Studies on the Susceptibility of C57BL.f6 Mice to Rauscher Virus. II. Multiplication of Rauscher Virus in C57BL/6 Cells In Vivo, and In Vitro 1,2

SUMMARY-Multiplication of Rauscher virus in the CS7BL/6 mice in vivo and in vitro was compared to elucidate the mechanisms responsible for the genetic resistance of CS7BL/6 adults to this virus. Cells from 12 spleens of 4-week-old CS7BL/6 mice were cultured individually in T040 flasks, and half of them were infected with Rasucher virus. Three CS7BL/6 spleen cell lines producing Rauscher virus were established from them: R17-4, R17-S, and R17-6. The tissue culture fluids from the three R17 cell lines induced erythroblastosis and lymphoma. The infectivity titer of the virus propagated in CS7BL/6 cells in vitro was almost the same as that of the virus propagated in BALB/c cells in vitro. The maximum dilutions of tissue culture fluids from R17 cell lines able to induce erythroblastosis in weanling SMA and BALB/c mice were always over 10-2 and sometimes as high as 10-3; this figure remained consistent for over 2 years. However, propagation of Rauscher virus in vivo in the CS7BL/6 mice was much lower than that in the BALB/c mice. As a factor that may be related to the differ