INTRODUCTION TO IMMUNE FUNCTION
Part III presents an overview of the current state of knowledge of immune function and the interaction of nutrition with immune response. Chapter 7 reviews the wealth of recent research that has led to exciting advances in the understanding of interactions among nutrition, immunity, and infection. It is now established that undernutrition is associated with consistent changes in immune responses that include number of T-cells, lymphocyte response to mitogens and antigens, phagocyte function, secretory IgA antibody response, complement activity, and NK cell activity. The nature of cytokines, the so-called hormones of the immune system, is explored in Chapter 8. Their biochemistry and classification, mode of action, and measurement are discussed as well as the potential of cytokines as an additional tool for assessing effects of nutrition and stress interactions.