EFFECT OF 6-AMINONICOTINAMIDE ON CHICK-EMBRYO TISSUE CULTURES INFECTED WITH VACCINIA VIRUS.

Lee, Spencer H. S. (Dalhousie University, Halifax, Nova Scotia). Effect of 6-aminonicotinamide on chick-embryo tissue cultures infected with vaccinia virus. J. Bacteriol. 88:885-892. 1964.-6-Aminonicotinamide (6-AN) was shown to render chick-embryo fibroblast (CEF) tissue cultures refractory to infection with vaccinia virus. Pretreatment of CEF cultures for 8 hr at 36 C with 5 mug/ml of 6-AN prior to addition of vaccinia virus reduced the titer of active virus to about 0.4% of the levels obtained in the untreated controls, when measured by the number of plaque-forming units per milliliter. The addition of 5 mug of 6-AN to CEF cultures before virus infection retarded the progress of vaccinial infection by 8 to 10 hr at 36 C. The inhibitory effect caused by 5 mug/ml of 6-AN could be reversed by the simultaneous addition of 5 to 50 mug/ml of nicotinamide, but not if added at a later time. 6-AN appears to act on the host cell and not on vaccinia virus. For these tests, a simple plaque assay method was devised, by use of a fluid overlay technique with screw-capped tubes (16 by 125 mm) containing CEF cultures.