Gregory A Dekaban

Robarts Research Institute, London, Ontario, Canada

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Publications (46)182.5 Total impact

  • Article: Tracking and evaluation of dendritic cell migration by cellular magnetic resonance imaging.
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    ABSTRACT: Cellular magnetic resonance imaging (MRI) is a means by which cells labeled ex vivo with a contrast agent can be detected and tracked over time in vivo. This technology provides a noninvasive method with which to assess cell-based therapies in vivo. Dendritic cell (DC)-based vaccines are a promising cancer immunotherapy, but its success is highly dependent on the injected DC migrating to a secondary lymphoid organ such as a nearby lymph node. There the DC can interact with T cells to elicit a tumor-specific immune response. It is important to verify DC migration in vivo using a noninvasive imaging modality, such as cellular MRI, so that important information regarding the anatomical location and persistence of the injected DC in a targeted lymph node can be provided. An understanding of DC biology is critical in ascertaining how to label DC with sufficient contrast agent to render them detectable by MRI. While iron oxide nanoparticles provide the best sensitivity for detection of DC in vivo, a clinical grade iron oxide agent is not currently available. A clinical grade (19) Fluorine-based perfluorcarbon nanoemulsion is available but is less sensitive, and its utility to detect DC migration in humans remains to be demonstrated using clinical scanners presently available. The ability to quantitatively track DC migration in vivo can provide important information as to whether different DC maturation and activation protocols result in improved DC migration efficiency which will determine the vaccine's immunogenicity and ultimately the tumor immunotherapy's outcome in humans. WIREs Nanomed Nanobiotechnol 2013. doi: 10.1002/wnan.1227 For further resources related to this article, please visit the WIREs website.
    Wiley Interdisciplinary Reviews Nanomedicine and Nanobiotechnology 04/2013; · 5.19 Impact Factor
  • Article: Differential detection and distribution of microglial and hematogenous macrophage populations in the injured spinal cord of lys-EGFP-ki transgenic mice.
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    ABSTRACT: The acute inflammatory response that follows spinal cord injury (SCI) contributes to secondary injury that results in the expansion of the lesion and further loss of neurologic function. A cascade of receptor-mediated signaling events after SCI leads to activation of innate immune responses including the migration of microglia and active recruitment of circulating leukocytes. Because conventional techniques do not always distinguish macrophages derived from CNS-resident microglia from blood-derived monocytes, the role that each macrophage type performs cannot be assessed unambiguously in these processes. We demonstrate that, in the normal and spinal cord-injured lys-EGFP-ki transgenic mouse, enhanced green fluorescent protein (EGFP) is expressed only in mature hematopoietic granulomyelomonocytic cells and not in microglia. This allowed us to assess the temporal and spatial relationships between microglia-derived and hematogenous macrophages as well as neutrophils during a period of 6 weeks after clip compression SCI. Within the lesion, EGFP-positive monocyte-derived macrophages were found at the epicenter surrounded by EGFP-negative-activated microglia and microglia-derived macrophages. Neutrophils were not present when EGFP-positive monocyte-derived macrophages were depleted, indicating that neutrophil persistence in the lesion depended on the presence of these monocytes. Thus, these 2 distinct macrophage populations can be independently identified and tracked, thereby allowing their roles in acute and chronic stages of SCI-associated inflammation to be defined.
    Journal of Neuropathology and Experimental Neurology 03/2012; 71(3):180-97. · 4.26 Impact Factor
  • Article: Cellular MRI as a suitable, sensitive non-invasive modality for correlating in vivo migratory efficiencies of different dendritic cell populations with subsequent immunological outcomes.
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    ABSTRACT: The clinical application of dendritic cells (DC) as adjuvants in immunotherapies such as the cell-based cancer vaccine continues to gain interest. The overall efficacy of this emerging immunotherapy, however, remains low. Studies suggest the stage of maturation and activation of ex vivo-prepared DC immediately prior to patient administration is critical to subsequent DC migration in vivo, which ultimately affects overall vaccine efficacy. While it is possible to generate mature and activated DC ex vivo using various stimulatory cocktails, in the case of cancer patients, the qualitative and quantitative assessment of which DC stimulatory cocktail works most effectively to enhance subsequent DC migration in vivo is difficult. Thus, a non-invasive imaging modality capable of monitoring the real-time migration of DC in long-term studies is required. In this paper, we address whether cellular magnetic resonance imaging (MRI) is sufficiently sensitive to quantitatively detect differences in the migratory abilities of two different DC preparations: untreated (resting) versus ex vivo matured in a mouse model. In order to distinguish our ex vivo-generated DC of interest from surrounding tissues in magnetic resonance (MR) images, DC were labeled in vitro with the superparamagnetic iron oxide (SPIO) nanoparticle FeREX®. Characterization of DC phenotype and function following addition of a cytokine maturation cocktail and the toll-like receptor ligand CpG, both in the presence and in the absence of SPIO, were also carried out. Conventional histological techniques were used to verify the quantitative data obtained from MR images. This study provides important information relevant to tracking the in vivo migration of ex vivo-prepared and stimulated DC.
    International Immunology 01/2012; 24(1):29-41. · 3.41 Impact Factor
  • Article: Anti-CD11d monoclonal antibody treatment for rat spinal cord compression injury.
    Lynne C Weaver, Gregory A Dekaban, Arthur Brown
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    ABSTRACT: This paper by Hurtado et al. examined responses of spinal cord-injured rats to treatment with a monoclonal antibody to the CD11d integrin, as a replication study of the paper by Gris et al. published in J. Neuroscience, 2004. The Hurtado et al. study addressed a portion of our investigation and obtained similar findings in the experiments that closely replicated ours in methodology and design, specifically the open field locomotor study. The high variability in their study of mechanical allodynia probably precluded detection of effects of the anti-CD11d treatment on this form of neuropathic pain. The lesion assessments were greatly different from those done in the Gris et al. study, and may not have been ideal for the extent of injury produced in this model, but did reveal a trend toward myelin preservation. The positive aspects of the study by Hurtado et al. encourage us to investigate this novel treatment further, in different animals and in different models of spinal cord injury.
    Experimental Neurology 11/2011; 233(2):612-4. · 4.70 Impact Factor
  • Article: CD11d Antibody Treatment Improves Recovery in Spinal Cord-Injured Mice.
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    ABSTRACT: Acute administration of a monoclonal antibody (mAb) raised against the CD11d subunit of the leukocyte CD11d/CD18 integrin after spinal cord injury (SCI) in the rat greatly improves neurological outcomes. This has been chiefly attributed to the reduced infiltration of neutrophils into the injured spinal cord in treated rats. More recently, treating spinal cord-injured mice with a Ly-6G neutrophil-depleting antibody was demonstrated to impair neurological recovery. These disparate results could be due to different mechanisms of action utilized by the two antibodies, or due to differences in the inflammatory responses between mouse and rat that are triggered by SCI. To address whether the anti-CD11d treatment would be effective in mice, a CD11d mAb (205C) or a control mAb (1B7) was administered intravenously at 2, 24, and 48 h after an 8-g clip compression injury at the fourth thoracic spinal segment. The anti-CD11d treatment reduced neutrophil infiltration into the injured mouse spinal cord and was associated with increased white matter sparing and reductions in myeloperoxidase (MPO) activity, reactive oxygen species, lipid peroxidation, and scar formation. These improvements in the injured spinal cord microenvironment were accompanied by increased serotonin (5-HT) immunoreactivity below the level of the lesion and improved locomotor recovery. Our results with the 205C CD11d mAb treatment complement previous work using this anti-integrin treatment in a rat model of SCI.
    Journal of neurotrauma 11/2011; 29(3):539-50. · 4.25 Impact Factor
  • Article: Cellular magnetic resonance imaging of monocyte-derived dendritic cell migration from healthy donors and cancer patients as assessed in a scid mouse model.
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    ABSTRACT: BACKGROUND AIMS. The use of dendritic cells (DC) as an adjuvant in cell-based immunotherapeutic cancer vaccines is a growing field of interest. A reliable and non-invasive method to track the fate of autologous DC following their administration to patients is required in order to confirm that clinically sufficient numbers are reaching the lymph node (LN). We demonstrate that an immunocompromised mouse model can be used to conduct translational studies employing cellular magnetic resonance imaging (MRI). Such studies can provide clinically relevant information regarding the migration potential of clinical-grade DC used in cancer immunotherapies. METHODS. Human monocyte-derived dendritic cells (mo-DC) were generated from negatively selected monocytes obtained from either healthy donors or cancer patients. DC were labeled with superparamagnetic iron oxide (SPIO) nanoparticles in order to track them in vivo in a CB17scid mouse model using cellular MRI. SPIO did not have any adverse effects on DC phenotype or function, independent of donor type. Cellular MRI readily detected migration of SPIO-loaded DC in CB17scid mice. No differences in migration were observed between DC obtained from healthy donors and those obtained from donors undergoing autologous stem cell transplant for cancer therapy. CONCLUSIONS. Cellular MRI provided semi-quantitative image data that corresponded with data obtained by digital morphometry, validating cellular MRI's potential to assess DC migration in DC-based cancer immunotherapy clinical trials.
    Cytotherapy 09/2011; 13(10):1234-48. · 3.63 Impact Factor
  • Article: In vivo cellular MRI of dendritic cell migration using micrometer-sized iron oxide (MPIO) particles.
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    ABSTRACT: This study seeks to assess the use of labeling with micron-sized iron oxide (MPIO) particles for the detection and quantification of the migration of dendritic cells (DCs) using cellular magnetic resonance imaging (MRI). DCs were labeled with red fluorescent MPIO particles for detection by cellular MRI and a green fluorescent membrane dye (PKH67) for histological detection. MPIO-labeled DCs or unlabeled control DCs were injected into mice footpads at two doses (0.1 × 10(6) and 1 × 10(6)). Images were acquired at 3 Tesla before DC injection and 2, 3, and 7 days post-DC injection. Labeling DCs with MPIO particles did not affect viability, but it did alter markers of DC activation and maturation. MRI and fluorescence microscopy allowed for the detection of MPIO-labeled DCs within the draining popliteal nodes after their injection into the footpad. This paper presents the first report of the successful use of fluorescent MPIO particles to label and track DC migration.
    Molecular imaging and biology: MIB: the official publication of the Academy of Molecular Imaging 08/2011; 13(4):679-94. · 2.47 Impact Factor
  • Article: CD11d integrin blockade reduces the systemic inflammatory response syndrome after spinal cord injury.
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    ABSTRACT: Traumatic injury to the spinal cord triggers a systemic inflammatory response syndrome (SIRS), in which inflammatory cells from the circulation invade organs such as the liver, lung and kidney, leading to damage of these organs. Our previous study (Gris, et al, Exp. Neurol, 2008) demonstrated that spinal cord injury (SCI) activates circulating neutrophils that then invade the lung and kidney from 2 to 24 h after injury, increasing myeloperoxidase activity, cyclooxygenase-2 and matrix metalloproteinase-9 expression and lipid peroxidation in these organs. The present study was designed to ascertain whether a treatment that limits the influx of leukocytes into the injured spinal cord would also be effective in reducing the SIRS after SCI. This treatment is intravenous delivery of a monoclonal antibody (mAb) against the CD11d subunit of the CD11d/CD18 integrin expressed by neutrophils and monocytes. We delivered the anti-CD11d mAb at 2 h post moderate clip compression SCI at the 4th or 12th thoracic segments and assessed inflammation, oxidative activity and cellular damage within the lung, kidney and liver at 12 h post-injury. In some analyses we compared high and low thoracic injuries to evaluate the importance of injury level on the intensity of the SIRS. After T4 injury, treatment with the anti-integrin mAb reduced the presence of neutrophils and macrophages in the lung, with associated decreases in expression of NF-κB and oxidative enzymes and in the concentration of free radicals in this organ. The treatment also reduced lipid peroxidation, protein nitration and cell death in the lung. The anti-CD11d treatment also reduced the inflammatory cells within the kidney after T4 injury, as well as the free radical concentration and amount of lipid peroxidation. In the liver, the mAb treatment reduced the influx of neutrophils but most of the other measures examined were unaffected by SCI. The inflammatory responses within the lung and kidney were often greater after T4 than T12 injury. Clinical studies show that SIRS, with its associated organ failure, contributes significantly to the morbidity and mortality of SCI patients. This anti-integrin treatment may block the onset of SIRS after SCI.
    Experimental Neurology 07/2011; 231(2):272-83. · 4.70 Impact Factor
  • Article: Labelling dendritic cells with SPIO has implications for their subsequent in vivo migration as assessed with cellular MRI.
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    ABSTRACT: An optimized non-invasive imaging modality capable of tracking and quantifying in vivo DC migration in patients would provide clinicians with valuable information regarding therapeutic DC-based vaccine outcomes. Superparamagnetic iron oxide (SPIO) nanoparticles were used to label bone marrow-derived DC. In vivo DC migration was tracked and quantified non-invasively using cellular magnetic resonance imaging (MRI) in a mouse model. Labelling DC with SPIO reflects the kinetics of DC migration in vivo but appears to reduce overall DC migration, in part due to nanoparticle size. Magnetic separation of SPIO-labelled (SPIO(+)) DC from unlabelled (SPIO(-)) DC prior to injection improves SPIO(+) DC migration to the lymph node. Corresponding MR image data better correlate with the presence of DC in vivo; an improved immunological response is also seen. Cellular MRI is a viable, non-invasive imaging tool that can routinely track DC migration in vivo. Consideration should be given to optimizing MRI contrast agent-labelling of clinical-grade DC in order to accurately correlate DC fate to immunological outcomes in patients.
    Contrast Media & Molecular Imaging 07/2011; 6(4):314-27. · 3.33 Impact Factor
  • Article: Human spinal cord injury causes specific increases in surface expression of β integrins on leukocytes.
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    ABSTRACT: Spinal cord injury (SCI) activates circulating leukocytes that migrate into the injured cord and bystander organs using adhesion molecule-mediated mechanisms. These cells cause oxidative damage, resulting in secondary injury to the spinal cord, as well as injury to bystander organs. This study was designed to examine, over a 6-h to 2-week period, changes in adhesion molecule surface expression on human peripheral leukocytes after SCI (9 subjects), using as controls 10 uninjured subjects and 6 general trauma patients (trauma controls, TC). Both the percentage of cells expressing a given adhesion molecule and the average level of its expression was quantified for both circulating neutrophils and monocytes. The percentage of neutrophils and monocytes expressing the selectin CD62L was unchanged in TC and SCI patients after injury compared to uninjured subjects. Concurrently, the amount of surface CD62L on neutrophils was decreased in SCI and TC subjects, and on monocytes after SCI. The percentage of neutrophils expressing α4 decreased in TC, but not in SCI, subjects. Likewise, the percentage of neutrophils and monocytes expressing CD11d decreased markedly in TC subjects, but not after SCI. In contrast, the mean surface expression of α4 and CD11d by neutrophils and monocytes increased after SCI compared with uninjured and TC subjects. The percentage of cells and surface expression of CD11b were similar in neutrophils of all three groups, whereas CD11b surface expression increased after SCI in monocytes. In summary, unlike changes found after general trauma, the proinflammatory stimulation induced by SCI increases the surface expression of adhesion molecules on circulating neutrophils and monocytes before they infiltrate the injured spinal cord and multiple organs of patients. Integrins may be excellent targets for anti-inflammatory treatment after human SCI.
    Journal of neurotrauma 02/2011; 28(2):269-80. · 4.25 Impact Factor
  • Chapter: Assessing Immunotherapy Through Cellular and Molecular Imaging
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    ABSTRACT: Molecular medicine is focusing its attention on developing immunotherapeutic strategies that engage the immune system to combat a number of human diseases, including cancer. As a result, great emphasis has been placed on enhancing existing imaging modalities and developing new imaging techniques in order to assess the in vivo consequences of a given immunotherapy. Recently, improvements in the resolution and sensitivity of existing in vivo imaging modalities, including computed tomography (CT), ultrasound (US), positron emission tomography (PET), single positron emission tomography (SPECT), optical imaging (OI), and magnetic resonance imaging (MRI), have evolved enormously. In this chapter, each modality, used either individually or together as multi-modal hybrid imaging techniques, will be evaluated in the context of how they contribute to assessing immunotherapies in vivo in preclinical and clinical settings. KeywordsCT-MRI-Multi-modal imaging-Optical imaging-PET-Ultrasound
    12/2010: pages 389-408;
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    Article: Dendritic cell internalization of foam-structured fluorescent mesoporous silica nanoparticles.
    Abdul M Mumin, John W Barrett, Gregory A Dekaban, Jin Zhang
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    ABSTRACT: In this paper, foam-structured fluorescent mesoporous silica nanoparticles (FMSNs) are produced in a sol-gel method with the introduction of a phosphonate functional group. It is found that the phosphonate functionalized FMSNs with the foam structure minimizes the aggregation of FMSNs in solution. The average particle size of the FMSNs without and with phosphonate functionalization is 46.3 ± 5 nm and 60.5 ± 8 nm in diameter, respectively. The latter one exhibits higher fluorophore loading capacity (~67 ± 2.5%). The excitation wavelength (λ(ex)) of FMSNs is observed at 526 nm, approximate 12 nm larger in the Stoke-shift compared to the free organic dye at 494/514 nm. Furthermore, the photostability of the hydrophobic fluorophore is greatly improved by the FMSNs with the foam structure. In addition, the dose-dependent nature of FMSN uptake is assessed for the immune cells, the bone marrow-derived dendritic immune cells (BMDCs). Our results indicate that approximately 42% of BMDCs are able to take up foam-structured FMSNs (>5 μg/ml) without decreasing the viability of BMDCs. Thus, the phosphonate functionalized FMSNs with the foam structure are suitable to be used for many biomedical applications, especially in cell tracking.
    Journal of Colloid and Interface Science 09/2010; 353(1):156-62. · 3.07 Impact Factor
  • Article: Pathogenic antibodies are active participants in spinal cord injury.
    Gregory A Dekaban, Sakina Thawer
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    ABSTRACT: The role of B cells and autoimmunity as contributing factors to poor neurological outcomes following spinal cord injury (SCI) is poorly understood. The study by Ankeny et al., in this issue of the JCI, identifies a new immunopathological mechanism arising after SCI in mice (see the related article beginning on page 2990). The study shows that B cells produce pathogenic antibodies that impair lesion repair, resulting in worse neurological outcome. This new understanding of SCI disease pathogenesis, if confirmed in humans, reveals potential avenues for the development of novel neuroprotective immunotherapies.
    The Journal of clinical investigation 09/2009; 119(10):2881-4. · 15.39 Impact Factor
  • Article: The extracellular domain of CD11d regulates its cell surface expression.
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    ABSTRACT: A mAb targeting the CD11d subunit of the leukocyte integrin CD11d/CD18 decreases intraspinal inflammation and oxidative damage leading to improved neurological outcomes in rodent models of SCI. CD11d/CD18 is the fourth member of the beta2-integrin family. Current evidence indicates that CD11d/CD18 is regulated differently than other beta2-integrins, suggesting that CD11d(+) leukocytes play a distinct role in inflammation. Although the transcriptional control of CD11d expression has been evaluated, control of the intracellular distribution of CD11d has not been addressed. For this reason and as a result of the potential of CD11d as a therapeutic target for SCI and possibly other CNS injuries, we investigated the intracellular localization and surface expression of CD11d in cultured cells. CD11d and CD18 were fused at their C-termini with YFP and mRFP, respectively. Flow cytometry and confocal microscopy demonstrated that rCD11d-YFP is expressed on the cell surface of leukocyte cell lines expressing CD18. In contrast, in heterologous cell lines, CD11d-YFP is retained intracellularly in the TGN. Coexpression of CD11d-YFP and CD18-mRFP relieves this intracellular restriction and allows the CD11d/CD18 heterodimer to be surface-expressed. Based on domain-swapping experiments with CD25, the extracellular domain of CD11d is required and sufficient for the observed intracellular retention in heterologous cells. Furthermore, the transmembrane and C-terminus are also required for proper heterodimerization with CD18 and localization to the plasma membrane. These findings suggest that multiple CD11d domains play a role in controlling intracellular location and association with CD18.
    Journal of leukocyte biology 08/2009; 86(4):851-62. · 4.99 Impact Factor
  • Article: Myxoma virus M130R is a novel virulence factor required for lethal myxomatosis in rabbits.
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    ABSTRACT: Myxoma virus (MV) is a highly lethal, rabbit-specific poxvirus that induces a disease called myxomatosis in European rabbits. In an effort to understand the function of predicted immunomodulatory genes we have deleted various viral genes from MV and tested the ability of these knockout viruses to induce lethal myxomatosis. MV encodes a unique 15 kD cytoplasmic protein (M130R) that is expressed late (12h post infection) during infection. M130R is a non-essential gene for MV replication in rabbit, monkey or human cell lines. Construction of a targeted gene knockout virus (vMyx130KO) and infection of susceptible rabbits demonstrate that the M130R knockout virus is attenuated and that loss of M130R expression allows the rabbit host immune system to effectively respond to and control the lethal effects of MV. M130R expression is a bona fide poxviral virulence factor necessary for full and lethal development of myxomatosis.
    Virus Research 06/2009; 144(1-2):258-65. · 2.94 Impact Factor
  • Article: Induction of alpha/beta interferon by myxoma virus is selectively abrogated when primary mouse embryo fibroblasts become immortalized.
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    ABSTRACT: Mouse embryo fibroblasts (MEFs) are a widely used cell culture system in life sciences, including virology. Here, we show that although primary MEFs are nonpermissive to myxoma virus replication, the corresponding immortalized MEFs support a highly productive myxoma virus infection. We further demonstrate that this permissive phenotype for myxoma virus in immortalized MEFs is due to the immortalization-associated selective block to the cellular alpha/beta interferon induction machinery involved in responding to myxoma virus challenge. Thus, our report presents a clear example, illustrating that a drastic phenotypic alteration can occur with respect to virus infection between primary cells and their immortalized counterparts.
    Journal of Virology 04/2009; 83(11):5928-32. · 5.40 Impact Factor
  • Article: Gene expression profiling in anti-CD11d mAb-treated spinal cord-injured rats.
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    ABSTRACT: Acute administration of a mononclonal antibody (mAb) raised against the CD11d subunit of the leukocyte CD11d/CD18 integrin after spinal cord injury (SCI) in the rat greatly improves neurological outcomes. We have profiled gene expression in anti-CD11d and isotyped-matched control mAb-treated rats after SCI. Microarray analysis demonstrated reduced expression of pro-inflammatory cytokines and increased expression of inflammatory mediators that promote wound healing and the expression of scar proteins predicted to improve nerve growth. These changes in gene expression may reflect changes in the types of macrophages that populate the lesions in anti-CD11d mAb-treated rats.
    Journal of neuroimmunology 03/2009; 209(1-2):104-13. · 2.84 Impact Factor
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    Article: RIG-I mediates the co-induction of tumor necrosis factor and type I interferon elicited by myxoma virus in primary human macrophages.
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    ABSTRACT: The sensing of pathogen infection and subsequent triggering of innate immunity are key to controlling zoonotic infections. Myxoma virus (MV) is a cytoplasmic DNA poxvirus that in nature infects only rabbits. Our previous studies have shown that MV infection of primary mouse cells is restricted by virus-induced type I interferon (IFN). However, little is known about the innate sensor(s) involved in activating signaling pathways leading to cellular defense responses in primary human immune cells. Here, we show that the complete restriction of MV infection in the primary human fibroblasts requires both tumor necrosis factor (TNF) and type I IFN. We also demonstrate that MV infection of primary human macrophages (pHMs) activates the cytoplasmic RNA sensor called retinoic acid inducible gene I (RIG-I), which coordinately induces the production of both TNF and type I IFN. Of note, RIG-I sensing of MV infection in pHMs initiates a sustained TNF induction through the sequential involvement of the downstream IFN-regulatory factors 3 and 7 (IRF3 and IRF7). Thus, RIG-I-mediated co-induction of TNF and type I IFN by virus-infected pHMs represents a novel innate defense mechanism to restrict viral infection in human cells. These results also reveal a new regulatory mechanism for TNF induction following viral infection.
    PLoS Pathogens 08/2008; 4(7):e1000099. · 9.13 Impact Factor
  • Article: Inclusion of the viral anti-apoptotic molecule M11L in DNA vaccine vectors enhances HIV Env-specific T cell-mediated immunity.
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    ABSTRACT: A current goal of vaccine development against human immunodeficiency virus (HIV) is to develop a strategy that stimulates long-lasting memory T-cell responses, and provides immediate cytotoxicity in response to viral challenge. We demonstrate that the viral antiapoptotic molecule M11L promotes cellular immune responses to the HIV envelope protein. Coexpression of M11L in vitro inhibits gp140-mediated apoptosis and increases gp140 expression levels. Mice primed with M11L-pHERO DNA, followed by vCP205 boosting, exhibit significantly greater HIV-specific T-cell responses. Moreover, M11L synergizes with CpG motifs to augment anti-HIV responses and stimulates robust expansion of central memory and effector memory CD8(+) T-cells. Inclusion of M11L in a DNA vector increases the magnitude of T-cell responses, and promotes the generation of memory T-cells that provide rapid-responding CTL responses. This vaccine strategy may facilitate the generation of an efficacious vaccine for HIV, and other chronic diseases that require enhanced cell-mediated immunity, including HCV and metastatic cancer.
    Virology 06/2008; 375(1):48-58. · 3.35 Impact Factor
  • Article: Transient blockage of the CD11d/CD18 integrin reduces contusion volume and macrophage infiltration after traumatic brain injury in rats.
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    ABSTRACT: The early inflammatory response to traumatic brain injury (TBI) may result in secondary damage. The purpose of this study was to evaluate the effects of a transient treatment employing a blocking monoclonal antibody (mAb) to the CD11d/CD18 integrin on histopathological outcome and macrophage infiltration following TBI. A parasagittal fluid percussion (FP) brain injury (1.8-2.1 atm) was induced in male Sprague-Dawley rats. Rats were randomized into two trauma groups, treated (N=7) and nontreated (N=8) animals. In the treated group, a mAb to the CD11d subunit of the CD11d/CD18 integrin was administered 30 min, 24 and 48 h after brain injury. Control animals received an isotype-matched irrelevant mAb using the same dose and treatment regimen. At 3 days after TBI, animals were perfusion-fixed for histopathological and immunocytochemical analysis. The anti-CD11d mAb treatment reduced contusion areas as well as overall contusion volume compared to vehicle treated animals. For example, overall contusion volume was reduced from 2.7+/-0.5 mm(3) (mean+/-SEM) to 1.4+/-0.4 with treatment (p<0.05). Immunocytochemical studies identifying CD68 immunoreactive macrophages showed that treatment caused significant attenuation of leukocyte infiltration into the contused cortical areas. These data emphasize the beneficial effects of blocking inflammatory cell recruitment into the injured brain on histopathological outcome following traumatic brain injury.
    Brain Research 06/2008; 1207:155-63. · 2.73 Impact Factor