Pharmacologic manipulation of a four day murine delayed type hypersensitivity model

A murine delayed-type hypersensitivity (DTH) model was developed as a tool for drug discovery. Time course studies indicated that hind paw swelling was maximal at four days post-sensitization with picryl chloride. A pharmacological survey involving daily administration of drugs revealed that as a class, the glucocorticoids (e.g. dexamethasone and corticosterone) were the most potent inhibitors of the DTH response. The immunosuppressants, methotrexate, cyclosporine A, cyclophosphamide, and azathioprine, were all able to suppress the DTH response, with methotrexate being the most potent suppressor of paw swelling. Likewise, non-steroidal anti-inflammatory agents (e.g. indomethacin, piroxicam, diclofenac, and naproxen) all suppressed the DTH response, with indomethacin and piroxicam being the most potent suppressors. A series of central nervous system affecting drugs, including serotonin agonists [e.g. trifluromethylphenylpiperazine (tfMPP), 1-(3-chlorophenyl)piperazine (mCPP), quipazine, and 8-hydroxy-DPAT hydrobromide (8-OH DPAT)], and serotonin antagonists (e.g. cyproheptadiene, ketanserin, and mianserin) were examined in the 4 day DTH model. Except for 8-OH DPAT, all of the serotonin agonists were able to suppress the DTH response, with mCPP being the most potent suppressor. In contrast, none of the tested serotonin antagonists had any effect on the DTH response. The histamine antagonists (e.g. cimetidine and chlorphineramine) were largely ineffective in suppressing the DTH response. These data provide a pharmacological profile for a series of immunomodulator, non-steroidal anti-inflammatory, and central nervous system active compounds in a classic immunologic model.