Cell selection by antigen in the immune response.

Publisher Summary This chapter discusses the essential features of the antibody with respect to the interaction of antigen with preformed, cell-bound, antibody-like receptors. The effect of this interaction on individual cells is determined by the affinity of the antigen cell-bound antibody combination and results in the recruitment or selection of cells and their activation. The chapter also describes certain basic phenomena that are characteristic of the immune response and analyzes their mechanism at both the cellular and the molecular levels. These phenomena are an attempt to formulate a unified concept of the immune response as an antigen-driven proliferation and selection of specific cells that are committed to the synthesis of specific immunoglobulin molecules prior to the contact with antigen. This process, describable in thermodynamic terms, is the central biological event that can explain or predict such features of the antibody response as the progressive increase in average binding affinity of antibody produced, the effect of antigen dose on amount and affinity of antibody, the mechanism of action of adjuvants, the essential role of specific cell proliferation stimulated by antigen, the interference of humoral antibody with antigenic selection of cells, the phenomenon of “original antigenic sin,” and the induction of tolerance.