The Deeper Problems

Burnet, Sir Macfarlane. "The integrity of the body." 1962, Chapter 13 pp 176-183

These are all comments made in the last chapter of Burnet's book. They are extremely prescient.

Immunology is not yet fully integrated into the pattern of general biology . . .

. . . how immunology may in the future both help the gradual formation of the elusive integrated picture of biology and be interpretable in terms of wider concepts.

There is no special reason why the evolution of defense against infection should necessarily involve an elaborate self-recognition mechanism.

There must be many millions of errors (mutations) occurring every day of our lives, and complex and long-lived multicellular animals could not have evolved unless some means of dealing with this eventuality had been developed.

. . . within the body there has developed a means for the recognition of potentially dangerous somatic mutation, and that this is the basis on which the immunological functions of the vertebrates have been evolved.

Very recently there have been a number of indications that immunological recognition may be derived from an aspect of the processes by which all multicellular animals succeed in maintaining a characteristic morphological and functional unity. In its most general formulation this capacity must involve an interchange of "information" between cells. A cell seems to be able to "recognize" whether another cell is in contact with it or not and in some instances whether the adjacent cell is of its own type or another. For the appropriate reactions to take place, which allow, for instance, the reconstruction of a traumatized area into something functionally and morphologically equivalent to its previous normal form, one must postulate a rather elaborate structure of effector and receptor patterns, chains of stimulation and of feed-back controls. Effector and receptor patterns as factors in morphogenesis have been sponsored by Weiss for many years, with a mutual relation of antigen-antibody type. Here then is a potential basis on which a specialized recognition function of lymphoid cells may have been evolved.

All this is rather thin speculation and it may appear foolish to attempt to interpret immunology in terms of embryonic differentiation and morphogenesis about which we know very little.

. . . a hypothesis linking immunological recognition on the one hand with embryonic differentiation and morphogenesis on the other may be helpful to both.

The hypothesis that immunological recognition has been evolved from and has remained part of the control system by which the body maintains its structural and functional integrity is no more than a hypothesis.