46 LABORATORY COURSE IN SERUM STUDY 



LESSON VI 



THE UNION OF IMMUNE-BODY (AMBOCEPTOR OR SENSI- 

 TIZER) AND CELLS 



1. DISSOCIATION OF AMBOCEPTOR (Mum) 



RED cells have a very great affinity for their specific immune- 

 body. They can absorb a great number of units. Nevertheless at 

 37 C. corpuscles containing multiple doses of amboceptor give off 

 a certain amount to the surrounding fluid when it is free of it. 

 There appears to be an equilibrium between combined and free im- 

 mune-body. This can be illustrated by the following experiment : 



To 1.5 c.c. of a 5 per cent emulsion of sheep corpuscles is added 

 inactivated haemolytic serum so that there shall be 20 units of ambo- 

 ceptor l to every 0.5 c.c. of cells. (The student should calculate and 

 make dilutions for this purpose after being told the unit of the hsemolytic 

 serum given him.) 



This mixture is allowed to stand at room temperature for 30 minutes. 



Centrifugalize and set aside the supernatant fluid. This is Tube (a). 



Wash the cells obtained in the sediment of the preceding centrifuga- 

 tion three times and set aside the salt solution remaining as supernatant 

 fluid of the last washing. This is Tube (6) . 



Make the suspension of red cells up to the original volume by the 

 addition of saline and incubate this at 37 C. for one hour. Then centrif- 

 ugalize and set aside the supernatant fluid of this, which constitutes 

 Tube (c). 



Make the sediment of the cells obtained in the preceding up to 1.5 

 c.c. Shake. Remove 0.5 c.c. and add to it 1.0 c.c. of 10 per cent fresh 

 guinea pig complement. This is Tube (d). 



To (a), (6) and (c), each, add 0.5 c.c. of 5 per cent sheep corpuscles 

 and 1.0 c.c. of complement (10 per cent fresh guinea pig serum in salt 

 solution). 



All four tubes are incubated at 37 C. for one hour. 



Record the degree of laking in each tube. 



Tube (a) will show how much of the 20 units of amboceptor failed to 

 be absorbed. The exact amount could be determined by titration, which, 

 however, would needlessly prolong the experiment and add nothing 

 to the illustration of the principle. 



1 The unit here is the minimal amount which lakes 0.5 c.c., not 1 c.c., of cells. 

 If Experiments 1 and 3 of this lesson are to be done on the same afternoon it is 

 well to sensitize a considerable amount of cells at one time. 



