ANTI-ANAPHYLAXIS OR DESENSITIZATION 599 



anchoring of the anaphylactic antibody to the body-cells, and, according 

 to Weil, sufficient time must always elapse after the injection of serum 

 for this union to occur. 



ANTI-ANAPHYLAXIS OR DESENSITIZATION 



The term anti-anaphylaxis was first applied by Besredka and Stein- 

 hardt to a condition of insensibility to further injection of the anaphylac- 

 togen that may follow recovery from anaphylaxis, or be induced arti- 

 ficially by a single or by repeated small injections of the anaphylactogeh 

 during the incubation period following the first injection, and before 

 sensitization is completed. The state is usually only temporary, the 

 animal gradually becomes sensitive again after three weeks. 



Theobald Smith had observed that those guinea-pigs that had re- 

 ceived the largest dose of diphtheria toxin-antitoxin mixture more 

 frequently survived the second dose than did those that received smaller 

 doses. Rosenau and Anderson found that animals reinjected before 

 the end of the period of incubation did not become responsive until 

 some time later. Otto has also made this observation, but the most 

 thorough study of the subject has come as the result of the researches of 

 Besredka and Steinhardt. 



Experimental Production of Anti-anaphylaxis. It has long been 

 known that the larger the first or sensitizing injection of antigen, the 

 greater must be the dose of the second or intoxicating injection, indicat- 

 ing that a large sensitizing injection introduces the factor tending to 

 produce the condition of anti-anaphylaxis. Partial desensitization, 

 or anti-anaphylaxis, may be produced by the injection of a sublethai 

 intoxicating dose of anaphylactogen during the period of incubation or 

 at its close. Quantitative relations between the size of the sensitizing, 

 intoxicating, and desensitizing doses of antigen and the period of in- 

 cubation have been worked out in a series of studies by Weil, 1 both in 

 the living guinea-pig and on the excised uterus, after the graphic method 

 of Dale. 2 Weil found that a small sensitizing dose of horse serum (0.01 

 c.c. subcutaneously) is followed by a relatively prolonged period of 

 incubation (from fourteen to sixteen days) ; that the minimal anaphy- 

 lactic or lethal dose is small (0.02 to 0.05 c.c.) ; that the blood, as a rule, 

 does not contain more than one sensitizing unit; and that the minimal 

 desensitizing dose is small (0.01 c.c.). Conversely, after repeated 

 large sensitizing doses (2 c.c. of serum subcutaneously on each of three 



1 Jour. Med. Research, 1913, 29, No. 2, 233; 1914, 30, No. 3, 299. 



2 Jour. Pharm. and Exper. Ther., 1913, iv, 167. 



