The shared epitope (SE) accelerates endogenous reactive oxygen species (ROS) production. (a) Time-course ROS levels in representative SE-positive (red line) and SE-negative (blue line) B-lymphocyte cell lines. (b) ROS production rates in B lymphocytes. Results are shown as the mean ± standard error of the mean fluorescent units per minute (FU/minute) during the linear late phase of the ROS curve (80 to 200 minutes). Data of the SE-positive (SE+) and SE-negative (SE-) groups were compiled from three to five consecutive experiments in each cell line. The values in parentheses represent the number of donors in each group. (c) ROS levels in M1 cells stimulated with 2.5 μg/ml of either SE-positive hepatitis B core (HBc) capsids (HBc*0401, red line) or SE-negative HBc capsids (HBc*0402, blue line). (d) ROS levels in M1 cells stimulated with 100 μg/ml of either an SE-positive 15 mer peptide (65–79*0401, red circles) or an SE-negative 15 mer peptide (65–79*0402, blue circles). Calculations of p values in (c) and (d) were based on paired t test analysis. DCF, dichlorofluorescein.