No effect of IFN-α on antigen-specific IgG subtypes levels induced by mBSA plus IFA. Mice were immunized twice with mBSA plus IFA with or without IFN-α in 1-week intervals followed by intraarticular injection of mBSA in PBS 21 days later. Serum was collected at days 0, 14, 21, and 28 and analyzed for mBSA-specific antibodies with ELISA by using detection antibodies specific for (A) IgG1, (B) IgG2a, and (C) IgG2b. Black bars represent control group without IFN-α treatment, and blue bars represent the IFN-α-treated group. Data are expressed as the mean absorbance (450 nm) ± SEM; n ≥ 12 (pooled data of two independent experiments).