Publications by authors named "Frances R Bahjat"

Targeting CD40 with agonist antibodies is a promising approach to cancer immunotherapy. CD40 acts as a master regulator of immunity by mobilizing multiple arms of the immune system to initiate highly effective CD8 + T-cell-mediated responses against foreign pathogens and tumors. The clinical development of CD40 agonist antibodies requires careful optimization of the antibody to maximize therapeutic efficacy while minimizing adverse effects.

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Each year, thousands of patients are at risk of cerebral ischemic injury, due to iatrogenic responses to surgical procedures. Prophylactic treatment of these patients as standard care could minimize potential neurological complications. We have shown that protection of brain tissue, in a non-human primate model of cerebral ischemic injury, is possible through pharmacological preconditioning using the immune activator D192935.

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Ischemia-reperfusion brain injury can be iatrogenically induced secondary to life-saving procedures. Prophylactic treatment of these patients offers a promising prevention for lifelong complications. We postulate that a cytosine-guanine (CpG) oligodeoxynucleotide (ODN) can provide robust antecedent protection against cerebral ischemic injury with minimal release of pro-inflammatory cytokines, making it an ideal candidate for further clinical development.

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Treatment with ipilimumab improves overall survival (OS) in patients with metastatic melanoma. Because ipilimumab targets T lymphocytes and not the tumor itself, efficacy may be uniquely sensitive to immunomodulatory factors present at the time of treatment. We analyzed serum from patients with metastatic melanoma (247 of 273, 90.

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Background And Purpose: Preconditioning with poly-l-lysine and carboxymethylcellulose (ICLC) provides robust neuroprotection from cerebral ischemia in a mouse stroke model. However, the receptor that mediates neuroprotection is unknown. As a synthetic double-stranded RNA, poly-ICLC may bind endosomal Toll-like receptor 3 or one of the cytosolic retinoic acid-inducible gene-I-like receptor family members, retinoic acid-inducible gene-I, or melanoma differentiation-associated protein 5.

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The use of accelerometry to monitor activity in human stroke patients has revealed strong correlations between objective activity measurements and subjective neurological findings. The goal of our study was to assess the applicability of accelerometry-based measurements in experimental animals undergoing surgically-induced cerebral ischemia. Using a nonhuman primate cortical stroke model, we demonstrate for the first time that monitoring locomotor activity prior to and following cerebrovascular ischemic injury using an accelerometer is feasible in adult male rhesus macaques and that the measured activity outcomes significantly correlate with severity of brain injury.

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Efforts to treat cardiovascular and cerebrovascular diseases often focus on the mitigation of ischemia-reperfusion (I/R) injury. Many treatments or "preconditioners" are known to provide substantial protection against the I/R injury when administered prior to the event. Brief periods of ischemia itself have been validated as a means to achieve neuroprotection in many experimental disease settings, in multiple organ systems, and in multiple species suggesting a common pathway leading to tolerance.

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Preconditioning with a low dose of harmful stimulus prior to injury induces tolerance to a subsequent ischemic challenge resulting in neuroprotection against stroke. Experimental models of preconditioning primarily focus on neurons as the cellular target of cerebral protection, while less attention has been paid to the cerebrovascular compartment, whose role in the pathogenesis of ischemic brain injury is crucial. We have shown that preconditioning with polyinosinic polycytidylic acid (poly-ICLC) protects against cerebral ischemic damage.

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Systemic preconditioning with the TLR9 ligand CpG induces neuroprotection against brain ischemic injury through a tumor necrosis factor (TNF)-dependent mechanism. It is unclear how systemic administration of CpG engages the brain to induce the protective phenotype. To address this, we created TLR9-deficient reciprocal bone marrow chimeric mice lacking TLR9 on either hematopoietic cells or radiation-resistant cells of nonhematopoietic origin.

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Preconditioning induces ischemic tolerance, which confers robust protection against ischemic damage. We show marked protection with polyinosinic polycytidylic acid (poly-IC) preconditioning in three models of murine ischemia-reperfusion injury. Poly-IC preconditioning induced protection against ischemia modeled in vitro in brain cortical cells and in vivo in models of brain ischemia and renal ischemia.

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Cerebral ischemic injury is a significant portion of the burden of disease in developed countries; rates of mortality are high and the costs associated with morbidity are enormous. Recent therapeutic approaches have aimed at mitigating the extent of damage and/or promoting repair once injury has occurred. Often, patients at high risk of ischemic injury can be identified in advance and targeted for antecedent neuroprotective therapy.

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Objective: Spleen tyrosine kinase (Syk) is involved in membrane-mediated signaling in various cells, including immune cells. It is overexpressed in T cells from patients with systemic lupus erythematosus (SLE), and its inhibition has been shown to improve T cell function as well as to improve disease manifestations in (NZB x NZW)F(1) lupus-prone mice and in patients with rheumatoid arthritis. While clinical trials examining Syk inhibition in patients with SLE are being considered, the aim of our experiments was to determine whether the therapeutic effects of Syk inhibition extend to other strains of lupus-prone mice and whether they result in improvement in skin disease and modification of established disease.

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Objective: To assess whether R788, an orally bioavailable small molecule inhibitor of spleen tyrosine kinase (Syk)-dependent signaling, could modulate disease in lupus-prone (NZB x NZW)F1 (NZB/NZW) mice via inhibition of Fc receptor (FcR) and B cell receptor signaling.

Methods: R788 was administered to NZB/NZW mice before and after disease onset. Proteinuria, blood urea nitrogen levels, and autoantibody titers were examined periodically, and overall survival and renal pathologic features were assessed following long-term treatment (24-34 weeks).

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Dendritic cells (DCs) play a key role in the interface between the innate and acquired immune systems. In response to both exogenous as well as endogenous signals, DCs undergo a programmed maturation to become an efficient, antigen-presenting cell. Yet little is known regarding the differential responses by endogenous versus exogenous stimuli on DC maturation.

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Control of dendritic cell (DC) function is critical for strategies to modulate innate and acquired immune responses. We examined whether transduction of murine DCs with adenoviral vectors (Adv) expressing interleukin (IL)-10 could alter their phenotype and T cell stimulatory function. Murine bone marrow-derived DCs were transduced with AdV encoding human IL-10 or green fluorescent protein (GFP).

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Adenovirus-based gene therapy offers a unique opportunity to target gene expression to the liver by systemic delivery. However, systemic administration of a first generation adenoviral construct elicits an inflammatory response leading to TNF-alpha-dependent liver injury. The aim of this study was to evaluate whether the systemic administration of recombinant adenovirus exacerbates a subsequent TNF-alpha-dependent liver injury induced by D-galactosamine and lipopolysaccharide.

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Dendritic cells (DCs) play a key role in critical illness and are depleted in spleens from septic patients and mice. To date, few studies have characterized the systemic effect of sepsis on DC populations in lymphoid tissues. We analyzed the phenotype of DCs and Th cells present in the local (mesenteric) and distant (inguinal and popliteal) lymph nodes of mice with induced polymicrobial sepsis (cecal ligation and puncture).

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The purpose of this study was to evaluate the ability to induce TNFalpha-dependent apoptosis in vivo in predisease lupus-prone NZM2410 and derived B6.NZM congenic mouse strains. An endotoxicosis model that utilizes LPS and d-galactosamine to induce mortality by TNFalpha/TNFR1-dependent hepatocyte apoptosis was used to assess TNFalpha production, apoptotic signaling, and effects on the production of IL-6 and IL-10.

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The functioning of the immune system is finely balanced by the activities of pro-inflammatory and anti-inflammatory mediators or cytokines. Unregulated activities of these mediators can lead to the development of serious inflammatory diseases. In particular, enhanced tumour-necrosis factor-alpha (TNF-alpha) synthesis is associated with the development of rheumatoid arthritis, psoriatic arthritis and inflammatory bowel disease.

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The dendritic cell (DC) is the most potent APC of the immune system, capable of stimulating naive T cells to proliferate and differentiate into effector T cells. Recombinant adenovirus (Adv) readily transduces DCs in vitro allowing directed delivery of transgenes that modify DC function and immune responses. In this study we demonstrate that footpad injection of a recombinant Adv readily targets transduction of myeloid and lymphoid DCs in the draining popliteal lymph node, but not in other lymphoid organs.

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