Safety evaluation of recombinant human interleukin-4. I. Preclinical studies

Interleukin 4 Reduces Brain Hyperexcitability after Traumatic Injury by Downregulating TNF-α, Upregulating IL-10/TGF-β, and Potential Directing Macrophage/Microglia to the M2 Anti-inflammatory Phenotype

Macrophage/microglia are activated after Traumatic brain injury (TBI), transform to inflammatory phenotype (M1) and trigger neuroinflammation, which provokes epileptogenesis. Interleukin-4 (IL-4) is a well-known drive of macrophage/microglia to the anti-inflammatory phenotype (M2). We tested effect of IL-4 on speed of epileptogenesis, brain expression of inflammatory and anti-inflammatory cytokines, and lesion size in TBI-injured male rats. Rats underwent TBI by Controlled Cortical Impact. Then 100 ng IL-4 was injected into cerebral ventricles. One day after TBI, pentylenetetrazole (PTZ) kindling started and development of generalized seizures was recorded. The lesion size, cell survival rate, TNF-α, TGF-β, IL-10, and Arginase1 (Arg1) was measured in the brain 6 h, 12 h, 24 h, 48 h, and 5 days after TBI. Astrocytes and macrophage/microglia activation/polarization was assessed by GFAP/Arg1 and Iba1/Arg1 immunostaining. TBI-injured rats were kindled by 50% less PTZ injections than control and sham-operated rats. IL-4 did not change kindling rate in sham-operated rats but inhibited acceleration of kindling rate in the TBI-injured rats. IL-4 decreased damage volume and number of destroyed neurons. IL-4 stopped TNF-α whereas upregulated TGF-β, IL-10, and Arg1 expressions. Iba1/Arg1 positive macrophage/microglia was notably increased 48 h after IL-4 administration. IL-4 suppresses TBI-induced acceleration of epileptogenesis in rats by directing TBI neuroinflammation toward an anti-inflammatory tone and inhibition of cell death.

Dual Roles of IFN-γ and IL-4 in the Natural History of Murine Autoimmune Cholangitis: IL-30 and Implications for Precision Medicine

Primary biliary cirrhosis (PBC) is a progressive autoimmune liver disease with a long natural history. The pathogenesis of PBC is thought to be orchestrated by Th1 and/or Th17. In this study, we investigated the role of CD4⁺ helper T subsets and their cytokines on PBC using our previous established murine model of 2-OA-OVA immunization. We prepared adeno-associated virus (AAV)-IFN-γ and AAV-IL-4 and studied their individual influences on the natural history of autoimmune cholangitis in this model. Administration of IFN-γ significantly promotes recruitment and lymphocyte activation in the earliest phases of autoimmune cholangitis but subsequently leads to downregulation of chronic inflammation through induction of the immunosuppressive molecule IL-30. In contrast, the administration of IL-4 does not alter the initiation of autoimmune cholangitis, but does contribute to the exacerbation of chronic liver inflammation and fibrosis. Thus Th1 cells and IFN-γ are the dominant contributors in the initiation phase of this model but clearly may have different effects as the disease progress. In conclusion, better understanding of the mechanisms by which helper T cells function in the natural history of cholangitis is essential and illustrates that precision medicine may be needed for patients with PBC at various stages of their disease process.

Neuronal Interleukin-4 as a Modulator of Microglial Pathways and Ischemic Brain Damage

After ischemic stroke, various damage-associated molecules are released from the ischemic core and diffuse to the ischemic penumbra, activating microglia and promoting proinflammatory responses that may cause damage to the local tissue. Here we demonstrate using in vivo and in vitro models that, during sublethal ischemia, local neurons rapidly produce interleukin-4 (IL-4), a cytokine with potent anti-inflammatory properties. One such anti-inflammatory property includes its ability to polarize macrophages away from a proinflammatory M1 phenotype to a "healing" M2 phenotype. Using an IL-4 reporter mouse, we demonstrated that IL-4 expression was induced preferentially in neurons in the ischemic penumbra but not in the ischemic core or in brain regions that were spared from ischemia. When added to cultured microglia, IL-4 was able to induce expression of genes typifying the M2 phenotype and peroxisome proliferator activated receptor γ (PPARγ) activation. IL-4 also enhanced expression of the IL-4 receptor on microglia, facilitating a "feedforward" increase in (1) their expression of trophic factors and (2) PPARγ-dependent phagocytosis of apoptotic neurons. Parenteral administration of IL-4 resulted in augmented brain expression of M2- and PPARγ-related genes. Furthermore, IL-4 and PPARγ agonist administration improved functional recovery in a clinically relevant mouse stroke model, even if administered 24 h after the onset of ischemia. We propose that IL-4 is secreted by ischemic neurons as an endogenous defense mechanism, playing a vital role in the regulation of brain cleanup and repair after stroke. Modulation of IL-4 and its associated pathways could represent a potential target for ischemic stroke treatment.

SIGNIFICANCE STATEMENT

Depending on the activation signal, microglia/macrophages (MΦ) can behave as "healing" (M2) or "harmful" (M1). In response to ischemia, damaged/necrotic brain cells discharge factors that polarize MΦ to a M1-like phenotype. This polarization emerges early after stroke and persists for days to weeks, driving secondary brain injury via proinflammatory mediators and oxidative damage. Our study demonstrates that, to offset this M1-like polarization process, sublethally ischemic neurons may instead secrete a potent M2 polarizing cytokine, interleukin-4 (IL-4). In the presence of IL-4 (including when IL-4 is administered exogenously), MΦ become more effective in the cleanup of ischemic debris and produce trophic factors that may promote brain repair. We propose that IL-4 could represent a potential target for ischemic stroke treatment/recovery.

Scientific and Regulatory Policy Committee Points-to-consider Paper*

Drug-induced vascular injury (DIVI) is a recurrent challenge in the development of novel pharmaceutical agents. Although DIVI in laboratory animal species has been well characterized for vasoactive small molecules, there is little available information regarding DIVI associated with biotherapeutics such as peptides/proteins or antibodies. Because of the uncertainty about whether DIVI in preclinical studies is predictive of effects in humans and the lack of robust biomarkers of DIVI, preclinical DIVI findings can cause considerable delays in or even halt development of promising new drugs. This review discusses standard terminology, characteristics, and mechanisms of DIVI associated with biotherapeutics. Guidance and points to consider for the toxicologist and pathologist facing preclinical cases of biotherapeutic-related DIVI are outlined, and examples of regulatory feedback for each of the mechanistic types of DIVI are included to provide insight into risk assessment.

T Cell Receptor Gene Therapy for Autoimmune Diseases

The current quality of autoimmune disease treatments is not satisfactory in regard to efficacy and safety. Antigen-specific immunotherapy is a future therapy that could achieve maximal efficacy with minimal adverse effects. T cells are essential components in antigen-specific immunity. However, we do not have a sufficient strategy for manipulating antigen-specific T cells. We propose that T cell receptor (TCR) gene transfer is a hopeful approach for antigen-specific immunotherapy. We confirmed the efficacy of TCR gene therapy in animal models of systemic autoimmune disease and arthritis. In lupus-prone NZB/W F1 mice, nucleosome-specific TCR and CTLA4Ig transduced cells suppressed autoantibody production and nephritis development. In the therapeutic experiment of collagen-induced arthritis (CIA), arthritis-related TCRs were isolated from single T cells accumulating in the arthritis site. Arthritis-related TCR and TNFRIg transduced cells or TCR and Foxp3 transduced cells suppressed arthritis progression and bone destruction. Therefore, engineered antigen-specific cells manipulated to express appropriate functional genes could be applied to specific immunotherapy.

Antigen-specific immunotherapy for autoimmune diseases

The status of autoimmune disease therapies is not satisfactory. Antigen-specific immunotherapy has potential as a future therapy that could deliver maximal efficacy with minimal adverse effects. Several trials of antigen-specific immunotherapy have been performed, but so far no clear directions have been established. With regard to antigen-specificity in the immune system, T cells are essential components. However, at present, we do not have a sufficient range of strategies for manipulating antigen-specific T cells. In this review, the authors propose that T cell receptor gene transfer could be used for antigen-specific immunotherapy. In the proposed technique, important disease-related and, thus, antigen-specific T cells in patients would first be identified, and then a pair of cDNAs encoding alpha and beta T cell receptors would be isolated from these single T cells. These genes would then be transferred into self lymphocytes. These engineered antigen-specific cells can also be manipulated to express appropriate functional genes that could then be applied to specific immunotherapy.

Dendritic cells transduced with SOCS-3 exhibit a tolerogenic/DC2 phenotype that directs type 2 Th cell differentiation in vitro and in vivo

Dendritic cells (DCs) have been suggested to direct a type of Th differentiation through their cytokine profile, e.g., high IL-12/IL-23 for Th1 (named DC1/immunogenic DCs) and IL-10 for Th2 (DC2/tolerogenic DCs). Suppressor of cytokine signaling (SOCS)-3 is a potent inhibitor of Stat3 and Stat4 transduction pathways for IL-23 and IL-12, respectively. We thus hypothesize that an enhanced SOCS-3 expression in DCs may block the autocrine response of IL-12/IL-23 in these cells, causing them to become a DC2-type phenotype that will subsequently promote Th2 polarization of naive T cells. Indeed, in the present study we found that bone marrow-derived DCs transduced with SOCS-3 significantly inhibited IL-12-induced activation of Stat4 and IL-23-induced activation of Stat3. These SOCS-3-transduced DCs expressed a low level of MHC class II and CD86 on their surface, produced a high level of IL-10 but low levels of IL-12 and IFN-gamma, and expressed a low level of IL-23 p19 mRNA. Functionally, SOCS-3-transduced DCs drove naive myelin oligodendrocyte glycoprotein-specific T cells to a strong Th2 differentiation in vitro and in vivo. Injection of SOCS-3-transduced DCs significantly suppressed experimental autoimmune encephalomyelitis, a Th1 cell-mediated autoimmune disorder of the CNS and an animal model of multiple sclerosis. These results indicate that transduction of SOCS-3 in DCs is an effective approach to generating tolerogenic/DC2 cells that then skew immune response toward Th2, thus possessing therapeutic potential in Th1-dominant autoimmune disorders such as multiple sclerosis.

Treatment of Autoimmune Disease by Adoptive Cellular Gene Therapy

Autoimmune disorders represent inappropriate immune responses directed at self-tissue. Antigen-specific CD4+ T cells and antigen-presenting dendritic cells (DCs) are important mediators in the pathogenesis of auto-immune disease and thus are ideal candidates for adoptive cellular gene therapy, an ex vivo approach to therapeutic gene transfer. Using retrovirally transduced cells and luciferase bioluminescence, we have demonstrated that primary T cells, T cell hybridomas, and DCs rapidly and preferentially home to the sites of inflammation in animal models of multiple sclerosis, arthritis, and diabetes. These cells, transduced with retroviral vectors to drive expression of various "regulatory proteins" such as IL-4, IL-10, IL-12p40, and anti-TNF scFv, deliver these immunoregulatory proteins to the inflamed lesions, providing therapy for experimental autoimmune encephalitis (EAE), collagen-induced arthritis (CIA), and nonobese diabetic mice (NOD).

Adoptive cellular gene therapy of autoimmune disease

Autoimmune disorders represent inappropriate immune responses directed at self-tissue. Because CD4+ T cells are important mediators in the pathogenesis of autoimmune disease, they are ideal candidates for cell-based gene therapy. Using retrovirally-transduced cells and luciferase bioluminescence, we have demonstrated that primary T cells and hybridomas, rapidly and preferentially home to the sites of inflammation in organ-specific autoimmune disease. These cells, transduced with retroviral vectors to drive expression of various 'regulatory proteins', such as IL-4, IL-10 and IL-12p40, deliver these immunoregulatory proteins to the inflamed lesions, providing therapy for experimental models of autoimmune disease such as EAE, CIA and NOD mice. This technique was originally developed in our lab in the murine model of multiple sclerosis, EAE, where T cell hybridomas reactive with myelin basic protein (MBP) were transduced to express and used to deliver the modulatory cytokine, IL-4. Recently we have observed that the cytokine receptor antagonist, IL-12p40 transduced anti-myelin basic protein (MBP) TCR-transgenic T cells (but not CII-reactive T cells) were effective in preventing EAE whereas the CII-reactive, but not MBP-reactive T cells, transduced to express IL-12p40, would treat CIA.

Adoptive immunotherapy of experimental autoimmune encephalomyelitis via T cell delivery of the IL-12 p40 subunit

CD4+ T cells are believed to play a central role in the initiation and perpetuation of autoimmune diseases such as multiple sclerosis. In the murine model for multiple sclerosis, experimental autoimmune encephalomyelitis, pathogenic T cells exhibit a Th1-like phenotype characterized by heightened expression of proinflammatory cytokines. Systemic administration of "regulatory" cytokines, which serve to counter Th1 effects, has been shown to ameliorate autoimmune responses. However, the inherent problems of nonspecific toxicity limit the usefulness of systemic cytokine delivery as a potential therapy. Therefore, we used the site-specific trafficking properties of autoantigen-reactive CD4+ T cells to develop an adoptive immunotherapy protocol that provided local delivery of a Th1 cytokine antagonist, the p40 subunit of IL-12. In vitro analysis demonstrated that IL-12 p40 suppressed IFN-gamma production in developing and effector Th1 populations, indicating its potential to modulate Th1-promoted inflammation. We have previously demonstrated that transduction of myelin basic protein-specific CD4+ T cells with pGC retroviral vectors can result in efficient and stable transgene expression. Therefore, we adoptively transferred myelin basic protein-specific CD4+ T cells transduced to express IL-12 p40 into mice immunized to develop experimental autoimmune encephalomyelitis and demonstrated a significant reduction in clinical disease. In vivo tracking of bioluminescent lymphocytes, transduced to express luciferase, using low-light imaging cameras demonstrated that transduced CD4+ T cells trafficked to the central nervous system, where histological analysis confirmed long-term transgene expression. These studies have demonstrated that retrovirally transduced autoantigen-specific CD4+ T cells inhibited inflammation and promoted immunotherapy of autoimmune disorders.

Lethal hepatitis after gene transfer of IL-4 in the liver is independent of immune responses and dependent on apoptosis of hepatocytes: a rodent model of IL-4-induced hepatitis

The putative role of IL-4 in human and animal models of hepatitis has not yet been directly determined. We now report that direct expression of IL-4 in the liver of rats or mice using recombinant adenoviruses coding for rat or mouse IL-4 (AdrIL-4 and AdmIL-4, respectively) results in a lethal, dose-dependent hepatitis. The hepatitis induced by IL-4 was characterized by hepatocyte apoptosis and a massive monocyte/macrophage infiltrate. IL-4-induced hepatitis was independent of T cell-mediated immune responses. Hepatitis occurred even after gene transfer of IL-4 into nude rats, CD8-depleted rats, cyclosporine A-treated rats, or recombinase-activating gene 2(-/-) immunodeficient mice. Peripheral depletion of leukocytes using high doses of cyclophosphamide, and/or the specific depletion of liver macrophages with liposome-encapsulated dichloromethylene diphosphonate in rats did not block lethal IL-4-induced hepatitis. Direct transduction of hepatocytes with adenoviruses was not essential, since injection of AdrIL-4 into the hind limb induced an identical hepatitis. Finally, primary rat hepatocytes in culture also showed apoptosis when cultured in the presence of rIL-4. IL-4-dependent hepatitis was associated with increases in the intrahepatic levels of IFN-gamma, TNF-alpha, and Fas ligand. Administration of AdmIL-4 to IFN-gamma, TNF-alpha receptor type I, or TNF-alpha receptor type II knockout mice also resulted in lethal hepatitis, whereas a moderate protection was observed in Fas-deficient lpr mice. IL-4-dependent hepatocyte apoptosis could be abolished by treatment with caspase inhibitory peptides. Our results thus demonstrate that IL-4 causes hepatocyte apoptosis, which is only partially dependent on the activation of Apo-1-Fas signaling and is largely independent of any immune cells in the liver.

Characterization of a novel negative regulatory element in the human interleukin 4 promoter

Interleukin 4 (IL-4) is a multifunctional cytokine that plays an important role in hematopoiesis, tumor cell growth, and cellular immune responses. Expression of the IL-4 gene is tightly controlled at the level of gene transcription, and many positive regulatory cis-elements have been identified in the proximal IL-4 promoter region. Relatively little is known about factors that downregulate IL-4 transcription. We performed a detailed deletional analysis of the proximal human IL-4 promoter and studied reporter gene activity in transiently transfected Jurkat T lymphoblasts. In this report, we characterize a novel negative regulatory element (termed P2 NRE) that is adjacent to a binding site for nuclear factor of activated T cells. Mutation of P2 NRE significantly enhanced the activity of a 175 base pair IL-4 promoter construct in transiently transfected Jurkat T lymphoblasts. Using nuclear extracts from Jurkat cells, we identify a candidate factor (termed Rep-1) that binds uniquely to the P2 NRE in DNA-binding assays. Rep-1 is not related to other factors previously shown to interact with the IL-4 promoter, and by UV cross-linking and SDS-PAGE analysis, we found that it migrates with a molecular mass of approximately 150 kDa. Characterizing the molecular mechanisms responsible for downregulating the IL-4 promoter should enhance our understanding of IL-4-gene dysregulation in disease states.

A phase I and pharmacokinetic study of subcutaneously-administered recombinant human interleukin-4 (rhuIL-4) in patients with advanced cancer

PURPOSE

To investigate the pharmacokinetics and tolerability of recombinant human interleukin-4 (rhuIL-4), administered by daily subcutaneous injection, in patients with advanced cancer.

PATIENTS AND METHODS

Fourteen patients with advanced cancer treated with rhuIL-4 at escalating dose levels of 0.25, 1.0 and 5.0 microg/kg/day, on days 1, 8-17, and 28-57. The primary endpoints of the study were toxicity of rhuIL-4 and the determination of the pharmacokinetics of rhuIL-4 when given by subcutaneous injection. Secondary endpoints included effects on blood counts, hematopoietic cell precursors, and various immunologic parameters.

RESULTS

rhuIL-4 was well tolerated at all three dose levels. Detectable serum levels of IL-4 were found in patients at the 1.0 and 5.0 microg/kg/day dose levels. Peak serum IL-4 levels were achieved about 2 h after injection and IL-4 was still detectable 8 h after injection. No grade 4 toxicities were observed and grade 3 toxicities were confined to fever, headache and raised hepatic alkaline phosphatase. No consistent hematological or immunologic effects were observed. Although therapeutic efficacy was not an endpoint, one complete response (Hodgkin's disease) was observed. One patient with chronic lymphocytic leukemia progressed on therapy.

CONCLUSION

rhuIL-4 up to 5.0 microg/kg/day is well tolerated when given by subcutaneous injection. Biologically relevant serum IL-4 levels can be achieved and sustained for at least 8 h after a single injection.

A Novel Human CC Chemokine, Eotaxin-3, Which Is Expressed in IL-4-Stimulated Vascular Endothelial Cells, Exhibits Potent Activity Toward Eosinophils

IL-4 has been shown to be involved in the accumulation of leukocytes, especially eosinophils, at sites of inflammation by acting on vascular endothelial cells. To identify novel molecules involved in the IL-4-dependent eosinophil extravasation, cDNA prepared from HUVEC stimulated with IL-4 was subjected to differential display analysis, which revealed a novel CC chemokine designated as eotaxin-3. The human eotaxin-3 gene has been localized to chromosome 7q11.2, unlike most other CC chemokine genes. The predicted mature protein of 71 aa showed 27–42% identity to other human CC chemokines. The recombinant protein induced a transient increase in the cytosolic Ca2+ concentration and in vitro chemotaxis on eosinophils. Furthermore, in cynomolgus monkeys, the accumulation of eosinophils was observed at the sites where the protein was injected. Eotaxin-3 inhibited the binding of 125I-eotaxin, but not 125I-macrophage inflammatory protein-1α, to eosinophils and acted on cell lines transfected with CCR-3, suggesting that eotaxin-3 recognized CCR-3. IL-13 as well as IL-4 up-regulated eotaxin-3 mRNA in HUVEC, whereas neither TNF-α, IL-1β, IFN-γ, nor TNF-α plus IFN-γ did. The expression profile of eotaxin-3 is different from those of eotaxin, RANTES, and monocyte chemoattractant protein-4, which are potent eosinophil-selective chemoattractants and are induced by either TNF-α or TNF-α plus IFN-γ. These results suggest that eotaxin-3 may contribute to the eosinophil accumulation in atopic diseases.

IL-4 potentiates IL-1beta- and TNF-alpha-stimulated IL-8 and MCP-1 protein production in human retinal pigment epithelial cells

PURPOSE

Human retinal pigment epithelial (HRPE) cells are involved in ocular inflammation by secretion of chemokines such as IL-8 and MCP-1. It has been shown in this and other laboratories that interleukin-1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) are potent inducers of HRPE IL-8 and MCP-1 secretion. The induced IL-8 and MCP-1 expression is often modulated by other proinflammatory factors in a synergistic manner. Modulation of IL-8 and MCP-1 production by interleukin-4 (IL-4), a important mediator in Th2-mediated immunity, and granulocyte/macrophage-colony-stimulating factor (GM-CSF), one of the cytokines secreted by HRPE has been reported in non-ocular cells. The aim of the present investigation was to study effects of these two cytokines alone or in combination with IL-1beta or TNF-alpha on HRPE IL-8 and MCP-1 generation.

METHODS

The primary culture of HRPE cells was stimulated with various doses of IL-4, GM-CSF, IL-1beta and TNF-alpha alone or in combination for 8 or 24 hr. The supernatants were subjected to enzyme-linked immunosorbent assay (ELISA) for IL-8 and MCP-1. The mRNAs were isolated from the corresponding cells for Northern blot analysis.

RESULTS

IL-1beta and TNF-alpha induced dose-dependent increases in HRPE IL-8 and MCP-1 secretion with maximal stimulation observed at 2-5 ng/ml. IL-4 alone (100 ng/ml) resulted in a slight increase of MCP-1 and IL-8 secretion. When IL-4 was co-administrated with IL-1beta or TNF-alpha, two to three-fold increases in IL-8 and MCP-1 were observed over the maximal levels induced by IL-1beta or TNF-alpha alone. Northern blot analyses revealed that IL-4 did not alter the steady-state MCP-1 mRNA stimulated by IL-1beta and TNF-alpha, or alter the IL-8 mRNA stimulated by TNF-alpha, although the IL-1beta-induced IL-8 mRNA was slightly enhanced by higher concentrations of IL-4 (100 ng/ml).

CONCLUSION

The synergistic action by IL-4 occurs predominately at the post-transcriptional level. In contrast to IL-4, GM-CSF alone or in combination with IL-1beta or TNF-alpha did not generate additional secretion of HRPE IL-8 and MCP-1. HRPE IL-8 and MCP-1 gene expression and protein production are stimulated by IL-1beta or TNF-alpha through pathways differentially modulated by IL-4 and GM-CSF.

Safety evaluation of recombinant human interleukin-4. II. Clinical studies

The safety and tolerability of Escherichia coli-derived recombinant human interleukin-4 (rhuIL-4) have been evaluated in phase I and phase II studies in human patients with a variety of malignancies. Clinical trials have demonstrated that subcutaneous administration of rhuIL-4 is safe and well tolerated at doses as high as 5 micrograms/kg/day and as high as 10 micrograms/kg when administered 3 times/week. Although preclinical safety studies in cynomolgus monkeys demonstrated a number of adverse effects following repeated daily dosing with rhuIL-4, similar effects have generally not been observed in human patients.