Viral RNA Isolation from Macaque Blood

Viral RNA was isolated from macaque blood samples as described previously (20 (link), 38 (link)). Briefly, plasma was isolated from EDTA-anticoagulated whole blood on the day of collection using Ficoll density centrifugation for 30 min at 1,860 × g if the blood was being processed for peripheral blood mononuclear cells (PBMC), or it was centrifuged in the blood tube at 1,400 × g for 15 min. The plasma layer was removed, transferred to a sterile 15-ml conical tube, and spun at 670 × g for an additional 8 min to remove any remaining cells. Viral RNA was extracted from a 300-μl plasma aliquot using the Viral Total Nucleic Acid kit (Promega, Madison, WI) on a Maxwell 16 MDx or Maxwell RSC 48 instrument (Promega, Madison, WI).