Effect of heparin on infection of cells by equine arteritis virus

The number of plaques formed by equine arteritis virus (EAV) and Aujesky's disease virus (ADV) was reduced to 14% and 5% of the untreated control (100%), respectively, by 10 U/ml of heparin, but could not be reduced below to 13 and 4%, respectively, by use of concentration up to 100 U/ml. An inhibitory effect of heparin, at concentration up to 100 U/ml, was not observed on parainfluenza virus 3 (PIV-3). Heparinase treatment of RK13 cells reduced the number of EAV-, as well as ADV-induced plaques. On the other hand, the number of PIV-3 induced plaques did not decrease after treatment of RK13 cells with heparinase.