Persistent infection with bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) in cultured hamster cells

Destruction of bacterial viruses in serum by heat and radiation under conditions that sustain the ability of serum to support growth of cells in suspended culture

Methods for inactivating bacterial viruses in serum were developed through the use of heat and ionizing radiation, and the effects of these treatments on the growth rates of cultured cells were tested. Viruses chosen for this study were the radiation-resistant bacteriphage f2 and heat-resistant phage T4. The viabilities of these phages were reduced more than 2 and 4 orders of magnitude, respectively, by a treatment at 60 degrees C for 30 min followed by 420 krads of ionizing radiation. Simultaneous application of heat and radiation caused a considerably greater reduction in viability of both phages in serum, but also caused a significant decrease in the growth rates of L cells in medium supplemented with serum treated in this manner. Treatment of serum with these same doses but given in the sequential fashion of heat followed by radiation caused little or no change in the growth rates of L cells. Finally, it was found that simultaneous treatment of serum with these doses of heat and radiation had little effect on the growth rates of either HeLa or Chinese hamster cells.