Impaired cutaneous delayed-type hypersensitivity in autoimmune MRL lpr/lpr mice.

A number of phenotypic and functional T-cell abnormalities have been reported in autoimmune MRL lpr/lpr (MRL/l) mice. We examined hapten-specific delayed-type hypersensitivity (DTH) responses in male and female MRL/l mice and compared them to age- and sex-matched congeneic MRL +/+ (MRL/n) mice and outbred Swiss controls. Profound defects in DTH reactivity were demonstrated in female MRL/l mice at all ages tested. In contrast MRL/l males displayed only partly impaired and selective DTH defect toward one of the two haptens used. Congeneic MRL/n females expressed lower DTH reactivity than their male littermates. We conclude that DTH responses in autoimmune MRL/l mice are defective and sex hormone related.