Increased detection and yield of adenovirus in caffeine-stabilised KB cell monolayers

Viable monolayers of KB cells were maintained without passage for up to one year by adding 2 X 10(-3) M caffeine to the medium, while untreated monolayers degenerated after 2 weeks. When adenoviruses type 2 and 17 were titrated on caffeine-stabilised KB cells, the late breakthrough of cytopathic effect at terminal dilutions (up to 40 days after inoculation) resulted in titre determinations up to 100-fold higher than those measured before spontaneous degeneration in untreated cells. Yields of adenovirus type 2 in caffeine-treated KB cultures infected at different multiplicities and harvested at different intervals were equal to, or up to 100-fold higher than those obtained in untreated cultures.