Antigen Removed from Circulation. 



269 



117 (1864) 



On the mechanism by which antigen is removed 

 from the circulation. 



By GEORGE M. MACKENZIE and EMILY L. FRUHBATJER. 



[From the Department of Medicine, College of Physicians and 

 Surgeons, Columbia University and the Presbyterian Hospital, 

 New York City.] 



In studying the rate of disappearance of horse serum and the 

 curves for circulating precipitin in a group of serum-treated 

 patients it was noted that individuals who have severe serum 

 disease are good precipitin formers and that at the time the 

 precipitin in the circulation reaches the crest of its curve or soon 

 thereafter the precipitinogen rapidly disappears from the blood 

 stream. On the other hand in those individuals who after a 

 first administration of foreign serum, show very mild or no 

 symptoms of serum disease little or no precipitin is demonstrable 

 in the patient's serum and the precipitinogen persists in the circula- 

 tion for a long period. Intermediate types were also encountered. 

 From these results it seemed at least plausible to assume that an 

 important factor in determining the rate of disappearance of the 

 foreign serum from the circulation was an intravascular union of 

 antibody and antigen. That such an assumption is erroneous 

 seems probable from the following experiments : 



In one series of experiments 12 previously immunized rabbits 

 were injected intravenously with amounts of horse serum (3.00 

 c.c. or 6.00 c.c.) comparable to the amounts used therapeutically 

 in the group of patients studied. The animals were then bled 

 every second or every third day and the precipitin and precipi- 

 tinogen in the serum titrated. Six of the animals had a high 

 titer (1:20,000 or higher) of precipitin in the circulation at the 

 time of reinjection, 2 had a moderately high titer, I had only 

 traces of precipitin, and 3 had no circulating precipitin. Two of 

 the 3 rabbits with no circulating precipitin had been immunized 10 

 months previously and at that time had developed a high titer of 

 precipitin which had entirely disappeared before the reinjection. 

 Presumably such previously immunized rabbits which had shown 



