THE IN VITRO DESENSITIZATION OF SENSITIVE CELLS BY TRYPSIN

Peritoneal exudate cells from animals exhibiting delayed hypersensitivity are inhibited from migrating in vitro by specific antigen. This inhibition is completely abolished by pretreatment of the sensitive cells with trypsin. The action of trypsin is prevented by soybean trypsin inhibitor. The results of experiments with mixtures of normal and sensitive cells suggest that trypsin alters an immunologic capacity of the sensitive cells. Trypsinized sensitive cells are capable of passively transferring delayed hypersensitivity and peritoneal cells taken from recipient animals are inhibited from migrating in vitro by specific antigen. These results suggest that the cells rapidly resynthesize the material removed by trypsin. The possible nature of the material removed by trypsin is discussed.

THE ACTION OF SOLUBLE ANTIGEN--ANTIBODY COMPLEXES IN PERFUSED GUINEA-PIG LUNG

When soluble antigen—antibody complexes, prepared in antigen excess, were injected into the perfused pulmonary artery of the unsensitized guinea-pig lung, they produced a bronchoconstrictor response which was associated with the appearance of histamine and a slow-reacting substance in the effluent. This activity was inhibited by the presence of normal rabbit serum or rabbit globulin; rabbit albumin and bovine γ-globulin produced no inhibition. Insoluble antigen—antibody complexes prepared at equivalence were at least 125 times less active than soluble complexes prepared in antigen excess. On comparing the activity of different solutions of soluble complex prepared in antigen excess ranging from 2½ to 160 times that required for equivalence, all were found to be equal. The properties of soluble antigen—antibody complexes are consistent with the possibility that circulating antibody may participate in in vivo anaphylaxis, if reached by an amount of antigen greater than that required for equivalence.

EMULSION THERAPY FOR ALLERGIC DISEASE. CLINICAL RESULTS WITH USE OF SMALL VOLUMES

In a series of cases in which emulsion repository desensitization therapy for allergic disease was carried out, the amount of emulsion injected was, for a time, one milliliter. Then, for a second period, the volume was reduced to 0.5 milliliter, and minor refinements of technique were introduced. Many of the patients treated in the first period were also treated in the second. The incidence of untoward reaction, ranging from mild soreness to the development of draining cysts at the site of injection into the arm, was greatly reduced between the first and second periods.