An analysis of cellular proliferation, and synthesis of lymphokines and specific antibody in vitro by leucocytes from immunized cattle

The relationships between the production of lymphokines, cellular proliferation and antibody synthesis by immune bovine PBL in vitro was examined to identify the cellular reactions responsible for differences in the titres of serum antibodies in calves from selected sire lines and MHC Class I phenotypes. Leucocytes from 22 calves immunized with ovalbumin and DNP-BSA proliferated specifically in vitro in the presence of 1-10 micrograms/ml ovalbumin 7-28 days after the second vaccination. Significant correlations between the production of IL-2, IFN-gamma and maximum proliferation were observed for the total group. The quantity of specific antibody produced when PBL were incubated alone or with 10(-1)-10(-2) micrograms/ml ovalbumin was also correlated significantly with the maximum proliferation and the serum antibody titre between 7 and 14 days. Anti-ovalbumin IgG was also synthesized in MLRs where the quantity of antibody was significantly correlated with the magnitude of proliferation. The responses in vitro to DNP-BSA were too low to provide meaningful comparisons. The results indicate that at intervals during the period of increasing serum titres, events in the bovine antibody response in vivo can be replicated in vitro. In addition, assays for proliferation, IL-2 or gamma-IFN, or specific antibody can be used to assess the magnitude of the immune response in vivo in experimental groups of cattle. Significant sire line differences in the serological responses to ovalbumin were observed but DNP-BSA was a poorer antigen and differences in the responses to this antigen were not significant. However, the sire line differences in vivo were not reflected in vitro in proliferative and lymphokine assays; only the production of antibody in vitro was significantly correlated with the in vivo serum titre.     

Use of inactivated oil emulsion infectious bursal disease vaccines in breeder chickens to prevent immunosuppression in progeny chicks

Two chicken flocks, vaccinated with different inactivated infectious bursal disease vaccines, and one unvaccinated flock provided chicks with high and low levels of and no maternally derived immunity. Following challenge at three ages with a subclinical strain of infectious bursal disease virus the chicks were assessed for bursal damage and suppression of the immune response to Newcastle disease virus. Both high and low levels of maternally derived antibody prevented immunosuppression but the lower level provided only partial protection against bursal damage.     

The natural occurrence of scrapie in moufflon.

Six cases of scrapie were confirmed in two separately maintained flocks of moufflon, in both of which the disease appeared to be endemic. The clinical signs and histopathology were indistinguishable from those observed in scrapie-affected domesticated sheep. The pathology included lesions in the cerebral cortex which, although commonly present in scrapie-affected sheep, have not previously been described in the natural disease.     

Campylobacter infection in a closed dog breeding colony

Most dogs in a closed breeding unit were shown to be asymptomatic excretors of campylobacter organisms by eight weeks old. Increasing serum antibody levels, which were correlated with the excretion of organisms, were demonstrated in the puppies and serum antibodies were also demonstrated in adult dogs. The significance of these findings with respect to the pathogenicity of campylobacter in dogs and their zoonotic implications are discussed.     

Microbiological and serological studies on caprine pneumonias in Oman

Eight of 10 typical cases of contagious caprine pleuro-pneumonia in Oman yielded strain F38-like mycoplasmas from the lungs in high titre, but no other mycoplasmas: both negative animals had been treated with tylosin shortly before death. Among 21 other lungs examined three of six cases of acute pneumonia yielded Mycoplasma ovipneumoniae; one also yielded M capricolum. M ovipneumoniae was also isolated from all eight cases of chronic pneumonia sampled from an abattoir, and from the lungs of three animals which died without overt signs of pneumonia. A single isolate of M arginini and three of unidentified mycoplasmas were also obtained from goats with and without pneumonia. Various bacterial species were isolated, none of which predominated. Antibodies to M mycoides subspecies capri (M m capri) and strain F38 were detected in sera from eight different sources. Assuming titres of 1 in 40 or more as positive in the indirect haemagglutination test used, 29 per cent of 422 serum samples had antibodies to M m capri alone, 2.6 per cent to strain F38 alone and 3.6 per cent to both organisms. These results confirm the presence of F38-like mycoplasmas in Oman, and indicate also widespread infection with M m capri. The role of the latter in caprine pneumonias in Oman requires elucidation.