Relationship of infecting dose to recovery of Rauscher murine leukemia virus (RMLV) in random bred Swiss mice.

Random l>red Swiss mice were infected with graded decimal doses of Rauscher murino leukemia virus via the intravenous or intraperitonea] routes. Samples of spleen and plasma were then collected at various times after infection. Hioassay of these samples in recipient mice revealed a definite relationship between the amount of virus used to initiate the infection and the amount of virus recovered as measured by a spleen focus assay. Highest infective titers were obtained when the most concentrated inocula wore used and the relative titers of virus in the pooled plasmas and spleens decreased as successively less concentrated inocula were used to initiate the infection. Plasma and spleen samples contained more virus when the inocula were injected intravenously than when injected intraperitoneally. In addition, virus was detectable earlier and persisted at higher levels when the initiating virus was injected intravenously rather than intraperitoneally.