Contact and delayed hypersensitivity in the mouse. I. Active sensitization and passive transfer.

Ear swelling in mice was measured with a micrometer and used to quantify 24-hour skin reactions. Specific contact sensitivity occurred in mice immunized with picryl chloride, 2-phenyl-4-ethoxymethylene oxazolone, dinitrofluorobenzene and tetramethyl--phenylenediamine as shown by ear swelling 24 hours after challenge. In some mice sensitized with oxazolone significant swelling occurred 4 hours after challenge. It was possible to induce tolerance in adult mice and contact sensitivity to dinitrochlorobenzene was diminished by prior treatment with dinitrobenzenesulphonic acid. There was some evidence of delayed hypersensitivity to protein antigens. Twenty-four-hour skin reactions to PPD (purified protein derivative of tuberculin) occurred in mice immunized with live BCG or dead tubercle bacilli in Freund's adjuvant. In most experiments the swelling at 24 hours was greater than at 4 hours. Similar reactions to egg albumin and bovine γ-globulin were seen in mice immunized with these antigens in Freund's complete adjuvant and one group of mice showed greater swelling at 24 hours after challenge than at 4 hours. Contact sensitivity was readily transferred in inbred mice by peritoneal exudate cells when the challenge was undertaken immediately after transfer. Variable and usually inferior passive transfer was obtained with lymph node cells. Attempts to transfer contact sensitivity in outbred mice were unsuccessful.