The chemical aspects of immunity / [Harry Gideon Wells].

  • Wells, H. Gideon (Harry Gideon), 1875-1943.
Date:
1929
Catalogue details

Licence: In copyright

Credit: The chemical aspects of immunity / [Harry Gideon Wells]. Source: Wellcome Collection.

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    led to the production of antibodies (iso-antibodies). However, attempts to produce iso-antibodies arc usually unsuccessful, and when successful the activity of the antisera is low. If antigenic activity depends entirely on parenteral digestion it is perfectly possible for homologous proteins to be antigenic, for we find that whenever tissues die they undergo spontaneous proteolysis. Fibrinous exudates and extravasated blood undergo digestion and absorption, and, according to Abderhalden, all such digestion of homologous tissues and proteins leads to the appear- ance in the blood of an increased capacity to digest the same particular kind of protein, which he attributes to the presence of specific defensive proteolytic enzymes (Abwehrfermente). (See Chapter VII.) When an animal’s proteins are chemically altered they may also behave as foreign proteins and lead to auto-antibody formation. For example, if the serum of an animal is treated with formaldehyde, nitrous acid, iodin, or numerous other substances which combine with the proteins, this altered serum may serve as an antigen and give rise to the production of specific antibodies when injected into the body of an animal of the same species from which it was obtained. Probably some of the tissue proteins of an animal may be foreign to the other tissues of the same animal if they escape into the circulation. Thus, the protein of the crystalline lens is said to serve as antigen in animals of the same species (see page 71), but if true, this iso-antibody formation is not usually marked.26 The Effect of Alterations in the Protein Molecule on the Antigenic Property A. Coagulation.—Complete irreversible coagulation of proteins would, of course, render them non-antigenic, by preventing them from reaching the site of antibody formation in solution. If the coagulation is reversible, however, the redissolved protein is still actively antigenic if it has not been too much changed in composition during the processes of coagulation and resolution. Thus, if serum is coagidated by strong alcohol it can be redissolved in water after the alcohol has been removed, and the dissolved serum is antigenic.27 Egg albumin, however, is prac- tically irreversibly coagulated by alcohol, and the coagulated protein is in corresponding degree devoid of antigenic capacity.28 As a matter 28 Ilektoen. J. Infect. Dis., 31:72 (1922) 11 Horse meat protein seems to become completely insoluble, at least it loses its antigenic power, if exposed long enough to strong alcohol—60-120 days, according to Kodama [Z. Ilya. 74:30 (1913)]. ' 28 Wells, J. Infect. Dis.. 5:449 (1908).