Influence of ginseng on serum IgG and isotype antibodies specific for RSV. (A) Total serum IgG antibody. (B) Serum IgG1 isotype antibody. (C) Serum IgG2a isotype antibody. As shown in a diagram of experimental schedule, BALB/c mice (n=5) were orally administered ginseng at a dose of 25 mg/kg/day for 80 days. During this period, mice were intramuscularly immunized with FI-RSV. Blood samples were collected individually at 3 weeks after priming (first) and boost (second) immunizations with FI-RSV, and 100-fold diluted sera were used to determine total IgG and IgG isotypes by ELISA coated with FI-RSV. Optical densities were read at 450 nm, and values are the mean±SEM. *P<0.05; **P<0.01; ***P<0.001. PBS, PBS mock control mice; Ginseng, Ginseng mock control mice; PBS+FI-RSV, FI-RSV immunization during PBS oral treatment; Ginseng+FI-RSV, FI-RSV immunization during ginseng oral treatment. The data were presented from 2 independent experimental assays. ELISA, enzyme-linked immunosorbent assay; FI-RSV, formalin-inactivated respiratory syncytial virus; IgG, immunoglobulin G; PBS, phosphate-buffered saline.