INTERLEUKIN-13, IN COMBINATION WITH ANTI INTERLEUKIN-12, INCREASES GRAFT PROLONGATION AFTER PORTAL VENOUS IMMUNIZATION WITH CULTURED ALLOGENEIC BONE-MARROW-DERIVED DENDRITIC CELLS

Portal venous (pv) transfusion before transplant with large numbers (1 00 x 10(6)) of irradiated multiple minor histoincompatible spleen cell s (B10.Br) augments allogeneic skin graft survival in C3H mice. We hav e shown in earlier studies that this is correlated with preferential a ctivation for production of type 2 cytokines (interleukin [IL]-4 and I L-10) and decreased production of type 1 cytokines (IL-2 and interfero n [IFN]gamma). We have also shown that recombinant (r)IL-12, in associ ation with anti-IL-10 monoclonal antibody, can reverse in vivo the gra ft prolongation afforded by pv immunization and the altered cytokine p roduction that follows. Adoptive transfer of inhibition of graft rejec tion is possible at early times after pv immunization, using plastic a dherent cells obtained from the liver of treated mice. We show below t hat within 4 days of pv immunization, dendritic cells (NLDC-145(+)) is olated from the thymus, mesenteric lymph node (MLN), and spleen of mic e receiving MHC-incompatible cells/grafts (C3H with C57BL/6), can tran sfer skin graft prolongation to naive C3H recipients. Moreover, 5 x 10 (6) cultured dendritic cells derived from 10-day cultures of C57BL/6 b one marrow also confer increased graft survival after pv immunization, but not after intravenous immunization. Once again, increased graft s urvival with cultured dendritic cells was associated with polarization of T cells that were isolated from treated mice to produce IL-4 and I L-10 on restimulation in vitro. Graft survival and polarization in cyt okine production was further enhanced by simultaneous administration o f anti-IL-12 monoclonal antibody, rIL-13, or more significantly, a com bination of anti-IL-la and rIL-13. These alterations were associated w ith persistence of donor cells in various tissues of recipient mice, a s assessed using polymerase chain reaction for expression of H-Y mRNA in female recipients of male bone marrow. Our data suggest that a comb ined strategy of donor-specific immunization before transplant and man ipulation of cytokine levels in vivo may prove an effective regimen in the induction of unresponsiveness in transplant recipients.