Parallel sets and the internal image of antigen within the idiotypic network.

Antibodies carrying the internal image of antigens and antibodies with different specificities sharing idiotypes, which were called parallel sets, have been looked on as mere curiosities or odd by-products of antibody diversity. New findings supporting the existence of these antibodies in various experimental systems were presented. In addition, molecular studies of parallel sets in an arsonate system suggested that the genes encoding for these antibodies originate from germ line genes but use a different JH segment. The functions of these antibodies within the idiotype network were discussed.