Genetics, Expression, and Function of Idiotypes

In this article the authors speak about the network of idiotypes in the immune system. They start by defining the vocabulary they are going to use. They then discuss the structural basis of idiotypic determinants and of their complementary anti-idiotypic antibody binding sites. Idiotopes and anti-idiotopes are encoded by antibody V,D, and J genes. The idiotypic repertoire thus reflects the repertoire of these genes as they are expressed, selected, and somatically modified in the immune system. The idiotypic repertoire, its genetic basis and its selection in ontogeny, is a main theme of the present view. This relates directly to the functional idiotypic network: Which rules do idiotypic interactions in the immune system follow and what is their physiological role? Idiotypic reactions seem to be involved in the growth control of lymphocyte clones with defined receptor specificity and may thus be essential for the generation of a diverse system of interacting cells. They also stabilize the expression of a given receptor repertoire in active immune responses. Idiotypic interactions occur within the compartment of B lymphocytes, but they also involve T cells. The authors discuss the crucial issue of whether or not recognition of B-cell idiotypes is one of the principles by which T cells are selected in the immune system.