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Biomedical subjects

T L Barber

Publications and source records attributed to T L Barber.

At least 37 records · Page 2Linked to original sources
PubMed1979

The nucleic acid and proteins of epizootic haemorrhagic disease virus.

Purified epizootic haemorrhagic disease virus (EHDV) was shown to contain 10 double-stranded RNA segments and a double-layered protein capsid with 4 major and 4 minor polypeptides. The virus differed from bluetongue virus (BTV), the orbivirus prototype, in that EHDV had an additional minor polypeptide component. This component, together with the major polypeptides P2 and P5, formed the outer capsid layer of the virus. The extra polypeptide apparently stabilizes this layer since, unlike BTV, EHDV was quite stable on CsCl gradients at both pH 7,0 and 8,0. EHD virions were found to have a density of 1,36 g/microliter, while particles without the outer capsid layer were isolated and had a density of 1,40 g/microliter. Two non-capsid polypeptides, P5A and P6A, were identified in addition to the 8 capsid polypeptides. Polypeptide P5A was synthesized in excess of all the others. There was little homology between the nucleic acids of EHDV and BTV with only 5-10% cross-hybridization. No hybrid double-stranded RNA segments were identified. We found by cross-immune precipitation that the major core polypeptides of the 2 viruses (P7 and P3) have common antigenic determinants.

Antigens, Viral↗
PubMed1978

Efficacy of trivalent inactivated encephalomyelitis virus vaccine in horses.

Twenty-nine horses were vaccinated with a trivalent (Venezuelan, eastern, and western) inactivated equine encephalomyelitis virus vaccine. The vaccine purchased for this study was the only one licensed and commercially available in May, 1975. Plaque-neutralizing and hemagglutinin-inhibiting antibodies in response to each of the 3 equine encephalomyelitis viruses were determined after vaccination. Horses had rising levels of plaque-neutralizing and hemagglutinin-inhibiting antibodies shortly after injection with the 1st and 2nd doses of the vaccine (given 3 weeks apart) and were refractory to challenge of immunity with virulent homologous virus at 3, 8, and 12 months after vaccination. After 12 months, 8 horses were revaccinated; maximum antigenic stimulation was achieved with the 1st dose of the 2nd series of vaccinations.

Animals↗
PubMed1977

Vitamin E enhancement of Venezuelan equine encephalomyelitis antibody response in guinea pigs.

Immune response potentiation by vitamin E was studied in guinea pigs with Venezuelan equine encephalomyelitis attenuated live-virus vaccine as the antigenic stimulus; antibodies were measured by the hemagglutination-inhibition (HI) test. Significantly higher (P less than 0.01) HI antibody titers resulted when guinea pigs were given intramuscular injections of dl-alpha-tocopherol, 33 IU/kg of body weight, before and after immunization. The HI antibody titers to Venezuelan equine encephalomyelitis virus were not increased when guinea pigs were given dl-alpha-tocopheryl acetate orally. This is the first report on vitamin E humoral immune response enhancement to an attenuated live-virus vaccine.

Animals↗
PubMed1971

Identification of Mycoplasmatales: procedures for both characterization and purification.

Procedures with potential value for identification and purification of Mycoplasma were applied to over 240 cultures representing 11 of the 12 known avian serotypes. Growth was tested at pH 5.5 and 9.5, at 25 and 42 C, in serum-free media, and in the presence of (i) 1% bile salts, (ii) 3% NaCl, and (iii) 0.02% methylene blue. One avian Mycoplasma serotype grew in broth containing 1% bile salts. Two of 11 avian serotypes were resistant to 0.02% methylene blue. A number of Mycoplasma strains grew at 42 C or in a pH 9.5 medium. Usefulness of these procedures for purifying cultures of Mycoplasma is discussed.

Agar↗
PubMed1971

Identification of Mycoplasmatales: characterization procedures.

A large collection of avian Mycoplasma cultures was used in studies to improve and develop biological and biochemical characterization techniques. Differential patterns among 11 avian serotypes were shown by carbohydrate fermentation, tetrazolium- and methylene blue-reduction reactions, breakdown of arginine, and the formation of film on egg yolk-agar. Some cultures fermented as many as 14 carbohydrates. Polyhydric alcohols and pentoses were among the compounds fermented. An improved procedure for determining methylene blue reduction by Mycoplasma was developed. These simple, rapid procedures are reproducible and should be useful in grouping Mycoplasma isolates prior to definitive identification by serological or other means.

Agar↗
PubMed1970

Antibody in cattle experimentally infected with contagious bovine pleuropneumonia.

Antibody responses in cattle experimentally infected with contagious bovine pleuropneumonia were assayed by the complement fixation (CF), plate agglutination (PA), and agar-gel diffusion precipitin (AGDP) tests. Sera were also fractionated by sucrose gradient centrifugation, by chromatography on diethylaminoethyl (DEAE)-cellulose columns, and by starch-block electrophoresis. Serum fractions were assayed for antibody by the CF and PA tests. Antibody was detected by the CF and PA tests from 7 days postinoculation (DPI) throughout the test period of 154 days. The AGDP test was the least sensitive and was negative after 28 DPI. By sucrose gradient centrifugal analysis, only 19S antibody could be detected in the 7 DPI sera, but 19 and 7S antibodies were found in the 14, 21, 28, 35, and 42 DPI sera. Only 7S antibody was found in sera subsequently collected until 154 DPI at the conclusion of the experiment. Results of chromatographic fractionation of sera on DEAE-cellulose columns showed that most of the CF antibody was adsorbed when 0.0175 m phosphate buffer (pH 6.3) was used for elution of proteins. Plate agglutination antibody activity was found in both immunoglobulin (Ig)G and IgM fractions from 7 to 42 DPI and only in the IgG fraction thereafter. By starch-block electrophoresis, the 14 DPI antibody was of beta mobility (IgM), whereas at 21 DPI the antibody mobility was gamma-beta. In the 28 and later DPI sera, CF antibody had gamma mobility.

Journal Article↗