This proposal requests support for a Keystone Symposia meeting entitled Immunoregulatory Networks, organized by Dario A.A. Vignali, Steven F. Ziegler and Hilde Cheroutre, which will be held in Breckenridge, Colorado from April 1 - 6, 2011. Immunoregulatory networks play a pivotal role in preventing autoimmunity and other inflammatory diseases, but also restrict anti-tumor immunity and modulate immune responses to pathogens. While regulatory T cells (Tregs) are a central component of this network, there are many other cell populations and molecular pathways that contribute to these networks. The Keystone Symposia meeting on Immunoregulatory Networks will focus on how different cellular and molecular components integrate and cooperate to prevent autoimmunity and control inflammatory immune responses. This meeting will dissect our current understanding of four key areas: transcriptional control of regulatory cell development and homeostasis, molecular control of immunoregulatory networks, mechanisms of regulatory function, and regulatory T cell plasticity. We also aim to discuss how Tregs interact with different cell types or utilize different cytokines that modulate or indirectly mediate their activity. Finally, we will assess how the advances presented can be utilized to develop novel therapies for autoimmune diseases, inflammatory diseases, chronic infections and cancers. PUBLIC HEALTH RELEVANCE: The immune system is a complex conglomeration of molecules and cells that work synchronously to fine tune responses to pathogens and modulate disease states. These fundamental biological processes are mediated by "immunoregulatory networks", an equally complex network of interactions, checks and balances. The Keystone Symposia meeting on Immunoregulatory Networks will focus on how different cellular and molecular components integrate and cooperate to prevent autoimmunity and control inflammatory immune responses.