CONTENTS
Reviews
Immunology of viral co-infections with HIV
John W. Northfield, Gillian Harcourt, Michaela Lucas and Paul Klenerman (Peter Medawar Building For Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK)
Abstract. Increasing clinical evidence is emerging that other persistent viral infections can act as important co-factors affecting the progression of human immunodeficiency virus-1 (HIV-1). It appears that hepatitis C (HCV) and cytomegalovirus (CMV) have a deleterious effect on HIV progression, whereas hepatitis G (GBV-C) benefits HIV-1 progression. At the same time, the aggressive nature of HCV infection in HIV is clearly recognized. Here we discuss this clinical evidence and go on to review scientific work pertaining to these interactions in the context of the known and theoretical immunological effects of these viruses. This is discussed at the level of the generation of adaptive immune responses and their effector functions. It is clear that co-infection with persistent viral infections may pose special problems for the human immune system, as pathogenic effects may not be specific to the actual eliciting virus and can therefore multiply the difficulties faced by host defenses. We also highlight the need for further therapies for HIV/HCV co-infected persons, as this is currently a complex and severe syndrome.
Keywords: HIV; GBV-C; CMV;hepatitis C;T cell; dendritic cell
Full-textPDF downloadStaphylococcal superantigens: do they play a role in sepsis?
Silva Holtfreter and Barbara M. Bröker (Institut für Immunologie und Transfusionsmedizin, Ernst-Moritz-Arndt-Universität Greifswald, Germany)
Abstract. In Staphylococcus aureus, 19 different superantigens (SAgs) have been described. Their genes are all located on mobile genetic elements, such as pathogenicity islands, plasmids, and phages. SAgs bypass conventional antigen recognition by directly cross-linking major histocompatibility complex class II (MHCII) molecules on antigen-presenting cells with T cell receptors. This leads to massive T cell proliferation and cytokine release, which may end in toxic shock syndrome. The role of SAgs in other forms of sepsis is less well defined. In animal models, SAgs and lipopolysaccharide (LPS) very efficiently synergize in the induction of lethal shock, and on the basis of these observations a two-hit model of sepsis has been proposed: LPS or another monocyte stimulus hits first, then SAg or another T cell stimulus hits. In clinical studies, however, evidence for an involvement of SAgs in sepsis has been difficult to obtain. This may have a number of reasons: differences between humans and rodents in their response to LPS and SAg, heterogeneity of SAg combinations in S. aureus clinical isolates, lack of tools to analyze SAg effects in patients, blocking anti-SAg serum antibodies, and MHCII polymorphisms.
Keywords: superantigen; two-hit model sepsis; Staphylococcus aureus; LPS; T cells
Full-textPDF downloadDimerization, ROS formation, and biological activity of o-methoxyphenols
Seiichiro Fujisawa1, Toshiko Atsumi2, Yukio Murakami1 and Yoshinori Kadoma3 (1Department of Oral Diagnosis Meikai University School of Dentistry, Keyakidai, Sakado, Saitama 350-0283, Japan 2 Department of Dental Physiology, Meikai University School of Dentistry, Keyakidai, Sakado, Saitama 350-0283, Japan 3Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan)
Abstract. o-Methoxyphenols are antioxidants widely used in the cosmetic and food industries. Dimers from 1, 2, or 3 were synthesized and their radical-scavenging and biological activities were compared with those of the original or other phenols. Radical-scavenging was evaluated from a kinetic induction period method (IPM). To simulate biomimetic thiolcooxidation with antioxidants, the behavior of mixtures of 1, 2, 4, or catechin with mercaptomethylimidazole (MMI), a thiol was investigated using IPM. Polyphenols 4 and catechin was accompanied by extensive oxygen uptake, suggesting the formation of thiyl radicals from MMI and their reaction with molecular oxygen. In contrast, 1 markedly enhanced radical-scavenging without oxygen uptake, probably because of the formation of EUGQM/MMI-conjugates. 2 showed relatively small oxygen uptake, probably resulting from the predominant formation of benzyl radicals. Intracellular reactive oxygen species (ROS) in cancer cells by 4, but not by compounds 1, 2, 6, 7, 8, 9, and 10 was found, suggesting a possible link between physicochemical oxygen-uptake and intracellular ROS. The induction of apoptosis by 4 in HL-60 cells was accompanied by intracellular ROS. Dimers 6 and 7 inhibited nuclear factor (NF)-?B activation stimulated by lipopolysaccharide (LPS) in RAW 264.7 cells. Also, 6, 7, and 9 inhibited LPS-induced cyclooxygenase-2 expression in RAW 264.7 cells in a dose-dependent manner, whereas 1, 2 and 3 did not. Dimerization of o-methoxyphenols may be a useful tool for the design of drugs to act as potent chemopreventive and anticancer agents.
Keywords: o-methoxyphenols; dimerization; stoichiometric factors; ROS formation; cooxidation of thiol; apoptosis; NF-?B; Cox-2
Full-textPDF downloadRNA interference – significance and applications
Justyna Stanisławska and Waldemar L. Olszewski (Department of Surgical Research and Transplantology, Medical Research Center, Polish Academy of Sciences, Warsaw, Poland)
Abstract. RNA interference (RNAi) is a post-transcriptional, highly conserved process in eukaryotes that leads to specific gene silencing through degradation of the target mRNA. This mechanism is mediated by double-stranded RNA (dsRNA) that is homologous in sequence to the silenced gene. The dsRNA is processed into small interfering RNA (siRNA) by an enzyme called Dicer, and the siRNAs are then incorporated into a multi-component RNA- -induced silencing complex, which finds and cleaves the target mRNA. In plants and worms, amplification of the silencing signal and cell-to-cell RNAi spreading is observed. The proposed biological roles of RNAi include resistance to viruses, transposons (mainly in plants), and the silencing and regulation of gene expression, particularly during development. In developmental gene control, specific small RNAs (micro RNA and small temporal RNA) are involved, which are processed in the same way as dsRNAs but act at the level of translation. RNAi technology has become a powerful tool in functional genomic analyses and may prove to be a useful method to develop highly specific gene-silencing therapeutics against viral infections and cancer in the future.
Keywords: RNA interference; gene silencing; dsRNA; siRNA
Full-textPDF downloadAnti-tumor chemotherapy utilizing peptide-based approaches apoptotic pathways, kinases, and proteasome as targets
Francisco J. Mendoza, Paula S. Espino, Kendra L. Cann, Nicolle Bristow, Kristin McCrea and Marek Los (Manitoba Institute of Cell Biology, CancerCare Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada)
Abstract. The pharmacological sciences are taking advantage of recent discoveries that havedefined the molecular pathways governing apoptosis. These signaling cascades are frequentlyinactivated or distorted by mutations in cancer cells. Peptides derived from criticalinteraction, phosphorylation, or cleavage sites are the preferred leads (starting points)for the development of new drugs. In this review we summarize recent peptide-basedapproaches that target MDM2, p53, NF-?B, ErbB2, MAPK, as well as Smac/DIABLO, IAPBIR domains, and Bcl-2 interaction domains, with a specific focus on the BH3 domain.Separate parts of the review deal with proteasome inhibitors, integrin-derived peptides,and molecules that are being tested for tumor-selective delivery of anticancer drugs(“magic bullet” approach). The proteasome inhibitors and integrin-derived peptides showa variety of effects, targeting not only tumor growth, but also angiogenesis, metastasizingpotential, and other cancer cell functions. The last part of this review describes approachesthat use specific properties (surface receptors, increased enzymatic activities) of cancercells in order to target them specifically. These new generations of anticancer drugs provide the foundations for therapies with fewer side effects and higher efficacy.
Keywords: angiostatin; anti-angiogenic; Bortezomib; Velcade; EGFR; Endostatin; HMR1826 integrins; MDM2; p53
Full-textPDF downloadOriginal Articles
SEB-induced T cell apoptosis in atopic patients – correlation to clinical status and skin colonization by Staphylococcus aureus
Anna Kędzierska1 , Jolanta Kaszuba-Zwoińska2 , Zofia Słodowska-Hajduk2 , Monika Kapińska-Mrowiecka3 , Marzena Czubak3 , Piotr Thor2 , Kinga Wójcik4 and Juliusz Pryjma1,5, (1Department of Microbiology, Institute of Pediatrics, Cracow, Poland 2Chair of Pathophysiology, Collegium Medicum, Jagiellonian University, Cracow, Poland 3Department of Dermatology, Żeromski Hospital, Cracow, Poland 4Department of Microbiology, Faculty of Biotechnology, Jagiellonian University, Cracow, Poland 5Department of Immunology, Faculty of Biotechnology, Jagiellonian University, Cracow, Poland)
Abstract. Introduction: We asked whether in atopic dermatitis (AD) increased T cell apoptosis in staphylococcal enterotoxin B (SEB)-activated cultures of peripheral blood mononuclear cells (PBMCs) is characteristic of the exacerbation of the disease or connected with skin colonization by Staphylococcus aureus.
Materials and Methods: The clinical status of the patients was evaluated using the SCORAD index. The number of bacteria colonizing patients’ skin lesions was determined by the cfu method. Mononuclear cells isolated from peripheral blood were stimulated by SEB and the apoptosis of CD3+ cells in culture was determined by flow cytometry using the monoclonal antibody APO2.7. The cytokine production in the culture supernatants was determined by ELISA and Cytometric Bead Array kits.
Results: T cell apoptosis was increased, while the production of interferon (IFN)-g was reduced in cultures of PBMCs of AD patients during exacerbation. The proportion of CD3+APO2.7+ cells positively correlated with the density of S. aureus recovered from skin lesions, but not with SCORAD index. By contrast, SCORAD index, but not S. aureus density, negatively correlated with IFN-g production. Furthermore it was found that the presence of S. aureus on uninvolved skin distinguishes a group of severe cases with high serum IgE level, increased T cell apoptosis, and reduced production of tumor necrosis factora in SEB- -stimulated cultures.
Conclusions: Among AD patients the increased activation-induced T cell apoptosis observed in SEB- -stimulated cultures is related to skin colonization by S. aureus. The presence of bacteria on uninvolved skin is a feature of a distinct group of AD patients.
Keywords: atopic dermatitis; apoptosis; T cells; Staphylococcus aureus colonization
Full-textPDF downloadAdvanced glycation end-products prepared in solution under high pressure contain epitopes distinct from those formed in the dry reaction at high temperature
Magdalena Staniszewska, Sławomir Jarosz, Marek Jon and Andrzej Gamian
Abstract. Introduction: Advanced glycation end-products play an important role in diseases related to diabetes and aging processes. Model compounds are synthesized in order to prepare the diagnostic and experimental tools for studying the mechanisms of pathogenesis. The objective of the present study was to accelerate glycation and upgrade its efficiency under high-pressure conditions.
Materials and Methods: Aqueous solutions of proteins were kept with carbohydrates under a pressure of up to 850 MPa for several hours. Then the high-pressure glycation (HPG) products were fractionated on a Sephadex G-200 column and characterized with SDS-PAGE and MALDI-TOF mass spectrometry.
Results:The low-molecular-mass fraction of glycated proteins was separated from the two fractions containing high- and intermediate-molecular-mass cross-linked products of glycation. The products were then compared with those obtained with the high-temperature glycation (HTG) procedure carried out in dry conditions with a lyophilized mixture of substrates. The fractionated products were used to prepare rabbit sera.
Conclusions: The immunoblotting experiments showed that the epitopes on the cross-linked glycation products formed in solution under high pressure differed from those originating in dry conditions at high temperature. Sera against the HPG products were specific to homologous material and did not interact with the fractions obtained by HTG. The antibodies against HTG products recognized HTG but not HPG products.
Keywords: glycation; Maillard reaction; high-pressure reaction; high-temperature reaction; antibodies anti-AGE; epitope
Full-textPDF downloadDifferent pro-inflammatory and immunogenic potentials of Propionibacterium acnes and Staphylococcus epidermidis: implications for chronic inflammatory acne
Anna Białecka2 , Monika Mak1 , Rafał Biedroń1 , Małgorzata Bobek1 , Andrzej Kasprowicz2 and Janusz Marcinkiewicz1 (1Department of Immunology, Jagiellonian University Medical College, Cracow, Poland 2Microbiology Laboratory of Autovaccines, Polish Academy of Science, Cracow, Poland)
Abstract. Introduction: Propionibacterium acnes (PA) and Staphyloccocus epidermidis (SE) are two major bacterial strains isolated from acne lesions. Nevertheless, only PA seems to be implicated in the pathogenesis of inflammatory acne vulgaris. Evidence for this, however, remains indirect and the precise role of PA in inflammatory acne is still a matter for conjecture. The aim of this study was to compare some pro-inflammatory and adjuvant properties of PA and SE.
Materials and Methods:To determine some of the pathogenic, immunostimulatory, and pro-inflammatory properties of PA and SE, two experimental models of inflammation were used. In vivo; chronic inflammation was induced by intradermal injection of living bacteria into the ear. In vitro; peritoneal macrophages elicited by the bacteria were examined for their ability to generate reactive oxygen species (ROS), nitric oxide (NO), and cytokines.
Results: PA, but not SE, evoked mild local inflammation of infected ears. Macrophages elicited with PA produced more tumor necrosis factor a and interleukin IL-12 than those inducedwith SE, while SE was a stronger inducer of IL-10 production. Both bacteria equally induced the generation of NO and ROS. In contrast, only PA showed adjuvant properties.
Conclusions: The results of these studies indicate that SE, in contrast to PA, does not exert pro-inflammatory properties. Thus it is unlikely that SE may be implicated in the pathogenesis of inflammatory acne vulgaris.
Keywords: acne vulgaris; Propionibacterium acnes; Staphyloccocus epidermidis; inflammation; TNF-a; IL-10; ROS
Full-textPDF download