[Molecular mechanisms underlying cell adhesion--molecules mediating lymphocyte migration]

Adhesion molecules play crucial roles in a variety of in vivo responses such as development of various tissues in embryos and also in the body defence mechanism in the postnatal period. Defects in adhesion molecules thus result in various pathological disorders. Recent investigation has identified a large number of novel adhesion molecules, particularly those involved in the extravasation of leukocytes including lymphocytes. However, there still appears to be a substantial number of unidentified adhesion molecules. In addition, signal transduction as well as regulatory mechanisms of adhesion molecules remain not fully explored. I will herein describe general characteristics of adhesion molecules and also discuss issues that need to be urgently resolved in the field of cell adhesion.