174 Scientific Proceedings (114). 



85 (1667) 



Antipneumococcus protective substances in normal chicken serum. 



By CARROLL G. BULL and CLARA MCKEE. 



[From the Department of Immunology, School of Hygiene and Public 

 Health, the Johns Hopkins University, Baltimore.] 



The serum of the domestic fowl has been found to protect 

 mice and guinea pigs against infection with the pneumococcus. 

 The protective power of the serum was demonstrated by giving 

 mice, intraperitoneally, 1 c.c. of the serum and giving the infecting 

 culture by the same route four to six hours later. The following 

 protocol illustrates the plan of the experiment and the results 

 obtained. 



PROTOCOL. 



Mouse Protection against Type I Pneumococcus with Normal Chicken 



Serum. 



Mice. 



Serum. 



Type I Pneumococcus. 



Results. 



1 



1 C.C. 



0.01 c.c. 



D. 48 hrs. 



2. 



1 C.C. 



0.001 c.c. 



S. 5 days 



3 



1 C.C. 



0.0001 c.c. 



S. 5 days 



4 



1 C.C 



0.00001 c.c. 



S. 5 days 



5, 



1 C.C. 



0.000001 c.c. 



S. 5 days 



6 





0.0000001 c.c. 



D. 36 hrs. 



D., dead; S., survived 5 days and discarded. 



Further experiments showed that the serum protects against 

 all serologic types of pneumococci and that there is a particular 

 protective substance for each type. Thus, serum adsorbed with 

 Type I organisms no longer protects against this type but protects 

 against Type II cultures as well as before the adsorption and vice 

 versa. This relation exists between all of the types. 



A peculiar relationship was found to exist between Type II 

 strains and the subtypes of this group. Thus, serum adsorbed 

 with Type II organisms failed to protect against Type II culture 

 but still protected against the cultures of Types II A and II B. 

 Serum adsorbed with Type 11^4 organisms loses its protective 

 power for II A and II cultures but not for II B cultures. Also, 

 serum adsorbed with \\ B organisms no longer protects against 



