Human interferons protect plants from virus infection.

Abstract
Unfractionated human leukocyte interferon, as well as highly purified subspecies of this interferon, and a purified recombinant of human leukocyte interferon produced in bacteria are active in suppressing multiplicability of tobacco mosaic virus [TMV] in tobacco [Nicotiana tabacum cv. Samsun] leaf discs. Human fibroblast interferon exhibits diverse levels of antiviral activity against TMV but becomes as active as human leukocyte interferon upon incubation with glycosidases. The effect of interferon is reversible; normal multiplication of TMV resumes on removal of interferon.