CYCLOPHOSPHAMIDE-INDUCED TOLERANCE IN FULLY ALLOGENEIC HEART-TRANSPLANTATION IN MICE

We have established a long-lasting heart allograft tolerance in H-2-in compatible combinations by intravenous injection of 10(8) allogeneic s pleen cells followed by the administration of 200 mg/kg of cyclophosph amide (CP). When C57BL/10 mice (B10, H-2(b)) were primed iv with 1 X 1 0(8) viable spleen cells from naive BALB/c mice (H-2(d)) and treated i p with 200 mg/kg CP 2 days later, BALB/c heart allografts were lasting in the recipients for as long as 8 weeks. On the other hand, B10 mice receiving either allogeneic spleen cells or CP rejected the heart all ograft within 10 days after transplantation. A direct approach assessi ng the donor-reactive T cells for frequency and reactivity showed that the donor-reactive T cells were partially deleted and the rest were r endered unresponsive. CP-induced tolerance may be applied for the indu ction of antigen-specific tolerance to allogeneic heart transplantatio n. (C) 1994 Academic Press, Inc.