Locomotion of memory, naive, and GC B lymphocytes. Locomotory activity of IgD⁻CD38⁻ memory cells, IgD⁺ naive cells, and IgD⁻CD38⁺ GC B cells in the presence (□) or absence (▪) of 1 ng rTNF. Data are means ± SE from four experiments. In the presence of rTNF, memory and naive, but not GC, B cells migrated faster than the corresponding unstimulated cell fractions (P < .05, nonparametric Mann-Whitney U-test). Furthermore, in the presence of rTNF, memory and naive B lymphocytes displayed a significantly higher degree of locomotion than GC B cells (P < .05) and memory B cells migrated faster than naive B cells (P < .05).