Chromomycin A3 inhibits influenza a virus multiplication
in chick embryo fibroblast cells.
Conti G, Portincasa P.
Department of Pathology, Medical School, University of Parma, Italy.
The multiplication of Ulster 73 virus, an avian strain of type A influenza
virus, was blocked in chick embryo fibroblast cells, CEF, by treatment with 0.5
microg/ml of chromomycin A3 whereas in LLC-MK2 cells no inhibition of
replication was observed. Virus-induced polypeptide synthesis in chick embryo
fibroblast cells was confined to the synthesis of PB2, PB1 and PA subunits of
the RNA dependent-RNA polymerase, the nucleoprotein NP, the non-structural
protein NS1, the haemagglutinin HA, the non-structural protein NS2; only the
membrane M1 polypeptide synthesis was greatly inhibited. Viral unpolyadenylated
cRNAs synthesis was studied at a late time of the infection, 8 hours p.i.:
chromomycin A3 was able to inhibit the "novo" synthesis of complementary RNA
poly(A)- and segment 7 of virion RNA. The mode of action of the drug in chick
embryo fibroblast cells is discussed.