OPRK1 and infection: Thus, at 96 h after infection of mel Il, mel Ibr and mel Z cell lines, a proportion of remind viable cells composed 16.2%, 3.7% and 9.5% at a MOI of 1.0 and 26.8%, 8.6% and 21.9% at a MOI of 0.1, respectively, relatively to the corresponding cell line infected with UV-inactivated MV at a MOI of 1.0, while for mel Mtp 64.3% and 82.9%, and mel Kor 23.9% and 59.8% viable cells remained at MOI 1.0 and 0.1, respectively (Figure 2).