214 CHEMISTRY OF THE IMMUNITY REACTIONS 



complement. Amboceptors are not inactivated by shaking, as is com- 

 plement, but they are destroyed alike by nltraviolet rays, and both 

 resist a;-rays."^ 



According to Pfeiffer and Proskauer,^^ digestion of the globulin 

 precipitate, in which amboceptors are carried down, does not destroy 

 their activity completely even when all the proteins are thus re- 

 moved. Removal of the nucleo-albumin or nuclein does not remove 

 the amboceptors from the serum. Immune serum kept three months 

 in alcohol yielded an extract with distilled water that was rich in 

 immune bodies, but almost free from protein. Pick, Rhodain, and 

 Fuhnnann found that immune bodies are precipitated entirely in the 

 euglobulin fraction of the serum protein. From these experiments 

 it has been thought by some that the bacteriolytic amboceptor is not 

 itself a protein, although closely associated with the serum globu- 

 lins.'® 



CYTOTOXINS 



Just as precipitins can be obtained for proteins derived from other 

 sources than bacterial cells, so also upon immunizing an animal 

 against various types of cells other than bacteria, substances appear 

 in its serum that exercise a destructive effect upon the type of cells 

 injected. In other words, the reactions of animals to infection are 

 not specially devised for combating bacteria and their products, but 

 can be equally exerted against non-bacterial cells and their products. 

 In the case of soluble proteins, as before mentioned, the antibodies 

 show their effects by precipitating them, with agglutination of the par- 

 ticles into flocculi and perhaps a subsequent digestion ; in the case of 

 cells, whether bacterial or tissue cells, the antibodies cause agglutina- 

 tion and loss or impairment of vitality. This injury may be mani- 

 fested by loss of motion in the motile cells (bacteria, spermatozoa, 

 ciliated epithelium) or by solution of their contents (bacteriolysis, 

 erythrocytolysis, leucocytolysis, etc.), or by cell death without marked 

 morphological alterations (B. typhosus, spermatozoa). If we inject 

 red corpuscles, leucocytes, spermatozoa, renal epithelium, or any other 

 foreign cell, the reaction is as specific as it is if we inject bacteria, and 

 of exactly the same nature. Therefore, all that has been said pre- 

 viously concerning bactericidal substances and agglutinins can be 

 transposed to apply to immunity against tissue cells. As a matter of 

 fact, however, the transposition is generally made in the other direc- 

 tion, for red corpuscles are much easier cells to study than bacteria, 

 because their hiking gives ])ronipt and readily recognized evidence 



i*aScamcli, Uiochoni. Zeit., 1015 (60). 102. 



in Cent. f. Bakt., 189G (19), 101. 



10 Ascoli found that tlie active substance of antliracidal seruni, which is not 

 an amhoceptor, is contained in the pseu(h>-j,'h'hulin fraction of asses' serum, but 

 in poat's serum part is in tlie euf,'h)bulin fraction. (IJiochem. Centr., 1006 (5), 

 458.) 



