ABSTRACT
The adaptive immune response is an extremely complex series of events that result in the activation of effector cells with the goal of eliminating structures not recognized as self. This chapter describes the nature of antigens, the structures recognized by T and B lymphocytes, and the factors that determine the magnitude of the adaptive immune response. The stimulation pathways of T and B lymphocytes, the role of accessory cells, as well as the cooperation of T helper lymphocytes and B lymphocytes in antibody responses are discussed in detail, as well as the differences between T-dependent and T-independent antigens. Also discussed are the activation pathways of cytotoxic T cells, including the allostimulation causing graft rejection and alternative pathways of antigen presentation to cyotoxic T cells involved in the elimination of intracellular organisms. The chapter ends with a discussion of the major subpopulations of helper T lymphocytes and their significance in the development of immunological memory.
