Readministration of IgE is required for repeated passive cutaneous anaphylaxis in mice

Background: Homologous passive cutaneous anaphylaxis (PCA) is an established technique that provides a useful tool to study local inflammation due to mast cell activation. Since mast cells are responsive to repeated challenge by IgE receptor crosslinking in vitro, we investigated the responsiveness of mice to repeated PCA activation. Methods: Female BALB/c mice were sensitized with intradermal injection of IgE into the ear and provocated through intravenous injection of trinitrophenol-BSA. Repeated provocation was administered, and the outcome was determined by colorimetrical measurement of Evans blue dye leakage. Results: After local IgE injection, mice could be challenged to demonstrate a PCA reaction at least up to 13 days after IgE sensitization. In contrast, passively sensitized mice did not respond to repeated antigen challenge, i.e. a second provocation administered between 1 and 12 days after the first PCA reaction. However, if these mice were intradermally resensitized with IgE at the same site after the first challenge, they became responsive to the repeated challenge. Conclusions: Mast cells become desensitized upon PCA reaction, and resensitization with IgE is critical for mice repeatedly stimulated by PCA activation.