Lytic infection of primary rhesus kidney cells by simian virus 40

In an attempt to analyze the persistent infection of rhesus monkey cells with Simian virus 40 (SV40) in vitro, as described previously (reviewed in L. C. Norkin, Microbiol. Rev. 46, 384-425, 1982), we infected primary rhesus cell cultures (PRK), derived from a SV40-free monkey colony with SV40. Surprisingly, SV40 infected PRK cell cultures released as much infectious virus as cultures of the permissive African green monkey kidney cell line TC7. Infected PRK cells exhibited typical symptoms of a lytic infection, and the bulk of infected PRK cells died within 8 days postinfection (p.i.). A considerable proportion of infected PRK cells exhibited distinct SV40-caused cytopathic effects (CPE), similar to CPE in infected TC7 cells. We conclude that the in vivo persistence of SV40 in rhesus monkeys is not determined by cellular host factors, but by the immune system of the infected animals.