Although one of the major properties of the cell membrane is to recognize and respond to various signals with which it comes in contact, the cells of the immune system have the additional ability to recognize substances which are foreign and potentially harmful. Thus these cells bear receptors for interaction with foreign substances (antigens). Regulation of an immune response involves different cells and hormone-like molecules and their interactions also depend on specific recognition molecules or receptors on the surface of these cells. James Hildreth's research is directed at understanding the structure and function of surface membrane molecules that serve in the recognition and regulation of specific cellular interactions in immune functions. Dr. Hildreth is a young investigator who has been making significant contributions in this area. To pursue these studies he has been awarded a Presidential Young Investigator award.