scholarly journals Salmonella-Induced Apoptosis of Infected Macrophages Results in Presentation of a Bacteria-Encoded Antigen after Uptake by Bystander Dendritic Cells

2000 ◽  
Vol 191 (4) ◽  
pp. 613-624 ◽  
Author(s):  
Ulf Yrlid ◽  
Mary Jo Wick
Keyword(s):  
Dendritic Cells ◽  
Mhc Class Ii ◽  
Type Iii Secretion ◽  
Apoptosis Induction ◽  
Negative Bacterium ◽  
Wild Type ◽  
Histocompatibility Complex ◽  
Infected Cells ◽  
Induced Apoptosis ◽  
Constitutive Mutant

Salmonella typhimurium is a gram-negative bacterium that survives and replicates inside vacuolar compartments of macrophages. Infection of macrophages with S. typhimurium grown under conditions allowing expression of the type III secretion system results in apoptotic death of the infected cells. Here, we show that infection of bone marrow–derived macrophages (MΦ) with wild-type S. typhimurium 14028 results in presentation of epitopes derived from a bacteria-encoded antigen on major histocompatibility complex (MHC) class I and MHC class II molecules after internalization of apoptotic MΦ by bystander dendritic cells (DCs). In contrast, infection of MΦ with the phoP constitutive mutant strain CS022, which does not induce apoptosis in infected MΦ, does not result in presentation of a bacteria-derived antigen by bystander DCs unless the infected MΦ are induced to undergo apoptosis by treatment with lipopolysaccharide and ATP. DCs appear to be unique in their ability to present antigens derived from MΦ induced to undergo apoptosis by Salmonella, as bystander MΦ are not capable of presenting the bacteria-derived antigen despite the fact that they efficiently internalize the apoptotic cells. These data suggest that apoptosis induction by bacterial infection of MΦ may not be a quiescent death that allows the bacteria to escape recognition by the immune system, but rather may contribute to an antimicrobial immune response upon engulfment by bystander DCs.

scholarly journals Bak and Bax Function To Limit Adenovirus Replication through Apoptosis Induction

2002 ◽  
Vol 76 (9) ◽  
pp. 4547-4558 ◽  
Author(s):  
Andrea Cuconati ◽  
Kurt Degenhardt ◽  
Ramya Sundararajan ◽  
Alan Anschel ◽  
Eileen White
Keyword(s):  
Cellular Level ◽  
Productive Infection ◽  
Apoptosis Induction ◽  
Wild Type ◽  
Caspase 9 ◽  
Proliferation And Apoptosis ◽  
Infected Cells ◽  
Induced Apoptosis ◽  
Induced Changes ◽  
Adenovirus Replication

ABSTRACT Adenovirus infection and expression of E1A induces both proliferation and apoptosis, the latter of which is blocked by the adenovirus Bcl-2 homologue E1B 19K. The mechanism of apoptosis induction and the role that it plays in productive infection are not known. Unlike apoptosis mediated by death receptors, infection with proapoptotic E1B 19K mutant viruses did not induce cleavage of Bid but nonetheless induced changes in Bak and Bax conformation, Bak-Bax interaction, caspase 9 and 3 activation, and apoptosis. In wild-type-adenovirus-infected cells, in which E1B 19K inhibits apoptosis, E1B 19K was bound to Bak, precluding Bak-Bax interaction and changes in Bax conformation. Infection with E1B 19K mutant viruses induced apoptosis in wild-type and Bax- or Bak-deficient baby mouse kidney cells but not in those deficient for both Bax and Bak. Furthermore, Bax and Bak deficiency dramatically increased E1A expression and virus replication. Thus, Bax- and Bak-mediated apoptosis severely limits adenoviral replication, demonstrating that Bax and Bak function as an antiviral response at the cellular level.

scholarly journals Cell Surface Major Histocompatibility Complex Class II Proteins Are Regulated by the Products of the γ134.5 and UL41 Genes of Herpes Simplex Virus 1

2002 ◽  
Vol 76 (14) ◽  
pp. 6974-6986 ◽  
Author(s):  
Joanne Trgovcich ◽  
David Johnson ◽  
Bernard Roizman
Keyword(s):  
Cell Surface ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Histocompatibility Complex ◽  
Virion Host Shutoff ◽  
Virion Host Shutoff Protein ◽  
Infected Cells ◽  
Simplex Virus

ABSTRACT Modulation of host immune responses has emerged as a common strategy employed by herpesviruses both to establish life-long infections and to affect recovery from infection. Herpes simplex virus 1 (HSV-1) blocks the major histocompatibility complex (MHC) class I antigen presentation pathway by inhibiting peptide transport into the endoplasmic reticulum. The interaction of viral gene products with the MHC class II pathway, however, has not been thoroughly investigated, although CD4+ T cells play an important role in human recovery from infection. We have investigated the stability, distribution, and state of MHC class II proteins in glioblastoma cells infected with wild-type HSV-1 or mutants lacking specific genes. We report the following findings. (i) Wild-type virus infection caused a decrease in the accumulation of class II protein on the surface of cells and a decrease in the endocytosis of lucifer yellow or dextran conjugated to fluorescein isothiocyanate but no decrease in the total amount of MHC class II proteins relative to the levels seen in mock-infected cells. (ii) Although the total amount of MHC class II protein remained unchanged, the amounts of cell surface MHC class II proteins were higher in cells infected with the UL41-negative mutant, which lacks the virion host shutoff protein, and especially high in cells infected with the γ134.5-negative mutant. We conclude that infected cells attempt to respond to infection by increased acquisition of antigens and transport of MHC class II proteins to the cell surface and that these responses are blocked in part by the virion host shutoff protein encoded by the UL41 gene and in large measure by the direct or indirect action of the infected cell protein 34.5, the product of the γ134.5 gene.

scholarly journals Retention of adenovirus E19 glycoprotein in the endoplasmic reticulum is essential to its ability to block antigen presentation.

1991 ◽  
Vol 174 (6) ◽  
pp. 1629-1637 ◽  
Author(s):  
J H Cox ◽  
J R Bennink ◽  
J W Yewdell
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Antigen Presentation ◽  
Viral Proteins ◽  
Genetically Engineered ◽  
Class I ◽  
Wild Type ◽  
Histocompatibility Complex ◽  
Infected Cells ◽  
Lumenal Domain

The E3/19K glycoprotein of adenovirus functions to diminish recognition of adenovirus-infected cells by major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTLs) by binding intracellular class I molecules and preventing them from reaching the plasma membrane. In the present study we have characterized the nature of the interaction between E3/19K and the H-2Kd (Kd) molecule. An E3/19K molecule genetically engineered to terminate six residues from its normal COOH terminus (delta E19), was found to associate with Kd in a manner indistinguishable from wild-type E3/19K. Unlike E3/19K, however, delta E19 was transported through the Golgi complex to the plasma membrane, where it could be detected biochemically and immunocytochemically using a monoclonal antibody specific for the lumenal domain of E3/19K. Importantly, delta E19 also differed from E3/19K in being unable to prevent the presentation of Kd-restricted viral proteins to CTLs. This is unlikely to be due to delta E19 having a lower avidity for Kd than E3/19K, since delta E19 was able to compete with E3/19K for Kd binding, both physically, and functionally in nullifying the E3/19K blockade of antigen presentation. These findings indicate that the ability of E3/19K to block antigen presentation is due solely to its ability to retain newly synthesized class I molecules in the endoplasmic reticulum.

scholarly journals CD1 and Major Histocompatibility Complex II Molecules Follow a Different Course during Dendritic Cell Maturation

2003 ◽  
Vol 14 (8) ◽  
pp. 3378-3388 ◽  
Author(s):  
Nicole N. van der Wel ◽  
Masahiko Sugita ◽  
Donna M. Fluitsma ◽  
Xaiochun Cao ◽  
Gerty Schreibelt ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
Dendritic Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Dendritic Cell Maturation ◽  
Cell Maturation ◽  
Major Histocompatibility ◽  
Mhc Molecules ◽  
Histocompatibility Complex

The maturation of dendritic cells is accompanied by the redistribution of major histocompatibility complex (MHC) class II molecules from the lysosomal MHC class II compartment to the plasma membrane to mediate presentation of peptide antigens. Besides MHC molecules, dendritic cells also express CD1 molecules that mediate presentation of lipid antigens. Herein, we show that in human monocyte-derived dendritic cells, unlike MHC class II, the steady-state distribution of lysosomal CD1b and CD1c isoforms was unperturbed in response to lipopolysaccharide-induced maturation. However, the lysosomes in these cells underwent a dramatic reorganization into electron dense tubules with altered lysosomal protein composition. These structures matured into novel and morphologically unique compartments, here termed mature dendritic cell lysosomes (MDL). Furthermore, we show that upon activation mature dendritic cells do not lose their ability of efficient clathrin-mediated endocytosis as demonstrated for CD1b and transferrin receptor molecules. Thus, the constitutive endocytosis of CD1b molecules and the differential sorting of MHC class II from lysosomes separate peptide- and lipid antigen-presenting molecules during dendritic cell maturation.

scholarly journals Inhibition of Heavy Chain and β2-Microglobulin Synthesis as a Mechanism of Major Histocompatibility Complex Class I Downregulation during Epstein-Barr Virus Replication

2006 ◽  
Vol 81 (3) ◽  
pp. 1390-1400 ◽  
Author(s):  
Andre Ortlieb Guerreiro-Cacais ◽  
Mehmet Uzunel ◽  
Jelena Levitskaya ◽  
Victor Levitsky
Keyword(s):  
Mhc Class I ◽  
Mhc Class Ii ◽  
Heavy Chain ◽  
Epstein Barr Virus ◽  
Class I ◽  
Heavy Chains ◽  
Barr Virus ◽  
Histocompatibility Complex ◽  
Infected Cells ◽  
Epstein Barr

ABSTRACT The mechanisms of major histocompatibility complex (MHC) class I downregulation during Epstein-Barr virus (EBV) replication are not well characterized. Here we show that in several cell lines infected with a recombinant EBV strain encoding green fluorescent protein (GFP), the virus lytic cycle coincides with GFP expression, which thus can be used as a marker of virus replication. EBV replication resulted in downregulation of MHC class II and all classical MHC class I alleles independently of viral DNA synthesis or late gene expression. Although assembled MHC class I complexes, the total pool of heavy chains, and β2-microglobulin (β2m) were significantly downregulated, free class I heavy chains were stabilized at the surface of cells replicating EBV. Calnexin expression was increased in GFP+ cells, and calnexin and calreticulin accumulated at the cell surface that could contribute to the stabilization of class I heavy chains. Decreased expression levels of another chaperone, ERp57, and TAP2, a transporter associated with antigen processing and presentation, correlated with delayed kinetics of MHC class I maturation. Levels of both class I heavy chain and β2m mRNA were reduced, and metabolic labeling experiments demonstrated a very low rate of class I heavy chain synthesis in lytically infected cells. MHC class I and MHC class II downregulation was mimicked by pharmacological inhibition of protein synthesis in latently infected cells. Our data suggest that although several mechanisms may contribute to MHC class I downregulation in the course of EBV replication, inhibition of MHC class I synthesis plays the primary role in the process.

Host Plasmacytoid or Conventional Dendritic Cells Alone Are Sufficient To Initiate Graft-Versus-Host Disease.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2164-2164
Author(s):  
Motoko Koyama ◽  
Daigo Hashimoto ◽  
Kazutoshi Aoyama ◽  
Ken-ichi Matsuoka ◽  
Kennosuke Karube ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
B Cells ◽  
Mhc Class Ii ◽  
Graft Versus Host Disease ◽  
Class Ii ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host

Abstract Graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation. Alloantigen expression on host dendritic cells (DCs) is critical to initiate GVHD. DCs can be divided into two main subpopulations; conventional DCs (cDCs) and plasmacytoid DCs (pDCs), however, the contribution of each DC subset to elicit GVHD remains unclear. We examined the ability of cDCs and pDCs to initiate GVHD. pDCs, cDCs and B cells were isolated from C57BL/6 (B6: H–2b) mice treated with Flt3 ligand in order to expand DCs. pDCs were enriched from bone marrow by depleting CD3+, CD19+, CD11b+, and CD49b+ cells, followed by a FACS sorting of CD11cint B220+ cells. cDCs and B cells were sorted from splenocytes as CD11chi B220− cells and CD11c− B220+ cells, respectively. Isolated pDCs showed plasmacytoid morphology, produced IFN-α in response to CpG oligonucleotide. Although pDCs stimulated allogeneic T cells far less potently than cDCs, stimulation with CpG enhanced their allostimulatory capacity as potent as cDCs. We compared the ability of each DC subset to initiate GVHD by an add-back study of MHC class II-expressing DCs into MHC class II-deficient (II−/−) mice that were resistant to CD4-dependent GVHD. Lethally irradiated II−/− B6 mice were injected with 2 × 106 pDCs, cDCs or B cells from wild-type (II+/+) B6 mice on day -1 and injected with 2 × 106 CD4+ T cell from BALB/c (H–2d) mice on day 0. A flow cytometric analysis of the mesenteric lymph nodes on day +5 demonstrated significantly greater expansion of donor CD4+ T cells in recipients of pDCs or cDCs than those of B cells (Table). While injection of B cells did not cause any sign of GVHD, injection of pDCs or cDCs alone was sufficient to produce clinical and pathological GVHD (Table), thus breaking GVHD resistance of II−/− mice. We next examined the ability of pDCs to induce CD8-dependent GVHD in MHC-matched transplant using mice deficient in functional MHC class I expression (β2m−/−). Again, injection of pDCs or cDCs alone was sufficient to cause expansion of donor CD8+ T cells (p<0.05). We next asked whether signaling through Toll-like receptors (TLRs) could be required for pDCs to initiate GVHD. However, injection of pDCs isolated from MyD88/TRIF-double deficient mice was able to initiate GVHD as potent as wild-type pDCs, thus demonstrating that pDCs initiate GVHD in a TLR signaling independent manner. These results provide important information for developing strategies aimed at inactivating host DCs to prevent GVHD. Impact of each APC subpopulation on GVHD APC Donor CD4 expansion (×103±SE) Clinical GVHD score (mean±SE) Pathological GVHD score (mean±SE) *p<0.05 compared with B cells B cell 0.1 ± 0.0 2.1 ± 0.2 2.1 ± 0.2 pDC 5.3 ± 2.4* 4.3 ± 0.3* 7.4 ± 0.5* cDC 9.7 ± 3.8 * 3.8 ± 0.5 * 7.2 ± 0.7*

scholarly journals Major Histocompatibility Complex Class II-Independent Generation of Neutralizing Antibodies against T-Cell-Dependent Borrelia burgdorferi Antigens Presented by Dendritic Cells: Regulation by NK and γδ T Cells

2001 ◽  
Vol 69 (4) ◽  
pp. 2407-2415 ◽  
Author(s):  
M. Lamine Mbow ◽  
Nordin Zeidner ◽  
Robert D. Gilmore ◽  
Marc Dolan ◽  
Joseph Piesman ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
Borrelia Burgdorferi ◽  
Mhc Class Ii ◽  
Γδ T Cells ◽  
Humoral Response ◽  
Class Ii ◽  
Histocompatibility Complex ◽  
Mhc Class Ii Molecules

ABSTRACT We previously showed that adoptive transfer of Borrelia burgdorferi-pulsed dendritic cells (DCs) into syngeneic mice protects animals from challenge with tick-transmitted spirochetes. Here, we demonstrate that the protective immune response is antibody (Ab) dependent and does not require the presence of major histocompatibility complex (MHC) class II molecules on DCs. Mice sensitized with B. burgdorferi-pulsed MHC class II-deficient (MHC class II−/−) DCs mounted a humoral response against protective antigens, includingB. burgdorferi outer surface protein A (OspA) and OspC. B-cell help for the generation of neutralizing anti-OspC immunoglobulin G Abs could be provided by γδ T cells. In contrast, anti-OspA Ab production required the presence of αβ T cells, although this pathway could be independent of MHC class II molecules on antigen-presenting cells. Moreover, depletion of NK cells prior to transfer of antigen-pulsed MHC class II−/− DCs resulted in significant increases in the levels of neutralizing Abs induced by DCs. Altogether, these data suggest that the initial interactions between DCs and innate immune cells, such as γδ and NK cells, can influence the generation of a protective humoral response againstB. burgdorferi antigens.

scholarly journals Rescue of thymocytes from glucocorticoid-induced cell death mediated by CD28/CTLA-4 costimulatory interactions with B7-1/B7-2.

1996 ◽  
Vol 184 (5) ◽  
pp. 1631-1638 ◽  
Author(s):  
D H Wagner ◽  
J Hagman ◽  
P S Linsley ◽  
W Hodsdon ◽  
J H Freed ◽  
...  
Keyword(s):  
Cell Death ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
T Cell Receptors ◽  
Negative Selection ◽  
Potential Mechanism ◽  
Transfected Cells ◽  
Histocompatibility Complex ◽  
Thymocyte Apoptosis ◽  
Induced Apoptosis

During the differentiation of thymocytes to mature T cells the processes of positive and negative selection result in signals that either protect thymocytes from cell death, or delete, through apoptosis, thymocytes with self-reactive T cell receptors (TCR). Glucocorticoids have been shown to induce thymocyte apoptosis and are produced within the thymic microenvironment. Furthermore, steroid-induced apoptosis of thymocytes has been suggested as a potential mechanism for removal of nonselected thymocytes. In this report, we demonstrate that thymocytes can be rescued from glucocorticoid-induced apoptosis by incubation with cells that express high levels of B7-1 or B7-2. In addition, the ability to be rescued by B7-1 and/or B7-2 can precede expression of the TCR. We demonstrate that CD3(+)-depleted or CD3+/ TCR-beta(+)-doubly depleted thymocytes can be rescued from glucocorticoid-induced apoptosis through the interaction of CD28 or CTLA-4 on thymocytes with cells bearing high levels of B7-1 or B7-2. Furthermore, these transfected cells are major histocompatibility complex (MHC) class II negative and, while they may express MHC class I, there is no preferential rescue of CD8+ thymocytes in the presence of glucocorticoids. Together, these data suggest that the rescue of thymocytes from glucocorticoids can be independent of the TCR. We also demonstrate that, in addition to CD28, CTLA-4 is expressed on thymocytes, suggesting that rescue from glucocorticoid-induced cell death can be mediated by both CD28 and CTLA-4. A CTLA-4Ig fusion protein which binds to both B7-1 and B7-2 was shown to completely block the rescue of thymocytes from glucocorticoid-induced cell death. Therefore, we conclude that interactions between B7-1/B7-2 and CD28/CTLA-4 are sufficient and necessary for rescue of thymocytes from glucocorticoid-induced cell death.

scholarly journals Efficient Presentation of Phagocytosed Cellular Fragments on the Major Histocompatibility Complex Class II Products of Dendritic Cells

1998 ◽  
Vol 188 (11) ◽  
pp. 2163-2173 ◽  
Author(s):  
Kayo Inaba ◽  
Shannon Turley ◽  
Fumiya Yamaide ◽  
Tomonori Iyoda ◽  
Karsten Mahnke ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
Lymph Node ◽  
B Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Histocompatibility Complex ◽  
Antigen Transfer ◽  
Cell Fragments

Cells from the bone marrow can present peptides that are derived from tumors, transplants, and self-tissues. Here we describe how dendritic cells (DCs) process phagocytosed cell fragments onto major histocompatibility complex (MHC) class II products with unusual efficacy. This was monitored with the Y-Ae monoclonal antibody that is specific for complexes of I-Ab MHC class II presenting a peptide derived from I-Eα. When immature DCs from I-Ab mice were cultured for 5–20 h with activated I-E+ B blasts, either necrotic or apoptotic, the DCs produced the epitope recognized by the Y-Ae monoclonal antibody and stimulated T cells reactive with the same MHC–peptide complex. Antigen transfer was also observed with human cells, where human histocompatibility leukocyte antigen (HLA)-DRα includes the same peptide sequence as mouse I-Eα. Antigen transfer was preceded by uptake of B cell fragments into MHC class II–rich compartments. Quantitation of the amount of I-E protein in the B cell fragments revealed that phagocytosed I-E was 1–10 thousand times more efficient in generating MHC–peptide complexes than preprocessed I-E peptide. When we injected different I-E– bearing cells into C57BL/6 mice to look for a similar phenomenon in vivo, we found that short-lived migrating DCs could be processed by most of the recipient DCs in the lymph node. The consequence of antigen transfer from migratory DCs to lymph node DCs is not yet known, but we suggest that in the steady state, i.e., in the absence of stimuli for DC maturation, this transfer leads to peripheral tolerance of the T cell repertoire to self.

scholarly journals The protein tyrosine kinase p56lck regulates cell adhesion mediated by CD4 and major histocompatibility complex class II proteins.

1994 ◽  
Vol 180 (5) ◽  
pp. 1729-1739 ◽  
Author(s):  
M S Kinch ◽  
A Sanfridson ◽  
C Doyle
Keyword(s):  
Cell Adhesion ◽  
B Cells ◽  
Tyrosine Kinase ◽  
Mhc Class Ii ◽  
Kinase Activity ◽  
Class Ii ◽  
Wild Type ◽  
Tyrosine Kinase Activity ◽  
Histocompatibility Complex ◽  
Mhc Class Ii Molecules

The CD4 protein is expressed on a subset of human T lymphocytes that recognize antigen in the context of major histocompatibility complex (MHC) class II molecules. Using Chinese hamster ovary (CHO) cells expressing human CD4, we have previously demonstrated that the CD4 protein can mediate cell adhesion by direct interaction with MHC class II molecules. In T lymphocytes, CD4 can also function as a signaling molecule, presumably through its intracellular association with p56lck, a member of the src family of protein tyrosine kinases. In the present report, we show that p56lck can affect cell adhesion mediated by CD4 and MHC class II molecules. The expression of wild-type p56lck in CHO-CD4 cells augments the binding of MHC class II+ B cells, whereas the expression of a mutant p56lck protein with elevated tyrosine kinase activity results in decreased binding of MHC class II+ B cells. Using site-specific mutants of p56lck, we demonstrate that the both the enzymatic activity of p56lck and its association with CD4 are required for this effect on CD4/MHC class II adhesion. Further, the binding of MHC class II+ B cells induces CD4 at the cell surface to become organized into structures resembling adhesions-type junctions. Both wild-type and mutant forms of p56lck influence CD4-mediated adhesion by regulating the formation of these structures. The wild-type lck protein enhances CD4/MHC class II adhesion by augmenting the formation of CD4-associated adherens junctions whereas the elevated tyrosine kinase activity of the mutant p56lck decreases CD4-mediated cell adhesion by preventing the formation of these structures.

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