Marek's Disease Herpesvirus: In Vivo and in vitro Infection of Kidney Cells of Different Genetic Strains of Chickens

Cell culture techniques showed kidney cells from genetically susceptible S-strain chickens exposed to JM-virus to have higher concentrations of Marek's disease (MD) herpesvirus than did those from pen-mates of the relatively resistant C-, K-, and PDRC-strains. There was quantitative correlation between numbers of focal lesions and MD infectivity of cultures. However, factors affecting in vivo infection did not influence in vitro sensitivity. Cultured cells derived from unexposed genetically susceptible or resistant strains of chickens were equally sensitive to MD herpesvirus in vitro. The data provide circumstantial evidence that the cytopathogenic herpesvirus was the etiological agent of MD.