The intercellular adhesion molecules (ICAMs) play a prominent role in regulating the migration and activation of both dendritic cells (DCs) and T lymphocytes in the immune system. Recent observations have demonstrated that both leukocyte function-associated molecule 1 (LFA-1) and DC-specific ICAM-grabbing nonintegrin (DC-SIGN), two structurally unrelated adhesion receptors, regulate the function of leukocytes and DCs by binding to the same ICAMs. Here, we focus on the structure-function relationships of DC-SIGN and LFA-1 to obtain an insight into their role in the migration and activation of DCs and T cells in the control of immunity.