it's called psychoneuroimmunology, or pni. pni studies the interface between the brain, emotions, thinking, feeling, and the immune and endocrine systems, and how those interact and talk to each other. the immune system is our most basic sense of recognition. it functions to distinguish what is our self from what is not self. for instance, a virus or a bacteria coming in from outside would be recognized as not self. our immune defense system would launch its missiles. there are two kinds of basic missiles that the immune system launches called b- and t-cells. b-cells essentially are a type of lymphocyte that makes a humeral factor. that is a factor that goes into the bloodstream-- antibodies that we all know about-- and neutralizes viruses, bacteria, parasites, through the release of antibodies. t-ces function in hand-to-hand combat. the cells actually zip in there and do battle with a cancer cell or with a bacteria. for years, we used to think that the immune system functioned in isolation. it's peculiar that anyone would thi