^^^2 LOCAL TISSUE REACTIVITY 



Opic cites c\])c"i imc'iUs in wiiicli ilic admiiiistralioii ol a inas- 

 si\c (lose ol a (omparatively jnne ])i()tein {i.e., crystalline egg 

 alhuniiii) tausecl a conij^lete disa])peaiance ol jjrecipitin formed 

 in the blood as the residt of prexioiis injections of the same sub- 

 stance and gave rise to a definite desensitization of the animal 

 concerned. The same fact had been previously shown by Grineff 

 (1912) for egg white. It is clear that desensitization is due to a 

 partial or complete saturation ^vitli antigen of the antibodies 

 of the sensitized animal. The cjuantitative relationships l)etween 

 the antigen used for desensitization and the antibodies present in 

 the sensitized animals are extremely important. 



The demonstration of passive transfer clearly estafjlished that 

 anaphylaxis results from antigen -[-antibody interaction. The 

 anaphylactic reaction is specific. An animal sensitized to a given 

 protein reacts ^vith anaphylactic shock to a second injection of 

 the same protein. Animals sensitized simultaneously ^vith a variety 

 of proteins react specifically to each protein on test reinjection. 



Combinations /// vivo and in vitro of the antigen \k'\\\\ the anti- 

 body deprives the antibody of its poAver of conferring passive sen- 

 sitization upon normal animals. The amount of antigen required 

 for protection is approximately proportional to the concentration 

 of tlie antibody in the serum. But in the production of anaphy- 

 lactic shock the larger the amoiuit of the antibody appropri- 

 ately attached to the cells of the host, the smaller is the amount 

 of antigen necessary to elicit anaphylactic shock. Thus, there ex- 

 ists a fundamental difference between neutralization of toxin by 

 antitoxin, and neutraHzation of anaphylactic antibody by anti- 

 gen. The antitoxic antibody protects against toxin, whilst the 

 anaphylactic antibody confers sensitization and, for these reasons, 

 the greater the amount of antitoxic antibody, the more protection 

 exists; on the contrary, the greater the amount of ana- 

 phylactic antibody, the greater is the sensitization of the animal. 



Apart from inducing a state of bacterial hypersensitiveness, 

 which because of its individual features will receive separate 

 consideration, bacterial proteins are capable of producing typical 

 anaphylactic reactions apparently based solely on the same spe- 

 cific mechanism of antigen-f-antibody interaction of anaphylaxis. 



Tomcsik and Kurotchkin (1928) produced anaphylactic shock 

 with small amounts of haptenes from B. lactis aerogenes, pneu- 

 mobacillus and yeast in guinea pigs sensitized with immune 

 serum of rabbits. It was possible to produce specific desensitiza- 



