CHAPTER VIII 

 COMPLEMENT FIXATION 



INTRODUCTION. 



THE BORDET-GENGOU PHENOMENON. 

 LABORATORY DEMONSTRATION. 



ANTI-COMPLEMENTARY AND HEMOLYTIC TITER OF ANTIGEN. 

 THE TEST. 



SPECIFIC CHARACTER OF THE TEST. 

 INHIBITION ZONES. 

 GROUP REACTIONS. 



RELATION OF COMPLEMENT-FIXING BODIES TO OTHER IMMUNE BODIES. 

 IS THE COMPLEMENT-FIXING BODY AN AMBOCEPTOR ? 

 ACTIVATION BY COMPLEMENT. 



FIXATION OF THE COMPLEMENT OF NATURAL HEMOLYSINS. 

 INHIBITION OF COMPLEMENT OTHER THAN BY FIXATION. 

 ANTI-COMPLEMENTARY CHEMICAL AGENCIES. 



ANTI-COMPLEMENTARY ACTION OF CELLS, TISSUE EXTRACTS AND BODY FLUIDS. 

 ANTI-COMPLEMENTARY ACTIVITY OF IMMUNE SERA. 



Introduction. A summary of the hypotheses concerning the con- 

 stitution of complements shows that there are three important views 

 offered, namely the " pluralistic " conception of Ehrlich and Morgen- 

 roth, the " dualistic " of Metchnikoff and " unitaristic " of Bordet. 

 As has been explained, the view of Metchnikoff that complement might 

 be a " macrocytase " or a " microcytase " depending upon its cellular 

 origin has been abandoned by most immunologists. Thus the conflict 

 has been, and in certain measure still is, between the views of Ehrlich 

 and of Bordet. Bordet and Gengou in demonstrating that the same 

 complement is called on for bacteriolysis as for hemolysis, discovered 

 the phenomenon named by them complement fixation (" la fixation 

 d'alexine ") which we employ in sharp contradistinction to complement 

 deviation. The latter term implies the anchoring of complement by 

 free amboceptor units, whereas fixation signifies the entrance of the 

 complement into combination with antigen and amboceptor. In brief, 

 they showed that if complement is utilized in the process of bacteriolysis 

 it is not available for hemolysis. 



The Bordet-Gengou Phenomenon.-^The primary experiment was 

 performed with plague bacilli, the serum of a horse immunized to 

 plague bacilli, fresh guinea-pig serum (complement) and sensitized red 

 blood-corpuscles, i.e., corpuscles saturated with a specific hemolytic 

 immune serum. They mixed an emulsion of plague bacilli, the anti- 

 plague horse serum and complement. This mixture was left at room 

 temperature for five hours and then the previously-sensitized erythro- 

 cytes added, the mixture incubated and observed. No hemolysis 

 appeared, although the corpuscles were often agglutinated by the hemo- 

 lytic (and hemagglutinative) immune serum. Naturally, such an ex- 



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