TABLE 2.

Prion infectivity in brain and spleen samples of IL-10−/− and 129Sv mice inoculated with RML 5.0a

GenotypeInoculum of RMLIntracerebral routePeripheral route
Brain tissueBrain tissueSpleen tissue
Mean incubation time (days) ± SDTiterMean incubation time (days) ± SDTiterMean incubation time (days) ± SDTiter
IL-10−/−10−171 ± 07.080 ± 275.385 ± 54.4
70 ± 17.191 ± 193.397 ± 142.2
10−458 ± 29.465 ± 98.162 ± 38.6
59 ± 29.271 ± 97.061 ± 28.8
129Sv10−162 ± 28.680 ± 15.375 ± 66.2
61 ± 38.881 ± 125.183 ± 64.8
10−464 ± 18.285 ± 34.472 ± 26.8
62 ± 28.687 ± 24.074 ± 46.4
  • a Twenty-microliter volumes of 1% (wt/vol) brain or spleen homogenates prepared from IL-10−/− or 129Sv mice that had succumbed to terminal prion disease were inoculated intracerebrally into tga20 indicator mice. Inoculated mice were monitored daily for clinical signs of mouse prion disease. Mice that succumbed to terminal prion disease were euthanized at the point of neurological disease and dysfunction. Prion titers were calculated according to the formula y = −0.184x + 9.42, where y is the log10 dilution of the stock RML 5.0 infectivity and x is the incubation time (in days) (58). Prion titers are given as log10 LD50 per gram of tissue (n = 5).