Immediate Hypersensitivity Reactions Induced in Mice by Active and Passive Means

Abstract

Immediate hypersensitivity of the Arthus type was produced in mice sensitized actively or passively. The most successful procedure of producing strong hypersensitivity to hen's egg albumin (HEA) was by subcutaneous injection of 0.5 to 1 mg in Freund's adjuvant, either containing or lacking mycobacteria, and then skin testing them successively on the 20th, 25th and 30th days thereafter. Almost 100% of the mice react strongly during the second and third skin test. The circulating antibody response showed that whenever skin test reactions are observed, circulating antibodies are present and that skin test with as little as 0.8 µg of HEA produced a noticeable increase in circulating antibody titers as well as enhancement of skin sensitivity. The Arthus reactions produced by transferring hyperimmune mouse serum to mice were similar to those produced in actively sensitized animals. It required at least 250 µg of mouse anti-HEA antibody nitrogen given intraperitoneally to produce skin sensitivity. As much as 1000 µg of AbN of a rabbit anti-HEA serum failed to produce visible skin sensitization. Histologic studies of the skin reactions showed that the predominant cell type infiltrating the reaction site was the polymorphonuclear leukocyte. Only in those mice sensitized with HEA in complete Freund's adjuvant were there, at 24 to 48 hr after skin test, a few areas with mononuclear cells present. It was concluded that the reactions observed were of the Arthus type and that the 24-hr reactions observed were residual Arthus reactions. No true delayed hypersensitivity to HEA was observed.