scholarly journals Cross-Presentation of Human Cytomegalovirus pp65 (UL83) to CD8+ T Cells Is Regulated by Virus-Induced, Soluble-Mediator-Dependent Maturation of Dendritic Cells

2002 ◽  
Vol 76 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Géraldine Arrode ◽  
Claire Boccaccio ◽  
Jean-Pierre Abastado ◽  
Christian Davrinche
Keyword(s):  
Dendritic Cells ◽  
Human Cytomegalovirus ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Immune Surveillance ◽  
Transforming Growth Factor Β1 ◽  
Cell Mediated Immunity ◽  
Cross Presentation ◽  
Infected Cells ◽  
Dc Maturation

ABSTRACT Cytotoxic CD8+ T lymphocytes (CTL) directed against the matrix protein pp65 are major effectors in controlling infection against human cytomegalovirus (HCMV), a persistent virus of the Betaherpesvirus family. We previously suggested that cross-presentation of pp65 by nonpermissive dendritic cells (DCs) could overcome viral strategies that interfere with activation of CTL (G. Arrode, C. Boccaccio, J. Lule, S. Allart, N. Moinard, J. Abastado, A. Alam, and C. Davrinche, J. Virol. 74:10018–10024, 2000). It is well established that mature DCs are very potent in initiating T-cell-mediated immunity. Consequently, the DC maturation process is a key step targeted by viruses in order to avoid an immune response. Here, we report that immature DCs maintained in coculture with infected human (MRC5) fibroblasts acquired pp65 from early-infected cells for cross-presentation to specific HLA-A2-restricted CTL. In contrast, coculture of DCs in the presence of late-infected cells decreased their capacity to stimulate CTL. Analyses of DC maturation after either coculture with infected MRC5 cells or incubation with infected-cell-conditioned medium revealed that acquisition of a mature phenotype was a prerequisite for efficient stimulation of CTL and that soluble factors secreted by infected cells were responsible for both up and down regulation of CD83 expression on DCs. We identified transforming growth factor β1 secreted by late HCMV-infected cells as one of these down regulating mediators. These findings suggest that HCMV has devised another means to compromise immune surveillance mechanisms. Together, our data indicate that recognition of HCMV-infected cells by DCs has to occur early after infection to avoid immune evasion and to allow generation of anti-HCMV CTL.

scholarly journals Incoming Human Cytomegalovirus pp65 (UL83) Contained in Apoptotic Infected Fibroblasts Is Cross-Presented to CD8+ T Cells by Dendritic Cells

2000 ◽  
Vol 74 (21) ◽  
pp. 10018-10024 ◽  
Author(s):  
Géraldine Arrode ◽  
Claire Boccaccio ◽  
Jacqueline Lulé ◽  
Sophie Allart ◽  
Nathalie Moinard ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Human Cytomegalovirus ◽  
Matrix Protein ◽  
Immune Escape ◽  
Apoptotic Cells ◽  
Necrosis Factor Alpha ◽  
Cross Presentation ◽  
The Matrix ◽  
Antigen Presenting

ABSTRACT Human cytomegalovirus (HCMV) infection is well controlled mainly by cytotoxic CD8+ T lymphocytes (CTL) directed against the matrix protein pp65 despite the numerous immune escape mechanisms developed by the virus. Dendritic cells (DCs) are key antigen-presenting cells for the generation of an immune response which have the capacity to acquire antigens via endocytosis of apoptotic cells and thus present peptides to major histocompatibility complex class I-restricted T cells. We examined whether this mechanism could contribute to the activation of anti-pp65 CTL. In this study, we show that infection by HCMV AD169 induced sensitization of MRC5 fibroblasts to tumor necrosis factor alpha-mediated apoptosis very early after virus inoculation and that pp65 contained in apoptotic cells came from the delivery of the matrix protein into the cell. We observed that immature DCs derived from peripheral monocytes were not permissive to HCMV AD169 infection but were able to internalize pp65-positive apoptotic infected MRC5 cells. We then demonstrated that following exposure to these apoptotic bodies, DCs could activate HLA-A2- or HLA-B35-restricted anti-pp65 CTL, suggesting that they acquired and processed properly fibroblast-derived pp65. Together, our data suggest that cross-presentation of incoming pp65 contained in apoptotic cells may provide a quick and efficient way to prime anti-HCMV CD8+ T cells.

Upregulation of α8β1-integrin in cardiac fibroblast by angiotensin II and transforming growth factor-β1

2001 ◽  
Vol 281 (5) ◽  
pp. C1457-C1467 ◽  
Author(s):  
Gaétan Thibault ◽  
Marie-Josée Lacombe ◽  
Lynn M. Schnapp ◽  
Alexandre Lacasse ◽  
Fatiha Bouzeghrane ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Growth Factor ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β1 ◽  
Cardiac Fibroblast ◽  
Extracellular Matrix Protein ◽  
Ang Ii ◽  
Tgf Β1

Using a novel pharmacological tool with125I-echistatin to detect integrins on the cell, we have observed that cardiac fibroblasts harbor five different RGD-binding integrins: α8β1, α3β1, α5β1, αvβ1, and αvβ3. Stimulation of cardiac fibroblasts by angiotensin II (ANG II) or transforming growth factor-β1 (TGF-β1) resulted in an increase of protein and heightening by 50% of the receptor density of α8β1-integrin. The effect of ANG II was blocked by an AT1, but not an AT2, receptor antagonist, or by an anti-TGF-β1 antibody. ANG II and TGF-β1 increased fibronectin secretion, smooth muscle α-actin synthesis, and formation of actin stress fibers and enhanced attachment of fibroblasts to a fibronectin matrix. The α8- and β1-subunits were colocalized by immunocytochemistry with vinculin or β3-integrin at focal adhesion sites. These results indicate that α8β1-integrin is an abundant integrin on rat cardiac fibroblasts. Its positive modulation by ANG II and TGF-β1 in a myofibroblast-like phenotype suggests the involvement of α8β1-integrin in extracellular matrix protein deposition and cardiac fibroblast adhesion.

scholarly journals Host ER–parasitophorous vacuole interaction provides a route of entry for antigen cross-presentation in Toxoplasma gondii–infected dendritic cells

2009 ◽  
Vol 206 (2) ◽  
pp. 399-410 ◽  
Author(s):  
Romina S. Goldszmid ◽  
Isabelle Coppens ◽  
Avital Lev ◽  
Pat Caspar ◽  
Ira Mellman ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Toxoplasma Gondii ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
Parasitophorous Vacuole ◽  
Host Cells ◽  
Class I ◽  
Cross Presentation ◽  
Infected Cells

Toxoplasma gondii tachyzoites infect host cells by an active invasion process leading to the formation of a specialized compartment, the parasitophorous vacuole (PV). PVs resist fusion with host cell endosomes and lysosomes and are thus distinct from phagosomes. Because the parasite remains sequestered within the PV, it is unclear how T. gondii–derived antigens (Ag’s) access the major histocompatibility complex (MHC) class I pathway for presentation to CD8+ T cells. We demonstrate that recruitment of host endoplasmic reticulum (hER) to the PV in T. gondii–infected dendritic cells (DCs) directly correlates with cross-priming of CD8+ T cells. Furthermore, we document by immunoelectron microscopy the transfer of hER components into the PV, a process indicative of direct fusion between the two compartments. In strong contrast, no association between hER and phagosomes or Ag presentation activity was observed in DCs containing phagocytosed live or dead parasites. Importantly, cross-presentation of parasite-derived Ag in actively infected cells was blocked when hER retrotranslocation was inhibited, indicating that the hER serves as a conduit for the transport of Ag between the PV and host cytosol. Collectively, these findings demonstrate that pathogen-driven hER–PV interaction can serve as an important mechanism for Ag entry into the MHC class I pathway and CD8+ T cell cross-priming.

scholarly journals Dendritic cells require NIK for CD40-dependent cross-priming of CD8+ T cells

2015 ◽  
Vol 112 (47) ◽  
pp. 14664-14669 ◽  
Author(s):  
Anand K. Katakam ◽  
Hans Brightbill ◽  
Christian Franci ◽  
Chung Kung ◽  
Victor Nunez ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Cd8 T Cells ◽  
Lymphoid Organs ◽  
Serine Threonine Kinase ◽  
Cross Presentation ◽  
Inflammatory Stimuli ◽  
Dc Maturation

Dendritic cells (DCs) link innate and adaptive immunity and use a host of innate immune and inflammatory receptors to respond to pathogens and inflammatory stimuli. Although DC maturation via canonical NF-κB signaling is critical for many of these functions, the role of noncanonical NF-κB signaling via the serine/threonine kinase NIK (NF-κB–inducing kinase) remains unclear. Because NIK-deficient mice lack secondary lymphoid organs, we generated transgenic mice with targeted NIK deletion in CD11c+ cells. Although these mice exhibited normal lymphoid organs, they were defective in cross-priming naive CD8+ T cells following vaccination, even in the presence of anti-CD40 or polyinosinic:polycytidylic acid to induce DC maturation. This impairment reflected two intrinsic defects observed in splenic CD8+ DCs in vitro, namely antigen cross-presentation to CD8+ T cells and secretion of IL-12p40, a cytokine known to promote cross-priming in vivo. In contrast, antigen presentation to CD4+ T cells was not affected. These findings reveal that NIK, and thus probably the noncanonical NF-κB pathway, is critical to allow DCs to acquire the capacity to cross-present antigen and prime CD8 T cells after exposure to licensing stimuli, such as an agonistic anti-CD40 antibody or Toll-like receptor 3 ligand.

Rat Achilles tendon healing: mechanical loading and gene expression

2009 ◽  
Vol 107 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Pernilla Eliasson ◽  
Therese Andersson ◽  
Per Aspenberg
Keyword(s):  
Achilles Tendon ◽  
Mechanical Loading ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Lysyl Oxidase ◽  
Late Phase ◽  
Tendon Healing ◽  
Transforming Growth Factor Β1 ◽  
Tenascin C ◽  
Transverse Area

Injured tendons require mechanical tension for optimal healing, but it is unclear which genes are upregulated and responsible for this effect. We unloaded one Achilles tendon in rats by Botox injections in the calf muscles. The tendon was then transected and left to heal. We studied mechanical properties of the tendon calluses, as well as mRNA expression, and compared them with loaded controls. Tendon calluses were studied 3, 8, 14, and 21 days after transection. Intact tendons were studied similarly for comparison. Altogether 110 rats were used. The genes were chosen for proteins marking inflammation, growth, extracellular matrix, and tendon specificity. In intact tendons, procollagen III and tenascin-C were more expressed in loaded than unloaded tendons, but none of the other genes was affected. In healing tendons, loading status had small effects on the selected genes. However, TNF-α transforming growth factor-β1, and procollagens I and III were less expressed in loaded callus tissue at day 3. At day 8 procollagens I and III, lysyl oxidase, and scleraxis had a lower expression in loaded calluses. However, by days 14 and 21, procollagen I, cartilage oligomeric matrix protein, tenascin-C, tenomodulin, and scleraxis were all more expressed in loaded calluses. In healing tendons, the transverse area was larger in loaded samples, but material properties were unaffected, or even impaired. Thus mechanical loading is important for growth of the callus but not its mechanical quality. The main effect of loading during healing might thereby be sought among growth stimulators. In the late phase of healing, tendon-specific genes (scleraxis and tenomodulin) were upregulated with loading, and the healing tissue might to some extent represent a regenerate rather than a scar.

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