ABSTRACT
The diffuse nature of the immune system makes specific cell–cell adhesion a critically important task, and the wide variety of cell types involved makes the process very complicated. Targeting of leukocytes to regions of the body where they are needed is one aspect of immune system function that is currently of great interest due to its potential relevance in the development of new medications. The targeting process consists of adhesion of a specific subpopulation of circulating leukocytes to a specific area of vascular endothelium via cell surface adhesion receptors. Attempts to understand this process are complicated by the large number of receptors involved and the complex regulation of their expression on particular cell subpopulations. A further very important complication arises from the fact that these interactions occur within the flowing bloodstream. Research on the effect of flow on leukocyte adhesion to endothelium has revealed that different types of receptors are capable of mediating distinct types of adhesive events, and this chapter will review current understanding of this subject.
