The role of direct cellular communication during the development of a humoral immune response

This chapter focuses on several interrelated models that highlight the importance of secondary lymphoid tissue function and cellular interactions during the development of a thymus-dependent (TD) humoral immune response. Immune responses occur in secondary lymphoid organs, such as lymph nodes and spleen. The induction of B cell proliferation and differentiation requires a direct physical interaction and communication between a B cell and an activated T helper (Th) cell. In the chapter, a typical lymph node is utilized to illustrate the relevant features of secondary lymphoid tissues essential for the successful development of a humoral immune response. The schematic representation of the activation of B cell proliferation in a lymph node is presented in the chapter. The activation of naive B cells and Th cells and the different steps involved in the communication process and the initiation of conjugate formation between a naive B cell and Th cell is also diagrammatically presented in the chapter. It also reviews the membrane immunoglobulin receptor complex and the role of Th cells. Th cell regulation of follicular B cell survival and the Th cell regulation of follicular B cell isotope switching are also discussed in the chapter.