852 EXPERIMENTAL INFECTION AND IMMUNITY 



2. In a second centrifuge tube place 2 c.c. of diluted complement and 2 c.c. cor- 

 puscle suspension. Keep at room temperature for one hour, centrifuge, and pipet the 

 supernatant fluid into a test-tube. 



3. Proceed as follows: To 2 c.c. of the supernatant fluid from the first centrifuge 

 tube add 1 c.c. corpuscle suspension; to the remaining 2 c.c. add 1 c.c. corpuscle sus- 

 pension and two units of amboceptor; to the sedimented corpuscles add 2 c.c. of 

 diluted complement serum. 



4. To 2 c.c. of the supernatant fluid from the second centrifuge tube add 1 c.c. 

 corpuscle suspension; to the remaining 2 c.c. add 1 c.c. corpuscle suspension and two 

 units of hemolytic amboceptor. 



5. To the sedimented corpuscles in both centrifuge tubes add 1 c.c. complement 

 serum and 1 c.c. salt solution. Mix well. 



6. Shake all tubes gently and incubate for one hour at 37 C. 



(a) In which tubes has hemolysis occurred? 



(b) Does complement unite directly with corpuscles? 



(c) What evidence have you that amboceptors unite directly with 

 corpuscles? 



(d) What is meant by the term "sensitizing corpuscles"? 



(e) Is complement-amboceptor activity apparent at low temperature? 



(f) What temperature best favors complement-amboceptor activity? 



EXERCISE 31. AMBOCEPTORS AND COMPLEMENTS. HEMOLYSINS 



(Continued) 



EXPERIMENT 79. NATURAL HEMOLYSINS. REMOVAL OF NATURAL 

 HEMOLYSINS 



1. Secure 1 c.c. of serum from the blood of five different persons and inactivate 

 in the water-bath. 



2. Remove 0.5 c.c. of serum from each to five separate centrifuge tubes and add 

 4.5 c.c. of ly^ per cent, suspension of sheep cells to each. Shake gently and after 

 half an hour at room temperature centrifuge thoroughly and pipet the supernatant 

 dilute serum to separate tubes. Do not discard the corpuscles in the centrifuge 

 tubes. 



3. To each of the remaining 0.5 c.c. amounts of serum add 4.5 c.c. salt solution 

 and place 1 c.c. and 2 c.c. into two test-tubes respectively (0.1 c.c. and 0.2 c.c. undi- 

 luted serum). 



4. Into two more test-tubes place 1 and 2 c.c. respectively of the diluted serum 

 which has been treated with corpuscles. 



5. Add to each tube 1 c.c. of guinea-pig complement (1:20), 1 c.c. of 23/ per 

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

 bate for one hour. 



6. To the sedimented corpuscles in the centrifuge tubes add 2 c.c. of diluted com- 

 plement serum and sufficient salt solution. Shake gently and incubate for one hour. 



(a) Has hemolysis occurred with the untreated serums? 



(b) How do you explain the results? 



(c) Has hemolysis occurred with the treated serums and if not, why 

 not? 



