AGGLUTININS AND PRECIPITOUS A L \\ 



The Mechanism of Iso-hemagglutination. Numerous theories 

 have been offered, of which we present that of Landsteiner. It has 

 recently received support in this laboratory by the painstaking spe- 

 cific absorption experiments of Koeckert. Landsteiner considers 

 that the division into four groups depends upon the presence, dif- 

 ferently distributed in bloods, of two agglutinins, a and b, and two 

 agglutinogens, A and B. The distribution of these may be tabulated 

 as follows (Jansky classification) : 



Group Agglutinins (serum) Agglutinogens (cells) 



I. a b 



II. b A 



III. a B 



IV. A B 



Aside from the support offered by Koeckert, in his demonstration 

 that specific absorption experiments prove the presence of these 

 bodies, further confirmatory evidence is found in the fact that the 

 agglutinogenic character of cells is demonstrable in the early months 

 of life, whereas the agglutinins do not appear until near the end of 

 the first year. It is also stated that transfusion with a certain group 

 may lead to the development in the recipient of specific iso-agglu- 

 tinins for the group injected. Kolmer's work, however, shows that 

 immunization of animals with the blood of the various groups pro- 

 duces a hemagglutinative and hemolytic serum without group char- 

 acters. Karsner and Koeckert have shown that desiccation leads to 

 a loss of specificity of the sera, and that at a certain period in the 

 desiccation a common agglutinin is found which clumps the cells of 

 all groups, including Group I. This is probably in part due to 

 alterations in physical character of the redissolved sera, and to 

 alterations in hydrogen ion concentration, as shown by Karsner 

 and Collins. Therefore, although the Landsteiner hypothesis offers 

 an excellent working basis, it seems probable that an intricate 

 physico-chemical mechanism is largely concerned in the phenom- 

 enon of iso-hemagglutination. 



Iso-hemagglutinins in Lower Animals. The presence of iso- 

 hemagglutinins in animals other than man is extremely irregular 

 and infrequent. Certainly no classification into definite groups has 

 so far been demonstrated. In our own experience the examination 

 of from ten to twenty members each of dog, rabbit, cat, and guinea- 

 pig species has failed to show iso-hemagglutinins, but others who 

 have examined larger numbers have found an occasional instance 

 of iso-hemagglutination. 



Relation of Iso-hemagglutinins to Blood Transfusion. The 

 principal importance of iso-hemagglutinins and the related iso-hemo- 

 lysins in human medicine relates to the transfusion of blood, a thera- 

 peutic measure which civil and military practice have shown to be 

 of the utmost value in combating secondary anemia following 

 hemorrhage. It is also recommended for prolonged sepsis with or 

 without severe anemia, for primary anemias, and for certain other 



