Immune evasion proteins of human cytomegalovirus do not prevent a diverse CD8+ cytotoxic T-cell response in natural infection

Blood ◽  
2004 ◽  
Vol 104 (4) ◽  
pp. 1075-1082 ◽  
Author(s):  
Thomas J. Manley ◽  
Lisa Luy ◽  
Thomas Jones ◽  
Michael Boeckh ◽  
Helen Mutimer ◽  
...  

AbstractAlthough cytomegalovirus (CMV) expresses proteins that interfere with antigen presentation by class I major histocompatibility complex (MHC) molecules, CD8+ cytotoxic T cells (CTLs) are indispensable for controlling infection and maintaining latency. Here, a cytokine flow cytometry assay that employs fibroblasts infected with a mutant strain of CMV (RV798), which is deleted of the 4 viral genes that are responsible for interfering with class I MHC presentation, was used to examine the frequency and specificity of the CD8+ CTLs to CMV in immunocompetent CMV-seropositive individuals. A large fraction of the CD8+ CTL response was found to be specific for viral antigens expressed during the immediate early and early phases of virus replication and presented by fibroblasts infected with RV798 but not wild-type CMV. These results demonstrate that the inhibition of class I antigen presentation observed in CMV-infected cells in vitro is not sufficient to prevent the induction of a broad repertoire of CD8+ CTLs after natural infection in vivo. Thus, reconstitution of T-cell immunity in immunodeficient patients by cell therapy or by vaccination may need to target multiple viral antigens to completely restore immunologic control of CMV.

1988 ◽  
Vol 167 (6) ◽  
pp. 1767-1779 ◽  
Author(s):  
F R Carbone ◽  
M W Moore ◽  
J M Sheil ◽  
M J Bevan

Antigen-specific cytotoxic T cells can be generated by primary in vitro stimulation of spleen cells from C57BL/6 mice with appropriate peptide fragments. This response can be elicited without prior in vivo immunization. Chicken OVA fragmented with either cyanogen bromide (CN OVA) or trypsin (T OVA) was used as a source of mixed peptides. A synthetic peptide, NP365-380, representing the sequence 365-380 from influenza virus A/PR/8 nucleoprotein, was also used, since this contains the main determinants recognized by CTL generated from H-2b mice infected with A/PR/8 virus. The primary in vitro cytotoxic T cell response was peptide specific, since targets were lysed only in the presence of appropriate peptide antigens. Native OVA could not elicit primary effectors in vitro nor could it sensitize targets for lysis by OVA digest-specific CTL. A synthetic peptide corresponding to residues 111-122 within the OVA sequence could sensitize targets for lysis by effectors induced against T OVA. Effectors generated by in vitro stimulation were CD8+, CD4-, and H-2Db-restricted for NP365-380 and T OVA recognition. CN OVA-specific effectors were also CD8+, CD4-, but surprisingly, were able to lyse a range of H-2-different targets in an antigen-specific manner. These effectors failed to lyse a tumor line that does not express class I MHC molecules. This broad MHC restriction pattern was also apparent at the clonal level. In all cases, the antipeptide CTL generated by primary in vitro stimulation were inefficient in lysing target cells expressing endogenous forms of antigens, such as influenza virus-infected cells or cells transfected with the OVA cDNA. However, cytotoxic T cell lines generated in vitro against the NP365-380 peptide did contain a minor population of virus-reactive cells that could be selectively expanded by stimulation with A/PR/8-infected spleen cells. These results are discussed in terms of class I-restricted T cell stimulation in the absence of antigen processing by high surface densities of peptide/MHC complexes.


2009 ◽  
Vol 206 (10) ◽  
pp. 2253-2269 ◽  
Author(s):  
Kensuke Takada ◽  
Stephen C. Jameson

Previous studies have suggested that naive CD8 T cells require self-peptide–major histocompatability complex (MHC) complexes for maintenance. However, interpretation of such studies is complicated because of the involvement of lymphopenic animals, as lymphopenia drastically alters naive T cell homeostasis and function. In this study, we explored naive CD8 T cell survival and function in nonlymphopenic conditions by using bone marrow chimeric donors and hosts in which class I MHC expression is absent or limited to radiosensitive versus radioresistant cells. We found that long-term survival of naive CD8 T cells (but not CD4 T cells) was impaired in the absence of class I MHC. However, distinct from this effect, class I MHC deprivation also enhanced naive CD8 T cell responsiveness to low-affinity (but not high-affinity) peptide–MHC ligands. We found that this improved sensitivity was a consequence of up-regulated CD8 levels, which was mediated through a transcriptional mechanism. Hence, our data suggest that, in a nonlymphopenic setting, self-class I MHC molecules support CD8 T cell survival, but that these interactions also attenuate naive T cell sensitivity by dynamic tuning of CD8 levels.


2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Ming Wang ◽  
Yang Cai ◽  
Yong Peng ◽  
Bo Xu ◽  
Wentao Hui ◽  
...  

Abstract Glioblastoma multiforme (GBM) is highly invasive, with a high recurrence rate and limited treatment options, and is the deadliest glioma. Exosomes (Exos) have attracted much attention in the diagnosis and treatment of GBM and are expected to address the severe limitations of biopsy conditions. Exos in the cerebrospinal fluid (CSF) have great potential in GBM dynamic monitoring and intervention strategies. Here, we evaluated the difference in the proteome information of Exos from the CSF (CSF-Exos) between GBM patients and low-grade glioma patients, and the correlations between GBM-CSF-Exos and immunosuppressive properties. Our results indicates that GBM-CSF-Exos contained a unique protein, LGALS9 ligand, which bound to the TIM3 receptor of dendritic cells (DCs) in the CSF to inhibit antigen recognition, processing and presentation by DCs, leading to failure of the cytotoxic T-cell-mediated antitumor immune response. Blocking the secretion of exosomal LGALS9 from GBM tumors could cause mice to exhibit sustained DC tumor antigen-presenting activity and long-lasting antitumor immunity. We concluded that GBM cell-derived exosomal LGALS9 acts as a major regulator of tumor progression by inhibiting DC antigen presentation and cytotoxic T-cell activation in the CSF and that loss of this inhibitory effect can lead to durable systemic antitumor immunity.


PLoS ONE ◽  
2010 ◽  
Vol 5 (8) ◽  
pp. e12120 ◽  
Author(s):  
Alexis Morice ◽  
Béatrice Charreau ◽  
Bérangère Neveu ◽  
Sophie Brouard ◽  
Jean-Paul Soulillou ◽  
...  

1990 ◽  
Vol 171 (5) ◽  
pp. 1815-1820 ◽  
Author(s):  
P Aichele ◽  
H Hengartner ◽  
R M Zinkernagel ◽  
M Schulz

Induction in vivo of antiviral cytotoxic T cell response was achieved in a MHC class I-dependent fashion by immunizing mice three times with a free unmodified 15-mer peptide derived from the nucleoprotein of lymphocytic choriomeningitis virus in IFA. The effector T cells are CD8+, restricted to the class I Ld allele of the analyzed mouse strain, and are specific both at the level of secondary restimulation in vitro and at the effector T cell level. These results suggest that cocktails of viral peptides may be used as antiviral T cell vaccines.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4483-4483
Author(s):  
Marta Gomez-Nunez ◽  
Javier Pinilla-Ibarz ◽  
Tao Dao ◽  
Tatyana Korontsvit ◽  
Victoriya Zakhaleva ◽  
...  

Abstract Major Histocompatibility Complex class I (MHC-I) molecules present antigenic peptides to T cells on the cell surface as a prerequisite for stimulating cytotoxic T cell response. Thus, the ability to reliably identify the peptides that can bind to MHC molecules is of practical importance for rapid vaccine development. Several computer-based prediction methods have been applied to study the interaction of MHC class I/peptide binding. Here we have compared three of the most commonly used predictive algorithms BIMAS, SYFPEITHI and Rankpep with actual binding of HLA-A*0201 peptides in vitro. Forty six HLA-A*0201 peptides were selected from several target oncoproteins: Wilms’ tumor (WT1), native and imatinib- mutated bcr-abl p210 and JAK2 protein. Experimental peptide binding to HLA-A*0201 was assessed using a MHC stabilization assay on T2, TAP deficient cells. Peptides were considered to show positive in vitro binding if the mean fluorescence was at least 50 % of the binding of a high affinity reference peptide. Peptides qualified as positive in vitro if the BIMAS score was ≥ 100, the SYFPEITHI score ranked ≥ 24 or the Rankpep was ≥ 50. Results are summarized below: BIMAS SYFPEITHI RANKPEP Sensitivity 84 % 72 % 60 % Specificity 76 % 71 % 81 % Positive Predictive Value 84 % 72 % 60 % Negative Predictive Value 80 % 68 % 63 % Combining two or more computer methods did not appear to improve the predictive value. In conclusion, of the three predictive algorithms, the best correspondence with the actual MHC binding was demonstrated with the BIMAS algorithm. Predictive computer algorithms are important for preselection of potential T-cell epitope candidates for the application in vaccine design.


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