Locomotion and chemotaxis of lymphocytes

The behaviour of locomotor T and B lymphocytes and the chemoattractants to which they respond in vitro are reviewed. Following activation, T cells respond by locomotion and chemotaxis to cytokine attractants including IL-15 and IL-2 and several chemokines. In activated B cells chemotaxis may be signalled through the antigen receptor. Conversely resting lymphocytes respond poorly to the above signals though their locomotion is activated by contact with high endothelial venular cells. These differences in locomotion between resting and activated lymphocytes, together with differences in adhesion, may explain why activated lymphocytes migrate preferentially into inflammatory sites while resting cells recirculate.