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PubMed1985

Mapping of type 1 poliovirus neutralization epitopes.

Several independently variable neutralization epitopes were identified on type 1 poliovirus by testing various field isolates with a panel of homotypic monoclonal antibodies. According to their distribution among viruses tested, neutralization epitopes were classified as strain-specific or variable (V) and cross-reacting or constant (K). Operational, relationship between different neutralization epitopes was analysed by selecting mutants resistant to neutralization with monoclonal antibodies from wild Mahoney and attenuated Sabin type 1 poliovirus. The results of this study and their implication in the characterization of poliovirus antigenic structure by neutralization epitope formulae is discussed.

Antibodies, Monoclonal↗
PubMed1979

The virus neutralizing activity of antibodies specific to the envelope and nucleocapsid of equine herpesvirus type 1.

Antibodies specific to the envelope or nucleocapsid of the Kentucky-D strain of equine herpesvirus type 1 were isolated from convalescent horse serum by immunoadsorption on cyanogen bromide-activated Sepharose conjugated with equine herpesvirus type 1 envelopes or nucleocapsids, with subsequent elution by glycine buffer. In double immunodiffusion and immunolectrophoresis reactions, the eluted proteins appeared to belong to the IgG fraction of horse serum. Antibodies directed against the viral envelope neutralized equine herpesvirus type 1 in a plaque neutralization test, while antibodies against the nucleocapsid showed no virus neutralizing activity.

Animals↗
PubMed1981

Immunogenicity of influenza A/USSR (H1N1) subunit vaccine in unprimed young adults.

Purified subunit vaccines (HANAflu) containing 20 microgram hemagglutinin of influenza A/USSR/90/77 (H1N1) alone or with 1-5% whole virus were compared to commercially available vaccines for reactogenicity and immunogenicity in unprimed young adults. Reactions to all vaccines were minimal. Sera from volunteers who received two intramuscular doses of vaccine or placebo were tested by hemagglutination-inhibition and neutralization tests. HANAflu with 1 microgram (5%) whole virus added was not different in immunogenicity from commercial vaccine. Both commercial vaccine and HANAflu with 1 microgram whole virus added gave higher seroconversion rates and more neutralization titers greater than or equal to 4 log2 than HANAflu alone and HANAflu + 0.2 microgram (1%) whole virus. Thus, the HANAflu subunit vaccine alone was less immunogenic than commercial vaccine in unprimed persons. However, addition of 1 microgram (5%) whole virus, but not 0.2 microgram (1%), eliminated this difference, There may be a role for addition of small amounts of whole virus to subunit influenza vaccines to overcome lower immunogenicity in unprimed populations.

Adolescent↗
PubMed1977

Isfahan virus, a new vesiculovirus infecting humans, gerbils, and sandflies in Iran.

The characteristics and ecology of Isfahan virus, a new vesicular stomatitis virus (VSV) serotype, are described. Two strains of the agent were isolated from pools of Phlebotomus papatasi collected in Iran in 1975. Its animal pathogenicity, growth rate, cytopathic effect, and plaque morphology are similar to those of the other VSV serotypes. Electron microscopic examination of the virus demonstrated a bullet shape, the presence of truncated particles and maturation at plasma membranes. Antigenic relationships between Isfahan virus and three other VSV serotypes (Cocal, Piry, and Chandipura) were demonstrated by complement fixation or neutralization tests. A high prevalence of Isfahan neutralizing antibodies was found in human sera from several regions of Iran, suggesting that the virus may be of some public health importance. All of the residents over 5 years of age in the village where the virus was isolated had been infected. Neutralizing antibodies to Isfahan virus were also found in sera of Iranian gerbils but not in domestic animals. Results of this study suggest that the ecology of Isfahan virus is distinct from the other VSV serotypes and involves chiefly humans, gerbils, and sandflies, a pattern also observed with cutaneous leishmaniasis and sandfly fever in Iran.

Animals↗
PubMed1999

Detection of neutralizing antibodies against alpha-toxin of different Clostridium septicum strains in cell culture.

Clostridium septicum, a ubiquitious organism, is the pathogen which causes the classical malignant edema after injuries. Because of its strong cytotoxic alpha-toxin, infections are often lethal. To prevent losses in animals, vaccination with alpha-toxoid vaccines is carried out. Quality control of the vaccines is done by a neutralization test in mice. A cytotoxin test and as an alternative method to detect neutralizing antibodies, a cytotoxin inhibition test was standardized. In the studies, alpha-toxin of the C. septicum reference strain (NC 547) from the National Collection of Type Cultures was compared with alpha-toxin of a field strain from an outbreak in Germany. Sera from five heterologous polyvalent and three monovalent vaccines from eight rabbit groups were available. Each vaccination had been carried out according to the procedure of the German Pharmacopoeia. In three out of the five sera of the groups vaccinated with the heterologous polyvalent vaccine, cytotoxin neutralizing antibodies were detected. High antibody titers were observed in sera of rabbits vaccinated with a vaccine of strain NC 547, lower titers in the sera of rabbits vaccinated with a vaccine of the field strain. No cytotoxin neutralizing antibodies could be found in the sera of rabbits vaccinated with the monovalent C. chauvoei vaccine. The toxins of all strains showed the same ranking of the vaccines. Vaccines which caused high antibody titers in the animals were detected by all toxins as such, as well as vaccines which had medium or low antibody inducing capacity. The results were independent of the C. septicum strain used for the production of alpha-toxin.

3T3 Cells↗
PubMed1998

Mayaro virus fever in French Guiana: isolation, identification, and seroprevalence.

This paper reports the first isolation of Mayaro (MAY) virus from a patient infected in French Guiana. The identification was initially performed using immunofluorescent antibody testing with specific mouse antibody, and confirmed by plaque-reduction neutralization testing and reverse transcription-polymerase chain reaction. To determine if MAY virus infection is widespread in French Guiana, a serosurvey was performed to determine the prevalence of antibody to this virus in various ethnic groups and areas of French Guiana. Human sera (n = 1,962) were screened using the hemagglutination inhibition (HI) test. To determine whether MAY virus circulates in the rain forest, a serosurvey in monkey populations was performed. Monkey sera (n = 150) were also screened for antibody to MAY virus using HI testing. Of the human sera tested, 6.3% were positive for anti-MAY virus antibodies. Significant differences in MAY virus seroprevalence between different age groups were observed. Seroprevalence rates increased with age, with a large increase in people 10-19 years of age in comparison with those less than 10 years of age. After adjustment for age, significant differences were also found between places of residence. The prevalence of anti-MAY virus antibody was higher in people living in contact with the forest, especially in the Haut Oyapock area (odds ratio [OR] = 97.7, 95% confidence interval [CI] = 48.2-197.9) and along the Maroni River (OR = 39.7, 95% CI = 20.6-76.6). The ethnic differences observed in this study were probably due to differences in residence. Among monkeys, higher seroprevalence rates were found in Alouatta seniculus (66.0%) than in Saguinus midas (18.2%). Among Alouatta, the seroprevalence increased significantly with weight (and therefore with age). This study indicates that MAY virus is present in French Guiana, and human infections occur in areas where people live near the tropical rain forest.

Adolescent↗
PubMed1981

Powassan virus infection in snowshoe hares (Lepus americanus).

Sera from snowshoe hares (Lepus americanus) trapped near Rochester, Alberta, Canada were tested for Powassan virus antibody by the constant virus/serum dilution neutralization test. Of 1264 serum samples tested, 137 had an antibody titer of at least 1:4 for Powassan virus. Ten hares were inoculated with Powassan virus in the laboratory. Viremia lasted 4-5 days and ceased with the appearance of Powassan antibody in the serum. Neutralizing antibody reached a peak titer of 1:119 on day 15 post-inoculation and was still detectable 13 months post-inoculation.

Alberta↗
PubMed1993

Antigenicity of a candidate varicella-zoster virus glycoprotein subunit vaccine.

A 1642 bp DNA fragment, encoding the N-terminal region and 511 amino acid residues of varicella-zoster virus (VZV) glI gene, was inserted into vaccinia virus genome. The expression of recombinant vaccinia virus (designated VVTgpI-511) yielded the synthesis of a 60 kDa protein species which was processed to a secretory 76 kDa polypeptide (designated TgpI-511). The antigenicity of this protein was examined by subcutaneous inoculation of one rabbit with 100 micrograms purified TgpI-511 in the Ribi adjuvant system. The animal was boosted 3 weeks after the initial inoculation and antisera were tested 7 days after the last injection by immunoprecipitation and neutralization tests. The results showed that rabbit antibodies to TgpI-511 (RAnti-TgpI-511) were reactive with purified TgpI-511 as well as native gpI in VZV-infected cells. In addition, TgpI-511 was capable of eliciting complement-dependent VZV neutralizing antibodies. These results suggested that the purified preparation of TgpI-511 may have the potential to be used as a candidate VZV subunit vaccine.

Animals↗
PubMedDate not supplied

Simplification of immune adherence hemagglutination test for detection of rabies antibodies in human serum.

In the present work the immune adherence hemagglutination test (IAHA) was standardized in a simplified procedure. This test showed good reproducibility, better than the classical mice serum neutralization test (SN). The tests showed high correlation degree: high titers in one test corresponded to high titers in the other one, and the same occurred with low titers. The IAHA test is extremely simple, fast to perform, and of low cost when compared to tests such as SN or indirect immunofluorescence (IIF). It also proved to be useful in less sophisticated laboratories or even as a screening test for the titration of rabies antibodies.

Antibodies, Viral↗
PubMed1984

Microneutralization test in PK(15) cells for assay of antibodies to louping ill virus.

A microneutralization test in PK(15) cells was developed to measure the neutralizing antibody response of a group of ponies experimentally challenged with louping ill virus. Viral cytopathic effect was maximal after 6 days of incubation, at which point titration endpoints were clear-cut and readily determinable. The assay compared favorably with the mouse neutralization test for accuracy and ease of performance.

Animals↗
PubMed2001

Seroprevalence of antibodies against equine arteritis virus in horses residing in the United States and imported horses.

OBJECTIVE: To compare seroprevalence of antibodies against equine arteritis virus (EAV) in horses residing in the United States with that of imported horses. DESIGN: Serologic survey. SAMPLE POPULATION: Serum samples from 364 horses on 44 equine operations in California and 226 horses imported from various countries. PROCEDURE: Serum samples were collected from each imported horse and from up to 20 horses on each operation. For resident horses, the number of sampled horses on each operation was determined on the basis of the number of horses on the operation. Samples were tested for antibodies against EAV by use of a serum neutralization test. RESULTS: 1.9% of resident horses and 18.6% of imported horses were seropositive to EAV, including 16.1% of imported stallions. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that the EAV seroprevalence of horses residing in California is considerably lower than that of imported horses, including imported stallions.

Animals↗
PubMed1997

Neutralizing antibodies to type 1 and 2 bovine viral diarrhea viruses: detection by inhibition of viral cytopathology and infectivity by immunoperoxidase assay.

Neutralizing antibodies to type 1 and 2 bovine viral diarrhea virus (BVDV) strains were measured by a microtiter virus neutralization test (MVNT) in cell culture. Antibodies (neutralizing) were detected by inhibition of viral infectivity, by the absence of viral cytopathology for cytopathic strains, or by immunoperoxidase staining for noncytopathic strains. The immunoperoxidase-stained monolayers could be detected without the aid of light microscopy. Twenty BVDV strains were used as challenge viruses in the in vitro MVNT, including 14 type 1 and 6 type 2 strains. Representative noncytopathic and cytopathic strains of both types were used. Positive control serum samples available for diagnostic testing contained both type 1 and type 2 BVDV antibodies. There did not appear to be major differences in antibody titers among the respective type strains, regardless of biotype (cytopathic or noncytopathic). In a study with sera from calves receiving a modified live virus or inactivated BVDV vaccine, the calves receiving type 1 strains responded with higher antibody titers to type 1 strains than to type 2 strains.

Animals↗
PubMed1986

Epidemiological investigations following an outbreak of hemorrhagic fever with renal syndrome in Greece.

Epidemiological investigations were conducted following an outbreak of hemorrhagic fever with renal syndrome (HFRS) which occurred in the state of Epirus, northwestern Greece, in July and August 1983. A total of 8 patients were hospitalized during the outbreak; 3 were severely ill and 1 died. A serosurvey made in May 1984 sampled 184 of the approximately 400 residents of the village of Tsepelovo, where 4 patients resided, and found 12 (6.5%) persons, including convalescent sera from 4 patients, with antihantaviral antibody by immunofluorescent antibody (IFA) tests. Small mammal collections found house rats common in the village, but none exhibited anti-hantaviral antibody. Collections in nearby fields and mountains found Apodemus flavicollis rodents common, and 2 (6%) of 33 captured had high IFA anti-hantavirus antibody. Virus isolation attempts from rodent tissues were unsuccessful. Testing of convalescent patients' sera by IFA and plaque reduction neutralization tests indicated that the etiological agent was neither Puumala virus nor Seoul virus, but appears to be a strain of Hantaan virus or perhaps a new virus. The rodent host of this virus may be A. flavicollis, and the distribution of this species corresponds with previously reported cases of severe HFRS described elsewhere in central Europe.

Adolescent↗
PubMed2006

[Tick-borne encephalitis (TBE) with special emphasis on infection in horses].

The tick-borne encephalitis (TBE), also known as early summer meningo-encephalitis, is a geographically limited virus infection transmitted mainly by ticks. The importance of TBE is largely underestimated. The causative agent TBE-Virus (TBEV) is grouped into the genus Flavivirus of the virus family Flaviviridae. Clinical disease including fatal outcomes has been described for men and dogs. With regard to horses only a limited number of case reports is available. In a study performed at the Institute of Virology, Justus-Liebig-University Giessen serum samples from the German endemic region of Marburg-Biedenkopf were tested for antibodies against TBEV. From 240 sera tested 7 (2.9%) were regarded as positive in a serum neutralization test (SNT). In an ELISA, performed in parallel to confirm the SNT results, 5 out of 7 positive sera from the SNT were also positive. The remaining two samples with low SNT-titres and all sera from horses negative in the SNT were also negative in the ELISA. This article is focussed on TBE of horses. In this context different aspects of TBE are included such as properties of the causative agent, interactions between causative agent, host animals and environment, spread of TBEV, pathogenesis, clinical symptoms, diagnosis and control.

Animals↗
PubMed1989

Improved colorimetric assay for detecting influenza B virus neutralizing antibody responses to vaccination and infection.

An automated neutralization test for influenza B virus is described in which antibody titers are determined according to the release of neutral red from infected or uninfected cells of the Madin-Darby canine kidney line. Endpoints are determined in a standard enzyme-linked immunosorbent assay reader. The test requires no expensive immunologic reagents and was used to evaluate responses to both vaccination and natural infection against influenza B virus. Overall responses to vaccination were comparable with those obtained by hemagglutination inhibition, using Tween-ether-split influenza B/Ann Arbor/1/86 virus as the antigen (the HI-TE test). The sensitivities of neutralization responses compared with those obtained by the HI-TE test for two vaccines were 88 and 89%; the specificities were lower at 61 and 60%, respectively. Responses to vaccination, measured by hemagglutination inhibition, were significantly higher with split virus compared with whole virus. However, seroconversion by both the HI-TE and neutralization tests was observed in 5 of 10 individuals from whom virus was detected by either culture of nasal or throat washings or the presence of antigen from immunofluorescence in cells from nasal washings.

Animals↗
PubMed1988

Antigenic variation of equine infectious anemia virus as detected by virus neutralization. Brief report.

The antigenic structure of 16 viruses isolated from four horses which were inoculated with a clone of equine infectious anemia (EIA) virus was compared by the neutralization test. The antigenic structure of viruses isolated after development of neutralizing antibody differed from virus to virus. Back mutation of the antigenic structure was also demonstrated by serial passage of the virus in horses. These results suggest that EIA virus is subject to multidirectional antigenic variation. The possibility that the variants originated in the heterologous virus population in the inoculum seems to be unlikely since the virus used for the primary inoculation was cloned by three repeated high-limiting dilutions.

Animals↗
PubMed1984

Plaque assay of equine influenza virus.

ESK cells, a stable cell line derived from a swine embryo kidney, were found to be a good medium for plaque formation of the Prague and Miami strains of equine influenza virus. Factors influencing the plaque formation were investigated and a plaque assay for these viruses was worked out. The method is not only simple enough for routine use, but also is as sensitive as the egg inoculation method. The method was readily adapted for a neutralization test.

Animals↗
PubMedDate not supplied

Reactivity of anti-human rotavirus VP4 neutralizing monoclonal antibodies with animal rotaviruses and with unusual human rotaviruses having different P and G serotypes.

The reactivity of five anti-human rotavirus VP4 neutralizing monoclonal antibodies (N-mAb) with 20 animal rotavirus strains and three unusual human rotavirus (HRV) strains was investigated. Five N-mAb prepared previously by the immunization of mice with HRV were employed in this study. They were found to neutralize HRV belonging to P types 4, 6 and 8, which were designated according to P (or VP4) type nomenclature proposed by Estes and Cohen (1989). A porcine rotavirus strain Gottfried was reactive with four of the five mAb both in neutralization tests and in ELISA. However, no other animal rotaviruses were neutralized by any of the mAb. Fourteen animal strains were reactive with only one or two mAb in ELISA, and five animal strains were inactive with all. These results indicate that neutralization epitopes on VP4 are serologically considerably different between HRV (except for unusual Indonesian strains 57M and 69M) and animal rotaviruses (except for porcine rotavirus strain Gottfried).

Aged↗