Neonatal Viral Infection in Mice

Adult (8–14 week old) male and female CB6F1 mice were obtained from Jackson Labs (Bar Harbor, ME) or bred in-house. Neonatal CB6F1 mice were bred in-house, the offspring of mating BALB/c female mice with C57Bl/6 males. TCR transgenic mice were produced by NCI-Frederick Laboratory Animal Sciences Program (LASP) transgenic mouse model service and subsequently bred as heterozygotes in-house as previously described (25 (link)). Batf3−/− BALB/c and C57Bl/6 mice were obtained from Jackson Labs and bred in-house to obtain both neonatal and adult Batf3-deficient hybrid mice. All mice were housed in our animal care facility at NIAID under specific pathogen-free conditions, and maintained on standard rodent chow and water supplied ad libitum. Neonatal mice were infected at 7 days old. Mice were anesthetized using isoflurane (3%), and infected intranasally with 2×10⁶ PFU of live RSV in 10% EMEM (100 μl for adults, 25 μl for mice infected at 7 days of age). For influenza infection, neonates were infected intranasally with 25μL of PBS containing 600 TCID₅₀ of influenza/PR8 using the same method. All mice were euthanized by lethal overdose of pentobarbital (250 mg/kg). Experiments involving co-administration of either OVA-Alexa647 or OVA-DQ (Invitrogen) were performed by adding 50 μg protein/mouse directly to virus preparations prior to intranasal administration.