CHAPTER XII 



MECHANISM OF ANTIGEN-ANTIBODY REACTIONS 

 CELLULAR AGGLUTINATION 



Period of Discovery and Early Investigations. — The ]ieriod of 

 discovery of the phenomenon of bacterial agglutination by im- 

 mune serum began with Charrin and Roger (1889) and ended 

 with Bordet (1895). The next year the value of the reaction in 

 diagnosis and its relative specificity^ was described by Gruber, 

 Gruber and Durham, Widal, Griinbaum and others. 



Gruber 's Theory of Agglutination (1896). — Gruber suggested 

 the name ''agglutination" for the phenomenon and offered a 

 theory explaining it. He believed that the clumping was caused 

 by the action of agglutinin (antibody) upon the bacterial cell 

 membrane whereby the latter became more viscous. In his opinion 

 this change in the membrane caused the bacteria to stick together. 

 This was really the first suggestion that "cohesive forces" might 

 be a factor as shown recently by Northrop and De Kruif (1922). 



Bordet 's Early Work. — It is quite probable that all of this 

 work was inspired by Bordet 's observation (1895) of the phe- 

 nomenon of agglutination while lie was engaged upon tlie study 

 of the phenomenon of Pfeiffer. The next year (1896) lie turned 

 his attention to the mechanism of agglutination and published the 

 results of his experimental work two years later (1898). 



Discovery of Precipitins. — In the meantime, Kraus (1897) 

 made an important discovery that has directly or indirectly in- 

 fluenced our conceptions of antigen-antibody I'eactions in general. 

 He observed that a specific pi'ecipitate was formed when cholera- 

 immune serum was mixed Avith filtrates from an old broth culture 

 of the vibrio of Asiatic cholera. This was the first work done on 

 precipitins. Two years later Tchistovitch noted that the blood 

 serum of rabbits vaccinated against horse serum yielded a specific 

 precipitate when mixed with horse serum. Similar results were ob- 

 tained when eel serum was used as an antigen. 



Dineur's Hypothesis of Agglutination. — Following Kraus 's 

 discovery and prior to Bordet 's publication, Dineur (1898) ad- 



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