Abstract
An important aspect of the developmental maturation of lymphocytes is their capacity to locate and enter lymphoid organs with great rapidity and specificity and to follow certain routes within these organs for the attainment of particular immunological capabilities. It is now known that this “homing response” to lymphoid organs involves specific glycoprotein receptors on the lymphocyte cell surface. The biochemistry of these receptors and their significance in normal and pathological immune responses are discussed.