Lab Personnel

John W. Kappler, PhD,
Principal Investigator

Philippa Marrack, PhD,
Principal Investigator

Jo Alamri,
Admin. Assistant II

Kelly Bakke,
Admin. Assistant II

BakkeK@NJHealth.org

Dean Becker,
Research Specialist 2

Christopher Brown, Research Tech 1

Ella Kushnir,
Research Tech 3

Alana Montoya, Research Tech

Andrey Novikov, MD, PhD, Research Tech 1

Eric Treacy,
Research Tech

TreacyE@NJHealth.org

My research aims to address how the process of clonal dominance is programmed by the immune system.  Specifically, I focus on a family of molecules known as tumor necrosis family ligands, which helps to predict which cells will dominate the immune response following clearance of a pathogen.  By manipulating the expression of tumor necrosis family ligands, I aim to determine how to alter clonal dominance during the initial stages of infection, and furthermore how to induce proper clonal dominance in situations that have subverted elimination by the immune system such as established tumors.  Ultimately, these studies will further the understanding of how clonal dominance is programmed in the immune system and potentially identify novel targets for therapeutic intervention in cases of aberrant clonal dominance such as chronic infections and persistent tumors.

My research is focused on structural studies of proteins important in the immune system. I am currently working on the crystallization of a complex consisting of T Cell Receptor (TCR) and its partner, beryllium bound peptide-Major Histocompatibility Complex II (MHC II). This complex is known to activate an immune response to beryllium as part of the chronic lung disease berylliosis in susceptible individuals. Other crystallography goals includes crystallization of non-MHC TCR complexes.

I oversee the lab’s protein biochemistry core facility. I am the lab liaison for baculovirus-expressed proteins in insect cells, including MHC Class II’s, T Cell Receptors, MHC Class II Tetramers and T Cell Receptor multimers.

Auto-reactive CD4+ T cells are involved in autogenesis of Type 1 diabetes. In a nonobese diabetic mouse (NOD) model of type I diabetes, we have found  a neuropeptide WE14 as an antigen  for highly diabetigenic CD4+ T cell clones. WE14 is from posttranslational processing of Chromogranin A. My project is to identify WE-14 reactive CD4+ T cells in vivo, the time course of these cells appearing in pancreas and peripheral, and the T cell repertoire of We-14 reactive T cells. We will also study how Chromogranin A is processed in pancreas.

I am currently working on the co-crystallization of proteins with antibodies. Proteins are more prone to being crystalized with Fabs or Fvs that bind proteins. The antibodies are produced by hybridomas,and the Fab or Fv is harvested by enzyme digestion or expressed in E.coli or insect cells. In the regular fusion, the number of hybridomas that produce antibodies against the native form of protein is low. Therefore, I am also focusing on the enrichment of antigen specific B cells, especially the B cells that recognize the conformational epitopes of proteins.

I am interested in vaccines, adjuvants and memory T cell and antibody responses. The goal of my current project is to develop a contraceptive vaccine for cats and dogs as a low cost alternative to surgical sterilization. Our approach is to use viral vectors expressing reproductive proteins to break tolerance and induce immune responses that inactivate the reproductive system. Recombinant viruses are engineered through a combination of molecular biology and virology techniques. Vaccine efficacy is analyzed by immunology and endocrinology assays. We hope these vaccines will help alleviate cat and dog euthanasia in the U.S., as well as decrease rabies incidence in developing countries.

I work on determining the mechanism of immunogenicity of protein aggregates in the absence of adjuvant. I am currently using Influenza A virus nucleoprotein as a model protein and am studying immune responses mounted in mice vaccinated with denatured or otherwise aggregated nucleoprotein.

Nearly 25 years ago, scientists discovered that an oncogene named Bcl-2 protected cells from apoptosis (programmed cell death) making it the first known gene to promote tumors by preventing cell death rather than driving cell proliferation. Since that time numerous other Bcl-2 like family members have been described, some causing cell death, some preventing it. Even though these proteins have been extensively studied over the last quarter century, the precise mechanism for how they function is still unclear. I look at the native complexes these family members form before and after apoptosis in the hopes of gaining new insights into their function and regulation. 

My long-term research interest is in uncovering the role of genetic, molecular and cellular components in the development and progression of autoimmune diseases and the crosstalk between these components. My current work is focused on the phenomenon of general predisposition among females to many autoimmune diseases. During my work I identified a particular, previously unknown, population of B cells that was found at a much higher frequency in elderly wild type female mice than in young females, or in males of any age. Importantly, this B cell population was also found to be expanded in younger, autoimmune-prone mice and their appearance correlates with the onset of disease in these animals. Understanding the role of this new B cell population in onset and progression of autoimmune diseases is a focus of my current research in Dr. Philippa Marrack laboratory.

Recently our group has discovered a subset of B cells, called age-associated B cells (ABCs), which appear in elderly female mice and autoimmune prone mice of either gender. We and others have also found ABC-like cells in elderly women suffering from various autoimmune diseases. Our experiments suggest that these B cells can produce autoantibodies and contribute to these diseases. It has been shown that ABCs develop from follicular B cells and their appearance depends on TLR7 signaling. However, the factors involved in the development of ABCs are not known. In this study we explore the lineage defining transcription factors for ABCs. In particular the role of T-bet, a T box transcription factor, is investigated. ABCs express high levels of T-bet and ligation of TLR7 leads to up regulation of this transcription factor in B cells. These data make T-bet a good candidate for a lineage defining transcription factor for ABCs. To find out if this is so, we explored the role of T-bet in the differentiation of B cells. Our data demonstrate that T-bet is necessary and sufficient for the differentiation of B cells into ABCs which indicates that T-bet truly is a lineage transcription factor for these cells. Besides that we were able to identify other factors crucial for the generation of ABCs: interferon gamma (IFNg) and ligation of B cells receptor (BCR). Our results indicate that TLR7, BCR and IFNg signaling synergize in B cells driving high level of T-bet expression. Overall, these findings help to understand the role of T-bet expression in B cells and how changes in T-bet levels with age lead to the perturbations in B cell subsets leading to the age related onset of autoimmune disorders.

For as long as I’ve been alive, our lab has been interested in the T cell antigen receptor-peptide-major histocompatibility complex (TCR-pMHC) interaction.  Recently, we have shown that the evolution of this interaction is governed at least in part by germline-encoded amino acids in the TCR that can control thymic selection. My thesis project will highlight the rules that govern this interaction and address whether conserved solvent-exposed amino acids on the MHC can also control thymic selection. To accomplish this, we are using zinc-finger nuclease (ZFN) technology to create mutant MHC knock-in mice whose TCR repertoire can be extensively studied.

Major histocompatibility complex (MHC) molecules present peptides to T cell receptor (TCR) to enable T-lymphocytes to recognize epitopes and distinguish self and foreign antigens. The type 1 diabetes is a T cell mediated autoimmune disease associated with MHCII alleles.  My research is base on the recognition mechanism of TCR molecules to peptide bonding MHC-II in type1 diabetes. We use structural biology methods to investigate the process of peptide presentation, T cell receptor recognition and the regulation of this interaction.

I am currently studying the repertoire of murine αβ T cells and the bias of T cell receptors for reaction with MHC. 

I am working on the TCR recognition of MHC and peptide in three ordered levels combining the immunological and structure biological means. The first level is about the basic principal of how TCR is biased to recognize highly polymorphic MHC and infinite peptides. The second level is about the mechanism of TCR related disease. We are taking the metal contact dermatitis as one target. I would like to know what kinds of inappropriate, self-protein–derived peptide antigens combined with metal are recognized by TCR and how they are recognized under the basic principal of TCR/pMHC recognition leading to atopic Dermatitis. The third level is about how me can do to help defending certain diseases based on the basic principal of TCR/pMHC recognition and mechanism of TCR related diseases from the previous two levels. We manipulated the TCR recognition of tumor antigens to enhance the T cell activation and break the tolerance to help defending tumor. We would like to establish the novel effective ways based on updating findings and plant these ways to more other tumors or TCR related diseases.

Mucosal associated invariant T (MAIT) cells are a population of T cells that express a semi-invariant αβ T cell receptor and recognize an unknown ligand presented by the MHC class I-like molecule MR1.  Both the invariant portion of the MAIT TCR and MR1 have been extraordinarily conserved throughout the course of evolution. The degree of conservation of MAIT cells and the fact that they comprise a surprisingly large portion of the T cell repertoire suggests that they have an important role in the immune system.  My work focuses on how the MAIT TCR recognizes MR1 and characterization of the ligand presented by MR1.