Inhibition Of Influenza Virion Transcriptases By Polynucleotides

Poly(A), poly(I), poly(U), and a thiolated derivative poly(4-thiouridylic acid) inhibit the virion-associated transcriptase of influenza A/Victoria/75 with IDS 50 values of 300, 40, 4, and 1 μg/ml, respectively. A copolymer containing 9% cytidine and 91% 4-thiouridine residues (poly(C,S 4 U 10 )) inhibits the transcriptase to the same extent as poly(4-thiouridylic acid) and the copolymer also inhibits the transcriptase from a range of A strain influenzas, B/Lee/40 and fowl plague virus. Inhibition by poly(U) is dependent on the polymeric nature of the compound: inhibition decreases with oligomers of 20 residues and less. A sugar-phosphate backbone appears to be important for inhibition since vinyl analogs of poly(U) and poly(A) have little or no inhibitory activity.