CONTENTS
Review
- Apoptosis in Human Polymorphonuclear Leukocytes: Searching for a Genetic Roadmap
Scott D. Kobayashi and Frank R. DeLeo (Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA)Abstract. Polymorphonuclear leukocytes (PMNs or neutrophils) are essential components of the innate immune system in humans and function primarily to eliminate invading microorganisms. Neutrophil influx to sites of infection is desirable because it also initiates an inflammatory response. Paradoxically, PMNs are also intimately associated with inflammatory disease. As part of normal neutrophil turnover in humans and to limit inflammatory potential, PMNs undergo programmed cell death or apoptosis. Several host factors, including cytokines and growth factors, are capable of extending neutrophil survival, and thus capacity to fight infection. On the other hand, phagocytosis of bacterial pathogens generally accelerates PMN apoptosis. Due in part to the extensive complexity of programmed cell death, relatively little is known about signaling pathways that govern these processes in PMNs. Recently, microarray strategies have been employed to gain an understanding of these processes in activated PMNs, and new evidence indicates that gene transcription is important in the regulation of neutrophil apoptosis and thus inflammation. A series of provocative discoveries led to the hypothesis that neutrophil programmed cell death is the result of an apoptosis differentiation program, a final stage of transcriptionally regulated PMN maturation or hematopoietic differentiation. Further characterization of the apoptosis differentiation program and associated biochemical pathways in mature PMNs will likely yield important insights into the resolution of inflammation and infection.
Keywords: neutrophil; apoptosis; gene transcription; inflammation.
- BH3-Only Proteins: the Lords of Death
Aarne Fleischer, Angelita Rebollo and Verónica Ayllón (Laboratoire d’Immunologie Cellulaire et Tissulaire U543 INSERM, Bâtiment CERVI, Hôpital Pitié-Salpetriere, 83 Bd de l’Hôpital F-75651 Paris Cedex 13, France)Abstract. Although the mechanisms by which Bcl-2 family proteins control the apoptotic machinery of the cell are not fully understood, it becomes clear that the role of BH3-only proteins consists in serving as sensors or sentinels of cellular damage, transducing the apoptotic stimuli to the mitochondria. For this reason, mammalian cells have developed several strategies for their strict regulation throughout evolution. This review aims to highlight the different ways by which BH3-only proteins are controlled, including transcriptional regulation, post-translational modifications and subcellular localization.
Keywords: apoptosis, Bcl-2, BH3-only proteins, transcriptional regulation, post-translational modifications.
- Viral Modulation of Cell Death by Inhibition of Caspases
Uwe Cassens (Institute of Transfusion Medicine, University of Muenster, D-48149 Muenster, Germany), Grzegorz Lewinski (Unit of Surgery, Municipal Hospital, 38-300 Gorlice, Poland), Ajoy K. Samraj (Institute of Molecular Medicine, University of Duesseldorf, D-40225 Duesseldorf, Germany), Horst von Bernuth (Children’s University Clinic, Laboratory for Clinical Research, D-01307 Dresden, Gemany), Heinrich Baust (Department of Radiotherapy, University of Ulm, D-89070 Ulm, Germany), Khashayarsha Khazaie ((Department of Cancer Immunology and Aids, Dana Farber Cancer Institute/Harvard Medical School, Boston, MA 02115, USA) and Marek Los (Institute of Experimental Dermatology, University of Muenster, D-48149 Muenster, Germany)Abstract. Caspases are key effectors of the apoptotic process. Some of them play an important role in the immune system, being involved in proteolytic maturation of the key cytokines including interleukin-1beta (IL-1beta) and interleukin-18 (IL-18). The latter directs the production of interferon gamma (IFN-gamma). Among pathogens, particularly viruses express various modulators of caspases that inhibit their activity by direct binding. By evading the apoptotic process viruses can better control their production in the infected cell, and avoid the attack of immune system. Targeting of the maturation of the key cytokines involved in the initiation of (antiviral) immune response helps to avoid the recognition and eradication by the immune system. The three main classes of caspase inhibitors frequently found among viruses include serpins (CrmA/SPI-2), viral IAPs (vIAPs) and p35. Their molecular mechanism of action, structure and the overall influence on cellular physiology is discussed in the review below.
Keywords: CrmA; IAP; p35; caspase; granzyme B.
- Immune Mechanisms Contributing to Spontaneous Acceptance of Liver Transplants in Rodents and their potential for clinical transplantation
Marcel den Dulk1, 2 and G. Alex Bishop1 (1AW Morrow Gastroenterology and Liver Laboratory, Centenary Institute, Royal Prince Alfred Hospital and Sydney University, Sydney, Australia and 2Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands)Abstract. The fate of organ transplants between unrelated individuals of the same species is almost always to be rejected, unless the recipient receives immunosuppressive drugs. Liver transplants are an exception, as in a number of animal models, they are often accepted without requiring any treatment. Several mechanisms have been proposed for liver transplant acceptance including: the vascular structure of the liver which allows interaction between naive T cells and liver parenchymal cells; the atypical leucocyte populations of the liver particularly immature dendritic cells; neutralisation of rejection by donor soluble MHC antigen; establishment of microchimerism by donor haematopoietic stem cells and death by “neglect” of recipient T cells in response to inappropriate activation by donor liver leucocytes. Although all these mechanisms may contribute to liver acceptance to some degree, an important finding is that liver acceptance appears to be mainly due to donor leucocytes transplanted with the liver. In combination with the observation of rapid T cell activation followed by their death after liver transplantation, these findings have identified a prominent role for donor leucocyte-induced deletion of liver-reactive T cells. These findings suggest novel ways to explore improved treatment for transplant patients, including administration of donor leucocytes at the time of transplantation and delay of some components of immunosuppressive drug induction therapy.
Keywords: transplantation tolerance, liver transplantation, graft rejection, graft survival, immunosuppressive agents.
- Molecular Targets for Immunocontraception
Bogdana Stoyka1,2, Alina Domagala1 and Maciej Kurpisz1 (1Institute of Human Genetics, Polish Academy of Sciences, Poznań, Poland, 2 Danylo Halytsky State Medical University, Lviv, Ukraine)Abstract. An effective contraceptive is necessary in the countries where limiting population growth has become a public policy imperative. Main antigenic targets for contraceptive vaccine development can be listed as following: 1) sperm antigens; 2) zona pellucida antigens; 3) gonadotrophin-releasing hormone; 4) chorionic gonadotrophin; 5) other protein/peptide hormones (follicle-stimulating hormone, luteinising hormone, luteinizing hormone – releasing hormone); 6) gonadal steroid hormones. New techniques such as an application of monoclonal antibodies, hybridoma and DNA recombinant technologies became useful in search for contraceptive candidates. Current state of development of contraceptive vaccines based on specific antigenic targets and trials in animal/human models are presented in this article.
Keywords: immunocontraception; sperm; zona pellucida; hormonal antigenic targets.
Clinical Immunology
- Individual Differentiation of Innate Antiviral Immunity in Humans; the Role of Endogenous Interferons and Tumor Necrosis Factor in the Immunity of Leukocytes
Beata Orzechowska, Zenon Antoszków and Zofia Błach-Olszewska (Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-112 Wrocław, Poland)Abstract. The natural antiviral immunity of human lymphocytes, leukocyte from peripheral blood and whole-blood cultures was studied using the method of infection with two viruses belonging to different taxonomic groups, vesicular stomatitis virus (VSV) and encephalomyocarditis virus (EMCV). The kinetics of virus replication in both kinds of cultures and the dependence of culture infection on pre-infection incubation time were studied. When the cultures were infected immediately after preparation, most of them were found to be resistant to the viruses. However, when they were infected after several (1-5) days of incubation, VSV and EMCV multiplied in the cultures to high titers. The time of losing the resistance was individually differentiated. The results indicate the presence of a non-specific antiviral immunity characteristic for individuals. The antiviral immunity of healthy donors was compared with that of people suffering from recurrent infections of the upper respiratory tract. This latter group expressed statistically significant lower innate immunity than healthy donors. However there were no differences in interferon (IFN) and tumor necrosis factor (TNF) production between these groups. In order to examine the contribution of the endogenous IFNs and TNF alpha in maintaining innate immunity, specific antibodies against IFN alpha, IFN beta, IFN gamma and TNF alpha were added to VSV-infected leukocytes resistant to infection. The antibodies reduced the antiviral resistance in 9 of 16 experiments. The results suggest that both: endogenous interferons and TNF alpha may participate in the constitution of innate immunity, though they are not the only mediators of it.
Keywords: innate immunity; human leukocytes; viral infections, interferons, tumor necrosis factor.
Immunopharmacology
- Effect of Cyclosporin A Used Alone and in Combination with either 2-Chlorodeoxyadenosine or Fludarabine on Normal and Chronic Myelogenous Leukemia Progenitors in Vitro
Anna Korycka and Tadeusz Robak (Department of Hematology, Medical University of Łódź, Pabianicka 62, 93-513 Łódź, Poland)Abstract. We evaluated the influence of cyclosporin A (CsA) used alone or together with new purine nucleoside analogues (PNAs): 2-chlorodeoxyadenosine (2-CdA) and fludarabine (F-ara-A) on the colony growth of normal and chronic myelogenous leukemia (CML) granulocyte-macrophage progenitor cells (CFU-GM) in cultures in vitro. The assay was based on the method described by Iscove et al. in our modification. Specimens of bone marrow were collected from 15 patients with CML in the chronic phase and from 10 hematologically normal patients. CsA at the concentrations of 1, 2 and 4 mg/ml was used alone and at the concentration of 4 mg/ml it was preincubated with MNCs and after 30 minutes PNAs were added to the culture medium. 2-CdA at the concentrations of 5, 10, 20 nM and 0.4, 0.8, 1.6 mM of F-ara-A were used. After 14 days of incubation the colonies were scored under inverted microscope. We observed that CsA used alone at all three concentrations in a statistically significant degree inhibited the colony growth of CML CFU-GM, as compared to the control (p<0.02) and it did not significantly influence the normal colony growth. IC50 for CsA was 3.9 mg/ml in case of normal CFU-GM and 2.7 mg/ml in case of CML CFU-GM. After the use of CsA in combination either with the highest concentrations of 2-CdA or F-ara-A, statistically significant differences, as compared to CsA used alone were observed (p=0.008; p=0.03 for CsA with 2-CdA; and p=0.0007; p=0.005 for CsA with F-ara-A; respectively for normal and CML CFU-GM). However, there were no significant differences between the combinations of drugs and PNAs used alone. In case of the combination of CsA with the highest concentrations of both PNAs significant differences in the colony growth inhibition between normal and CML CFU-GM were observed (p=0.002 and p=0.005, respectively for 2-CdA and F-ara-A). In conclusion, at the used concentrations of the drugs a subadditive action was observed either between CsA and 2-CdA or between CsA and F-ara-A.
Keywords: cyclosporin A; purine nucleoside analogues; chronic myelogenous leukemia; CFU-GM; cultures in vitro.
Immunochemistry
- Immunochemical studies on the O-antigens of Proteus mirabilis O23 and Proteus vulgaris O23
Antoni Różalski1, Andrei V. Perepelov2, Beata Bartodziejska1, Sof’ya N. Senchenkova2, Dorota Babicka1, Wieslaw Kaca1,3 and Yuriy A. Knirel2 (1Department of Immunobiology of Bacteria, Institute of Microbiology and Immunology, University of Łódź, Banacha 12/16, 90-237 Łódź, Poland, 2N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow 111991, Russia, 3Center of Microbiology and Virology, Polish Academy of Sciences, Lodowa 106, 93-232 Łódź, Poland)
Abstract. Analysis by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy demonstrated that the O-specific polysaccharides of P. mirabilis PrK 42/57 and P. vulgaris PrK 43/57 are structurally similar to that of P. vulgaris PrK 44/57 and different from the polysaccharide of P. mirabilis PrK 41/57 studied earlier. The lipopolysaccharides of these strains were tested using enzyme immunosorbent assay, passive hemolysis and Western blot with O-antisera against P. mirabilis 42/57 and P. vulgaris 43/57 and 44/57, as well as with cross-absorbed O-antisera. The chemical and serological data revealed the basis for combining the four strains into Proteus serogroup O23 and division of this serogroup to three subgroups, one for P. vulgaris 43/57 and 44/57 and two others for P. mirabilis 41/57 and 42/57.
Keywords: Proteus mirabilis; lipopolysaccharide; O-specific polysaccharide; O-antigen; structure; serological reactivity.