Vitamin E-enhanced humoral antibody response to Clostridium perfringens type D in sheep.
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Adjuvants, Immunologic↗
Biomedical subjects
L H Lauerman
Publications and source records attributed to L H Lauerman.
Factors associated with virulence of Mycoplasma synoviae.
Virulence mechanisms of six isolates of Mycoplasma synoviae (MS), previously classified as pathogenic (K1968), moderately pathogenic (WVU 1853, K1858, 92D8034, and F10-2AS), and mildly pathogenic (FMT) in chickens, were examined. The most virulent isolate, K1968, had been found to invade systematically and produce lesions following eye-drop inoculation. In the present study, all isolates were evaluated for presence of a possible cytadhesin and for functional attachment to host cells as indicated by hemagglutination and hemadsorption. Three representative isolates, K1968, 92D8034, and FMT, were evaluated for attachment and colonization in cultured chick tracheal rings and tendon cell monolayers by direct transmission electron microscopic examination and by quantitative polymerase chain reaction assay. Ciliostasis was compared in tracheal organ culture. Previously found differences in pathogenicity of these isolates for chickens could not be explained as differences in attachment and were only partially explained by differences in colonization. Pathogenicity of the most virulent isolate of MS was suspected to be multifactorial, involving attachment and colonization of the upper respiratory tract plus additional unidentified factors associated with systemic invasion and lesion production.
Animals↗
Pathogenicity of Mycoplasma synoviae in chicken embryos.
Pathogenicity of Mycoplasma synoviae (MS) was examined in specific-pathogen-free (SPF) white leghorn chicken embryos. Six isolates of MS were inoculated into 7-day embryos via the yolk sac. Isolates were evaluated for gross and microscopic lesions through 19 days' incubation and for embryo lethality through 20 days' incubation. Isolates in decreasing order of lethality, from lowest to highest 50% embryo lethal dose, were WVU 1853, K1968, K1858, FMT, 92D8034, and F10-2AS. Embryo lethality was consistent with lesion incidence and severity. Embryo lethality did not correlate with previous results regarding pathogenicity of these same six isolates in SPF broiler chickens.
Animals↗
Genetic characterization of chicken anemia virus from commercial broiler chickens in Alabama.
Chicken anemia virus (CAV) isolates show extremely limited genetic variability worldwide. We determined the nucleotide sequence of an 823-nucleotide portion of the 2.3-kb CAV genome found in 10 liver and/or spleen specimens of Alabama 29-to-49-day-old commercial broiler chickens exhibiting lymphocyte depletion of the thymus submitted to the state diagnostic laboratory because of problems unrelated to anemia. We determined the nucleotide sequence directly from DNA isolated from tissues, without isolation of virus in culture. This procedure enabled us to characterize CAV that might not have replicated in culture and avoided the potential for changes during passage. Results confirmed the limited genetic variability of CAV. All sequences were identical in 93% of nucleotide positions. The sequences encoded only two distinct VP1 hypervariable regions, and both had been found previously in other CAV isolates. A novel amino acid, glutamine, was found at VP1 position 22 in half the sequences, replacing the histidine residue encoded by most previously characterized CAV genomes. We were able to distinguish among CAV genomes with different codons at VP1 amino acid 22 and different hypervariable regions by restriction endonuclease analysis of polymerase chain reaction products.
Alabama↗
Immunoglobulin G Fc receptors of Mycoplasma synoviae.
The objective of the study was to demonstrate and characterize IgG Fc receptors of Mycoplasma synoviae. Two IgG Fc receptors were recognized with molecular weights (MW) of 80,000 and 90,000 and isoelectric focusing points (pI) of 5.3 and 4.3, respectively. The activity of the IgG Fc receptors was eliminated by exposure to 0.1 unit of protease for 10 minutes. Mild reduction in activity was observed with trypsin between 100 to 1000 units for 10 minutes. The IgG Fc receptors were resistant to exposure to 60 C for 60 minutes and to 100 C for 20 minutes. The M. synoviae IgG Fc receptors were strongly reactive to affinity-purified Fc Fragment of chicken IgG; affinity-purified chicken IgG; and serum IgG of chicken, quail, pigeon, and turkey. A moderate reaction was detected to human affinity-purified IgG, and weak reactions were detected to affinity-purified IgG of cat, cow, dog, goat, guinea pig, horse, and rabbit. No reaction occurred with IgG of duck, goose, mouse, pig or rat.
Animals↗
Monoclonal antibodies that recognize specific antigens of Mycoplasma gallisepticum and M. synoviae.
The polypeptide profiles of the type strains of Mycoplasma gallisepticum (PG 31) and M. synoviae (WVU 1853) resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were compared. Except for a few discrete peptides that were similar, the species varied considerably in peptide profiles. Congruence was observed between the type strains of each species and homologous cloned serotypes. Protein blots of each species were probed with 2 mouse monoclonal antibodies. Monoclonal antibody G 46 was specific for the antigen p 110 (G) in M. gallisepticum, and S 221 was specific for an antigen complex p 45-50 (S) in M. synoviae. The 2 monoclonal antibodies clearly distinguished between all serotypes of M. gallisepticum and M. synoviae that were examined by Western blot transfer. Autoradiographs of 125I-labeled M. gallisepticum and M. synoviae indicated that p 110 (G) and p 45-50 (S) were surface membrane peptides. Indirect immunofluorescence of M. gallisepticum and M. synoviae in Vero cell cultures supported the autoradiographic findings. The p 110 (G) antigen of M. gallisepticum was heat-stable, pronase-sensitive, and resistant to periodate oxidation, suggesting that its chemical composition is protein. In contrast, the p 45-50 antigen complex of M. synoviae appeared as a broad band in protein blots treated with monoclonal antibody S 221, was sensitive to pronase, and responded to Schiff's reagent but was not completely inhibited by periodate oxidation, suggesting that it is a complex of repeating sequences probably composed of glycosylated peptides.
Animals↗
Effect of maternal antibody on timing of initial vaccination of young white leghorn chickens against infectious bursal disease virus.
Maternal antibody titers in white leghorn chicks against infectious bursal disease virus (IBDV) were measured by a computer-assisted, single-serum-dilution, indirect kinetic-based enzyme-linked immunosorbent assay (KELISA) and by a virus-neutralization (VN) test in order to predict the timing of initial vaccination. Day-old white leghorns were from unvaccinated pullets or from pullets vaccinated either four times or twice with IBDV commercial vaccines. The chicks were immunized once via the drinking water with a commercial "intermediate" live IBDV vaccine at 1, 15, or 28 days of age. Effective initial immunization was confirmed by an increase in antibody to IBDV (serologic conversion) that occurred when maternal antibody decreased to 8 and 9 on a log2 scale. This concentration of antibody was detected between 24 and 28 days of age. The computer-assisted IBDV-KELISA increased the sample processing speed for detecting IBDV antibody, and it was as sensitive as the VN test for predicting the timing of initial IBDV vaccination.
Animals↗
Development and application of a polymerase chain reaction assay for Mycoplasma synoviae.
Mycoplasma synoviae (MS) species-specific primers selected from the 16S rRNA sequence were evaluated by polymerase chain reaction (PCR). The MS primers were MS-1 (5'-GAAGCAAAATAGTGATATCA-3') and MS-2 (5'-GTCGTCTCCGAAGTTAACAA-3'). Analysis of cultures of avian mycoplasmas using the MS PCR indicated 100% specificity and sensitivity: 55 individual isolates of MS tested PCR-positive, and 44 isolates of eight other species of avian mycoplasmas tested PCR-negative. The MS PCR will detect 100 colony-forming units of MS. Analysis of 122 flock data sets indicated a sensitivity for the MS PCR test of 82% and a specificity of 100% as determined by comparison with culture, serology (serum plate test, hemagglutination-inhibition, enzyme-linked immunosorbent assay), epizootiology, and history.
Animals↗
Immunoglobulin receptors used in avian Mycoplasma identification.
Among 77 isolates of avian Mycoplasma examined, IgG receptors were demonstrated on six of the nine species represented. Species identified with receptors were: Mycoplasma gallisepticum (two receptors of approximately 84,000 and 75,000 molecular weight [MW]), M. gallinarum (one receptor of approximately 135,000 MW), M. pullorum (one receptor of approximately 130,000 MW), M. gallinaceum (one receptor of approximately 125,000 MW), M. iowae (two receptors of approximately 50,000 and 38,000 MW), and M. synoviae (two receptors of approximately 91,000 and 81,000 MW). The IgG receptors demonstrated in Western blots consistently identified each of the six species. No IgG receptors were detected on M. iners, M. gallopavonis, or M. meleagridis.
Analysis of Variance↗
Avian mycoplasma identification using polymerase chain reaction amplicon and restriction fragment length polymorphism analysis.
A general mycoplasma polymerase chain reaction (PCR) was used to generate amplicon (DNA amplification product) from nine avian mycoplasma species. The PCR amplicons were reacted with 24 restriction enzymes, and the electrophoretic patterns of restriction fragment length polymorphism (RFLP) were evaluated for differences between species of mycoplasms. Four (DraI, MseI, RsaI, Tsp5091) of the 24 restriction enzymes cut the PCR amplicon of all nine mycoplasma species. The nine avian mycoplasma species could be distinctly differentiated using the RFLP analysis of the PCR amplicon.
Animals↗
Evaluation of diagnostic procedures to detect Mycoplasma synoviae in commercial multiplier-breeder farms and commercial hatcheries in Florida.
Sera from 5325 chickens representing 71 commercial poultry flocks were tested for Mycoplasma synoviae (MS) using standard National Poultry Improvement Program (NPIP) testing guidelines. Based on the NPIP guidelines, only sera (N = 195) from flocks that test positive by specific plate agglutination (SPA) were submitted for additional confirmatory tests. Flocks from three multihouse farms were identified as seropositive for MS and confirmed by culture and polymerase chain reaction (PCR). Serum samples (N = 195) from these seropositive flocks were compared by SPA, enzyme-linked immunoassay (ELISA), and hemagglutination-inhibition (HI). Of the 195 sera tested for MS from these flocks, 145 (74%) sera were positive by SPA. Of the 145 SPA-positive sera, the HI test was positive for 127 samples (90.2%), whereas the ELISA was positive for 141 samples (98.6%). This difference between the two tests was significant (P = 0.0006). Significant differences (P = 0.0002) in titer were obtained from paired serum samples that were submitted to three different laboratories for HI analysis. Both the SPA and HI tests failed to detect early infection in newly introduced flocks following depopulation of MS-positive facilities. Both ELISA and PCR detected new infections on these farms. In the MS outbreak described in this study, SPA was not adequate as the sole screening test and HI was not adequate for confirmation of flock infection status. Continued reliance on the same or a similar type of testing could result in missed infections. Confirmation of infection by PCR was preferable to HI and also may be used in place of culture. The findings of this study suggest that ELISA should be considered as a serologic screen in lieu of SPA, screening with SPA may miss MS-infected flocks, and PCR should be considered as a confirmatory test.
Agglutination Tests↗