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Biomedical subjects

M J Corbel

Publications and source records attributed to M J Corbel.

At least 109 records · Page 6Linked to original sources
PubMed1979

The relationship between the protective and cross-reacting antigens of Brucella spp., Yersinia enterocolitica 0:9 and Salmonella serotypes of Kauffmann-White group N.

Vaccination with killed cells of Brucella abortus, Yersinia enterocolitica 0:9 and Salmonella neusdorf evoked cross-reacting antibodies in guinea pigs but only the homologous antigen effectively produced protective immunity to Br. abortus. None of these preparations induced protective immunity to Y. enterocolitica in gerbils but all stimulated protective immunity to S. landau in Balb/c mice. The antigenic determinants responsible for protective immunity to salmonella infection were located on the cross-reacting lipopolysaccharide-peptide agglutinogens of the brucella, yersinia and salmonella organisms. The protective effect could be passively transferred by serum and was probably mediated by IgM antibodies.

Agglutination Tests↗
PubMed1978

Examination of the immunoglobulin classes involved in the serological response of pregnant sheep to Aspergillus fumigatus.

Pregnant sheep inoculated with Aspergillus fumigatus conidia developed agglutinating and precipitating antibodies for mycelial antigens. The agglutinins were initially exclusively of the IgM class, but were later supplemented by IgG antibodies, although IgM production was usually sustained throughout the serological response. Precipitins active in the immunodiffusion test were of the IgG class. They developed later in the immune response than agglutinins and declined more rapidly. The precipitins and IgG agglutinins were more closely associated with recent active infection than IgM agglutinins.

Animals↗
PubMed1978

Observations on the localization of Absidia corymbifera in vivo.

The role of spore distribution and the presence of tissue-specific fungal growth stimulants and inhibitors in determining the in vivo localization of Absidia corymbifera were examined in experimentally infected mice. Intravenous inoculation resulted in generalized distribution of spores, with the highest concentrations accumulating in the liver and spleen. Active lesions containing developing mycelium were confined to the brain, kidneys and occasionally the myocardium. Fungal growth stimulating activity was present in all tissue examined, the liver and spleen being the most active. However at concentrations approaching those of whole tissues, the stimulatory activity of liver and spleen extracts drastically declined whereas that of brain and kidney preparations continued to increase. These effects, in conjunction with local variations in immune processes, were probably responsible for determining the distribution of A. corymbifera mycelial development in vivo.

Animals↗
PubMed1977

Experimental mucormycosis in congenitally athymic (nude) mice.

Athymic nude (nu/nu) mice and their phenotypically normal (nu/+) littermates displayed a similar susceptibility to acute lethal infection with Absidia corymbifera. Although the clinical manifestations of acute infection were also similar in both groups, the nude mice tended to develop more extensive lesions and were less effective in eliminating viable A. corymbifera spores than their heterozygous littermates. The results suggested that thymus-dependent processes did not play an essential role in primary resistance to mucormycosis.

Animals↗
PubMed1977

Cerebral mucormycosis following experimental inoculation with Mortierella wolfii.

A strain of Mortierella wolfii isolated from a case of bovine mycotic abortion in the United Kingdom did not produce disease in mice when inoculated by the intraperitoneal, intramuscular, intravenous or subcutaneous routes. When injected by the intracerebral route, it induced a chronic granulomatous infection of the brain resulting in hydrocephalus and eventually death.

Animals↗
PubMed1977

Examination of the effect of age and acquired immunity on the susceptibility of mice to infection with Aspergillus fumigatus.

Adult CBA mice showed considerably greater resistance to experimental infection with Aspergillus fumigatus than young animals of the same strain (P less than 0.01). Furthermore, in contrast with the young mice, the susceptibility of the adults was only moderately increased by treatment with cortico-steroids. On the other hand, immunosuppressive treatments producing severe depression of lymphocyte function greatly increased susceptibility to lethal infection and promoted fungal growth in a wide range of tissues. These observations suggested a role for specific acquired immunity in the relatively high resistance to experimental aspergillosis shown by older mice.

Age Factors↗
PubMed1976

Experimental phycomycosis in mice; examination of the role of acquired immunity in resistance to Absidia ramosa.

Attempts were made to stimulate acquired immunity to experimental Absidia ramosa infection in mice. Unprotected animals inoculated with large doses of A. ramosa spores frequently developed acute phycomycosis of the central nervous system. Mice previously exposed to sub-lethal doses of spores showed a high resistance to subsequent challenge with A. ramosa. No consistent increase in resistance was observed in mice vaccinated with killed A. ramosa spores, hyphal walls, intracellular mycelial antigens or various combinations of these, with Freund's incomplete adjuvant. Antibodies to soluble mycelial antigens were inconsistently present in the sera of mice vaccinated with sub-lethal doses of viable spores. They were generally present in the sera of animals vaccinated with mycelial extracts of hyphal walls but not killed spores. Delayed hypersensitivity reactions to A. ramosa mycelial antigens could usually be elicited by intradermal tests in mice exposed to viable spores but irregularly in those vaccinated with non-viable preparations. Positive reactions were also frequently given by older mice not deliberately exposed to A. ramosa. Although mice previously exposed to viable A. ramosa spores were highly resistant to intravenous or intracerebral challenge with this fungus, they were more likely to develop persistent local granulomata on subcutaneous injection of spores than were unvaccinated animals.

Animals↗
PubMed1976

The immunogenic activity of ribosomal fractions derived from Brucella abortus.

The immunizing activity of ribosome preparations derived from Brucella abortus strain 19 cells was examined in guinea-pigs and mice. After subcutaneous injections of Br. abortus ribosomes in Freund's incomplete adjuvant, both mice and guinea-pigs developed immunity to challenge by virulent Br. abortus 544 organisms which was at least as effective as the protection conferred by live strain 19 vaccine. Both mice and guinea-pigs also developed agglutinating and complement-fixing antibodies and delayed hypersensitivity to Br. Abortus antigens. Conversely, ribosome preparations elicited delayed hypersensitivity reactions on intracutaneous injection into guinea-pigs chronically infected with Br. abortus or Br. melitensis. On injection into rabbits, Br. abortus ribosomes incorporated in incomplete adjuvant induced high titres of agglutinins, complement fxing antibodies and precipitins for Br. abortus antigens. On immunochemical examination, the ribosome preparations were not grossly contaminated with antigens derived from the cell surface. They were chemically complex, however, and in addition to RNA contained numerous protein components identified by disk electrophoresis. The nature of the components responsible for conferring protection against Br. abortus was not determined.

Agglutinins↗
PubMed1976

The relative susceptibility of New Zealand black and CBA mice to infection with opportunistic fungal pathogens.

The susceptibility of ageing New Zealand Black (NZB) mice to infection with a number of opportunistic fungi and yeasts wsd compared with that of similarly aged mice of the CBA strain. The NZB mice showed a greater susceptibility to lethal infection with Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans than did those of the CBA strain. Both mouse strains showed similar susceptibility to lethal infection by Allescheria boydii, Absidia corymbifera, Mucor pusillus and Rhizopus oryzae. The clinical and histopathological characteristics of the infections produced by Allesch boydii, Asp. fumigatus, Abs. corymbifera, M. pusillus and R. oryzae were similar for both mouse strains. In contrast C. albicans and Crypto. neoformans produced much more severe infections in NZB mice than in CBA mice. These results suggested that T-lymphocyte dependent immune processes played a major role in resistance to C. albicans and Crypto. neoformans but not to Abs. corymbifera, Allesch. boydii, Asp. fumigatus, M. pusillus or R. oryzae.

Animals↗
PubMed1976

Recommendations for the description of species and biotypes of the genus Brucella.

The properties of the genus Brucella are summarized and recommendations made for the definition of species and biotypes within the genus. In the first instance it is recommended that the classification of an organism as a member of the genus should be based on the following criteria: gramnegative coccobacillary morphology, a G + C content for the DNA of 56-58 moles %, a minimum of 90% homology with the DNA of reference strains in hybridization tests, disk electrophoretograms of acid-phenol soluble proteins of identical pattern to reference strains, a cytochrome C absorption spectrum with absorption maxima between 522-530 nm and 552-560 nm, extensive serological cross-reactions of intra-cellular antigens with those of reference strains. Supporting evidence is obtained from cultural, biochemical and pathogenic properties, although variations in these occur within the genus. Subdivision into species is dependent upon principal natural host, oxidative metabolic pattern and phage sensitivity. Classification into biotypes is dependent upon CO2 requirement, H2S production, dye sensitivity and reaction with monospecific antisera to A and M antigens. It is recommended that any organism proposed as a new member of the genus should have characters which approximate the ranges quoted. In all cases comparisons should be made with the established reference/neotype strains.

Antigens, Bacterial↗
PubMed1976

Properties of some new Brucella phage isolates; evidence for lysogeny within the genus.

A number of phages were isolated from Brucella abortus strains showing atypical phage sensitivity patterns. The phages, designated the Firenze group, were all similar in morphology, host range general properties. They were lytic for smooth Brucella abortus, Br. neotomae and Br. suis, but not for Br. melitensis strains. They were serologically distinct from phages of the Tbilisi and M51-S708-Weybridge groups and also differed from these in plaque morphology and physical and chemical stability. The parent brucella strains although smooth were resistant to lysis by their own phages or by the other available brucella phages. Their general properties suggested a lysogenic state.

Antigens, Viral↗
PubMed1976

The immunological properties of Brucella ribosomal preparations.

Ribosomes were isolated from Brucella abortus strains 19 and 45/20 by disruption of the cells followed by differential ultracentrifugation. The ribosome preparations contained 2-3 components reacting in immunodiffusion tests but were free of detectable lipopolysaccharide-protein agglutinogen. They crossreacted with antisera to Br. abortus, Br. melitensis, Br. suis and Br. ovis and elicited intradermal delayed hypersensitivity reactions in animals infected with Br. abortus, Br. melitensis or Br. suis. The ribosomes were antigenic in rabbits, guinea pigs and mice. Those from Br. abortus S19 induced agglutinins reaction with smooth brucella strains whereas those from Br. abortus 45/20 induced agglutinins reacting with rough brucella strains. Cattle vaccinated with S19 or 45/20 vaccines or infected with Br. abortus developed pricipitins to ribosomal components at an early stage in the immune response.

Animals↗
PubMed1976

The immune response to Brucella abortus 45/20 adjuvant vaccine in terms of immunoglobin class.

Cattle vaccinated with Brucella abortus 45/20 adjuvant vaccine developed agglutinins for rough brucella antigens which were largely of the IgG classes. Only small amounts of IgM rough agglutinins were produced at the earliest stages of the serological response. Non-agglutinating antibodies detectable in the antiglobulin test were mainly of IgG2 and IgGI classes. Cattle previously exposed to smooth brucella antigens, after vaccination with 45/20 adjuvant vaccine, initially developed high titres of IgM agglutinins reacting with smooth brucella antigens. Subsequently the agglutinins were largely of IgG type. The non-agglutinating antibodies reacting with both smooth and rough antigens were largely of the IgG2 and IgGI sub-classes.

Animals↗
PubMed1976

The serological response to rough and smooth brucella antigens in cattle vaccinated with Brucella abortus strain 45/20 adjuvant vaccine.

Cattle not previously exposed to Brucella abortus responded to a single dose of Br. abortus 45/20 adjuvant vaccine by producing low titres of agglutinins for rough brucella antigens and little or no agglutinins to the smooth antigens. Moderate titres of non-agglutinating antibodies reacting with both rough and smooth antigens were also produced. After a second dose of 45/20 vaccine higher titres of rough agglutinins and low titres of antibodies reacting with smooth antigens were produced. High titres of non-agglutinating antibodies reacting with both rough and smooth antigens were also produced. Animals previously exposed to smooth Br. abortus, either as strain 19 vaccine or virulent organisms, produced high titres of antibodies to smooth antigens soon after vaccination with 45/20 adjuvant vaccine. High titres of antibodies reacting with rough and smooth antigens were also produced. The evidence suggests that the Br. abortus strain 45/20 shares a surface antigenic component with smooth brucellae. The possible relationship of this to the protective antigen is discussed.

Animals↗
PubMed1975

Factors determining the susceptibility of mice to experimental phycomycosis.

Various factors influencing the susceptibility of C3H mice to lethal infection by the phycomycete Absidia ramosa were examined. Mice 19-21 days old were exposed to graded doses of A. ramosa spores by various routes. After intravenous inoculation with doses in excess of 10(3) viable units, a variable proportion of mice developed lethal phycomycosis of the central nervous system within 2-8 days. The proportion of mice affected was related to the inoculum size, doses of 5 X 10(7) spores producing lethal infection in 90-100% of the mice. The disease was characterised by signs of involvement of the central nervous system appearing 8-12 h before death. At necropsy, fungal hyphae, frequently surrounded by infiltrations of mononuclear cells, could be demonstrated in the brain. Lesions were also often present in the kidneys; in other organs they were rare, but the presence of viable fungal spores could be detected by cultural procedures. Subcutaneous inoculation of A. ramosa spores did not produce lethal infection but intraperitoneal inoculation occasionally did so. Direct intracerebral inoculation invariably produced lethal infection even with very small doses of spores. The clinical and histopathological features of the disease were almost identical with those resulting from intravenous inoculation. Pre-inoculation treatment with azathioprine, cyclophosphamide and antithymocyte serum did not increase susceptibility. Susceptibility was increased by injections of zymosan, aggregared gamma-globulin, cortisone acetate and Fe(II) salts and by reticuloendothelial blockade. These treatments increased the proportion of mice developing lethal phycomycosis of the central nervous system, and in the case of cortisone acetate, also promoted disseminated infection. It was concluded that the natural resistance of mice to A. ramosa infection was probably dependent upon the activity of phagocytic cells, possibly acting in conjunction with complement and other non-specific serum factors.

Age Factors↗