560 BIOLOGY OF PNEUMOCOCCUS 



(1924). 1553 Felton 398 observed that, in general, agents that cause 

 denaturation of the globulins in antipneumococcic serum also re- 

 sult in a destruction of protective antibody. The addition of acids, 

 alkalies, and preservatives — particularly chloroform, which co- 

 agulates the water-insoluble globulin — repeated solution in hydro- 

 chloric acid and precipitation by sodium hydroxide, or frequent 

 solution in sodium chloride and precipitation by water at room 

 temperature were all observed by Felton to result in a modification 

 of the immune globulin. 



Felton 403 also stated that serums which were stored for a long 

 period of time, with or without preservative, undergo denatura- 

 tion and, in describing the sodium sulfate method of concentration, 

 listed three common causes which may be controlled, namely, bac- 

 terial contamination, maintenance of serum or precipitate at too 

 high a temperature in acid or alkaline solution, and too high a 

 concentration of preservative. Excessive heat also alters the solu- 

 bility of the protective globulin in antipneumococcic serum (Fel- 

 ton 397 ). Impurities and the hydrogen ion concentration of agents 

 used as precipitants in the concentration process may also con- 

 tribute to the change in the protein. In the report on the use of 

 sodium sulfate, Felton emphasized the point that the salt may be 

 markedly alkaline and require neutralization prior to use. Serum 

 concentrated by ammonium sulfate, although satisfactory in many 

 ways, frequently elicits a high incidence of thermal reactions, pos- 

 sibly due in part to changes in the serum protein. Observations by 

 Cianciarulo (1935)* on the hydrogen ion concentration of am- 

 monium sulfate offer a possible explanation for alterations in pro- 

 tein antibody when purified by means of the ammonium salt. The 

 reaction of some lots of the sulfate was found to be as acid as pH 

 4.4 and, when used in concentrating diphtheria antitoxin, resulted 

 in marked denaturation as evidenced by the formation of an in- 

 soluble, jelly-like precipitate. The salt, with the reaction properly 

 adjusted, no longer caused this effect. 



* Unpublished. 



