scholarly journals An immunodominance hierarchy exists in CD8+ T cell responses to HLA-A*02:01-restricted epitopes identified from the non-structural polyprotein 1a of SARS-CoV-2

2020 ◽  
Author(s):  
Akira Takagi ◽  
Masanori Matsui
Keyword(s):  
T Lymphocytes ◽  
Transgenic Mice ◽  
Cytotoxic T Lymphocytes ◽  
Intracellular Cytokine Staining ◽  
Reaction Pattern ◽  
Binding Affinities ◽  
Intracellular Cytokine ◽  
Ctl Epitopes ◽  
Selection For ◽  
Epitope Selection

AbstractCOVID-19 vaccines are being rapidly developed and human trials are underway. Almost all of these vaccines have been designed to induce antibodies targeting spike protein of SARS-CoV-2 in expectation of neutralizing activities. However, non-neutralizing antibodies are at risk of causing antibody-dependent enhancement. Further, the longevity of SARS-CoV-2-specific antibodies is very short. Therefore, in addition to antibody-induced vaccines, novel vaccines on the basis of SARS-CoV-2-specific cytotoxic T lymphocytes (CTLs) should be considered in the vaccine development. Here, we attempted to identify HLA-A*02:01-restricted CTL epitopes derived from the non-structural polyprotein 1a of SARS-CoV-2. Eighty-two peptides were firstly predicted as epitope candidates on bioinformatics. Fifty-four in 82 peptides showed high or medium binding affinities to HLA-A*02:01. HLA-A*02:01 transgenic mice were then immunized with each of the 54 peptides encapsulated into liposomes. The intracellular cytokine staining assay revealed that 18 out of 54 peptides were CTL epitopes because of the induction of IFN-γ-producing CD8+ T cells. In the 18 peptides, 10 peptides were chosen for the following analyses because of their high responses. To identify dominant CTL epitopes, mice were immunized with liposomes containing the mixture of the 10 peptides. Some peptides were shown to be statistically predominant over the other peptides. Surprisingly, all mice immunized with the liposomal 10 peptide mixture did not show the same reaction pattern to the 10 peptides. There were three pattern types that varied sequentially, suggesting the existence of an immunodominance hierarchy, which may provide us more variations in the epitope selection for designing CTL-based COVID-19 vaccines.ImportanceFor the development of vaccines based on SARS-CoV-2-specific cytotoxic T lymphocytes (CTLs), we attempted to identify HLA-A*02:01-restricted CTL epitopes derived from the non-structural polyprotein 1a of SARS-CoV-2. Out of 82 peptides predicted on bioinformatics, 54 peptides showed good binding affinities to HLA-A*02:01. Using HLA-A*02:01 transgenic mice, 18 in 54 peptides were found to be CTL epitopes in the intracellular cytokine staining assay. Out of 18 peptides, 10 peptides were chosen for the following analyses because of their high responses. To identify dominant epitopes, mice were immunized with liposomes containing the mixture of the 10 peptides. Some peptides were shown to be statistically predominant. Surprisingly, all immunized mice did not show the same reaction pattern to the 10 peptides. There were three pattern types that varied sequentially, suggesting the existence of an immunodominance hierarchy, which may provide us more variations in the epitope selection for designing CTL-based COVID-19 vaccines.

scholarly journals Identification of HLA-A*02:01-restricted candidate epitopes derived from the non-structural polyprotein 1a of SARS-CoV-2 that may be natural targets of CD8+ T cell recognition in vivo

2020 ◽  
Author(s):  
Akira Takagi ◽  
Masanori Matsui
Keyword(s):  
T Lymphocytes ◽  
Transgenic Mice ◽  
Cytotoxic T Lymphocytes ◽  
Intracellular Cytokine Staining ◽  
Binding Affinities ◽  
Intracellular Cytokine ◽  
Peptide Vaccination ◽  
Ctl Epitopes ◽  
Selection For ◽  
Epitope Selection

COVID-19 vaccines are being rapidly developed and human trials are underway. Almost all of these vaccines have been designed to induce antibodies targeting spike protein of SARS-CoV-2 in expectation of neutralizing activities. However, non-neutralizing antibodies are at risk of causing antibody-dependent enhancement. Further, the longevity of SARS-CoV-2-specific antibodies is very short. Therefore, in addition to antibody-induced vaccines, novel vaccines on the basis of SARS-CoV-2-specific cytotoxic T lymphocytes (CTLs) should be considered in the vaccine development. Here, we attempted to identify HLA-A*02:01-restricted CTL epitopes derived from the non-structural polyprotein 1a of SARS-CoV-2. Eighty-two peptides were firstly predicted as epitope candidates on bioinformatics. Fifty-four in 82 peptides showed high or medium binding affinities to HLA-A*02:01. HLA-A*02:01 transgenic mice were then immunized with each of the 54 peptides encapsulated into liposomes. The intracellular cytokine staining assay revealed that 18 out of 54 peptides were CTL epitopes because of the induction of IFN-γ-producing CD8+ T cells. In the 18 peptides, 10 peptides were chosen for the following analyses because of their high responses. To identify dominant CTL epitopes, mice were immunized with liposomes containing the mixture of the 10 peptides. Some peptides were shown to be statistically predominant over the other peptides. Surprisingly, all mice immunized with the liposomal 10 peptide mixture did not show the same reaction pattern to the 10 peptides. There were three response patterns, suggesting the existence of an immunodominance hierarchy following peptide vaccination, which may provide us more variations in the epitope selection for designing CTL-based COVID-19 vaccines. IMPORTANCE For the development of vaccines based on SARS-CoV-2-specific cytotoxic T lymphocytes (CTLs), we attempted to identify HLA-A*02:01-restricted CTL epitopes derived from the non-structural polyprotein 1a of SARS-CoV-2. Out of 82 peptides predicted on bioinformatics, 54 peptides showed good binding affinities to HLA-A*02:01. Using HLA-A*02:01 transgenic mice, 18 in 54 peptides were found to be CTL epitopes in the intracellular cytokine staining assay. Out of 18 peptides, 10 peptides were chosen for the following analyses because of their high responses. To identify dominant epitopes, mice were immunized with liposomes containing the mixture of the 10 peptides. Some peptides were shown to be statistically predominant. Surprisingly, all immunized mice did not show the same reaction pattern to the 10 peptides. There were three reaction patterns, suggesting the existence of an immunodominance hierarchy following peptide vaccination, which may provide us more variations in the epitope selection for designing CTL-based COVID-19 vaccines.

scholarly journals Functionally Inert HIV-Specific Cytotoxic T Lymphocytes Do Not Play a Major Role in Chronically Infected Adults and Children

2000 ◽  
Vol 192 (12) ◽  
pp. 1819-1832 ◽  
Author(s):  
Philip J.R. Goulder ◽  
Yanhua Tang ◽  
Christian Brander ◽  
Michael R. Betts ◽  
Marcus Altfeld ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Hiv Infection ◽  
Cytotoxic T Lymphocytes ◽  
Intracellular Cytokine Staining ◽  
Cell Number ◽  
Lymphocytic Choriomeningitis ◽  
Intracellular Cytokine ◽  
Virus Infections ◽  
Tetramer Binding ◽  
Ifn Γ

The highly sensitive quantitation of virus-specific CD8+ T cells using major histocompatibility complex–peptide tetramer assays has revealed higher levels of cytotoxic T lymphocytes (CTLs) in acute and chronic virus infections than were recognized previously. However, studies in lymphocytic choriomeningitis virus infection have shown that tetramer assays may include measurement of a substantial number of tetramer-binding cells that are functionally inert. Such phenotypically silent CTLs, which lack cytolytic function and do not produce interferon (IFN)-γ, have been hypothesized to explain the persistence of virus in the face of a quantitatively large immune response, particularly when CD4 help is impaired. In this study, we examined the role of functionally inert CTLs in chronic HIV infection. Subjects studied included children and adults (n = 42) whose viral loads ranged from <50 to >100,000 RNA copies/ml plasma. Tetramer assays were compared with three functional assays: enzyme-linked immunospot (Elispot), intracellular cytokine staining, and precursor frequency (limiting dilution assay [LDA]) cytotoxicity assays. Strong positive associations were observed between cell numbers derived by the Elispot and the tetramer assay (r = 0.90). An even stronger association between tetramer-derived numbers and intracellular cytokine staining for IFN-γ was present (r = 0.97). The majority (median 76%) of tetramer-binding cells were consistently detectable via intracellular IFN-γ cytokine staining. Furthermore, modifications to the LDA, using a low input cell number into each well, enabled LDAs to reach equivalence with the other methods of CTL enumeration. These data together show that functionally inert CTLs do not play a significant role in chronic pediatric or adult HIV infection.

scholarly journals Transgenic Mice Expressing Human HLA and CD8 Molecules Generate HLA-Restricted Measles Virus Cytotoxic T Lymphocytes of the Same Specificity as Humans with Natural Measles Virus Infection

Virology ◽  
2000 ◽  
Vol 275 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Antoinette Tishon ◽  
Drake M. LaFace ◽  
Hanna Lewicki ◽  
Robert S. van Binnendijk ◽  
Albert Osterhaus ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Virus Infection ◽  
Transgenic Mice ◽  
Cytotoxic T Lymphocytes ◽  
Measles Virus

Transfer of HIV-1-specific cytotoxic T lymphocytes to an AIDS patient leads to selection for mutant HIV variants and subsequent disease progression

1995 ◽  
Vol 1 (4) ◽  
pp. 330-336 ◽  
Author(s):  
Scott Koenig ◽  
Anthony J. Conley ◽  
Yambasu A. Brewah ◽  
Gary M. Jones ◽  
Simon Leath ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Disease Progression ◽  
Cytotoxic T Lymphocytes ◽  
Selection For ◽  
Hiv 1

scholarly journals The Hypervariable Immunodominant NP418-426 Epitope from the Influenza A Virus Nucleoprotein Is Recognized by Cytotoxic T Lymphocytes with High Functional Avidity

2006 ◽  
Vol 80 (12) ◽  
pp. 6024-6032 ◽  
Author(s):  
Adrianus C. M. Boon ◽  
Gerrie de Mutsert ◽  
Ron A. M. Fouchier ◽  
Albert D. M. E. Osterhaus ◽  
Guus F. Rimmelzwaan
Keyword(s):  
T Lymphocytes ◽  
Influenza A Virus ◽  
Cytotoxic T Lymphocytes ◽  
Influenza A ◽  
Mononuclear Cells ◽  
Influenza Viruses ◽  
Functional Avidity ◽  
Human Virus ◽  
Ctl Epitopes ◽  
Infected Cells

ABSTRACT Recently it was shown that influenza A viruses can accumulate mutations in epitopes associated with escape from recognition by human virus-specific cytotoxic T lymphocytes (CTL). It is unclear what drives diversification of CTL epitopes and why certain epitopes are variable and others remain conserved. It has been shown that simian immunodeficiency virus-specific CTL that recognize their epitope with high functional avidity eliminate virus-infected cells efficiently and drive diversification of CTL epitopes. T-cell functional avidity is defined by the density of major histocompatibility complex class I peptide complexes required to activate specific CTL. We hypothesized that functional avidity of CTL contributes to epitope diversification and escape from CTL also for influenza viruses. To test this hypothesis, the functional avidity of polyclonal CTL populations specific for nine individual epitopes was determined. To this end, peripheral blood mononuclear cells from HLA-A- and -B-genotyped individuals were stimulated in vitro with influenza virus-infected cells to allow expansion of virus-specific CTL, which were used to determine the functional avidity of CTL specific for nine individual epitopes in enzyme-linked immunospot assays. We found that the functional avidity for the respective epitopes varied widely. Furthermore, the functional avidity of CTL specific for the hypervariable NP418-426 epitope was significantly higher than that of CTL recognizing other epitopes (P < 0.01). It was speculated that the high functional avidity of NP418-426-specific CTL was responsible for the diversification of this influenza A virus CTL epitope.

scholarly journals Synthetic peptides coupled to the surface of liposomes effectively induce SARS coronavirus-specific cytotoxic T lymphocytes and viral clearance in HLA-A*0201 transgenic mice

Vaccine ◽  
2009 ◽  
Vol 27 (29) ◽  
pp. 3912-3920 ◽  
Author(s):  
Satoshi Ohno ◽  
Shunsuke Kohyama ◽  
Maiko Taneichi ◽  
Osamu Moriya ◽  
Hidenori Hayashi ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Transgenic Mice ◽  
Cytotoxic T Lymphocytes ◽  
Synthetic Peptides ◽  
Viral Clearance ◽  
Sars Coronavirus

scholarly journals Gag Protein Epitopes Recognized by ELA-A-Restricted Cytotoxic T Lymphocytes from Horses with Long-Term Equine Infectious Anemia Virus Infection

1998 ◽  
Vol 72 (12) ◽  
pp. 9612-9620 ◽  
Author(s):  
Wei Zhang ◽  
Scott M. Lonning ◽  
Travis C. McGuire
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Equine Infectious Anemia Virus ◽  
Class I ◽  
Target Cells ◽  
Ctl Epitopes ◽  
Peptide Epitopes ◽  
Equine Infectious Anemia ◽  
Anemia Virus

ABSTRACT Most equine infectious anemia virus (EIAV)-infected horses have acute clinical disease, but they eventually control the disease and become lifelong carriers. Cytotoxic T lymphocytes (CTL) are considered an important immune component in the control of infections with lentiviruses including EIAV, but definitive evidence for CTL in the control of disease in carrier horses is lacking. By using retroviral vector-transduced target cells expressing different Gag proteins and overlapping synthetic peptides of 16 to 25 amino acids, peptides containing at least 12 Gag CTL epitopes recognized by virus-stimulated PBMC from six long-term EIAV-infected horses were identified. All identified peptides were located within Gag matrix (p15) and capsid (p26) proteins, as no killing of target cells expressing p11 and p9 occurred. Each of the six horses had CTL recognizing at least one Gag epitope, while CTL from one horse recognized at least eight different Gag epitopes. None of the identified peptides were recognized by CTL from all six horses. Two nonamer peptide epitopes were defined from Gag p26; one (18a) was likely restricted by class I equine leukocyte alloantigen A5.1 (ELA-A5.1) molecules, and the other (28b-1) was likely restricted by ELA-A9 molecules. Sensitization of equine kidney target cells for CTLm killing required 10 nM peptide 18a and 1 nM 28b-1. The results demonstrated that diverse CTL responses against Gag epitopes were generated in long-term EIAV-infected horses and indicated that ELA-A class I molecules were responsible for the diversity of CTL epitopes recognized. This information indicates that multiple epitopes or whole proteins will be needed to induce CTL in horses with different ELA-A alleles in order to evaluate their role in controlling EIAV.

Identification of human telomerase reverse transcriptase–derived peptides that induce HLA-A24–restricted antileukemia cytotoxic T lymphocytes

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2903-2907 ◽  
Author(s):  
Junko Arai ◽  
Masaki Yasukawa ◽  
Hideki Ohminami ◽  
Miki Kakimoto ◽  
Atsuhiko Hasegawa ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Reverse Transcriptase ◽  
Cytotoxic T Lymphocytes ◽  
Leukemia Cells ◽  
Telomerase Reverse Transcriptase ◽  
Malignant Cells ◽  
Human Telomerase Reverse Transcriptase ◽  
European Descent ◽  
Ctl Epitopes ◽  
Human Telomerase

Abstract Human telomerase reverse transcriptase (hTERT) is considered a potential target for cancer immunotherapy because it is preferentially expressed in malignant cells. hTERT-derived peptides carrying motifs for HLA-A24 (HLA-A*2402), the most common allele among Japanese and also frequently present in persons of European descent, were examined for their capacity to elicit antileukemia cytotoxic T lymphocytes (CTLs). Two of the 5 peptides tested, VYAETKHFL and VYGFVRACL, appeared capable of generating hTERT peptide-specific and HLA-A24–restricted CTLs. The CD8+ CTL clones specific for these hTERT peptides exerted cytotoxicity against leukemia cells in an HLA-A24–restricted manner. This cytotoxicity was inhibited by the addition of hTERT peptide-loaded autologous cells, suggesting that hTERT is naturally processed in leukemia cells and that hTERT-derived peptides are expressed on these cells and are recognized by CTLs in the context of HLA-A24. Taken together with the currently identified HLA-A2–restricted CTL epitopes derived from hTERT, identification of new CTL epitopes presented by HLA-A24 increases the feasibility of immunotherapy for leukemia using hTERT-derived peptides.

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