Dendritic cells (DCs) are highly efficient antigen-presenting cells that reside in many organs, including the epithelial lining of the lung. These cells are critical for the initiation of allergic responses, as well as for their maintenance in the context of continued allergen challenge. Precursor cells that give rise to DCs migrate from the blood to take residence in the epithelium. Following an encounter with an antigen, some of these DCs migrate to the draining lymph nodes where they present antigen to T cells bearing receptors specific for that antigen. These migration steps are directed in large part by the production of chemokines, small secreted molecules that cause cell migration in vitro and in vivo. The Immunogenetics Group investigates the requirements of individual chemokines and chemokine receptors for cell migration events in mouse models of asthma.