Fetal liver transplantation in mice: tolerance induction by portal venous inoculation with allogeneic cells followed by injection of cyclophosphamide]

BALB/C mice (H-2d) receiving allogeneic C57 mice (H-2b) spleen cells via the portal vein (PV), followed by administration of cyclophosphamide (CY), abrogated the capability of rejecting allogeneic EL-4G- tumor cells (C57 origin). BALB/C mice received this combined treatment and BALB/C mice untreated or treated with either PV presensitization or CY injection were all exposed to 7.5 Gy total body irradiation, which was confirmed to be a lethal dose for BALB/C mice, then given intravenously 2 x 10(7) fetal liver cells from C57 mice (FLC57). The results indicated that the survival times of grafted BALB/C mice combined treatment were longer than those of untreated or either PV or CY treated, (PV + CY + 7.5Gy + FLC 57: MST = 99.5 +/- 12.6 day), v(N + 7.5GY + FLC57: MST = 36.5 +/- 9.8 day; PV + 7.5Gy + FLC57: MST = 12.2 +/- 0.2 day; CY + 7.5Gy + FLC57: MST = 27.6 +/- 5.5 day). The difference was statistically significant. The spleen cells from the grafted mice were assessed by indirect immunofluorescence with anti-C57 serum. The spleen cells from BALB/C mice with survival time over 100 days after grafting of FLC57 in combined treatment group were about 70-80 percentage of C57 positive cells.