scholarly journals Escape of Human Cytomegalovirus from HLA-DR-Restricted CD4+ T-Cell Response Is Mediated by Repression of Gamma Interferon-Induced Class II Transactivator Expression

1999 ◽  
Vol 73 (8) ◽  
pp. 6582-6589 ◽  
Author(s):  
Emmanuelle Le Roy ◽  
Annick Mühlethaler-Mottet ◽  
Christian Davrinche ◽  
Bernard Mach ◽  
Jean-Luc Davignon
Keyword(s):  
T Cell ◽  
Human Cytomegalovirus ◽  
Class Ii ◽  
Gamma Interferon ◽  
Immune Recognition ◽  
Viral Inhibition ◽  
Class Ii Transactivator ◽  
Early Protein ◽  
Hla Dr ◽  
Ifn Γ

ABSTRACT Human cytomegalovirus (HCMV), a betaherpesvirus, is a pathogen which escapes immune recognition through various mechanisms. In this paper, we show that HCMV down regulates gamma interferon (IFN-γ)-induced HLA-DR expression in U373 MG astrocytoma cells due to a defect downstream of STAT1 phosphorylation and nuclear translocation. Repression of class II transactivator (CIITA) mRNA expression is detected within the first hours of IFN-γ–HCMV coincubation and results in the absence of HLA-DR synthesis. This defect leads to the absence of presentation of the major immediate-early protein IE1 to specific CD4+ T-cell clones when U373 MG cells, used as antigen-presenting cells, are treated with IFN-γ plus HCMV. However, presentation of endogenously synthesized IE1 can be restored when U373 MG cells are transfected with CIITA prior to infection with HCMV. Altogether, the data indicate that the defect induced by HCMV resides in the activation of the IFN-γ-responsive promoter of CIITA. This is the first demonstration of a viral inhibition of CIITA expression.

Wilms Tumor Protein-1-Derived 9-Mer Peptide Induces CD4 T-Cell Responses in an HLA-DR Restricted Manner

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4351-4351
Author(s):  
Shigeo Fuji ◽  
Julia Fischer ◽  
Markus Kapp ◽  
Thomas G Bumm ◽  
Hermann Einsele ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Class Ii ◽  
Hla Class Ii ◽  
Cd4 T Cell ◽  
Cell Responses ◽  
Hla Dr ◽  
Ifn Γ

Abstract Abstract 4351 Wilms‘ tumor protein-1 (WT1) is one of the most investigated tumor-associated antigens (TAA) in hematological malignancies. CD8 T-cell responses against several WT1-derived peptides have been characterized and are known to contribute to disease control after allogeneic hematopoietic stem cell transplantation (HSCT). Also the identification of human leukocyte antigen (HLA) class II-restricted CD4 T-cell epitopes from WT1 is a challenging task of T-cell-based cancer immunotherapy to improve the effectiveness of WT1 peptide vaccination. We found a highly immunogenic WT1 peptide composed of only 9 amino acids having the ability to induce IFN-γ secretion in CD4 T-cells in an HLA DR-restricted manner. This finding is of great interest as it was generally accepted that HLA class II binding peptides are composed of at least 12 amino acids being recognized by CD4 T-cells, whereas HLA class I binding peptides are composed of 8–11 amino acids being recognized by CD8 T-cells (Wang et al Mol. Immunol. 2002). However, both HLA class I and class II molecules bind to primary and secondary peptide anchor motifs covering the central 9–10 amino acids. Thus, considering this common structural basis for peptide binding there is a possibility that the WT1 9-mer peptide binds to HLA class II molecules, and induces CD4 T-cell responses. IFN-γ induction in response to several WT1 9-mer peptides was screened in 24 HLA-A*02:01 positive patients with acute myeloid leukemia or myelodysplastic syndrome after allogeneic HSCT. Responses to one WT1 9-mer peptide were exclusively detected in CD3+CD4+ T-cells of 2 patients after allogeneic HSCT, but not in CD3+CD4+ T-cells of their corresponding HSC donors. CD4+ T-cell responses to this WT1 9-mer peptide exhibited high levels of functional avidity, as IFN-γ induction was detected after stimulation with 100 ng peptide per mL. Peptide-induced IFN-γ production was confirmed with IFN-γ ELISPOT assays and the HLA restriction of the T-cell response was determined by HLA blocking antibodies. The reaction was significantly blocked by anti-pan HLA class II antibody (85 % reduction), but neither by pan-HLA class I nor by anti-HLA A2 antibody. To identify the subtype of HLA class II molecule, blocking assays with antibodies against HLA-DP, HLA-DR and HLA-DQ were performed. IFN-γ induction was completely abrogated by anti-HLA-DR antibody (99 % reduction) (fig 1, p value of unpaired student‘s t-test <0.0001 for the medium control vs anti-pan HLA class II antibody or anti-HLA-DR antibody, respectively). To test whether IFN-γ was exclusively induced in CD4 T cells, CD4 or CD8 T-cells were depleted from PBMC. Whereas CD8 T-cell depletion did not affect IFN-γ induction, CD4 T-cell depletion completely abrogated the WT1 9-mer peptide induced response (fig 2). CD4 T-cells responding to the WT1 9-mer peptide were indicated to be functional cytotoxic T-cells with an effector CD4 T-cell phenotype. Longitudinal analyses demonstrated the persistence and functionality of WT1 9-mer specific CD4 T-cells in PBMC of patients even at day 1368 after allogeneic HSCT. These data indicate for the first time that a TAA-derived 9-mer peptide can induce HLA class II-restricted CD4 T-cell responses. Vaccination with the characterized WT1 9-mer peptide can enhance the induction and maintenance of not only CD4 but also indirect CD8 T-cell responses. Considering that CD4 T-cells play an important role in tumor rejection, the possibility that other TAA-derived 9-mer peptides having the potential to induce CD4 T-cell responses should be explored in other settings of tumor immunology as well to improve vaccination strategies. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Boosting of DNA Vaccine-Elicited Gamma Interferon Responses in Humans by Exposure to Malaria Parasites

2005 ◽  
Vol 73 (5) ◽  
pp. 2863-2872 ◽  
Author(s):  
Ruobing Wang ◽  
Thomas L. Richie ◽  
Maria Fe Baraceros ◽  
Nancy Rahardjo ◽  
Tanya Gay ◽  
...  
Keyword(s):  
T Cell ◽  
Class Ii ◽  
Gamma Interferon ◽  
Class I ◽  
T Cell Epitopes ◽  
Reduced Frequency ◽  
Negative Effect ◽  
Ifn Γ ◽  
Dna Plasmid ◽  
Macrophage Colony

ABSTRACT A mixture of DNA plasmids expressing five Plasmodium falciparum pre-erythrocyte-stage antigens was administered with or without a DNA plasmid encoding human granulocyte-macrophage colony-stimulating factor (hGM-CSF) as an immune enhancer. After DNA immunization, antigen-specific gamma interferon (IFN-γ) responses were detected by ELISPOT in 15/31 volunteers to multiple class I- and/or class II-restricted T-cell epitopes derived from all five antigens. Responses to multiple epitopes (≤7) were detected simultaneously in some volunteers. By 4 weeks after challenge with P. falciparum parasites, 23/31 volunteers had positive IFN-γ responses and the magnitude of responses was increased from 2- to 143-fold. Nonetheless, none was protected against malaria. Volunteers who received hGM-CSF had a reduced frequency of IFN-γ responses to class I peptides compared to those who only received plasmids expressing P. falciparum proteins before challenge (3/23 versus 3/8; P = 0.15) or after parasite challenge (4/23 versus 5/8; P = 0.015) but not to class II peptides before or after challenge. The responses to one antigen (P. falciparum circumsporozoite protein [PfCSP]) were similar among volunteers who received the five-gene mixture compared to volunteers who only received the PfCSP DNA plasmid in a previous study. In summary, DNA-primed IFN-γ responses were boosted in humans by exposure to native antigen on parasites, coadministration of a plasmid expressing hGM-CSF had a negative effect on boosting of class I-restricted IFN-γ responses, and there was no evidence that immunization with PfCSP DNA in the mixture reduced T-cell responses to PfCSP compared to when it was administered alone.

scholarly journals Human Cytomegalovirus Decreases Major Histocompatibility Complex Class II by Regulating Class II Transactivator Transcript Levels in a Myeloid Cell Line

2020 ◽  
Vol 94 (7) ◽  
Author(s):  
Praneet K. Sandhu ◽  
Nicholas J. Buchkovich
Keyword(s):  
Mhc Class Ii ◽  
Human Cytomegalovirus ◽  
Class Ii ◽  
T Cell Response ◽  
Class Ii Transactivator ◽  
Myeloid Progenitor ◽  
Histocompatibility Complex ◽  
Hla Dr ◽  
Myeloid Progenitor Cell ◽  
Infected Cells

ABSTRACT Human cytomegalovirus (HCMV) is a ubiquitous pathogen that encodes many proteins to modulate the host immune response. Extensive efforts have led to the elucidation of multiple strategies employed by HCMV to effectively block NK cell targeting of virus-infected cells and the major histocompatibility complex (MHC) class I-primed CD8+ T cell response. However, viral regulation of the MHC class II-mediated CD4+ T cell response is understudied in endogenous MHC class II-expressing cells, largely because the popular cell culture systems utilized for studying HCMV do not endogenously express MHC class II. Of the many cell types infected by HCMV in the host, myeloid cells, such as monocytes, are of particular importance due to their role in latency and subsequent dissemination throughout the host. We investigated the impact of HCMV infection on MHC class II in Kasumi-3 cells, a myeloid-progenitor cell line that endogenously expresses the MHC class II gene, HLA-DR. We observed a significant reduction in the expression of surface and total HLA-DR at 72 h postinfection (hpi) and 120 hpi in infected cells. The decrease in HLA-DR expression was independent of the expression of previously described viral genes that regulate the MHC class II complex or the unique short (US) region of HCMV, a region expressing many immunomodulatory genes. The altered surface level of HLA-DR was not a result of increased endocytosis and degradation but was a result of a reduction in HLA-DR transcripts due to a decrease in the expression of the class II transactivator (CIITA). IMPORTANCE Human cytomegalovirus (HCMV) is an opportunistic herpesvirus that is asymptomatic for healthy individuals but that can lead to severe pathology in patients with congenital infections and immunosuppressed patients. Thus, it is important to understand the modulation of the immune response by HCMV, which is understudied in the context of endogenous MHC class II regulation. Using Kasumi-3 cells as a myeloid progenitor cell model endogenously expressing MHC class II (HLA-DR), this study shows that HCMV decreases the expression of HLA-DR in infected cells by reducing the transcription of HLA-DR transcripts early during infection independently of the expression of previously implicated genes. This is an important finding, as it highlights a mechanism of immune evasion utilized by HCMV to decrease the expression of MHC class II in a relevant cell system that endogenously expresses the MHC class II complex.

CD4+ Perforin+ T Cells in B-CLL: MHC Class II Restriction and Anti-Cytomegalovirus Reactivity.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4979-4979
Author(s):  
James Walton ◽  
Keirissa Lawson ◽  
Maria S. Manoussaka ◽  
Amit Nathwani ◽  
Vincent Emory ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Class Ii ◽  
Cd4 Cells ◽  
Hla Dr ◽  
Ifn Γ ◽  
T Cell Expansion

Abstract Introduction: An expansion of CD4+ T cells expressing perforin (PF) has recently been described in B-CLL and we have previously demonstrated anti-cytomegalovirus (CMV) reactivity within this population (Walton et al; 2004; Blood [ASH annual meeting abstracts] 104:4787). Here we further characterise the anti-CMV response of CD4+PF+ T cells in B-CLL and investigate the role of CMV in CD4+PF+ T cell expansion. Methods: Peripheral blood mononuclear cells (PBMC’s) from 24 untreated B-CLL patients (17 CMV seropositive [SP], 7 CMV seronegative [SN]), 2 SP treated (Campath) patients and 12 healthy age-matched control individuals (8 SP, 4 SN) were fixed, permeabilised and stained with anti-CD4PerCP, anti-IFN-γ-APC and anti-PF-FITC monoclonal antibodies (mABs) (BD). PBMC were cultured for 18 hrs with DOWNE cell lysate (Dade Behring) containing CMV-antigen or lysate alone and with anti-CD28 and anti-CD49d mAbs (BD), in the presence of Brefeldin A (eBiosciences). In blocking experiments PBMC were pre-incubated with anti-HLA DR,DP,DQ mAb (BD) for 1 hour. The CMV specific response was assessed by flow cytometry (Dako Cyan, Summit software) as the percentage of IFN-γ+ cells in PF+ and PF− CD4+ T cell populations. Statistical analysis was performed using the Mann-Whitney U test and Spearman rank correlation. Results: The proportion of CD4+ T cells expressing PF directly ex vivo was significantly higher in SP B-CLL patients (17.5±18.6%) compared to SN patients (2.0±2.3%, p=0.019). In seropositive aged matched controls the percentage of CD4+ cells expressing perforin was positively correlated with the percentage of CMV-reactive CD4+ cells (r=0.976, p&lt;0.01). In contrast, there was no significant correlation in the patient group. However, two patients with relatively large expansions of CD4+PF+ cells (37.7±3.39%) post-Campath treatment had high percentages of CMV-reactive CD4+ cells (10.93±0.62%) compared to SP B-CLL patients (1.34±1.19%) and SP controls (1.31±1.14%), implying Campath related CMV reactivation. The addition of anti-HLA-DR,DP,DQ mAb to patients’ PBMCs, prior to CMV stimulation, led to an 80% (from 3.26% to 0.79%) and 90% (from 3.9% to 0.45%) reduction in the proportion of antigen reactive CD4+ and CD4+PF+ cells respectively. Conclusions: A population of major histocompatibility complex (MHC) class II restricted, CMV reactive, CD4+PF+ T cells exists peripherally, in a large group of CMV SP B-CLL patients. Furthermore, CMV is associated with CD4+PF+ T cell expansion in patients and controls. Our data implies that high numbers of B-CLL cells inhibit anti-viral effector function, leading to increased viral activity and chronic antigenic exposure, potentially driving CD4+PF+ T cell expansion.

Human cytomegalovirus protein pp65 mediates accumulation of HLA-DR in lysosomes and destruction of the HLA-DR α-chain

Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 4870-4877 ◽  
Author(s):  
Jenny Odeberg ◽  
Bodo Plachter ◽  
Lars Brandén ◽  
Cecilia Söderberg-Nauclér
Keyword(s):  
Human Cytomegalovirus ◽  
Interferon Γ ◽  
Immune Recognition ◽  
Multiple Strategies ◽  
Hla Dr ◽  
Infected Cells ◽  
Ifn Γ ◽  
Α Chain ◽  
Β Chain ◽  
Hla Class Ii Molecules

AbstractHuman cytomegalovirus (HCMV) has developed multiple strategies to escape immune recognition. Here, we demonstrate that HCMV down-regulates HLA-DR expression in infected interferon γ (IFN-γ)–stimulated fibroblasts at 1 day after infection. Decreased HLA-DR expression was not observed on cells infected with an HCMV strain lacking the pp65 gene (RVAD65), but was observed on cells transfected with the pp65 gene. HLA-DR expression accumulated in vacuoles near the nucleus in HCMV-infected, but not in uninfected or RVAD65-infected cells. In addition, the HLA-DR α-chain, but not the β-chain or HLA-DM, was degraded in HCMV-infected but not in RVAD65-infected cells. Thus, the HCMV protein pp65 mediates decreased expression of HLA-DR, by mediating an accumulation of HLA class II molecules in lysosomes that results in degradation of the HLA-DR α-chain.

scholarly journals Identification and Immune Assessment of T Cell Epitopes in Five Plasmodium falciparum Blood Stage Antigens to Facilitate Vaccine Candidate Selection and Optimization

2021 ◽  
Vol 12 ◽  
Author(s):  
Vinayaka Kotraiah ◽  
Timothy W. Phares ◽  
Frances E. Terry ◽  
Pooja Hindocha ◽  
Sarah E. Silk ◽  
...  
Keyword(s):  
T Cell ◽  
In Silico ◽  
Malaria Vaccine ◽  
Ex Vivo ◽  
Class Ii ◽  
Blood Stage ◽  
Hla Dr ◽  
Ifn Γ ◽  
Blood Stage Malaria

The hurdles to effective blood stage malaria vaccine design include immune evasion tactics used by the parasite such as redundant invasion pathways and antigen variation among circulating parasite strains. While blood stage malaria vaccine development primarily focuses on eliciting optimal humoral responses capable of blocking erythrocyte invasion, clinically-tested Plasmodium falciparum (Pf) vaccines have not elicited sterile protection, in part due to the dramatically high levels of antibody needed. Recent development efforts with non-redundant, conserved blood stage antigens suggest both high antibody titer and rapid antibody binding kinetics are important efficacy factors. Based on the central role of helper CD4 T cells in development of strong, protective immune responses, we systematically analyzed the class II epitope content in five leading Pf blood stage antigens (RH5, CyRPA, RIPR, AMA1 and EBA175) using in silico, in vitro, and ex vivo methodologies. We employed in silico T cell epitope analysis to enable identification of 67 HLA-restricted class II epitope clusters predicted to bind a panel of nine HLA-DRB1 alleles. We assessed a subset of these for HLA-DRB1 allele binding in vitro, to verify the in silico predictions. All clusters assessed (40 clusters represented by 46 peptides) bound at least two HLA-DR alleles in vitro. The overall epitope prediction to in vitro HLA-DRB1 allele binding accuracy was 71%. Utilizing the set of RH5 class II epitope clusters (10 clusters represented by 12 peptides), we assessed stimulation of T cells collected from HLA-matched RH5 vaccinees using an IFN-γ T cell recall assay. All clusters demonstrated positive recall responses, with the highest responses – by percentage of responders and response magnitude – associated with clusters located in the N-terminal region of RH5. Finally, a statistically significant correlation between in silico epitope predictions and ex vivo IFN-γ recall response was found when accounting for HLA-DR matches between the epitope predictions and donor HLA phenotypes. This is the first comprehensive analysis of class II epitope content in RH5, CyRPA, RIPR, AMA1 and EBA175 accompanied by in vitro HLA binding validation for all five proteins and ex vivo T cell response confirmation for RH5.

scholarly journals In the Absence of Endogenous Gamma Interferon, Mice Acutely Infected with Neospora caninum Succumb to a Lethal Immune Response Characterized by Inactivation of Peritoneal Macrophages

2001 ◽  
Vol 8 (4) ◽  
pp. 811-817 ◽  
Author(s):  
Yoshifumi Nishikawa ◽  
Khajornsak Tragoolpua ◽  
Noboru Inoue ◽  
Levi Makala ◽  
Hideyuki Nagasawa ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Mhc Class Ii ◽  
Neospora Caninum ◽  
Acute Infection ◽  
Class Ii ◽  
Peritoneal Macrophages ◽  
Gamma Interferon ◽  
Ifn Γ ◽  
Deficient Mice

ABSTRACT Following infection with Neospora caninum, BALB/c mice were shown to be resistant to an acute infection but developed a latent chronic infection. However, BALB/c background gamma interferon (IFN-γ)-deficient mice were sensitive to the acute infection. Since the immune response in IFN-γ-deficient mice is scantly known, we examined the function of macrophages, major histocompatibility complex (MHC) class II expression, T-cell responses, and serum cytokine levels in the mice. All IFN-γ-deficient mice died within 9 days of infection with N. caninum, whereas those treated with exogenous IFN-γ lived longer. Although N. caninum invaded various organs in both types of mice at the early stage of infection, the parasite was not detected in the brains of resistant hosts until 21 days postinfection (dpi). Peritoneal macrophages from IFN-γ-deficient mice were activated by exogenous IFN-γ associated with inhibition of parasite growth and nitric oxide production as were those from BALB/c mice. IFN-γ-deficient mice failed to increase MHC class II expression on macrophages. Moreover, BALB/c mice induced T-cell proliferation while IFN-γ-deficient mice did not. However, in vivo treatment with exogenous IFN-γ induced up-regulated MHC class II expression in IFN-γ-deficient mice. BALB/c mice treated with an antibody to CD4 showed an increase in morbidity and mortality after parasite infection. In serum, significant levels of IFN-γ and interleukin-4 (IL-4) were detected in resistant hosts, whereas IL-10 was detected in IFN-γ-deficient mice. The levels of IL-12 in IFN-γ-deficient mice were higher than those in BALB/c mice at 7 dpi. The present study indicates that early IFN-γ production has a crucial role in the activation of peritoneal macrophages for the induction of protective immune responses againstN. caninum.

scholarly journals Influenza Virus Vaccination Induces Interleukin-12/23 Receptor β1 (IL-12/23Rβ1)-Independent Production of Gamma Interferon (IFN-γ) and Humoral Immunity in Patients with Genetic Deficiencies in IL-12/23Rβ1 or IFN-γ Receptor I

2008 ◽  
Vol 15 (8) ◽  
pp. 1171-1175 ◽  
Author(s):  
Tjitske de Boer ◽  
Jaap T. van Dissel ◽  
Taco W. J. Kuijpers ◽  
Guus F. Rimmelzwaan ◽  
Frank P. Kroon ◽  
...  
Keyword(s):  
Influenza Virus ◽  
T Cell ◽  
Seasonal Influenza ◽  
Gamma Interferon ◽  
Interleukin 12 ◽  
Virus Vaccination ◽  
Cell Responses ◽  
Antibody Titers ◽  
Ifn Γ ◽  
Striking Contrast

ABSTRACT To investigate whether protective immune responses can be induced in the absence of normal interleukin-12/23/gamma interferon (IL-12/23/IFN-γ) axis signaling, we vaccinated with the seasonal influenza virus subunit vaccine two patients with complete IL-12/23 receptor β1 (IL-12/23Rβ1) deficiencies, two patients with partial IFN-γ receptor I (pIFN-γRI) deficiencies, and five healthy controls. Blood samples were analyzed before, 7 days after, and 28 days after vaccination. In most cases, antibody titers reached protective levels. Moreover, although T-cell responses in patients were lower than those observed in controls, significant influenza virus-specific T-cell proliferation, IFN-γ production, and numbers of IFN-γ-producing cells were found in all patients 7 days after the vaccination. Interestingly, influenza virus-specific IFN-γ responses were IL-12/23 independent, in striking contrast to mycobacterium-induced IFN-γ production. In conclusion, influenza virus vaccination induces IL-12/23-independent IFN-γ production by T cells and can result in sufficient humoral protection in both IL-12/23Rβ1- and pIFN-γRI-deficient individuals.

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