Regulation of immunity at the cellular level

Abstract

The origin of pluripotentiality of the immune system in an individual constitutes a major challenge for students of immunology. A vast number of different substances can be shown to be antigenic in an individual, such that their introduction will induce antibody synthesis. These antibodies, mostly detected as serum immunoglobulins, are distinguished by their Capacity for specific combination with the inducer, the antigen. As the specificity of the antibody towards a given antigen can be shown to reside within the amino acid sequence of the molecule by unfolding-refolding experiments (Haber, 1964), it is generally accepted that the antigen-combining capacity of an antibody molecule is under genetic control. So far, studies trying to disclose any unique features of immunoglobulin versus other systems of protein production have failed to do so. No commonly accepted theory yet exists to explain how this multiplicity of immunological potentiality is created at the level of DNA and it is considered beyond the scope of this article to try to cover in detail the various attempts to solve this problem. The reader is referred to a recent review (Lennox & Cohn, 1967) for further details on this subject. It is the intention of the author to describe how pluripotentiality of the immune system operates at the cellular level and to describe and discuss in more detail how regulation of the expression of immunological capacity takes place at the single cell level.