Idiotype means that an individual differing from immunoglobulin molecule produced by B cells whose variable region has different antigen specificity. Thus it is called idiotype. The idiotypic epitopes are mainly determined by the differences of amino acid in hypervariable regions.
In the middle of last century, people found that injecting allogeneic or xenogeneic Ig into an animal could induce anti-Ig antisera. Then, Ig molecules were found two kinds of epitopes, i.e., isoforms and allotypes.
In 1955, a research found that some myeloma protein having normal Ig had response to myeloma protein originally used a immunogen. People named the new antigen specificity as individual antigenic specitficities. In 1963, some scientists immunized 50 rabbits with S. Typhimurium. Anti-typhi antibody isolated from the serum of a rabbit was regarded as immunogen, then normal rabbits was immunized and isolated from serum to anti-antibody. According the research, this kind of antibodies could only respond to anti-typhoid Salmonella antibody, whereas it failed to have precipitation reaction with 49 rabbits immunized with salmonella typhi.These results indicated that only the rabbits producing anti-S. Typhi antibodies had the special epitopes which were different from antigenic determinants of antibody molecules which were produced by other 49 normal rabbits aiming to the same antigen(salmonella typhi). It also differed from the antigenic determinants of antibody molecules determined by the same individual aiming at different antigens.So Oudin named isotype and allotype antigenic determinants as idiotype.
Anti-idiotype antibody(AId) is the anti-antibody aiming at group-specific antigen epitope (called idiotype) of the V region of the antibody molecule. Ald has a “internal image” relationship with determinant molecules of the original antigen, which stimulates the role of antigenic structure and function. So it can be a new vaccine.
Anti-idiotype antibody vaccine is a new type of immune biologics which was developed in the late 1970s. It developed towards practical areas and it had a big through in its production of vaccines, treatment of cancer and so on. This vaccine utilized antibodies against pathogenic microorganisms as antigen to immunize animals and idiotypic determinants of antibody could stimulate organism produce anti-idiotype antibody (Id;Ab2).Anti-idiotype antibodies are the internal image of initiating antigens, which can stimulate organism have immune response to initiating antigens to have protective effects.