STUDIES ON TRANSPLANTATION ANTIGENS 9 



Table I 



Effect of electrolytes on solubility of antigenic matter prepared by 

 ultrasonic dispersion of a-strain lymphoid cells in water 



All experiments A-^CBA except 201 and 287 (CBA->A). Sensitivity of recipients 

 measured by degree of epithelial survival in A-strain body skin grafts removed 

 6 days after transplantation. Dose per mouse expressed in terms of original wet 

 wt. in mg. of lymphoid tissue from which the antigen was extracted. Sec, u/s 

 = time of exposure to ultrasound, in seconds. 



[A] Original crude aqueous preparation before addition of electrolyte : roughly 

 equal subdivision of activity between sediment and supernatant after spinning 

 30 to 45 min. at 27,700^ (max). 



Sec. Spin^ 

 Expt. Dose u/s min. Scores: supernatant Scores: sediment 



217 260 60 45 50,25,10,0 25,10,0,0 



287 290 45 30 50,25,10,10,10 50,25,10,0,0 



319 380 60 30 25,25,25,10,5 75,50,25,25,10 



[B] Supernatant resulting from procedure [A]: retention of perceptible fraction of 

 sensitizing power by supernatant after further centrifugation at high speeds. 



Sec. Spin, Supernatant: Sediment: 



[C] Supernatant resulting from procedure [A]: after addition of NaCl to o-i5M 

 the greater part of the activity appears in the sediment produced by a further 

 centrifugation at 27,700^ for 30 min. Ultrasound: 30 sec. exposure throughout. 



Scores: supernatant Scores: sediment 



50,50,25,25,5 50,10,10,0,0 



75,50,50,25,5 10,5,5,0,0 



75, 50, 50, 50, 25, 25, 5, o 25, o, o, o, o, o, o, o 



[D] Partition of activity between sediment and supernatant fluid when MgCla 

 or CaCl2 (O'OIM final cone.) is added to crude aqueous antigen, followed by 

 centrifugation at '>-'2500^ for 10 min. 



