LESSON XVII 



ALEXIN FIXATION BY DISSOLVED PROTEINS AS ANTIGENS 

 (AND BY SPECIFIC PRECIPITATES) 



THE phenomenon of fixation of alexin by the union of antiserum 

 and antigens is not limited to cellular antigens, but occurs when- 

 ever a serum containing antibodies is mixed with its corresponding 

 protein antigen in the presence of alexin, or when alexin is treated 

 with the precipitate so obtained. The binding of complement 

 does not, however, depend on the formation of a precipitate, for 

 it occurs in dilutions at which a precipitate no longer can be seen. 



