BACTERIAL COMPLEMENT FIXATION TECHNIQUE 403 



horse. It is used to some extent as an aid in the diagnosis of tuber- 

 culosis, but in general the tuberculin reaction has been found much 

 more satisfactory. The agglutination reaction rather than comple- 

 ment fixation is used almost exclusively in the identification of 

 unknown organisms and in the diagnosis of typhoid fever, un- 

 dulant fever and tularemia. The complement fixation technique 

 has found its greatest application as an aid in the diagnosis of 

 syphilis. This will be discussed in Chapter XXIII. More recently 

 Craig (1927, 1928, 1929, 1930) and Sherwood and Heathman 

 (1932) have studied its use in amebic dysentery cases and carriers. 

 Dulaney's* (1940, 1941) work suggests that the test may be of 

 value in malaria; Lennette and Horsfall (1941) have employed 

 complement fixation in their influenza work and Witebsky, Wels 

 and Heide (1941) report that the complement fixation test is 

 sui)erior to the precipitin test in trichino.sis. 



Reagents and Factors Involved. — A study of the protocol illus- 

 trating the technique employed by Bordet and Gengou shows that 

 the following seven reagents were used ; namely — complement, bac- 

 terial antigen, bacterial antibody, normal serum, red blood cells, 

 hemolytic amboceptor and physiological saline. It also involves 

 certain arbitrary expressions of total volume in each tube, time, 

 temperature and conditions of incubation as well as the use of 

 test tubes and pipettes. 



Development of Modern Technique. — Modern complement fixa- 

 tion is a result of intensive and extensive studies of each of these 

 factors with a view toward obtaining greater accuracy, simplicity, 

 and standardization of procedure. Its evolutionary development 

 may be traced through the following progressive steps : 



1. The introduction of a complement fixation technique by 

 Bordet and Gengou in 1901. Their technique defined a unit of 

 red cells (rabbit), specified physiological saline as a diluent, a 

 primary incubation of 15 to 18 hours at 20° C, and a secondary 

 incubation of one hour at 37° C. They apparently did not em- 

 ploy a uniform total volume nor did they recommend a method 

 of titrating amboceptor, complement, or antigen. 



2. Ehrlieh, V. Dungern, Wassermann, Bruck and others intro- 

 duced a standard total volume (Von Dungern preferred 2.0 c.c, 

 Wassermann and Bruck 5.0 c.c.) aiid substituted sheep for rabbit 



*Dulaney, A. D.. and Stratman-Thomas, W. K. : Complempnt-Fixation in 

 Malaria, J. Immunol. 39: 247, 257. 1940. 



