Immunosuppressive properties of an isoxazolo[5,4-E] triazepine compound in laboratory rodent models

The aim of this study was to evaluate potential immunosuppressive properties of the compound in mice and rats. We found that RM33 significantly inhibited the humoral immune response to and the delayed type hypersensitivity (DTH) to sheep red blood cells (SRBC). RM33 was effective when given intraperitoneally (i.p.) or per os and it also inhibited the effector phase of DTH. The compound, in addition, inhibited lipopolysacharide (LPS)- induced tumor necrosis alpha (TNF alpha) serum levels in mice. In rats, the compound given 1-3 days prior to carrageenan administration, significantly lowered the foot pad edema. That effect was accompanied by a decrease of serum TNF alpha level. Taken together, RM33 exhibited significant immunosuppressive activities in the specific immune response and anti-inflammatory action against carrageenan, a nonspecific irritant.