Effect of cupric-isonicotinic acid hydrazide complex on normal and avian myeloblastosis virus-infected cells cultivated in vitro.

The cupric complex of isonicotinic acid hydrazide was found to be nontoxic to normal yolk sac macrophages upto a concentration of 100 μΜ. At this concentration the complex did not significantly inhibit DNA, RNA or protein synthesis in these cells. The complex inhibited the avian myeloblastosis virus multiplication in these cells when added 0–4 h post-infection as demonstrated by the inhibition of both focus formation and expression of viral specific antigens. This inhibition was not observed when the complex was added 8 and 16 h after avian myeloblastosis virus infection. The studies carried out on avian myeloblastosis virus-transformed myeloblasts indicated that the complex had no effect on the colony (focus) formation. The results suggest that the complex inhibits the virus multiplication by interfering in an early event of viral growth cycle, possibly the process of reverse transcription.