Prion early kinetics revisited using a streptomycin-based PrP(res) extraction method.

The use of streptomycin in the PrP(sc) detection procedures represents a new and attractive way to detect more PrP(sc), the best marker for the transmissible spongiform encephalopathies (TSEs). Actually, the streptomycin PrP(sc) aggregating property reported recently was established as beneficial in PrP(sc) detection using immunohistochemistry in diagnostic as well as in experimental conditions. The present study reports in details how to use advantageously this original streptomycin property in PrP(res) biochemical extraction and detection. Using TSE diagnostic brain material, specificity and increased sensitivity using streptomycin-treated samples were substantiated. Then an early sequential brain and spleen sampling (from 7 to 49 days post-inoculation) from C57Bl/6 mice inoculated intra-cerebrally or intra-peritoneally with C506M3 scrapie strain was analysed using streptomycin versus ultracentrifugation PrP(res) extraction. Whatever the inoculation route, streptomycin allowed earlier PrP(res) detection in spleen (7 d.p.i.), then in brain suggesting a stronger affinity of the infectious agent for the lymphoid compartment.