School of Public Health and Health Sciences
Health Informatics And Implementation Science
Biostatistics And Health Services Research
Cutler Chair in Vascular and Endovascular Surgery
Melvin S. and Sandra L. Cutler Chair in Biomedical Research
An entry level postdoctoral position is open immediately in the laboratory of Dr. Susan L. Swain to study the factors that control the development and survival of CD4 and CD8 T cell memory. Graduate student experience with tissue culture, in vitro assay, flow cytometry, experience in mouse models on infectious disease and a knowledge of cellular and molecular immunology are all strongly desired.
<p >Rotations: Projects in the following areas <p >CD4 T cell memory. We can generate in vitro CD4 T cells that are for all extents and purposes identical to the memory CD4 T cells observed in vivo. In situ memory CD4 T cells persist at very low frequency and in most instances it is difficult to analyze them thoroughly using tetramer or multimer reagents both because of their low frequency and the relatively low specific affinity of the Class II reagents for the TcR. Being able to generate “recent” memory cells in vitro gives us the opportunity to analyze in detail the mechanisms by which memory CD4 T cells may contribute to secondary immunity and immune protection. Once identified. will determine if particular pathways are relevant in situ. We have discovered that memory CD4 T cells are superior in protection to those from the primary response and that they display pleitropic functions that have not been previously identified. <p > Cytotoxic CD4 Effectors. One unexpected function of CD4 T cells we identified is robust, perforin-dependent cytotoxic activity (7, 16). Cytotoxic activity by CD4 T cells has been reported in response to several infections, but its significance has not heretofore been established. We find that “Th1 polarized” CD4 effectors and more relevantly the CD4 effectors found in the lung following influenza infection, are able to kill infected or peptide-pulsed Class II-bearing targets and we find that this perforin dependent activity can work together with antibody to provide protection against lethal influenza challenge in otherwise unprimed mice (17). We also will determine when memory CD4 T cells re-express cytotoxic activity following in vivo challenge and how cytotoxic killing contributes to the memory cell mediated protection. We want to analyze how the program of cytotoxicity is induced in these “ThCTL”. <p > Memory CD4 Cells Enhance an Innate Response. Memory cells can act by becoming secondary effectors but they are best characterized by their ability respond rapidly even to low antigen doses, by producing cytokines and chemokines and it is assumed that these initial abilities are key to memory cell activity. However this assumption has not been directly demonstrated and the mechanisms involved and how they might contribute to immunity have not been elucidated. We find that restimulation of memory CD4 T cells leads to a markedly enhanced early innate response to influenza infection both in the lung and systemically (17). This response peaks 2-3 days after infection and is transient. We see enhanced production of IL-6 locally and systemically and enhanced production a broad spectrum of innate inflammatory mediators in the lung. We hope to determine in detail the pathways leading to optimum memory T cell-induced innate responses. We suggest a concurrent activation of CD4 memory cells may be an effective adjuvant for vaccination and will be testing this hypothesis as well as mechanisms that lead to viral control over the next couple of years. <p >Aging and Immunity: The study of the impact of aging on CD4 T cell function at the naïve and memory stages has lead us to better understanding of fundamental aspects of T cell behavior in addition to providing important information about what vaccine approaches are most likely to be successful for the aged. Nature of CD4 Aging “Defects”. We have identified multiple levels at which aged naïve CD4 T cells are defective including initial early response to TcR triggering, IL-2 production, expansion and effector generation. The defects in helper function and in the 20 response of memory cells generated from aged naïve CD4 T cells are particularly dramatic. In recent studies we have recapitulated memory age-associated defects in recently generated memory cells in vitro (23). In vitro aged memory cells are markedly defective in production of particular cytokines, IL-4, IL-5 and IL-2, while others are little affected (IFNg, IL-10, TNF), suggesting the aging “defect” may be restricted to loss of potential to make certain CD4 T cell subsets, such as those responsible for help to B cells .We will pursue this hypothesis both in vitro and in vivo. <p >We have found that aged naïve CD4 T cells are in fact longer-lived than their naïve counterparts (23). We find that reduced expression of Bim, a proapoptotic protein, is responsible for this increase in lifespan and that the increase in lifespan is required for the development of aging defects. We are now investigating the factors that regulate Bim expression. <p >Enhancement by Inflammatory Cytokines. We have shown that the defective effector generation responses of naïve CD4 T cells from aged animals can be overcome by IL-2 and by proinflammatory cytokines, in particular a mix of IL-1, IL-6 and TNF (20,21). We want to determine the extent to which the inflammatory cytokines can reverse the heritable aging defects and restore functional memory generation. We have developed in vitro models to test the generation of effectors and memory. In these models we are evaluating TLR agonists for their ability to restore aged naïve CD4 responses to peptide-pulsed derived dendritic cells (DC). Pre-incubation of DC with many TLR agonists, enhances expansion of the responding aged naïve CD4 T cells via a mechanism dependent on IL-6 that acts in part by increasing survival of the developing effector population. We plan to use this model to identify the extent of the rescue and what pathways and mechanisms contribute with the ultimate goal of evaluating whether specific TLR stimulation or stimulation of specific pathways might improve the response of the elderly to vaccines. We want to see if we can reproduce this model with human naïve CD4 T cells and DC derived from peripheral blood and if TLR agonists can also enhance those responses. <p >
David J. Freelander Memorial Professor in AIDS Research
Dr. Henninger is a vascular neurologist with research interest in the neurobiology of axonal injury associated with traumatic brain injury and its contribution to functional outcome.
LAB ROTATION PROJECTS AVAILABLE -- PLEASE CONTACT SAM BEHAR FOR MORE INFORMATION
Focus: We seek to understand how the causative agent of tuberculosis, namely the bacterium Mycobacterium tuberculosis evades host immunity, and how different components of the immune response work together to contain infection. Our ultimate goal is to inform vaccine development and the design of host directed therapy.
Rotation projects are available related to microbiota-gut brain axis and antibiotic usage and the sequelae of antibiotic use in hospitalized patients which include Clostridium difficile and multi-drug resistant organism infection and colonization.
Arthur F. and Helen P. Koskinas Professor in Biochemistry and Molecular Biotechnology
Imoigele P. Aisiku, MD’97 Chair in Health Equity and Diversity
UMass Memorial Health Care Chair in Biomedical Research
Potential Rotation Projects: Contact Dr. Luzuriaga for project details.
Barbara Helen Smith Chair in Preventive & Behavioral Medicine
Rotation Projects <p >We have identified a number of bacterial pathways that are required for bacterial viability or virulence. We are particularly interested in: Phosphosignaling systems that regulate cell wall synthesis Metabolic regulatory mechanisms that trigger the “dormancy” response observed during infection. <p >A variety of genetic, biochemical, and informatic methods will be used to define the functions of these genes and the role played by each during infection. <p >
Joseph M. Streeter and Mary Streeter DeFeudis Chair in Surgery
Richard M. Haidack Professor in Medicine
Dr. John Meyers Professor in Primary Care Medicine
Population and Quantitative Health Sciences
Biochemistry and Molecular Biotechnology
UMass Worcester Prevention Research Center
Prevention Research Center at UMass Chan
Healthcare Delivery and Population Sciences at UMass Chan - Baystate
Jack M. Wilson Chair in Biomedical Research
Joseph D. Early Chair in Biomedical Research