Differential responses of tracheal and bladder segments isolated from control and mast cell - Deficient mice to antigen challenge following actively and passively sensrnzation

Immunological responses are associated with numerous urological diseases including interstitial cystitis (1C). Recent epidemologic studies of patients with 1C indicate that at least 50% also have some form of allergy. These findings suggest an immunological etiology involving mast cells might occur in at least a subset of 1C patients. We hoped to investigate the participation of mast cells on bladder inflammation using mast cell deficient W/W mice. In preliminary experiments performed to establish the model, both histamine and mast cells were found in the bladders of W/Wv animals. Moreover, mast cell numbers in the WAVmice were increased following immunization with DNP-OVA. Similarly, mast cell numbers in control (+/+) mice also increased due to active sensitization with DNP-OVA. Further studies revealed that both WAV and +/+ mice could be passively sensitized m vivo by i.v. injection of anti-DNP IgE. The antigen (DNP-HSA) responses of isolated trachea! and urinary bladder segments then were studied in vitro. Regardless of the method of sensitization, the WAVtrachea! segments did not respond to antigen challenge. In contrast, bladder segments from both actively and passively sensitized WAVanimals responded to antigen challenge with contraction and concomitant histamine release. We conclude that there are fundamental differences between trachea! and Madder segments in response to antigen challenge in WAVanimals and that these mice may not be a suitable model for the study of the involvement of bladder mast cells in inflammation. However, we also have shown that m vivo passive sensitization offers a quick and efficient means to study IgE-mediated reactions.