“…Clone M-3, a melanin-producing cell line derived from the Cloudman $91 melanoma cell line [58], American Type Culture Collection (CCL 53.1), P815 mastocytoma cells, YAC-1 cells, mouse L-cells, and HeLa $3 cells were obtained and propagated as described previously [12,31]. Purified vaccinia virus, strains WR and IHDJ [12,21,31], were employed in the experiments to be described.…”