Figure 2. RSV neutralizing titers in primed mice and lung viral clearance after challenge.
(A) Neutralization titers at 3 weeks after prime vaccination of 2 weeks (2wks) old and adult mice. A line indicates a background titer. (B-C) Lung RSV titers after challenge. naïve R. (unimmunized mice) and immunized mice were challenged with 3.5×105 PFU RSV A2. BALB/c mice (n=5) were immunized with F protein or F protein with alum, CpG, MPL or CpG+MPL. Individual lungs were collected at 5 days after RSV challenge and RSV titers were determined by an immunoplaque assay. The linear line represents the lower limit of detection (LLOD). PBS: unimmunized mice, Naïve R: unimmunized+RSV, F protein: 0.1 μg of F protein+RSV, Fp+Alum: F protein 0.1 μg with alum 50 μg+RSV, Fp+CpG: F protein 0.1 μg with CpG 4 μg+RSV, Fp+MPL 1 μg: F protein 0.1 μg with MPL+RSV, Fp+C.+M.: F protein 0.1 μg with CpG 4 μg and MPL 1 μg combination adjuvants+RSV. Results are presented as mean ± SEM. Statistical significances were performed by one-way ANOVA in GraphPad Prism; *** p<0.0001.