Institute for Immunity, Transplantation and Infection

ITI Seed Grants 2012

 

The Stanford Institute for Immunity, Transplantation and Infection (ITI)

Announcing the Recipients of the 2012 ITI Seed Grants and Young Investigator Awards
funded by:

2012 ITI Seed Grant and Young Investigator Award Abstracts

Novel technologies to define the role of NK cells in immunity to HIV-1
Catherine Blish, Holden Maecker

Combatting viruses requires the coordinated efforts of innate and adaptive immune systems.  While adaptive antiviral responses traditionally receive the most attention, these responses alone may be too little and too late to prevent infections, particularly with viruses like HIV-1 and herpesviruses that rapidly establish a latent pool of infected cells.  On the other hand, innate natural killer (NK) cells are uniquely suited to contribute to both control and prevention of infection.  NK cells are “early responders”—cells that can immediately lyse infected cells without the need for prior sensitization.  Emerging evidence points to a potential role for NK cells in control and prevention of HIV-1 infection, and we hypothesize that specific subsets of NK cells play a critical role in the prevention and control of HIV-1 infection.  We therefore seek to tackle a high-risk high-reward project by pairing innovative new technologies with human studies of HIV-1 infection to identify the precise role of NK cells in combatting HIV-1.  To do this, we will build an interdisciplinary collaboration capitalizing on Dr. Blish’s experiences in translational HIV-1 research and Dr. Maecker’s expertise in emerging flow cytometry platforms.  Prior studies of human NK cells have been limited by the fact that no technology existed to allow comprehensive, simultaneous evaluation of phenotype and function, particularly because there are >20 natural killer receptors and current platforms of fluorescence flow cytometry are limited to 18 colors. To overcome these limitations, we will develop a 40-parameter single cell mass cytometry, or CyTOF, panel to comprehensively evaluate NK cell phenotype and function.  We will use this platform to evaluate the specific phenotypes and functions of NK cells that are associated with suppression of HIV-1 replication in vitro, and with resistance from HIV-1 acquisition in vivo.  Overall, we seek to identify new pathways to prevent and control HIV-1 infection by harnessing the power of NK cells. 

Influenza virus tropism for human nasal epithelial cells of the upper airway
Harry B. Greenberg, MD, Stanford University/VAPA Health Care System

Influenza virus is responsible for annual epidemics and intermittent pandemics resulting in significant human morbidity and mortality worldwide. A current licensed influenza vaccine consists of live attenuated influenza viruses administered via intranasal spray, which mimics the natural route of infection permitting viral replication in cells of the upper airway.  The human nasal cavity and sinuses contain different cell types with distinct cell markers and functions. However, the replication targets of influenza virus in the human upper airway are poorly understood. The goal of this study is to identify these target cells and their response to influenza infection by recovering cells from human nasal cavity and infecting them with influenza virus in the test tubes. Our findings from this pilot study will form the basis for future studies focusing on nasal immune responses to influenza infection and vaccination. 

Lymphomagenesis Induced in Response to Hepatitis C Virus Infection
Ron Levy, Shoshana Levy

Infectious agents play role in the development of several types of cancer. This project is aimed at examining the role of hepatitis C virus (HCV) in the induction of lymphomas, tumors of the immune system. We will test the hypothesis that antibody-producing cells (B lymphocytes) specifically aimed at eliminating the virus are actually the ones that the virus stimulates causing uncontrolled proliferation.

Examination of the functional interactions between Natural killer cells and their ligands
Sheri Krams, Carlos Esquivel, Manish Butte

Natural killer (NK) cells are important in the immune response against tumors and virally infected cells. Studies from our group and others have implicated NK cells in promoting both acute and chronic allograft injury. NK cells are abundant at the site of graft injury and produce proteins that result in tissue damage. However under certain circumstance NK cells can facilitate tolerance to an allograft. One of the goals of our studies is to understand this apparent paradox and utilize this information to induce tolerance to a solid organ allograft. Our new results suggest that NK cells can activate and regulate other cells of the immune system and that this crosstalk has important implications for both allograft rejection and the induction of tolerance after transplantation. We have identified receptors on NK cells that are important for NK cell activation by dendritic cells and tumor cells respectively. We propose to utilize state of the art microscopy techniques to visualize the interactions of NK cells with cellular targets in the NK cell immunological synapse, a specialized area of communication between cells. Understanding how NK cells interact with tumors, pancreatic  cells, and cells of the immune system will have wide-reaching implications in the treatment of cancer, type 1 diabetes, and in inducing tolerance to solid organ allografts.

T-cell Mediated Responses to H1N1 Vaccination and Narcolepsy
Emmanuel Mignot, Elizabeth Mellins

Narcolepsy-cataplexy, a disabling and lifelong sleep disorder, is caused by loss of ~70,000 hypocretin (hcrt) producing neurons in the hypothalamus.  Narcolepsy is extremely tightly associated with DQ0602 (~99% versus 25%), suggesting antigen presentation by this allele is crucial to disease development.  In addition, we found a strong association with the F allele of the J24 segment of the TCRA locus. Recent data strongly suggest that pandemic H1N1 influenza A infection or vaccine may precipitate the onset of narcolepsy.  Strikingly, in Sweden and Finland, the 2009-2010 vaccination using an adjuvanted pH1N1 vaccine (Pandemrix, GSK) was associated with a increase in the incidence of narcolepsy in DQ0602 children.  We now suggest that narcolepsy development is promoted by (i) a specific immune–mimicry component, mediated through the presentation by DQ0602 of an epitope contained in pH1N1 and other flu strains to a specific TCR idiotype, and (ii) non-DQ0602-related contributors, such as adjuvants, fever, streptococcal infections or superantigens.  With the aim of characterizing T cells that may drive the development of narcolepsy in DQ0602 individuals, the goal of this pilot proposal is to identify DQ0602-binding epitopes in H1, N1 and hypocretinWe will screen overlapping peptides from H1, N1, PB1 (also differed in the vaccine) and hypocretin for binding to DQ0602. Identified peptides will be used to isolate and characterize reactive T cells by tetramer staining and functional assays.  We also will test the prediction that these T cells disproportionately utilize the J24 segment (generally in <1% of the TCR repertoire), and the J24/F allele in particular, in individuals with narcolepsy.  We will look for cross-reactive DQ0602-restricted H1N1 and hypocretin peptide-specific CD4 T cells and, if found, we will characterize such T cells in narcoleptic and non-affected (DQ0602) individuals.  Our long-term goal is to elucidate the pathogenesis of narcolepsy in affected DQ0602 vaccine recipients.

Comprehensive Survey of Twins for Immunologicall-based Diseases
Kari Nadeau, MD, PhD, Stanford University School of Medicine, Division of Immunology and Allergy, Gary E. Swan, PhD, SRI International, Center for Health Sciences

The field of immunology is in a state of rapid discovery with the advent of increased understanding of the extent to which human immunological processes and mechanisms underlie common and rare conditions. Because the discovery of immunological markers of disease in humans is still in the early stages, the extent to which many of these markers are influenced by genetic and/or environmental sources of variation remains to be determined. The use of the twin design (identical and fraternal twins) is a cost-effective way to determine the relative proportion of genetic and environmental influence both on the occurrence of conditions of known or suspected immunologic etiology as well as on biomarkers that are either associated with or predictive of these conditions. For this project, we propose to conduct a comprehensive survey of the 3,100 twins in the Twin Research Registry at SRI International for a number of known or suspected autoimmune diseases as listed in the Institute of Transplantation and Immunology (ITI) Interdisciplinary Research Award announcement (e.g., chronic fatigue syndrome, sarcoidosis, transplant tolerance, allergies, infectious diseases, autoimmunity, aging) and, more specifically, those provided by ITI investigators following an informal survey (e.g., celiac disease, inflammatory bowel disease, cytomegalovirus, Epstein-Barr virus, Hepatitis B and C, cardiovascular disease, and primary antibody immunodeficiency). By doing a more comprehensive survey of the twins, we will develop a repository of data to address ITI investigators’ questions about the prevalence of various conditions of interest as they arise. Doing so will not only be time- and cost-efficient, but it will provide a database upon which several of the ITI investigators could rely to further their research aims. To our knowledge, this would be the first immunologically-focused survey of twins to be conducted and, in itself, would represent a unique resource. Successful completion of the scope of work could provide an important first step toward building a national twin registry that would be fine-tuned to provide important data at other centers of the CCHI network. A larger scale, immunologically-focused registry will be required to fully utilize the twin design for rare conditions.

YOUNG INVESTIGATORS

Epigenetic control of T cell fate: miRNA expression in ageing, infection and vaccination
Mary Cavanagh

 Almost all cells in our bodies carry a full copy of our genome. However, each cell only expresses a fraction of the total genes available. Control of gene expression can come from molecules outside the genome and this is referred to as epigenetic control. The production of short sequences of nucleic acids called microRNAs (miRNAs) provides epigenetic control, and may direct the expansion and contraction of immune cells during and following infection.

T cells undergo massive proliferation in order to fight an invading pathogen. Once infection is cleared, most of these T cells are no longer needed and die. However, a small proportion survive to provide protection against future disease. As we age, this population of memory T cells expands, but does so unevenly. T cells specific for the virus CMV divide, eventually dominating the memory pool. However T cells specific for other, similar viruses do not. For example, cells specific for VZV gradually decline, eventually allowing this virus to reactivate and cause disease (shingles). This project will use cutting-edge techniques to explore the differences in miRNA expression between different virus-specific T cells to see if any miRNAs could be targeted to maintain T cell populations during ageing or to boost numbers following vaccination.

Immune Correlates of Bone Loss in HIV
Philip Grant

Antiretroviral therapy has led to the dramatic improvement in the health of HIV-infected individuals. However, even with treatment, HIV-infected individuals still have increased rates of many age-associated illnesses including the thinning of bones (osteoporosis) and broken bones. The bone loss that occurs with the initiation of antiretroviral therapy in HIV-infected individuals appears to be at least partly driven by the immune system. Using stored blood from a clinical study, we will evaluate how varying levels of inflammation within the blood affect the rate of bone loss once antiretroviral therapy is started. We hope that with an improved understanding of bone loss, targeted treatment or screening could be used for those at highest risk for bone loss.

Immunomodulatory Therapy in Atherosclerosis – Inhibiting Plaque Inflammation
Ann Jagger

Heart disease remains the leading cause of death in the western world, responsible for nearly 2300 daily deaths in the US alone. Novel therapies to stem atherosclerosis, the process underlying cardiovascular disease, are urgently needed. This project focuses on the development of immunological-based therapies for atherosclerosis. Although our immune system is ordinarily concerned with protecting us against viruses and bacteria, immune cells can misdirect their damaging capacity against our own bodies, as it is the case in atherosclerosis. We propose to “re-educate” the cell responsible for promoting inflammation in the atherosclerotic plaque (known as dendritic cell) in such a way that the immune system stops its engagement in harmful inflammation and instead supports the healing process. We will explore how to redirect the function of dendritic cells in the laboratory and in the patient. This approach offers the potential of a more physiological treatment, as it would use the body’s own cells to restore balance, and avoid side effects related to drug use and suppression of the body’s protective immune responses. Most importantly, our approach is not unrealistic, as studies have already shown that “designer” immune cells have a clinical benefit to patients in a variety of cancers. We would like to build on current knowledge and bring cutting-edge therapeutic approaches to the field of atherosclerosis.

Synthetic Biology for Biosynthesis of Novel Antibiotics
Maureen Hillenmeyer

New antibiotics are urgently needed.  In particular, new classes of antibiotics are needed, with novel mechanisms of action that can target even the most drug-resistant bacteria.  Most antibiotics originate from natural products, which are secondary metabolites biosynthesized by enzymes in natural organisms.  However, research on natural products has stalled due to difficulties in extracting these compounds from natural sources, and difficulties in their chemical synthesis.  An emerging alternative is to express natural product biosynthetic pathways in the laboratory, in microbial cell factories such as E. coli and yeast.  This can ease engineering and increase yields of the drug.  We are developing methods in synthetic biology for rapid prototyping of novel enzymatic pathways encoding novel antibiotics.  We will couple these methods with directed evolution and high-throughput screening for antibiotic activity, in order to engineer natural products exhibiting novel mechanisms targeting drug-resistant bacteria.

Plasmacytoid Dendritic Cells and their Role in Transplant Tolerance
Audrey Lau

Liver allografts are well tolerated, and other solid organ allografts, such as the small intestine and kidney, transplanted concurrently with livers show improved graft outcomes.  However, the mechanisms underlying “hepatic tolerance” have yet to be elucidated.  It has been hypothesized that immature plasmacytoid dendritic cells (pDC) are inherently tolerogenic.  This work proposes to investigate properties of hepatic and small intestine pDC to elucidate a mechanism by which pDC induce tolerance, whether by T cell apoptosis and/or the generation of T regulatory cells.  We will further examine how small intestinal transplantation alone alters immune regulatory properties.  Finally, we will utilize hepatic pDC as cellular therapy in a novel murine model of small intestine transplant to induce antigen specific tolerance.  

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