Fig. 2.

B cells within germinal centers preferentially move from DZ to LZ. A plane was fitted to the interface region between DZ and LZ, and various measures of cell migration were plotted as a function of the shortest distance to the estimated plane. All values represent running averages of movement steps. Plotted are the mean 3D speed (A), the mean turning angle (B), the mean angle to the normal vector that defines the DZ–LZ border plane and that points toward the LZ (D), the mean angle to the estimated DZ–LZ border plane (E), and the mean displacement rate toward the LZ (F). The relationship between the angles measured in D and in E is further explained by the drawing in C.