Respiratory rates associated with G and F glycoproteins. (A) G glycoprotein. BALB/c mice were i.v. treated with purified RSV G glycoprotein isolated from RSV-infected Vero cells (G10, G100, and G1000, respectively) or PBS. ⋆, significant differences (P < 0.05) compared with PBS-treated group. (B) Comparison of F and G glycoproteins. BALB/c mice were i.v. treated with purified RSV F (F100) or G (G100) glycoprotein or uninfected VCL control. ⋆, significant differences (P < 0.05) compared with VCL-treated group. The mean respiratory rates ± standard errors from eight individual BALB/c mice were determined at time points between 0.25 and 4 h posttreatment.