Activation and function of gamma delta T cells.

T-cell receptor gene rearrangements in gamma delta T cells have been the subject of intense molecular investigations. This year, much has been learned about the mechanisms controlling this process. However, the specificity and function of gamma delta T cells still remains enigmatic. The application of molecular technology including the availability of mutant mice lacking defined T-cell populations and immunologically relevant surface proteins is beginning to provide answers as well as some surprises.