CD44--a Molecule Involved in Leukocyte Adherence and T-cell Activation

The study of cell surface molecules that are involved in interactions between immune and non-hematopoietic cells in various microenvironments is currently an area of great interest. One molecule that appears to be involved in multiple steps of normal immune cell function is now called CD44 and has been known previously as Pgp-1, In(Lu)-related p80, Hermes, ECM-III and HUTCH-I. Within the past year, the co-identity of all of these independently discovered molecules has become apparent, and the role of the CD44 molecule in T-cell activation has been discovered. In this review, Barton Haynes and his colleagues bring together numerous divergent lines of investigation on the CD44 molecule, review the many functional roles attributed to it, and present a unifying view of how, with numerous ligands, it may participate in several areas of normal immune cell function.