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PubMed1979

Zika virus infections in Nigeria: virological and seroepidemiological investigations in Oyo State.

A study of Zika virus infections was carried out in four communities in Oyo State, Nigeria. Virus isolation studies between 1971 and 1975 yielded two virus isolations from human cases of mild febrile illness. Haemagglutination-inhibition tests revealed a high prevalence of antibodies to Zika and three other flaviviruses used. The percentages of positive sera were as follows: Zika (31%), Yellow fever (50%), West Nile (46%), and Wesselsbron (59%). Neutralization tests showed that 40% of Nigerians had Zika virus neutralizing antibody. Fifty per cent of zika virus immune persons had neutralizing antibody to Zika alone or to Zika and one other flavivirus. A total of 121 sera had antibody to Zika virus; of these 48 (40%) also showed antibody to two other flaviviruses, and 12 (10%) had antibodies to three or more other viruses. The percentage of neutralizing antibodies to other flaviviruses in Zika virus immune sera was 81% to Dengue type 1, 58% to Yellow fever, 7% to Wesselsbron, 6% to West Nile and 3% to Uganda S.

Aedes↗
PubMed1990

Sandwich enzyme-linked immunosorbent assay (ELISA) for measuring the concentration of, and detection of antibodies to, Aujeszky's disease virus.

A double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed for measuring Aujeszky's disease virus (ADV) antigen concentration and an inhibition technique based on the former was developed for detection of antibodies to ADV. The results were checked by determining the cytopathic and serum neutralization titres. The correlation was satisfactory in both cases, with correlation coefficients above 0.8. When measuring ADV antigen concentration, the lower limit of detection was 10(3) TCID 50/0.2 ml. The sensitivity of ELISA in detecting antibodies to ADV was found to be superior to that of the serum neutralization test and, thus, enabled the testing of rabbit and guinea-pig sera.

Animals↗
PubMed1967

The incidence and significance of bovine herpesvirus (infectious bovine rhinotracheitis) antibodies in the sera of aborting cattle.

The results of bovine herpesvirus (IBR-IPV) neutralization tests conducted on the sera of 463 animals with a prior history of undiagnosed abortion and 331 control animals with no history of abortion are reported. One hundred and thirty-one (28.3 per cent) of the aborting and 105 (31.7 per cent) of the control animals, were found to harbour antibody to this virus. No significant seasonal or gestational incidence could be determined but some variation in the annual incidence was apparent. On the basis of these results it appears unlikely that this virus is responsible for a significant proportion of the undiagnosed cases of bovine abortion in Quebec and Ontario, where the animals tested were located. The problems involved in substantiating a diagnosis of abortion due to bovine herpesvirus are briefly discussed.

Abortion, Veterinary↗
PubMed2005

Molecular and seroepidemiologic studies of Enterovirus 71 infection in the State of Para, Brazil.

In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Para showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.

Acute Disease↗
PubMed2001

Epizootiological survey of hantavirus among rodent species in Ningxia Hui Autonomous Province, China.

Hantaviral antibodies were detected in the sera from Apodemus (A.) agrarius and A. peninsulae captured in Ningxia province, China by several different serological diagnostic methods. A total of 409 sera from rodent and insectivore species were collected in 1999 and examined by indirect immunofluorescent antibody assay (IFA). Among them, 19 of 191 (9.9%) sera of A. agrarius and 1 of 13 (7.7%) sera of A. peninsulae were positive for hantaviral antibodies. The other species (Rattus norvegicus, Mus musculus, Cricetulus triton, and Sorex cylindricauda) were negative. The reaction pattern of positive serum was characterized as scattered and granular virus antigens in the cytoplasm of hantavirus infected Vero E6 cells. Some of the A. agrarius sera positive for hantavirus were further examined by Western blotting (WB), enzyme-linked immunosorbent assay (ELISA), and the focus reduction neutralization test (FRNT). By WB, positive sera showed the same specific reaction pattern of baculovirus-expressed recombinant hantaviral nucleocapsid protein, as shown in hantavirus-immune serum. By ELISA, IFA-positive sera showed significantly higher optical densities (around 1.0) than the negative A. agrarius sera. Hantaan type hantavirus was neutralized with the positive sera. These results suggest that A. agrarius have hantavirus infection and may play a role as a reservoir animal for hantavirus in Ningxia Hui Autonomous Province, China.

Animals↗
PubMedDate not supplied

[Neutralizing antibodies to Coxsackie virus group B 1986-1988].

Presence of neutralizing antibodies to Coxsackie B viruses (CBV) 1-5 were examined in 2885 human sera by the neutralization test. The most frequently detected antibodies were to B4 viruses (in 1495 sera--51.82%) and to B3 (1371--47.52%). Antibodies to other serotypes were found in lower percentage: to B1 in 387 samples (13-41%), to B2 in 404 sera (14%) and in B5 in 332 sera (11.5%). Presence of neutralizing antibodies to human CBV in heart diseases were also analysed in 67 serum pairs. In this group of examinees the antibody titer dynamics was found in 41.79% sera.

Antibodies, Viral↗
PubMed1995

Experimentally induced "late-onset" mucosal disease--characterization of the cytopathogenic viruses isolated.

Antigenic and genetic analyses were performed in order to establish relationships between the noncytopathogenic (ncp) and the cytopathogenic (cp) bovine viral diarrhoea viruses (BVDV) involved in the induction of a case of experimentally induced "late-onset" mucosal disease (MD) symptoms. The persistent ncpBVDV, the cpBVDV used for superinfection (strain TGAC) and the virus isolates from faeces (cpX) were examined using an immunoplaque test (IPT) to distinguish between cp and ncp virus populations. The cp populations were cloned by plaque purification and found to be free of ncpBVDV when using the IPT. The cpBVDV clones and the persistent ncpBVDV were analysed in an enzyme immunoassay on heat-fixed infected cells (IM-EIA) and in a neutralization test using a panel of 27 monoclonal antibodies against the E0 (gp48) and E2 (gp53) viral glycoproteins. It was found that strain TGAC contained two antigenically distinct subpopulations of cpBVDV (TGAC-B1 and TGAC-B2). The endogenous ncpBVDV and the cpX clones had the same reactivity pattern in both tests. In addition, p80 gene duplications in the genomes of the cpBVDV clones were analysed using the polymerase chain reaction and subsequent restriction enzyme analysis of the amplicons. The clones analysed from TGAC-B1 and those from cpX had gene duplications of identical sizes showing the same restriction enzyme patterns. Our results suggest that the cpBVDV which finally lead to "late-onset" MD arose by recombination and/or by mutations of the cpBVDV used for superinfection.

Animals↗
PubMed1987

Rift Valley fever: a sero-epidemiological survey among pregnant women in Mozambique.

Rift Valley fever (RVF) causes abortion in sheep and cattle. However, the teratogenic and abortogenic potential of RVF in humans is not known. Sera from a total of 1163 pregnant women in Mozambique were tested for RVF virus antibodies by ELISA and 28 (2%) were found to be positive. Mothers experiencing fetal death or miscarriage (155) had the same RVF virus antibody prevalence as those with normal deliveries. Analysis of maternity histories showed some indication of increased fetal wastage among women positive for RVF virus antibody. The ELISA used in this study was compared with a plaque reduction neutralization test and found to be equally sensitive and specific for the detection of RVF virus IgG antibodies.

Abortion, Spontaneous↗
PubMed1977

Microimmunodiffusion test for detection of antibodies to infectious bovine rhinotracheitis virus in bovine serum.

A microimmunodiffusion test (MIDT) specific for detection of antibodies to infectious bovine rhinotracheitis (IBR) in bovine serum has been developed. The antigen used in the MIDT was prepared from IBR virus-infected Madin-Darby bovine kidney cells grown in tissue culture. The antigen was stable, and relatively high yields were obtained readily. Results of the MIDT were obtained within 48 hours and agreed with those of the serum-neutralization test.

Animals↗
PubMed1974

Rapid typing of herpes simplex virus strains using the indirect immunoperoxidase method.

The indirect immunoperoxidase technique with type-specific antisera was compared to kinetic neutralization for the typing of herpes simplex virus strains. There was complete agreement between the results obtained by kinetic neutralization and indirect immunoperoxidase. The indirect immunoperoxidase assay was far simpler to perform and interpret than the kinetic neutralization tests, and it offered a rapid means for the routine antigenic typing of herpes simplex isolates.

Animals↗
PubMed2004

Rabies neutralizing antibody detection by indirect immunperoxidase serum neutralization assay performed on chicken embryo related cell line.

The aim of this study was to evaluate the indirect immunoperoxidase virus neutralization (IPVN) and mouse neutralization test (MNT) to detect antibodies against rabies virus from vaccinated dogs and cattle. The IPVN was set up for the ability to measure 0.5 International Units/ml (IU) of antibody required by the World Health Organization and the Office International des Epizooties as the minimum response for proof of rabies immunization. IPVN was developed and standardized in chicken embryo related (CER) cell line when 141 dog and 110 cattle sera were applied by serial five-fold dilutions (1:5, 1:25, 1:125) as well as the positive and negative reference controls, all added in four adjacent wells, of 96-well microplates. A 50 microl amount of CVS32 strain dilution containing 50-200 TCID50/ml was mixed to each serum dilution, and after 90 min 50 microl of 3 x 10(5) cells/mlcell suspension added to each well. After five days of incubation, the monolayers were fixed and the IPVN test performed. The correlation coefficient between the MNT and IPVN performed in CER cells was r = 0.9949 for dog sera (n = 100) and r = 0.9307 for cattle sera (n = 99), as well as good specificity (94.7%), sensitivity (87.5%), and agreement (96.6%) were also obtained. IPVN technique can adequately identify vaccinated and unvaccinated animals, even from low-responding vaccinated animals, with the advantage of low cost and faster then MNT standard test.

Animals↗
PubMedDate not supplied

An indirect enzyme-linked immunosorbent assay (ELISA) for measuring antibodies in chickens infected with infectious bursal disease virus.

An immuno-enzyme assay for measuring infectious bursal disease antibodies in chickens is described. The test is performed rapidly after coating plates overnight with partially purified antigen prepared in cell culture. Coated plates can be stored for at last 4 months. The chromatographically purified rabbit anti-chicken immunoglobulin-G, conjugated to horseradish peroxidase, was used optimally at a dilution of 1:3,000. It could be stored for at least 10 months without a reduction in titer. The test is safe, highly reproducible, specific, and sensitive. Results can be read visually or by spectrophotometry. Antibodies could be detected as early as 4 days postinfection. Serum titers rose rapidly to high levels, ranging from 1:1,600 to 1:25,600 by one week postinfection. High titers persisted for up to one year. The results of this assay compare favorably with results obtained with the agar-gel precipitin and virus-neutralization tests.

Animals↗
PubMed2003

Production of neutralizing human monoclonal antibody directed to tetanus toxin in CHO cell.

By the fusion of lymphocytes from hyperimmunized people with heteromyeloma cells, 600 human hybridoma cell lines were generated. Even though seven cell lines produced antibodies against tetanus toxoid, only two antibodies from hybrid CH8 and CH5 only neutralized the tetanus toxin and completely protected the mice that had been challenged with the toxin even at the level of 90 mean lethal dose. The cDNA of light (L) chain and heavy (H) chain variable region was isolated, and then inserted into expression vectors containing human IgG constant regions. After transfection of the recombinant human IgG gene into Chinese Hamster Ovary (CHO) cells, transformants secreting the complete human antibody were selected. The recombinant human antibodies produced from CHO cells possessed neutralizing activity against tetanus toxin just like the original human antibodies produced from human hybridoma cell lines. Western blot analysis showed that rCH8 and rCH5 antibodies recognized the H chain of tetanus toxin and did not bind to its L chain. The neutralizing test showed that HmAb rCH5 had 4.55IU and HmAb rCH8 had 1.09IU/100 micro g of IgG, respectively. Mixing of the two HmAbs resulted in synergistic effects. On a weight basis (IU/100 micro g IgG), the highest potency values were obtained when the two HmAbs were combined in equal quantity. The neutralizing activity of rCH8 and rCH5 mixture was 6.94IU/100 micro g IgG.

Amino Acid Sequence↗
PubMed1990

Preparation and characterization of neutralizing monoclonal antibodies to feline calicivirus.

Fourteen neutralizing monoclonal antibodies (N-MoAbs) were prepared against the F4 strain of feline calicivirus (FCV), the prototype strain of FCV in Japan, and examined for their ability to neutralize FCV isolates. Neutralization-resistant variants of the F4 strain were selected under the presence of 4 individual N-MoAbs in cell culture systems and used in cross-neutralization tests and enzyme-linked immunosorbent assay with all of the 14 N-MoAbs. The results revealed the identification of at least two antigenic determinants on FCV F4: one being more broadly conserved among FCV isolates than the other. Usefulness of antigenic variants resistant to N-MoAbs for analysis of neutralization determinants on FCV was also demonstrated.

Antibodies, Monoclonal↗
PubMed1988

The development and standardization of an enzyme-linked immunosorbent assay for the detection of antibodies to bovine herpesvirus 2.

A single dilution enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to bovine herpesvirus 2 has been developed, standardized and compared with the virus neutralization test. The results of the two tests correlated well. A positive/negative threshold was established for the ELISA. The ELISA was reproducible, sensitive, rapid and specific.

Antibodies, Viral↗
PubMedDate not supplied

[Isolation and identification of the infectious bovine rhinotracheitis virus in a bovine fetus kidney (IBR/IPV)].

The authors describe the isolation and identification of a virus from bovine fetal kidney cells maintained in culture for 30 to 45 days. The virus was characterized as a herpesvirus of the infectious bovine rhinotracheitis in cell culture by the evidence of cytopathogenic effect in bovine kidney and testis cultures and serologically by a neutralization test using rabbit anti-infectious bovine rhinotracheitis sera.

Animals↗
PubMed2005

Vaccinia virus H3L envelope protein is a major target of neutralizing antibodies in humans and elicits protection against lethal challenge in mice.

The smallpox vaccine is the prototypic vaccine, yet the viral targets critical for vaccine-mediated protection remain unclear in humans. We have produced protein microarrays of a near-complete vaccinia proteome and used them to determine the major antigen specificities of the human humoral immune response to the smallpox vaccine (Dryvax). H3L, an intracellular mature virion envelope protein, was consistently recognized by high-titer antibodies in the majority of human donors, particularly after secondary immunization. We then focused on examining H3L as a valuable human antibody target. Purified human anti-H3L antibodies exhibited substantial vaccinia virus-neutralizing activity in vitro (50% plaque reduction neutralization test [PRNT50] = 44 microg/ml). Mice also make an immunodominant antibody response to H3L after vaccination with vaccinia virus, as determined by vaccinia virus protein microarray. Mice were immunized with recombinant H3L protein to examine H3L-specific antibody responses in greater detail. H3L-immunized mice developed high-titer vaccinia virus-neutralizing antibodies (mean PRNT50 = 1:3,760). Importantly, H3L-immunized mice were subsequently protected against lethal intranasal challenges with 1 or 5 50% lethal doses (LD50) of pathogenic vaccinia virus strain WR, demonstrating the in vivo value of an anti-H3L response. To formally demonstrate that neutralizing anti-H3L antibodies are protective in vivo, we performed anti-H3L serum passive-transfer experiments. Mice receiving H3L-neutralizing antiserum were protected from a lethal challenge with 3 LD50 of vaccinia virus strain WR (5/10 versus 0/10; P < 0.02). Together, these data show that H3L is a major target of the human anti-poxvirus antibody response and is likely to be a key contributor to protection against poxvirus infection and disease.

Administration, Intranasal↗
PubMedDate not supplied

[Development of test systems of immunoenzyme analysis for the detection of antibodies to the transmissible gastroenteritis virus of swine].

Two variants of enzyme immunoassay (EIA) using purified swine transmissible gastroenteritis virus antigen for sensitization of the solid phase and using infected cells on the solid phase have been developed for quantitation of specific antibodies to swine transmissible gastroenteritis (STG) virus. Both variants of the method were found to have approximately similar sensitivity and to be highly specific. The developed EIA proved to be approximately 100 times as sensitive as neutralization test. The optimal concentration of purified antigen for sensitization of microplates, as well as the multiplicity of infection of the heterologous cell culture grown in microplate wells have been determined. The above methods may be widely used in virological and epizootiological studies.

Animals↗