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PubMed1988

Prevalence of antibodies to seven viruses in a flock of ewes in Minnesota.

Blood samples were collected from a flock of healthy ewes at a University of Minnesota research station. Sera from these blood samples were tested for antibodies against 7 viruses, using 3 tests (eg, virus-neutralization test for bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, bovine adenovirus type 3, and bovine respiratory syncytial virus; hemagglutination inhibition test for parainfluenza virus type 3; and agar-gel immunodiffusion test for lentivirus of ovine progressive interstitial pneumonia and bluetongue virus). The number of seropositive ewes for each antibody type were 1 of 377 (0.3%) for bovine viral diarrhea virus, 2 of 377 (0.5%) for infectious bovine rhinotracheitis virus, 29 of 378 (7.6%) for bovine adenovirus type 3, 200 of 378 (52.5%) for bovine respiratory syncytial virus, 273 of 373 (71.7%) for parainfluenza virus type 3, and 210 of 379 (55%) for ovine progressive pneumonia virus. All ewes were seronegative for bluetongue virus antibodies.

Adenoviridae↗
PubMed1989

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

The relationship between the two estimates of genetic variation at the DNA level, namely the number of segregating sites and the average number of nucleotide differences estimated from pairwise comparison, is investigated. It is found that the correlation between these two estimates is large when the sample size is small, and decreases slowly as the sample size increases. Using the relationship obtained, a statistical method for testing the neutral mutation hypothesis is developed. This method needs only the data of DNA polymorphism, namely the genetic variation within population at the DNA level. A simple method of computer simulation, that was used in order to obtain the distribution of a new statistic developed, is also presented. Applying this statistical method to the five regions of DNA sequences in Drosophila melanogaster, it is found that large insertion/deletion (greater than 100 bp) is deleterious. It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.

Animals↗
PubMed1988

Toxin-neutralizing antibodies in patients with pertussis, as determined by an assay using Chinese hamster ovary cells.

Antibodies to pertussis toxin were measured by a neutralization test (Chinese hamster ovary cell assay) in paired serum samples from 122 patients with whooping cough. The results were compared with previously published titers of IgG, IgM, and IgA measured by ELISA. Significant (fourfold or more) increases in neutralizing antibodies developed in 69 patients. Sixty-eight of them also had significant increases in at least one antibody class as measured by ELISA. Seventeen patients had significant increases in at least one antibody class without increases in neutralizing antibodies. All 163 serum samples with neutralizing antibodies also had detectable IgG, whereas 14 samples with IgG and 18 with IgM were negative by neutralization test. Thus, toxin-neutralizing serum antibodies develop in most patients with pertussis. Our ELISA, however, was more sensitive in detecting low levels of antibodies and in demonstrating significant increases between acute- and convalescent-phase serum samples.

Adolescent↗
PubMed1984

Comparison of a modified counterimmunoelectrophoresis test and a microimmunodiffusion test for detection of pseudorabies virus antibodies in porcine sera.

The correlation of a modified counterimmunoelectrophoresis (CIE) test and a microimmunodiffusion test for detecting pseudorabies virus antibodies in porcine sera was investigated, using as reference a standard virus neutralization test. The counterimmunoelectrophoresis test exhibited a sensitivity comparable to the microimmunodiffusion test but was not as sensitive as the virus neutralization test. The best feature of the modified counterimmunoelectrophoresis test is that it is a rapid test. It provides an alternative to currently used diagnostic tests for detection of pseudorabies virus antibodies in sera from field reared and experimentally reared swine exposed to pseudorabies virus.

Animals↗
PubMed1969

Comparison of the catalytic and immunological properties of beta-glucosidases from three strains of Saccharomyces lactis.

beta-Glucosidase from Saccharomyces lactis strains Y-123 (B(h)), Y-14 (B(m)), and Y-1057A (B(1)) was partially purified. The pH optima, Michaelis constants, and activation energies were determined for the hydrolysis of p-nitro-phenyl-beta-d-glucoside by each of the enzymes. Differences among these constants were not enough to account for the low specific activity of beta-glucosidase in strains Y-14 and Y-1057A. Enzyme-inhibitor constants were measured for a series of alkyl and aryl glucosides. In general, the three enzymes are arylglucosidases. Tris(hydroxymethyl)-aminomethane inhibited all three enzymes in an uncompetitive fashion. The inhibition was antagonized by Mg(++). An antiserum was prepared to the highly purified (200-fold) beta-glucosidase from strain Y-123. The nature and degree of cross-reaction between the three beta-glucosidases was investigated by double diffusion in agar and neutralization tests. Spur formation in the immunodiffusion tests and similar equivalence points in the neutralization tests indicated a strong degree of cross-reaction between the three enzymes. The ratio of enzyme activity to antigenicity was used to compare the relative molecular activity of beta-glucosidase in the three strains. Each strain produced the same amount of beta-glucosidase per milligram of cell protein. The results are consistent either with a lower turnover number for the beta-glucosidase in strains Y-14 and Y-1057A or with the production of beta-glucosidase with a "normal" turnover number and enough cross-reacting material to effectively reduce the specific activity to the observed levels.

Antigens↗
PubMed1987

Comparison of competitive and indirect enzyme-linked immunosorbent assays for detection of bluetongue virus antibodies in serum and whole blood.

An indirect (I) enzyme-linked immunosorbent assay (ELISA) and a competitive (C) ELISA, using a group-specific monoclonal antibody against bluetongue virus (BTV), are described for the detection of antibodies to BTV in cattle and sheep sera. The performance of these assays in detecting anti-BTV antibody in sequential serum samples and eluates from whole blood (WB) dried on filter paper from three calves and four sheep experimentally infected with type 10 BTV was evaluated. The C-ELISA was superior to the I-ELISA in the detection of anti-BTV antibody in the sera and WB samples from both cattle and sheep early after infection with BTV. BTV antibodies were demonstrable by C-ELISA in all the bovine and ovine sera and WB eluates by 9 days postinfection; whereas the I-ELISA results for sheep sera and WB eluates were similar, anti-BTV antibody was not detected in bovine serum and WB eluates until 26 and 14 days postinfection, respectively. While both ELISAs proved reliable, under the present test conditions involving detection of early postinfection reactions of experimentally infected animals, the C-ELISA was always as sensitive or more sensitive than the standard agar gel immunodiffusion test, the modified complement fixation test, and the plaque neutralization tests in the detection of anti-BTV antibodies. Unlike observations with the immunodiffusion test, no reaction was seen between BTV antigen and bovine epizootic hemorrhagic disease virus antiserum in either ELISA. The results suggest that either ELISA may be suitable for routine diagnostic testing and may have the potential to replace other tests for detection of anti-BTV group-specific antibodies and that the C-ELISA may have the most potential.

Animals↗
PubMed1993

Evaluation of serological pseudorabies tests for the detection of antibodies during early infection.

Six enzyme-linked immunosorbent assays, a latex agglutination test, and the standard microtitration serum virus neutralization test were compared for their ability to detect antibodies against pseudorabies virus (PRV) during the early stages of infection. Thirty-five pigs were infected intranasally with 10(5)-10(7) TCID50 of either the Iowa 4892 pneumotropic or the Becker strain of PRV. Blood samples were drawn from experimentally inoculated animals on days 4-10, 14, and 21 postchallenge. Test sensitivity estimates and comparisons among tests were made for each sampling day over the 21-day monitoring period. Results of this study demonstrated differences among tests in 1) the time from inoculation to initial antibody detection, 2) the time to detect > or = 95% of the infected pigs, and 3) the time from initial antibody detection to determination of > or = 95% as positive. By day 10 postchallenge, no statistically significant difference in diagnostic sensitivity was observed among the 8 tests compared in the study.

Animals↗
PubMedDate not supplied

[Analysis of the antigenic properties of strains of influenza virus that caused the epidemic of 1974-1975].

The etiology of influenza epidemic of 1974-1975 in the USSR was studied. The influenza viruses isolated from patients in the period of the 1974-1975 epidemic were tested in the hemagglutination-inhibition, neuraminidase activity-inhibition, immunoadsorption and biological neutralization tests. The majority of the strains tested were shown to be similar to the new antigenic variant A/Port Chalmers/1/73. It means that the strains of A/Port Chalmers/1/73 variant occurred epidemically in this region only in the winter of 1974-1975. The greatest differences between the new isolates and previously circulating strains of A/England/42/72 variant were observed in biologic neutralization tests.

Antigens, Viral↗
PubMed1973

Resistance of mice to infection with Friend disease virus after subcutaneous injection of Friend virus and Friend spleen cells.

Swiss mice injected subcutaneously with suspensions of spleen cells or an extract of spleens from mice infected with Friend virus develop resistance to subsequent intravenous inoculation of Friend virus. A single injection of either Friend virus or Friend cells induces resistance. Immunized mice display resistance when challenged 6 months after immunization and survive for at least 20 weeks after infection. Neutralization tests indicate that serum, but not lymphoid cells of resistant animals, can neutralize Friend virus. In vitro neutralization tests indicate that residence of virus within the peritoneal cavity of immune mice for 1 h sharply reduces the infective titer of the virus.

Animals↗
PubMed1988

Immune inhibition of virus release from herpes simplex virus-infected cells by human sera.

Human sera contain antibody (IVR antibody) which will inhibit the release of herpes simplex virus type 1 from virus-infected cells. This antibody activity was removed by adsorption of sera with virus-infected cell extract. There was a positive correlation between IVR and neutralizing antibody activity, particularly when measured by augmented neutralization test; measurement of IVR antibody was equally as sensitive as measurement of neutralizing antibody by augmented neutralization test. IVR antibody levels provided indication of a history of recurrent herpes labialis, the pattern of antibody response following primary herpetic infection, and indication of response to Skinner herpes vaccine in human subjects. It is suggested that consideration should be given to measurement of IVR antibody in both clinical and epidemiological studies of herpes and other virus infections.

Antibodies, Viral↗
PubMed1987

A dot-immunobinding assay on nitrocellulose with psoralen inactivated Herpesvirus simiae (B virus).

An enzyme-immunoassay performed with Herpesvirus simiae (B virus) and H. simplex antigens inactivated with a psoralen derivative and long-wavelength ultraviolet light irradiation is described. Although B virus is a known human pathogen requiring extreme care in its handling, the use of inactivated antigens in the test allows its performance without biosafety containment. The test utilizes nitrocellulose sheets dotted with antigen for the assay of antibody against B virus in nonhuman primate sera. Antigen-antibody complexes are detected visually as red dots by the use of enzyme-conjugated antiglobulin second antibody and a substrate that produces an insoluble product. The test is more rapid, sensitive and specific than the serum neutralization test it is intended to replace. Of 150 macaque monkey sera tested, 83 were negative by the enzyme and neutralization tests, 56 were positive by both tests and 11 were positive by enzyme-assay but negative by neutralization. Positive sera reacted with both simian and human viral antigens in the enzyme assay but with greater intensity against B virus. Absorption with H. simplex removes reactivity with this virus without reducing the B virus response.

Antibodies, Viral↗
PubMedDate not supplied

[Virological study of cases of sandfly fever in Afghanistan].

Three strains (Af-1008, Af-1038, and Af-130) of Neapolitan sandfly fever virus (NSFF) and 2 strains (Af-1028 and Af-83) of Sicilian sandfly fever virus (SSFF) were isolated from febrile patients among soldiers of the limited military contingent of Soviet troops in Afghanistan in May-August, 1986-1987. The viruses were isolated in neonate mice and identified by indirect immunofluorescence, complement-fixation tests and plaque reduction neutralization test in Vero E6 and SPEV cells. The new NSFF strains in serological tests differed slightly from the original Sabin strain and completely differed from Toskana virus. In the examinations of 104 paired sera from convalescents, 87 subjects showed a rise in antibody titres either to NSFF or to SSFF virus, and 16 patients had antibodies to both viruses but without any rises in titre. Among 60 subjects with a presumable diagnosis of sandfly fever 12 persons had an antibody No information on isolation of sandfly fever viruses in Afghanistan has been available hitherto.

Afghanistan↗
PubMed1987

Human rabies immunoglobulin assayed by the rapid fluorescent focus inhibition test suppresses active rabies immunization.

The rabies antibody content of each of ten lots of human rabies immunoglobulin was titrated by both the mouse neutralization test and the rapid fluorescent focus inhibition test. The two tests did not give comparable results, the antibody titres obtained by the mouse neutralization test being 1.4-9.6 times higher than those obtained by the rapid fluorescent focus inhibition test. This titre difference was associated with a consistently lower antibody response in human volunteers who had received post-exposure rabies vaccine treatment which included the administration of RIG assayed by the RFFIT.

Adult↗
PubMed1977

[Immunologic transformation against pertussis in children following a second revaccination with ADPT-vaccine].

Immunological reconstruction was studied in children aged 6 years after the second revaccination with absorbed, pertussis-diphtheria-tetanus vaccine (APDT) in a strictly controlled trial. Antipertussis protective antibodies were determined in the sera in the passive hemagglutination test and the antigen neutralization test, whose results were characterized by the following regularities: the average (1:160--1:640) and the high (1:1280 and over) antibody titres were recorded 1 to 1.5 months after the vaccination in 46.9--48.9% of the persons vaccinated. Determination of the changes of the immunoglobulins A, M, and G at various periods after the second revaccination demonstrated that 1 to 1.5 months after the revaccination (that is at the peak of the antipertussis antibodies formation) 55.7--50.0% of the children displayed an elevation of the IgA and IgM against the background of the IgG reduction in 69.7% of cases.

Antibodies, Bacterial↗
PubMed1987

A test of neutral molecular evolution based on nucleotide data.

The neutral theory of molecular evolution predicts that regions of the genome that evolve at high rates, as revealed by interspecific DNA sequence comparisons, will also exhibit high levels of polymorphism within species. We present here a conservative statistical test of this prediction based on a constant-rate neutral model. The test requires data from an interspecific comparison of at least two regions of the genome and data on levels of intraspecific polymorphism in the same regions from at least one species. The model is rejected for data from the region encompassing the Adh locus and the 5' flanking sequence of Drosophila melanogaster and Drosophila sechellia. The data depart from the model in a direction that is consistent with the presence of balanced polymorphism in the coding region.

Alcohol Dehydrogenase↗
PubMedDate not supplied

[Some experimental data on the seroprophylaxis of tetanus].

The survival time of tetanus heterologous antitoxins, crude or digested, has been controlled by indirect haemagglutination (I.H.A.) and neutralization tests in guinea pigs and rabbits. Digested antitoxins are demonstrable in guinea pigs up to the 8th day, in rabbits only during the first day. They reach the highest level 24 hours after the injection: tested with I.H.A. show a good correlation with the quantity of injected antitoxin. In the sera of three wounded subjects, treated with Ig or digested horse antitetanic serum, after 24 hours the I.H.A. test was negative, while the neutralizing antibody titer was equal to 0.1/0.01 I.U./ml. These contrasting results are probably due to circulating Fab' gragments from decaying tetanus antitoxins.

Animals↗
PubMed1982

Improved yields and assay of simian varicella virus, and a comparison of certain biological properties of simian and human varicella viruses.

Studies were performed to define conditions under which propagation, assay and stabilization of the Delta herpesvirus (DHV) strain of simian varicella virus might be improved, and to compare biological properties of DHV with those of human varicella zoster virus (VZV). A mycoplasma contaminant was successfully eliminated from the DHV seed virus by treatment with a specific anti-serum. DHV was found to replicate more efficiently in the BS-C-1 line of African green monkey kidney cells than in Vero cells, and seed virus preparations in the form of virus-infected cells were produced which had infectivity titers greater than or equal to 1 X 10(6) p.f.u./ml. Greater yields of virus were produced in cultures infected as dispersed cells than as preformed monolayers. Infectious DHV could be released from host cells by sonic treatment of heavily infected cultures at 48 h post infection. Certain agents reported to enhance replication of herpes viruses (caffeine, carbaryl, the tumor promoter 12-0-tetra-decanoyl-phorbol-13-acetate, and DEAE-dextran) had no enhancing effect on replication of DHV. However, DEAE-dextran in the maintenance medium enhanced spontaneous release of DHV into culture fluids. Plaquing efficiency and plaque size of DHV were greater in BS-C-1 than in Vero cells, and plaque assays and plaque reduction neutralization tests were developed in this cell system using a solid overlay medium with neutral red vital stain. Neutralization of DHV was markedly enhanced by fresh guinea pig complement. The newly developed neutralization test demonstrated more vigorous antibody responses to DHV in active and latent VZV infections than were demonstrated with previous procedures. In addition to their preferential growth in monkey and human cells respectively, DHV and VZV were found to differ markedly in their rates of attachment to host cells, with DHV requiring over 6 h of adsorption, while VZV adsorption was essentially complete at 1 h. Also, cell-free DHV was much more resistant than cell-free VZV to repeated cycles of freezing and thawing.

Animals↗