Mikhail Wolfson Graduate Student Department of Chemistry Room E19-534 Phone: 617-252-1744 Fax: 617-253-2272 E-mail: wolfsonm@mit.edu CD4 T cells differentiate into two subclasses of cells (Th1/Th2) in order to help the adaptive immune system mount a variety of responses. This differentiation is controlled by many kinds of cytokines, receptors, and transcription factors. Modern biological and biochemical methods have shown that the relationships between the variuos pertinent molecules are complicated, but a molecular-level understanding has remained out of reach. Recently, imaging and molecular biochemical experimental tools are providing a more in-depth picture of Th1/Th2 differentiation. My research uses the tools developed by modern statistical mechanics to study the relevant stochastic processes. Synergy with experimental research may help elucidate a molecular basis for Th1/Th2 differentiation.