PBMC Isolation and Serum Collection

Peripheral blood mononuclear cells (PBMCs) were obtained from total blood collected in EDTA directly from the jugular vein and purified by Ficoll cushion (GE Healthcare) purification as described previously (18 (link)). For serum collection, blood samples were taken into Venojet glass tubes, without anticoagulant on days 0 (naive), 7, 21, 28, and 42 (pre-challenge) and days 2, 4, 7, 9, 11, and 14 (post-challenge) and allowed to clot overnight at 4°C. On the next day, serum was obtained by centrifugation at 3,000 rpm for 10 min at 4°C, aliquoted, and stored at −80°C until use.