CONTENTS
Review
- Lipoxins and Aspirin-Triggered 15-epi-Lipoxins are Endogenous Components of Antiinflammation: Emergence of the Counterregulatory Side
CHARLES N. SERHAN (Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA)Abstract. Eicosanoids are known to play important roles in cell-cell communications and as intracellular signals that are critical components of multi-cellular responses such as acute inflammation and reperfusion injury. Recent findings have given rise to several new concepts that are reviewed here regarding the generation of eicosanoids and their impact in inflammation. Lipoxins (LX) are trihydroxytetraene-containing eicosanoids that can be generated within the vascular lumen during platelet-leukocyte interactions and at mucosal surfaces via leukocyte-epithelial cell interactions. During these cell-cell interactions, transcellular biosynthetic pathways are used as major LX biosynthetic routes, and thus, in humans, LX are formed in vivo during multi-cellular responses such as inflammation, atherosclerosis, and in asthma. This branch of the eicosanoid cascade generates specific tetraene-containing products that serve as stop signals, in that they regulate key steps in leukocyte trafficking and prevent leukocyte-mediated acute tissue injury. Of interest here are recent results indicating that aspirin’s mechanism of action also involves the triggering of novel carbon 15 epimers of LX or 15-epi-LX that mimic the bioactions of native LX. Here, an overview of these recent developments is presented, with a focus on the cellular and molecular interactions of these novel antiinflammatory lipid mediators.
Keywords: antiinflammation; lipids; leukocytes; signal transduction; resolution mediators
- Evasion of Host Immune Surveillance by Hepatitis C Virus: Potential Roles in Viral Persistence
JONATHAN P. MOORMAN (1)(2), MYUNGSOO JOO (2) and YOUNG S. HAHN (2) – (1) Divisions of Geographic Medicine and Infectious Diseases, University of Virginia School of Medicine, Box 485, Charlottesville, Virginia 22908, USA, (2) Beirne B. Carter Center for Immunology Research, University of Virginia Health Sciences Center, Box MR4-4021, Charlottesville, Virginia 22908, USAAbstract. Hepatitis C virus (HCV) is a major human pathogen that causes mild to severe liver disease worldwide. This positive strand RNA virus is remarkably efficient at establishing chronic infections. In order for a noncytopathic virus such as HCV to persist, the virus must escape immune recognition or evade host immune surveillance. Immune escape via the hypervariable region of the E2 envelope protein has been postulated as one mechanism for HCV persistent infection. Such hypervariability within the E2 protein may be under selective pressure from protective B cell or T cell responses and be able to escape immune recognition by rapid mutation of antigenic site. In addition to antigenic variation, HCV may also suppress immune response, leading to dampening of cellular immunity. This is supported by recent studies in our laboratory demonstrating that the HCV core protein can suppress host immune responses to vaccinia virus by downregulating viral specific cytotoxic T lymphocyte (CTL) responses and cytokine production. An understanding of the mechanisms behind HCV persistence will provide a basis for the rational design of vaccines and novel therapeutic agents targeting human HCV infection.
Keywords: hepatitis C virus; persistence; viral quasispecies; immune evasion
- Peptide Loading of Nascent MHC Class I Molecules
STANISLAV VUKMANOVIĆ, MIRJANA LILIĆ, FABIO R. SANTORI, SANDRA DEMARIA and KIMARY KULIG (Michael Heidelberger Division of Immunology, Department of Pathology, and Kaplan Coprehensive Cancer Center, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA)Abstract. A critical molecular interaction during assembly of the major histocompatibility complex (MHC) class I molecules takes place between the heavy chain and the transporter-associated with antigen-processing (TAP) complex. The recent mapping of regions of the heavy chain involved in the binding to TAP suggests a complex molecular interaction essential for the cell surface expression of the MHC class I. The advances made in understanding the TAP-MHC class I interaction are reviewed and discussed here.
Keywords: MHC class I; antigen processing; TAP; CD8+ cells; cytotoxic T lymphocytes.
- Human Antibody Expression in Transgenic Mice
MARIANNE BRÜGGEMANN (Laboratory of Developmental Immunology, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK)Abstract. Human antibody repertoires can be created in transgenic mice following the introduction of human immunoglobulin heavy and light chain genes in their germline configuration. Transgene constructs or transloci have been obtained by plasmid assembly, cloning in yeast artificial chromosomes, and the use of chromosome fragments. Translocus integration and maintenance in transgenic mouse strains has been achieved by pronuclear DNA injection into oocytes and various transfection methods using embryonic stem cells. The human DNA segments rearrange faithfully in the mouse and produce extensive V(D)J combinations. Specific human monoclonal antibodies of high affinity for use in therapeutic applications have been produced from these translocus mice.
Keywords: human antibody repertoires; transgenesis; human monoclonal antibodies; embryonic stem cell manipulation
- The Search for Novel Adjuvants for Early Life Vaccinations: Can “Danger” Motifs Show Us the Way?
JIRI KOVARIK and CLAIRE-ANNE SIEGRIST (World Health Organization Collaborating Centre for Neonatal Vaccinology, Departments of Pathology and Pediatrics, University of Geneva Medical School, Geneva, Switzerland)Abstract. Potent but safe adjuvants are required to circumvent the many limitations of the newborn immune system to induce rapidly effective and long lasting immunity to subunit vaccines. By the use of pattern recognition receptors, antigen-presenting cells (APC) can very efficiently be activated by “danger” motifs expressed by various pathogens. APC activated by “danger” motifs, such as immunostimulatory sequences of bacterial DNA, can not only transmit the activation signal from the innate immunity to the adaptive compartment, but also shape the antigen-specific immune responses. Molecules or compounds expressing “danger” motifs could, therefore, be considered for use as adjuvants for subunit vaccines. In this review, the authors discuss the promises and potential drawbacks that such novel adjuvants could hold for their use in experimental and clinical early life vaccinations.
Keywords: vaccines; adjuvants; newborns; infants
- CD89: the Human Myeloid IgA Fc Receptor
H. CRAIG MORTON and PER BRANDTZAEG (Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, University of Oslo, The National Hospital, Rikshospitalet, 0027 Oslo, Norway)Abstract. CD89 (FcalphaRI) is the human myeloid IgA Fc receptor expressed on cells, such as neutrophils, eosinophils and monocytes/macrophages. Cross-linking of CD89 on these cells, by IgA-opsonised particles (e.g. bacteria, viruses) or anti-CD89 monoclonal antibodies, can trigger various immunological effector functions which are generally protective but may also cause harm to the body. CD89 is a transmembrane glycoprotein that binds both subclasses of IgA in all its molecular forms (i.e. monomeric, dimeric and secretory IgA) via a region of its membrane-distal EC1 domain. DNA studies have shown that the CD89 gene is located within the newly described leukocyte receptor cluster (LRC) on chromosome 19. CD89 is more closely related to the KIR and MIR proteins, whose genes are also found in the LRC, than to other human Fc receptors (FcRs). On myeloid cells, CD89 is able to associate with the immunoreceptor tyrosine-based activation motif (ITAM)-containing the FcR gamma chain, which is responsible for intracellular signaling via CD89. Recently, it has been suggested that some cells express CD89 in a form that does not associate with the FcR gamma chain. Although the biological relevance of this observation is not yet clear, it may explain certain anti-inflammatory/inhibitory effects attributed to IgA. Here we review current knowledge concerning the genetics, structure and biological function of CD89.
Keywords: CD89; FcalphaR; FcalphaRI; IgA; Fc receptor; myeloid
- Immune-Endocrine Interactions of the Hypothalamus-Pituitary-Thyroid Axis: Integration, Communication and Homeostasis
MATTHEW D. ARMSTRONG and JOHN R. KLEIN (Department of Biological Science and the Mervin Bovaird Center for Studies in Molecular Biology and Biotechnology, University of Tulsa, Tulsa, OK, USA)Abstract. The immune and neuroendocrine systems are two essential physiological components of mammalian organisms. Although each is primarily committed to a set of tasks involved, on the one hand, in the protection from infection and disease, and on the other hand, in the regulation of metabolism and other physiological activities, there is also evidence indicating that active and dynamic collaborations exist between those systems in the execution of their designated functions. These interactions occur at many stages of embryonic and neonatal development, and they are a continual part of the normal homeostatic balance needed to maintain health. The present review discusses various historical and contemporary perspectives of immune-endocrine interactions involving the hypothalamus-pituitary-thyroid axis, and offers a hypothesis of how this aspect of the neuroendocrine system participates directly in the immune response to antigenic challenge, infection and disease.
Keywords: immune-endocrine; hormone; antigen-presenting cells; pituitary-thyroid; lymphocytes; immunity
Cellular Immunology
- Involvement of Beta2-Microglobulin in CD69 Expression on T Cells
LESZEK PĄCZEK, BOŻENA CZARKOWSKA-PĄCZEK, GRAŻYNA KORCZAK-KOWALSKA, PIOTR WIERZBICKI, IRENA BARTŁOMIEJCZYK and ANDRZEJ GÓRSKI (The Transplantation Institute, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland)Abstract. Beta2-Microglobulin (beta2M) is the light chain of the class I HLA molecule. The serum level of beta2M is elevated in various diseases including lymphoma, inflammation, viral infections and chronic renal dysfunction. The present study addressed the possible influence of beta2M on T lymphocyte activation in vitro. Peripheral blood mononuclear cells from a group of 17 healthy subjects were examined. Stimulation with OKT3 and fibronectin in combination with 30 mg beta2M/dl resulted in a two-fold increase of cell proliferation. A similar effect was observed when OKT3 and collagen I were applied as well as when OKT3 and collagen IV were used as costimulation to T cells. The CD69 expression, measured by flow cytometry was significantly enhanced above the control level (1.52 ± 1.03% vs 33.21 ± 20.26%, p<<0.01, control group and 30 mg beta2M/dl, respectively). Together, these observations suggest that beta2M may play a role in modulating lymphocyte proliferation, possibly through modification of the CD69 molecule.
Keywords: beta2-microglobulin; mononuclear cells; proliferation; CD69
- In Vitro and in Vivo Study of the Expression Vector Encoding Vascular Endothelial Growth Factor
MACIEJ MAŁECKI, MAŁGORZATA PRZYBYSZEWSKA and PRZEMYSŁAW JANIK (Department of Cell Biology, Cancer Center, Roentgena 5, 02-781 Warsaw, Poland)Abstract. Vascular endothelial growth factor (VEGF) is an angiogenic cytokine with potential therapeutic applications in human diseases. It is a mitogen primarily for endothelial cells. The transfer of the cDNA encoding VEGF to ischemic tissues, which cannot be revascularized otherwise, represents a novel and promising approach to the treatment of vascular disorders. In this work the VEGF165 cDNA was cloned into the expression vector pSecTag2B. The activity of the construct was studied in cell culture as well as in vivo. Western blotting study showed that the cells transfected with the vector secreted significantly higher amounts of VEGF to the culture medium than the non-transfected cells. In vivo study revealed an increased number of new vessels in animals injected with vector encoding VEGF as compared with empty plasmid. Also, tumor cells transfected with the VEGF plasmid exhibited extensive vascularization.
Keywords: angiogenesis; VEGF; gene therapy
Various
- Modification of Collagen Film by Certain Chemical Agents
EWA LESIAK-CYGANOWSKA, DARIUSZ ŚLADOWSKI and JANUSZ KOMENDER (Department of Transplantology and Central Tissue Bank, Center of Biostructure Research, Warsaw Medical University, Chałubińskiego 5, 02-004 Warsaw, Poland)Abstract. Morphological changes and the content of free carboxyl groups in bovine collagen (type I) film under the influence of trypsin, hydrochloric acid (HCl) and ethylenediaminetetraacetic acid (EDTA) were studied. Incubation with trypsin and HCl was found to cause some delamination of the film and the appearance of some low-density spots. Incubation with EDTA did not cause any morphological changes. A high concentration of free carboxyl groups (10-fold higher than in control) was seen after incubation with trypsin.
Keywords: collagen modification
- In Vitro Culture of Human Epithelial Cells on a Modified Xenogenic Collagen Support
EWA LESIAK-CYGANOWSKA (1), DARIUSZ ŚLADOWSKI (1), EWA JANKOWSKA (2) and JANUSZ KOMENDER (1) – (1) Department of Transplantology and Central Tissue Bank, Centre of Biostructure Research, Warsaw Medical University, Chałubińskiego 5, 02-004 Warsaw, Poland, (2) Department of Electron Microscopy, Centre of Biostructure Research, Warsaw Medical University, Chałubińskiego 5, 02-004 Warsaw, Poland
Abstract. Human epithelial cells (HeLa, HaCaT, NHK) were cultured in vitro on chemically modified collagen membranes. Adhesion to the support was measured by estimation of the percentage of adhering 51Cr-labeled cells. Proliferation was estimated with the XTT test. Morphological observations of cells growing on HCl-treated collagen were performed using histological and electron microscopic techniques. HCl and trypsin-modified xenogenic collagen was found to be a good support for human cells in vitro. EDTA-incubated collagen enhanced neither adhesion nor proliferation. The best adhesion and proliferation were found on HCl-treated collagen, depending, however, on the kind of cells.
Keywords: collagen modification; keratinocytes growth