The physiologic function of the immune system is simplistically viewed as a method to specifically respond and eliminate an initiating antigen. This process is mediated by a network of specialized cells and depends upon a pathway involving recognition, activation, differentiation and response of lymphocytes. This simplistic view is significantly more complicated when one is examining the biological nature of this response in greater detail. Not only are the specific front-line cells activated, but also a series of effector mechanisms is potentiated by antigenic stimulation that elicits a larger host response.These effector mechanisms are generally mediated by a group of proteins called cytokines. For activated T lymphocytes, these molecules are termed lymphokines. Some T cells produce cytokines to regulate lymphocyte activation, growth, and differentiation, while other T-cell populations principally function to activate and regulate inflammatory cells. These T cell-derived cytokines are consequently ...