FIG. 2.
Intranasal vaccination provides more protection against respiratory NMFTA1 challenge than s.c. vaccination. BALB/c mice (four to five per group) were vaccinated i.n. with 2 × 102 CFU or s.c. with 2 × 105 CFU of LVS. Twenty-one days after vaccination, i.n. and s.c. vaccinated mice and unvaccinated mice were challenged i.n. with 2 × 102 (A) or 2 × 103 (B) CFU of NMFTA1. All vaccinated mice that survived infection beyond 30 days survived at least two more months.