The sensitivity of an indirect enzyme-linked immunosorbent assay (ELISA) for bovine IgG serum antibody to Pasteurella haemolytica was compared with that of an indirect hemagglutination (IHA) test. Pasteurella haemolytica serotypes were grown in a chemically defined cell culture medium, and soluble antigens released into the growth medium were used in the ELISA and IHA test. An ELISA with serotype-1 antigen consistently detected antibody in sera that were positive by IHA test (correlation, 99%). Sera reacting with serotype-1 ELISA antigens also reacted with ELISA antigens prepared from other serotypes. Although ELISA titers determined by the 2 methods were approximately linear. Titer increases detected in paired serum samples by either test were similar. The ELISA was more sensitive than was the IHA in detecting colostral IgG antibody in serum of newborn calves. The ELISA uses a simple, stable antigen preparation and detects antibody to P haemolytica serotypes that commonly infect cattle.

Seven hybridomas that secreted monoclonal antibodies (MAB) against the peplomer protein and one that secreted MAB against the nucleocapsid protein of Berne virus (proposed family Toroviridae) were isolated. All MAB directed against the peplomer protein neutralized virus infectivity and, with the exception of MAB 6A7, inhibited each other's binding in competition assays. Neutralization of Berne virus infectivity was potentiated when some MAB were used in pairs. The antibodies have been used to localize toroviral proteins in infected cells; use of antipeplomer MAB 6B10 yielded a diffuse intracytoplasmic immunofluorescence, whereas the antinucleocapsid MAB 1F1 detected antigen in the intra- and perinuclear compartments. By use of radioimmune precipitation, protein A of Staphylococcus aureus was found to bind directly to the nucleocapsid polypeptide, without the requirement for specific antibody. Using fluorescein isothiocyanate-conjugated protein A, the intranuclear accumulation of the nucleoprotein of Berne virus was confirmed by results of immunofluorescence.

An ELISA was used to detect IgG, IgM, and complement (C3) on the surface of canine erythrocytes. Erythrocytes were placed in wells of a microtitration plate and incubated with affinity purified, alkaline phosphatase-conjugated anti-canine IgG, IgM, or C3. Results of the ELISA were compared with the direct antiglobulin test (DAT) by preparing standard reference curves from canine blood type A erythrocytes that had been incubated with serial dilutions (1:2 to 1:8,192) of canine anti-A serum. The ELISA detected increased erythrocyte-bound immunoglobulin and complement at two- to fourfold dilutions greater than thoe required for positive results with the DAT. The ELISA required small sample and reagent volumes and detected lower concentrations of immune components than did the DAT.

Effect of raising types and environmental conditions on the infection of Toxoplasma in the swine, the cat and the man were studied in Cheju Island from Sept. 1987 to Aug. 1988. Blood samples were taken from 214 conventionally raised swine in 6 villages and 506 swine raised in swine specialized farms, 122 cats raised under free moving or restrained conditions in 8 locations, 113 butchers, and 210 villagers. Toxoplasma antibody values of the blood sera were determined using the enzymelinked immunosorbent assay (ELISA). The eating type of viscera was also investigated by using questionnaires. When ELISA method was used, the percentage of Toxoplasma infect swine among the conventionally raised and of those raised in swine specialized farms were 60.7 % and 21.3 %, respectively. The respective antibody values (+- SD) were 0.589 (+- 0.310) and 0.385 (+- 0.237) and differed very significantly (p<0.01). A significant difference was also found in antibody values among 6 villages (p<0.05). The mean infection percentage of Toxoplasma in the cat was 38.2 %, the infection percentage for cats raised under free-moving and restrained condition were 37.0 % and 38.2 % respectively. The respective antibody values (+- SD) for Toxoplasma were 0.600 (+- 0.614) and 0.637 (0.645), and did not differ significantly. The infection percentage of Toxoplasma in villagers and butchers were 26.2 and 38.3 % respectively. The respective antibody values (SD) for toxoplasma were 0.429 (+- 0.195) and 0.341 (+- 0.236), and differed very significantly (p<0.01). There were also highly significant differences Pyo-sun and other village (p<0.01). Analysis of the questionnaires showed that 26.0 % of 392 villages ate liver and some villagers ate other viscera.

Critical parameters affecting sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to avain infections bronchitis virus (IBV) were standardied. By adopting the optimized conditions an equation calculating ELISA antibody titers from the observations at single serum dilution was formulated. The purified antigen of IBV lMass-41 strain was dispensed into polystyrene microplate wells at a concentration of 300ng per well (100 micr l) and the plates were coated by completey drying at 37deg C. Diluted chicken serum and horseradish peroxidase conjugated goat anti-chicken IgG were added in order in 100 micro l volumes per well and allowed to react for 30 minutes each at room temperature. Just before use and after each reaction the plates were washed three times with distilled water. Finally o-phenylenediamine solution was added as an enzyme substrate. After incubation for another 15 minutes at room temperature absorbances were read at 492 nm. Hyperimmune serum against Mass-41 strain was used as internal reference positive (IRP)serum. After repeated titration of IRP and negative sera, a constant titer of IRP was determined. Serum titrations were carried out for various sample sera together with IRP and negative sera and the observed titers of sample sera were corrected by reflecting the ratio between observed and constant titers of IRP serum. These corrected titers of the sample sera were plotted against sample/positive (S/P)OD ratios. All the OD's measured in the serum titrations were also corrected by substracting negative serum OD. The following equation was formulated from the above data; Log10 ELISA titer = 5.568 (log10 S/P) + 4.161. Thus it was possible to calculate ELISA titer by measuring absorbance at 1/400 single serum dilution. Titer measured by cross ELISA tests employing Mass-41 strain and three local IBV isolates were similar. These results suggest that the ELISA tests standardized in this study can be used for evaluating not only vaccinal immunity but also for infection status against fields IBV's

This study was undertaken to establish reliable diagnostic-procedures for the microbiological monitoring of laboratory animals. Murine (mice and rats) antibodies against hemagglutinating virus of Japan (HVJ), mouse hepatitis virus (MHV) and Mycoplasma pulmonis (Mp) were detected sensitively and specifically in experimentally and naturally infected animals' sera by an indirect enzyme-linked immuno-sorbent assay (ELISA), using urease conjugated antimurine immunoglobulin. The sensitivity and specificity of the complement fixation test which has been apllied widely for serodiagnosis of HVJ, MHV and Mp infections were apparently lower than those of ELISA. From these results, the ELISA was found to be available for the serodiagnosis of HVJ, MHV and Mp infections in mice and rats