HYPERSENSITIVENESS 52§ 



animal or experimental conditions described by McJunkin and 

 confirmed by Zinsser. McJunkin injected tubercle bacilli in- 

 to the peritoneal cavity of infected guinea pigs and 24 hours 

 later removed the peritoneal exudate, filtered and injected 

 it into normal guinea pigs. A number of these normal recipients 

 showed tuberculin hypersensitiveness when tested six or eight days 

 later. Baldwin (1910) and Zinsser (1931) suggest that per- 

 haps the train of events leading to the allergic state in tu])erculosis 

 may be described somewhat as follows : 



First tlie tubercle bacillus lodges in the tissues and the ])ody 

 reacts to its presence by the formation of a tubercle. The action 

 of the inflammatory tissue ui)on the bacteria, probably by means 

 of enzymes, causes the liberation of an antigenic substance which 

 is responsible for tuberculin allergy. It is only recently that 

 one has been able to extract from the tubercle bacillus such an 

 antigenic substance and no one has been able to prove that anti- 

 bodies are involved. It is interesting to note that while tuber- 

 culin OT is devoid of skin sensitizing power, such tuberculins as 

 MA-100 and TPT possess it. At first Seibert believed that OT 

 and likewise PPD were not antigenic because of their small 

 molecular weights and conversely MA-100 and TPT were antigenic 

 be<^ause of their large molecular weight. Subsequent work has 

 led Seibert (1941) to alter her views. She is now inclined to 

 think that potency is inherent in one part of the tuberculin pro- 

 tein molecule while antigenicity is dependent upon another part 

 of the same molecule. Apparently the work of Landsteiner (1935) 

 (1938-1940), as well as the work of StuU and Hampton (1941), 

 indicates that less complex substances than complete proteins can 

 function as antigens. StuU and Hampton report that certain 

 proteoses obtained from Witte's peptone are antigenic. It is pos- 

 sible, as suggested by the work of Landsteiner, that these sub- 

 stances function as haptens and unite with body proteins to form 

 complete antigens. Seibert 's work suggests that tuberculin may 

 function as a hapten when it is antigenic. 



A somewhat similar state of affairs exists in undulant fever. 

 Fleischner, Meyer and Shaw (1919) as well as others have shown 

 lluit while guinea pigs can be rendered anaphylactic by injecting 

 suspensions of Brucella abortus and melitensis, skin sensitiveness 

 does not develop unless active infection is present. 



