IMMUNOLOGICAL BEHAVIOR 12^ 



amount oi anti-complementary factors was foinid in sera devoid 

 of the atixiliary factor as well as in sera containing large amounts 

 of it. 



The auxiliary factor described seemed to be in the nattne of 

 an antibody, the production of which is stimtdated by immuniza- 

 tion ^vith B. colt heated cultures and cultine filtrates. 



The antibody appears shortly after the beginning of immiuiiza- 

 tion. The length of time necessary, ho^vever, for its development 

 differs in horses tnider the same treatment. Thtis, after ten ^veeks 

 of immiuiization the antibody ^vas absent in one horse but pres- 

 ent in another. The majority of horses developed the antibody in 

 eight to ten Aveeks. The antibody also disappeared in t^vo horses 

 during the process of immiuiization. After the disappearance of 

 antibody, the horses rested intermittently for nine Aveeks. Three 

 weeks of immiuiization folio-wing the last period of three ^veeks 

 rest again stimulated the production of the antibody. 



The auxiliary antibody ^vas absent from a series of normal 

 horse sera and \arious other heterologous sera (scarlet fever anti- 

 toxin, anti-typhoid horse serum, tetanus antitoxin. Type I pneu- 

 mococcus antibody, human convalescent pneumonia sera, and 

 Type II pneumococcus antibody). (Shwartzman, 1931/-'.) 



REACTIVATING EFFECT OF BLOOD SERA UPON COMPLETELY 

 NEUTRALIZED TOXIC FILTRATES 



Following observations on the heterologous antibody auxiliary 

 to neutralization of meningococcus reacting factors, it seemed of 

 interest to determine \vhether blood sera also contained factors 

 having the opposite effect; that is to say, capable of reactivating 

 completely neutralized toxic filtrates. 



In these experiments rabbits Avere injected intradermally Avith 

 0.5 c.c. of undiluted meningococcus Group III "agar washings" 

 filtrate. The sera tested for the reactivating property were injected 

 intravenously t^venty-three and one-half hours later. This Avas 

 followed by the intravenous injection of the completely neutral- 

 ized meningococcus preparation one-half hour later. The menin- 

 gococcus preparation ^vas a meningococcus Group III "agar ^vasli- 

 ings" filtrate. The completely neutralized mixtures consisted of 

 one part of the filtrate containing in each 1 c.c. the necessary 

 number of toxic units, 0.9 part of anti-meningococcus horse 

 serum, and 0.1 part of auxiliary antibody. The mixture ^vas in- 



