Specificity of the Antibody Molecule

Specificity of the Antibody Molecule

One of the greatest enigmas facing early immunologists was the specificity of the antibody molecule for foreign material or antigen. Following theories were proposed to explain this mechanism of specificity:

The selective theory: The earliest conception of theselective theory dates to Paul Ehrlich in 1900. In the 1930s and 1940s, the selective theory was challenged by various instructional theories, in which antigen played a central role in determining the specificity of the antibody molecule.

The instructional theory: According to the instructionaltheories, a particular antigen would serve as a template around which the antibody would fold. This concept was first postulated by Friedrich Breinl and Felix Haurowitz in the 1930s and redefined in the 1940s in terms of protein folding by Linus Pauling.

The clonal selection theory: The instructional theorieswere formally disproved in the 1960s, during which information was beginning to appear regarding the struc-ture of DNA, RNA, and protein. These information offered new insights into the vexing problem of how an individ-ual could make antibodies against almost anything. In the 1950s, selective theories resurfaced as a result of new experimental data and through the pioneering contribu-tions of Niels Jerne, David Talmadge, and F Macfarlane Burnet, who refined into a theory that came to be known as the clonal selection theory.