28 LABORATORY COURSE IN SERUM STUDY 



Then, as in the preceding case, we have two tubes to which the 

 following additions are made : 



Tube 1 Tube 2 



(Supernatant fluid from (Sediment from Tube B 



Tube B) about . . . 2.0 c.c. resuspended in salt 



Immune rabbit serum 1.0 c.c. solution) 3.0 c.c. 



Sheep cells 5% . . 1.0 c.c. Immune rabbit serum . 1.0 c.c. 



Incubate and observe. 



In which tube does haemolysis take place? Contrast this with 

 results in Tube A and draw conclusions. 



Experiment 2 



TO SHOW THAT AT C. CELLS WILL ABSORB AMBOCEPTOR ALONE 

 FROM A MIXTURE OF AMBOCEPTOR AND COMPLEMENT 



The same reagents will be used in this as in the preceding experi- 

 ment. The three reagents will first be cooled in ice water and then be 

 mixed in a cold centrifuge tube, and allowed to stand at C. for an 

 hour. With proper care this can easily be done in a battery jar filled 

 with cracked ice and brine. 



The success of the experiment depends on having the reagents and 

 the centrifuge tube and metal holder thoroughly cooled in ice water 

 before the mixture is made and in centrifugalizing and removing the 

 supernatant fluid before they have time to regain the temperature of 

 the room. The protocol for this experiment is given below : 



Place centrifuge tube in holder in a cup of cracked ice and water and 

 add: 



5% sheep cells 1.0 c.c. 



Inactive immune rabbit serum (diluted) . . 1.0 c.c. 

 Guinea pig serum (1-10) 1.0 c.c. 



After twenty minutes the tube is centrifugalized, the supernatant 

 fluid removed and half of it placed in each of two small test tubes. 

 The sediment is to be washed once in cold salt solution, resuspended 

 in 4 c.c. of salt solution and half of this suspension placed in each of 

 two small test tubes. 



We now have four tubes two of which contain washed sediment 

 and two of which contain supernatant fluid of the original mixture. 

 To these the following additions are now made : 



