SEROLOGICAL STUDIES OF SWINE INFLUENZA VIRUSES

1. Cross-neutralization tests with sera from swine recovered from infection with swine influenza indicated the serological identity of 7 strains of swine influenza virus obtained from different sources. 2. Cross-neutralization tests with sera from rabbits, immunized to swine influenza virus, exposed serological differences among the same 7 swine influenza virus strains. Two strains appeared to be serologically similar and were characterized by the ability to produce effective homologous virus-neutralizing sera which were, however, poor or ineffective against the heterologous virus strains. Two other strains were also serologically similar but produced antibodies effective not only against themselves, but against all heterologous strains as well. The remaining 3 strains were intermediate in their ability to produce heterologous virus-neutralizing antibodies. 3. The human influenza viruses included, especially strains WS and Oakham, were most effectively differentiated serologically from the swine influenza viruses by rabbit antisera. 4. The suggestion is advanced that swine antisera express the antigenic composition of the swine influenza viruses, while rabbit antisera reflect either their antigenic arrangement or the arrangement of the components responsible for their mouse pathogenicity. On this interpretation the 7 strains of swine influenza virus studied would be considered to have similar antigenic compositions but differing antigenic structures. 5. The serological differences among strains of the swine influenza virus, detectible by rabbit antisera, are probably of no practical significance so far as the natural disease, swine influenza, is concerned.     

Antigenic variants of rabies virus

Antigenic variants of CVS-11 strain of rabies virus were selected after treatment of virus populations with monoclonal antibodies directed against the glycoprotein antigen of the virus. These variants resisted neutralization by the hybridoma antibody used for their selection. Two independently mutating antigenic sites could be distinguished when five variants were tested with nine hybridoma antibodies. The frequency of single epitope variants in a cloned rabies virus seed was approximately 1:10,000. Animals were not or only partially protected when challenged with the parent virus or with another variant, but were fully protected against challenge with the virus used for immunization. Variants were also detected among seven street viruses obtained from fatal cases of human rabies. Animals immunized with standard rabies vaccine were protected against challenge with some but not all street rabies variants. A comparative antigenic analysis between vaccine strain and challenge virus by means of monoclonal antiglycoprotein antibodies showed a slightly closer degree of antigenic relatedness between vaccine and challenge strain in the combinations where vaccination resulted in protection. It remains unknown, however, whether these apparently minor antigenic differences in the glycoproteins account for the varying degrees of protection. The results of this study clearly indicate that the selection of vaccine strains and the methods used to evaluate the potency of rabies vaccines need to be revised.     

2012－2016年北京市朝阳区33株风疹病毒分离株基因特征分析

目的 通过对北京市朝阳区疑似风疹病例咽拭子标本进行细胞培养及基因特征分析,了解其分子流行病学特征。 方法 使用Vero/SLAM细胞对2012 — 2016年北京市朝阳区暴发和散发病例的风疹咽拭子标本进行病毒分离,应用反转录–聚合酶链式反应扩增风疹病毒E1基因序列,对扩增产物进行核苷酸序列测定。 使用分子生物信息学软件,将获得风疹病毒毒株核酸序列与世界卫生组织推荐风疹病毒13个基因型的32个参考毒株及16株中国部分省市流行株E1基因739个核苷酸序列进行系统发生树的构建及对比分析。 结果 共分离出33株风疹病毒毒株,其中8株为1E基因型,25株为2B基因型。 1E型风疹流行株分离自2012 — 2013年,2B型风疹流行株分离自2012 — 2016。 2B型流行株组内遗传距离及组间遗传距离均小于1E型流行株的组内遗传距离和组间遗传距离。 结论 2012 — 2016年北京市朝阳区风疹病毒流行优势株为2B基因型,1E基因型正在逐步被2B基因型代替。 2B基因型风疹流行株核酸序列更稳定,并逐渐成为优势基因型。      

RUBELLA VIRUS CARRIER CULTURES DERIVED FROM CONGENITALLY INFECTED INFANTS

Spontaneous rubella carrier cultures derived from tissues of infants with congenital rubella were studied in an attempt to elucidate a possible mechanism for viral persistence observed in these infants. Chronically infected cells were found to have a reduced growth rate and the cultures appeared to have a shortened life span. The rubella carrier state was not dependent on serum inhibitors or rubella antibodies. Virtually every cell in the carrier population was found to be producing virus. The carrier cultures could not be cured by rubella antibodies. The rubella-infected cells were resistant to superinfection with vesicular stomatitis virus and herpes simplex virus but were susceptible to infection with echovirus 11. The replication of vesicular stomatitis virus was apparently blocked at an intracellular site, for the virus readily adsorbed to the chronically infected cells and entered into an eclipse phase; however no infectious virus developed. No evidence of interferon production by these cells could be obtained. It is postulated that clones of rubella-infected cells in vivo, with properties similar to those in carrier cultures developed in vitro from tissues of in utero infected infants, might explain the observed viral persistence noted in congenital rubella.     

ANTIGENIC RELATIONSHIP OF BRITISH SWINE INFLUENZA STRAINS TO STANDARD HUMAN AND SWINE INFLUENZA VIRUSES : THE USE OF CHICKEN AND FERRET ANTISERA IN RED CELL AGGLUTINATION

The antigenic relationships of Type A (PR 8, WS) and Type B (Lee) human strains and the Shope and British (Cambridge, North Ireland) swine strains were studied by specific antiserum inhibition of chicken red cell agglutination by the influenza virus. The Cambridge and North Ireland strains were found to be closely related to the Type A strains and differentiated from the Shope virus. The distinctive antigenicity of the Lee strain of Type B was confirmed. Specific antibodies were developed in chickens following single intraperitoneal injections of influenza virus. Inhibition tests yielded results, in the antigenic analysis of the influenza viruses examined, comparable to those obtained with ferret antisera. Specific inhibition of hemagglutination by influenza virus proved an effective method for the study of strain relationships.     

重庆市2011-2016年风疹病毒基因特征分析

目的 通过对重庆市2011-2016年分离的风疹病毒进行基因型别鉴定及系统进化分析,为预防和控制风疹提供分子流行病学依据.方法 收集重庆市2011-2016年风疹病毒核酸检测阳性病原学标本进行病毒分离,通过序列测定鉴定其基因型别;与GenBank中风疹各型别参考毒株及其他省市所获毒株进行进化树构建和遗传距离分析.结果 2011-2013年风疹毒株主要为1E基因型(94/103);2014-2016年主要为2B基因型(50/56),仅2014年有1株2A基因型毒株.重庆株系与其他省市毒株核苷酸同源性1E型为97.63%~99.73%,平均98.90%;2B型为95.77%~99.73%,平均98.30%.系统树上重庆毒株并未与其他省市株系相互隔离.结论 重庆市风疹优势基因型近年已经逐渐由1 E型替代为2B型.重庆市的风疹病毒基因型在不断变化,优势株与其他省市呈共同进化状态.     

Monoclonal antibodies for the rapid diagnosis of respiratory syncytial virus infection by immunofluorescence

Eight separate monoclonal antibodies to the Long strain of respiratory syncytial virus (RSV) were tested for their utility as rapid diagnostic reagents in immunofluorescence. Preliminary screening indicated that all 8 reacted with 11 field strains from three previous local RSV outbreaks and with 4 of 5 additional strains chosen because of their antigenic diversity by neutralization. Two monoclonal antibodies, one each directed against a surface glycoprotein and the nucleocapsid protein, were then compared, singly and combined, with a polyclonal antiserum as diagnostic reagents in 209 consecutive samples submitted to our diagnostic laboratory. Agreement between the two monoclonal antibodies was 100% and between them and the polyclonal serum was 98%. Sensitivity in relation to culture was 96–;98%. Monoclonal antibodies are excellent immunofluorescent diagnostic reagents; antigenic diversity among RSV strains was not an impediment to their use in this study.     

2014-2021年北京市麻疹风疹实验室网络运转情况分析

目的 分析2014—2021年北京市麻疹风疹实验室网络运转状况,综合各项指标评价网络运行质量。方法 汇总2014—2021年北京市麻疹风疹实验室网络病例诊断、病原学分析、病毒基因型、职能考核等结果数据,综合网络运转情况进行统计分析。结果 网络共包括21家实验室,其中市级疾病预防控制中心1家、区级疾病预防控制中心16家、医疗机构4家,各级实验室按职责和检测时限有序分工。2014—2021年网络实验室共检测疑似麻疹或风疹病例血清样本12 229份,麻疹阳性率19.32%,风疹阳性率7.10%;核酸样本8 100份,麻疹阳性率23.72%,风疹阳性率8.63%。麻疹病毒基因型测序1 705株,分型发现H1a基因型1 687株、D8基因型11株、B3基因型2株、疫苗株5株;风疹病毒基因型测序37株,其中1E基因型13株、2B基因型24株。网络每年开展质量控制和技术培训,各实验室职能考核成绩良好。结论 北京市麻疹风疹实验室网络运转良好,并通过持续技术提升提高了实验室诊断敏感性和监测能力,同时通过严格的质量控制保证了实验室数据准确高效,为北京市麻疹消除和风疹防控提供有力的技术保障。     

Serum and CSF antibody levels to herpes simplex type 1, measles and rubella viruses in patients with schizophrenia.

Serum and CSF specimens from 12 schizophrenic patients and 10 non-psychiatric controls were tested for herpes simplex type 1 virus neutralizing antibody and for measles and rubella haemagglutination inhibiting antibodies. There were no significant differences in the distribution of virus antibody titres in serum or CSF specimens between the patients and the controls. The possible aetiological role of viruses or virus-like agents in schizophrenia and some methodological aspects are discussed.     

Comparative investigation of monoclonal and polyclonal antibodies directed against strain-specific and common antigenic sites on influenza H1N1 virus hemagglutinin

Antibodies directed against strain-specific and common antigenic sites of H1N1 influenza virus hemagglutinin were tested comparatively, using monoclonal antibodies raised against strain A/Brazil/11/78 and polyclonal antibodies directed against strains A/Brazil/11/78, A/USSR/97/77, A/PR/301/54, and A/FM/1/47. The patterns of competition between antibodies for adsorption onto homologous virus indicated that the monoclonals comprised antibodies directed to each of the two strain-specific (Sa and Sb) and common antigenic sites (Ca and Cb) of virus hemagglutinin. Polyclonal strain-specific antibodies (SSA) yielded the competition patterns of mixtures of anti-Sa and anti-Sb antibodies and polyclonal common antigen antibodies (CAA) yielded those of mixtures of antibodies directed against sites Ca and Cb, indicating that the polyclonal preparations comprised a similar repertoire of antibodies, as represented by the panel of monoclonals. This conclusion was confirmed by determining, by means of equilibrium filtration, the number of epitopes per homologous virion(s) recognized by antibody preparations and their mixtures. Polyclonal SSA and CAA gave s values not significantly different from those of mixtures of the corresponding monoclonal antibodies. The strains tested were found to possess equivalent numbers of strain-specific and common epitopes per virion. The competition between antibodies was further examined in terms of the additiveness of s values they recognize in simultaneous reactions. No competition was observed for the monoclonal antibody pairs anti-Sa/anti-Ca, anti-Sa/anti-Cb and anti-Sb/anti-Cb, indicating that these antibodies combined with nonoverlapping epitopes. Polyclonal SSA and CAA yielded partial competition. The equilibrium constants (K) of comparable SSA and CAA were within the same range, and SSA and CAA did not influence their binding avidity when allowed to react simultaneously with homologous virus.     

Collection tubes with or without gel separator did not interfere with detection of rubella virus antibodies IgM and IgG

Rubella infection is an exanthematic disease, with high prevalence in the adult population. The only modality of disease that causes serious consequences is congenital rubella syndrome (CRS), which happens when a pregnant woman seronegative to rubella virus acquires the infection during early pregnancy. Due to the lack of signals and characteristic symptoms of disease, diagnosis of rubella is based essentially on laboratory tests: antibodies detection and/or virus isolation. Results of serologic tests should always be interpreted with caution, because they can be affected by the quality of blood samples, processing and storage of sera, the equipment and reagents used to perform tests, and finally by the technical expertise and training of biologists. The collection tubes with gel seem to facilitate serum separation, but on the other hand gels can retain and consequently decrease antibody titers. Therefore, we decided to investigate whether the use of collection tubes containing gel separator might interfere with rubella virus antibody detection in blood samples from children. We did not observe statistically significant differences with respect to rubella virus antibody detection (immunoglobulin M [IgM] and immunoglobulin G [IgG]) for samples collected in tubes with or without gel separator, from the two evaluated manufacturers.     

ANTIGENIC ANALYSIS OF CERTAIN GROUP B ARTHROPOD-BORNE VIRUSES BY ANTIBODY ABSORPTION

A method for carrying out antibody absorption studies for antigenic analysis of group B arthropod-borne (arbor) viruses is described and examples of homologous and heterologous absorption curves are presented. Evidence that antigenic structure can be a stable property was obtained with three strains of West Nile virus isolated from different hosts in different countries over a period of years. Comparative studies with viruses of the Japanese B-St. Louis-West Nile subgroup indicate that each virus contains a completely specific antigen as well as one or more cross-reactive components. Strains of yellow fever virus isolated in America were shown to lack an antigen present in strains of African origin although no differences were found between isolates from the same geographical area. The attenuated 17 D vaccine strain of yellow fever was found to have acquired an additional antigen not present in the unadapted parent or in other strains tested. However, alteration in pathogenicity for man was not found to be necessarily attended by any antigenic modification, as shown by the antigenic identity of the French neurotropic vaccine strain with its pantropic parent.     

Immunochemical studies of foot-and-mouth disease. V. Antigenic variants of virus demonstrated by immunodiffusion analyses with 19S but not 7S antibodies

Three antigenic variants of foot-and-mouth disease virus, type A, strain 119, were demonstrated in Ouchterlony analyses utilizing serum collected from guinea pigs 7 days postinfection (DPI). Such antisera contain antibodies of the 19S class. Guinea pig antisera that contained antibodies of the 7S class were unable to distinguish between the antigenic variants. Similarly, 19S antibody was able to demonstrate antigenic differences in trypsin- and chymotrypsin-treated viruses that were not detected by 7S antibody-containing antisera. One of the antigenic variants of virus is apparently the wild type and is tentatively considered to have two antigenic determinant groupings termed the a- and b-sites (140S-ab). The 140S-ab variant was the sole or predominant antigenic type produced in guinea pigs and in large plaque-forming- and tissue culture-low passage sources of the virus. Another antigenic variant appears to possess only the b-site (140S-b) and was the major constituent in tissue culture-high passage virus preparations. The third variant, a small plaque former, was also devoid of the a-site and contains an antigenic determinant that is related to, but not identical with, the b-site. This variant appears to be a minor constituent of tissue culture-high passage virus. 7-DPI serum could be absorbed with a suitable concentration of tissue culture-high passage virus to remove antibody reactive with the b-determinant site. This absorbed serum still precipitated 140S-ab virus by virtue of still containing antibody reactive with the a-determinant site; however, the neutralizing activity was eliminated. This suggests that the b-site is critical with respect to neutralization while the a-site is noncritical.     

浙江省瑞安地区育龄妇女孕前6种感染性病原体血清学调查分析

目的 了解浙江省瑞安地区育龄妇女孕前6种感染性病原体的感染情况,为本区域妇女保健和优生优育工作提供实验依据。 方法 采用酶联免疫吸附试验(ELISA)对4153名育龄妇女联合检测乙型病毒性肝炎(乙肝)表面抗原(HBsAg)、梅毒螺旋体抗体(抗-TP)、人类免疫缺陷病毒抗体(抗-HIV1/2)及弓形虫(TOX)、风疹病毒(RV)、巨细胞病毒(CMV)相关的IgM/IgG抗体。 结果 4153名育龄妇女中,HBsAg阳性296例(7.13%);抗-TP阳性18例(0.43%);抗-HIV1/2阳性1例(0.02%);TOX、RV、CMV 3种病原体IgM抗体阳性率分别为0.29%、0.14%和0.84%,IgG抗体阳性率分别为1.13%、60.15%和89.86%。 结论 瑞安地区育龄妇女存在上述6种感染性病原体的感染,孕前检测和及时预防、有效干预有利于优生优育。     

STUDIES OF ANTIGENIC DIFFERENCES AMONG STRAINS OF INFLUENZA A BY MEANS OF RED CELL AGGLUTINATION

A study of cross inhibition tests among strains of influenza A virus and their antisera showed that the results obtained were subject to a certain amount of variation due to the red cells, the virus suspensions, and the ferret antisera employed. Methods have been demonstrated for handling the data obtained from such tests, so that these variables were corrected or avoided, making it possible to use the agglutination technique for antigenic comparisons. The antigenic pattern of eighteen strains of influenza A virus, obtained from the 1940–41 epidemic in the United States, has been compared by means of agglutination inhibition tests with ferret antisera. No significant antigenic differences were found among sixteen of these strains (all isolated from throat washings by the inoculation of chick embryos) although they were obtained from individuals in widely separated regions of the country. Two strains, from cases occurring early in the epidemic and isolated from throat washings by ferret and mouse passage, showed a slight but significant strain difference from the other strains and from each other. One of the 1940–41 strains on cross test resembled the PR8 strain more closely than any other stock strain tested.     

Antigenic drift in influenza A viruses. I. Selection and characterization of antigenic variants of A/PR/8/34 [HON1] influenza virus with monoclonal antibodies

Antigenic variants of A/PR/8/34 [HON1] influenza virus were selected after a single passage of the parent virus in embryonated chicken eggs in the presence of monoclonal antibodies to this virus. The monoclonal antibodies were produced by a hybridoma and were specific for an antigenic determinant on the HA molecule of the parent virus. Seven antigenic variants were analyzed with 95 monoclonal anti-HA antibodies prepared in vitro in the splenic fragment culture system. Three subgroups of antigenic variants were distinguished. The antigenic changes were primarily recognized by monoclonal antibodies to the strain- specific determinants of the parental hemagglutinin (HA) molecule. Monoclonal antibodies to HA determinants shared (in an identical or cross-reactive form) by parental virus and more than three heterologous viruses of the HON1 and H1N1 subtypes were unable to recognize the antigenic change on the variants. Similarly, heterogeneous antibody preparations could not differentiate between parental and variant viruses. The results are compatible with the idea that the HA of PR8 has available a large repertoire of antigenic modifications that may result from single amino acid substitutions, and that antigenic changes can occur in the strain- specific determinants on the HA molecule in the absence of concomitant changes in the cross-reactive HA determinants. The findings suggest that antigenic drift, in order to be epidemiologically significant, probably requires a series of amino acid substitutions in, or close to, the antigenic area on the HA molecule.     

Antigenic and genomic differences of two Jasper strains of infectious pancreatic necrosis virus.

Strains of infectious pancreatic necrosis virus (IPNV-Jasper) obtained from two different laboratories were compared serologically with polyclonal and monoclonal antibodies. Nucleotide sequence and restriction endonuclease patterns of 359-bp fragment of genome segment A cDNA were also compared. Substantial differences were found in both analyses that will support the fact that the two Jasper strains are not identical.     

The analysis of the monoclonal immune response to influenza virus. II. The antigenicity of the viral hemagglutinin

The antigenicity of the hemagglutinins (HA) of five influenza viruses of the A0 and A1 subtypes has been analyzed by means of monoclonal antibodies of murine origin produced in vitro. Secondary monoclonal anti-HA(PR8) antibodies were able to differentiate 14 antigenic determinants (or groups of determinants) on the HA of five influenza virus strains of the A0 and A1 subtypes. Taking into account that certain pairs of determinants delineated on heterologous HA may reflect the heterogeneity of the humoral immune response to a single homologous determinant, the presence of at least eight determinants (host cell-derived determinants not included) on the homologous HA of PR8 and probably on the HA of influenza viruses in general is postulated. Three types of HA-determinants of A0 and A1 influenza virus strains could be distinguished: strain-specific, partially shared, and determinant(s) common to all five virus strains tested. Roughly 40, 55, and 5%, respectively, of the secondary anti-PR8 antibodies of BALB/c mice were directed against determinants belonging to either of the three types.     

The development of immune-enzyme test-systems to diagnose rubella

Two new immune-enzyme test-systems are developed to diagnose rubella using the natural antigen of rubella virus. The test-systems by their characteristics are equal with the known international models and can be recommended for large implementation in clinical diagnostic laboratories of health institutions to detect antibodies classes G, M to rubella virus both for disease diagnosis and mass serologic examination of immune status of population and evaluation of effectiveness of vaccination.     

IMMUNOLOGICAL STUDIES WITH THE VIRUS OF INFLUENZA

Following infection with the virus of influenza, both ferrets and mice develop a state of active immunity to reinfection. The serum of these animals contains neutralizing antibodies, as evidenced by the capacity of the serum to confer passive protection to mice against infection with the P.R.8 and Phila. strains of the virus of human influenza. Rabbits which are apparently insusceptible to infection with the virus of influenza produce specific antibodies in response to repeated injection of virus-containing material. The serum of immunized rabbits affords passive protection to mice against mouse-virulent virus. Although the subcutaneous or intraperitoneal injection of the living virus does not produce infection in mice, animals so treated acquire active immunity against subsequent infection by the intranasal route. Neutralization tests with the serum of patients before and after recovery from influenza, pneumonia and the common cold indicate that neutralizing antibodies arise as a specific response to infection with the virus of influenza. The immunological identity of strains of influenza virus recovered from human sources has been established, and the possible existence of strains of related, but not identical, antigenic structure is discussed.