Neutralization of a Cytopathogenic Bovine Orphan Virus in Tissue Culture by Heat Stable Francis Type Inhibitors in Normal Animal Sera

SUMMARY: A heat stable inhibitor present in the serum of normal animals was found to neutralize the infectivity of a cytopathogenic bovine orphan (CBO) virus. Its distribution and some physical, chemical and biological properties were examined. These properties suggest that the inhibitor for the virus infectivity is similar to, but not identical with Francis type inhibitors in normal animal sera.