926 EXPERIMENTAL INFECTION AND IMMUNITY 



3. In a second series of four test-tubes place one-half an amboceptor unit and the 

 following amounts of diluted complement serum: 1 c.c., 2 c.c., 3 c.c., and 4 c.c. Add 



1 c.c. of the suspension of sheep corpuscles and sufficient salt solution to make the 

 total volume in each tube about equal. Incubate for one hour and read the results. 



4. In a third series of four test-tubes place one amboceptor unit, 1 c.c. of com- 

 plement serum (1:20), and the following amounts of corpuscle suspension: 1 c.c., 



2 c.c., 3 c.c., and 4 c.c. Add sufficient salt solution to make the total volume in each 

 tube about equal. 



5. Prepare a corpuscle control with 1 c.c. of suspension and 4 c.c. normal salt 

 solution. 



6. Shake all tubes gently and incubate for two hours at 37 C. 



(a) Can an excess of amboceptor make up for a deficiency in comple- 

 ment? 



(b) Can an excess of complement make up for a deficiency of ambo- 

 ceptor? 



(c) What happens when an excess of corpuscle suspension is used? 



(d) Discuss the importance of quantitative factors in serum hem- 

 olysis. 



EXERCISE 29. AMBOCEPTORS AND COMPLEMENTS (Continued) 



EXPERIMENT 75. R6LE OF AMBOCEPTOR AND COMPLEMENT IN HEM- 

 OLYSIS 



1. Prepare a 23/ per cent, suspension of washed sheep corpuscles. Bleed a 

 healthy guinea-pig under ether anesthesia, separate the serum, and dilute 1:20 with 

 normal salt solution (complement). Secure antisheep hemolytic serum (inactivated) 

 whose hemolytic titer is known (consult instructor). 



2. Proceed to set up a series of four test-tubes as follows: 



Tube 1: 1 c.c. corpuscle suspension + sufficient normal salt solution to make the 



total volume about 3 c.c. 

 Tube 2: 1 c.c. corpuscle suspension+1 c.c. complement serum (1 : 20) +sufficient 



salt solution. 

 Tube 3: 1 c.c. corpuscle suspension -j- two hemolytic doses of antisheep hemolysin 



+ salt solution. 

 Tube 4: 1 c.c. corpuscle suspension+1 c.c. complement serum+two doses of 



hemoly sin + salt solution. 



3. Shake each tube gently and incubate at 37 C. for one or two hours. 



(a) In which tube has hemolysis occurred? Explain the results. 



(b) What does inactivation of a serum mean? 



(c) Could some hemolysis occur, using the complement serum and 

 corpuscles without immune hemolysin? 



EXPERIMENT 76. SPECIFICITY OF AMBOCEPTORS 



1. Prepare a 2^ per cent, suspension of washed sheep corpuscles and a 1 per 

 cent, suspension of washed human corpuscles. Bleed a guinea-pig under ether, 



