NECTIN4 and infection: To determine whether the proliferating and differentiated keratinocytes were susceptible to MV infection, we inoculated them with rMVKSVenus(3) or a strain engineered to be unable to recognize nectin-4 (the ‘nectin-4-blind (N4b)’ strain rMVKS-N4bEGFP(3)) [11] at a multiplicity of infection (MOI) of 1.