scholarly journals Positive regulation of plasmacytoid dendritic cell function via Ly49Q recognition of class I MHC

2008 ◽  
Vol 205 (13) ◽  
pp. 3187-3199 ◽  
Author(s):  
Lee-Hwa Tai ◽  
Marie-Line Goulet ◽  
Simon Belanger ◽  
Noriko Toyama-Sorimachi ◽  
Nassima Fodil-Cornu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Cell Function ◽  
Viral Infections ◽  
Plasmacytoid Dendritic Cell ◽  
Class I ◽  
Type I ◽  
Class I Mhc ◽  
Mhc Molecules

Plasmacytoid dendritic cells (pDCs) are an important source of type I interferon (IFN) during initial immune responses to viral infections. In mice, pDCs are uniquely characterized by high-level expression of Ly49Q, a C-type lectin-like receptor specific for class I major histocompatibility complex (MHC) molecules. Despite having a cytoplasmic immunoreceptor tyrosine-based inhibitory motif, Ly49Q was found to enhance pDC function in vitro, as pDC cytokine production in response to the Toll-like receptor (TLR) 9 agonist CpG-oligonucleotide (ODN) could be blocked using soluble monoclonal antibody (mAb) to Ly49Q or H-2Kb. Conversely, CpG-ODN–dependent IFN-α production by pDCs was greatly augmented upon receptor cross-linking using immobilized anti-Ly49Q mAb or recombinant H-2Kb ligand. Accordingly, Ly49Q-deficient pDCs displayed a severely reduced capacity to produce cytokines in response to TLR7 and TLR9 stimulation both in vitro and in vivo. Finally, TLR9-dependent antiviral responses were compromised in Ly49Q-null mice infected with mouse cytomegalovirus. Thus, class I MHC recognition by Ly49Q on pDCs is necessary for optimal activation of innate immune responses in vivo.

scholarly journals Structural and Functional Analysis of Human Cytomegalovirus US3 Protein

2004 ◽  
Vol 78 (1) ◽  
pp. 413-423 ◽  
Author(s):  
Shahram Misaghi ◽  
Zhen-Yu J. Sun ◽  
Patrick Stern ◽  
Rachelle Gaudet ◽  
Gerhard Wagner ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Tertiary Structure ◽  
Cytotoxic T Cells ◽  
Protein A ◽  
Class I ◽  
Type I ◽  
Class I Mhc ◽  
Mhc Molecules

ABSTRACT Human cytomegalovirus (HCMV) unique short region 3 (US3) protein, a type I membrane protein, prevents maturation of class I major histocompatibility complex (MHC) molecules by retaining them in the endoplasmic reticulum (ER) and thus helps inhibit antigen presentation to cytotoxic T cells. US3 molecules bind to class I MHC molecules in a transient fashion but retain them very efficiently in the ER nonetheless. The US3 luminal domain is responsible for ER retention of US3 itself, while both the US3 luminal and transmembrane domains are necessary for retaining class I MHC in the ER. We have expressed the luminal domain of US3 molecule in Escherichia coli and analyzed its secondary structure by using nuclear magnetic resonance. We then predicted the US3 tertiary structure by modeling it based on the US2 structure. Unlike the luminal domain of US2, the US3 luminal domain does not obviously interact with class I MHC molecules. The luminal domain of US3 dynamically oligomerizes in vitro and full-length US3 molecules associate with each other in vivo. We present a model depicting how dynamic oligomerization of US3 may enhance its ability to retain class I molecules within the ER.

Imatinib and plasmacytoid dendritic cell function in patients with chronic myeloid leukemia

Blood ◽  
2004 ◽  
Vol 103 (12) ◽  
pp. 4666-4668 ◽  
Author(s):  
Mohamad Mohty ◽  
Eric Jourdan ◽  
Naira Ben Mami ◽  
Norbert Vey ◽  
Ghandi Damaj ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Cell Function ◽  
Plasmacytoid Dendritic Cell ◽  
Molecular Response ◽  
Imatinib Treatment ◽  
Type I ◽  
Immune Functions

Abstract Plasmacytoid dendritic cells (PDCs) are crucial effectors in innate immunity. In this study, we show that imatinib, a potent inhibitor of BCR/ABL tyrosine kinase activity, in the presence of Flt3-Ligand, could induce CD34+ progenitors from chronic myeloid leukemia (CML) to give rise in vitro to typical BDCA-2+ type I interferon-producing PDCs. The effect of imatinib on PDC generation was related to up-regulation of Flt3 on leukemic CD34+ progenitors. Moreover, patients with chronic myeloid leukemia (CML) who were in complete cytogenetic or molecular response after imatinib treatment restored their blood PDCs both quantitatively and functionally comparable to healthy donors, in contrast to patients not responding to imatinib, further confirming that disease response to imatinib is accompanied by restoration of PDC function in vivo. These findings provide evidence that response to imatinib is capable to restore some DC-related immune functions in CML that might be beneficial for long-term disease control. (Blood. 2004;103:4666-4668)

scholarly journals H-2-restricted cytolytic T lymphocytes specific for HLA display T cell receptors of limited diversity.

1992 ◽  
Vol 176 (2) ◽  
pp. 439-447 ◽  
Author(s):  
J L Casanova ◽  
J C Cerottini ◽  
M Matthes ◽  
A Necker ◽  
H Gournier ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptors ◽  
Class I ◽  
Antigenic Peptides ◽  
Class I Mhc ◽  
Cell Receptors ◽  
Mhc Molecules ◽  
Tcr Repertoire

We previously showed that H-2Kd-restricted cytotoxic T lymphocyte (CTL) clones specific for a single nonapeptide derived from the Plasmodium berghei circumsporozoite (PbCS) protein displayed T cell receptors (TCRs) of highly diverse primary structure. We have now analyzed the TCR repertoire of CTLs that recognize a peptide derived from the human class I major histocompatibility complex (MHC) molecule HLA-Cw3 in association with the same murine class I MHC molecule H-2Kd. We first sequenced the TCR alpha and beta genes of the CTL clone Cw3/1.1 and, based on this genomic analysis, the TCR alpha and beta cDNA junctional regions of 23 independent H-2Kd-restricted CTL clones specific for HLA-Cw3. The results show that the TCR chains display very limited heterogeneity, both in terms of V alpha, J alpha, V beta, and J beta segments, and in terms of length and sequence of the CDR3 alpha and beta loops. The TCR repertoire used in vivo was then analyzed by harvesting CTL populations from the peritoneal cavity of immune mice. The peritoneal exudate lymphocytes (PELs) displayed HLA-Cw3-specific cytolytic activity in the absence of any stimulation in vitro. Remarkably, most of these freshly isolated PELs expressed TCRs that shared the same structural features as those from HLA-Cw3-reactive CTL clones. Thus, our results show that a peptide from HLA-Cw3 presented by H-2Kd selects CTLs that bear TCRs of very limited diversity in vivo. When taken together with the high diversity of the TCRs specific for the PbCS peptide, these findings suggest that natural tolerance to self peptides presented by class I MHC molecules may substantially reduce the size of the TCR repertoire of CTLs specific for antigenic peptides homologous to self.

scholarly journals Transcriptional role of p53 in interferon-mediated antiviral immunity

2008 ◽  
Vol 205 (8) ◽  
pp. 1929-1938 ◽  
Author(s):  
César Muñoz-Fontela ◽  
Salvador Macip ◽  
Luis Martínez-Sobrido ◽  
Lauren Brown ◽  
Joseph Ashour ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Viral Replication ◽  
Viral Infections ◽  
Suppressor Gene ◽  
Central Component ◽  
Type I ◽  
Infected Cells

Tumor suppressor p53 is activated by several stimuli, including DNA damage and oncogenic stress. Previous studies (Takaoka, A., S. Hayakawa, H. Yanai, D. Stoiber, H. Negishi, H. Kikuchi, S. Sasaki, K. Imai, T. Shibue, K. Honda, and T. Taniguchi. 2003. Nature. 424:516–523) have shown that p53 is also induced in response to viral infections as a downstream transcriptional target of type I interferon (IFN) signaling. Moreover, many viruses, including SV40, human papillomavirus, Kaposi's sarcoma herpesvirus, adenoviruses, and even RNA viruses such as polioviruses, have evolved mechanisms designated to abrogate p53 responses. We describe a novel p53 function in the activation of the IFN pathway. We observed that infected mouse and human cells with functional p53 exhibited markedly decreased viral replication early after infection. This early inhibition of viral replication was mediated both in vitro and in vivo by a p53-dependent enhancement of IFN signaling, specifically the induction of genes containing IFN-stimulated response elements. Of note, p53 also contributed to an increase in IFN release from infected cells. We established that this p53-dependent enhancement of IFN signaling is dependent to a great extent on the ability of p53 to activate the transcription of IFN regulatory factor 9, a central component of the IFN-stimulated gene factor 3 complex. Our results demonstrate that p53 contributes to innate immunity by enhancing IFN-dependent antiviral activity independent of its functions as a proapoptotic and tumor suppressor gene.

scholarly journals GENETIC CONTROL OF IMMUNE RESPONSES IN VITRO

1974 ◽  
Vol 140 (3) ◽  
pp. 648-659 ◽  
Author(s):  
Judith A. Kapp ◽  
Carl W. Pierce ◽  
Stuart Schlossman ◽  
Baruj Benacerraf
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Immune Responses ◽  
Cell Function ◽  
Suppressor Cells ◽  
Specific Response ◽  
Spleen Cells ◽  
X Irradiation

In recent studies we have found that GAT not only fails to elicit a GAT-specific response in nonresponder mice but also specifically decreases the ability of nonresponder mice to develop a GAT-specific PFC response to a subsequent challenge with GAT bound to the immunogenic carrier, MBSA. Studies presented in this paper demonstrate that B cells from nonresponder, DBA/1 mice rendered unresponsive by GAT in vivo can respond in vitro to GAT-MBSA if exogenous, carrier-primed T cells are added to the cultures. The unresponsiveness was shown to be the result of impaired carrier-specific helper T-cell function in the spleen cells of GAT-primed mice. Spleen cells from GAT-primed mice specifically suppressed the GAT-specific PFC response of spleen cells from normal DBA/1 mice incubated with GAT-MBSA. This suppression was prevented by pretreatment of GAT-primed spleen cells with anti-θ serum plus C or X irradiation. Identification of the suppressor cells as T cells was confirmed by the demonstration that suppressor cells were confined to the fraction of the column-purified lymphocytes which contained θ-positive cells and a few non-Ig-bearing cells. The significance of these data to our understanding of Ir-gene regulation of the immune response is discussed.

scholarly journals STAT2-Dependent Immune Responses Ensure Host Survival despite the Presence of a Potent Viral Antagonist

2018 ◽  
Vol 92 (14) ◽  
Author(s):  
Vu Thuy Khanh Le-Trilling ◽  
Kerstin Wohlgemuth ◽  
Meike U. Rückborn ◽  
Andreja Jagnjic ◽  
Fabienne Maaßen ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Replication ◽  
Mutual Influence ◽  
Type I ◽  
Mcmv Infection ◽  
General Importance ◽  
Interferon Antagonism ◽  
Deficient Mice

ABSTRACTA pathogen encounter induces interferons, which signal via Janus kinases and STAT transcription factors to establish an antiviral state. However, the host and pathogens are situated in a continuous arms race which shapes host evolution toward optimized immune responses and the pathogens toward enhanced immune-evasive properties. Mouse cytomegalovirus (MCMV) counteracts interferon responses by pM27-mediated degradation of STAT2, which directly affects the signaling of type I as well as type III interferons. Using MCMV mutants lackingM27and mice lacking STAT2, we studied the opposing relationship between antiviral activities and viral antagonism in a natural host-pathogen pairin vitroandin vivo. In contrast to wild-type (wt) MCMV, ΔM27 mutant MCMV was efficiently cleared from all organs within a few days in BALB/c, C57BL/6, and 129 mice, highlighting the general importance of STAT2 antagonism for MCMV replication. Despite this effective and relevant STAT2 antagonism, wt and STAT2-deficient mice exhibited fundamentally different susceptibilities to MCMV infections. MCMV replication was increased in all assessed organs (e.g., liver, spleen, lungs, and salivary glands) of STAT2-deficient mice, resulting in mortality during the first week after infection. Taken together, the results of our study reveal the importance of cytomegaloviral interferon antagonism for viral replication as well as a pivotal role of the remaining STAT2 activity for host survival. This mutual influence establishes a stable evolutionary standoff situation with fatal consequences when the equilibrium is disturbed.IMPORTANCEThe host limits viral replication by the use of interferons (IFNs), which signal via STAT proteins. Several viruses evolved antagonists targeting STATs to antagonize IFNs (e.g., cytomegaloviruses, Zika virus, dengue virus, and several paramyxoviruses). We analyzed infections caused by MCMV expressing or lacking the STAT2 antagonist pM27 in STAT2-deficient and control mice to evaluate its importance for the host and the virusin vitroandin vivo. The inability to counteract STAT2 directly translates into exaggerated IFN susceptibilityin vitroand pronounced attenuationin vivo. Thus, the antiviral activity mediated by IFNs via STAT2-dependent signaling drove the development of a potent MCMV-encoded STAT2 antagonist which became indispensable for efficient virus replication and spread to organs required for dissemination. Despite this clear impact of viral STAT2 antagonism, the host critically required the remaining STAT2 activity to prevent overt disease and mortality upon MCMV infection. Our findings highlight a remarkably delicate balance between host and virus.

scholarly journals Targeting mutant p53-expressing tumours with a T cell receptor-like antibody specific for a wild-type antigen

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lionel Low ◽  
Angeline Goh ◽  
Joanna Koh ◽  
Samantha Lim ◽  
Cheng-I Wang
Keyword(s):  
Cell Receptor ◽  
Class I ◽  
Human Antibody ◽  
Mutant P53 ◽  
Wild Type ◽  
Class I Mhc ◽  
Type Antigen ◽  
Wide Range

AbstractAccumulation of mutant p53 proteins is frequently found in a wide range of cancers. While conventional antibodies fail to target intracellular proteins, proteosomal degradation results in the presentation of p53-derived peptides on the tumour cell surface by class I molecules of the major histocompatibility complex (MHC). Elevated levels of such p53-derived peptide-MHCs on tumour cells potentially differentiate them from healthy tissues. Here, we report the engineering of an affinity-matured human antibody, P1C1TM, specific for the unmutated p53125-134 peptide in complex with the HLA-A24 class I MHC molecule. We show that P1C1TM distinguishes between mutant and wild-type p53 expressing HLA-A24+ cells, and mediates antibody dependent cellular cytotoxicity of mutant p53 expressing cells in vitro. Furthermore, we show that cytotoxic PNU-159682-P1C1TM drug conjugates specifically inhibit growth of mutant p53 expressing cells in vitro and in vivo. Hence, p53-associated peptide-MHCs are attractive targets for the immunotherapy against mutant p53 expressing tumours.

scholarly journals Immunotherapy of a murine tumor with interleukin 2. Increased sensitivity after MHC class I gene transfection.

1987 ◽  
Vol 166 (6) ◽  
pp. 1716-1733 ◽  
Author(s):  
J S Weber ◽  
G Jay ◽  
K Tanaka ◽  
S A Rosenberg
Keyword(s):  
T Cells ◽  
Mhc Class I ◽  
Interleukin 2 ◽  
Class I ◽  
High Dose ◽  
Class I Mhc ◽  
High Doses ◽  
I Gene

We have shown that two weakly immunogenic MCA sarcomas developed in our laboratory that are sensitive to high-dose IL-2 immunotherapy express class I MHC in vivo and in vitro. Two nonimmunogenic MCA sarcomas are relatively insensitive to IL-2 therapy and express minimal or no class I MHC molecules in vivo and in vitro. To study the role of MHC in the therapy of tumors with IL-2, a class I-deficient murine melanoma, B16BL6, was transfected with the Kb class I gene. Expression of class I MHC rendered B16BL6 advanced pulmonary macrometastases sensitive to IL-2 immunotherapy. 3-d micrometastases of CL8-2, a class I transfected clone of B16BL6, were significantly more sensitive to IL-2 therapy than a control nontransfected line. Expression of Iak, a class II MHC molecule, had no effect on IL-2 therapy of transfectant pulmonary micrometastases in F1 mice. By using lymphocyte subset depletion with mAbs directed against Lyt-2, therapy of class I transfectant macrometastases with high-dose IL-2 was shown to involve an Lyt-2 cell. In contrast, regression of micrometastases treated with low-dose IL-2 involved Lyt-2+ cells, but regression mediated by high doses of IL-2 did not. We hypothesize that both LAK and Lyt-2+ T cells effect IL-2-mediated elimination of micrometastases, but only Lyt-2+ T cells are involved in macrometastatic regression. Low doses of IL-2 stimulate Lyt-2+ cells to eliminate class I-expressing micrometastases, but high doses of IL-2 can recruit LAK cells to mediate regression of micrometastases independent of class I expression. Only high-dose IL-2, mediating its effect predominantly via Lyt-2+ cells, is capable of impacting on MHC class I-expressing macrometastases. Macrometastases devoid of class I MHC antigens appear to be resistant to IL-2 therapy.

scholarly journals Interferon-Stimulated Gene (ISG)-Expression Screening Reveals the Specific Antibunyaviral Activity of ISG20

2018 ◽  
Vol 92 (13) ◽  
Author(s):  
Junjie Feng ◽  
Arthur Wickenhagen ◽  
Matthew L. Turnbull ◽  
Veronica V. Rezelj ◽  
Felix Kreher ◽  
...  
Keyword(s):  
Viral Infections ◽  
Rhesus Macaques ◽  
Type I ◽  
Emerging Viruses ◽  
Content Type ◽  
Expression Screening ◽  
Interferon Stimulated Genes ◽  
Life Threatening

ABSTRACT Bunyaviruses pose a significant threat to human health, prosperity, and food security. In response to viral infections, interferons (IFNs) upregulate the expression of hundreds of interferon-stimulated genes (ISGs), whose cumulative action can potently inhibit the replication of bunyaviruses. We used a flow cytometry-based method to screen the ability of ∼500 unique ISGs from humans and rhesus macaques to inhibit the replication of Bunyamwera orthobunyavirus (BUNV), the prototype of both the Peribunyaviridae family and the Bunyavirales order. Candidates possessing antibunyaviral activity were further examined using a panel of divergent bunyaviruses. Interestingly, one candidate, ISG20, exhibited potent antibunyaviral activity against most viruses examined from the Peribunyaviridae , Hantaviridae , and Nairoviridae families, whereas phleboviruses ( Phenuiviridae ) largely escaped inhibition. Similar to the case against other viruses known to be targeted by ISG20, the antibunyaviral activity of ISG20 is dependent upon its functional RNase activity. Through use of an infectious virus-like particle (VLP) assay (based on the BUNV minigenome system), we confirmed that gene expression from all 3 viral segments is strongly inhibited by ISG20. Using in vitro evolution, we generated a substantially ISG20-resistant BUNV and mapped the determinants of ISG20 sensitivity/resistance. Taking all the data together, we report that ISG20 is a broad and potent antibunyaviral factor but that some bunyaviruses are remarkably ISG20 resistant. Thus, ISG20 sensitivity/resistance may influence the pathogenesis of bunyaviruses, many of which are emerging viruses of clinical or veterinary significance. IMPORTANCE There are hundreds of bunyaviruses, many of which cause life-threatening acute diseases in humans and livestock. The interferon (IFN) system is a key component of innate immunity, and type I IFNs limit bunyaviral propagation both in vitro and in vivo . Type I IFN signaling results in the upregulation of hundreds of IFN-stimulated genes (ISGs), whose concerted action generates an “antiviral state.” Although IFNs are critical in limiting bunyaviral replication and pathogenesis, much is still unknown about which ISGs inhibit bunyaviruses. Using ISG-expression screening, we examined the ability of ∼500 unique ISGs to inhibit Bunyamwera orthobunyavirus (BUNV), the prototypical bunyavirus. Using this approach, we identified ISG20, an interferon-stimulated exonuclease, as a potent inhibitor of BUNV. Interestingly, ISG20 possesses highly selective antibunyaviral activity, with multiple bunyaviruses being potently inhibited while some largely escape inhibition. We speculate that the ability of some bunyaviruses to escape ISG20 may influence their pathogenesis.

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