Pref alum

Balb/c female mice were purchased from The Jackson Laboratory (Bar Harbor, ME). The sero+ females were purchased at 4 weeks of age and intranasally (i.n.) challenged with 2.5 x 10⁵ plaque forming units (pfu) of RSV Line 19 (RSV L19; a gift from Martin Moore, Vanderbilt University – now at Meissa Vaccines, CA) per gram of body weight under isoflurane anesthesia as previously described (18 (link)). Sero+ females were allowed to recover for 3 weeks prior to immunization. Age-matched females were purchased from The Jackson Laboratory to serve as the sero- cohort. One week prior to breeding, sero+ and sero- females were immunized via intramuscular (i.m.) injection with 50mcl of vehicle (Veh.; PBS), RSV Pre-F stabilized with di-tyrosine crosslinks (PreF; Calder Biosciences, NY, NY) alone or formulated with Advax-SM™ (PreFAdx; 1 mg/mouse; Vaxine Pty Ltd, Bedford Park, Australia) or Alum (PreFAlum; 10 mg/mL, Alhydrogel, In vivoGen). The immunized female mice were paired with naïve, unimmunized male breeders one week after prime and dams were boosted three weeks later with their respective vaccine formulations. At 8 weeks post-prime, dams were challenged i.n. with RSV L19 (5 x 10⁵ pfu/gm) and culled at 4 days post-infection (DPI) using 100% isoflurane and cervical dislocation. RSV L19 was propagated and viral titers quantified as previously described (19 (link)).