CXCR3-transfected 300-19 cells migrate to both IRBP and S-Ag. Various concentrations of S-Ag or IRBP placed in the lower well of a micro-Boyden chemotaxis chamber. (A-B) Parental 300-19 or CXCR3-expressing 300-19 cells were placed in the upper wells of a micro-Boyden chamber. The mean number of migrating cells and corresponding standard deviation are graphed on the y-axis while ligand concentrations are shown on the x-axis. ▪ represents bovine S-Ag; ▨, IRBP; ▦, CXCL11; and □, 1-20 aa S-Ag peptide (A) or media control (B). ^*StatView Student t with P ≤ .0001 for maximum chemotactic responses vs “0” control; #P not significantly different from control. n = 3. (C-D) CXCR5-transfected HEK-293 cells migrate to IRBP. Various concentration of S-Ag or IRBP placed in the lower well of a micro-Boyden chemotaxis chamber. Parental human embryonic kidney cells (HEK-293) or CXCR5-expressing HEK cells were placed in the upper wells of a micro-Boyden chamber. The mean number of migrating cells and corresponding standard deviation are graphed on the y-axis while ligand concentrations are shown on the x-axis. ▪ represents bovine S-Ag; ▧, human S-Ag; ▨, IRBP; ▦, CXCL13; and □, media control. ^*StatView Student t with P ≤ .0001 for maximum chemotactic responses vs. “0” control; ^**P ≤ .005. n = 3.