Efficacy of novel recombinant fowlpox vaccine against recent Mexican H7N3 highly pathogenic avian influenza virus

Since 2012, H7N3 highly pathogenic avian influenza (HPAI) has produced negative economic and animal welfare impacts on poultry in central Mexico. In the present study, chickens were vaccinated with two different recombinant fowlpox virus vaccines (rFPV-H7/3002 with 2015 H7 hemagglutinin [HA] gene insert, and rFPV-H7/2155 with 2002 H7 HA gene insert), and were then challenged three weeks later with H7N3 HPAI virus (A/chicken/Jalisco/CPA-37905/2015). The rFPV-H7/3002 vaccine conferred 100% protection against mortality and morbidity, and significantly reduced virus shed titers from the respiratory and gastrointestinal tracts. In contrast, 100% of sham and rFPV-H7/2155 vaccinated birds shed virus at higher titers and died within 4?days. Pre- (15/20) and post- (20/20) challenge serum of birds vaccinated with rFPV-H7/3002 had antibodies detectable by hemagglutination inhibition (HI) assay using challenge virus antigen. However, only a few birds (3/20) in the rFPV-H7/2155 vaccinated group had antibodies that reacted against the challenge strain but all birds had antibodies that reacted against the homologous vaccine antigen (A/turkey/Virginia/SEP-66/2002) (20/20). One possible explanation for differences in vaccines efficacy is the antigenic drift between circulating viruses and vaccines. Molecular analysis demonstrated that the Mexican H7N3 strains have continued to rapidly evolve since 2012. In addition, we identified in silico three potential new N-glycosylation sites on the globular head of the H7 HA of A/chicken/Jalisco/CPA-37905/2015 challenge virus, which were absent in 2012 H7N3 outbreak virus. Our results suggested that mutations in the HA antigenic sites including increased glycosylation sites, accumulated in the new circulating Mexican H7 HPAIV strains, altered the recognition of neutralizing antibodies from the older vaccine strain rFPV-H7/2155. Therefore, the protective efficacy of novel rFPV-H7/3002 against recent outbreak Mexican H7N3 HPAIV confirms the importance of frequent updating of vaccines seed strains for long-term effective control of H7 HPAI virus.     

加强医学生实验室生物安全意识浅析[*基金项目：国家自然科学基金(编号：81601394, 81871736)；广东省中医药科研项目(20192048)；呼吸疾病国家重点实验室开放课题(编号：SKLRD-OP-201803, SKLRD-OP-201809)。 ①广州医科大学第一附属医院 呼吸疾病国家中调实验室 广州 510120②广州呼吸健康研究院 广州 510120 # 通讯作者 ]

实验室的安全教育是科研工作者必不可少的一部分,医学生作为特殊的科研人员,因为肩负着救死扶伤的使命,导致他们实验室的工作经验相对较少,不重视实验室的安全教育,成为生物安全问题的易发人群。本文首先阐述医学生实验室安全意识亟待提高的现状,进而从开展生物安全教育、注重实验室管理和实验室技术人员培训、开展实验室生物安全课程及采用网络技术与射频识别(RFID)技术相结合的生物安全监督系统等方面加强医学生实验室安全意识,以期减少医学生发生生物安全事故。     

Protection of White Leghorn chickens by recombinant fowlpox vector vaccine with an updated H5 insert against Mexican H5N2 avian influenza viruses

Despite decades of vaccination, surveillance, and biosecurity measures, H5N2 low pathogenicity avian influenza (LPAI) virus infections continue in Mexico and neighboring countries. One explanation for tenacity of H5N2 LPAI in Mexico is the antigenic divergence of circulating field viruses compared to licensed vaccines due to antigenic drift. Our phylogenetic analysis indicates that the H5N2 LPAI viruses circulating in Mexico and neighboring countries since 1994 have undergone antigenic drift away from vaccine seed strains. Here we evaluated the efficacy of a new recombinant fowlpox virus vector containing an updated H5 insert (rFPV-H5/2016), more relevant to the current strains circulating in Mexico. We tested the vaccine efficacy against a closely related subcluster 4 Mexican H5N2 LPAI (2010 H5/LP) virus and the historic H5N2 HPAI (1995 H5/HP) virus in White Leghorn chickens. The rFPV-H5/2016 vaccine provided hemagglutinin inhibition (HI) titers pre-challenge against viral antigens from both challenge viruses in almost 100% of the immunized birds, with no differences in number of birds seroconverting or HI titers among all tested doses (1.5, 2.0, and 3.1 log₁₀ mean tissue culture infectious doses/bird). The vaccine conferred 100% clinical protection and a significant decrease in oral and cloacal virus shedding from 1995 H5/HP virus challenged birds when compared to the sham controls at all tested doses. Virus shedding titers from vaccinated 2010 H5/LP virus challenged birds significantly decreased compared to sham birds especially at earlier time points. Our results confirm the efficacy of the new rFPV-H5/2016 against antigenic drift of LPAI virus in Mexico and suggest that this vaccine would be a good candidate, likely as a primer in a prime-boost vaccination program.     

Hematotoxicity and genotoxicity evaluations in Swiss mice intraperitoneally exposed to Bacillus thuringiensis (var kurstaki) spore crystals genetically modified to express individually Cry1Aa,Cry1Ab,Cry1Ac,or Cry2Aa

Bacillus thuringiensis (Bt) has been widely used in foliar sprays as part of integrated pest management strategies against insect pests of agricultural crops. Since the advent of genetically modified plants expressing Bt δ‐endotoxins, the bioavailability of Cry proteins has increased, and therefore for biosafety reasons their adverse effects should be studied, mainly for nontarget organisms. We evaluated, in Swiss mice, the hematotoxicity and genotoxicity of the genetically modified strains of Bt spore crystals Cry1Aa, 1Ab, 1Ac, or 2Aa at 27 mg/kg, and Cry1Aa, 1Ab and 2Aa also at 136 and 270 mg/kg, administered with a single intraperitoneal injection 24 h before euthanasia. Controls received filtered water or cyclophosphamide. Blood samples collected by cardiac puncture were used to perform hemogram, and bone marrow was extracted for the micronucleus test. Bt spore crystals presented toxicity for lymphocytes when in higher doses, which varied according to the type of spore crystal studied, besides promoting cytotoxic and genotoxic effects for the erythroid lineage of bone marrow, mainly at highest doses. Although the profile of such adverse side effects can be related to their high level of exposure, which is not commonly found in the environment, results indicated that these Bt spore crystals were not harmless to mice. This suggests that a more specific approach should be taken to increase knowledge about their toxicological properties and to establish the toxicological risks to nontarget organisms. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 970–978, 2016.     

Efficacy of recombinant Marek’s disease virus vectored vaccines with computationally optimized broadly reactive antigen (COBRA) hemagglutinin insert against genetically diverse H5 high pathogenicity avian influenza viruses

The genetic and antigenic drift associated with the high pathogenicity avian influenza (HPAI) viruses of Goose/Guangdong (Gs/GD) lineage and the emergence of vaccine-resistant field viruses underscores the need for a broadly protective H5 influenza A vaccine. Here, we tested experimental vector herpesvirus of turkey (vHVT)-H5 vaccines containing either wild-type clade 2.3.4.4A-derived H5 inserts or computationally optimized broadly reactive antigen (COBRA) inserts with challenge by homologous and genetically divergent H5 HPAI Gs/GD lineage viruses in chickens. Direct assessment of protection was confirmed for all the tested constructs, which provided clinical protection against the homologous and heterologous H5 HPAI Gs/GD challenge viruses and significantly decreased oropharyngeal shedding titers compared to the sham vaccine. The cross reactivity was assessed by hemagglutinin inhibition (HI) and focus reduction assay against a panel of phylogenetically and antigenically diverse H5 strains. The COBRA-derived H5 inserts elicited antibody responses against antigenically diverse strains, while the wild-type-derived H5 vaccines elicited protection mostly against close antigenically related clades 2.3.4.4A and 2.3.4.4D viruses. In conclusion, the HVT vector, a widely used replicating vaccine platform in poultry, with H5 insert provides clinical protection and significant reduction of viral shedding against homologous and heterologous challenge. In addition, the COBRA-derived inserts have the potential to be used against antigenically distinct co-circulating viruses and future drift variants.     

病原微生物实验室Ⅱ级生物安全柜防护性能评价

目的评价病原微生物实验室Ⅱ级生物安全柜的防护性能。方法采用安德森采样器采样方法和通过相关仪器,以粘质沙雷菌气溶胶为防护对象进行Ⅱ级生物安全柜防护性能评价。结果所评价的36台Ⅱ级生物安全柜下降气流的平均合格率为91.7%,流入气流合格率为43.7%,气流模型合格率为43.9%。人员保护合格率为72.2%,样品保护合格率为88.9%,交叉污染合格率为88.9%。结论所测试的Ⅱ级生物安全柜存在较大的气溶胶泄漏风险,对实验操作人员保护性能较差。     

用粘质沙雷菌试验评价Ⅱ级生物安全柜的研究

目的改进完善Ⅱ级生物安全柜生物测试的方法,观察两种指示微生物的空气生物学特性。方法采用改良美国NF-49标准方法,以粘质沙雷菌为指标菌检测生物安全柜防护性能。结果枯草杆菌黑色变种芽孢经过porton采样器冲击30 m in,其相对存活率只有37%;而粘质沙雷菌经30 m in冲击,其相对存活率为88%。枯草杆菌黑色变种芽孢经30 m in雾化,其相对存活率为53%;粘质沙雷菌雾化30 m in,其相对存活率为89%。实验环境中粘质沙雷菌本底检测结果菌落数均为0,粘质沙雷菌在自然界空气中不是优势菌株,不会对检测产生干扰。两台生物安全柜在不同风速下防护性能检测结果全部合格且与该安全柜出厂检测结果一致。结论粘质沙雷菌具有良好的雾化和冲击耐受性,受检的安全柜的人员、样品和环境防护作用合格,本研究建立的检测验证方法灵敏性和重复性与美国标准(NF-49)一致。     

护士配置化疗药物时不使用生物安全柜的根源分析与对策

目的:分析临床护士不使用生物安全柜的根本原因,为提高其使用率提出对策。方法:针对我院血液科病房护士配置化疗药物过程中不使用生物安全柜的现况,采用根源分析法进行深入分析。结果:原因包括护理人员、政策、工作环境、资源环境4个方面。结论:可以通过规范化疗药物操作流程、开展职业防护知识在职培训、加强化疗药物职业防护管理等方式促进护士使用生物安全柜。     

Evaluation of medicinal plant hepatotoxicity in co-cultures of hepatocytes and monocytes

Non-parenchymal cells might play an important role in the modulation of xenobiotic metabolism in liver and its pharmacological and toxicological consequences. Therefore, the role of cell-to-cell interactions in herbal induced liver toxicity was investigated in monocultures of cells from the human hepatocyte cell line (HepG2) and in co-cultures of cells from the HepG2 cell line and cells from the human monocyte cell line (THP1). Cells were treated with various concentrations (1-500 microg ml(-1)) of extracts of Pistacia palaestina, Juglans regia and Quercus ithaburensis for 24 h. Extracts from Cleome droserifolia, a known toxic plant, were taken as positive control. In the co-culture system, toxic effects were observed after exposure to extracts of Pistacia palestina and C. droserifolia. These two extracts significantly reduced by cell viability as measured the MTT test and the LDH assay. Whereas in hepatocyte cultures, only extracts of C. droserifolia were found to affect the cell viability. The production levels of albumin from hepatocytes were not affected by treatment with plant extracts in both culture systems. It seems that the observed reduction in cell viability after exposure to extracts of P. palestina in co-cultures but not in monocultures is a result of monocyte-derived factors. The use of liver cell co-cultures is therefore a useful approach to investigate the influence of intercellular communication on xenobiotic metabolism in liver.     

新型冠状病毒肺炎疫情下重庆市医疗机构临床实验室生物安全现状调查

目的了解新型冠状病毒肺炎疫情下重庆市医疗机构临床实验室生物安全现状。方法于2020年2月8-15日,对重庆市42家新型冠状病毒肺炎定点救治医院临床实验室发放问卷调查,调查内容包括实验室基本情况、实验室生物安全设施设备配置、实验室个人防护用品配置、实验室未开展新型冠状病毒核酸检测原因、实验室生物安全培训情况等。结果在规定时间内收到26家实验室有效回报,26家定点医疗机构中二级和三级医疗机构各占50.0%。所有实验室均为已备案的生物安全二级实验室;无门禁装置实验室1家(3.8%),无自动可关闭门实验室2家(7.7%),无负压条件实验室22家(84.6%);自然通风实验室15家(57.7%);4家(13.4%)实验室安全设备未年检;6家(23.1%)实验室没有防护服储备。10家未开展新型冠状病毒核酸检测的实验室中有7家(70.0%)原因为三级生物安全防护用品缺乏。26家实验室均及时组织了人员培训,1家(3.8%)实验室组织了针对性的操作演练。结论实验室应加强安全设施设备的投入和监管,加大应急防护物资的储备,建立健全有效的生物安全培训体系,进一步提高临床验室应对新发、突发传染病的生物安全管理能力。