Michael I Nishimura

Loyola University Medical Center, Maywood, Illinois, United States

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Publications (80)445.23 Total impact

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    ABSTRACT: Ex vivo-expanded CD8+ T cells used for adoptive immunotherapy generally acquire an effector memory-like phenotype (TEM cells). With regard to therapeutic applications, two undesired features of this phenotype in vivo are limited persistence and reduced anti-tumor efficacy, relative to CD8+ T cells with a central memory-like phenotype (TCM cells). Further, there is incomplete knowledge about all the differences between TEM and TCM cells that may influence tumor treatment outcomes. Given that TCM cells survive relatively longer in oxidative tumor microenvironments, we investigated the hypothesis that TCM possess relatively greater anti-oxidative capacity than TEM cells. Here we report that TCM cells exhibit a relative increase compared to TEM cells in expression of cell surface thiols, a key target of cellular redox controls, along with other antioxidant molecules. Increased expression of redox regulators in TCM cells inversely correlated with the generation of reactive oxygen and nitrogen species, proliferative capacity and glycolytic enzyme levels. Notably, TCR-transduced T cells pretreated with thiol donors, such as N-acetyl cysteine or rapamycin, up-regulated thiol levels and antioxidant genes. A comparison of anti-tumor CD8+ T cell populations on the basis of surface thiol expression showed that thiol-high cells persisted longer in vivo and exerted superior tumor control. Our results suggest that higher levels of reduced cell surface thiols are a key characteristic of T cells that can control tumor growth, and that profiling this biomarker may have benefits to T cell adoptive immunotherapy protocols.
    Cancer research. 08/2014;
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    ABSTRACT: To generate a mouse model of spontaneous epidermal depigmentation, parental h3TA2 mice, expressing both a human-derived, tyrosinase-reactive T cell receptor on T cells and the matching HLA-A2 transgene, were crossed to keratin 14-promoter driven, stem cell factor transgenic (K14-SCF) mice with intra-epidermal melanocytes. In resulting Vitesse mice, spontaneous skin depigmentation precedes symmetrical and sharply demarcated patches of graying hair. Whereas the SCF transgene alone dictates a greater retinoic acid receptor-related orphan receptor gamma (RORγt)(+) T cell compartment, these cells displayed markedly increased IL-17 expression within Vitesse mice. Similar to patient skin, regulatory T cells were less abundant compared to K14-SCF mice, with the exception of gradually appearing patches of repigmenting skin. The subtle repigmentation observed likely reflects resilient melanocytes that co-exist with skin-infiltrating, melanocyte-reactive T cells. Similar repigmenting lesions were found in a different TCR transgenic model of vitiligo developed on an SCF transgenic background, supporting a role for SCF in repigmentation. This article is protected by copyright. All rights reserved.
    Pigment Cell & Melanoma Research 06/2014; · 5.84 Impact Factor
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    ABSTRACT: T cell cytolytic activity targeting epidermal melanocyte is shown to cause progressive depigmentation and autoimmune vitiligo. Using the recently developed transgenic mice h3TA2 that carry T cell with a HLA-A2 restricted human tyrosinase reactive TCR and develop spontaneous vitiligo from an early age, we addressed the mechanism regulating autoimmune vitiligo. Depigmentation was significantly impaired only in IFN-γ knockout h3TA2 mice but not in TNF-α or perforin knockout h3TA2 mouse strains, confirming a central role for IFN-γ in vitiligo development. Additionally, the regulatory T cells (Treg) were relatively abundant in h3TA2-IFN-γ(-/-) mice, and depletion of Treg employing anti-CD25 antibody fully restored the depigmentation phenotype in h3TA2-IFN-γ(-/-) mice mediated in part through upregulation of pro-inflammatory cytokines as IL-17and IL-22. Further therapeutic potential of Treg abundance in preventing progressive depigmentation was evaluated by adoptively transferring purified Treg or using rapamycin. Both adoptive transfer of Treg and rapamycin induced lasting remission of vitiligo in mice treated at the onset of disease, or in mice with established disease. This leads us to conclude that reduced regulatory responses are pivotal to the development of vitiligo in disease-prone mice, and that a quantitative increase in the Treg population may be therapeutic for vitiligo patients with active disease.Journal of Investigative Dermatology accepted article preview online, 23 December 2013. doi:10.1038/jid.2013.540.
    Journal of Investigative Dermatology 12/2013; · 6.19 Impact Factor
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    ABSTRACT: Vitiligo is an autoimmune disease characterized by destruction of melanocytes, leaving 0.5% of the population with progressive depigmentation. Current treatments offer limited efficacy. We report that modified inducible heat shock protein 70 (HSP70i) prevents T cell-mediated depigmentation. HSP70i is the molecular link between stress and the resultant immune response. We previously showed that HSP70i induces an inflammatory dendritic cell (DC) phenotype and is necessary for depigmentation in vitiligo mouse models. Here, we observed a similar DC inflammatory phenotype in vitiligo patients. In a mouse model of depigmentation, DNA vaccination with a melanocyte antigen and the carboxyl terminus of HSP70i was sufficient to drive autoimmunity. Mutational analysis of the HSP70i substrate-binding domain established the peptide QPGVLIQVYEG as invaluable for DC activation, and mutant HSP70i could not induce depigmentation. Moreover, mutant HSP70i bound human DCs and reduced their activation, as well as induced a shift from inflammatory to tolerogenic DCs in mice. HSP70i-encoding DNA applied months before spontaneous depigmentation prevented vitiligo in mice expressing a transgenic, melanocyte-reactive T cell receptor. Furthermore, use of HSP70i therapeutically in a different, rapidly depigmenting model after loss of differentiated melanocytes resulted in 76% recovery of pigmentation. Treatment also prevented relevant T cells from populating mouse skin. In addition, ex vivo treatment of human skin averted the disease-related shift from quiescent to effector T cell phenotype. Thus, HSP70i DNA delivery may offer potent treatment opportunities for vitiligo.
    Science translational medicine 02/2013; 5(174):174ra28. · 10.76 Impact Factor
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    ABSTRACT: Prediction of clinical outcome in cancer is usually achieved by histopathological evaluation of tissue samples obtained during surgical resection of the primary tumor. Traditional tumor staging (AJCC/UICC-TNM classification) summarizes data on tumor burden (T), presence of cancer cells in draining and regional lymph nodes (N) and evidence for metastases (M). However, it is now recognized that clinical outcome can significantly vary among patients within the same stage. The current classification provides limited prognostic information, and does not predict response to therapy. Recent literature has alluded to the importance of the host immune system in controlling tumor progression. Thus, evidence supports the notion to include immunological biomarkers, implemented as a tool for the prediction of prognosis and response to therapy. Accumulating data, collected from large cohorts of human cancers, has demonstrated the impact of immune-classification, which has a prognostic value that may add to the significance of the AJCC/UICC TNM-classification. It is therefore imperative to begin to incorporate the 'Immunoscore' into traditional classification, thus providing an essential prognostic and potentially predictive tool. Introduction of this parameter as a biomarker to classify cancers, as part of routine diagnostic and prognostic assessment of tumors, will facilitate clinical decision-making including rational stratification of patient treatment. Equally, the inherent complexity of quantitative immunohistochemistry, in conjunction with protocol variation across laboratories, analysis of different immune cell types, inconsistent region selection criteria, and variable ways to quantify immune infiltration, all underline the urgent requirement to reach assay harmonization. In an effort to promote the Immunoscore in routine clinical settings, an international task force was initiated. This review represents a follow-up of the announcement of this initiative, and of the J Transl Med. editorial from January 2012. Immunophenotyping of tumors may provide crucial novel prognostic information. The results of this international validation may result in the implementation of the Immunoscore as a new component for the classification of cancer, designated TNM-I (TNM-Immune).
    Journal of Translational Medicine 10/2012; 10(1):205. · 3.46 Impact Factor
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    ABSTRACT: Recent advancements in T cell immunotherapy suggest that T cells engineered with high-affinity TCR can offer better tumor regression. However, whether a high-affinity TCR alone is sufficient to control tumor growth, or the T cell subset bearing the TCR is also important remains unclear. Using the human tyrosinase epitope-reactive, CD8-independent, high-affinity TCR isolated from MHC class I-restricted CD4(+) T cells obtained from tumor-infiltrating lymphocytes (TIL) of a metastatic melanoma patient, we developed a novel TCR transgenic mouse with a C57BL/6 background. This HLA-A2-restricted TCR was positively selected on both CD4(+) and CD8(+) single-positive cells. However, when the TCR transgenic mouse was developed with a HLA-A2 background, the transgenic TCR was primarily expressed by CD3(+)CD4(-)CD8(-) double-negative T cells. TIL 1383I TCR transgenic CD4(+), CD8(+), and CD4(-)CD8(-) T cells were functional and retained the ability to control tumor growth without the need for vaccination or cytokine support in vivo. Furthermore, the HLA-A2(+)/human tyrosinase TCR double-transgenic mice developed spontaneous hair depigmentation and had visual defects that progressed with age. Our data show that the expression of the high-affinity TIL 1383I TCR alone in CD3(+) T cells is sufficient to control the growth of murine and human melanoma, and the presence or absence of CD4 and CD8 coreceptors had little effect on its functional capacity.
    The Journal of Immunology 07/2012; 189(4):1627-38. · 5.52 Impact Factor
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    ABSTRACT: Sonic hedgehog (SHh) signaling is important in the pathogenesis of various human cancers, such as medulloblastomas, and it has been identified as a valid target for anticancer therapeutics. The SHh inhibitor cyclopamine induces apoptosis. The bioactive sphingolipid ceramide mediates cell death in response to various chemotherapeutic agents; however, ceramide's roles/mechanisms in cyclopamine-induced apoptosis are unknown. Here, we report that cyclopamine mediates ceramide generation selectively via induction of neutral sphingomyelin phosphodiesterase 3, SMPD3 (nSMase2) in Daoy human medulloblastoma cells. Importantly, short interfering RNA-mediated knockdown of nSMase2 prevented cyclopamine-induced ceramide generation and protected Daoy cells from drug-induced apoptosis. Accordingly, ectopic wild-type N-SMase2 caused cell death, compared with controls, which express the catalytically inactive N-SMase2 mutant. Interestingly, knockdown of smoothened (Smo), a target protein for cyclopamine, or Gli1, a downstream signaling transcription factor of Smo, did not affect nSMase2. Mechanistically, our data showed that cyclopamine induced nSMase2 and cell death selectively via increased nitric oxide (NO) generation by neuronal-nitric oxide synthase (n-NOS) induction, in Daoy medulloblastoma, and multiple other human cancer cell lines. Knockdown of n-NOS prevented nSMase2 induction and cell death in response to cyclopamine. Accordingly, N-SMase2 activity-deficient skin fibroblasts isolated from homozygous fro/fro (fragilitas ossium) mice exhibited resistance to NO-induced cell death. Thus, our data suggest a novel off-target function of cyclopamine in inducing apoptosis, at least in part, by n-NOS/NO-dependent induction of N-SMase2/ceramide axis, independent of Smo/Gli inhibition.
    Molecular Cancer Therapeutics 03/2012; 11(5):1092-102. · 5.60 Impact Factor
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    ABSTRACT: In selected patients with chronic pancreatitis, total pancreatectomy with islet autotransplantation can be effective for the treatment of intractable pain while ameliorating postoperative diabetes. Improved quality of life scores and decreased daily narcotic use, as indicators of successful pain relief, are expected after total pancreatectomy. These outcomes and their relationship have not been well examined in this patient group. A prospectively collected database of patients undergoing extensive pancreatectomy with islet autotransplantation for pancreatitis was reviewed. Data pertaining to daily oral morphine equivalents (MEs) and quality of life (QOL), as measured by the SF-12 questionnaire, in the preoperative and postoperative period were reviewed. Approval from the IRB for the evaluation of human subjects was obtained. Over a 20-month period, 33 patients (25 women, median age 42) underwent extensive pancreatectomy with islet autotransplantation for pancreatitis. Mean follow-up was 9 months with a range of 6-12 months. Postoperative complications occurred in 16 patients (48%). Preoperative QOL scores were a mean 25 for physical component and 32 for mental health component. Postoperatively, physical component scores averaged 33 at 6 months (p = 0.025) and 36 at 12 months (mean increase of 11); the mental health component scores averaged 43 at 6 months (p = 0.007) and 44 at 12 months (mean increase of 12). Preoperative MEs averaged 357 mg daily. At discharge from the hospital, this number increased to 536 mg average MEs daily, a 50% increase, as expected after major surgery in the chronic pain patient. At 6 months, 15 out of 31 patients (48%) required less daily MEs than preoperatively and averaged 161 mg daily (-55%). By 12 months, 11 out of 17 patients (65%) required less daily MEs than preoperatively and averaged 128 mg daily (-64%); four were narcotic-free (23%). Of the six patients who did not decrease their analgesic requirements at 1 year, five (83%) still had an improved physical QOL score (one patient was unchanged) and all six had an improved mental health QOL. Total pancreatectomy with islet autotransplant is an effective surgery for end-stage chronic pancreatitis. Quality of life improves early postoperatively while decreased narcotic analgesia requirements occur later. Both improved quality of life and decreased narcotic analgesia requirements continue to occur at least up to 1 year postoperatively. Further investigation is needed to assess the durability of total pancreatectomy with islet autotransplantation for severe chronic pancreatitis with respect to pain relief and improved quality of life.
    Journal of Gastrointestinal Surgery 01/2012; 16(1):129-33; discussion 133-4. · 2.36 Impact Factor
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    ABSTRACT: Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer.
    Journal of Translational Medicine 12/2011; 9(1):214. · 3.46 Impact Factor
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    ABSTRACT: T-cell receptors (TCR) recognize complexes between human leukocyte antigens (HLA) and peptides derived from intracellular proteins. Their therapeutic use for antigen targeting, however, has been hindered by the very low binding affinity of TCRs, typically in the 1- to 100-μM range. Therefore, to construct mutant TCRs with high binding affinity, we need to understand the relationship between the structure and activity of these molecules. Here, we attempted to identify the amino acids of the TCR that are important for binding to the peptide/HLA complex. We used a TCR that recognizes complexes between HLA-A(∗)0201 and the peptide from tyrosinase, antigen overexpressed in melanoma. We changed 16 amino acids in the third complementarity-determining region within the TCR to alanine and examined the effect on binding affinity. Five alanine substitutions decreased the binding affinity to below 10% compared with that of wild-type TCR. In contrast, one alanine substitution caused a faster on-rate and slower off-rate, and increased the binding affinity to three times that of the wild-type TCR. Our results provide fundamental information for constructing mutant TCRs with high binding affinity.
    Biochemical and Biophysical Research Communications 10/2011; 415(4):558-62. · 2.41 Impact Factor
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    ABSTRACT: In selected patients with chronic pancreatitis, extensive pancreatectomy can be effective for the treatment of intractable pain. The resultant morbid diabetes can be ameliorated with islet autotransplantation (IAT). Conventionally, islet infusion occurs intraoperatively after islet processing. A percutaneous transhepatic route in the immediate postoperative period is an alternative approach. A prospectively collected database of patients undergoing pancreatectomy with percutaneous IAT (P-IAT) was reviewed. Hospital billing data were obtained and median charges determined and compared with estimated charges for an intraoperative infusion method of IAT (I-IAT). Thirty-six patients (28 women; median age 48 years) underwent pancreatectomy with P-IAT. Median operative time was 232 min (range: 98-395 min) and median estimated blood loss was 500 cc (range: 75-3000 cc). Median time from pancreatic resection to islet transplantation was 269 min (range: 145-361 min). A median of 208 248 IEq (2298 IEq/kg) were harvested. Median peak portal venous pressure during islet infusion was 13 mmHg (range: 5-37 mmHg). Postoperative complications occurred in 15 patients (42%) and included hepatic artery pseudoaneurysm and portal vein thrombosis; the latter occurred in two patients with portal pressures during infusion > 30 mmHg. At a median follow-up of 10.7 months, eight patients (22%) were insulin-free. Median pertinent charges for P-IAT were US$36,318 and estimated median charges for I-IAT were US$56,440. Surgeon time freed by P-IAT facilitated an additional 66 procedures, charges for which amounted to US$463,375. Percutaneous transhepatic IAT is feasible and safe. Islet infusion in the immediate postoperative period is cost-effective. Further follow-up is needed to assess longterm results.
    HPB 07/2011; 13(7):511-6. · 1.94 Impact Factor
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    ABSTRACT: CD8+ T cell function depends on a finely orchestrated balance of activation/suppression signals. While the stimulatory role of the CD8 co-receptor and pleiotropic capabilities of TGF-β have been studied individually, the influence of CD8 co-receptor on TGF-β function in CD8+ T cells is unknown. Here, we show that while CD8 enhances T cell activation, it also enhances susceptibility to TGF-β-mediated immune suppression. Using Jurkat cells expressing a full-length, truncated or no αβCD8 molecule, we demonstrate that cells expressing full-length αβCD8 were highly susceptible, αβCD8-truncated cells were partially susceptible, and CD8-deficient cells were completely resistant to suppression by TGF-β. Additionally, we determined that inhibition of Lck rendered mouse CD8+ T cells highly resistant to TGF-β suppression. Resistance was not associated with TGF-β receptor expression but did correlate with decreased Smad3 and increased Smad7 levels. These findings highlight a previously unrecognized third role for CD8 co-receptor which appears to prepare activated CD8+ T cells for response to TGF-β. Based on the important role which TGF-β-mediated suppression plays in tumor immunology, these findings unveil necessary considerations in formulation of CD8+ T cell-related cancer immunotherapy strategies.
    Cancer Immunology and Immunotherapy 02/2011; 60(2):291-7. · 3.64 Impact Factor
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    ABSTRACT: The HER2 oncogene is frequently over-expressed in human cancers and a promising target for immune therapy. Previous studies have shown that over-expression of mouse or rat HER2 leads to markedly reduced levels of major histocompatibility complex (MHC) class I and molecules of the antigen processing and presentation machinery (APM), thus resulting in a phenotype promoting tumor escape from the immune system. Our study focuses on analyzing the effect of HER2 on MHC class I antigen presentation and sensitivity to tumor-antigen specific cytotoxic T lymphocytes (CTLs) in HLA-A2.1(+) melanoma cell lines. We demonstrate significant inverse correlations both between the expression of HER2 and total MHC class I surface expression as well as between HER2 and HLA-A2. A significant reduction of HLA-A2 levels was found when melanoma and carcinoma cell lines were transfected with a human HER2 gene. A signaling-competent HER2 molecule was crucial for the observed HLA-A2 down-regulation, as transfectants expressing high levels of HER2 mutated in the tyrosine signaling domain did not show altered HLA-A2 expression. Importantly, the human melanoma cell line EST049 demonstrated reduced HER2 and melanoma antigen-specific recognition by CTLs upon HER2 transfection. In addition, high expression of HER2 prevented both IFN-γ mediated HLA-A2 up-regulation and improved recognition by HLA-A2-restricted CTLs in treated cells. Moreover, key APM molecules were down-regulated by HER2. These findings implicate that HER2 over-expressing tumors may be more prone to escape from HLA-A2 restricted CTLs suggesting that immunotherapy approaches inducing an integrated humoral, cellular and innate immune response would be most effective.
    International Journal of Cancer 01/2011; 128(2):390-401. · 6.20 Impact Factor
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    Amir A Al-Khami, Shikhar Mehrotra, Michael I Nishimura
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    ABSTRACT: Adoptive transfer of tumor-reactive T cells has emerged as a promising advance in tumor immunotherapy. Specifically, infusion of tumor-infiltrating lymphocytes has led to long-term objective clinical responses for patients with metastatic melanoma. Donor lymphocyte infusion is also an effective treatment of post-transplant lymphoproliferative disease. However, adoptive T cell therapy has restrictions in the isolation and expansion of antigen-specific lymphocytes for a large group of patients. One approach to circumvent this limitation and extend adoptive immunotherapy to other cancer types is the genetic modification of T cells with antigen-specific receptors. In this article, we review strategies to redirect T cell specificity, including T cell receptor gene transfer and antibody receptor gene transfer.
    Self/Nonself - Immune Recognition and Signaling 01/2011; 2(2):80-84.
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    ABSTRACT: Having successfully developed mechanisms to evade immune clearance, hepatitis C virus (HCV) establishes persistent infection in approximately 75%-80% of patients. In these individuals, the function of HCV-specific CD8+ T cells is impaired by ligation of inhibitory receptors, the repertoire of which has expanded considerably in the past few years. We hypothesized that the coexpression of the negative regulatory receptors T cell immunoglobulin and mucin domain-containing molecule 3 (Tim-3) and programmed death 1 (PD-1) in HCV infection would identify patients at risk of developing viral persistence during and after acute HCV infection. The frequency of PD-1-Tim-3- HCV-specific CTLs greatly outnumbered PD-1+Tim-3+ CTLs in patients with acute resolving infection. Moreover, the population of PD-1+Tim-3+ T cells was enriched for within the central memory T cell subset and within the liver. Blockade of either PD-1 or Tim-3 enhanced in vitro proliferation of HCV-specific CTLs to a similar extent, whereas cytotoxicity against a hepatocyte cell line that expressed cognate HCV epitopes was increased exclusively by Tim-3 blockade. These results indicate that the coexpression of these inhibitory molecules tracks with defective T cell responses and that anatomical differences might account for lack of immune control of persistent pathogens, which suggests their manipulation may represent a rational target for novel immunotherapeutic approaches.
    The Journal of clinical investigation 11/2010; 120(12):4546-57. · 15.39 Impact Factor
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    ABSTRACT: A key issue in advancing the use of adoptive cell transfer (ACT) of T cell receptor (TCR) engineered lymphocytes for cancer therapy is demonstrating how TCR transgenic cells repopulate lymphopenic hosts and target tumors in an antigen-specific fashion. ACT of splenocytes from fully immunocompetent HLA-A2.1/K(b) mice transduced with a chimeric murine/human TCR specific for tyrosinase, together with lymphodepletion conditioning, dendritic cell (DC)-based vaccination, and high-dose interleukin-2 (IL-2), had profound antitumor activity against large established MHC- and antigen-matched tumors. Genetic labeling with bioluminescence imaging (BLI) and positron emitting tomography (PET) reporter genes allowed visualization of the distribution and antigen-specific tumor homing of TCR transgenic T cells, with trafficking correlated with antitumor efficacy. After an initial brief stage of systemic distribution, TCR-redirected and genetically labeled T cells demonstrated an early pattern of specific distribution to antigen-matched tumors and locoregional lymph nodes, followed by a more promiscuous distribution 1 wk later with additional accumulation in antigen-mismatched tumors. This approach of TCR engineering and molecular imaging reporter gene labeling is directly translatable to humans and provides useful information on how to clinically develop this mode of therapy.
    Proceedings of the National Academy of Sciences 08/2010; 107(32):14286-91. · 9.81 Impact Factor
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    ABSTRACT: Objective clinical responses can be achieved in melanoma patients by infusion of T cell receptor (TCR) gene transduced T cells. Although promising, the therapy is still largely ineffective, as most patients did not benefit from treatment. That only a minority of the infused T cells were genetically modified and that these were extensively expanded ex vivo may have prevented their efficacy. We developed novel and generally applicable retroviral vectors that allow rapid and efficient selection of T cells transduced with human TCRs. These vectors encode two TCR chains and a truncated CD34 molecule (CD34t) in a single mRNA transcript. Transduced T cells were characterized and the effects of CD34-based enrichment of redirected T cells were evaluated. Both CD8(+) and CD4(+) T cells could be transduced and efficiently co-expressed all introduced transgenes on their surface. Importantly, more than fivefold enrichment of both the frequency of transduced cells and the specific anti-tumor reactivity of the effector population could be achieved by magnetic beads-based enrichment procedures readily available for clinical grade hematopoietic stem cell isolation. This CD34-based enrichment technology will improve the feasibility of adoptive transfer of clinically relevant effectors. In addition to their enhanced tumor recognition, the enriched redirected T cells may also show superior reactivity and persistence in vivo due to the high purity of transduced cells and the shortened ex vivo culture.
    Cancer Immunology and Immunotherapy 06/2010; 59(6):851-62. · 3.64 Impact Factor
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    ABSTRACT: In human vitiligo, cutaneous depigmentation involves cytotoxic activity of autoreactive T cells. It was hypothesized that depigmentation can progress in the absence of regulatory T cells (Treg). The percentage of Treg among skin infiltrating T cells was evaluated by immunoenzymatic double staining for CD3 and FoxP3, revealing drastically reduced numbers of Treg in non-lesional, perilesional and lesional vitiligo skin. Assessment of the circulating Treg pool by FACS analysis of CD4, CD25, CD127 and FoxP3 expression, and mixed lymphocyte reactions in presence and absence of sorted Treg revealed no systemic drop in the abundance or activity of Treg in vitiligo patients. Expression of skin homing receptors CCR4, CCR5, CCR8 and CLA was comparable among circulating vitiligo and control Treg. Treg from either source were equally capable of migrating towards CCR4 ligand and skin homing chemokine CCL22, yet significantly reduced expression of CCL22 in vitiligo skin observed by immunohistochemistry may explain failure of circulating, functional Treg to home to the skin in vitiligo. The paucity of Treg in vitiligo skin is likely crucial for perpetual anti-melanocyte reactivity in progressive disease.
    Pigment Cell & Melanoma Research 02/2010; 23(2):276-86. · 5.84 Impact Factor
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    ABSTRACT: Therapies directed at augmenting regulatory T cell (Treg) activities in vivo as a systemic treatment for autoimmune disorders and transplantation may be associated with significant off-target effects, including a generalized immunosuppression that may compromise beneficial immune responses to infections and cancer cells. Adoptive cellular therapies using purified expanded Tregs represents an attractive alternative to systemic treatments, with results from animal studies noting increased therapeutic potency of antigen-specific Tregs over polyclonal populations. However, current methodologies are limited in terms of the capacity to isolate and expand a sufficient quantity of endogenous antigen-specific Tregs for therapeutic intervention. Moreover, FOXP3+ Tregs fall largely within the CD4+ T cell subset and are thus routinely MHC class II-specific, whereas class I-specific Tregs may function optimally in vivo by facilitating direct tissue recognition. To overcome these limitations, we have developed a novel means for generating large numbers of antigen-specific Tregs involving lentiviral T cell receptor (TCR) gene transfer into in vitro expanded polyclonal natural Treg populations. Tregs redirected with a high-avidity class I-specific TCR were capable of recognizing the melanoma antigen tyrosinase in the context of HLA-A*0201 and could be further enriched during the expansion process by antigen-specific reactivation with peptide loaded artificial antigen presenting cells. These in vitro expanded Tregs continued to express FOXP3 and functional TCRs, and maintained the capacity to suppress conventional T cell responses directed against tyrosinase, as well as bystander T cell responses. Using this methodology in a model tumor system, murine Tregs designed to express the tyrosinase TCR effectively blocked antigen-specific effector T cell (Teff) activity as determined by tumor cell growth and luciferase reporter-based imaging. These results support the feasibility of class I-restricted TCR transfer as a promising strategy to redirect the functional properties of Tregs and provide for a more efficacious adoptive cell therapy.
    PLoS ONE 01/2010; 5(7):e11726. · 3.73 Impact Factor
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    ABSTRACT: Hepatitis C Virus (HCV) is a major public health concern, with no effective vaccines currently available and 3% of the world's population being infected. Despite the existence of both B- and T-cell immunity in HCV-infected patients, chronic viral infection and HCV-related malignancies progress. Here we report the identification of a novel HCV TCR from an HLA-A2-restricted, HCV NS3:1073-1081-reactive CTL clone isolated from a patient with chronic HCV infection. We characterized this HCV TCR by expressing it in human T cells and analyzed the function of the resulting HCV TCR-transduced cells. Our results indicate that both the HCV TCR-transduced CD4(+) and CD8(+) T cells recognized the HCV NS3:1073-1081 peptide-loaded targets and HCV(+) hepatocellular carcinoma cells (HCC) in a polyfunctional manner with cytokine (IFN-gamma, IL-2, and TNF-alpha) production as well as cytotoxicity. Tumor cell recognition by HCV TCR transduced CD8(-) Jurkat cells and CD4(+) PBL-derived T cells indicated this TCR was CD8-independent, a property consistent with other high affinity TCRs. HCV TCR-transduced T cells may be promising for the treatment of patients with chronic HCV infections.
    PLoS Pathogens 01/2010; 6(7):e1001018. · 8.14 Impact Factor

Publication Stats

2k Citations
445.23 Total Impact Points

Institutions

  • 2011–2014
    • Loyola University Medical Center
      • Department of Pathology
      Maywood, Illinois, United States
  • 2006–2014
    • Loyola University Chicago
      • Oncology Institute
      Chicago, Illinois, United States
    • University of Illinois at Chicago
      Chicago, Illinois, United States
  • 1998–2010
    • Medical University of South Carolina
      • • Division of General Surgery
      • • Department of Surgery
      • • Hollings Cancer Center
      Charleston, SC, United States
  • 2003–2009
    • University of Chicago
      • Department of Surgery
      Chicago, IL, United States
    • Duke University Medical Center
      • Department of Surgery
      Durham, NC, United States
  • 2005–2006
    • The University of Chicago Medical Center
      • Department of Surgery
      Chicago, IL, United States
  • 1994–2000
    • National Cancer Institute (USA)
      • Surgery Branch
      Bethesda, MD, United States
    • California Institute of Technology
      • Division of Biology
      Pasadena, CA, United States
  • 1993–1999
    • National Institutes of Health
      • Branch of Surgery
      Bethesda, MD, United States