Graft-versus-leukemia in a retrovirally induced murine CML model: mechanisms of T-cell killing

Abstract

The graft-versus-leukemia (GVL) effect, mediated by donor T cells, has revolutionized the treatment of leukemia. However, effective GVL remains difficult to separate from graft-versus-host disease (GVHD), and many neoplasms are GVL resistant. Murine studies aimed at solving these problems have been limited by the use of leukemia cell lines with limited homology to human leukemias and by the absence of loss-of-function leukemia variants. To address these concerns, we developed a GVL model against murine chronic-phase chronic myelogenous leukemia (mCP-CML) induced with retrovirus expressing the bcr-abl fusion cDNA, the defining genetic abnormality of chronic-phase CML (CP-CML). By generating mCP-CML in gene-deficient mice, we have studied GVL T-cell effector mechanisms. mCP-CML expression of Fas or tumor necrosis factor (TNF) receptors is not required for CD8-mediated GVL. Strikingly, maximal CD4-mediated GVL requires cognate interactions between CD4 cells and mCP-CML cells as major histocompatibility complex-negative (MHC II ؊/؊ ) mCP-CML is relatively GVL resistant. Nevertheless, a minority of CD4 recipients cleared MHC II ؊/؊ mCP-CML; thus, CD4 cells can also kill indirectly. CD4 GVL did not require target Fas expression. These results suggest that CP-CML's GVL sensitivity may in part be explained by the minimal requirements for T-cell killing, and GVL-resistance may be related to MHC II expression. (Blood.

Central Memory CD8+ T Cells Induce Graft-versus-Host Disease and Mediate Graft-versus-Leukemia

“…Retroviral supernatants were generated by transfection of the Plat-E retrovirus packing cell line as described previously (28,29,31,32). p210-infected bone marrow progenitors were generated as described previously (28,29,32). Briefly, B6 mice were injected on day Ϫ6 with 5 mg of 5-fluorouracil (Pharmacia & Upjohn).…”

CD8+ but not CD4+ T cells require cognate interactions with target tissues to mediate GVHD across only minor H antigens, whereas both CD4+ and CD8+ T cells require direct leukemic contact to mediate GVL

“…Retroviral supernatants were generated by transfection of Plat-E retrovirus packing cell line 16 as described. [17][18][19] Progenitor infections p210-infected progenitors were generated as previously described. 13,17,19 Briefly, B6 mice were injected on day Ϫ6 with 5 mg 5-fluorouracil (Pharmacia & Upjohn, Kalamazoo, MI).…”

“…[17][18][19] Progenitor infections p210-infected progenitors were generated as previously described. 13,17,19 Briefly, B6 mice were injected on day Ϫ6 with 5 mg 5-fluorouracil (Pharmacia & Upjohn, Kalamazoo, MI). On day Ϫ2, BM cells were harvested and cultured in prestimulation media (Dulbecco modified Eagle medium, 15% fetal bovine serum, interleukin-3 (6 ng/mL), interleukin-6 (10 ng/mL), and stem-cell factor (10 ng/mL; all cytokines from PeproTech; Rocky Hill, NJ).…”

“…mCP-CML phenotypically resembles human CP-CML in that recipients of p210-infected BM cells develop a high white blood cell count and splenomegaly, with hematopoiesis dominated by maturing myeloid cells. 13,17,19 An advantage of this model is that we can induce mCP-CML in BM from any strain, including gene-deficient mice. The retroviral construct also expresses a nonsignaling truncated form of the BLOOD, 1 APRIL 2008 ⅐ VOLUME 111, NUMBER 7 For personal use only.…”

Control of graft-versus-host disease with maintenance of the graft-versus-leukemia effect in a murine allogeneic transplant model using retrovirally transduced murine suicidal lymphocytes

“…However, other studies have shown that larger numbers of lymphocytes can facilitate engraftment [39,40] and produce a greater GVL effect [41]. Consequently, we tested higher doses of TK + TC.…”