The relationship of Brucella abortus agglutinogenic antigens to the receptor sites for Tbilisi phage.
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Biomedical subjects
Publications and source records attributed to M J Corbel.
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Preparations of influenza virus A0 PR8/34 and A2 Malaysia/68 have been studied in the electron microscope. They were similar in appearance to preparations made by others. Each preparation was degraded by Triton N 101. The process of degradation appeared to be different from that observed using ether and, by inference, a number of other agents.
Highly purified influenza virus was degraded using anionic and non-ionic detergents. Best results were obtained using the non-ionic detergent Triton N 101. Tests showed that virus extracts contained neuraminidase and a substance that reacted specifically with rabbit antibody to virus haemagglutinin (specific serum blocking substance). Haemagglutination-inhibiting antibody was produced when virus extracts were inoculated into guinea-pigs. Immunodiffusion tests showed that extracts were complex. Host-specific material was regularly found. Under appropriate conditions S-antigen was detected as a single line pattern component. Two or more virus-specific materials were also present. One of these was probably neuraminidase and the other the specific serum blocking substance.
The serological responses of cattle to inoculation with Brucella abortus and Yersinia enterocolitica type IX were compared. Complete cross-reactions were found in serum agglutination, antiglobulin, complement fixation and Rose Bengal plate tests. The cross-reaction between Br. abortus and Y. enterocolitica IX was confirmed by immunodiffusion tests. Although antibodies specific for each organism could also be detected by immunodiffusion tests with high titre rabbit or bovine sera, these tests were insufficiently sensitive for routine diagnostic use.A quantitative Rose Bengal plate test, using Rose Bengal stained Br. abortus and Y. enterocolitica IX, was developed which enabled the antibody responses to the two organisms to be differentiated. The specificity of this test was confirmed by cross-absorption experiments and its sensitivity was sufficient to permit evaluation of all bovine sera giving positive reactions to the serum agglutination test.
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Thirty cows presenting with lameness and persistent serological reactions to Brucella abortus had chronic granulomatous arthropathy of the femorotibial and occasionally other joints. Attempts to culture Brucella or other pathogens gave negative results but organisms of Brucella morphology were seen in fluorescent antibody-stained cryostat sections of synovial tissue. The synovial fluids contained high titres of antibodies to B. abortus and Yersinia enterocolitica O:9 and had elevated total protein and immunoglobulin concentrations showing an oligoclonal electrophoretic profile. Immune complexes and rheumatoid factor were detected in some of the fluids.
Attempts to reproduce in calves the arthropathy associated with Brucella abortus strain 19 (S19) vaccination by direct intra-articular injection of S19 or virulent Brucella cells were unsuccessful. Intra-articular injection of rabbits and a calf with immune complexes isolated from the synovial fluid of a field case produced clinical and histological signs of arthropathy accompanied by the development of rheumatoid factor.
Of five pregnant cows inoculated intravenously with 5 X 10(8) viable 'Haemophilus somnus', one aborted within 5 days and excreted 'H. somnus' from the vagina for a further 7 weeks. A second cow proceeded to full term parturition but both it and its apparently healthy calf persistently excreted 'H. somnus'. The other animals underwent normal full term calvings and 'H. somnus' was not isolated from them or their calves. Lesions attributable to 'H. somnus' were detected only in the aborted fetus which showed an acute generalized inflammatory cell response consistent with a systemic Gram-negative bacterial infection. 'H. somnus' was isolated from all fetal tissues, including the placenta. The fetus and placenta also showed evidence of damage prior to inoculation. The placental damage may have predisposed the fetus and placenta to infection with 'H. somnus'. The placental epithelial cells contained intracytoplasmic organisms with the morphological and antigenic properties of 'H. somnus'.
Four strains of Mortierella wolfii isolated from cattle in Britain were compared in pathogenicity and toxigenicity with a strain isolated from a cow with the mycotic abortion-pneumonia syndrome in New Zealand. All strains produced acute lethal infection in rabbits after intravenous inoculation of mycelial suspensions and all produced subacute mycotic encephalitis in mice after intracerebral injection. They also produced an acid-stable, heat- and trypsin-labile toxin in vitro. The action of the toxin was exerted mainly on the kidneys in rabbits and mice and produced effects distinct from those resulting from infection with M. wolfii.
A strain of Yersinia enterocolitica of O serogroup 6,30 isolated from the liver of an aborted ovine fetus was inoculated intravenously into a group of pregnant ewes at about 90 days gestation and produced placentitis with abortion or delivery of infected lambs about 50 days later. Y. enterocolitica of the same serogroup was recovered from the necrotic placental cotyledons and most other fetal tissues and could be isolated from vaginal discharges of the ewes for a least 2 weeks after abortion. Histological changes were consistent with an acute bacterial necrotizing placentitis and systemic infection of the fetus. Subsequent pregnancies in the ewes proceeded to term without evidence of infection.
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