Viral Load Quantification in Mice

Viral loads were determined at the indicated days post-infection (d.p.i.). Mice were bled from the tail vein, anesthetized, and perfused with PBS via the heart before organ removal to liquid nitrogen and storage in −80 °C until further processing. Brain and spleen were processed for titration in 1.5 mL of ice-cold PBS as described previously [25 (link)]. Part of the processed tissue samples was used immediately for RNA extraction while the other part was kept in −80 °C until further processing for viral titration. Samples of VACV-Lister infected mice were tittered on Vero cells (ATCC CCL-81) while VACV-WR, VACV-WRvFire, and VACV-Wyeth were tittered on BS-C-1 cells (ATCC CCL-26).