Effect of selected immunoregulatory agents on low-grade contact sensitivity.

The effect of selected compounds with known immunoregulatory activity was examined in a 45-h sensitization period oxazolone contact-sensitivity reaction. Oxazolone sensitivity was induced by applying 0.1 ml of 5% oxazolone in absolute ethanol to the shaved abdomen of C57Bl/6 mice on day 0. Challenge with oxazolone followed 45 h later and was accomplished by painting a 5% solution of oxazolone in absolute ethanol on the left hindpaw. The response at 24 h was determined plethysmographically. Histamine (0.062-1.0 mg/kg, subcutaneously, twice a day), concanavalin A (0.31-5.0 mg/kg intravenously), penicillamine (6.25-25 mg/kg, subcutaneously), chloroquine (6.25-25 mg/kg, subcutaneously), and thymosin fraction 5 (0.125-1.25 mg/kg subcutaneously) all stimulated the oxazolone reaction when administered on day 0. These data suggest that the low-grade oxazolone response may be a useful assay to detect immunostimulatory activity.