The NIH Autoimmunity Centers of Excellence
The Autoimmunity Centers of Excellence (ACE) is a cooperative research program sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), and the National Institute of Health (NIH) Office of Research on Women's Health. Columbia was chosen as one of the original four original ACE centers established in 1999 with Dr. Leonard Chess as Director. Currently there are nine ACE centers located across the United States. The nine current ACEs include in addition to the Columbia ACE other centers at the Brigham and Women's Hospital (Boston, MA); the Children's Hospital of Pittsburgh (PA); the Feinstein Institute for Medical Research (Manhasset, NY); Duke University (Durham, NC); the University of Alabama at Birmingham; the University of California at San Francisco; the University of Colorado (Denver, CO); and the University of Rochester (Rochester, NY). The main goal of this group is to execute a multi-disciplinary program of basic, preclinical and clinical research that focuses on tolerance induction and immune modulation to treat and prevent autoimmune diseases. In addition to basic laboratory research the centers are provided with the resources to conduct clinical trials and mechanistic studies on various autoimmune and immunologic diseases.

Overall Objectives of the Columbia ACE Program
The overall aim of Autoimmunity Centers of Excellence at Columbia is to establish an interdisciplinary basic and clinical research program at the college of Physicians and Surgeons and the Columbia Presbyterian Medical Center primarily focused on the evaluation of novel therapeutic approaches to five autoimmune diseases; rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), type one diabetes mellitus (T1DM) and scleroderma. In each of these diseases there are ongoing basic and clinical research programs involving pathophysiologic and/or clinical immunotherapeutic studies. We hypothesize that there are four principal events involved in the immunopathogenesis of these diseases: (1) predisposing genes establish a T-cell repertoire capable of recognizing self peptides intrinsic to the autoimmune process; (2) previously tolerant autoreactive CD4+ T-cell clones become activated and expand to change the T cell repertoire to reflect autoreactive effector T cells; (3) regulatory mechanisms, including the activation of TH1 and TH2 CD4+ T cell subsets as well as those involving CD8 T-cells fail, through processes such as clonal deletion or changes in the cytokine milieu and (4) pathogenic autoantibodies develop through cognitive T-cell B-cell interactions which effect tissue injury. The immunology program at Columbia has pioneered in the identification and study of biologically and clinically important molecules on the surface of human T lymphocytes. An important characteristic of the Columbia program has been its ability to bring basic discoveries made at the bench to the development of drugs employed in the treatment of human immune disease. which is illustrated here.

In these diseases one would predict that reducing the clonal expansion of relevant autoreactive T cells by blockade of T cell receptor signaling or interruption of the CD40 ligand-dependent pathway could down-modulate disease activity. Moreover, interruption of the inflammatory effector functions of T cells mediated by TNF or CD40L would similarly reduce disease potential. We propose to test these hypotheses in the above patients during the natural history of disease and during specific immune intervention. In particular, we will study patients with SLE treated with anti-CD40L; MS patients receiving IFN-β or anti-CD40L; T1DM patients receiving anti-CD3 and RA patients receiving the recombinant TNF receptor inhibitor (Embrel). In addition, a major focus of our ACE is in studying regulatory mechanisms employed by the immune system to effect self-nonself discrimination and down-regulate the auto-reactive T cell repertoire responisble for autoimmunity. In this area we are particularly interested in the role of CD4 and CD8 regulatory T cells in the control of autoimmune disease activity.

Key Personnel in the ACE Research Programs at Columbia include:
Leonard Chess, MD
Hong Jiang, MD/PhD
Robert Winchester, MD
Stephen Canfield, MD/PhD

In addition, the clinical research activities also involve the direct collaboration with Dr. Robin Goland, the Clinical Director of the Naomi Berrie Diabetes Center as well as Dr. Gerald Appel in the Division of Nephrology who is principally involved in ACE studies of autoimmune manifestations of renal diseacse including Lupus Nephritis.

Basic Scientific Research Themes in the Columbia ACE:
Research Theme 1- the analysis of antigen specific T cell clones in initiating the autoimmune process:
(a) Common to all autoimmune diseases is the idea that a very proximal event in the induction of autoimmunity is the initial cognitive encounter between a potentially autoreactive T cell with an antigen presenting cell expressing MHC/autoantigen-peptide complexes capable of functionally inducing the autoreactive T cell clones. These T cell clones effect autoimmune disease employing effector mechanisms that normally are used to combat infectious agents or tumor cells. These autoreactive clones are distinguished by the TCRs they express and this very basic consideration leads to the inescapable notion that the ultimate diagnostic signature for the presence of autoreactive T cells must be engraved in the TCRs expressed by autoreactive clones. Thus, a direct means of studying the clinical course of autoimmune disease will be the analysis of the TCR repertoire and the CDR3 regions of the TCRs expressed by autoreactive T cells. We directly test this idea by assaying T cell clones by TCR spectratyping before and after triggering by putative candidate autoantigens. In addition the overall antigen induced avidity of autoreactive clones are studied at a functional level. The study of avidity is of particular interest in the Columbia ACE because of recent evidence that immunoregulation is biologically targeted to the avidity of T cell clones. The analysis of the TCR spectrotyping and avidity is then studied in patients longitudinally during the natural history of disease and in some projects during immunologically based therapy (including anti-CD3 blocking antibodies, anti-CD40L, CTLA-4).

Research Theme 2- the role of the CD40L/CD40 pathway in the induction and control of autoimmunity
(a) Interruption of the CD40L/CD40 pathway can ameliorate autoimmune disease in numerous experimental animal models, including models of SLE, MS and inflammatory arthritis. Preliminary clinical trials in patients with systemic lupus erythematosus showed that the antibodies to CD40L produced in our laboratories as associated with decreased titers of anti-DNA antibodies. The mechanisms of this effect are under intense study in our ACE.
(b) It is unknown whether the primarily effects of anti-CD40L therapy in vivo are directed at the initial cognitive events of antigen specific T cell activation (T cell-APC interaction) with the induction of non-responsive or tolerant T cells or alternatively whether the effects will be at the more distal effector mechanisms of the immune response. The potential role of CD40L blockade in the induction of regulatory CD8 T cells is actively being studied.

(c) The effector mechanisms include T cell induction of B cell growth, differentiation and Ig class switching which may be of critical importance in diseases primarily mediated by IgG autoantibodies and /or immune complex formation. The effector mechanisms may also include interaction of T cells with macrophages, dendritic cells, fibroblasts, endothelial cells, platelets and other mesenchymal pathways.


Research Theme 3- approaches to the identification of the autoantigens that trigger the autoimmune process
(a) Our strategy will be to first to identify clinical situations where we will be more likely to find an expansion of relevant autoreactive T cells clones. These clinical situations will include the early stages of the dermal vasculitis in SLE, the joint fluid or synovial tissue from patients with new onset inflammatory arthritis, or the CNS from patients with new onset or recent relapses of multiple sclerosis.

(b) We will isolate putatively relevant T cell clones from the site of autoimmune inflammation by first isolating activated T cells (ie; cells CD25, CD69 or CD40L) and immortalizing these cells using HVS to establish libraries of autoimmune T cells. Activated T cells from these sites will be preferentially immortalized by HVS and libraries of immortalized T cells should be enriched in autoreactive cells.

(c) These immortalized T cell libraries will then be assayed with a panel of autoantigens for TCR activation or lymphokine and chemokine release. In addition, autoreactive clones will be assayed by TCRVB spectratyping and for avidity by ED50 analysis.

Theme 4- the analysis of regulatory mechanisms that control the outgrowth of autoimmune CD4+ T cells
(a) There is clear evidence that the primary initiating event in SLE, RA, MS, diabetes and scleroderma is the initial outgrowth of autoreactive CD4+ T cell clones. Thus, the cellular and molecular mechanisms, which control this outgrowth, are of pivotal importance.
(b) These include studies of the cytokines, which regulate the differentiation into TH1 and TH2 subsets, and the role of cognate interactions mediated by regulatory CD4+ T cells (Tregs) which regulate immune responses by the elaboration of cytokines like IL-10 and TGFb as well as cognate membrane interactions that have not been precisely elucidated as yet. The CD4 Tregs, however, are not directly involved in self-nonself discrimination and are known to suppress responses to both self and foreign antigens.

(c) In contrast, the research at Columbia by Dr. Hong Jiang has centered around studies of a subset of regulatory CD8+ T cells that have receptors that allow them to selectively suppress the autoreactive repertoire and at the same time facilitate the response to foreign antigens CD8+ T cells that have the capacity to selectively down-regulate autoreactive clone without down regulating the immune response to foreign pathogens. In this regard, Dr. Jiang initially identified a population of Qa-1 restricted CD8+ T cells, which mediate the resistance of autoimmune Experimental Allergic Encephalomyelitis (EAE) induced by the first episode of the disease. More severe symptoms of EAE develop, in a much less controllable fashion, during the relapse in CD8 knock out mice or the re-induction of EAE in Qa-1 knock out mice, indicating that Qa-1 restricted CD8+ T cells play an important role in maintaining peripheral self-tolerance.

During the past several years, Dr. Jiang together with Dr. Chess have further proposed and tested an “Avidity Model of Peripheral T Cell Regulation” in which self non-self discrimination can be achieved in the periphery by the Qa-1 restricted CD8+ T cells to selectively down-regulate intermediate avidity T cells to both self and foreign antigens. Because the peripheral self-reactive T cell repertoire is devoid of high avidity T cells compared with foreign-reactive repertoire due to thymic negative selection, the selective down-regulation of intermediate but not high avidity T cells enables the immune system to suppress autoimmunity without damaging the on going immune response to foreign pathogens, a functional status of self non-self discrimination.

Recently, these studies further revealed that a heat shock peptide (Hsp60sp), coupled with the MHC class Ib molecule Qa-1, is a surrogate target structure, preferentially expressed at a higher level on the intermediate avidity T cells and specifically recognized by the Qa-1 restricted CD8+ T cells. Thus, perceiving the avidity of T cell activation can be translated into peripheral T cell regulation to discriminate self from non-self by a simple and unified mechanism of selective down-regulation of intermediate avidity T cells. The biological significance of this concept was demonstrated by the evidence that regulatory CD8+ T cells, specifically induced by and down-regulate Qa-1/Hsp60sp expressing cells, cross-protected animals from either autoimmune Experimental Allergic Encephalomyelitis or Type 1 Diabetes without damaging the ongoing immune response to foreign antigens. “Cross-protection” occurs because potentially pathogenic self-reactive T cells included in the pool of intermediate avidity T cells are capable of preferentially expressing common surrogate target structures on their surface to be subject to the down-regulation by the Qa-1 restricted CD8+ T cells, regardless of which antigens the target T cells are triggered by. The studies thus suggested that the immune system discriminates self from non-self, during adaptive immunity, not by recognizing the structural differences between self versus foreign antigens, but by perceiving the avidity of T cell activation.

These studies present evidence for a nascent paradigm-shifting scientific theory in the field of immune regulation. If proven correct, the conceptual framework of the “Avidity Model” may open a new era of modern immunology and profoundly change the way that we deal with immunologically relevant clinical problems in general. For example, identification of the regulatory mechanisms, that function to discriminate self from non-self, would lead to new possibilities of novel clinical interventions to prevent and treat autoimmune diseases without damaging the normal on going anti-infection and anti-tumor immunity, which is the major side-affect of the currently used immuno-therapeutic drugs. In addition, the specificity of the regulation is not at the level of the antigens that activate the target T cells, control of auto-immune diseases could thus be achieved independent of the knowledge of the particular self-antigens involved, in any given auto-immune disease, that are largely undetermined at the present time. Particularly, manipulation of the common target structures recognized by Qa-1 restricted CD8+ T cells is the basis for potential therapeutic interventions to specifically enhance or block this regulatory pathway in vivo. In this regard, the potential application of such interventions in man is based on the evidence that the human homologue of Qa-1, HLA-E, can function as a restricting element for human regulatory CD8+ T cells. The studies in humans are being actively explored in the ACE center in the analysis of immunoregulation in type 1 diabetes and in multiple sclerosis.

Theme 5- deciphering the transcribed genetic phenotypic signatures that reflect the autoimmune process directly from the analysis of human tissue.
In addition another important aspect of the clinical research program is the goal of application and development of the latest immunologic, cell biologic and genetic approaches directly to human tissues. In this regard, Dr. Winchester’s lab is directly studying renal tissue from patients with lupus nephritis and is constructing and deciphering a transcriptional phenotype of isolated glomeruli by determining the gene expression pattern in each of the main compartments of the kidney involved by lupus nephritis. Thus glomeruli, tubules, and the periglomerular and intertubular interstitium are being individually analyzed by laser capture technology, RNA amplification technologies, and the optimization of the microarray platforms. Interestingly, during the past grant period, Dr. Winchester applied these technologies to other vascular disorders including calcific aortic stenosis, traditionally viewed as a degenerative process but has been found to have a major inflammatory component which will now be pursued in the ACE.

Autoimmunity Center at Columbia: Basic Science and Translational Projects:
Project #1: The role of the CD40L/CD40 pathway in the Immunopathogenesis of SLE and the control of the autoimmune repertoire with particular attention to discerning the mechanism of long term tolerance induced by antibody blockade with anti-CD40L antibody in both mouse and man. P.I. Leonard Chess

Project #2: Immunoregulatory mechanisms controlling the TCR repertoire in murine (EAE) and human T1D and multiple sclerosis with particular attention of the relationship treatment effects with respect to the avidity model of immunoregulation. P.I. Hong Jiang

Project # 3: Antigen and non-antigen driven TCR repertoires in inflammatory arthritis/TNF blockade/chemokine blockade. In addition, Dr. Winchester is studying inflammatory cells present during the natural history of aortic stenosis with respect to native and adoptive immune functions and T cell repertoires P.I. Robert Winchester

Project #4: Control of T cell activation and the autoreactive TCR repertoire in Human Type I diabetes mellitus during the natural history of disease and with therapy. The studies here will emphasize the analysis of the self-nonself discrimination to immunoregulatory mechanisms. P.I. Stephen Canfield, Len Chess and Hong Jiang