Induction of Antiviral Activity In Vivo and In Vitro by Human Placenta Ribonucleic Acid Treated with Nitrous Acid

Induction of antiviral activity and interferon by human placenta ribonucleic acid deaminated with sodium nitrite (NO₂-RNA) was studied in vitro and in vivo. (1) Viral multiplication in diploid cells from human kidney (HK cells) was depressed by pretreatment with NO₂-RNA, but not by pretreatment with the original placenta RNA. (2) NO₂-RNA showed an interferon-inducing activity in rabbits and mice. (3) NO₂-RNA sedimenting in 18 S and 28 S regions showed a higher antiviral activity than that sedimenting in 4 S region.