930 EXPERIMENTAL INFECTION AND IMMUNITY 



EXPERIMENT 82. INACTIVATION AND REACTIVATION OF COMPLEMENT 



1. Heat 1 c.c. of the 1: 10 dilution of fresh rabbit immune serum used in the pre- 

 ceding experiment to 56 C. for half an hour (in a water-bath). 



2. In a test-tube place a cubic centimeter of this heated serum and 1 c.c. of a 2^ 

 per cent, suspension of sheep cells and sufficient salt solution. Shake gently and 

 incubate for one hour. 



(a) Does hemolysis occur? 



(b) How do you explain the result? 



(c) What is meant by inactivation of complement? 



(d) Is complement thermostabile? 



3. Add to the tube 1 c.c. of fresh guinea-pig serum diluted 1 : 10 and reincubate 

 for an hour. 



(e) Has hemolysis occurred? 



(f) How do you explain the result? 



(g) What is meant by reinactivation? 



EXPERIMENT 83. GENERAL PROPERTIES OF COMPLEMENT 



1. Secure antisheep amboceptor the hemolytic unit of which is known by pre- 

 vious titration. 



2. Prepare a 2^ per cent, suspension of washed sheep corpuscles. 



3. Into a series of four test-tubes place the following: 

 Tube 1 : 1 c.c. of fresh guinea-pig serum diluted 1 : 20. 



Tube 2: 1 c.c. of guinea-pig serum (1:20) which has been kept at room tempera- 

 ture for two days. 



Tube 3: 1 c.c. of guinea-pig serum (1:20) three days old. 



Tube 4: 1 c.c. of guinea-pig serum (1:20) five days old. 



Add 1 c.c. of a 2^ per cent, suspension of sheep corpuscles, two hemolytic units 

 of antisheep amboceptor, and sufficient normal salt solution to each tube. Shake 

 gently and incubate at 37 C. for one hour. 



4. Into a series of six test-tubes place 1 c.c. of fresh guinea-pig complement serum 

 diluted 1 : 20. Place these in a water-bath at 56 C. At intervals of ten, twenty, 

 thirty, forty, fifty, and sixty minutes remove a tube, add 1 c.c. corpuscle suspension, 

 two units of amboceptor, and sufficient salt solution. Shake gently each tube and 

 incubate for one hour at 37 C. 



(a) Record the results. Does hemolytic complement deteriorate 

 readily at room temperature? 



(b) What are complementoids? 



(c) What practical significance has this experiment? Should a 

 complement serum be fresh when used in hemolytic work? 



(d) Is complement thermolabile? How long does it take to destroy 

 a diluted complement at 56 C.? 



(e) In inactivating a serum why do we not use a higher temperature? 



