AMBOCEPTORS AND COMPLEMENTS 855 



EXPERIMENT 84. PHENOMENON OF COMPLEMENT FIXATION 



This experiment is introduced here to show the Bordet-Gengou 

 phenomenon of complement fixation. The exact technic of complement- 

 fixation reactions as conducted for the diagnosis of syphilis and other 

 infections will be given in subsequent exercises. 



1. Use the same complement serum, "amboceptor and corpuscle suspension as 

 used in the preceding experiment. The unit of complement is now known. 



2. Secure 1 c.c. of an antigonococcus and a normal serum and heat at 56 C. for 

 thirty minutes. 



3. Secure an emulsion of gonococci which is now called the antigen; for the proper 

 dose to use consult the instructor. 



4. Proceed as follows: 



Tube 1 : 0.2 c.c. antigonococcus serum + dose of antigen + 2 units of comple- 

 ment + normal salt solution. 

 Tube 2: 0.2 c.c. antigonococcus serum + 2 units of complement + normal salt 



solution (serum control). 

 Tube 3: 0.2 c.c. normal serum + doses of antigen + 2 units of complement + 



normal salt solution. 

 Tube 4: 0.2 c.c. normal serum + 2 units of complement + normal salt solution 



(serum control). 



Tube 5 : dose of antigen + 2 units of complement + normal salt solution (anti- 

 gen control). 



Tube 6: 2 units of complement -f normal salt solution (hemolytic control). 

 Tube 7: 1 c.c. corpuscle suspension + normal salt solution (corpuscle control). 

 Plug tube with cotton as it is finished. 



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



6. Add \Y^ units of amboceptor and 1 c.c. corpuscle suspension to all tubes 

 except corpuscle control. Shake gently and reincubate for one hour. 



(a) Examine tubes and record your results. 



(b) Why was the serum control on each serum necessary? 



(c) Why was the hemolytic system control necessary? 



(d) Why was the antigen control necessary? 



(e) What is meant by non-specific complement fixation? 



(f) What is meant by specific complement fixation? Explain the 

 phenomenon. Which tube of this series shows specific complement fixa- 

 tion and why? Is there any evidence of non-specific fixation in any of 

 the tubes? If so, what bearing would this have on the results of this 

 test? 



(g) What is meant by complement deviation? 



(h) Upon what does the specificity of complement fixation depend? 



