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PubMed1982

Rapid identification and serotyping of poliovirus isolates by an immunoassay.

An enzyme-linked immunosorbent assay (ELISA) for the identification and typing of polioviruses is described. Polioviruses could be rapidly detected and typed from cell culture supernatants by a double antibody sandwich technique. The assay is valuable for the rapid screening of a large number of viral isolates from water samples submitted for virological analysis. Several hundred isolates per day can be typed and only the remainder have to be tested by the conventional serum neutralization test.

Antibodies, Viral↗
PubMed1967

Friend Leukemogenic Virus-neutralizing Antibody from Mouse Ascitic Fluid.

Ascitic fluid antibody produced in C57/B1 mice immunized with Friend leukemogenic virus exhibited potent neutralizing activity. In vitro neutralization tests revealed that a mean neutralization index of 3.0 was achieved, and it was shown by sucrose gradient ultracentrifugation that this antibody resembled the 7S type. A mean yield of 6.7 ml of fluid per mouse per weekly paracentesis was obtained over an 8-week period. The ascitic fluid antibody to Friend virus was also active in vivo. Mice given antibody 3, 5, 7, and 9 days after infection with Friend virus did not develop the splenomegaly characteristic of Friend disease.

Journal Article↗
PubMed1999

Seroepidemiology of California and Bunyamwera serogroup (Bunyaviridae) virus infections in native populations of Alaska.

This study investigated the geographic distribution and prevalence of antibodies to California and Bunyamwera serogroup viruses in Native populations of Alaska, and demographic and ecologic risk factors associated with exposure. Sera (n = 1,635) from 18 communities were screened using an ELISA. All age groups were tested for antibodies to Jamestown Canyon (JC), Inkoo (INK), snowshoe hare (SSH), and Northway (NOR) viruses; persons > or = 45 years old (n = 90) from six communities were additionally tested for antibodies to Tahyna (TAH), Batai (BAT), Cache Valley (CV), and Sindbis (SIN) viruses. Thirty free-ranging mammals were tested by a plaque reduction neutralization test (PRNT) for antibodies to all eight viruses and to Getah (GET) virus. In Natives, overall antibody prevalence was 24.9% (JC = 17.6%, monotypic JC = 6.5%, INK = 11.1%, monotypic INK = 0.6%, SSH = 6.8%, monotypic SSH = 3.5%, and NOR = 6.2%). Five TAH, CV, and BAT virus exposures may be serologic cross-reactions, and no SIN virus antibodies were detected. Sindbis-like virus antibodies were found in 30% of the mammals. Most mammals had antibodies to NOR (83.3%) and California serogroup (70.0%) viruses; no GET virus exposures were found. Significant risk factors for human bunyavirus exposures were age group, ethnic-linguistic group, biotic province, climate zone, terrestrial vegetation, and presence of some ungulates and small mammals in communities. Sex was not a significant risk factor.

Adolescent↗
PubMed2002

[Diphtheria--results of an immunologic survey].

The objective of the immunological survey (IS) was in addition to assessment of the overall immunity of the Slovak population against diphtheria to test the effectiveness of vaccination and suitability of the used vaccination pattern and to assess the persistence of antibodies against diphtheria in more advanced age, and possibly the need of revaccination. The sera were tested by means of the neutralization test on cell cultures. The level of diphtheria antitoxin was assessed quantitatively. In the reaction standards were used--diphtheria toxin 79/1 1000 Lf, produced in the National Institute of Public Health and the Environment Bilthoven, Netherlands and the diphtheria antitoxin Diphtheria antitoxin equine British Standard 66/153, obtained from WHO International Laboratory for Biological Standards, Great Britain. The overall immunity assessed on a nationwide scale in Slovakia was adequate (88.2%). In the child population the level of antibodies correlated well with the administration of individual vaccinations against diphtheria. In 6- to 10-year old children the serum positivity was as high as 100%, in older children it did not drop below 95%. A more marked decline of serum positivity was found in the population above 40 years. The highest proportion of sensitive subjects was in the group of 50-59-year-old ones (45.2%). The antidiphtheritic immunity of the population under 50 years is very good. Inadequate immunity of adults above 50 years revealed the need of administering a booster dose against diphtheria which will have a positive impact on the antibody level of this age group of the population.

Adolescent↗
PubMed2003

[Serum antibody response and Hantavirus RNA sequencing in patients with hemorrhagic fever renal syndrome in Yantai areas].

OBJECTIVE: To understand antibody responses to and RNA sequences of Hantavirus in patients with hemorrhagic fever renal syndrome (HFRS) in Yantai areas and to demonstrate the type of the prevalent viruses caused HFRS. METHODS: Serum specimens collected at acute and convalescent stages from 90 patients with HFRS and IgM and IgG antibodies against Hantavirus were detected with ELISA, and cross plaque reduction neutralizing tests were performed to detect neutralizing antibody. Viral RNA was extracted from the patients? sera by using Trizol method and nested PCR was utilized to amplify the specific segments of the viral cDNA and the products of the PCR were TA cloned and then the nucleotide sequences were determined. RESULTS: The IgM antibody was positive in 82.2% (88/107) of the patients while the IgG antibody was positive in 85.7% (66/77) of the patients. Both the serologic and sequence analyses demonstrated that the epidemic of HFRS in Yantai areas was caused by mixed types of Hantavirus. The prevalent strains of Hantavirus had higher homology with the strains isolated in Korea than with those isolated previously in China. CONCLUSIONS: The serologic and sequencing analyses indicated that the epidemic of HFRS in Yantai areas was caused by mixed types of Hantavirus dominated by type SEO.

Antibodies, Viral↗
PubMed1992

No serological evidence for the presence of swine vesicular disease virus in South Africa.

An indirect ELISA incorporating a protein A-peroxidase conjugate was developed for detecting antibodies to swine vesicular disease virus (SVDV) in pig sera. This test and a conventional virus neutralization test were found to be equally sensitive. A total of 2846 pig sera collected from various abattoirs in South Africa were tested using the indirect ELISA. No serological evidence of infection with SVDV in pigs in South Africa was found.

Animals↗
PubMed1976

[Contamination of fish by agents of botulism type F and differentiating it from type E].

A total of 1859 samples of fish and various sea animals were examined for contamination with causative agent of botulism. The cultural fluid of 4--5-day cultures of the samples was tested in the reaction of neutralization with the diagnostic antitoxic antibotulin sera. types A, B, C, E. The causative agents of botulism (types A--7,B--16, C--5, E--128) were revealed in 156 samples. The sera were diluted to the concentration of 1 IU/ml for differentiation of the toxins types B and F in the neutralization test. Of 128 samples which gave a positive reaction with the serum of type E, 75 were identified as type F. In connection with the aforesaid the authors recommended in all the cases of botulism of type E in man to carry out differential diagnosis between the causative agents of botulism of types E and F and, on the basis of these data, to solve the problem on the necessity of production of therapeutic antibotulin serum of type F.

Animals↗
PubMedDate not supplied

[Determination of immune antitetanus antibodies using hemagglutination tests].

The active immunization by the in vitro method was analyzed with the aim to assess whether it can be recommended for the judgement of the immune status of the individuals. The technique developed by Boyden was used: the examinee's blood serum was mixed with sheep (or human) erythrocytes which were carriers of tetanus toxoids, agglutination developed and the reaction was read after 2 and then after 4 hours. The agglutination titre was expressed in IU/ml calculated by means of parallely titred working serum (human tetanus immunoglobulin). Three hundred and sixty-five serum samples from 258 immunized persons (183 males and 75 females) and 20 nonimmunized controls with the range of ages between 10 and 65 years were examined. Fifty-one serum samples were simultaneously tested by the in vivo neutralization test (mice), the so-called "L+" method. The examinees immunized by the classic method had antitoxin level above 0.01 IU/ml for at least 5 years and more. The group of examined persons with the incomplete classic immunization (2 injections) showed a very similar antitoxin level in 91.2% of the cases. Equal results were obtained for a group of examinees with simultaneous immunization (antitoxic serum+tetanus adsorbate and 2 adsorbate injections in succession). The examinees who had a history of only one tetanus adsorbate injection had antitoxin levels above 0.01 IU/ml in 18.75% of the cases. The examinees with the so-called accelerated immunization showed antitoxin concentration above 0.01 IU/ml in a greater percentage (28.6%), but the level decreased very quickly and it was below 0.01 IU/ml already after one year.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Equine viral arteritis. Current status in Finland.

A serological study for antibodies against equine arteritis virus (EAV) in Finland was performed during 1996. All equine sera delivered to the Virology Unit at the National Veterinary and Food Research Institute were tested with a micro-neutralization test, using the Arvac strain as antigen. The study also included imported horses to evaluate EAV circulation in the countries of origin. Nucleocapsid gene sequences of 2 Finnish equine semen isolates were amplified with RT-PCR and sequenced. The genetic relationships of those isolates with strains isolated elsewhere in the world were analyzed. The Finnish isolates shared 98.2% nucleotide identity, and the closest relatives to the Finnish strains were isolated from the semen of 2 Norwegian horses in 1988 and 1989.

Animals↗
PubMed2002

Porcine reproductive and respiratory syndrome (PRRS) with special reference to clinical aspects and diagnosis. A review.

After a short introduction on Porcine Reproductive and Respiratory Syndrome (PRRS) regarding the history, the first occurrence in several countries, and the causal virus, designated Lelystad virus, a description is given of the clinical aspects and several diagnostic methods. After some general remarks on the clinical aspects, the epidemic and the endemic phase of the disease are described. Regarding the diagnosis, special attention is paid to the detection of antibodies and of the PRRS Virus (PRRSV). Regarding the detection of antibodies, a description is given of three tests: the immunoperoxidase monolayer assay, the enzyme-linked immunosorbent assay, and the serum neutralization test. Concerning the detection of PRRSV, attention is paid to the isolation of the virus, the demonstration of PRRSV antigens in frozen or fixed tissue using immunohistochemistry or immunofluorescence, the in situ hybridisation technique and the Polymerase Chain Reaction (PCR).

Animals↗
PubMed1983

The NK function elucidated with respect to effector cells, target cells and other immunological in vitro tests.

The microcytotoxicity assay and the leukocyte migration inhibition test were unable to reveal any specific reactivity in patients suffering from localized skin melanoma. The non-specific reactivity measured by the microcytotoxicity assay, the so-called NK activity was found to be associated to the cells bearing Fc receptors, irrespective of T and non-T identity. Further more the NK activity depends on the target cell used (established cell lines versus short-term cultures) and the lymphocyte/target cell ratio. The NK activity measured by microcytotoxicity assay and the leucocyte migration inhibition test were compared by simultaneous implementation of the two test systems. No correlation between significant leucocyte migration inhibition and NK activity was found. In a tumor neutralization test workout in a nude mouse model, it was found that patient lymphocytes decreased the number of tumor takes and increase the latency period. However, the specificity of these reactions were uncertain.

Antigens, Neoplasm↗
PubMed1978

[Evaluation of the immune state of poultry against Newcastle virus via various serological reactions].

Studied were 336 sera of vaccinated and challenged chickens, 76 egg extracts, and 36 birds following challenge for the presence of serum antibodies against the Newcastle disease virus, using the hemagglutination-inhibition reaction, the agar gel diffusion precipitation reaction, and the virus-neutralizing test. The values of the antihemagglutinins, precipitins, and virus-neutralizing antibodies were investigated in relation to the immunobiologic resistance of birds to a velogenic Newcastle disease virus. A correlation was found between the antihemagglutinins and the neutralizing antibodies in broilers, aged 30-60 days, treated with an aerosol vaccine La Sota, and in henlayers treated muscularly with the Komarov vaccine. The presence of antihemagglutinin titers of 1:40 and higher values or positive neutralizing indices in the investigated birds were able to provide immunobiologic protection in challenging with a velogenic virus. Precipitins were detected in the blood sera of the challenged birds, which made reasonable their use as a sign pointing to the passage of a velogenic virus through the birds. The lower number of cases with positive precipitin reactions in the vaccinated birds speaks against using objectively this index for the evaluation of the immunologic status.

Aerosols↗
PubMed1969

Microneutralization test for determination of rhinovirus and coxsackievirus A antibody in human diploid cells.

A method for determination of serum-neutralizing antibody titers to rhinovirus type 16 and coxsackievirus type A-4 in human diploid cells (WI-38) grown in Microtiter plates is described. A good correlation was observed when comparing neutralization tests in WI-38 and other cells. The WI-38 Microtiter method is relatively simple and economical. It is suitable for those laboratories which are required to conduct large-scale serological evaluation of antibodies for rhinoviruses and coxsackie A viruses. This system also can be used for cytomegalovirus and varicella-zoster virus, which grow relatively slowly.

Antibodies↗
PubMed1999

Intradermal testing for food and chemical sensitivities: a double-blind controlled study.

BACKGROUND: Confirming adverse reactions to foods and chemicals is fundamental in providing a basis for diagnosis and treatment of patients with reported environmental sensitivities. Provocation-neutralization testing is widely used in this respect but has not been thoroughly evaluated, therefore remaining a controversial and unproven technique. OBJECTIVE: This study investigated the validity of intradermal testing for evaluation of reported adverse reactions to a variety of incidents within the patient population at the Nova Scotia Environmental Health Centre. METHODS: A total of 132 people who were referred to the Nova Scotia Environmental Health Centre, a dedicated government-funded research and treatment facility for suspected environmental sensitivities, were tested by the technique of provocation-neutralization by the guidelines set out by the American Academy of Environmental Medicine. A panel of 13 foods, 9 chemicals, and 4 placebos (normal saline solution) was evaluated in a double-blind, randomized study. Symptoms and skin reactions were recorded, and response rates were determined for all substances, including saline solution injections. RESULTS: Seventy percent of the patients reported symptoms to 1 or more of the 4 saline solution injections. In comparison, 15% of patients experienced a skin reaction (wheal) to 1 or more injections of saline solution. Only 5% of individuals experienced a wheal to more than 1 saline solution injection, although 40% of the patients reported symptoms to more than 1 saline injection. Patients who experienced 1 or more reactions (wheal or symptoms) to saline solution were more reactive to injected allergens, on average reacting to 67% of active substances. Patients who experienced no reaction to the saline solution did experience a reaction to 48% of injected substances on average. Reaction by symptoms to foods, chemicals, and normal saline solution showed a random pattern, although wheal reactions showed a distinct pattern. Subsequent observations have indicated that experiencing no reaction to previous saline solution injections does not accurately predict response to saline solution in later testing. Some individuals who did not experience a reaction to saline solution in an initial screening later experienced a reaction to saline solution during further testing. CONCLUSIONS: Provocation of symptoms in usual testing conditions is not a useful tool for discriminating between reactions to saline solution and reactions to specific chemicals or foods. Skin response alone may be a more reliable indicator and will require cross-validation with other tests, such as oral and inhalation challenges and comparison with a control population. Heightened sensitivity and chaotic responses may be a feature of chemical sensitivity. Meanwhile, the results of provocation-neutralization testing, using symptoms alone as an indicator of neutralization, should not be used as a basis for clinical intervention.

Adolescent↗
PubMed1984

[Data from the serological examination of the population of the Republic of Congo for the presence of antibodies to orthopoxviruses. I. A comparative evaluation of different study methods and general results].

The selective survey of the population of the Republic of Congo for the presence of antibodies to orthopoxviruses has been carried out with the use of the neutralization test, the hemagglutination inhibition (HAI) test and the ELISA. Despite a prolonged period (15 years) elapsed since the transmission of natural smallpox stopped in this country and despite the almost complete cessation of immunization against this infection since 1977, antibodies to orthopoxviruses can be detected in a considerable proportion of the population: 29%. This percentage grows as older age groups are examined, reaching 90.6% in the age groups of 16 years and over. Antibodies to orthopoxviruses have also been detected in children under 5 years of age, born after the eradication of smallpox and having no vaccination scars. The possible causes of this phenomenon are discussed. The comparison of the results obtained with the use of different tests has confirmed high sensitivity of ELISA. The HAI test is less sensitive, but this is compensated by its simplicity and its easy use for screening procedures. Besides, the positive results of this test indicate that the corresponding sera contain sufficiently high titers of virus-neutralizing antibodies detected by means of ELISA, which is of importance for their subsequent interspecific differentiation.

Adolescent↗
PubMed2003

Haemagglutination-inhibiting antibody to influenza virus.

The results of the haemagglutination-inhibiting (HI) antibody test for influenza virus antibody in human sera closely match those produced by virus neutralization assays and are predictive of protection. On the basis of the data derived from 12 publications concerning healthy adults, we estimated the median HI titre protecting 50% of the vaccinees against the virus concerned at 28. This finding supports the current policy requiring vaccines to induce serum HI titres of > or = 40 to the vaccine viruses in the majority of the vaccinees. Unfortunately similar studies are scanty for the elderly, the group most at risk of influenza. There still remain many unsolved technical problems with the HI assay and we recommend that these problems be studied and the virus neutralization test as a predictor of resistance to influenza be assessed. Although the studies on this issue often give conflicting results, they generally show that HI antibody responses to influenza vaccination tend to diminish with increasing age, when health is often compromized. Advanced age in itself seems not to be an independent factor in this process. However, even in completely healthy elderly individuals the response to vaccination with an antigenically new virus may be strongly reduced compared with younger vaccinees.

Antibodies, Viral↗
PubMed1997

Emerging viral pathogens in long-term expatriates (II): Dengue virus.

Dengue virus infections have been well known for many years; still dengue virus is regarded as an 'emerging' pathogen, as the disease profile is changing. Its geographical range and overall incidence, and the incidence of the associated complications, dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), are on the increase. Modern-day travel and increasing urbanization seem to be the main contributing factors. In order to estimate the risk of infection during long-term stays in dengue-endemic countries, we tested sera obtained from 323 development aid workers and their family members who had spent on average 9.8 years in dengue-endemic regions for the presence of dengue virus antibodies. Dengue virus antibody screening was done by a commercially available immunofluorescence test (IF). Reactive samples were re-tested by an in-house IF and also tested for cross-reactivity to yellow fever virus using yellow fever IF and neutralization test (NT). Evaluation of the results revealed that the screening test has a specificity of at least 63.2%. In 12 of 19 initially positive cases crossreacting antibodies against yellow fever virus could be ruled out. Three cases remained indeterminable, whereas four of the reactive and 10 (out of 12) of the borderline reactive cases showed crossreactivity with yellow fever virus, probably due to previous vaccination. We found seroprevalence rates of 4.3% with no significant differences related to gender or area of upbringing. Seroprevalence rates were evaluated according to region of suspected or confirmed infection. In two cases the dengue infection had taken a classical clinical course; in another three cases an extraordinary febrile illness was reported in the history. None of the other seropositive individuals had a history of an illness possibly attributable to dengue virus infection. Our results show that there definitely is a risk for long-term expatriates to acquire (mostly non- or oligo-symptomatic) dengue infection, which might be important especially in the light of the supposed aetiology of DHF or DSS as a secondary infection with another dengue virus serotype.

Adolescent↗
PubMed1991

Comparison of neutralizing antigens of recent isolates of infections bursal disease virus.

Monoclonal antibodies (MAbs) to a local turkey isolate (QT-1) of infectious bursal disease virus (IBDV) were produced to identify the virus-specific neutralizing proteins. Radioimmunoprecipitation assays showed that all the MAbs were specific for major viral protein, VP2. Two of the MAbs neutralized the local turkey and chicken isolates along with a reference strain belonging to serotype 1 but not the reference strain of serotype 2. The reactivities of the neutralizing MAbs against two reference strains and some recent field strains of IBDV isolated in the province of Québec were studied by indirect enzyme-linked immunosorbent assay and virus neutralization tests. The variations in the reactivities of the MAbs observed suggest differences in the neutralizing epitopes of the different isolates. Competitive binding assay using the MAbs revealed the presence of a third epitope involved in the neutralization of IBDV belonging to serotype 1.

Animals↗