• 1 April 1969
    • journal article
    • Vol. 4  (4) , 423-34
Abstract
Permanent specific immunological unresponsiveness can be produced in guinea-pigs already sensitive to K2Cr2O7 by the combination of an intravenous injection of 20 mg/kg K2Cr2O7 and an epicutaneous contact with K2Cr2O7 within 24 hr; 2 mg/kg K2Cr2O7 produces only temporary desensitization. Methotrexate and cyclophosphamide for 1 week at the time of the intravenous injection increased the intensity of the suppression but did not prolong the unresponsiveness. Anti-thymocyte serum alone had no effect. A combination of cyclophosphamide and anti-thymocyte serum for 1 week at the time of the intravenous injection prolonged the unresponsiveness for 2 months, but the animals regained sensitivity by 3 months. The addition of prednisolone to this combination, reduced the duration of unresponsiveness produced by a combination of the specific sensitizer, cyclophosphamide and anti-thymocyte serum.