AGGLUTINATION 17'.) 



also present in the various organs, and to greater or less extent in 

 the other body fluids, excepting usually the spinal fluid (Greer and 

 liecht).''* The place of their founation is unknown, but they can be 

 formed by spleen tissue grown in artificial cultures.'" vSince bacteria 

 contained within a collodion sac iinplantcfl in an animal give rise to 

 the production of agglutinins, it is evident that the agglutinogens 

 are diffusible to some extent, at least, through collodion. Old cul- 

 tures of bacteria contain free agglutinogens, probably liberated from 

 disintegrated cells, and filtrates of such cultures will neutralize ag- 

 glutinins, showing both that the agglutinogens arc filtei-al)le, and 

 that the reaction of agglutination is a chemical one and not dependent 

 upon the presence of cells. Agglutinogens are said to pass through 

 dialyzing membranes, while agglutinins do not, so it is evident that the 

 agglutinogen is of smaller molecular dimensions than the agglutinin, 

 just as toxin molecules are smaller than antitoxin molecules. Agglu- 

 tinogens are not destroyed by formalin, heat, or ultraviolet rays in 

 concentrations sufficient to kill the bacteria containing them.'' 



Just what constituent of the bacteria acts as the stimulus to the 

 production of the agglutinin is unknown. Apparently', there are 

 at least two bacterial substances with this property, one of which 

 seems not to be a protein, since it is soluble in alcohol, gives no biuret 

 reaction and resists temperatures up to 165°. The other gives all 

 protein reactions, and is destroyed by heating to 62°. We consider, 

 therefore, that there are two agglutinogens in the bacterial cell, one, 

 thermostable, the other, thermolabile. The difference in the func- 

 tion of these two agglutinogens is still a matter of dispute. Likewise, 

 the question as to whether they occur in the membrane or within the 

 bacterial cell is still open, but Craw found that the insoluble residue 

 of crushed typhoid bacilli, after being washed free of all soluble con- 

 stituents, was but slightly agglutinated by active serum; therefore, 

 the agglutinogens are probably soluble intracellular substances. Stuber 

 holds that bacterial agglutinogens are lipins.'^ 



Properties of Agglutinins. — Like most of the other immune substances, agglu- 

 tinins are precipitated out of the serum in the globulin fraction. All attempts 

 to separate them from proteins have been unsuccessful. Stark'^ found that 

 trypsin does not attack the agglutinins readily, corresponding to the resistance 

 of the serum globulins to this enzyme; alkaline papayotin solution destroys them 

 slowly, while pepsin acts more rapidly. Alkalies are destructive even when quite 

 dilute, while acids are much less harmful. The temperature resistance of agglu- 

 tinins seems to be variable, plague agglutinin being destroyed at 56°, while purified 

 typhoid agglutinin may resist 80°-90°; most agglutinin serums lose their activity 

 at 60°-65°. The rate of reaction of agglutinins increases with the temperature, 

 as long as this is not high enough to injure the reacting substances.^'* They are 

 not precipitated by specific precipitins, but are readily absorbed by charcoal. 



3 Jour. Infect. Dis., 1910 (7), 127. 

 >" Pryzgode, Wien. klin. Woch., 1913 (26), 841. 

 ^1 Stassano and Lematte, Compt. Rend. Acad. Sci., 1911 (152), 623. 

 »2 Biochem. Zeit., 1916 (77), 388; also Bauer, Biochem. Zeit., 1917 (83), 120. 

 1' Inaug. Dissert., Wiirzburg, 1905. 

 1* Madsen, et al, Jour. Exper. Med., 1906 (8), 337. 



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