A drill with a small burr attachment was used to introduce a 1 mm hole into the skull to allow entry for a Hamilton syringe (5 µL) to inject this website the test article, either IgG1 N434A or IgG1 H435A into the brain (antibodies were dosed in pH-neutral buffers (pH 7.4), unless otherwise stated). For unilateral administration a 1.2 µL bolus of test article (2.0 µg/µL) was administered at a rate of 0.4 µL/min (total

dose=2.4 µg, or 14 µmol/L). For bilateral administration the volume administered to each side was halved (0.6 µL); therefore, the total dose administered was equal to the unilateral administration. Care was taken to perform the surgical procedure following aseptic techniques and a surgical plane of anesthesia was maintained throughout the entire procedure. The incisions of animals were closed and the animals were allowed to recover from anesthesia following the 5 min baseline blood draw.

Animals were given isoflurane to facilitate retro-orbital blood draws of approx 100 µL. All blood samples were allowed to stand for at least 30 min, but no longer than 1 h, centrifuged at 3500 rpm for 15 min and the serum separated and stored at −80 °C. Following the final blood collection a full body perfusion was performed to remove residual blood from the brain via cardiac puncture using 60 mL (15 mL/min, syringe pump) of a PBS solution containing protease inhibitors (1 tablet/10 mL, Complete Mini, Roche, Indianapolis, IN, USA) and 5 mM EDTA. Following Panobinostat cell line perfusion, the anterior cervical lymph nodes were removed and placed in FastPrep tubes. The head was then decapitated and the brain removed and halved into

two hemispheres (excluding the olfactory bulbs), brainstem (hypothalamus to level of cistern magna of hindbrain), and cerebellum. The olfactory epitheliums were collected following intranasal-to-CNS administration only. Brain tissues were placed into pre-weighed lysis Matrix D tubes (MP Biomedical, Cat# 6913-500) or IKA tubes (IKA Cat# 3703100) then re-weighed and quickly frozen on dry ice and stored at −80 °C until homogenization. Brain Digestive enzyme hemispheres were homogenized in 1:10 homogenization buffer (assume 1 g of tissue is 1 mL volume) (TBS 25 mM Tris [pH 7.8], 150 mM NaCl, 1% Triton X-100, 5 mM EDTA and cOmplete, EDTA-free Protease Inhibitor Cocktail Tablets [1 tablet/10 mL]). The brain hemispheres were thawed and homogenized in buffer solution using an IKA instrument (Ultra Turrax, IKA Cat# 3645001) (setting# 6, 20 s). The left and right olfactory epithelia were diluted in the same homogenization buffer, and homogenized using the Bio101 FastPrep instrument (6.5 m/s; 40 s). Full length IgG in the brain and tissue samples was quantified within 24 h of homogenization. Full-length IgG antibodies were quantified using the Meso Scale Discovery (MSD) electrochemiluminescent assay. The mAbs used in this study were a recombinant chimeric human IgG1 monoclonal antibody specific for human respiratory syncytial virus (RSV).