162 CHEMISTRY OF THE IMMUNITY REACTIONS 



protein, in which case the well-known and active antiricin must rep- 

 resent an antibody for a non-protein antigen. However, the work 

 of Osborne, Mendel and Harris22 has shown that ricin is, in all proba- 

 bility, an albumin, and this, for the present at least, places ricin with 

 the protein antigens. Nucleic acid and nucleinates have been found 

 to be non-antigenic ( Wells, ^^ Taylor). 



The work of Ford is, in our estimation, the strongest evidence yet 

 presented as to the possibihty of non-protein antigens. The newer 

 developments in immunological research, moreover, make it seem 

 entirely plausible that a complex glucoside, which can be hydrolyzed 

 by enzymes, can act as an antigen. If we consider the evidence that 

 immunity consists in the development of a special power to hydro- 

 lyze foreign substances, when these substances are of such a nature 

 as to stimulate the cells to activity, and that Abderhalden and others 

 have found evidence that specific enzymatic properties appear in 

 the blood of animals injected with carbohydrates and fats, it seems 

 entirely reasonable that a toxic glucoside can have antigenic proper- 

 ties. A similar line of reasoning will apply to the question of lipoid 

 antigens. 



Lipoids as Antigens. — The evident participation of lipoids-^ in immunity reac- 

 tions, especially the complement-fixation and allied reactions, has naturallj'' led 

 to investigation of the possibility that lipoids may act as true antigens, a possi- 

 bility made conspicuous by the fact that lipoids can be substituted for true antigens 

 in the Wassermann reaction {q. v.). Bang and Forssmann immunized with ethereal 

 extracts of red corpuscles and obtained hemolysins, so that they concluded that 

 the antigenic constituent of the corpuscles is a lipoid, probably a phosphatid. 

 This work has caused much controversy and manj^ workers have failed to confirm 

 their results. ^^ It is a striking fact that when purified phosphatids, from sources 

 favorable for obtaining pure materials, are used, the results are usually negative, 

 while the positive results are generally reported with lipoids of more or less dubious 

 purity. 



"Nastin," the lipoid material from a streptothrix, has been used by Much and 

 others, who state that sera are obtained which give complement fixation reactions 

 with nastin used as the antigen. ^^ Similar results are described for the fatty 

 materials from tubercle bacilli ("tuberculonastin"). Warden^' reports securing 

 positive precipitin and fixation reactions, not only with fatty complexes from 

 bacteria and red cells, but also with artificial nii.xturcs of soaps made up to resemble 

 the cellular lipins; indeed, he states that the lipoidal antigens are more specific 

 than proteins, and infers that the specificity of antibodies is in part or wholly due 

 to the fats of the cells. 



Meyers^* has reported the production of specific complement fixation antibodies 

 by immunizing rabbits with acetone-insoluble lipoidal material obtained from tape 

 worms and cchinococcus. He has found the acetone-insoluble fraction of tubercle 

 bacilli, presumably phosphatids, to serve as antigen in complement fixation reactions 



" Amer. Jour. Physiol., 1905 (14), 259. 



"Zeit Immunitut., 1913 (19), 599. Lichtenstein (Arch. Physiol., 1915, p. 

 189) claims to have produced agglutinins for spermatozoa and yeasts with sodium 

 nucleinate from sixtim and yeasts. 



^* Bibliography on LijK)ids and Immunity given by Landsteiner, KoUe and Was- 

 serniann's llaiRll)uch, 19i;} (2), 1210; Jobling. Jour. Immunol., 191G (1), 491. 



'^ Review of literature by I.andsteiner, Jahresb. ImmunitJitsfrsch., 1910 (6), 

 209. See also Hemolysis, (!hap. ix. 



" Literature in Jioitr. Klinik d. Tiiberk., 1911 (20), 341. 



"Jour. Infect. Dis., 19I.S (22), 133; (23), 501; 1919 (24), 285. 



"Zeit. IiumunitiLt., 1910 (7), 732; 1911 (9), 530; 1912 (14), 355. 



