Figure 5: Systemic antibody response to RSV antigens. Serum samples were collected at 2 week intervals after mice were immunized with PBS, RSV, and DCNP via the i.n. route, and with naked DR-FM2G DNA via i.m. route. RSV specific antibody isotype IgG1 (A) IgG2b (B), IgG2a (C) and IgA (A) were determined by ELISA. Results are presented as an average of data from three groups in triplicate; error bars represent standard deviation. * Significantly different (P < 0.05) from PBS group; **, significantly different (P < 0.05) from PBS and DNA groups. P values were calculated by the Studentís t-test.