Preclinical Efficacy of VTX-0811: A Humanized First-in-Class PSGL-1 mAb Targeting TAMs to Suppress Tumor Growth.

Omnipresent suppressive myeloid populations in the tumor microenvironment limit the efficacy of T-cell-directed immunotherapies, become more inhibitory after administration of T-cell checkpoint inhibitors, and are overall associated with worse survival of cancer patients. In early clinical trials, positive outcomes have been demonstrated for therapies aimed at repolarizing suppressive myeloid populations in the tumor microenvironment. We have previously described the key role of P-selectin glycoprotein ligand-1 (PSGL-1) in maintaining an inhibitory state of tumor-associated macrophages (TAMs), most of which express high levels of PSGL-1.

Antibodies Targeting Human or Mouse VSIG4 Repolarize Tumor-Associated Macrophages Providing the Potential of Potent and Specific Clinical Anti-Tumor Response Induced across Multiple Cancer Types.

V-set immunoglobulin domain-containing 4 (VSIG4) is a B7 family protein with known roles as a C3 fragment complement receptor involved in pathogen clearance and a negative regulator of T cell activation by an undetermined mechanism. VSIG4 expression is specific for tumor-associated and select tissue-resident macrophages. Increased expression of VSIG4 has been associated with worse survival in multiple cancer indications.

PSGL-1 Blockade Induces Classical Activation of Human Tumor-associated Macrophages.

Unlabelled: The immune suppressive microenvironment is a major culprit for difficult-to-treat solid cancers. Particularly, inhibitory tumor-associated macrophages (TAM) define the resistant nature of the tumor milieu. To define tumor-enabling mechanisms of TAMs, we analyzed molecular clinical datasets correlating cell surface receptors with the TAM infiltrate.

Macrophages - Controlling the Bifurcation Between Tumor Existence or Regression.

Macrophages are multifunctional cells that are employed by the tumor to further its growth and adaptation. While tumor-associated macrophages (TAMs) have widely diverse phenotypes, tumors coevolve with the ones that can promote tumorigenesis. Functionally, TAMs/myeloid cells constitute the largest negative influence on the tumor microenvironment and need to be reprogrammed in order to enable successful anti-tumor response in most tumors.

Characterization of MK-4166, a Clinical Agonistic Antibody That Targets Human GITR and Inhibits the Generation and Suppressive Effects of T Regulatory Cells.

GITR is a T-cell costimulatory receptor that enhances cellular and humoral immunity. The agonist anti-mouse GITR antibody DTA-1 has demonstrated efficacy in murine models of cancer primarily by attenuation of T-mediated immune suppression, but the translatability to human GITR biology has not been fully explored. Here, we report the potential utility of MK-4166, a humanized GITR mAb selected to bind to an epitope analogous to the DTA-1 epitope, which enhances the proliferation of both naïve and tumor-infiltrating T lymphocytes (TIL).

Targeting CXCR3 reduces ligand-induced T-cell activation but not development of lung allergic responses.

Background: Asthma is a chronic airway inflammatory disease that is associated with a large influx of inflammatory cells. Several chemokines and chemokine receptors play critical roles in the development of allergic airway inflammation.

Objective: Because polarized human T(H)2 cells express a functional CXCR3 chemokine receptor, we evaluated the effects of a selective CXCR3 inhibitor in a mouse model of allergic airway disease.

Drug-induced hemolytic anemia and thrombocytopenia associated with alterations of cell membrane lipids and acanthocyte formation.

CXCR3 is a chemokine receptor, upregulated upon activation of T cells and expressed on nearly 100% of T cells in sites of inflammation. SCH 900875 is a selective CXCR3 receptor antagonist. Thrombocytopenia and severe hemolytic anemia with acanthocytosis occurred in rats at doses of 75, 100, and 150 mg/kg/day.

Kinetic assessment and therapeutic modulation of metabolic and inflammatory profiles in mice on a high-fat and cholesterol diet.

The kinetics of metabolic and inflammatory parameters associated with obesity were evaluated in a murine diet-induced obesity (DIO) model using a diet high in fat and cholesterol. Cellular infiltration and mediator production were assessed and shown to be therapeutically modulated by the PPARgamma agonist rosiglitazone. C57BL/6 mice were maintained on a 45% fat/ 0.

Characterization of a murine keyhole limpet hemocyanin (KLH)-delayed-type hypersensitivity (DTH) model: role for p38 kinase.

Molecular and cellular assessment of dermal delayed-type hypersensitivity (DTH) responses is a useful approach for evaluating the mechanism of action (MOA) of immunomodulatory agents. In the present report, we characterized the delayed-type hypersensitivity response induced by keyhole limpet hemocyanin (KLH), and validated its utility by evaluating an immunomodulator, BIRB-796. Intradermal KLH challenge of the ear pinna following subcutaneous antigen sensitization resulted in a pronounced skin inflammation that peaked at 24-48h.

Nmur1-/- mice are not protected from cutaneous inflammation.

Neuromedin U (Nmu) is a neuropeptide expressed primarily in the gastrointestinal tract and central nervous system. Previous reports have identified two G protein-coupled receptors (designated Nmur1 and Nmur2) that bind Nmu. Recent reports suggest that Nmu mediates immune responses involving mast cells, and Nmur1 has been proposed to mediate these responses.

Studies to investigate the in vivo therapeutic window of the gamma-secretase inhibitor N2-[(2S)-2-(3,5-difluorophenyl)-2-hydroxyethanoyl]-N1-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl]-L-alaninamide (LY411,575) in the CRND8 mouse.

Accumulation of amyloid beta-peptide (Abeta) is considered a key step in the etiology of Alzheimer's disease. Abeta is produced by sequential cleavage of the amyloid precursor protein by beta- and gamma-secretase enzymes. Consequently, inhibition of gamma-secretase provides a promising therapeutic approach to treat Alzheimer's disease.

The human herpes virus 8-encoded chemokine receptor is required for angioproliferation in a murine model of Kaposi's sarcoma.

Kaposi's sarcoma (KS)-associated herpesvirus or human herpes virus 8 is considered the etiological agent of KS, a highly vascularized neoplasm that is the most common tumor affecting HIV/AIDS patients. The KS-associated herpesvirus/human herpes virus 8 open reading frame 74 encodes a constitutively active G protein-coupled receptor known as vGPCR that binds CXC chemokines with high affinity. In this study, we show that conditional transgenic expression of vGPCR by cells of endothelial origin triggers an angiogenic program in vivo, leading to development of an angioproliferative disease that resembles KS.

IFN-gamma determines distinct clinical outcomes in autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the CNS initiated by autoreactive CD4(+) T cells. EAE classically presents with a progressive ascending paralysis and is a model of multiple sclerosis that recapitulates some aspects of the disease. In this report we describe a mouse strain that spontaneously develops a severe, nonclassical form of EAE with 100% incidence.

Inhibition of intimal hyperplasia in transgenic mice conditionally expressing the chemokine-binding protein M3.

Chemokines have been implicated in the pathogenesis of a wide variety of diseases. This report describes the generation of transgenic mice that conditionally express M3, a herpesvirus protein that binds and inhibits chemokines. In response to doxycycline, M3 expression was induced in a variety of tissues and M3 was detectable in the blood by Western blotting.

Chronic treatment with the gamma-secretase inhibitor LY-411,575 inhibits beta-amyloid peptide production and alters lymphopoiesis and intestinal cell differentiation.

Inhibition of gamma-secretase, one of the enzymes responsible for the cleavage of the amyloid precursor protein (APP) to produce the pathogenic beta-amyloid (Abeta) peptides, is an attractive approach to the treatment of Alzheimer disease. In addition to APP, however, several other gamma-secretase substrates have been identified (e.g.

Conditional expression of murine Flt3 ligand leads to expansion of multiple dendritic cell subsets in peripheral blood and tissues of transgenic mice.

The analysis of the development and function of distinct subsets of murine dendritic cells (DC) has been hampered by the limited number of these cells in vivo. To circumvent this limitation we have developed a conditional transgenic mouse model for producing large numbers of DC. We used the tetracycline-inducible system to conditionally express murine Flt3 ligand (FL), a potent hemopoietic growth factor that promotes the differentiation and mobilization of DC.

Transient lung-specific expression of the chemokine KC improves outcome in invasive aspergillosis.

Invasive aspergillosis is a common and devastating pneumonia in immunocompromised hosts. Neutrophils are critical for defense against this infection, and ELR+ CXC chemokines are potent neutrophil chemoattractants. We hypothesized that transient lung-specific overexpression of one such ligand, KC, in mice with invasive aspergillosis improves the outcome of disease.

Ectopic expression of the murine chemokines CCL21a and CCL21b induces the formation of lymph node-like structures in pancreas, but not skin, of transgenic mice.

The CC chemokine CCL21 is a potent chemoattractant for lymphocytes and dendritic cells in vitro. In the murine genome there are multiple copies of CCL21 encoding two CCL21 proteins that differ from each other by one amino acid at position 65 (either a serine or leucine residue). In this report, we examine the expression pattern and biological activities of both forms of CCL21.

Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity.

ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein-coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease.

Disruption of neutrophil migration in a conditional transgenic model: evidence for CXCR2 desensitization in vivo.

We developed transgenic mice conditionally expressing the neutrophil chemoattracting chemokine KC and the beta-galactosidase gene in multiple tissues. In these transgenic mice, doxycycline treatment induced a strong up-regulation in the expression of KC in several tissues, including heart, liver, kidney, skin, and skeletal muscle. Expression of KC within these tissues led to a rapid and substantial increase in the serum levels of KC (serum KC levels were higher than 200 ng/ml 24 h after treatment).

Generation and analysis of mice lacking the chemokine fractalkine.

Fractalkine (CX(3)CL1) is the first described chemokine that can exist either as a soluble protein or as a membrane-bound molecule. Both forms of fractalkine can mediate adhesion of cells expressing its receptor, CX(3)CR1. This activity, together with its expression on endothelial cells, suggests that fractalkine might mediate adhesion of leukocytes to the endothelium during inflammation.

Impaired pulmonary host defense in mice lacking expression of the CXC chemokine lungkine.

Lungkine (CXCL15) is a novel CXC chemokine that is highly expressed in the adult mouse lung. To determine the biologic function of Lungkine, we generated Lungkine null mice by targeted gene disruption. These mice did not differ from wild-type mice in their hematocrits or in the relative number of cells in leukocyte populations of peripheral blood or other tissues, including lung and bone marrow.

Regulatory effects of interleukin-4 and interleukin-10 on human neutrophil function ex vivo and on neutrophil influx in a rat model of arthritis.

Objective: To assess the capacity of interleukin-4 (IL-4) and IL-10 to block polymorphonuclear neutrophil (PMN) activation in an ex vivo human model system, and to confirm their effect on neutrophil function in an animal model of arthritis.

Methods: The ex vivo phagocytic capacity of cytokine-activated human PMNs was assessed by use of assays for measuring the ingestion of heat-killed yeast and by subsequent hexose-monophosphate shunt activation using nitroblue tetrazolium reduction. The in vivo activity of IL-4 and IL-10 was measured using a rat adjuvant arthritis model in which the mycobacterial antigen concentration was titrated to modify disease intensity.