Tritiated thymidine incorporation and cell-mediated lympholysis as correlates of acute graft-versus-host reaction.

The graft-versus-host (GVH) reaction remains a serious consequence of administration of allogeneic immunocompetent cells to an immunosuppressed host even if donors and recipients are matched for major histocompatibility loci. This report describes a murine model for acute GVH reactions. Spleen cells from C3H/He (H-2k) mice, after intravenous injection of BALB/c (H-2d) spleen cells, were specifically cytotoxic for C3H target cells in vitro 4 days after irradiation and reconstitution. The cells in the recipients apparently are of donor genotype. The spleen cells exhibited rapid proliferation in vitro as measured by the uptake of 3H-TdR. The in vitro proliferation was distinguished from erythropoiesis by an assay of 59Fe incorporation. The kinetics of the in vitro incorporation of 3H-TdR and the in vivo uptake of 59Fe are reported.