[Inhibitory activity of sera from infected goats on syncitia formation due to caprine arthritis and encephalitis virus (CAEV)].

A very small number of goat positive for caprine arthritis encephalitis virus are also capable of in vitro inhibition of specific tissue culture lesions. This neutralizing activity for apparition of multinucleated cells is present in sera at low dilutions. We found this seric activity under natural conditions in young goats and in culled animals. Under experimental conditions the inhibitory activity was shown in the serum in a goat infected during gestation and in two animals infected when treated with repeated cortisone injection. The presence of syncitia formation inhibitory activity in sera seems to be related with virus reactivation.