Chemotaxis: Role in Immune Response

Chemotaxis refers to the unidirectional movement of a cell in response to a chemical gradient. Leucocytes move from a low to a high concentration of chemoattractant. In the absence of a gradient, chemotactic factors increase the random motion of leucocytes. This has been termed chemokinesis. The directed migration, or chemotaxis, of immune cells is an essential feature of the immune system. It is necessary for the development and homeostatic trafficking of immune cells and for orchestrating the juxtaposition of immune cells and antigen necessary to generate long-lasting antigen specific immunity. Chemotaxis also plays an essential role in the recruitment of leucocytes into sites of inflammation and infection. This article will briefly discuss the discovery of chemotaxis, describe the chemotactic factors and their receptors, the changes induced in cells in response to a chemotactic signal, the biological functions of chemotactic factors in the immune response, and, finally, the measurement of chemotaxis in vivo.