250 



BIOLOGY OF PNEUMOCOCCUS 



from the review 605 which has been drawn upon so freely in the pres- 

 ent discussion.* 



PNEUMOCOCCUS AND CELL CONSTITUENTS 



ANTIBODIES DEMONSTRABLE IN SERUM 



Material used for immunization 



Intact cells (SP)t 



Carbohydrate S+ 



Protein P§ 



Solutions, extracts containing free 

 S and free P 



Suspension of intact cells and dis- 

 sociated cell constituents (SP), 

 free S, free P 



Effective 

 antigen 



(SP) 



None 



P 



(SP), P 



+ 



+ 



Pre- 

 cipitins 



+ 



+ 



Comple- 

 ment 

 fixation 



+ 



+ 



Speci- 

 ficity 



+ 



+ 



+ 

 + 



+ 



* = Free S, as antigen, does not fix complement with immune horse serum; 



is active with immune rabbit serum. 



t (SP) = Carbohydrate and protein, combined antigen of cell. 



X S = Free carbohydrate, the soluble specific substance of cell. 



§ P = Free protein of cell. 



Heidelberger continued : 



It was evident that morphological dissolution of pneumococci is ac- 

 companied by antigenic dissociation, for sera prepared from filtered so- 

 lutions of disintegrated cells free of formed elements fail to exhibit any 

 of the dominant type-specific properties which characterize sera ob- 

 tained by immunization with whole bacteria. The injection of suspen- 

 sions of pneumococci into animals induces the formation of antibodies 

 against S [carbohydrate] alone or against both S and P [protein] 

 separately, depending upon whether or not these suspensions contain 

 only intact cells or a mixture of both intact and dissolved cell bodies. 

 Since pneumococci readily undergo autolysis and dissolution, suspen- 

 sions and broth cultures of these organisms almost invariably contain 

 not only formed elements, but also more or less of dissociated cell con- 

 stituents in solution. Therefore, use of suspensions of pneumococci con- 



* Many of the experimental data from which the table was compiled are to 

 be found in the original papers by Avery and Heidelberger; Heidelberger and 

 Goebel; Heidelberger, Goebel, and Avery; Heidelberger and Avery; Avery, 

 Heidelberger, and Goebel; Avery and Morgan; and Avery and Neill. 



