Mouse paw anaphylaxis.

Anaphylactic swelling passively transferred to the hind paws of mice with homologous antibodies was investigated. The ascites fluid containing homocytotropic antibodies of the IgG1 class in a high concentration was obtained by repeated injections of bovine serum albumin in complete Freund's adjuvant into the peritoneal cavity of female ICR mice. The standard procedure for mouse paw anaphylaxis defined was as follows: female ICR mice received subcutaneously 25 microliters of a 1:20 diluted ascites in the hind footpad and 2 h later were given intravenously 1.0 mg of the antigen in saline, and subsequently at 5 min intervals paw thickness was assessed by means of a simple thickness gauge. Maximal paw edema occurred invariably 15 min after antigen challenge. Sex difference in response was not observed. Heating at 56 degrees C for 4 h resulted in a reduction of the activity of mouse ascites by approximately 40%. Histological examinations revealed that paw anaphylaxis was accompanied by mast cell degranulation and release of biologically active constituents from mast cell granules. Promethazine, pyrilamine, diphenhydramine, methysergide, cyproheptadine, ketotifen and phenoxybenzamine provided significant protection from the anaphylactic reaction in mice, while bromocriptine, dexamethasone and indomethacin were inactive. Relative drug effectiveness in paw anaphylaxis, passive cutaneous anaphylaxis and active and passive systemic anaphylaxis in mice was compared and discussed. Consequently, it was shown that mouse paw anaphylaxis was not only convenient for quantitative assessment of homocytotropic antibodies, but also useful in the routine work for screening of potential anti-allergic drugs.