Fig 4.

Immunization with the vaccine candidate protects BALB/c mice against RSV challenge. Mice were immunized i.p. three times as described in Materials and Methods. Three weeks after the final immunization, mice were challenged i.n. with 10⁵ TCID₅₀s/100 μl RSV A. At 5 days postchallenge, lungs were removed. RSV replication in lungs was measured using RT-PCR. (A) Semiquantitative RT-PCR products. Lane 1, DL2000 DNA maker; lane 2, PBS group; lane 3, pIL-23+G1F/M2 group; lane 4, pIL-27+G1F/M2 group; lane 5, pIL-23+ pIL-27+G1F/M2 group; lane 6, G1F/M2 group. (B) Relative expression of RSV N mRNA by qRT-PCR. The fold reduction of RSV N-gene expression in each experimental group was calculated by comparison to that in PBS-treated mice (100%). Results are means ± SDs of 5 or 6 mice per group and are representative of two experiments.