Quantitative Studies on the Anaphylactic Mast‐Cell Reaction In Vivo in the Guinea Pig

The anaphylactic reaction of tissue mast cells was studied quantitatively in vivo in the nasal mucosa of anaesthetized guinea pigs. Rising doses of antigen, given intraarterially or intravenously, caused proportional degrees of mast‐cell depletion in the tissue, as well as increasing intensity of the anaphylactic shock symptoms. Topical administration of different concentrations of antigen on the mucosa produced proportional degrees of mast‐cell disappearance, but gave no shock symptoms. A total mast‐cell loss in the mucosa was never seen, even following very high doses of antigen. The cell reaction was temporally closely connected to the onset of the anaphylactic shock symptoms. Maximum was found in 1 minute after intraarterial, and in 2 minutes after topical administration of antigen. The cell reaction and the corresponding anaphylactic shock could not be produced until the 9th day following the first sensitizing dose, but both could be provoked during more than 11 months after sensitization. The conclusion is drawn that the anaphylactic reaction in a guinea‐pig tissue is quantitatively reflected in the disappearance of the tissue mast cells.