Human B cell biology

Human B lymphocytes share one major distinctive feature with B cells of other higher animals, namely the ability to generate and secrete immunoglobulins. These highly specialized proteins are capable of tremendous diversity, and thereby account for much of our immune protection against invading organisms. Despite the great potential diversity possible in the specificities of immunoglobulin molecules, however, the binding of antibody to antigen initiates a limited spectrum of biologically important effector functions, such as complement activation and/or adherence of the immune complex to receptors on leukocytes. A variety of mechanisms have been elucidated that account for this, not all of which are shared by the different types of animals capable of making these proteins. The purpose of this chapter is to review the genetic, developmental, and physiologic mechanisms critical for human B cell expression of immunoglobulin.