Individually specific antigenic determinants

As defined by Oudin, idiotypy applies to determinants recognized by an antiserum prepared in the same species, and the term, individually specific antigenic determinant, has been utilized in reference to determinants defined by an antiserum prepared in a heterologous species, such as a rabbit antiserum directed to a purified human antibody or... 

Fig. 11.2. Immunoelectrophoretic patterns showing the reaction of a serum containing human anti-A substance with a rabbit antiserum to anti-A antibodies specifically purified from that human serum. In each case the human anti-A antiserum was first subjected to electrophoresis. In the lower section the unabsorbed rabbit antiserum was placed in the trough in the upper section the rabbit antiserum had been absorbed with normal human serum. The arc in the upper section which has its counterpart also in the lower section, represents the reaction with individually specific antigenic determinants in the human anti-A antibody. Reprinted, by permission, from Kunkel et al. (3). Copyright 1963 by the American Association for the Advancement of Science.

It is often important to examine and analyze individual cells.3 For example, large numbers of single blood cells can be tested for the presence of specific antigenic determinants that arise by mutation. This permits assessment of the frequency of these mutations.b The complex chemical processing of neuropeptides can be studied on the contents of a single neuron (Chapter 30) using mass spectrometry.c... 

The levels of P-D-2-acetamido-2-deoxyhexosidases A and B in the tissues and body fluids of normal individuals and Tay-Sachs patients have been measured by sensitive immunoassays specifically developed for this purpose. The results showed that normal tissues contain comparable amounts of both isoenzymes, whereas the tissues of Tay-Sachs patients contain neither the A isoenzyme nor material that carries A-specific antigenic determinants. The use of these assays in the diagnosis of Tay-Sachs disease was discussed. 

An IgG-antibody against an individual ribosomal protein binds specifically only to this protein in a ribosomal subunit. Since the antibody is divalent it can form a bridge between the identical proteins in two subunits, leading to a dimer that can be examined under Ae electron microscope. The location of the bound antibody on the subunit surface can be determined, defining the position of the antigenic determinant of a particular protein. The method relies on the fact that IgG-antibodies are able to react with specific proteins within the intact ribosomal subunits and that both subunits have discernible shapes with recognizable morphological landmarks. 

---