Effects of levamisole and D-penicillamine on contact sensitivity to oxazolone in rats

Levamisole, but not D-penicillamine, inhibited the oxazolone delayed hypersensitivity in rats. It was more effective when given locally to the ear (the tissue being challenged with oxazolone) or when injected intraperitoneally 24 h previously. Rats bred for resistance to the dextran anaphylactoid reaction exhibit contact sensitivity to oxazolone even better than rats which respond to clinical dextran.