151
|
Thangamani S, Higgs S, Ziegler S, Vanlandingham D, Tesh R, Wikel S. Host immune response to mosquito-transmitted chikungunya virus differs from that elicited by needle inoculated virus. PLoS One 2010; 5:e12137. [PMID: 20711354 PMCID: PMC2920837 DOI: 10.1371/journal.pone.0012137] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 07/20/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Mosquito-borne diseases are a worldwide public health threat. Mosquitoes transmit viruses or parasites during feeding, along with salivary proteins that modulate host responses to facilitate both blood feeding and pathogen transmission. Understanding these earliest events in mosquito transmission of arboviruses by mosquitoes is essential for development and assessment of rational vaccine and treatment strategies. In this report, we compared host immune responses to chikungunya virus (CHIKV) transmission by (1) mosquito bite, or (2) by needle inoculation. METHODS AND FINDINGS Differential cytokine expression was measured using quantitative real-time RT-PCR, at sites of uninfected mosquito bites, CHIKV-infected mosquito bites, and needle-inoculated CHIKV. Both uninfected and CHIKV infected mosquitoes polarized host cytokine response to a TH2 profile. Compared to uninfected mosquito bites, expression of IL-4 induced by CHIKV-infected mosquitoes were 150 fold and 527.1 fold higher at 3 hours post feeding (hpf) and 6 hpf, respectively. A significant suppression of TH1 cytokines and TLR-3 was also observed. These significant differences may result from variation in the composition of uninfected and CHIKV-infected mosquito saliva. Needle injected CHIKV induced a robust interferon-gamma, no detectable IL-4, and a significant up-regulation of TLR-3. CONCLUSIONS This report describes the first analysis of cutaneous cytokines in mice bitten by CHIKV-infected mosquitoes. Our data demonstrate contrasting immune activation in the response to CHIKV infection by mosquito bite or needle inoculation. The significant role of mosquito saliva in these earliest events of CHIKV transmission and infection are highlighted.
Collapse
Affiliation(s)
- Saravanan Thangamani
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.
| | | | | | | | | | | |
Collapse
|
152
|
Ndiaye K, Lussier JG, Pate JL. Molecular characterization and expression of DERL1 in bovine ovarian follicles and corpora lutea. Reprod Biol Endocrinol 2010; 8:94. [PMID: 20682045 PMCID: PMC2920863 DOI: 10.1186/1477-7827-8-94] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 08/03/2010] [Indexed: 01/25/2023] Open
Abstract
The endoplasmic reticulum (ER) is a major site of protein synthesis and facilitates the folding and assembly of newly synthesized proteins. Misfolded proteins are retrotranslocated across the ER membrane and destroyed at the proteasome. DERL1 is an important protein involved in the retrotranslocation and degradation of a subset of misfolded proteins from the ER. We characterized a 2617 bp cDNA from bovine granulosa cells that corresponded to bovine DERL1. Two transcripts of 3 and 2.6 kb were detected by Northern blot analysis, and showed variations in expression among tissues. During follicular development, DERL1 expression was greater in day 5 dominant follicles compared to small follicles, ovulatory follicles, or corpus luteum (CL). Within the CL, DERL1 mRNA expression was intermediate in midcycle, and lowest in late cycle as compared to early in the estrous cycle. Western blot analyses demonstrated the presence of DERL1 in the bovine CL at days 5, 11, and 18 of the estrous cycle. Co-immunoprecipitation using luteal tissues showed that DERL1 interacts with class I MHC but not with VIMP or p97 ATPase. The interaction between DERL1 and MHC I suggests that, in the CL, DERL1 may regulate the integrity of MHC I molecules that are transported to the ER membrane. Furthermore, the greater expression of DERL1 mRNA is associated with the active follicular development and early luteal stages, suggesting a role of DERL1 in tissue remodeling events and maintenance of function in reproductive tissues.
Collapse
Affiliation(s)
- Kalidou Ndiaye
- Department of Animal Sciences, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA
- Department of Dairy and Animal Science, Pennsylvania State University, University Park, PA 16802, USA
- Department of Anatomy and Physiology, Kansas State University, 1600 Denison Ave, Manhattan, KS 66506, USA
| | - Jacques G Lussier
- University of Montreal, Faculty of Veterinary Medicine, Saint-Hyacinthe, Quebec J2 S 7C6, Canada
| | - Joy L Pate
- Department of Animal Sciences, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA
- Department of Dairy and Animal Science, Pennsylvania State University, University Park, PA 16802, USA
| |
Collapse
|
153
|
|
154
|
Mercer F, Unutmaz D. The biology of FoxP3: a key player in immune suppression during infections, autoimmune diseases and cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 665:47-59. [PMID: 20429415 DOI: 10.1007/978-1-4419-1599-3_4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Transcription factor FoxP3 belongs to the forkhead/winged-helix family of transcriptional regulators and shares general structural features with other FoxP family members. FoxP3 functions as a master of transcription for the development of regulatory T-cells (Treg cells) both in humans and in mice. Natural genetic mutations ofFoxP3 that disrupt its function in humans result in an autoimmune syndrome called Immune Polyendocrinopathy, Enteropathy, X-linked (IPEX) and in mice, its deletion causes the Scurfy phenotype, with similar pathology. The finding that FoxP3 is required for the development and function of Tregs has led to an explosion of research in determining its regulation and function in the immune system. Understanding the biological properties of FoxP3 has a wide range of implications for immune tolerance, autoimmune disorders, inflammation and immune response to infectious diseases and cancer.
Collapse
Affiliation(s)
- Frances Mercer
- Department of Microbiology, New York University School of Medicine, Smilow Research Center, 522 First Avenue, Smilow Building Rm:1011, New York, New York 10016, USA
| | | |
Collapse
|
155
|
del Rio ML, Bernhardt G, Rodriguez-Barbosa JI, Förster R. Development and functional specialization of CD103+ dendritic cells. Immunol Rev 2010; 234:268-81. [PMID: 20193025 DOI: 10.1111/j.0105-2896.2009.00874.x] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CD103 (alpha(E)) integrin expression distinguishes a population of dendritic cells (DCs) that can be found in many if not all lymphoid and non-lymphoid organs. CD103(+) DCs display distinct functional activities. Migratory CD103(+) DCs derived from skin, lung, and intestine efficiently present exogenous antigens in their corresponding draining lymph nodes to specific CD8(+) T cells through a mechanism known as cross-presentation. On the T cells they prime, intestinal CD103(+) DCs can drive the induction of the chemokine receptor CCR9 and alpha(4)beta(7) integrin, both known as gut-homing receptors. CD103(+) DCs also contribute to control inflammatory responses and intestinal homeostasis by fostering the conversion of naive T cells into induced Foxp3(+) regulatory T cells, a mechanism that relies on transforming growth factor-beta and retinoic acid signaling. This review discusses recent findings that identify murine CD103(+) DCs as important regulators of the immune response.
Collapse
|
156
|
Wanderley JLM, Barcinski MA. Apoptosis and apoptotic mimicry: the Leishmania connection. Cell Mol Life Sci 2010; 67:1653-9. [PMID: 20140747 PMCID: PMC11115723 DOI: 10.1007/s00018-010-0291-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 01/20/2010] [Indexed: 12/16/2022]
Abstract
Different death-styles have been described in unicellular organisms. In most cases they evolve with phenotypic features similar to apoptotic death of animal cells, such as phosphatidylserine (PS) exposure, oligonucleosomal DNA fragmentation, and loss of mitochondrial transmembrane potential, hinting that similar mechanisms operate in both situations. However, the biochemical pathways underlying death in unicellular organisms are still unclear. Host recognition of PS exposed on the surface of unicellular parasites is an important feature of the process of infection and progression of the disease. Here, we discuss data showing that entirely different mechanisms of PS exposure co-exist during the life-cycle of Leishmania amazonensis: in the case of promastigotes, a sub-population dies by apoptosis; in the case of amastigotes, the entire population exposes PS, not necessarily followed by apoptotic death. This phenomenon has been called apoptotic mimicry. The elusive caspase-like activities described in protozoa are also discussed.
Collapse
Affiliation(s)
- João Luiz M. Wanderley
- Division of Experimental Medicine, National Cancer Institute, Rio de Janeiro, Brazil
- Program in Morphological Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcello A. Barcinski
- Departamento de Parasitogia, Universidade de São Paulo (USP), Av. Prof. Lineu Prestes 1374, São Paulo, SP 05508-900 Brazil
| |
Collapse
|
157
|
Grieco FA, Vendrame F, Spagnuolo I, Dotta F. Innate immunity and the pathogenesis of type 1 diabetes. Semin Immunopathol 2010; 33:57-66. [PMID: 20383637 DOI: 10.1007/s00281-010-0206-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 03/18/2010] [Indexed: 12/21/2022]
Abstract
Type 1 diabetes mellitus is an autoimmune disease caused by the immune-mediated destruction of insulin-producing pancreatic beta cells occurring in genetically predisposed individuals, with consequent hyperglycemia and serious chronic complications. Studies in man and in experimental animal models have shown that both innate and adaptive immune responses participate to disease pathogenesis, possibly reflecting the multifactorial pathogenetic nature of this autoimmune disorder, with the likely involvement of environmental factors occurring at least in a subset of individuals. As a consequence, components of both innate and adaptive immune response should be considered as potential targets of therapeutic strategies for disease prevention and cure. Here we review the contribution of innate immune response to type 1 diabetes, with a particular emphasis to Toll-like receptors (TLR) and NK cells.
Collapse
Affiliation(s)
- Fabio Arturo Grieco
- Diabetes Unit, Department of Internal Medicine, Endocrine and Metabolic Sciences and Biochemistry, University of Siena, Siena, Italy
| | | | | | | |
Collapse
|
158
|
Zhi L, Mans J, Paskow MJ, Brown PH, Schuck P, Jonjić S, Natarajan K, Margulies DH. Direct interaction of the mouse cytomegalovirus m152/gp40 immunoevasin with RAE-1 isoforms. Biochemistry 2010; 49:2443-53. [PMID: 20166740 DOI: 10.1021/bi902130j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cytomegaloviruses (CMVs) are ubiquitous species-specific viruses that establish acute, persistent, and latent infections. Both human and mouse CMVs encode proteins that inhibit the activation of natural killer (NK) cells by downregulating cellular ligands for the NK cell activating receptor, NKG2D. The MCMV glycoprotein m152/gp40 downregulates the surface expression of RAE-1 to prevent NK cell control in vivo. So far, it is unclear if there is a direct interaction between m152 and RAE-1 and, if so, if m152 interacts differentially with the five identified RAE-1 isoforms, which are expressed as two groups in MCMV-susceptible or -resistant mouse strains. To address these questions, we expressed and purified the extracellular domains of RAE-1 and m152 and performed size exclusion chromatography binding assays as well as analytical ultracentrifugation and isothermal titration calorimetry to characterize these interactions quantitatively. We further evaluated the role of full-length and naturally glycosylated m152 and RAE-1 in cotransfected HEK293T cells. Our results confirmed that m152 binds RAE-1 directly, relatively tightly (K(d) < 5 microM), and with 1:1 stoichiometry. The binding is quantitatively different depending on particular RAE-1 isoforms, corresponding to the susceptibility to downregulation by m152. A PLWY motif found in RAE-1beta, although contributing to its affinity for m152, does not influence the affinity of RAE-1gamma or RAE-1delta, suggesting that other differences contribute to the RAE-1-m152 interaction. Molecular modeling of the different RAE-1 isoforms suggests a potential site for the m152 interaction.
Collapse
Affiliation(s)
- Li Zhi
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1892, USA
| | | | | | | | | | | | | | | |
Collapse
|
159
|
|
160
|
Linderman JJ, Riggs T, Pande M, Miller M, Marino S, Kirschner DE. Characterizing the dynamics of CD4+ T cell priming within a lymph node. THE JOURNAL OF IMMUNOLOGY 2010; 184:2873-85. [PMID: 20154206 DOI: 10.4049/jimmunol.0903117] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Generating adaptive immunity postinfection or immunization requires physical interaction within a lymph node T zone between Ag-bearing dendritic cells (DCs) and rare cognate T cells. Many fundamental questions remain regarding the dynamics of DC-CD4+ T cell interactions leading to priming. For example, it is not known how the production of primed CD4+ T cells relates to the numbers of cognate T cells, Ag-bearing DCs, or peptide-MHCII level on the DC. To address these questions, we developed an agent-based model of a lymph node to examine the relationships among cognate T cell frequency, DC density, parameters characterizing DC-T cell interactions, and the output of primed T cells. We found that the output of primed CD4+ T cells is linearly related to cognate frequency, but nonlinearly related to the number of Ag-bearing DCs present during infection. This addresses the applicability of two photon microscopy studies to understanding actual infection dynamics, because these types of experiments increase the cognate frequency by orders of magnitude compared with physiologic levels. We found a trade-off between the quantity of peptide-major histocompatibility class II on the surface of individual DCs and number of Ag-bearing DCs present in the lymph node in contributing to the production of primed CD4+ T cells. Interestingly, peptide-major histocompatibility class II t(1/2) plays a minor, although still significant, role in determining CD4+ T cell priming, unlike the primary role that has been suggested for CD8+ T cell priming. Finally, we identify several pathogen-targeted mechanisms that, if altered in their efficiency, can significantly effect the generation of primed CD4+ T cells.
Collapse
Affiliation(s)
- Jennifer J Linderman
- Department of Chemical Engineering, Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | | | |
Collapse
|
161
|
Muller WJ, Jones CA, Koelle DM. Immunobiology of herpes simplex virus and cytomegalovirus infections of the fetus and newborn. ACTA ACUST UNITED AC 2010; 6:38-55. [PMID: 20467462 DOI: 10.2174/157339510790231833] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Immunologic "immaturity" is often blamed for the increased susceptibility of newborn humans to infection, but the precise mechanisms and details of immunologic development remain somewhat obscure. Herpes simplex virus (HSV) and cytomegalovirus (CMV) are two of the more common severe infectious agents of the fetal and newborn periods. HSV infection in the newborn most commonly occurs after exposure to the virus during delivery, and can lead to a spectrum of clinical disease ranging from isolated skin-eye-mucous membrane infection to severe disseminated multiorgan disease, often including encephalitis. In contrast to HSV, clinically severe CMV infections early in life are usually acquired during the intrauterine period. These infections can result in a range of clinical disease, including hearing loss and neurodevelopmental delay. However, term newborns infected with CMV after delivery are generally asymptomatic, and older children and adults often acquire infection with HSV or CMV with either no or mild clinical symptoms. The reasons for these widely variable clinical presentations are not completely understood, but likely relate to developmental differences in immune responses.This review summarizes recent human and animal studies of the immunologic response of the fetus and newborn to these two infections, in comparison to the responses of older children and adults. The immunologic defense of the newborn against each virus is considered under the broader categories of (i) the placental barrier to infection, (ii) skin and mucosal barriers (including antimicrobial peptides), (iii) innate responses, (iv) humoral responses, and (v) cellular responses. A specific focus is made on recent studies of innate and cellular immunity to HSV and CMV.
Collapse
Affiliation(s)
- William J Muller
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | | |
Collapse
|
162
|
Orr MT, Lanier LL. Inhibitory Ly49 receptors on mouse natural killer cells. Curr Top Microbiol Immunol 2010; 350:67-87. [PMID: 20680808 DOI: 10.1007/82_2010_85] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ly49 receptors, which are expressed in a stochastic manner on subsets of murine natural killer (NK) cells, T cells, and other cells, are encoded by the Klra gene family and include receptors with either inhibitory or activating function. All of the inhibitory Ly49 receptors are characterized by an immunoreceptor tyrosine-based inhibitory motif in their cytoplasmic domain, which upon phosphorylation recruits tyrosine or lipid phosphatases to dampen signals transmitted through other activating receptors. Most of the inhibitory Ly49 receptors recognize polymorphic epitopes on major histocompatibility complex (MHC) class I proteins as ligands. Here, we review the polymorphism, ligand specificity, and signaling capacity of the inhibitory Ly49 receptors and discuss how these molecules regulate NK cell development and function.
Collapse
Affiliation(s)
- Mark T Orr
- Department of Microbiology and Immunology and the Cancer Research Institute, University of California, San Francisco, CA, 94143, USA.
| | | |
Collapse
|
163
|
Abstract
The capacity of varicella zoster virus (VZV) to cause varicella (chickenpox) relies upon multiple steps, beginning with inoculation of the host at mucosal sites with infectious virus in respiratory droplets. Despite the presence of a powerful immune defense system, this virus is able to disseminate from the site of initial infection to multiple sites, resulting in the emergence of distinctive cutaneous vesiculopustular lesions. Most recently, it has been proposed that the steps leading to cutaneous infection include VZV infecting human tonsillar CD4(+) T cells that express skin homing markers that allow them to transport VZV directly from the lymph node to the skin during the primary viremia. It has also been proposed that dendritic cells (DC) of the respiratory mucosa may be among the first cells to encounter VZV and these cells may transport virus to the draining lymph node. These various virus-host cell interactions would all need to occur in the face of an intact host immune response for the virus to successfully cause disease. Significantly, following primary exposure to VZV, there is a prolonged incubation period before emergence of skin lesions, during which time the adaptive immune response is delayed. For these reasons, it has been proposed that VZV must encode functions which benefit the virus by evading the immune response. This chapter will review the diverse array of immunomodulatory mechanisms identified to date that VZV has evolved to at least transiently limit immune recognition.
Collapse
|
164
|
Positive selection on apoptosis related genes. FEBS Lett 2009; 584:469-76. [PMID: 20026333 DOI: 10.1016/j.febslet.2009.12.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 12/15/2009] [Accepted: 12/15/2009] [Indexed: 12/23/2022]
Abstract
Apoptosis is a form of programmed cell death crucial for development, homeostasis, immunity, spermatogenesis, and prevention of cancer. Positive selection acting on mammalian apoptosis related genes targets protein interfaces that interact with pathogens and also elements of signaling complexes. Selection appears primarily to be driven by the immune/defense related function of these genes. Moreover, competitive interactions could be driving positive selection among sperm cells, as well as the need for protection against female anti-sperm immune responses. Trade-offs in fitness are expected out of these selective pressures, which could explain the involvement of these genes in various diseases, including cancer.
Collapse
|
165
|
Rimmelzwaan GF, Kreijtz JHCM, Bodewes R, Fouchier RAM, Osterhaus ADME. Influenza virus CTL epitopes, remarkably conserved and remarkably variable. Vaccine 2009; 27:6363-5. [PMID: 19840674 DOI: 10.1016/j.vaccine.2009.01.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/06/2009] [Accepted: 01/08/2009] [Indexed: 01/05/2023]
Abstract
Virus-specific cytotoxic T lymphocytes (CTL) contribute to the control of virus infections including those caused by influenza viruses. Especially under circumstances when antibodies induced by previous infection or vaccination fail to recognize and neutralize the virus adequately, CTL are important and contribute to protective immunity. During epidemic outbreaks caused by antigenic drift variants and during pandemic outbreaks of influenza, humoral immunity against influenza viruses is inadequate. Under these circumstances, pre-existing CTL directed to the relatively conserved internal proteins of the virus may provide cross-protective immunity. Indeed, most of the known human influenza virus CTL epitopes are conserved. However, during the evolution of influenza A/H3N2 viruses, the most important cause of seasonal influenza outbreaks, variation in CTL epitopes has been observed. The observed amino acid substitutions affected recognition by virus-specific CTL and the human virus-specific CTL response in vitro. Examples of variable epitopes and their HLA restrictions are: NP(383-391)/HLA-B*2705, NP(380-388)/HLA-B*0801, NP(418-426)/HLA-B*3501, NP(251-259)/HLA-B*4002, NP(103-111)/HLA-B*1503. In some cases amino acid substitutions occurred at anchor residues and in other cases at T cell receptor contact residues. It is of special interest that the R384G substitution in the NP(383-391) epitope was detrimental to virus fitness and was only tolerated in the presence of multiple functionally compensating co-mutations. In contrast, other epitopes, like the HLA-A*0201 restricted epitope from the matrix protein, M1(58-66), are highly conserved despite their immunodominant nature and the high prevalence of HLA-A*0201 in the population. A mutational analysis of this epitope indicated that it is under functional constraints. Also in influenza A viruses of other subtypes, including H5N1, the M1(58-66) is highly conserved.
Collapse
Affiliation(s)
- Guus F Rimmelzwaan
- Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
166
|
Immune evasion proteins of murine cytomegalovirus preferentially affect cell surface display of recently generated peptide presentation complexes. J Virol 2009; 84:1221-36. [PMID: 19906905 DOI: 10.1128/jvi.02087-09] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
For recognition of infected cells by CD8 T cells, antigenic peptides are presented at the cell surface, bound to major histocompatibility complex class I (MHC-I) molecules. Downmodulation of cell surface MHC-I molecules is regarded as a hallmark function of cytomegalovirus-encoded immunoevasins. The molecular mechanisms by which immunoevasins interfere with the MHC-I pathway suggest, however, that this downmodulation may be secondary to an interruption of turnover replenishment and that hindrance of the vesicular transport of recently generated peptide-MHC (pMHC) complexes to the cell surface is the actual function of immunoevasins. Here we have used the model of murine cytomegalovirus (mCMV) infection to provide experimental evidence for this hypothesis. To quantitate pMHC complexes at the cell surface after infection in the presence and absence of immunoevasins, we generated the recombinant viruses mCMV-SIINFEKL and mCMV-Deltam06m152-SIINFEKL, respectively, expressing the K(b)-presented peptide SIINFEKL with early-phase kinetics in place of an immunodominant peptide of the viral carrier protein gp36.5/m164. The data revealed approximately 10,000 K(b) molecules presenting SIINFEKL in the absence of immunoevasins, which is an occupancy of approximately 10% of all cell surface K(b) molecules, whereas immunoevasins reduced this number to almost the detection limit. To selectively evaluate their effect on preexisting pMHC complexes, cells were exogenously loaded with SIINFEKL peptide shortly after infection with mCMV-SIINFEKA, in which endogenous presentation is prevented by an L174A mutation of the C-terminal MHC-I anchor residue. The data suggest that pMHC complexes present at the cell surface in advance of immunoevasin gene expression are downmodulated due to constitutive turnover in the absence of resupply.
Collapse
|
167
|
Scott I. Degradation of RIG-I following cytomegalovirus infection is independent of apoptosis. Microbes Infect 2009; 11:973-9. [PMID: 19591957 PMCID: PMC2741008 DOI: 10.1016/j.micinf.2009.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 07/01/2009] [Indexed: 01/02/2023]
Abstract
Many viruses have evolved strategies to either evade or hijack host cell immune programs, as a means of promoting their own reproduction. For example, the human cytomegalovirus (HCMV) immediate-early protein vMIA/UL37ex1 inhibits host cell apoptosis, and its expression during infection aids virus replication. Here it is shown that stable expression of vMIA/UL37ex1 reduces cleavage of the innate immune response-proteins MAVS and RIG-I by caspases during apoptosis. Unexpectedly, it is demonstrated that RIG-I, but not MAVS, is degraded during HCMV infection. This process occurs in a non-apoptotic manner, and provides new evidence that HCMV may have evolved a unique strategy to evade RIG-I-mediated immune responses.
Collapse
Affiliation(s)
- Iain Scott
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA.
| |
Collapse
|
168
|
Liu H, Söderhäll K, Jiravanichpaisal P. Antiviral immunity in crustaceans. FISH & SHELLFISH IMMUNOLOGY 2009; 27:79-88. [PMID: 19223016 PMCID: PMC7172356 DOI: 10.1016/j.fsi.2009.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Revised: 01/28/2009] [Accepted: 02/01/2009] [Indexed: 05/27/2023]
Abstract
Viral diseases of shrimp have caused negative effects on the economy in several countries in Asia, South America and America, where they have numerous shrimp culture industries. The studies on the immunity of shrimp and other crustaceans have mainly focused on general aspects of immunity and as a consequence little is known about the antiviral responses in crustaceans. The aim of this review is to update recent knowledge of innate immunity against viral infections in crustaceans. Several antiviral molecules have been isolated and characterized recently from decapods. Characterization and identification of these molecules might provide a promising strategy for protection and treatment of these viral diseases. In addition dsRNA-induced antiviral immunity is also included.
Collapse
Affiliation(s)
- Haipeng Liu
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
- State Key Laboratory of Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen, 361005 Fujian, PR China
| | - Kenneth Söderhäll
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
| | - Pikul Jiravanichpaisal
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
- Molecular Aquatic Biology and Genetic Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Rajdhevee, Bangkok 10400, Thailand
| |
Collapse
|
169
|
Boppana VD, Thangamani S, Adler AJ, Wikel SK. SAAG-4 is a novel mosquito salivary protein that programmes host CD4 T cells to express IL-4. Parasite Immunol 2009; 31:287-95. [PMID: 19493208 DOI: 10.1111/j.1365-3024.2009.01096.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Mosquitoes represent the most important vector for transmitting pathogens that cause human disease. Central to pathogen transmission is the ability to divert the host immune system away from Th1 and towards Th2 responsiveness. Identification of the mosquito factor(s) critical for programming Th2 responsiveness should therefore lead to strategies to neutralize their function and thus prevent disease transmission. In the current study, we used a TCR transgenic adoptive transfer system to screen gene products present in the saliva of the mosquito Aedes aegypti for their ability to programme CD4 T cells to express the signature Th2 cytokine IL-4. The clone SAAG-4 encodes a secreted protein with a predicted size of 20 kDa whose function has previously been uncharacterized. Notably, SAAG-4 reduced host CD4 T cell expression of the signature Th1 cytokine IFN-gamma while simultaneously increasing expression of IL-4. SAAG-4 is therefore the first identified mosquito factor that can programme Th2 effector CD4 T cell differentiation.
Collapse
Affiliation(s)
- V D Boppana
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, Connecticut, USA
| | | | | | | |
Collapse
|
170
|
Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition. Virology 2009; 391:5-19. [PMID: 19570562 DOI: 10.1016/j.virol.2009.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 05/06/2009] [Accepted: 06/01/2009] [Indexed: 11/24/2022]
Abstract
Human cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2-11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein still recognized and lysed mutant virus infected fibroblasts. Yet, suppression of IE1 derived peptide presentation by gpUS2 or gpUS11 was far more pronounced. The results show that gpUS2 and gpUS11 alone only incompletely protect HCMV infected fibroblasts from CTL recognition and underline the importance of studying infected cells to elucidate HCMV immune evasion.
Collapse
|
171
|
Human CMV Infection of Porcine Endothelial Cells Increases Adhesion Receptor Expression and Human Leukocyte Recruitment. Transplantation 2009; 87:1792-800. [DOI: 10.1097/tp.0b013e3181a75a41] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
172
|
Discerning regulation of cis- and trans-presentation of CD8+ T-cell epitopes by EBV-encoded oncogene LMP-1 through self-aggregation. Blood 2009; 113:6148-52. [DOI: 10.1182/blood-2009-02-203687] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractActivation of the nuclear factor–κB pathway by Epstein-Barr virus–encoded latent membrane protein-1 (LMP-1) leads to an up-regulation of the major histocompatibility complex class I antigen–processing pathway. Paradoxically, LMP-1 itself induces a subdominant CD8+ T-cell response and appears to have evolved to avoid immune recognition. Here we show that, although expression of LMP-1 in human cells dramatically enhanced the trans-presentation of CD8+ T-cell epitopes, cis-presentation of LMP-1–derived epitopes was severely impaired. Testing of a series of LMP-1 mutants revealed that deletion of the first transmembrane domain of LMP-1, which prevented self-aggregation, significantly enhanced cis-presentation of T-cell epitopes from this protein, whereas it lost its ability to up-regulate trans-presentation. Interestingly, we also found that cis-presentation of LMP-1 epitopes was rescued by blocking the proteasome function. Taken together, these results delineate a novel mechanism of immune evasion, which renders a virally encoded oncogene inaccessible to the conventional major histocompatibility complex class I pathway limiting its cis-presentation to effector cells.
Collapse
|
173
|
Mans J, Zhi L, Revilleza MJR, Smith L, Redwood A, Natarajan K, Margulies DH. Structure and function of murine cytomegalovirus MHC-I-like molecules: how the virus turned the host defense to its advantage. Immunol Res 2009; 43:264-79. [PMID: 19011767 DOI: 10.1007/s12026-008-8081-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The mouse cytomegalovirus (CMV), a beta-herpesvirus, exploits its large (~230 kb) double-stranded DNA genome for both essential and non-essential functions. Among the non-essential functions are those that offer the virus a selective advantage in eluding both the innate and adaptive immune responses of the host. Several non-essential genes of MCMV are thought to encode MHC-I-like genes and to function as immunoevasins. To understand further the evolution and function of these viral MHC-I (MHC-Iv) molecules, X-ray structures of several of them have been determined, not only confirming the overall MHC-I-like structure, but also elucidating features unique to this family. Future efforts promise to clarify the nature of the molecular ligands of these molecules, their evolution in the context of the adapting immune response of the murine host, and by analogy the evolution of the host response to human CMV as well.
Collapse
Affiliation(s)
- Janet Mans
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10; Room 11N311, 10 Center Drive, Bethesda, MD 20892-1892, USA
| | | | | | | | | | | | | |
Collapse
|
174
|
Mohamed MR, Rahman MM, Lanchbury JS, Shattuck D, Neff C, Dufford M, van Buuren N, Fagan K, Barry M, Smith S, Damon I, McFadden G. Proteomic screening of variola virus reveals a unique NF-kappaB inhibitor that is highly conserved among pathogenic orthopoxviruses. Proc Natl Acad Sci U S A 2009; 106:9045-50. [PMID: 19451633 PMCID: PMC2683884 DOI: 10.1073/pnas.0900452106] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Indexed: 11/18/2022] Open
Abstract
Identification of the binary interactions between viral and host proteins has become a valuable tool for investigating viral tropism and pathogenesis. Here, we present the first systematic protein interaction screening of the unique variola virus proteome by using yeast 2-hybrid screening against a variety of human cDNA libraries. Several protein-protein interactions were identified, including an interaction between variola G1R, an ankryin/F-box containing protein, and human nuclear factor kappa-B1 (NF-kappaB1)/p105. This represents the first direct interaction between a pathogen-encoded protein and NF-kappaB1/p105. Orthologs of G1R are present in a variety of pathogenic orthopoxviruses, but not in vaccinia virus, and expression of any one of these viral proteins blocks NF-kappaB signaling in human cells. Thus, proteomic screening of variola virus has the potential to uncover modulators of the human innate antiviral responses.
Collapse
Affiliation(s)
- Mohamed R. Mohamed
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Masmudur M. Rahman
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610
| | | | | | - Chris Neff
- Myriad Genetics, Salt Lake City, UT 84108
| | | | - Nick van Buuren
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada T6G 2S2
| | - Katharine Fagan
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada T6G 2S2
| | - Michele Barry
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada T6G 2S2
| | - Scott Smith
- World Health Organization Collaborating Center for Smallpox and other Poxvirus Infections, Poxvirus and Rabies Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333
| | - Inger Damon
- World Health Organization Collaborating Center for Smallpox and other Poxvirus Infections, Poxvirus and Rabies Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333
| | - Grant McFadden
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610
| |
Collapse
|
175
|
Novak MT, Bryers JD, Reichert WM. Biomimetic strategies based on viruses and bacteria for the development of immune evasive biomaterials. Biomaterials 2009; 30:1989-2005. [PMID: 19185345 PMCID: PMC2673477 DOI: 10.1016/j.biomaterials.2008.11.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 11/26/2008] [Indexed: 12/30/2022]
Abstract
The field of biomaterials has begun to focus upon materials strategies for modulating the immune response. While certain approaches appear promising, they are currently limited to isolated facets of inflammation process. It is well documented that both bacteria and viruses have highly developed methods for evading the immune system, providing inspiration for a more biomimetic approach to materials design. This review presents the immune evasive tactics employed by viruses and bacteria, and offers suggestions for future directions that apply these principles to design of immune evasive biomaterials.
Collapse
Affiliation(s)
- Matthew T. Novak
- Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC, 27708
| | - James D. Bryers
- Department of Bioengineering, University of Washington, PO Box 355061, 1705 NE Pacific Street, Seattle, WA, 98195
| | - William M. Reichert
- Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC, 27708
| |
Collapse
|
176
|
Franceschini D, Paroli M, Francavilla V, Videtta M, Morrone S, Labbadia G, Cerino A, Mondelli MU, Barnaba V. PD-L1 negatively regulates CD4+CD25+Foxp3+ Tregs by limiting STAT-5 phosphorylation in patients chronically infected with HCV. J Clin Invest 2009; 119:551-64. [PMID: 19229109 DOI: 10.1172/jci36604] [Citation(s) in RCA: 246] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 01/07/2009] [Indexed: 12/22/2022] Open
Abstract
CD4+CD25+Foxp3+ Tregs suppress autoimmune responses. In addition, they limit T cell responses during chronic infection, thereby minimizing T cell-dependent immunopathology. We sought to investigate how Tregs are regulated in the livers of patients chronically infected with HCV, where they control the balance between an adequate protective immune response and suppression of immunopathology. We found that, despite accumulating and proliferating at sites of infection in the livers of patients chronically infected with HCV, Tregs were relatively less expanded than CD4+CD25+Foxp3- effector T cells. The relative lower expansion of intrahepatic Tregs coincided with their upregulation of programmed death-1 (PD-1). PD-1 expression inversely correlated with both Treg proliferation and clinical markers of immune suppression in vivo. Consistent with the possibility that PD-1 controls Tregs, blockade of the interaction between PD-1 and programmed death-1 ligand 1 (PD-L1) enhanced the in vitro expansion and function of Tregs isolated from the livers of patients chronically infected with HCV. Blockade of the interaction between PD-L1 and B7.1 also improved the proliferation of these cells. Interestingly, both PD-1 and phosphorylated STAT-5 were overexpressed in intrahepatic Tregs in a parallel fashion in steady disease conditions, and in an alternate-fluctuating fashion during the course of severe hepatitis reactivation. Notably, PD-L1 blockade upregulated STAT-5 phosphorylation in Tregs ex vivo. These data suggest that PD-L1 negatively regulates Tregs at sites of chronic inflammation by controlling STAT-5 phosphorylation.
Collapse
Affiliation(s)
- Debora Franceschini
- Dipartimento di Medicina Interna, Sapienza Università di Roma, Policlinico Umberto I, viale del Policlinico 155, Rome, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
177
|
Rallón NI, López M, Soriano V, García-Samaniego J, Romero M, Labarga P, García-Gasco P, González-Lahoz J, Benito JM. Level, phenotype and activation status of CD4+FoxP3+ regulatory T cells in patients chronically infected with human immunodeficiency virus and/or hepatitis C virus. Clin Exp Immunol 2009; 155:35-43. [PMID: 19076827 DOI: 10.1111/j.1365-2249.2008.03797.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
CD4(+) regulatory T (T(reg)) cells have been involved in impaired immunity and persistence of viral infections. Herein, we report the level, phenotype and activation status of T(reg) cells in patients chronically infected with human immunodeficiency virus (HIV) and/or hepatitis C virus (HCV). Expression of CD25, CD45RA, CD27, CD127 and CD38 was assessed on these cells using polychromatic flow cytometry in 20 healthy controls, 20 HIV-monoinfected, 20 HCV-monoinfected and 31 HIV/HCV-co-infected patients. T(reg) cells were defined as CD4(+)forkhead box P3 (FoxP3)(+). The percentage of T(reg) cells was increased significantly in HIV patients compared with controls. Moreover, there was a significant inverse correlation between CD4 counts and T(reg) cell levels. Fewer than 50% of T(reg) cells expressed CD25, with differences in terms of CD127 expression between CD25(+) and CD25((-)) T(reg) cells. CD4(+)Foxp3(+) T(reg) cells displayed predominantly a central memory phenotype (CD45RA(-)CD27(+)), without differences between patients and healthy controls. Activated T(reg) cells were increased in HIV patients, particularly considering the central memory subset. In summary, HIV infection, but not HCV, induces an up-regulation of highly activated T(reg) cells, which increases in parallel with CD4 depletion. Hypothetically, this might contribute to the accelerated course of HCV-related liver disease in HIV-immunosuppressed patients.
Collapse
Affiliation(s)
- N I Rallón
- Department of Infectious Diseases, Hospital Carlos III, 28029 Madrid, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
178
|
Montagnaro S, Longo M, Pacilio M, Indovina P, Roberti A, De Martino L, Iovane G, Pagnini U. Feline herpesvirus-1 down-regulates MHC class I expression in an homologous cell system. J Cell Biochem 2009; 106:179-85. [PMID: 19009565 DOI: 10.1002/jcb.21986] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cytotoxic T lymphocytes (CTLs) are an essential component of the immune defense against many virus infections. CTLs recognize viral peptides in the context of the major histocompatibility complex (MHC) class I molecules on the surface of infected cells. Many viruses have evolved mechanisms to interfere with MHC class I expression as a means of evading the host immune response. In the present research we have studied the effect of in vitro Feline Herpesvirus 1 (FeHV-1) infection on MHC class I expression. The results of this study demonstrate that FeHV-1 down regulates surface expression of MHC class I molecules on infected cells, presumably to evade cytotoxic T-cell recognition and, perhaps, attenuate induction of immunity. Sensitivity to UV irradiation and insensitivity to a viral DNA synthesis inhibitor, like phosphonacetic acid, revealed that immediate early or early viral gene(s) are responsible. Use of the protein translation inhibitor cycloheximide confirmed that an early gene is primarily responsible.
Collapse
Affiliation(s)
- S Montagnaro
- Department of Pathology and animal Health, School of Veterinary Medicine, University of Naples Federico II, Via Delpino no 1, 80137 Naples, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
179
|
Immunobiology of human cytomegalovirus: from bench to bedside. Clin Microbiol Rev 2009; 22:76-98, Table of Contents. [PMID: 19136435 DOI: 10.1128/cmr.00034-08] [Citation(s) in RCA: 468] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SUMMARY Following primary infection, human cytomegalovirus (HCMV) establishes lifelong latency and periodically reactivates without causing symptoms in healthy individuals. In the absence of an adequate host-derived immune response, this fine balance of permitting viral reactivation without causing pathogenesis is disrupted, and HCMV can subsequently cause invasive disease and an array of damaging indirect immunological effects. Over the last decade, our knowledge of the immune response to HCMV infection in healthy virus carriers and diseased individuals has allowed us to translate these findings to develop better diagnostic tools and therapeutic strategies. The application of these emerging technologies in the clinical setting is likely to provide opportunities for better management of patients with HCMV-associated diseases.
Collapse
|
180
|
Schmid-Hempel P. Immune defence, parasite evasion strategies and their relevance for 'macroscopic phenomena' such as virulence. Philos Trans R Soc Lond B Biol Sci 2009; 364:85-98. [PMID: 18930879 DOI: 10.1098/rstb.2008.0157] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The discussion of host-parasite interactions, and of parasite virulence more specifically, has so far, with a few exceptions, not focused much attention on the accumulating evidence that immune evasion by parasites is not only almost universal but also often linked to pathogenesis, i.e. the appearance of virulence. Now, the immune evasion hypothesis offers a deeper insight into the evolution of virulence than previous hypotheses. Sensitivity analysis for parasite fitness and life-history theory shows promise to generate a more general evolutionary theory of virulence by including a major element, immune evasion to prevent parasite clearance from the host. Also, the study of dose-response relationships and multiple infections should be particularly illuminating to understand the evolution of virulence. Taking into account immune evasion brings immunological processes to the core of understanding the evolution of parasite virulence and for a range of related issues such as dose, host specificity or immunopathology. The aim of this review is to highlight the mechanism underlying immune evasion and to discuss possible consequences for the evolutionary ecology analysis of host-parasite interactions.
Collapse
Affiliation(s)
- Paul Schmid-Hempel
- ETH Zürich, Institute of Integrative Biology (IBZ), Universitätsstrasse 16, 8092 Zürich, Switzerland.
| |
Collapse
|
181
|
Miller-Kittrell M, Sparer TE. Feeling manipulated: cytomegalovirus immune manipulation. Virol J 2009; 6:4. [PMID: 19134204 PMCID: PMC2636769 DOI: 10.1186/1743-422x-6-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 01/09/2009] [Indexed: 02/03/2023] Open
Abstract
No one likes to feel like they have been manipulated, but in the case of cytomegalovirus (CMV) immune manipulation, we do not really have much choice. Whether you call it CMV immune modulation, manipulation, or evasion, the bottom line is that CMV alters the immune response in such a way to allow the establishment of latency with lifelong shedding. With millions of years of coevolution within their hosts, CMVs, like other herpesviruses, encode numerous proteins that can broadly influence the magnitude and quality of both innate and adaptive immune responses. These viral proteins include both homologues of host proteins, such as MHC class I or chemokine homologues, and proteins with little similarity to any other known proteins, such as the chemokine binding protein. Although a strong immune response is launched against CMV, these virally encoded proteins can interfere with the host's ability to efficiently recognize and clear virus, while others induce or alter specific immune responses to benefit viral replication or spread within the host. Modulation of host immunity allows survival of both the virus and the host. One way of describing it would be a kind of "mutually assured survival" (as opposed to MAD, Mutually Assured Destruction). Evaluation of this relationship provides important insights into the life cycle of CMV as well as a greater understanding of the complexity of the immune response to pathogens in general.
Collapse
Affiliation(s)
- Mindy Miller-Kittrell
- Department of Microbiology, University of Tennessee, 1414 Cumberland Ave, Knoxville, TN, USA.
| | | |
Collapse
|
182
|
Abstract
Ebola viruses (EBOVs) cause rare but highly fatal outbreaks of viral hemorrhagic fever in humans, and approved treatments for these infections are currently lacking. The Ebola VP35 protein is multifunctional, acting as a component of the viral RNA polymerase complex, a viral assembly factor, and an inhibitor of host interferon (IFN) production. Mutation of select basic residues within the C-terminal half of VP35 abrogates its dsRNA-binding activity, impairs VP35-mediated IFN antagonism, and attenuates EBOV growth in vitro and in vivo. Because VP35 contributes to viral escape from host innate immunity and is required for EBOV virulence, understanding the structural basis for VP35 dsRNA binding, which correlates with suppression of IFN activity, is of high importance. Here, we report the structure of the C-terminal VP35 IFN inhibitory domain (IID) solved to a resolution of 1.4 A and show that VP35 IID forms a unique fold. In the structure, we identify 2 basic residue clusters, one of which is important for dsRNA binding. The dsRNA binding cluster is centered on Arg-312, a highly conserved residue required for IFN inhibition. Mutation of residues within this cluster significantly changes the surface electrostatic potential and diminishes dsRNA binding activity. The high-resolution structure and the identification of the conserved dsRNA binding residue cluster provide opportunities for antiviral therapeutic design. Our results suggest a structure-based model for dsRNA-mediated innate immune antagonism by Ebola VP35 and other similarly constructed viral antagonists.
Collapse
|
183
|
Abstract
Members of the family Iridoviridae infect a diverse array of invertebrate and cold-blooded vertebrate hosts and are currently viewed as emerging pathogens of fish and amphibians. Iridovirid replication is unique and involves both nuclear and cytoplasmic compartments, a circularly permuted, terminally redundant genome that, in the case of vertebrate iridoviruses, is also highly methylated, and the efficient shutoff of host macromolecular synthesis. Although initially neglected largely due to the perceived lack of health, environmental, and economic concerns, members of the genus Ranavirus, and the newly recognized genus Megalocytivirus, are rapidly attracting growing interest due to their involvement in amphibian population declines and their adverse impacts on aquaculture. Herein we describe the molecular and genetic basis of viral replication, pathogenesis, and immunity, and discuss viral ecology with reference to members from each of the invertebrate and vertebrate genera.
Collapse
|
184
|
Abstract
Defending self against nonself is a major problem in a world in which individuals are under constant pressure from parasites that gain fitness benefits at a cost to their host. Defences that have evolved are diverse, and range from behavioural adaptations to physiochemical barriers. The immune defence is a final line of protection and is therefore of great importance. Given this importance, variability in immune defence would seem counterintuitive, yet that is what is observed. Ecological immunology attempts to explain this variation by invoking costs and trade-offs, and in turn proposing that the optimal immune defence will vary over environments. Studies in this field have been highly successful in establishing an evolutionary ecology framework around immunology. However, in order enrich our understanding of this area, it is perhaps time to broaden the focus to include parasites as more than simply elicitors of immune responses. In essence, to view immunity as produced by the host, the environment, and the active involvement of parasites.
Collapse
Affiliation(s)
- Ben M Sadd
- Institute for Integrative Biology (IBZ), Experimental Ecology ETH Zentrum, CHN, Zurich, Switzerland
| | - Paul Schmid-Hempel
- Institute for Integrative Biology (IBZ), Experimental Ecology ETH Zentrum, CHN, Zurich, Switzerland
| |
Collapse
|
185
|
Fairlie-Clarke KJ, Shuker DM, Graham AL. Why do adaptive immune responses cross-react? Evol Appl 2008; 2:122-31. [PMID: 25567852 PMCID: PMC3352416 DOI: 10.1111/j.1752-4571.2008.00052.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 11/06/2008] [Indexed: 11/29/2022] Open
Abstract
Antigen specificity of adaptive immune responses is often in the host's best interests, but with important and as yet unpredictable exceptions. For example, antibodies that bind to multiple flaviviral or malarial species can provide hosts with simultaneous protection against many parasite genotypes. Vaccinology often aims to harness such imprecision, because cross-reactive antibodies might provide broad-spectrum protection in the face of antigenic variation by parasites. However, the causes of cross-reactivity among immune responses are not always known, and here, we explore potential proximate and evolutionary explanations for cross-reactivity. We particularly consider whether cross-reactivity is the result of constraints on the ability of the immune system to process information about the world of antigens, or whether an intermediate level of cross-reactivity may instead represent an evolutionary optimum. We conclude with a series of open questions for future interdisciplinary research, including the suggestion that the evolutionary ecology of information processing might benefit from close examination of immunological data.
Collapse
Affiliation(s)
- Karen J Fairlie-Clarke
- Institutes of Evolution, Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories King's Buildings, Edinburgh, UK
| | - David M Shuker
- Institutes of Evolution, Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories King's Buildings, Edinburgh, UK
| | - Andrea L Graham
- Institutes of Evolution, Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories King's Buildings, Edinburgh, UK
| |
Collapse
|
186
|
Carr DJJ, Austin BA, Halford WP, Stuart PM. Delivery of Interferon-gamma by an adenovirus vector blocks herpes simplex virus Type 1 reactivation in vitro and in vivo independent of RNase L and double-stranded RNA-dependent protein kinase pathways. J Neuroimmunol 2008; 206:39-43. [PMID: 19042034 DOI: 10.1016/j.jneuroim.2008.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 10/20/2008] [Accepted: 10/20/2008] [Indexed: 10/21/2022]
Abstract
HSV-1 is a significant human pathogen that can result in the loss of sight as a result of episodic reactivation of latent virus from sensory ganglion neurons. In this study the potential efficacy of anti-viral cytokine expression in preventing latent virus reactivation was investigated. Both type I (IFN-beta) and type II (IFN-gamma) IFN transgene expression following transduction of trigeminal ganglion explant cultures significantly reduced the incident of HSV-1 reactivation that in the case of IFN-beta was dependent on the presence of double stranded RNA-dependent protein kinase and RNase L. In vivo, expression of the IFN-gamma but not IFN-beta transgene significantly delayed and reduced the frequency of reactivation of latent mice exposed to UV light without discernable inflammation. This result is the first report that demonstrates the ability to block reactivation using an ectopic cytokine expression system and warrants further exploration as a means to prevent HSV-1 reactivation.
Collapse
Affiliation(s)
- Daniel J J Carr
- Department of Ophthalmology, The University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA.
| | | | | | | |
Collapse
|
187
|
Lefebvre D, Meerts P, Costers S, Misinzo G, Barbé F, Van Reeth K, Nauwynck H. Increased porcine circovirus type 2 replication in porcine leukocytes in vitro and in vivo by concanavalin A stimulation. Vet Microbiol 2008; 132:74-86. [DOI: 10.1016/j.vetmic.2008.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 04/23/2008] [Accepted: 05/05/2008] [Indexed: 11/25/2022]
|
188
|
Bonetto S, Spadola L, Buchanan AG, Jermutus L, Lund J. Identification of cyclic peptides able to mimic the functional epitope of IgG1-Fc for human Fc gammaRI. FASEB J 2008; 23:575-85. [PMID: 18957574 PMCID: PMC2633172 DOI: 10.1096/fj.08-117069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Identification of short, structured peptides able to mimic potently protein-protein interfaces remains a challenge in drug discovery. We report here the use of a naive cyclic peptide phage display library to identify peptide ligands able to recognize and mimic IgG1-Fc functions with FcγRI. Selection by competing off binders to FcγRI with IgG1 allowed the isolation of a family of peptides sharing the common consensus sequence TX2CXXθPXLLGCΦXE (θ represents a hydrophobic residue, Φ is usually an acidic residue, and X is any residue) and able to inhibit IgG1 binding to FcγRI. In soluble form, these peptides antagonize superoxide generation mediated by IgG1. In complexed form, they trigger phagocytosis and a superoxide burst. Unlike IgG, these peptides are strictly FcγRI-specific among the FcγRs. Molecular modeling studies suggest that these peptides can adopt 2 distinct and complementary conformers, each able to mimic the discontinuous interface contacts constituted by the Cγ2-A and -B chains of Fc for FcγRI. In addition, by covalent homodimerization, we engineered a synthetic bivalent 37-mer peptide that retains the ability to trigger effector functions. We demonstrate here that it is feasible to maintain IgG-Fc function within a small structured peptide. These peptides represent a new format for modulation of effector functions.—Bonetto, S., Spadola, L., Buchanan, A. G., Jermutus, L. Lund, J. Identification of cyclic peptides able to mimic the functional epitope of IgG1-Fc for human FcγRI.
Collapse
Affiliation(s)
- Stephane Bonetto
- MedImmune, Research, Granta Park, Milstein Bldg., Cambridge, CB21 6GH, UK
| | | | | | | | | |
Collapse
|
189
|
The immune evasion paradox: immunoevasins of murine cytomegalovirus enhance priming of CD8 T cells by preventing negative feedback regulation. J Virol 2008; 82:11637-50. [PMID: 18815306 DOI: 10.1128/jvi.01510-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cytomegaloviruses express glycoproteins that interfere with antigen presentation to CD8 T cells. Although the molecular modes of action of these "immunoevasins" differ between cytomegalovirus species, the convergent biological outcome is an inhibition of the recognition of infected cells. In murine cytomegalovirus, m152/gp40 retains peptide-loaded major histocompatibility complex class I molecules in a cis-Golgi compartment, m06/gp48 mediates their vesicular sorting for lysosomal degradation, and m04/gp34, although not an immunoevasin in its own right, appears to assist in the concerted action of all three molecules. Using the L(d)-restricted IE1 epitope YPHFMPTNL in the BALB/c mouse model as a paradigm, we provide here an explanation for the paradox that immunoevasins enhance CD8 T-cell priming although they inhibit peptide presentation in infected cells. Adaptive immune responses are initiated in the regional lymph node (RLN) draining the site of pathogen exposure. In particular for antigens that are not virion components, the magnitude of viral gene expression providing the antigens is likely a critical parameter in priming efficacy. We have therefore focused on the events in the RLN and have related priming to intranodal viral gene expression. We show that immunoevasins enhance priming by downmodulating an early CD8 T-cell-mediated "negative feedback" control of the infection in the cortical region of the RLN, thus supporting the model that immunoevasins improve antigen supply for indirect priming by uninfected antigen-presenting cells. As an important consequence, these findings predict that deletion of immunoevasin genes in a replicative vaccine virus is not a favorable option but may, rather, be counterproductive.
Collapse
|
190
|
Hammarlund E, Dasgupta A, Pinilla C, Norori P, Früh K, Slifka MK. Monkeypox virus evades antiviral CD4+ and CD8+ T cell responses by suppressing cognate T cell activation. Proc Natl Acad Sci U S A 2008; 105:14567-72. [PMID: 18796610 PMCID: PMC2567221 DOI: 10.1073/pnas.0800589105] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Indexed: 12/17/2022] Open
Abstract
Monkeypox virus (MPV) is a virulent human pathogen that has gained increased attention because of its potential use as a bioterrorism agent and inadvertent introduction into North America in 2003. The US outbreak also provided an important opportunity to study MPV-specific T cell immunity. Although MPV-specific CD4(+) and CD8(+) T cells could recognize vaccinia virus (VV)-infected monocytes and produce inflammatory cytokines such as IFNgamma and TNFalpha, they were largely incapable of responding to autologous MPV-infected cells. Further analysis revealed that, unlike cowpox virus (CPV), MPV did not interfere with MHC expression or intracellular transport of MHC molecules. Instead, MPV-infected cells were capable of preventing T cell receptor (TcR)-mediated T cell activation in trans. The ability to trigger a state of nonresponsiveness represents a unique MHC-independent mechanism for blocking antiviral T cell activation and inflammatory cytokine production and is likely an important attribute involved with viral dissemination in the infected host.
Collapse
Affiliation(s)
- Erika Hammarlund
- *Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 Northwest 185th Avenue, Beaverton, OR 97006; and
| | - Anindya Dasgupta
- *Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 Northwest 185th Avenue, Beaverton, OR 97006; and
| | - Clemencia Pinilla
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
| | - Patricia Norori
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
| | - Klaus Früh
- *Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 Northwest 185th Avenue, Beaverton, OR 97006; and
| | - Mark K. Slifka
- *Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 Northwest 185th Avenue, Beaverton, OR 97006; and
| |
Collapse
|
191
|
Abstract
Chimerism and tolerance in a recipient of a deceased-donor liver transplant. Alexander SI, Smith N, Hu M, Verran D, Shun A, Dorney S, Smith A, Webster B, Shaw PJ, Lammi A, Stormon MO. Complete hematopoietic chimerism and tolerance of a liver allograft from a deceased male donor developed in a 9-year-old girl, with no evidence of graft-versus-host disease 17 months after transplantation. The tolerance was preceded by a period of severe hemolysis, reflecting partial chimerism that was refractory to standard therapies. The hemolysis resolved after the gradual withdrawal of all immunosuppressive therapy.
Collapse
|
192
|
Region between the canine distemper virus M and F genes modulates virulence by controlling fusion protein expression. J Virol 2008; 82:10510-8. [PMID: 18753197 DOI: 10.1128/jvi.01419-08] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Morbilliviruses, including measles and canine distemper virus (CDV), are nonsegmented, negative-stranded RNA viruses that cause severe diseases in humans and animals. The transcriptional units in their genomes are separated by untranslated regions (UTRs), which contain essential transcription and translation signals. Due to its increased length, the region between the matrix (M) protein and fusion (F) protein open reading frames is of particular interest. In measles virus, the entire F 5' region is untranslated, while several start codons are found in most other morbilliviruses, resulting in a long F protein signal peptide (Fsp). To characterize the role of this region in morbillivirus pathogenesis, we constructed recombinant CDVs, in which either the M-F UTR was replaced with that between the nucleocapsid (N) and phosphoprotein (P) genes, or 106 Fsp residues were deleted. The Fsp deletion alone had no effect in vitro and in vivo. In contrast, substitution of the UTR was associated with a slight increase in F gene and protein expression. Animals infected with this virus either recovered completely or experienced prolonged disease and death due to neuroinvasion. The combination of both changes resulted in a virus with strongly increased F gene and protein expression and complete attenuation. Taken together, our results provide evidence that the region between the morbillivirus M and F genes modulates virulence through transcriptional control of the F gene expression.
Collapse
|
193
|
Van Kaer L. Pillars article: antigen presentation: discovery of the peptide TAP. THE JOURNAL OF IMMUNOLOGY 2008; 180:2723-4. [PMID: 18292486 DOI: 10.4049/jimmunol.180.5.2723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Luc Van Kaer
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| |
Collapse
|
194
|
The fetal allograft revisited: does the study of an ancient invertebrate species shed light on the role of natural killer cells at the maternal-fetal interface? Clin Dev Immunol 2008; 2008:631920. [PMID: 18615195 PMCID: PMC2443424 DOI: 10.1155/2008/631920] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 05/12/2008] [Indexed: 12/31/2022]
Abstract
Human pregnancy poses a fundamental immunological problem because the placenta and fetus are genetically different from the host mother. Classical transplantation theory has not provided a plausible solution to this problem. Study of naturally occurring allogeneic chimeras in the colonial marine invertebrate, Botryllus schlosseri, has yielded fresh insight into the primitive development of allorecognition, especially regarding the role of natural killer (NK) cells. Uterine NK cells have a unique phenotype that appears to parallel aspects of the NK-like cells in the allorecognition system of B. schlosseri. Most notably, both cell types recognize and reject "missing self" and both are involved in the generation of a common vascular system between two individuals. Chimeric combination in B. schlosseri results in vascular fusion between two individual colonies; uterine NK cells appear essential to the establishment of adequate maternal-fetal circulation. Since human uterine NK cells appear to de-emphasize primary immunological function, it is proposed that they may share the same evolutionary roots as the B. schlosseri allorecognition system rather than a primary origin in immunity.
Collapse
|
195
|
Kim Y, Park B, Cho S, Shin J, Cho K, Jun Y, Ahn K. Human cytomegalovirus UL18 utilizes US6 for evading the NK and T-cell responses. PLoS Pathog 2008; 4:e1000123. [PMID: 18688275 PMCID: PMC2483941 DOI: 10.1371/journal.ppat.1000123] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 07/11/2008] [Indexed: 11/18/2022] Open
Abstract
Human cytomegalovirus (HCMV) US6 glycoprotein inhibits TAP function, resulting in down-regulation of MHC class I molecules at the cell surface. Cells lacking MHC class I molecules are susceptible to NK cell lysis. HCMV expresses UL18, a MHC class I homolog that functions as a surrogate to prevent host cell lysis. Despite a high level of sequence and structural homology between UL18 and MHC class I molecules, surface expression of MHC class I, but not UL18, is down regulated by US6. Here, we describe a mechanism of action by which HCMV UL18 avoids attack by the self-derived TAP inhibitor US6. UL18 abrogates US6 inhibition of ATP binding by TAP and, thereby, restores TAP-mediated peptide translocation. In addition, UL18 together with US6 interferes with the physical association between MHC class I molecules and TAP that is required for optimal peptide loading. Thus, regardless of the recovery of TAP function, surface expression of MHC class I molecules remains decreased. UL18 represents a unique immune evasion protein that has evolved to evade both the NK and the T cell immune responses. HCMV establishes a lifelong latent infection and causes serious disease in immunocompromised individuals. Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells are the primary effectors for the immune defense against HCMV. However, HCMV has evolved to evade both the innate and adaptive cellular immunity to viral infection. HCMV US6 glycoprotein inhibits TAP function, resulting in down-regulation of MHC class I, while HCMV UL18 is an MHC class I homolog that functions as a surrogate to prevent host cell lysis. Despite significant sequence and structural homology between UL18 and MHC class I molecules, US6 down regulates surface expression of MHC class I, but not UL18. Here, we describe a mechanism by which UL18 circumvents the self-derived TAP inhibitor, US6. UL18 abrogates US6 inhibition of TAP-ATP binding and restores TAP-mediated peptide translocation, thereby making peptides available for the assembly and subsequent surface expression of UL18. Together UL18 and US6 inhibit binding of MHC class I to TAP, thus down regulating surface expression of MHC class I molecules. UL18 represents a unique immune evasion protein resistant to both the NK and T cell immune responses. Our data provide a molecular basis for persistent HCMV infection and will aid in the development of a therapeutic vaccine.
Collapse
Affiliation(s)
- Youngkyun Kim
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Boyoun Park
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Sunglim Cho
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Jinwook Shin
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Kwangmin Cho
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Youngsoo Jun
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Kwangseog Ahn
- National Creative Research Initiatives Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, Korea
- * E-mail:
| |
Collapse
|
196
|
van der Velden AWM, Dougherty JT, Starnbach MN. Down-modulation of TCR expression by Salmonella enterica serovar Typhimurium. THE JOURNAL OF IMMUNOLOGY 2008; 180:5569-74. [PMID: 18390741 DOI: 10.4049/jimmunol.180.8.5569] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
T cell-mediated adaptive immunity is required to help clear infection with the facultative intracellular bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), yet development of T cell-mediated adaptive immunity to S. Typhimurium has been described as slow and inefficient. A key step in inducing T cell-mediated adaptive immunity is T cell priming; the activation, proliferation, and differentiation of naive T cells following initial encounter with Ag. We previously demonstrated that S. Typhimurium had a direct inhibitory effect on naive T cells from mouse, blocking their proliferation. In this study, we show that S. Typhimurium down-modulates expression of the TCR beta-chain, a molecule that is essential for Ag recognition and T cell function. Specifically, we demonstrate that reduced amounts of surface and intracellular TCR-beta protein and decreased levels of tcrbeta transcript are expressed by T cells cultured in the presence of S. Typhimurium. We further show that the down-modulation of TCR-beta expression requires contact between S. Typhimurium and the T cells and that once contact occurs, a factor capable of reducing TCR-beta expression is secreted. These results provide new insight into the mechanism by which S. Typhimurium may inhibit T cell priming and avoid clearance by the adaptive immune system.
Collapse
|
197
|
Chandra V, Kar-Roy A, Kumari S, Mayor S, Jameel S. The hepatitis E virus ORF3 protein modulates epidermal growth factor receptor trafficking, STAT3 translocation, and the acute-phase response. J Virol 2008; 82:7100-10. [PMID: 18448545 PMCID: PMC2446974 DOI: 10.1128/jvi.00403-08] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 04/18/2008] [Indexed: 01/14/2023] Open
Abstract
The hepatitis E virus (HEV) causes acute viral hepatitis, but its characterization is hampered by the lack of an efficient in vitro infection system that can be used to study the effects of HEV proteins on cellular processes. Previous studies suggest that the viral ORF3 protein (pORF3) is essential for infection in vivo and is likely to modulate the host response. Here, we report that pORF3 localizes to early and recycling endosomes and causes a delay in the postinternalization trafficking of epidermal growth factor receptor (EGFR) to late endosomes/lysosomes. The cytoplasmic phosphorylated signal transducer and activator of transcription 3 (pSTAT3) proteins require growth factor receptor endocytosis for their translocation from the cytoplasm to nucleus. Consequently, lower levels of pSTAT3 were found in the nuclei of ORF3-expressing Huh7 human hepatoma cells stimulated with EGF. This results in downregulation of the acute-phase response, a major determinant of inflammation in the host. We propose that through its effects on EGFR trafficking, pORF3 prolongs endomembrane growth factor signaling and promotes cell survival. The effects on STAT3 translocation would result in a reduced inflammatory response. Both of these events are likely to contribute positively to viral replication.
Collapse
Affiliation(s)
- Vivek Chandra
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110 067, India
| | | | | | | | | |
Collapse
|
198
|
CMV infection is associated with the depletion but lack of activation of peripheral blood natural killer cells in a lung transplant cohort. Transpl Immunol 2008; 19:235-7. [DOI: 10.1016/j.trim.2008.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 05/13/2008] [Accepted: 05/23/2008] [Indexed: 11/17/2022]
|
199
|
Oresic K, Tortorella D. Endoplasmic reticulum chaperones participate in human cytomegalovirus US2-mediated degradation of class I major histocompatibility complex molecules. J Gen Virol 2008; 89:1122-1130. [PMID: 18420789 DOI: 10.1099/vir.0.83516-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Inhibition of cell-surface expression of major histocompatibility complex class I molecules by human cytomegalovirus (HCMV, a beta-herpesvirus) promotes escape from recognition by CD8+ cytotoxic T cells. The HCMV US2 and US11 gene products induce class I downregulation during the early phase of HCMV infection by facilitating the degradation of class I heavy chains. The HCMV proteins promote the transport of the class I heavy chains across the endoplasmic reticulum (ER) membrane into the cytosol by a process referred to as 'dislocation', which is then followed by proteasome degradation. This process has striking similarities to the degradation of misfolded ER proteins mediated by ER quality control. Even though the major steps of the dislocation reaction have been characterized, the cellular proteins, specifically the ER chaperones involved in targeting class I for dislocation, have not been fully delineated. To elucidate the chaperones involved in HCMV-mediated class I dislocation, we utilized a chimeric class I heavy chain with an affinity tag at its carboxy terminus. Interestingly, US2 but not US11 continued to target the class I chimera for destruction, suggesting a structural limitation for US11-mediated degradation. Association studies in US2 cells and in cells that express a US2 mutant, US2-186HA, revealed that class I specifically interacts with calnexin, BiP and calreticulin. These findings demonstrate that US2-mediated class I destruction utilizes specific chaperones to facilitate class I dislocation. The data suggest a more general model in which the chaperones that mediate protein folding may also function during ER quality control to eliminate aberrant ER proteins.
Collapse
Affiliation(s)
- Kristina Oresic
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Domenico Tortorella
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
| |
Collapse
|
200
|
Lin PW, Huang YJ, John JAC, Chang YN, Yuan CH, Chen WY, Yeh CH, Shen ST, Lin FP, Tsui WH, Chang CY. Iridovirus Bcl-2 protein inhibits apoptosis in the early stage of viral infection. Apoptosis 2008; 13:165-76. [PMID: 17955372 DOI: 10.1007/s10495-007-0152-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The grouper iridovirus (GIV) belongs to the family Iridoviridae, whose genome contains an antiapoptotic B-cell lymphoma (Bcl)-2-like gene. This study was carried-out to understand whether GIV blocks apoptosis in its host. UV-irradiated grouper kidney (GK) cells underwent apoptosis. However, a DNA fragmentation assay of UV-exposed GK cells after GIV infection revealed an inhibition of apoptosis. The UV- or heat-inactivated GIV failed to inhibit apoptosis, implying that a gene or protein of the viral particle might contribute to an apoptosis inhibitory function. The DNA ladder assay for GIV-infected GK cells after UV irradiation confirmed that apoptosis inhibition was an early process which occurred as early as 5 min post-infection. A GIV-Bcl sequence comparison showed distant sequence similarities to that of human and four viruses; however, all possessed the putative Bcl-2 homology (BH) domains of BH1, BH2, BH3, and BH4, as well as a transmembrane domain. Northern blot hybridization showed that GIV-Bcl transcription began at 2 h post-infection, and the mRNA level significantly increased in the presence of cycloheximide or aphidicolin, indicating that this GIV-Bcl is an immediate-early gene. This was consistent with the Western blot results, which also revealed that the virion carries the Bcl protein. We observed the localization of GIV-Bcl on the mitochondrial membrane and other defined intracellular areas. By immunostaining, it was proven that GIV-Bcl-expressing cells effectively inhibited apoptosis. Taken together, these results demonstrate that GIV inhibits the promotion of apoptosis by GK cells, which is mediated by the immediate early expressed viral Bcl gene.
Collapse
Affiliation(s)
- Pei-Wen Lin
- Molecular Genetics Laboratory, Rm. 336, Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road Section 2, Nankang, Taipei, Taiwan, ROC
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|