The immunogenicity of immunoglobulin idiotypes in syngeneic systems is a rather rare phenomenon. Very few studies have attempted to determine the mechanisms underlying the anti-idiotypic response that certain autologous idiotypes can elicit. Furthermore, the studies addressing a possible physiological role for such behaviors are even less. In the present article, the results of the characterization of a highly immunogenic idiotype are reviewed and compared with some related works on the subject. We finally propose a possible immunoregulatory role for idiotypic immunogenicity.