Figure 1. F protein immunization and challenge study in mice.

1. Schematic representation of mouse immunization and challenge schedule. Female BALB/c mice (n = 5 per group; 4–6 weeks old) were immunized with single dose of live RSV‐A2 virus (10⁴ pfu dose) intranasally, or two doses given i.m. with 20 μg of RSV pre‐fusion or post‐fusion form of F protein or F peptides from RSV strain A2 with Emulsigen adjuvant, or with KLH or with PBS as a control. After the second immunization, blood was collected from the tail veins on day 35. On day 42, mice were challenged intranasally with 10⁶ PFU/10μl of RSV rA2‐Line‐19F‐FFL. Mice were sacrificed on day 5 post‐challenge, when lungs and blood were collected.
2. Alignment of antigenic site peptides within the RSV‐F protein used for mice vaccination in the study. Previously described antigenic sites (sites ϕ, I, II, and IV) are shown above the F protein schematic, and the antigenic site peptides used in this study are depicted below.