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 2^ 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 + two hemolytic doses of antisheep hemolysin 



+ salt solution. 

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



hemolysin + 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 2J^ per cent, suspension of washed sheep corpuscles and a 1 per 

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



