THE COMPLEMENT FIXATION TEST 

 TITRATION OF HEMOLYSIN 



327 



Incubate all tubes in water bath at 37 C. for one-half hour and 

 read. 



A. 0.9% salt solution. 



B. 1% dilution of inactivated immune rabbit serum in salt solution. 



C. 1% suspension of washed sheep-blood cells. 



D. Titrated guinea pig serum diluted so that 0.1 c.c. contains 

 1.5 times the titre. 



E. + indicates complete hemolysis. 

 indicates no hemolysis. 



* indicates a variation in the reaction according to the strength of 

 the hemolysin. 



The smallest quantity causing complete hemolysis is called the 

 titre. 



A titration of this reagent is made to determine the 

 smallest quantity that will prevent hemolysis in the presence 

 of 1.5 times the titre of complement and the hemolysin, 

 sheep cells and immune serjim. In other words, we must 

 determine the smallest quantity of antigen that will fix 

 the amount of complement used in the test. 



TIRATION OF THE ANTIGEN 



Incubate for half an hour in a water bath at 37 C., then add the hemolytic sys- 

 tem as follows: 



