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PubMed1983

Monoclonal antibodies to the HN glycoprotein of Newcastle disease virus. Biological characterization and use for strain comparisons.

We have isolated nine hybridomas secreting monoclonal antibodies directed against the HN glycoprotein of D26 strain of Newcastle disease virus (NDV) and classified them into three groups by their biological reactivities. The group I antibodies from six clones had high hemagglutination inhibition (HI) and neutralization titers, and exhibited neuraminidase inhibition (NI) activity with substrates, both bovine fetuin and N-acetyl neuraminlactose, although the levels of maximum inhibition were greater with the former substrate. The group II antibodies from two clones also had high HI activity but showed a strongly substrate-dependent NI, with efficient inhibition against fetuin and a total lack of inhibition against neuraminlactose. These antibodies had neutralization capacity but the titers were much lower than those of group I antibodies. One clone (group III) secreted antibody which exhibited HI and NI with either substrate but no detectable neutralization activity. Frequency of isolation of antigenic variants and competitive binding assays have shown that group I and group II antibodies may recognize distinct regions not overlapping each other whereas antibodies placed within each of the two groups are to the respective same overlapping regions. The site of group III seemed to be close to or overlap the group I determinant but distinct from group II region. Using the isolated monoclonal antibodies we compared seven heterologous strains by HI and neutralization tests as well as by enzyme-linked immunosorbent assay. The results indicated that the regions recognized by group I antibodies would be conserved among the strains whereas those by the other two antibody groups might undergo considerable changes.

Antibodies, Monoclonal↗
PubMed1976

Plaque assay of Sendai virus in monolayers of a clonal line of porcine kidney cells.

The MN strain of Sendai virus formed distinct plaques in monolayers of PS-Y15 cells, an established porcine kidney cell line. The plaque-forming ability was neutralized by specific antibody to the virus. A linear relationship was found between the concentration of virus and the number of plaques. The sensitivity of this assay was about equal to that of the in ovo titration. When applied to the serum neutralization test, the end points obtained were comparable to those of the hemagglutination-inhibition and complement-fixation tests.

Animals↗
PubMed1970

Isolation of a bunyamwera group arbovirus from a naturally infected caribou.

A Bunyamwera group arbovirus was isolated from the blood and from the brain of a female caribou parasitized with meningeal worms. The virus passed through a 0.45 micron filter; was ether sensitive; possessed no hemagglutination properties; could be propagated in suckling mice, 6-day old chick embryos, and BHK-21 tissue culture; and produced plaques in chick embryo fibroblast tissue culture. Neither complement-fixation or neutralization tests were sensitive enough to determine the serotype of the virus.

Animals↗
PubMed1991

Follow-up of protective antibody level after post-exposure vaccination with purified tissue culture rabies vaccine (PCEC) small doses intradermally.

Twenty-nine vaccinees, 18 males, 11 females, aged 2-61 years (median 12 years) received PCEC intradermally for post-exposure prophylaxis during February to May 1989. Twenty-one cases received 4 sites of 0.1 ml ID on days 0, 3, 7 and 1 site ID on days 28 and 90. Four cases received 4 sites ID on days 0, 3, 7 and 1 site on days 14 and 28. The other 4 cases got the different schedules of ID by the poor compliance. Blood specimens were taken from these vaccinees at 2, 6 or 7, 9, 12 and 16 months after the initial dose. Neutralizing antibodies were measured by standard mouse neutralization test used WHO rabies antiserum as reference. All 65 tested sera showed positive neutralizing antibody. The GMT of antibodies at months 2, 6 or 7, 9, 12 and 16 were 17.68, 2.01, 1.56, 0.88 and 0.56 IU/ml respectively. Mild itching at injection sites was reported in 3 cases and low fever with malaise in 1 case.

Adolescent↗
PubMed1990

Characterization of an intermediate adenovirus strain.

An intermediate strain of human adenovirus of subgenus D was investigated by type specific serological reactions and restriction endonuclease analysis. The latter method showed the strain identical to the prototype strain of human adenovirus type 9 as well as did serum neutralization tests. In contrast with the previous methods haemagglutination inhibition tests showed the strain related to both the prototypes strains of human adenovirus 9 and 13.

Adenoviruses, Human↗
PubMed1986

Flaviviruses in South Africa: diagnostic procedures.

Employing rabbit immune serum, 10 flaviviruses known to be present in South Africa could be divided into 5 serological subgroups. The subgroups conform to the general pattern described for the group. Sera from experimentally infected calves and lambs were monospecific in neutralization tests, but cross-reacted in haemagglutination inhibition tests. These results suggest that sheep and cattle sera from the field can best be tested by microneutralization tests. The greater sensitivity of embryonated hen's eggs for some viruses and of one-day-old mice for other viruses necessitates the employment of both systems for the isolation of flaviviruses from field specimens.

Animals↗
PubMed1983

[Comparative evaluation of the methods of determining perfringens A antitoxin].

The methods for determining the level of type A Perfringens antitoxin in human blood sera were examined and compared. The ratios for correlating the data obtained in the toxin neutralization test (NT) in vivo, in the passive hemagglutination test (PHT), and as a result of the enzyme-labeled immunosorbent assay (ELISA) with regard to the antitoxin level measured in the NT in vitro were equal to 0.88, 0.64 and 0.39, respectively. The sensitivity of the NT in vivo and in vitro was 0.25 IU/ml, that of the PHT 0.01-0.005 IU/ml, and that of the ELISA 0.01-0.02 IU/ml Perfringens antitoxin. To perform the NT, not less than 1 ml blood serum is required, while for the PHT and ELISA, 0.1-0.05 ml. Provided hyghly purified anatoxin is used for preparing the erythrocyte diagnosticum Perfringens, and polysterene plates are sensitized in performing the ELISA, all the reactions are specific. While titrating human blood sera containing type A Perfringens antitoxin, use in the PHT may be made of type A Perfringens rabbit antiserum as reference.

Antitoxins↗
PubMed1977

[Study of the antigenic properties of herpesvirus strains isolated from herpetic lesions at different sites].

The antigenic properties of 15 strains of hepesvirus isolated from herpetic lesions of different localization were studied. The serotype of each strain was established by the neutralization tests with hyperimmune sera to the reference type 1 and 2 strains: the cross-neutralization tests revealed antigenic relationships between the strains of 1 and 2 serotypes. Most strains isolated from lesions of the genitalia belonged to type 2, although one strain isolated in herpes genitalis belonged to type 1, and 2 strains isolated from facial lesions also belonged to type 2. These results confirm the necessity of using inactivated polyvaccine prepared from herpesvirus strains of antigenic types 1 and 2 for relapse control therapy instead of using monovalent type 1 and type 2 vaccines as reported by foreign authors.

Antigens, Viral↗
PubMed1977

Development and evaluation of an enzyme-labeled antibody test for the rapid detection of hog cholera antibodies.

A rapid enzyme-labeled antibody (ELA) microtechnique for the screening of swine for hog cholera antibodies was developed and evaluated with a blind study, using a 640-sample hog cholera serum bank. The total time to run a group of 22 samples was approximately 1 hour. The ELA test results correlated greater than 99% with hog cholera serum-neutralization test results on the same serums. Test results also indicated that the ELA test shares with the hog cholera serum-neutralization test the problem of cross reactions between the antibodies of hog cholera and bovine viral diarrhea.

Animals↗
PubMed1971

Classification of North American porcine enteroviruses: a comparison with European and Japanese strains.

Seventy-two strains of porcine enteroviruses including strains from North America, England, and Japan were compared by cell culture neutralization tests to provide a serological classification of North American strains. From the tests, eight serogroups evolved, with serogroup 8 having a possible three subgroups. There appeared to be some intergroup relationship among certain viruses in groups having the same specific cytopathic effect (CPE) in cell culture. There was no apparent cross-reaction between the group with type II CPE and groups with type I CPE. Antisera produced in nonhost chickens provided a satisfactory antibody source for the tests. It was proposed that satisfactory typing of viruses could be done best by cross-neutralization rather than by one-way neutralization tests. This provided the homologous serum titer as determined in the laboratory conducting the tests which was important where comparisons are made on the basis of per cent of the homologous titer. It was further emphasized that viruses of tissue origin and their antisera have fewer intergroup reactions than viruses of intestinal origin and their antisera. General type strains and specific North American strains were suggested as satisfactory type sera and viruses for seven of the eight groups to facilitate virus identification.

Animals↗
PubMed1984

A serological survey for Bhanja virus in Czechoslovakia.

Sera of 259 persons, 801 sheep, 54 goats and 60 cows from several regions of Czechoslovakia were examined by tube-neutralization test (TNT) and haemagglutination-inhibition test (HIT) for antibodies against Bhanja virus. The results of both assays correlated well, but TNT was a more sensitive test than HIT. Antibodies neutralizing Bhanja virus were detected in 2.7% of persons, 5.1% of sheep, 18.5% of goats and 16.7% of cattle, most frequently in the district Roznava (Eastern Slovakia), where 38.5% of goats, 26.7% of sheep, 16.7% of cattle and 9.5% humans (predominantly goat or sheep breeders) were positive. A recent circulation of the virus in natural foci of that area is revealed by the detection of antibodies in several calves and lambs, which grazed in one year (1982) only. Roznava district is also unique (among the areas examined) in the presence of the tick Haemaphysalis punctata, principal vector of Bhanja virus in Europe.

Animals↗
PubMed1989

Isolation of peplomer glycoprotein E2 of transmissible gastroenteritis virus and application in enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) based on peplomer glycoprotein E2 was developed for the detection of antibodies to transmissible gastroenteritis virus (TGEV). Purified preparations of E2 were isolated by solubilization of the viral membrane with nonion detergent Nonidet P-40, followed by sucrose density gradient sedimentation. ELISA optical density values with E2 antigen significantly exceeded the indices when other TGEV protein or intact virion antigen was used. It was shown that a virus protein concentration in the E2 preparation of 500 ng per well is sufficient to sensitize the solid phase of microplates. A comparison of the ELISA and the virus neutralization test for the detection of TGEV antibodies was conducted. A significant correlation between the ELISA and the virus neutralization test was shown (r = 0.97). This serological test may be successfully used for various immunologic investigations.

Animals↗
PubMed1985

Endemic Lassa fever in Liberia. III. Characterization of Lassa virus isolates.

Sixty-three virus isolates were obtained by inoculation of Vero cells with sera from 50 hospital in-patients in Liberia with acute febrile illnesses. 57 of the isolates were presumptively identified as Lassa virus (LV) by direct fluorescent antibody (DFA) staining of inoculated Vero cells. These, and six additional isolates obtained only by titration of supernatant fluids from inoculated Vero cells, were definitively identified as LV in a neutralization test. Two additional LV isolates were obtained from a patient's sera from Nigeria. By cross-neutralization tests, the Nigerian LV strains were serologically identical to the prototype Nigerian LV strain (PP) but were distinct from both a reference LV strain from Sierra Leone (SL), and from the Liberian (LIB) strains isolated in this study. The LIB and SL strains were closely related to each other, but not to the Nigerian LV strains. LIB LV strains were tested for virulence in strain 2 and 13 guinea-pigs, and a spectrum of virulence was observed which correlated only approximately with disease severity for human patients. Two human-lethal isolates killed all inoculated strain 2 and 13 guinea-pigs, whereas nine isolates from mildly ill patients were benign for guinea-pigs. Yet some LV isolates from severely ill or lethally infected patients, especially those from pregnant women and infants, were totally benign for guinea-pigs. These data suggest that antigenically distinct LV strains exist in nature, and that antigenically indistinguishable LV isolates may differ in virulence potential for various hosts.

Animals↗
PubMed1986

Single-radial-haemolysis test for diagnosing flavivirus infections, particularly Japanese encephalitis.

Use of the single-radial-haemolysis (SRH) technique for the diagnosis of flavivirus infections is described. A large number of paired and single convalescent serum samples collected from cases of encephalitis during two major outbreaks in Kolar district of Karnataka State in India during 1977 and 1979 were tested by this technique. The results were compared with those obtained in the haemagglutination inhibition (HI) test in all cases, and the complement fixation (CF) and neutralization tests in some cases. Japanese encephalitis virus was shown by the SRH test to be the major etiologic agent responsible for both epidemics. This was corroborated by the HI, CF and neutralization test results. The single-radial-haemolysis test was found to be simpler and more specific and sensitive than the haemagglutination inhibition test.

Encephalitis, Japanese↗
PubMedDate not supplied

Antidiphtheria and antitetanus immunity of recruits in Romania.

The concern for maintaining a high antidiphtheria and antitetanus immunity level is permanent. The paper approaches the study of antidiphtheria and antitetanus immunity levels in a group of young recruits (who had been administered a DT booster 5-7 yrs before). The titres of antibodies were determined concomitantly by the neutralization test (NT) in vivo and by the passive hemagglutination assay (PHA) in vitro. The results obtained by the neutralization tests revealed (by the estimations shown by the geometrical means) a high antidiphtheria and antitetanus immunity level proved by an exceeding of the protection limits (0.03 IU/ml and 0.01 IU/ml) of 89 x and 953 x, respectively. The analysis of individual titres obtained by NT showed that of 540 subjects in whom diphtheria antitoxin was determined, 93.52% had protective titres, while of 619 subjects in whom the tetanus antitoxin was evaluated, 97.26% were immune. The results obtained by PHA were comparable with those obtained using the reference methods.

Adult↗
PubMed1998

[Study of coxsackievirus group A. I. Serological variation of coxsackieviruses group A isolated in Gifu Prefecture].

Forty four isolated strains of Coxsackievirus group A were tested for antigenic variation with antiserum against each prototype strain by neutralization test. Isolates of type 2, type 4, type 5, type 8 and type 10 of Coxsackievirus group A, were not confirmed antigenic variation by neutralization test with immune sera to the prototype virus strain. However, 57.1% of type 9 isolates of Coxsackievirus A group were confirmed as variants. In isolates of Coxsackievirus group A type 16, the isolate in 1982 was neutralized with antiserum against the prototype strain, but the isolates after 1984 were neutralized to low titer or not at all by immune sera to the prototype virus strain. Therefore, the isolated strains were tested with immune sera against the isolated strain in 1988. So that, the isolated strains in 1982 and after 1984, were neutralized with the serum against the isolate in 1988, and moreover, the neutralizing titer of prototype strain was a third of the isolate. So that, for identification of type 16 of Coxsackievirus group A, it is necessary to use the immune sera against recently isolated strains.

Antigenic Variation↗
PubMed1969

Western encephalomyelitis virus infection in "indicator" chickens in southern Alberta.

Sera from indicator chicken flocks situated in southern Alberta near Lethbridge were tested by the hemagglutination-inhibition (HI) technique for antibodies to Western, Eastern and St. Louis Encephalitis viruses during the summer and early fall of the four years 1964 to 1967.One chicken in 1964, 90 in 1965 and five each in 1966 and 1967 were positive to Western encephalomyelitis (WE) virus by hemagglutination-inhibition tests. All of the positive sera were confirmed by neutralization test (NT) in infant mice. No antibodies to the Eastern and St. Louis viruses were detected. Infection with WE virus was detected in each of the four years, indicating that WE virus is endemic to southern Alberta with a marked seasonal incidence occurring between the second week in August and the third week in September. An improved technique for filtering sera is described.

Animals↗
PubMed1993

ARACHnase. An evaluation of a positive control for platelet neutralization procedure testing with seven commercial activated partial thromboplastin time reagents.

ARACHnase (Hemostasis Diagnostics International Co., Denver, CO) is a normal plasma that contains a venom extract from the brown recluse spider, Loxosceles reclusa, which mimics the presence of a lupus anticoagulant (LA). Seven activated partial thromboplastin time (APTT) reagents were used for platelet neutralization procedure (PNP) testing with ARACHnase: Automated APTT (Organon-Teknika, Durham, NC); Thrombofax and Thrombosil (Ortho, Raritan, NJ); Actin and Actin FSL (Dade, Aguado, PR); and Thromboscreen-Kontact and Thromboscreen-APTT LS (Pacific-Hemostasis, Ventura, CA). ARACHnase consistently displayed a positive PNP result of greater than 5 seconds correction of the initial baseline APTT. Thus, ARACHnase may provide a positive control for LA testing, regardless of the choice of APTT reagent and activator/phospholipid combination.

Adult↗