Chemotactic Profiling of Lymphocyte Subpopulations

Among a variety of trafficking signals, chemokines and their receptors represent key regulators of lymphocyte trafficking and localization under homeostatic as well as inflammatory conditions (1 ,2 ). Novel subsets of lymphocytes have been identified on the basis of their profile of chemokine-receptor expression (3 –6 ). The ability of a cell population to adhere and migrate in response to a chemokine can be tested making use of several established in vitro chemotaxis assays. Among them, the transwell chemotaxis assay is suitable to meet the needs required for a functional characterization of the migrated cells. In this chapter, we describe a transwell chemotaxis method that allows the phenotypic and functional characterization of the responding cell populations. In particular, we illustrate how chemotactic responsiveness can be combined to known cell surface markers to identify the chemotactic response profile of known subpopulations of CD4⁺ T-cells. This method can, in principle, be applied for the same purpose to different cell populations isolated from different tissues or organs.