Enhancement of graft-versus-host reaction and delayed cutaneous hypersensitivity in mice by ubenimex

The effect of ubenimex on graft-versus-host reaction and delayed cutaneous hypersensitivity in mice was studied. Ubenimex enhanced the graft-versus-host reaction in a dose range from 0.005 to 0.5 mg/kg. Ubenimex inhibited the aging-caused decrease of delayed cutaneous hypersensitivity to oxazolone and the efficacy was greater with older mice. Ubenimex also inhibited mitomycin C and L1210-caused decreases of delayed cutaneous hypersensitivity to picryl chloride. However, the excess decrease caused by mitomycin C was not significantly altered by ubenimex.