibody positive rate was 0. The average maternal antibody level of 24 - 37 days old broilers was 〈 1 log2, and the antibody positive rate was 0. [ Conclusion ] Although the av- erage maternal antibody level of 8-day-old broilers was higher than 5 log2 , 20% of chickens was 4 log2, and maternal antibody could not protect the flock completely. Therefore, the best primary immunization day age of chicks against avian influenza virus was 8 - 10 days of age.

Suppression of Highly Pathogenic Avian Influenza A/H5N1 Infection Using Migratory Antibody Passed from Mother to Chick

Avian influenza is the most contagious disease not only in poultry, but also in humans. Avian influenza in humans occurs mainly in Southeast Asia, but no human-to-human pandemic has occurred. Meanwhile, outbreaks of avian influenza in poultry occur on a global scale and cause a large economic loss. Migration antibodies passed from mother birds via eggs are said to be an important component of the immune system that protects birds from infection. Thus, the immunity status of mother birds can determine the ability of offspring to defend against infection. In this study, we investigated the presence of anti-avian influenza virus antibody in chickens hatched on a poultry farm in Indonesia and examined the involvement of migratory antibodies in protecting against virus infection by infectious experiments of highly pathogenic avian influenza in chickens. Blood was collected from randomly selected chicks, and antibodies against avian influenza virus were evaluated in all birds. Since these young birds had no history of vaccination, the antibodies were deemed to have been transferred from the mother birds. The enzyme-linked immunosorbent assay antibody titer in each bird varied. Infection of these birds with highly pathogenic avian influenza virus A/H5N1 intra-nasally resulted in a high mortality rate in chicks with low antibody titers but a low mortality rate in chicks with high antibody titers. These findings indicate that migratory antibody prevented highly pathogenic avian influenza A/H5N1 infection in chicks, suggesting that such a preventive effect could also be expected with outdoor natural infection.

H5N1亚型禽流感病毒神经氨酸酶蛋白在昆虫细胞中的表达与鉴定

研究旨在利用昆虫细胞-杆状病毒表达系统制备H5N1亚型禽流感病毒(AIV)的神经氨酸酶(NA)蛋白。试验为获得具有良好反应原性的NA蛋白,将H5N1亚型AIV(DK/YN/S4469/2022)密码子优化后的N1基因插入载体pFastBac1,构建的重组转移载体pFastBac1-N1转化至DH10Bac感受态细胞,经过蓝白斑筛选获得阳性重组杆粒rBacmid-N1,然后将重组杆粒转染至sf9昆虫细胞,获得N1亚型重组杆状病毒。结果显示:N1重组蛋白在sf9昆虫细胞中正确表达,并且该重组蛋白具有良好的反应原性,能够与N1蛋白单克隆抗体3F3发生特异性反应,其仅能识别N1亚型鸡血清,特异性较好。研究成功制备了N1重组蛋白,为NA蛋白表达方法提供参考并为临床血清样品的N1抗体检测方法的建立奠定基础。

Preparation of Anti-Idiotypic Antibody against Avian Influenza Virus Subtype H9

To generate monoclonal anti-idiotypic antibodies(mAb2)against avian influenza virus subtype H9(H9 AⅣ), BALB/c mice were immunized with purified chicken anti-H9-AⅣ IgG and the splenocytes of immunized mice were fused with myeloma cells NS-1.Hybridoma cells were screened by indirect enzyme-linked immunosorbent assays with both chicken and rabbit anti-H9-AⅣ IgG as coating antigens.One hybridoma cell clone secreting monoclonal antibody against idiotypes shared by both chicken and rabbit anti-H9-AⅣ IgG was established.Experiments demonstrated the mAb2 was able to inhibit the binding of hemagglutinin to anti-H9-AⅣ IgG and to induce chickens to generate hemagglutination inhibition antibodies,indicating this anti-species-sharing-idiotypic antibody bore the internal image of hemagglutinin on avian influenza virus.Cellular & Molecular Immunology.2005;2(2): 155-157.

LabVIEW-based impedance biosensing system for detection of avian influenza virus

In order to detect the multiple avian influenza viruses(AIVs)rapidly,specifically and sensitively,a LabVIEW and microelectrode array-based impedance biosensor was developed and demonstrated.A laptop with LabVIEW software was used to generate excitation signals at different frequencies with an audio card and measure the impedance of target viruses through a data acquisition card.The audio card of the laptop was used as a function generator,while a data acquisition card was used for data communication.A virtual instrument was programmed with LabVIEW to provide a platform for impedance measurement,data processing,and control.Six interdigitated microelectrodes were placed at the bottom of six wells on a microplate to form six sensors for different AIVs and controls.Then,AIV specific ligands were immobilized on the microelectrode surface to capture target viruses.To enhance the sensitivity,AIV specific aptamers conjugated gold nanoparticles and thiocyanuric acid were employed to form a network structure and used as an amplifier.Results of the measured impedance were compared with a commercial IM6 impedance analyzer,and the error was less than 5%.The developed biosensor was portable with the sensitivity and specificity for applications to on-site or in-field rapid screening of avian influenza viruses.

检测H6亚型禽流感病毒的双抗体夹心ELISA方法的建立及初步应用

为建立快速检测H6亚型禽流感病毒的血清学方法,试验利用前期制备的两株抗H6亚型禽流感病毒血凝素单克隆抗体,建立检测H6亚型禽流感病毒的双抗体夹心ELISA方法,并进行特异性、灵敏度、稳定性试验以及对活禽市场采集的48份咽拭子样品的检测效果。结果显示:该ELISA方法只与H6亚型禽流感病毒反应,而与H1、H3、H4、H5、H7、H9、H10、H12等其他亚型禽流感病毒,血清4型禽腺病毒、血清8b型禽腺病毒、血清3型鸭腺病毒、传染性支气管炎病毒、新城疫病毒、鹅星状病毒、小鹅瘟病毒、传染性法氏囊病病毒以及禽白血病病毒均无交叉反应;该ELSIA方法可检测2.32×10^(4)TCID50/mLH6亚型禽流感病毒,批间和批内重复试验变异系数均小于10%;该ELISA方法和RT-PCR方法对活禽市场采集的48份咽拭子样品检测结果一致,进一步检测攻毒鸡的咽拭子显示该方法可有效检测咽拭子中H6亚型禽流感病毒。研究表明,基于两株单克隆抗体建立的检测H6亚型禽流感病毒的双抗体夹心ELISA方法具有特异性强、灵敏度高的特点,适用于H6亚型禽流感病毒感染的临床检测。

Rapid detection of influenza A(H1N1)virus by conductive polymer-based nanoparticle via optical response to virus-specific binding

A recurrent pandemic with unpredictable viral nature has implied the need for a rapid diagnostic technology to facilitate timely and appropriate countermeasures against viral infections.In this study,conductive polymer-based nanoparticles have been developed as a tool for rapid diagnosis of influenza A(H1N1)virus.The distinctive property of a conductive polymer that transduces stimulus to respond,enabled immediate optical signal processing for the specific recognition of H1N1 virus.Conductive poly(aniline-co-pyrrole)-encapsulated polymeric vesicles,functionalized with peptides,were fabricated for the specific recognition of H1N1 virus.The low solubility of conductive polymers was successfully improved by employing vesicles consisting of amphiphilic copolymers,facilitating the viral titer-dependent production of the optical response.The optical response of the detection system to the binding event with H1N1,a mechanical stimulation,was extensively analyzed and provided concordant information on viral titers of H1N1 virus in 15 min.The specificity toward the H1N1 virus was experimentally demonstrated via a negative optical response against the control group,H3N2.Therefore,the designed system that transduces the optical response to the target-specific binding can be a rapid tool for the diagnosis of H1N1.

A quantitative RT-PCR assay for rapid detection of Eurasianlineage H10 subtype influenza A virus

Dear Editor,Influenza A viruses(IAVs)are single-stranded,negative sense RNA viruses.IAV subtype is determined on the basis of the viral surface glycoproteins,hemagglutinin(HA),and neuraminidase(NA).To date,18 HA and 11NA subtypes have been reported(Tong et al.,2012).

桦褐孔菌口服佐剂对禽类疫苗的体液免疫增强作用研究

为了明确桦褐孔菌发酵产物(Inonotus obliquus fermentation product,IOFP)作为禽类疫苗佐剂的适用性,选择商品化禽流感灭活疫苗和鸭坦布苏病毒弱毒活疫苗分别免疫SPF鸡和SPF鸭,并饲喂含0.8%IOFP的饲粮,同时设置饲喂商品化饲粮的对照组。在免疫后不同时间点采集鸡和鸭的外周血,分离血清后分别测定禽流感病毒(avian influenza virus,AIV)特异性血凝抑制(hemagglutinin inhibition,HI)抗体、鸭坦布苏病毒(duck Tembusu virus,DTMUV)特异性抗体及二者中和抗体效价。使用统计学方法评价IOFP对机体体液免疫反应的影响。鸭免疫后28 d使用DTMUV强毒株攻毒,持续检测泄殖腔排毒量,以确定IOFP对DTMUV排毒量的影响。结果显示,IOFP作为口服佐剂能够显著提升AIV、DTMUV疫苗抗体和中和抗体水平,特别是对免疫早期抗体的改善效果尤为显著。此外,添加IOFP还能够减少DTMUV的排毒量,缩短排毒时间。由此可见,IOFP是一种禽类病毒性疫苗普遍适用的口服佐剂,对于缩短免疫“空窗期”、提升疫苗保护效果具有较好的改善作用。

H9N2亚型禽流感病毒多拷贝M2e蛋白单克隆抗体的制备

为制备H9N2亚型禽流感病毒(AIV)多拷贝M2e蛋白单克隆抗体,试验将纯化的3M2e重组蛋白免疫BALB/c小鼠;取免疫小鼠的脾细胞与SP2/0细胞融合,采用间接ELISA筛选出分泌抗体的杂交瘤细胞株;将获得的杂交瘤细胞株腹腔注射BALB/c小鼠制备腹水;采用间接ELISA测定腹水效价,鼠源单克隆抗体亚类鉴定试剂盒检测单克隆抗体腹水,三株单克隆抗体重链亚型均为IgG1;Westernblot鉴定单克隆抗体的特异性;使用IFA鉴定3M2e蛋白在Sf9细胞的表达和检测H9N2亚型AIV在MDCK细胞的感染。结果显示:获得了3株分泌多拷贝M2e抗体的杂交瘤细胞株,分别命名为4C7-B11、4E10-A10和5A12-B5;获得腹水的效价均为1∶1000000;三株单克隆抗体重链亚型均为IgG1;Westernblot鉴定三株单克隆抗体均能与2M2e、3M2e和4M2e原核重组蛋白及在Sf9细胞表达的3M2e发生特异性反应;IFA鉴定结果也显示三株单克隆抗体均能检测3M2e蛋白在Sf9细胞的表达,并且能检测到H9N2亚型AIV在MDCK细胞上的感染,出现特异性的绿色荧光;三株单克隆抗体重链亚型均为IgG1。研究获得了H9N2亚型AIV多拷贝M2e单克隆抗体,可用于Westernblot和IFA鉴定,为靶向M2e蛋白H9N2亚型禽流感疫苗的研究提供特异性的检测工具。

重组禽流感病毒(H5+H7)三价灭活疫苗免疫黄鸡抗体水平分析

H5或H7亚型高致病性禽流感是一种高度致死性传染病,它不仅给养禽业造成了巨大的危害和损失,还威胁着人类的生命健康安全。为了分析重组禽流感病毒(H5+H7)三价灭活疫苗(H5N1 Re-11株+H5N1 Re-12株和H7N9 H7-Re3株)免疫抗体水平,本研究对如皋市内14个养殖场近2万只黄鸡进行重组禽流感病毒三价灭活疫苗肌肉注射,免疫三周后,随机采集420份血液样品进行HI抗体效价检测。结果表明,免疫后的鸡群均无明显不良反应,可以诱导黄鸡产生良好的抗体,检测时具有较高的抗体效价,H5亚型Re-11株平均抗体效价为7.8log2,Re-12株平均抗体效价为8.2log2,H7亚型Re-3株的平均抗体效价为6.8log2,并且免疫抗体合格率均达到70%以上,对黄鸡具有良好的安全性和免疫保护效果,研究结果为有效地控制高致病性禽流感提供参考依据。

Maternal Antibody Protected Chicks from Growth Retardation and Immunosuppression Induced by Early Reticuloendotheliosis Virus Infection

To determine if the maternal antibody from breeders vaccinated with cell culture-adapted reticuloendotheliosis virus （REV） could protect chicks from early REV infection, one-day-old chicks with or without anti-REV maternal antibodies were inoculated with REV, and then their growth rates and antibody titers to Newcastle disease virus （NDV） and avian influenza virus （AIV）, after vaccination with inactivated vaccines, were compared. This study indicated that REV infection could cause growth retardation and severely inhibit immune reactions to inactivated vaccines against NDV and Avian influenza virus （AIV, H9 and H5） in one-day-old broilers without maternal antibodies specific to REV. Maternal antibody from breeders vaccinated with an attenuated REV vaccine effectively protected REV-challenged birds from growth retardation and immunosuppression on antibody reactions to NDV and AIV vaccines. Four weeks after vaccination, the HI titers to NDV, AIV-H9, and AIV-H5 in maternal antibody positive and negative groups were 3.36 ＋- 2.04 versus 1.58± 1.69 （P〈0.01）, 6.27±3.87 versus 0.71 ± 1.60 （P〈0.01）, and 6.72±3.92 versus 0.54± 1.44 （P〈0.01）. Maternal antibodies from breeders vaccinated with REV vaccine could successfully protect chicks from REV infection and effectively prevent REV-induced growth retardation and immunosuppression in antibody responses to NDV and AIV.

Maternal-derived antibodies hinder the antibody response to H9N2 AIV inactivated vaccine in the field

The H9N2 subtype avian influenza virus(AIV)inactivated vaccine has been used extensively in poultry farms,but it often fails to stimulate a sufficiently high immune response in poultry in the field,although it works well in laboratory experiments;hence,the virus still causes economic damage every year and poses a potential threat to public health.Based on surveillance data collected in the field,we found that broilers with high levels of maternal-derived antibodies(MDAs)against H9N2 virus did not produce high levels of antibodies after vaccination with a commercial H9N2 inactivated vaccine.In contrast,specific pathogen-free(SPF)chickens without MDAs responded efficiently to that vaccination.When MDAs were mimicked by administering passively transferred antibodies(PTAs)into SPF chickens in the laboratory,similar results were observed:H9N2-specific PTAs inhibited humoral immunity against the H9N2 inactivated vaccine,suggesting that H9N2-specific MDAs might hinder the generation of antibodies when H9N2 inactivated vaccine was used.After challenge with homologous H9N2 virus,the virus was detected in oropharyngeal swabs of the vaccinated and unvaccinated chickens with PTAs but not in the vaccinated chickens without PTAs,indicating that H9N2-specific MDAs were indeed one of the reasons for H9N2 inactivated vaccine failure in the field.When different titers of PTAs were used to mimic MDAs in SPF chickens,high(HI=12 log2)and medium(HI=log 9 log2)titers of PTAs reduced the generation of H9N2-specific antibodies after the first vaccination,but a booster dose would induce a high and faster humoral immune response even of PTA interference.This study strongly suggested that high or medium titers of MDAs might explain H9N2 inactivated vaccine failure in the field.

禽流感病毒检测方法研究进展

禽流感病毒(AIV)不仅能引起禽类发病和死亡,造成严重的经济损失,部分亚型(H5N1、H7N9等)也能感染人类,严重威胁人类健康。早期检测AIV对于禽流感的高效防控非常重要,有必要开发高特异性、高敏感性、操作简便、快速的检测方法用于AIV早期检测。文章对禽流感病毒的免疫学检测方法、分子生物学检测方法以及生物传感器检测方法进行综述,以期为禽流感病毒的检测提供参考。

甲型肝炎病毒IgM抗体快速检测试剂国家参考品的建立

目的建立甲型肝炎病毒IgM抗体快速检测试剂国家参考品,制订其质量标准,用于该类试剂的质量评价。方法通过对200多份单采浆站收集到的血浆进行初筛,筛选出16份备选样本。经多家实验室协助标定,分析标定结果,确定参考品的组成及其质量标准,并对参考品稳定性进行评估。结果本参考品由10份阴性参考品、1份最低检出限参考品和重复性参考品组成。质量标准为10份阴性参考品符合率(-/-)应为10/10,最低检出限参考品要求1:40稀释时检测阳性,重复性参考品要求1:15稀释时连续检测10次,结果应均为阳性,且显色度均一。稀释血浆应均为HCV、HBV和HIV标志物阴性。参考品在4℃放置3、7 d和反复冻融2次条件下相对比较稳定。结论成功建立甲型肝炎病毒IgM抗体快速检测试剂国家参考品,可用于该类试剂的质量控制及评价。