Serum IgG levels specific for TbpB and TbpA. Panel A. Serum IgG levels specific for TbpB detected on days 0, 18, 35, 63, and 82. Panel B. SerumIgG levels specific for TbpA detected on days 0, 18, 35, 63, and 82. Results are expressed as the geometric mean of antibody titers ×/÷ standard deviation. For all immunization groups n = 5 with the exception of the group immunized with NB-L2-Ctb (s.c.) where n = 4 on days 63 and 82. Arrows indicate the time at which all animals were boosted IP. Note: the axes of panels A and B are different.