Reconstitution of Lethally Irradiated Adult Mice with Dominant Negative TGF-β Type II Receptor-Transduced Bone Marrow Leads to Myeloid Expansion and Inflammatory Disease

Abstract

TGF-β regulation of immune homeostasis has been investigated in the context of cytokine knockout (TGF-β null) mice, in which particular TGF-β isoforms are disrupted throughout the entire organism, as well as in B and T cell-specific transgenic models, but to date the immunoregulatory effects of TGF-β have not been addressed in the context of an in vivo mouse model in which multi-isoform TGF-β signaling is abrogated in multiple leukocyte lineages while leaving nonhemopoietic tissue unaffected. Here we report the development of a murine model of TGF-β insensitivity limited to the hemopoietic tissue of adult wild-type C57BL/6 mice based on retroviral-mediated gene transfer of a dominant negative TGF-β type II receptor targeting murine bone marrow. Unlike the lymphoproliferative syndrome observed in TGF-β1-deficient mice, the disruption of TGF-β signaling in bone marrow-derived cells leads to dramatic expansion of myeloid cells, primarily monocytes/macrophages, and is associated with cachexia and mortality in lethally irradiated mice reconstituted with dominant negative receptor-transduced bone marrow. Surprisingly, there was a notable absence of T cell expansion in affected animals despite the observed differentiation of most cells in the T cell compartment to a memory phenotype. These results indicate not only that TGF-β acts as a negative regulator of immune function, but that lack of functional TGF-β signaling in the myeloid compartment of adult mice may trigger suppression of lymphocytes, which would otherwise proliferate when rendered insensitive to TGF-β.

Blockade of transforming growth factor-β signaling in tumor-reactive CD8+ T cells activates the antitumor immune response cycle

“…Such examples are abundant in the literature. Our own experience has indicated that transfer of non-tumor-specific CD8 + T cells to recipients will lead to widespread inflammatory disease (12,13). In the present study, the situation is more critical than the syngeneic systems, as the recipient is allogeneic to the transferred CD8 + T cells.…”

“…The ex vivo culture was done as described previously (14). Tumor-reactive CD8 + T cells were rendered insensitive to TGF-h by infection with ThRIIDN-green fluorescent protein (GFP) -containing retrovirus as described previously (12,13). Infection efficiency was assessed by GFP expression and flow cytometry and was always >90%.…”

“…Adoptive transfer of these T cells allowed the generation of an immune response capable of inhibiting metastasis in mice challenged with murine thymoma EL-4 and melanoma B16 cells (11). In 2002, we reported the inhibition of metastasis of mouse prostate cancer TRAMP-C2 and mouse melanoma B16 by transplanting TGF-hinsensitive bone marrow cells into mice (12,13). In all studies described above, although antitumor response was encouraging, the nonspecific nature of the immune reaction led to the widespread inflammatory disease in the hosts (12).…”

“…In 2002, we reported the inhibition of metastasis of mouse prostate cancer TRAMP-C2 and mouse melanoma B16 by transplanting TGF-hinsensitive bone marrow cells into mice (12,13). In all studies described above, although antitumor response was encouraging, the nonspecific nature of the immune reaction led to the widespread inflammatory disease in the hosts (12). Most recently, we employed adoptive transfer of tumor-specific TGF-h-insensitive CD8 + T cells to tumorbearing immunocompetent mice and were able to eradicate established lung metastasis of TRAMP-C2 tumors (14,15).…”

Immune Cells, If Rendered Insensitive to Transforming Growth Factor-Beta, Can Cure Prostate Cancer

“…These investigators used transgenic mice with TGF-3 null expression targeted specifically to T cells. Subsequently, our study using transplant of TGF-pinsensitive bone marrow cells also demonstrated a total rejection of metastatic tumor cells 22 ' 23 However, in both studies, due to the non-specific nature of the immune cells, autoimmune disease eventually developed in the hosts. Results of our recent study have shown that adoptive transfer of tumorreactive TGF-p-insensitive CD8+ T cells were able to eradicate established lung metastasis of mouse prostate cancer cells, TRAMP-C2 24 .…”