Further investigations of equine interferons in vitro.

Following a published procedure, preparations of equine interferon (EqIFN) were prepared. Equine mononuclear leukocytes were induced with equine influenza virus to yield a preparation designated EqIFN-alpha, or with phytohemagglutinin to yield a preparation designated EqIFN-gamma. A preparation designated EqIFN-beta was obtained from equine embryo kidney cells treated with poly(rI):poly(rC) and DEAE Dextran. The pH and heat stability of these preparations were studied, and also their activity on various equine and ovine cells challenged with difference viruses. Unexpectedly, the EqIFN-gamma preparation was found to be stable at pH 2 and to heat at 60 degrees C for 2 h, whereas the EqIFN-beta preparation was labile under these conditions.