Attempts to understand the way in which immunocompetent cells are regulated in humans, both in health and disease, will be performed. In addition, the detection of the nature of lymphocytes invading diseased tissues where an immunopathogenetic mechanism is suspected will be attempted. Initially studies are concentrating on understanding the normal physiology associated with cell activation and deactivation. An assay based on the observation that the plant mitogen Concanavalin A will activate human suppressor cells will be used. The refinement of this assay to produce a reliable technique has proceeded to the point where it is clear that cyclic fluctuation in responsiveness of human cells to mitogenic and antigenic signals probably represents alternative amplifier and suppressor stimuli. We will be assaying suppressor cell function in diseases such as sarcoidosis, infectious mononucleosis, Hodgkin's Disease, transplant patients and will also examine the effect of transfer factor on these cells.