T-cell–dependent immune response of M17^–/– mice and generation of memory B cells. (A) Primary immunization with 50 μg (left panel) or 10 μg (right panel) NP-CG in alum. Each circle represents one mouse. Bars indicate the geometric means. Closed circle indicates M17^+/+ mice; open circle, M17^–/– mice. (B) Secondary immunization with 10 μg NP-CG without alum of mice previously immunized with 50 μg (left panel) or 10 μg (right panel) NP-CG. (C) Amount of splenic IgG1⁺ memory B cells 9 weeks after the secondary immunization. Numbers are in percent plus standard deviation of total B cells (n = 5). The differences were not statistically significant.