Cell Locomotion and Chemotaxis: Basic Concepts and Methodological Approaches

The locomotion of leukocytes and its control by environmental agents is crucial, not only for recruiting cells into inflammatory sites, but also for their migration through lymphoid tissues, and thus for the contact interactions of antigen-bearing accessory cells with lymphocytes in induction of the immune response. The methods used to measure locomotion must be capable of giving reliable information about these events. The definitions of terms such as chemokinesis and chemotaxis are discussed, and the methods currently available for measuring locomotor responses, with their advantages and limitations, are reviewed. It is suggested that the most popular method, the filter assay, gives partial and sometimes misleading information and should be supplemented with other methods including visual assays. No single method gives full information about cellular locomotor behavior.