Replication of PARA (Defective SV40)-Adenoviruses in Simian Cells

Abstract

Summary Human adenovirus types 1, 2, 3, 5, 6, 7, 12, 14, 16, and 21 failed to replicate beyond input titres in green monkey kidney (GMK) cells. Co-infection of the monkey cells with papovavirus SV40 stimulated replication of all the adenoviruses tested. Addition of the defective SV40 genome in the PARA particle carried by an adenovirus type 7 population enabled all the adenoviruses to replicate in the GMK cells. Growth kinetics of the adenoviruses in GMK cells co-infected with SV40 were similar to the kinetics of the virus following addition of PARA. A latent period of 16 to 24 hr was followed by an exponential increase in infectious virus between 24 and 48 hr after inoculation. Synthesis of the PARA component closely paralleled that of the adenoviruses. Both the adenoviruses and PARA remained largely cell-associated throughout the growth cycle. During the replication of the transcapsidants, the titre of the adenovirus was always greater than the titre of the PARA component. Ratios were generally in the order of 500 infectious units of adenovirus per infectious unit of PARA. These results differed from those obtained with the parent PARA-adenovirus type 7 population in which the adenovirus to PARA ratio was approximately 3:1.