Bence-Jones Proteins. 



221 



Studies were made upon 13 preparations of Bence-Jones pro- 

 tein from various sources and prepared in various ways. Com- 

 parative studies of these preparations and of human serum were 

 carried out by the use of precipitin, complement fixation and 

 anaphylactic reactions. 



Precipitin Reactions. — Rabbits were injected intravenously 

 with solutions of the crystalline Bence-Jones protein, an ammoni- 

 um-sulphate preparation of a non-crystallizable specimen of this 

 protein from another source, and with human serum. After im- 

 munization, the serum of these animals contained precipitins which 

 flocculated the homologous antigens in high dilutions. In the 

 series of comparative precipitation tests, all the solutions of 

 Bence-Jones proteins were used in a concentration of 4 per cent., 

 and from this dilutions were made. The hydrogen-ion concentra- 

 tion of the fluids and the environmental conditions were uniform. 

 Readings of precipitation were made by the ring tests after 1 hour 

 at room temperature, and again after 24 hours at 37 0 C. The 

 antiserum to the crystalline Bence-Jones protein precipitated a I 

 to 1,000,000 dilution of a 4 per cent, solution of this preparation, 

 affected only slightly or not at all the other preparations from 

 other sources, and gave no trace of precipitate with human serum. 

 By the use of this purified preparation of Bence-Jones protein, 

 therefore, it was possible to show at once that there are differences 

 between various Bence-Jones proteins as regards their precipit- 

 ability by an antiserum to one substance of this class, and that 

 there is a sharp immunological distinction between Bence-Jones 

 protein and human serum. Corroboration of these findings came 

 next through the use of the antiserum to the non-crystallizable 

 Bence-Jones protein. This serum did not precipitate the crystal- 

 line Bence-Jones protein, variously affected the solutions of the 

 other preparations, and gave a precipitate with human serum at I 

 to 1000. Antihuman serum did not precipitate the solution of the 

 crystalline Bence-Jones protein, but gave precipitates with the 

 urines of several patients with Bence-Jones proteinuria, and 

 with all of the salted-out preparations of Bence-Jones protein. 



Complement Fixation Reactions. — The usual antisheep ambo- 

 ceptor system with guinea pig complement was used and all con- 

 trols were made with quantities of solutions double those used in 



