Penicillin G-induced cutaneous anaphylaxis in the guinea pig

Allergic cutaneous responses were induced by intradermal injection of penicillin G (PCG) and PCG-bovine serum albumin (BSA) conjugates onto the back of guinea pig actively immunized with PCG potassium (25 mg/animal) incorporated in Freund's complete adjuvant. The PCG-induced response was characterized macroscopically by erythema and edema with a maximum level at 24 hrs after elicitation and microscopically by the infiltration with basophils, macrophages and lymphocytes following with neutrophils. In addition, intensity of macrophage-infiltration shared a similar time course change with those of erythema and edema. These suggest that this response is associated to a delayed type hypersensitivity of Jones-Mote type. On the other hand, in the PCG-BSA-induced response the edema with erythema at the early phase was a noticeable observation and this response disappeared within 12 hrs, although the erythema continued by 24 hrs. Microscopically, the degranulation of mast cells and severe infiltration with neutrophils in the early phase and the infiltration of eosinophils in the late phase accompanying the infiltration with monocytes, basophils and lymphocytes were characteristic findings, which suggest that PCG-BSA response is a similar hypersensitivity to an atopic dermatitis. As mentioned above, we confirmed two types of allergic cutaneous responses in the guinea pig immunized with PCG.