Preliminary characterization of equine interferons and their antiviral activities on bovine, ovine, and human cells.

Equine dermal cells induced with poly I:C + DEAE-dextran produced low levels of interferon tentatively classified as equine interferon beta (EqIFN-beta). In contrast, dermal cells initially primed with EqIFN-beta and then superinduced with poly I:C + DEAE-dextran in the presence of cycloheximide and actinomycin D produced greater than 100-fold EqIFN-beta. Equine blood mononuclear cells induced with Newcastle disease virus and phytohemagglutinin produced high levels of interferons tentatively classified as equine interferon alpha (EqIFN-alpha) and equine interferon gamma (EqIFN-gamma), respectively. Both EqIFN-beta and EqIFN-gamma exhibited equivalent antiviral activity on equine, bovine, and ovine cells while EqIFN-alpha had greater activity on bovine and ovine cells than on equine cells. Furthermore, EqIFN-alpha had high antiviral activity on human cells. No detectable levels of antiviral activity of equine interferons was observed on feline and mouse cells.