CYTOKINE REGULATION OF THE IMMUNE RESPONSE
Cytokines are responsible for regulating the activities of the cells that mediate immune / inflammatory reactions. My research is focused on the first cytokine to be described, interleukin 2 (IL-2). IL-2 is a 15 kDa protein secreted by antigen-activated T cells that promotes the proliferation and enhances the secretory capacities of all of the major types of lymphocytes, including T cells, B cells and natural killer (NK) cells. The IL-2 stimulated clonal expansion of antigen-selected T cell and B cell clones determines the tempo and magnitude of antigen-specific immune responses, and forms the cellular basis of immunologic memory. Detalied smolecular studies over the past 20 years have led to the development of a new theory of how the immune system discriminates bewteen self and non-self (i.e. antigens). Each cell actually counts the number of "hits: it receives from both the antigen receptors, as well as the IL2 receptors, and only responds when a critical number of receptors have been triggered. Then each cell responds in an all-or-none fashion, leading to the "Quantal Theory of Immunity". Experiments by others have shown that when this crucial quantal control of the decision to divide is usurped by mutations of either the receptors, signaling pathways, or the transcription factors that regulate cell cycle genes and cellular survival, then autonomous cell growth results, aka "Cancer".