106 LOCAL TLSSUE REACTIVITY 



Structure, as avcII as ol hi<>li autioeuicity. The reacting factors of 

 the remaining stock strains may represent various degrees of in- 

 creasing antigenic complexity, the Ty 159 stock strain being the 

 most complex one. The additional complicating components, 

 however, have to be considered of low antigenicity, as is seen 

 from the fact that ]:)olyvalent sera, in the preparation of ^vhich 

 there was included Ty 159 stock strain, and certain homologous 

 monovalent rabbit sera, fail to give a high degree of neutralization 

 Avith these factors. Finther proof of this contention is brought out 

 by the following work ^vith "mouse" strains: 



The passage of B. h'ljJiosus stock strains through mice may or 

 may not affect the neutralizability of their reacting factors. In 

 one strain Avhich ^vas considered above as the simplest in the 

 antigenic structure of its reacting factors (Ty Tl stock) there oc- 

 curred a partial loss of neutralizability (Ty Tl Mouse,-,^ and Sera 

 Sr, and S(;) . This fact may be interpreted as an acc|uirement of 

 additional components. The factors of another strain considered 

 as the most complex ones (Ty 159 stock strain) showed no 

 change in the neutralizability of the reacting factors after 46 

 passages through mice. However, there occiuTed an increase in 

 the antigenicity of the factors of this strain. This fact is ^vell 

 illustrated by the experiments ^^ ith R-^^09 serinn homologous for 

 Ty 159 Mouse^r; strain ^vhich shoAvs a high degree of consistent 

 neutralization ^vith the reacting factors of the latter. 



The passage of a strain through mice is not necessarily accom- 

 panied by an increase in the antigenicity of the factors of lo^v 

 neutralizability. The Ty 240 stock strain ^vhich showed factors of 

 low neutralizability was tested with anti-Ty Tl stock serum (S5) 

 as ^vell as with an anti-mouse-passed-Ty 250-strain serum (Sr,) 

 (previous unrecorded experiments) . Both sera showed low neu- 

 tralizations ^vith the reacting factors of the mouse strain. 



As is also seen from Diagrams 1 and 2 there occurs an almost 

 complete loss of neutralizability of reacting factors of the rough 

 variants by the anti-stock sera. The change is illustrated by 

 numerous experiments (Ty Tl 2^^8 ser.o and Ty Tl 245 ser.j, Ty 

 870 phages vs. Sera S-,, So, Horses » , and 15 ). The loss of 

 neutralizability is associated Avith acquisition of a ne^v antigenic 

 specificity. The "rough" reacting factors are consistently neutral- 

 ized by homologous sera and by polyvalent sera, in the prepara- 

 tion of which there were included the rough variants (Serum S3 



