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duction of antibodies in animals, but only the lipoid fraction takes part in serological 

 reactions in vitro. Disruption of the complex does not alter these latter reactions. 



ANTIBODIES PRODUCED BY HETEROPHILE ANTIGENS 



Heterophile antibodies can be obtained by treating rabbits with heterophile anti- 

 gens. Other animals whose tissues do not contain heterophile antigen can also be used 

 for this purpose. Guinea pigs and other animals whose tissues contain heterophile 

 antigen do not respond to such treatment, presumably because their tissues are al- 

 ready saturated with the antigen. 



In order that we may get a clear conception of the nature of heterophile antibodies 

 it will be helpful to discuss a concrete example, e.g., the immunization of rabbits and 

 guinea pigs with sheep corpuscles and with guinea pig or horse kidney. The serum of 

 rabbits treated with unheated sheep corpuscles contains two distinct hemolysins for 

 these corpuscles. One of these hemolytic bodies can be absorbed from the serum with 

 boiled sheep corpuscles or with emulsions of horse or guinea pig kidney without dis- 

 turbing the other one. Fresh sheep corpuscles will remove both hemolysins. The por- 

 tion having affinity for the boiled corpuscles is the heterophile antibody. The portion 

 absorbable by the fresh corpuscles only is isophile antibody. The quantitative relations 

 of heterophile and isophile antibodies vary in different specimens of serum. Serum 

 collected early in the course of immunization generally has an excess of heterophile 

 hemolysin, while the isophile variety is usually in excess in sera collected later. 



A pure heterophile hemolysin can be obtained by treating rabbits with boiled 

 sheep corpuscles or with emulsions of horse or guinea pig kidney. A pure isophile 

 hemolysin is obtained by absorption of a composite serum with heterophile antigen 

 or by treating guinea pigs or other animals whose tissues contain heterophile antigen 

 with sheep or goat corpuscles. 



Heterophile hemolysin has a very strong affinity for its antigen. Sheep corpuscles, 

 for example, will absorb two hundred or more hemolytic units of hemolysin of the 

 heterophile type, while they will scarcely absorb one-tenth this number of units of 

 isophile hemolysin. Also the heterophile antigen-antibody complex is very difficult 

 to disrupt. It is claimed that sheep corpuscles saturated with isophile hemolysin will 

 still absorb heterophile hemolysin, but that corpuscles saturated with heterophile anti- 

 body will not absorb any of the isophile type.' 



Heterophile antigen binds complement in the presence of heterophile serum. 

 Lecithin prepared from tissues containing the heterophile substance gives positive 

 fixation, while preparations from corresponding tissues of animals not belonging to 

 the heterophile group do not give complement fixation with heterophile serum. It 

 seems that heterophile serum contains little or no agglutinin for fresh sheep corpuscles, 

 but that corpuscles allowed to age for two or three days are readily agglutinated by 

 the serum. Trou-Hia-Hsii^ claims that the reaction with old corpuscles is specific, i.e., 

 no such reaction occurs with old ox corpuscles. Corpuscles were treated in various 

 ways but aging was the only thing that rendered them susceptible to the agglutinating 

 action of the serum. The hemagglutinins were absorbed by emulsions of guinea pig 

 kidneys. 



' Gutfeld, F. v.: Ztschr. f. Immimitatsforsch. u. exper. Therap., 34, 524. 1922. 

 ^ Trou-Hia-Hsii : ibid., p. 507. 1922. 



