Abstract
A system is described in which rhinovirus 2 may be grown in suspension cultures of L 132 cells. The virus adsorbed to the cells more efficiently at 33° than at 4°, probably by means of specific trypsin-sensitive lipoprotein receptors on the cells. Virus penetration demonstrated using a potent virus antiserum was temperature-sensitive and rapid at 33°. During single-cycle virus growth at 33° the latent period was about 4 hr and maximum virus yields were obtained about 10 hr after infection. Addition of 30 mM-MgCl2 in the medium enhanced virus release from the cells but did not affect the total virus yield. Highest virus yields were obtained at pH 7.7 and a temperature of 33°. Lower temperatures increased the latent period. At higher temperatures up to 37° the latent period was shorter and the virus titre ceased to increase earlier. At 39° the latent period was longer than at 33° and there was a severe inhibition of virus production. Shift-up and shift-down experiments indicated that the temperature-sensitive event or events at 39° occurred late in the growth cycle.