B effector cells activated by a chimeric protein consisting of IL-2 and the ectodomain of TGF-β receptor II induce potent antitumor immunity.

We have previously shown that interleukin (IL)-2 receptor-expressing lymphoid cells stimulated with a chimeric protein linking IL-2 to the ectodomain of TGF-β receptor II (also known as FIST) become resistant to TGF-β-mediated suppression and produce significant amounts of proinflammatory cytokines. In this study, we have characterized the antigen presentation properties of FIST-stimulated B cells (hereafter inducible B effector cells, iBEC). FIST converts naïve splenic B cells to B effector cells characterized by potent antigen presentation properties and production of TNFα and IFNγ.

A MCP1 fusokine with CCR2-specific tumoricidal activity.

Background: The CCL2 chemokine is involved in promoting cancer angiogenesis, proliferation and metastasis by malignancies that express CCR2 receptor. Thus the CCL2/CCR2 axis is an attractive molecular target for anticancer drug development.

Methods: We have generated a novel fusion protein using GMCSF and an N-terminal truncated version of MCP1/CCL2 (6-76) [hereafter GMME1] and investigated its utility as a CCR2-specific tumoricidal agent.

Erythropoietin gene-enhanced marrow mesenchymal stromal cells decrease cisplatin-induced kidney injury and improve survival of allogeneic mice.

Bone marrow-derived mesenchymal stromal cells (MSCs) are promising for regenerative medicine applications, such as for renoprotection and repair in acute kidney injury (AKI). Erythropoietin (Epo) can also exert cytoprotective effects on various tissues including the kidney. We hypothesized that MSCs gene-enhanced to secrete Epo may produce a significant beneficial effect in AKI.

Novel TGF-beta antagonist inhibits tumor growth and angiogenesis by inducing IL-2 receptor-driven STAT1 activation.

Carcinoma derived TGF-β acts as a potent pro-oncogenic factor and suppresses antitumor immunity. To antagonize TGF-β-mediated effects in tandem with a proinflammatory immune stimulus, we generated a chimeric protein borne of the fusion of IL-2 and the soluble extracellular domain of TGF-βR II (FIST). FIST acts as a decoy receptor trapping active TGF-β in solution and interacts with IL-2-responsive lymphoid cells, inducing a distinctive hyperactivation of STAT1 downstream of IL-2R, which in turn promotes SMAD7 overexpression.

A dendritic cell population generated by a fusion of GM-CSF and IL-21 induces tumor-antigen-specific immunity.

We have previously shown that the fusion of GM-CSF and IL-21 (GIFT-21) possesses a potent immune stimulatory effect on myeloid cells. In this study, we define the effect of GIFT-21 on naive murine monocytes (GIFT-21 dendritic cells [DCs]), which express increased levels of Gr-1, CD45R, MHC class I, CD80, CD86, and CXCR4 and suppress CD11c and MHC class II. Compared with conventional dendritic cells, GIFT-21 DCs produced substantially more CCL2, IL-6, TNF-α, and IFN-α and induced significantly greater production of IFN-γ by CD8(+) T cells in MHC class I-restricted Ag presentation assays.

Mesenchymal stromal cells expressing ErbB-2/neu elicit protective antibreast tumor immunity in vivo, which is paradoxically suppressed by IFN-gamma and tumor necrosis factor-alpha priming.

It is unknown whether mesenchymal stromal cells (MSC) can regulate immune responses targeting tumor autoantigens of low immunogenicity. We tested here whether immunization with MSC could break immune tolerance towards the ErbB-2/HER-2/neu tumor antigen and the effects of priming with IFN-γ and tumor necrosis factor-α (TNF-α) on this process. BALB/c- and C57BL/6-derived MSC were lentivirally transduced to express a kinase-inactive rat neu mutant (MSC/Neu).

Human marrow-derived mesenchymal stromal cells decrease cisplatin renotoxicity in vitro and in vivo and enhance survival of mice post-intraperitoneal injection.

Acute kidney injury (AKI) can occur from the toxic side-effects of chemotherapeutic agents such as cisplatin. Bone marrow-derived mesenchymal stromal cells (MSCs) have demonstrated wide therapeutic potential often due to beneficial factors they secrete. The goal of this investigation was to evaluate in vitro the effect of human MSCs (hMSCs) secretome on cisplatin-treated human kidney cells, and in vivo the consequence of hMSCs intraperitoneal (ip) implantation in mice with AKI.

A fusion of GMCSF and IL-21 initiates hypersignaling through the IL-21Ralpha chain with immune activating and tumoricidal effects in vivo.

We hypothesized that fusing granulocyte-macrophage colony-stimulation factor (GMCSF) and interleukin (IL)-21 as a single bifunctional cytokine (hereafter GIFT-21) would lead to synergistic anticancer immune effects because of their respective roles in mediating inflammation. Mechanistic analysis of GIFT-21 found that it leads to IL-21Ralpha-dependent STAT3 hyperactivation while also contemporaneously behaving as a dominant-negative inhibitor of GMCSF-driven STAT5 activation. GIFT-21's aberrant interactions with its cognate receptors on macrophages resulted in production of 30-fold greater amounts of IL-6, TNF-alpha, and MCP-1 when compared to controls.

A granulocyte-macrophage colony-stimulating factor and interleukin-15 fusokine induces a regulatory B cell population with immune suppressive properties.

We have previously shown that a granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-15 (IL-15) 'fusokine' (GIFT15) exerts immune suppression via aberrant signaling through the IL-15 receptor on lymphomyeloid cells. We show here that ex vivo GIFT15 treatment of mouse splenocytes generates suppressive regulatory cells of B cell ontogeny (hereafter called GIFT15 B(reg) cells). Arising from CD19+ B cells, GIFT15 B(reg) cells express major histocompatibility complex class I (MHCI) and MHCII, surface IgM and IgD, and secrete IL-10, akin to previously described B10 and T2-MZP B(reg) cells, but lose expression of the transcription factor PAX5, coupled to upregulation of CD138 and reciprocal suppression of CD19.

Allogeneic mesenchymal stem cells for treatment of experimental autoimmune encephalomyelitis.

The use of allogeneic "universal donor" mesenchymal stromal cells (MSCs) may be a substantial clinical convenience for treatment of autoimmune ailments such as multiple sclerosis. We therefore tested whether allogeneic MSCs can be exploited for treatment of experimental autoimmune encephalomyelitis (EAE) in mice with otherwise intact immune system. Administration of allogeneic Balb/c-derived MSCs to C57Bl/6 mice with pre-established EAE led to a significant decrease in disease score over time comparable to that achieved with syngeneic MSCs, and was correlated with a significant blunting of immune cell infiltration to the spinal cord and reduced circulating levels of interferon-gamma (IFN-gamma) and interleukin-17.

Mesenchymal stromal cells ameliorate experimental autoimmune encephalomyelitis by inhibiting CD4 Th17 T cells in a CC chemokine ligand 2-dependent manner.

The administration of ex vivo culture-expanded mesenchymal stromal cells (MSCs) has been shown to reverse symptomatic neuroinflammation observed in experimental autoimmune encephalomyelitis (EAE). The mechanism by which this therapeutic effect occurs remains unknown. In an effort to decipher MSC mode of action, we found that MSC conditioned medium inhibits EAE-derived CD4 T cell activation by suppressing STAT3 phosphorylation via MSC-derived CCL2.

Selective inhibition of CCR2 expressing lymphomyeloid cells in experimental autoimmune encephalomyelitis by a GM-CSF-MCP1 fusokine.

We describe the generation of a fusion cytokine consisting of GM-CSF in tandem with N-terminal-truncated MCP-1 (6-76), hereafter GMME1. Treatment of activated T cells with recombinant GMME1 protein leads to proinflammatory cytokine reduction and apoptosis via a CCR2-restricted pathway. Similarly, cell death is triggered in macrophages cultured with GMME1, while an inhibition of Ab production from plasma cells is observed.

Mesenchymal stromal cell-derived CCL2 suppresses plasma cell immunoglobulin production via STAT3 inactivation and PAX5 induction.

We demonstrate that the secretome of mesenchymal stromal cells (MSCs) suppresses plasma cell (PC) immunoglobulin (Ig) production, induces plasmablast proliferation, and leads to interleukin-10-mediated blockade in vitro. We found that these effects are the result of MSC-derived CC chemokine ligands CCL2 and CCL7. More specifically, MSCs further processed these CC chemokines by the activity of matrix metalloproteinases (MMPs), leading to the generation of proteolytically processed antagonistic CCL2 variant.