Human lymphocytes and iDCs migrate to IRBP and S-Ag. Freshly isolated human B cells (95% purity), 16-hour IL-2–cultured lymphocytes (Lymph; 90%), or monocyte-derived immature dendritic cells (iDC; 95%) were placed in the upper chamber of a micro-Boyden chemotaxis chamber. The number of migrated cells in 3 high-powered fields (× 200) was determined by light microscopy. 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. • indicates bovine IRBP, while ▪ represents bovine S-Ag. Cells tested include lymph nodes cells (left), B cells (middle), and iDCs (right). For B cells, a control chemoattractant BCA-1 (CXCL13; □) is shown at 100 ng/mL. StatView Student t test (Abacus Concepts, Berkeley, CA) with ^*P ≤ .0001 for maximum chemotactic responses vs “0” control; ^**P ≤ .005. N ≥ 2. A representative experiment is shown. Error bars indicate standard deviation (s).