Methods for the detection of viruses in bovine serum

Abstract

An evaluation of selected commonly used procedures for the recovery of endogenous viral contaminants in bovine serum was undertaken. Low speed centrifugation (25,000 x g) was found to be efficient for the recovery of bovine herpesvirus type 1 (BHV-1) and parainfluenza virus type 3 (PI-3) in bovine serum. Decreased infectivity titers were obtained when parainfluenza virus type 3, and to a lesser extent bovine herpesvirus type 1, were concentrated using high speed centrifugation (100,000 x g) for extended time periods. In neither case could infectious virus be recovered from serum containing sufficient titers of homologous neutralizing antibody, although electron microscopy examination revealed the presence of the viruses previously added. In the presence of homologous antibody, virus particles appeared to have a diffuse, poorly defined outer membrane. Neutralizing antibody titers to bovine herpesvirus type 1 and parainfluenza virus types were found in fetal, calf, and adult bovine sera. The prevalence and magnitude of the antibody titers to these viruses increased with the age of the animals examined.

Elimination of bacteriophages from tissue culture serum by affinity chromatography

“…Bioselective adsorption on inert matrices has proved to be useful in separating various classes of biological substances (4,5,8,16,18). Although the present study as a model system applied the principle of biospecific adsorption by immobilized antibodies for removal of a specific bacteriophage, the technique should lend itself as well for the selective removal of other microbial agents such as mammalian viruses and mycoplasmas that have been found in tissue culture serum (2,6,11,17). Because the adsorption reaction was highly specific, it is unlikely that affinity chromatography, per se, would afford a practical means to eliminate all the different types of undersirable agents that may be present in contaminated tissue culture…”

Mysteries and miracles

“…After 1 week of examination, according to Dr. Fong's EM result, virus particles of a paramyxovirus and also herpes particle were found in the calf serum sample. However, to my great surprise, only the herpes virus induced CPE was noted in the bovine kidney cell culture tubes inoculated with the known mixtures of calf serum samples, but the parainfluenza type 3 virus was never recovered by the second investigator, Dr. Swack (Swack et al, 1975). It was then realized that the lot of calf serum used contained a high titer antibody to parainfluenza virus type 3, thus preventing its recovery in the cell culture method, although the virus particles can be recognized under electron microscopic examination.…”

Use of electron microscopy for detection of viral and other microbial contaminants in bovine sera

“…3, isolation of this virus from bovine sera is usually difficult, as indicated in the accompanying paper (14). In this case, recognition of the presence of virus was accomplished only by morphological observation.…”