• All cultures from nine seronegative adult and 12 foetal donors gave rise to cell lines following subculture 4 weeks post infection. (nih.gov)
  • In contrast, seropositive donor cultures seeded at the higher cell concentrations developed foci of proliferating EBNA-positive cells within the first 1--2 weeks but thereafter regressed completely and subcultures made after 4 weeks never gave rise to cell lines. (nih.gov)