www.cwru-id.org

Dr. Armitage is the Vice Chair for Education of the Department of Medicine and Director of University Hospitals Internal Medicine Residency Program. His interests are in clinical infectious diseases (pneumonia, osteomyelitis, prosthetic infections, infections in the elderly, endocarditis), travel medicine and medical education.

Heterogeneity of human immunodeficiency virus type 1 (HIV- 1) has a significant impact on viral fitness, disease progression in the patient, emergence of drug resistance, and development of an effective vaccine. Although encompassing a broad range of topics, all of our research projects are related to HIV- 1 genetic diversity.

1. Treatment with antiretrovirals results in the emergence of drug resistant HIV- 1 isolates. In many instances, these drug resistant isolates may pre-exist and even predominate in the intrapatient HIV population prior to treatment. We are studying the baseline and emergence of drug resistant HIV- 1 isolates in HIV-infected Ugandans. Several divergent HIV subtypes co-circulate in Uganda which (i), are divergent to HIV- 1 strains in North America and Europe and (ii), may be less susceptible to antiretrovirals.

2. As part of a program project, we are testing the anti-HIV activity of beta chemokine analogs. This screen involves testing these drugs against a panel of 15-20 divergent, primary HIV- 1 strains, isolated throughout the world. A beta chemokine analog may be employed as vaginal viricide to prevent HIV infections in developing countries.

3. Initiation of reverse transcription is a complex, specifies-specific process in the retroviridae family. Even though lentiviruses (HIV, feline immunodeficiency virus, equine infectious anemia virus) all use tRNALYS.3 for initiation of reverse transcription, each retrovirus has evolved to use different but specific initiation complexes. We have developed an reconstituted, in vitro assay to study initiation of reverse transcription in a variety of retroviruses.

Dr. Aung's research is to 1) study the role of plasminogen/plasmin proteolytic system for the release of biologically active TGF-b1 by mononuclear cells in response to Mycobacteria and mycobacterial products and 2) study the role of b-chemokines on HIV disease by characterizing the expression of chemokine receptors in the lung mononuclear cells of HIV-infected subjects and to determine the biological phenotype and co-receptor usage of their lung and blood viral isolates.

Bacterial resistance to beta-lactams is threatening the most potent antibiotics we have. The research interests in our laboratory involve understanding the structure function relationships of the class A beta-lactamase, SHV-1. This chromosomal and plasmid encoded beta-lactamase is usually found in Klebsiella pneumoniae. Variants of this enzyme (SHV-2, -5, -8, -12) confer high level resistance to third generation cephalosporins (cefotaxime and ceftazidime) and the monobactam, aztreonam. This resistance can render ineffective the most frequently used drugs to treat serious nosocomial infections. Our goals are to understand what amino acid substitutions permit evolution of novel substrate profiles and what factors control expression of these periplasmic enzymes. By using site directed mutagenesis and immunological tools to quantify expression, we are able to draw conclusions as to why these highly resistant variants may have arisen in nature. We are also interested in quantifying beta-lactamase expression in organisms harboring Class C beta-lactamases. We have developed antibodies able to detect the presence of this class of enzymes in clinical strains, thereby facilitating molecular epidemiological investigations.

Infections in the elderly are emerging as one of the most important issues in clinical infectious diseases. The elderly patient as a compromised host is often infected with bacteria highly resistant to antimicrobials. The excessive use of broad spectrum agents in the nursing home and in the community may be accelerating this process. Developing algorithms for appropriate treatment of these infections, assessing the factors that accelerate the development of resistance, and finding interventional strategies that can stem these processes are an urgent priority. Our clinical research interest is in assessing how frequently elderly patients are the colonized with multi-resistant Gram negative bacilli and how these pathogens disseminate in this population

Research Program Title: T cells and the immune response to infectious pathogens such as Mycobacteriurn tuberculosis and HIV T -cells play a critical role in the immune response to the intracellular pathogen M. tuberculosis, which is estimated to infect one third of the world's population. T cells regulate the acquired immune response which controls primary infection and provide protection against exogenous reinfection. CD4+ T cells traditionally have been considered the main T cell subset responsible for regulating protective immune responses to M. tuberculosis. However, in addition to the CD4+ T cell, both gamma-delta T cell receptor bearing T cells (gamma delta cells) and CD8+ T cells have a role in protective immunity to M. tuberculosis. The study of CD4+, CD8+ and gamma delta T cell responses to M. tuberculosis is the main interest of my laboratory. The focus is on characterization of mycobacterial antigens recognized by CD4+ and gamma-delta T cells, the role of cytokines such as IL-2, IL-12, IFN-gamma, K-l0 and TGF-beta in modulating the T cell responses to M. tuberculosis, the functional interaction of antigen-specific T cells with macrophages infected with mycobacteria, and the mechanisms used by M. tuberculosis infected macrophages to process and present antigens from the phagosome to the cell surface to these different T cell subsets. These studies use cellular immunological and cell biologic approaches to study the biology of M. tuberculosis infected macrophages and T cells. In addition, a murine in vivo model of M. tuberculosis infection of the lung is used to study the unique micro-environment where M. tuberculosis infection occurs and immune responses are initiated.

My research interests relates to T cell immunity to mycobacterial infection. I have focused recently on understanding the mechanisms which T cells employ to destroy infected cells and kill intracellular M. tuberculsosis. We have demonstrated that CD4+ and CD8+ T cells can kill intracellular MTB in monocytes. This does not appear to require perforin or FAS/FASL. Future studies are in progress to elucidate the mechanism for this growth restriction. These include studying the role of ATP and various cytokines. Other studies include an interest in antigen processing of mycobacteria by infected antigen presenting cells. We are currently in the process of generating immortal mycobacteria specific T cell lines using an HLA-A2 transgenic mouse which can used in the study of MHC class I antigen processing of mycobacteria in humans. Previously we have shown that MHC I antigen processing occurs by a vacuolar post endoplasmic reticulum process. Further exploration with better reagents is planned.

The goal of my research is to develop a better understanding of the mechanisms by which antibiotics promote intestinal colonization with vancomycin-resistant enterococci (VRE). A mouse model of VRE intestinal colonization and observational studies in colonized patients are utilized to evaluate the effect of antibiotics on VRE colonization. Anaerobic continuous flow cultures and ribosomal DNA techniques are being used to evaluate the interaction between VRE and the normal intestinal flora. The data derived from these studies will be used to guide selection of antibiotics that are less likely to promote the dissemination of VRE.

My research is conducted in collaboration with W. H. Boom. M.D whose primary interests focus on human T cell responses to Mycobacterium tuberculosis. Recently, we have set up a mouse model to study pulmonary immune responses and use M. bovis-BCG as the model organism (Fulton, S. A. et al. Am. J. Resp. Cell Mol. Biol. 22, pp. 333-334, 2000). The overall aim of our studies is to understand how innate and T cell mediated immune responses develop within the lung. Growth of M. bovis-BCG, cytokine expression, immune cell activation and histopathology are principal endpoints and involve basic bacteriologic, ELISA, RT-PCR, flow cytometric and histologic techniques.

My independent experimental interests focus on:

1. Modulation of pulmonary immune responses using alveolar deposition of cytokines and chemokines.

2. Mycobacteriocidal and immunomodulatory functions of alveolar neutrophils.

3. Immunologic functions of respiratory epithelial cells.

Many of these studies have potential application to studies of human lung cells.

Both human and murine studies will help characterize protective immune responses and assist in developing novel vaccines and immunotherapy for controlling M. tuberculosis infection.

Dr. Graham's interest is in clinical infectious diseases (endocarditis, pneumonia, bacterial infections) and medical education for the students, residents and fellows.

My interest lies in clinical research in therapies for HIV infection, and their complications. I participate in the AIDS Clinical Trials Unit, as well as pharmaceutical sponsored trials for HIV therapy. I am also involved in a multicenter cross-sectional study looking at the metabolic changes and fat redistribution seen in HIV patients on highly active retroviral therapy.

Dr Hirsch's research interest is the study of immune responses during human tuberculosis. One major aspect or her work has been devoted to studies of cytokine responses to M. tuberculosis and its components by T-cells both in the peripheral blood from healthy individuals and from patients with TB, most recently, in a longitudinal study evaluating in vitro cytokine production in patients with active pulmonary TB in Uganda. Additional work has focused on the on the role of immunosuppressive cytokines produced by mononuclear phagocytes from patients with newly diagnosed pulmonary tuberculosis in depressed. The focus of a second, and more recently developed area of research is the contribution of both T-cell and macrophage apoptosis to host immune reactivity in patients with active TB. A number of studies are currently ongoing, examining potential mediators and mechanisms of the apototic process, including molecules such as Fas, FasL and TNF-a as well as members of the Bcl-2 family both in PBMC from patients with pulmonary tuberculosis and in T-cells obtained by thoracocentesis from patients with pleural tuberculosis. The latter protocol also includes subjects dually infected with M. tuberculosis and HIV, and serves as a model to evaluate the effect of HIV disease to antituberculous host immune responses. Finally, as the component leader of applied immunology of the Tuberculosis Treatment and Prevention Unit, she has developed an interest in identifying and defining immunological markers of response to tuberculosis treatment, which then could be used as surrogates of antituberculous immunity during clinical trials.

My current research interests include pulmonary infections in immunosuppressed patients, clinical trials of new drugs and immunotherapeutic agents for the prevention and treatment of TB, regulation of humoral and cell-mediated host immune responses during tuberculosis treatment, and field trials of new diagnostics for tuberculosis for low-income countries, and HIV preventive vaccines. I am a consultant on a Wellcome Trust Funded clinical trial of the safety and efficacy of adjunctive methylprednisolone for the treatment of tuberculous pleurisy in HIV-infected adults in Uganda and an international multicenter trial of adjunctive interferon gamma immunotherapy for the treatment of drug resistant tuberculosis.

Dr. Lederman's research studies have concentrated on mechanisms of immune deficiency in HIV-1 infection and have utilized the clinical treatment trial as a means to explore questions of HIV-1 disease pathogenesis. He is presently the director of the AIDS Clinical Trials Unit at CWRU and the acting director of the CWRU Center for AIDS Research. Dr. Lederman studies CD4+ T cell function in HIV disease and has characterized the restoration and the limits of restoration of immune function in HIV disease after application of potent antiretroviral therapies.

Dr. Lerner's interest is in clinical infectious diseases (antibiotics and bacterial infections) and medical education.

Bacterial cells have the ability to communicate with each other by using small chemical signals. This process of cell-to-cell communication has been termed quorum sensing. We are studying quorum sensing in two organisms, Escherichia coli and Proteus mirabilis. In both systems, we are interested in addressing the following questions: (i) How do cells respond to the signals; (ii) What are the signals and (iii) What are the physiological roles of cell-to-cell signaling in each organism. My lab uses a combination of genetic and biochemical approaches to answer these questions.

My laboratory's primary interests are in the molecular genetics of antibiotic resistance in enterococci. Ongoing projects include analyses of large transferable genetic elements that encode resistance to vancomycin and investigation of the regulation of ampicillin resistance in Enterococcus faecium. We also have an ongoing interest in the analysis of extended-spectrum beta-lactamases in gram-negative bacilli.

Dr. Salata's research interests include international studies in HIV infection and sexually transmitted diseases, nosocomial infections, vaccine and non-vaccine strategies to impact on HIV seroincidence, infections in immunocompromised hosts, and the epidemiology of infectious diseases. These are collaborative with other faculty members involved in HIV and bacterial pathogens and requires close interactions with members of the Department of Epidemiology and Biostatistics.

The purpose of my current work is to contribute to the understanding of the human host immune response to the infection with M. tuberculosis. In pursuit of this aim, a large part of my work in the last years was carried out in tuberculosis endemic countries such as Mexico and Uganda. Because the entry portal for M. tuberculosis is the human lung we have studied pulmonary immune responses in comparison with systemic (blood) responses in patients during active tuberculosis, healthy household contacts of patients with tuberculosis and healthy controls from the community. Frequencies of antigen-specific cytokine-producing cells [(enzyme-linked immunospot assay (ELISPOT assay)], cytokine concentrations (ELISA), and DNA synthesis (3H-thymidine incorporation) were studied. Further we determined surface markers on lung and blood cells by flow cytometry (Facs-analysis). More recently I have started to focus my attention on the interaction of M. tuberculosis with interferon-g-induced cellular responses. Interferon-g is a key cytokine in the protective host immunity against M. tuberculosis. However, interferon-g appears insufficient to control the progress of M. tuberculosis-infection. Molecular techniques (TaqMan Real Time PCR and electromobility shift assays) are currently employed to unravel a probable role of M. tuberculosis in interfering with the mechanisms by which Interferon-g regulates specific genes. As side projects I am interested in the role of M. africanum in human tuberculosis in Uganda and in the potential of the ELISPOT assay as a diagnostic tool for the detection of infection with M. tuberculosis.

IFN- plays a critical role in mycobacterial infection. Mutation of IFN- or IL-12 receptor are associated with disseminated M. avium infection. IL-12 and IL-18 are potent IFN- inducers and as such are important for protective immunity against M. avium. Since infected monocytes express IL-12 and IL-18, T cell responses and IFN- expression are partially dependent upon the interaction with infected monocyte/macrophages. Activation of IL-18 is depedent on caspases. Virulent SmT strain induces less IL-1 , IL-12 and IL-18 expression and ICE activation, thereby limiting IFN- expression which would favor mycobacterial growth. SmD induces higher IL-1 , IL-12 and IL-18 expression and ICE activation which may contribute higher IFN- production and limiting intracellular M. avium growth. Additional determinants of M. avium pathogenicity may involve monocyte apoptosis. Caspases and mitogen-activated protein kinases (MAPK) (ERK, p38 and JUK) may play key mechanistic roles in apoptosis which modulat s host defenses against mycobacteria. Differential induction of monokines, caspase and MAPK activation by different colony morphotypes may elicit unique patterns of cell activation and apoptosis which could subsequently modulate intracellular M. avium growth or dissemination. The differential activation of MAPK and caspase cascades, subsequent IFN- production by CD4 T cells and NK cells and induction of monocyte apoptosis may determine the M. avium pathogenicity. Evaluation of caspases cascade activation in human monocytes following infection with pathogenic and non-pathogenic M. avium strains and the relationship with M. avium pathogenicity and monocyte apoptosis, the roles of MAPK pathways in regulation of intracellular M. avium replication in human monocytes, and proximal mechanisms of IFN- induction by stimulation with M. avium, in terms of expression of IFN- inducing cytokines (IL-12 and IL-18) and the relationship with caspase and MAP kinase activation and apoptosis will be studied. In addition, my current projects also examine the effect of M. avium antigens on monocyte and T cell functions. This involves identification of protein antigens which may be associated with M. avium virulence and the intracellular growth capacity, and the expression of IFN- and IFN- inducing cytokines (IL-12 and IL-18) by human mononuclear phagocytes after stimulation with M. avium antigens. The described study will provide a foundation for additional future work to correlate mycobacterial pathogenesis with the expression of either structural or secreted mycobacterial antigens.

My research involves studies of protective human immunity to Mycobacterium tuberculosis and of evaluation of the virulence M. tuberculosis in human model systems. Current studies focus on the ability of lymphocytes to limit intracellular growth of virulent M. tuberculosis within blood monocytes and alveolar macrophages. In particular, these studies include delineation of which lymphocyte populations are capable of mediating these protective responses, and investigation of both the cytokine-dependent and contact-dependent aspects of these responses. We will also be investigating the ability of M. tuberculosis-specific immune responses to be mobilized to the lungs of PPD-positive subjects. Studies of virulence of M. tuberculosis involve the use of intracellular growth within blood monocytes and alveolar macrophages as an assay for virulence. Studies involve both assessment of the alterations in intracellular growth seen in recombinant organisms in which specific candidate virulence genes have been disrupted, and comparison of the growth of clinical isolates of M. tuberculosis obtained from well-characterized households in Uganda.

Primary Research Interest: Study of the basis for the dysregulation of the immune response during human tuberculosis with specific focus on cytokine responses to M.tuberculosis and its components, and mononuclear cell activation, and mononuclear phagocytic effector mechanisms. Also, understanding the immunopathogenesis of M. tuberculosis infection through analysis of both the host and the organism gene expression in infected monocyte/macrophages from different populations of M.tuberculosis infected and naďve individuals.

Second Research Interest: Study of the impact of tuberculosis on HIV disease with specific focus on mechanisms by which activation of mononuclear cells duringtuberculosis and by M. tuberculosis and its products enhance expression of HIV by latently or newly infected cells. Study of how M. tuberculosis and tuberculosis undermines anti-HIV immune responses in dually infected individuals, and how HIV evolves during HIV/TB.

My research focuses on using randomized controlled clinical trials as a mean to explore the mechanisms of immune reconstitution in patients infected by HIV who start potent antiretroviral therapy. Study immune responses in subjects coinfected with HIV and hepatitis C. Study the effects of IFN-(treatment on HCV-specific immune responses.

Dr. Whalen's research focuses on the epidemiology of tuberculosis and the interactions between HIV and M. tuberculosis. His current projects include a community-based study of tuberculosis transmission in Ugandan households and a randomized clinical trial of prednisolone immunotherapy in HIV-associated tuberculosis. Other research interests include clinical evaluation of tuberculosis vaccines, sexually transmitted diseases as a cofactor in HIV infection, and HIV-related malignancy. He has expertise in epidemiologic study designs and statistical analysis of epidemiologic data.

My research focuses on understanding the molecular and cellular mechanisms underlying dysfunctional host responses to infectious diseases. This translational research emphasizes the use of mouse models to identify mechanisms that can then be confirmed in human studies. My long term goal is to identify and validate immuno-restorative therapies for use in chronic infectious disease and in severely ill patients with clinical “immune paralysis”.

Murine leishmaniasis: A widely applicable model of chronic intracellular infection wherein cure and progression of disease are regulated by different classes of T cell response. Healing or progression of cutaneous infection with Leishmania major is determined by reciprocal expansions of CD4+ T cells producing Th1 (IFN-g) or Th2 (IL-4) cytokines, respectively. Because these outcomes are highly polarized and consistently reproducible, this model is an excellent system for defining the in vivo significance of immunologic responses. Previous work in my lab defined the protective immunoregulatory effects of interleukin-12 (IL-12) treatment, demonstrated the importance of endogenous IL-12 in cure and identified activated dendritic cells as the source of this cytokine. I am currently funded by both NIH and VA grants to design immunotherapeutic strategies for the cure of established leishmaniasis. Successful approaches to date have included treatment with CD40 activating agents, dendritic cell growth factors (flt3 ligand) and a unique method of immune reconstitution, wherein cytotoxic anti-CD4 antibodies are used to transiently deplete dysfunctional T cell responses and cytokine therapy is used to re-establish curative CD4+ T cell immune responses.

MURINE endotoxin tolerance: a model for clinical immune paralysi. We previously defined the pathologic significance of IL-12 and IFN-g synthesis in acute endotoxemia More recently, we shown marked attenuation of the IL-12/IFN-g cytokine response as part of “endotoxin tolerance”, a transient state of “immune paralysis” that follows sublethal endotoxin exposure. Relevant defects appear within the innate cellular immune response and include the specific downregulation of IL-12 production by dendritic cells and the loss of IL-12 responsiveness by the NK cells responsible for IFN-gamma production during acute infection. Ongoing, NIH-funded studies are addressing whether similar molecular mechanisms are responsible for similar immune defects --termed “immune paralysis”--in severely ill patients. Long term goals are to identify if immunotherapies that reverse these defects will prevent nosocomial infection without resort to resistance-inducing antibiotic prophylaxis.

The overall objective of this research is to advance our understanding of how host genetic and immunologic variance influences the outcome of major parasitic diseases, particularly malaria and lymphatic filariasis. Tools of molecular genetics (e.g., PCR-based methods of genotyping microsatellite and other polymorphic markers), immunology (e.g., cytokine ELISAs, HLA-tetramer binding to T-cell receptors expressed by CD8 and CD4 T-cells), and epidemiology are applied to population-based studies of falciparum and vivax malaria and human bancroftian filariasis. The laboratory-based tools are applied to endemic populations in Kenya and Papua New Guinea. Specific projects involve investigations for which the goals are to: 1) Identify how HLA class I-restricted T-cell responses are related to acquired immunity to pre-erythrocytic stages of Plasmodium falciparum. Related objects include identification of non-synonymous mutations in epitope-encoding regions of P. falciparum genes that account for variability of responses in endemic populations. This work is done in collaboration with research and governmental agencies in Kenya and Papua New Guinea; 2) Extend our understanding of vivax malaria is involved in natural selection of red cell polymorphisms that ameliorate malaria infection. This work involves molecular characterization of Duffy blood group and other erythroid polymorphisms (e.g., mutations in spectrin and other integral membrane proteins) that influence blood-stage infection. The work is conducted in Cleveland and Papua New Guinea; 3) Establish the role of allergic-type T-cell immunity in the pathogenesis of lymphatic filariasis. This project examines the correlation between filarial-specific T-cell responses and lymphatic pathology and transmission intensity by local Anopheline mosquito vectors in an endemic area of Papua New Guinea. It is closely integrated with other work that involves testing the feasibility of eradication of lymphatic filariasis through community-based annual treatment with anti-filarial drugs.

Dr. Charles King's research focuses on control of morbidity due to chronic parasitic infections. Two research programs have been established in Coastal Kenya to examine the effects of drug therapy on reversal of disease due to S. haematobium, and to investigate the hereditary risk for parasite infection and associated urinary tract disease. Additional ecological studies will be examining the influence of human-mediated environmental change on the kinetics of schistosome transmission through vector snails. PCR detection of early snail infection and spatial analysis of transmission patterns can then used to develop predicitve models of snail-to-human-to-snail transmission, in order to design better population-based approaches for disease control.

Dr. King's research interest include:

-Immunological mechanisms of granulomatous inflammation in non-human primates

My primary research interest is the immunological mechanisms underlying the pathogenesis of onchocerciasis (river blindness). The parasitic nematode that causes this disease, Onchocerca volvulus infects an estimated 17 million individuals in west and central Africa, the Middle East and Central America. Disease occurs as a result of the host response to dead and degenerating worms in the skin and the cornea, and is characterized by the presence of eosinophils, neutrophils and T cells. The overall goal of my research is to characterize the inflammatory response underlying corneal and dermal immunopathology in infected individuals and using murine models. In collaboration with the World Health Organization onchocerciasis control program in West Africa, we are investigating the role of chemokines in onchocercal skin disease and have identified at least one chemotactic cytokine that is associated with disease (J. Infect Dis 1999.180:1394). We are also using murine models of onchocercal skin and corneal disease to identify and characterize the molecular basis for inflammatory cell extravasation from the blood. Our most recent studies have identified a role for immune complexes in recruitment of neutrophils and eosinophils to the cornea, and development of corneal opacification (J. Immunol. 1999.163:4970). We are therefore focusing on regulation of inflammatory cell recruitment to the cornea, and are examining the potential role of chemokines, chemokine receptors, vascular cell adhesion molecules and complement. Although our studies are directed at understanding the immunopathogenesis of onchocerciasis, our observations clearly have broader implications for other allergic disorders and for other ocular diseases in which neutrophils and eosinophils are implicated.

Dr. Zimmerman's research interests are in Human and Malaria genetics, Susceptibility and resistance to infectious disease, and Evolution of parasite and host relationships.

Research Interest: Clinical HIV including the impact of age on HIV disease progression; Clinical HIV and General ID.

Research or Clinical Interest: HIV and Nosocomial Infections

Research or Clinical Interest: HIV, Endocarditis, Osteomyelitis

Assistant Professor of Medicine