STUDIES ON POLIOVIRUS INHIBITORS IN SERA OF DOMESTIC ANIMALS: I. DISTRIBUTIONS AND PROPERTIES OF POLIOVIRUS INHIBITORS IN BOVINE AND EQUINE SERA

A study was made on the distribution and properties of poliovirus inhibitors in equine and bovine sera. The inhibitors were readily detectable at a high frequency in bovine serum, independently of the method of examination. In contrast to this, the detection of inhibitors in equine serum was affected greatly by the method employed. Inhibitors active to particular couples of the same type viruses were found in equine as well as in bovine sera. The activity of inhibitors against poliovirus differed with its antigenic types, suggesting that the inhibitors may differ qualitatively. A bovine serum similar to a certain equine serum in the activity to the same group of type 1 viruses was found. Differentiation of poliovirus strains by comparing their sensitivities to inhibitors was possible with some limitations. The inhibitors developed in sera of both species of animals, at the ages of between 6 and 12 months, increased with the age up to 2 years, but its annual increase at higher age levels was irregular.