1984 Volume 37 Issue 11 Pages 725-729
Sixty-six serum samples from field cattle (field sera) and 17 samples of commercially available sera (calf and fetal bovine sera) for cell cultures were tested for inhibitory effect on the growth of infectious bursal disease virus (IBDV) by plaque assay. The average plaque reduction due to the field and calf sera was more than 90%, whereas that of the fetal bovine sera was less than 29%.
The serum with high inhibitory effect did not react with IBDV antigen in the immunodiffusion test. This suggested that the effect might not be due to specific antibodies against IBDV.
When the serum with inhibitory effect was fractionated by DEAE-cellulose column chromatography, it was found that the inhibitory effect was mainly associated with the IgG fraction, and relatively low in other pooled fractions. The activity was destroyed by treatment with either trypsin or ethyl ether but not with kaolin, acetone, heparin or receptor-destroying enzyme.
The fluorescent antibody test showed that the serum with high inhibitory effect was attached nonspecifically to chicken embryo fibroblasts.
