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R J Chappel

Publications and source records attributed to R J Chappel.

31 records · Page 2Linked to original sources
PubMed1984

The immunoglobulin response of swine following experimental infection with Leptospira interrogans serovar pomona.

The antibody response of pigs following experimental infection with Leptospira interrogans serovar pomona was examined using enzyme immunoassay (EIA) and the microscopic agglutination test (MAT). Leptospires elicited the production of both IgM and IgG classes of antibody, with IgG levels persisting for much longer than IgM. A comparison of MAT and EIA indicated that the detection of specific IgM by EIA was potentially useful in distinguishing between past and recent infection in pigs. Agglutinins were also detected in the urine of infected animals but these antibodies could not be detected by EIA.

Animals↗
PubMed1983

Comparison of radioimmunoassay with the complement fixation test and the indirect haemolysis test in the field diagnosis of bovine brucellosis.

Sera were collected from female cattle in 118 commercial herds being subjected to a programme to eradicate brucellosis by test and slaughter, in an area in which vaccination of heifer calves with Brucella abortus strain 19 was compulsory. Of 4583 sera positive by the Rose Bengal plate test, the brucellosis radioimmunoassay was positive for 1524, the complement fixation test for 1363 and the indirect haemolysis test for 1141. These figures, and supporting evidence from the eradication programme, suggest that the radioimmunoassay may be a useful supplementary test in problem herds.

Animals↗
PubMed1982

A modified radioimmunoassay for antibodies against Brucella abortus.

The radioimmunoassay for brucellosis previously reported from this laboratory was a sensitive and useful method for detecting antibody against Brucella abortus in bovine serum. Changes in the procedure have improved sensitivity, have apparently increased interassay precision, and have made the assay easier to perform.

Animals↗
PubMed1982

The serological response of cattle to vaccines against brucellosis, as measured by the brucellosis radioimmunoassay and other tests.

Serum sample were obtained from 281 heifers vaccinated with Brucella abortus strain 19, and from 50 heifers that had received two injections of killed B. abortus strain 45/20 adjuvant (K45/20A) vaccine. The serological response measured by the brucellosis radioimmunoassay (RIA) was compared with responses measured by other tests. The serological responses of cattle during the first weeks after strain 19 vaccination were found to give little guide to the frequency of persistent reactions. In the case of strain 19, persistent reactions were considered to be those occurring 12 or more months after vaccination. In heifers vaccinated at the recommended age, small numbers of persistent reactions were given by the RIA (four in 374 sera), the complement fixation test using warm fixation (CFTW) (six in 383) and cold fixation (one in 185), the serum agglutination test (two in 222) and the indirect haemolysis test (IHLT) (two in 369). The Rose Bengal plate test gave 74 persistent reactions in 374 sera. Five of the 50 heifers gave particularly prolonged responses to K45/20A vaccine. In these animals the RIA and IHLT remained positive for longer than the CFTW.

Agglutination Tests↗
PubMed1982

A comparison of the results of the brucellosis radioimmunoassay and other serological test in experimentally infected cattle.

The serology of 27 heifers found to be positive to culture after inoculation with Brucella abortus strain 544, was studied. Eighteen heifers had previously been vaccinated with strain 19 or strain 45/20 and nine were unvaccinated. Post-infection serum samples were tested for Brucella antibodies by radioimmunoassay (RIA), complement fixation test (CFT), indirect haemolysis test (IHLT) and Rose Bengal plate test (RBPT). All of the unvaccinated heifers showed strong humoral responses to experimental infection in the RIA, CFT, IHLT and RBPT. The CFT and RBPT became positive sooner after infection than the other tests in the unvaccinated heifers. However, in vaccinated heifers the RIA was the most sensitive test early in infection and the results of the RBPT were variable. Three of the vaccinated heifers showed weak and inconsistent humoral responses and, in these animals, the RIA gave fewer false negative reactions than the other tests.

Animals↗
PubMed1982

A possible role of Cu2+ ions in bovine antibody-antigen interactions.

A preparation of purified bovine IgG1 was found to contain 0.5 moles of Cu2+ ions per mole of protein. Scatchard analysis of the binding of Cu2+ ions to bovine IgG1 indicated the presence of 4 +/- 1 binding sites with an affinity of 2 x 10(5) M-1. Calculations indicate that in bovine plasma, IgG1 will not compete significantly with albumin for Cu2, whereas a proportion of Cu2+ may well be bound to IgG1 in colostrum. Physiological levels of Cu2+ were found to enhance the interaction between IgG1 antibody and Brucella abortus in the presence of albumin. Irrespective of whether IgG1 binds Cu2+ in vivo, it is possible that Cu2+ can influence the results of serological tests.

Animals↗
PubMed1982

The sensitivities of different immunoassays for detecting leptospiral antigen.

The detection of leptospiral antigen in biological fluids is important for the diagnosis of leptospirosis in animals and man. However the sensitivity of dark field microscopy, the usual detection method, is often inadequate. A comparison was made between the sensitivities of several immunological techniques for detecting Leptospira interrogans serovar hardjo. By staphylococcal coagglutination 10(8) leptospires per ml could be detected and by countercurrent immunoelectrophoresis 10(7) per ml. The best sensitivity obtained by enzyme-linked immunosorbent assay was 10(5) leptospires per ml, and by radioimmunoassay 10(4) to 10(5) per ml. Radioimmunoassay offers the prospect of improved diagnosis of leptospirosis through the detection of leptospiral antigen.

Agglutination Tests↗
PubMed1978

Comparison of the results of some serological tests for bovine brucellosis.

A total of 1887 bovine sera positive to the Rose Bengal plate test were subjected to other serological tests for bovine brucellosis: the complement fixation test using warm fixation (CFTW),the serum agglutination test (SAT) and the radioimmunoassay (RIA). The SAT was generally much less sensitive than the CFTW. Many sera, however, gave positive reactions in the SAT but no reaction in the CFTW or the RIA. These SAT reactions were attributed to IgM antibody. Comparison between the results of the CFTW and the RIA led to the conclusion that 200 ng could be used as a minimum diagnostic reaction in the RIA.

Agglutination Tests↗
PubMed1978

The diagnostic efficiency of some serological tests for bovine brucellosis.

Results obtained from 1887 sera using three serological tests for bovine brucellosis were compared with a serological classification of sera described as the 'probable infection status'. Sera showing apparent false positive and apparent false negative reactions were identified, and were subjected to supplementary testing as appropriate. The serum agglutination test (SAT) gave 35% apparent false negative reactions and 5% apparent false positives. The complement fixation test (CFT) gave 12% apparent false negative reactions using warm fixation (CFTW) and at least 5% using cold fixation (CFTC). The routine diagnostic system used in Victoria, in which the CFTW is supplemented by the CFTC and the SAT, gave 9% apparent false negative reactions and 2% apparent false positive reactions. The radioimmunoassay gave 1% or 6% apparent false negative reactions, depending on the minimum diagnostic value used. Atypical reactions in the CFT sometimes caused difficulties in diagnosis.

Agglutination Tests↗
PubMed1977

The effects of IgG2 and of antigen concentration on prozoning in the complement fixation test for bovine brucellosis.

Addition of Brucella-specific IgG2 to solutions of Brucella-specific IgG1 initially induced prozoning and at higher concentrations prevented all reaction in the complement fixation test (CFT) for bovine brucellosis. Some infected cattle may be diagnosed as brucellosis-free due to a high ratio of specific IgG2 to IgG1. Increasing the concentration of antigen in the CFT reduced the tendency to prozone.

Animals↗
PubMed1976

A quantitative comparison of the sensitivity of serological test for bovine brucellosis to different antibody classes.

Brucella-specific antibodies of different immunoglobulin classes were quantitatively evaluated with respect to their efficiency in serological tests for bovine brucellosis. IgM reacted more efficiently than IgG1 and IgG2 in both the Rose Bengal plate test and serum agglutination test. The complement fixation test was found to be slightly more sensitive to IgM than to IgG1 and did not react to IgG2. IgM was, however, partly inactivated when heated at 60 degrees C. in the presence of serum.

Agglutination Tests↗
PubMed1976

Radioimmunoassay for antibodies against Brucella abortus: a new serological test for bovine brucellosis.

A radioimmunoassay (RIA) has been developed to measure antibodies against Brucella abortus in bovine serum and can be used in the diagnosis of bovine brucellosis. The RIA measures the amount of specific antibody of the IgG1 and IgG2 subclasses but is insensitive to IgM, a characteristic which may make it more suitable than the complement fixation test (CFT) or the serum agglutination test for distinguishing infected animals from those which have been vaccinated with Br. abortus strain 19. The RIA is not subject to prozoning or ambiguous reactions, both of which interfere with the interpretation of the CFT.

Agglutination Tests↗