scholarly journals Antigen-driven C–C Chemokine-mediated HIV-1 Suppression by CD4+ T Cells from Exposed Uninfected Individuals Expressing the Wild-type CCR-5 Allele

1997 ◽  
Vol 186 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Lucinda Furci ◽  
Gabriella Scarlatti ◽  
Samuele Burastero ◽  
Giuseppe Tambussi ◽  
Claudia Colognesi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccine Development ◽  
Specific Antigen ◽  
T Cell Response ◽  
Wild Type ◽  
Cell Immunity ◽  
Base Pair Deletion ◽  
Exposed Uninfected ◽  
Hiv 1

Despite repeated exposure to HIV-1, certain individuals remain persistently uninfected. Such exposed uninfected (EU) people show evidence of HIV-1–specific T cell immunity and, in rare cases, selective resistance to infection by macrophage-tropic strains of HIV-1. The latter has been associated with a 32–base pair deletion in the C–C chemokine receptor gene CCR-5, the major coreceptor of macrophage-tropic strains of HIV-1. We have undertaken an analysis of the HIV-specific T cell responses in 12 EU individuals who were either homozygous for the wild-type CCR-5 allele or heterozygous for the deletion allele (CCR-5Δ32). We have found evidence of an oligoclonal T cell response mediated by helper T cells specific for a conserved region of the HIV-1 envelope. These cells produce very high levels of C–C chemokines when stimulated by the specific antigen and suppress selectively the replication of macrophage-tropic, but not T cell–tropic, strains of HIV-1. These chemokine-producing helper cells may be part of a protective immune response that could be potentially exploited for vaccine development.

scholarly journals Lack of CD4+ T Cells Does Not Affect Induction of CD8+ T-Cell Immunity against Encephalitozoon cuniculi Infection

2000 ◽  
Vol 68 (11) ◽  
pp. 6223-6232 ◽  
Author(s):  
Magali Moretto ◽  
Lori Casciotti ◽  
Brigit Durell ◽  
Imtiaz A. Khan
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
T Cell Response ◽  
T Cell Immunity ◽  
Cell Mediated Immunity ◽  
Wild Type ◽  
Encephalitozoon Cuniculi ◽  
Cell Immunity ◽  
Mouse Tissues

ABSTRACT Cell-mediated immunity has been reported to play an important role in defense against Encephalitozoon cuniculi infection. Previous studies from our laboratory have underlined the importance of cytotoxic CD8+ T lymphocytes (CTL) in survival of mice infected with E. cuniculi. In the present study, immune response against E. cuniculi infection in CD4+T-cell-deficient mice was evaluated. Similar to resistant wild-type animals, CD4−/− mice were able to resolve E. cuniculi infection even at a very high challenge dose (5 × 107 spores/mouse). Tissues from infected CD4−/− mice did not exhibit higher parasite loads in comparison to the parental wild-type mice. Conversely, at day 21 postinfection, susceptible CD8−/− mice had 1014 times more parasites in the liver compared to control wild-type mice. Induction of the CD8+ T-cell response in CD4−/− mice against E. cuniculi infection was studied. Interestingly, a normal antigen-specific CD8+T-cell response to E. cuniculi infection was observed in CD4−/− mice (precursor proliferation frequency, 1/2.5 × 104 versus 1/104 in wild-type controls). Lack of CD4+ T cells did not alter the magnitude of the antigen-specific CTL response (precursor CTL frequency; 1/1.4 × 104 in CD4−/− mice versus 1/3 × 104 in control mice). Adoptive transfer of immune CD8+ T cells from both CD4−/− and wild-type animals prevented the mortality in CD8−/− mice.E. cuniculi infection thus offers an example of an intracellular parasitic infection where CD8+ T-cell immunity can be induced in the absence of CD4+ T cells.

scholarly journals T Cell Immunity Evaluation and Immunodominant Epitope T Cell Receptor Identification of Severe Acute Respiratory Syndrome Coronavirus 2 Spike Glycoprotein in COVID-19 Convalescent Patients

2021 ◽  
Vol 9 ◽  
Author(s):  
Luo Li ◽  
Qian Chen ◽  
Xiaojian Han ◽  
Meiying Shen ◽  
Chao Hu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Severe Acute Respiratory Syndrome ◽  
Vaccine Development ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cell Immunity ◽  
Ifn Γ

A better understanding of the role of T cells in the immune response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is helpful not only for vaccine development but also for the treatment of COVID-19 patients. In this study, we determined the existence of SARS-CoV-2-specific T cells in the blood of COVID-19 convalescents. Meanwhile, the specific T cell response in the non-RBD region was stronger than in the RBD region. We also found that SARS-CoV-2 S-specific reactive CD4+ T cells exhibited higher frequency than CD8+ T cells in recovered COVID-19 patients, with greater number of corresponding epitopes presented. Importantly, we isolated the SARS-CoV-2-specific CD4+ T cell receptors (TCRs) and inserted the TCRs into allogenic CD4+ T cells. These TCR-T cells can be activated by SARS-CoV-2 spike peptide and produce IFN-γ in vitro. These results might provide valuable information for the development of vaccines and new therapies against COVID-19.

scholarly journals Mechanisms that allow vaccination against an oncolytic vesicular stomatitis virus-encoded transgene to enhance safety without abrogating oncolysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amanda W. K. AuYeung ◽  
Robert C. Mould ◽  
Ashley A. Stegelmeier ◽  
Jacob P. van Vloten ◽  
Khalil Karimi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vesicular Stomatitis Virus ◽  
Cell Response ◽  
Viral Infections ◽  
T Cell Response ◽  
Oncolytic Viruses ◽  
Oncolytic Virotherapy ◽  
Cell Immunity ◽  
Vesicular Stomatitis

AbstractVaccination can prevent viral infections via virus-specific T cells, among other mechanisms. A goal of oncolytic virotherapy is replication of oncolytic viruses (OVs) in tumors, so pre-existing T cell immunity against an OV-encoded transgene would seem counterproductive. We developed a treatment for melanomas by pre-vaccinating against an oncolytic vesicular stomatitis virus (VSV)-encoded tumor antigen. Surprisingly, when the VSV-vectored booster vaccine was administered at the peak of the primary effector T cell response, oncolysis was not abrogated. We sought to determine how oncolysis was retained during a robust T cell response against the VSV-encoded transgene product. A murine melanoma model was used to identify two mechanisms that enable this phenomenon. First, tumor-infiltrating T cells had reduced cytopathic potential due to immunosuppression. Second, virus-induced lymphopenia acutely removed virus-specific T cells from tumors. These mechanisms provide a window of opportunity for replication of oncolytic VSV and rationale for a paradigm change in oncolytic virotherapy, whereby immune responses could be intentionally induced against a VSV-encoded melanoma-associated antigen to improve safety without abrogating oncolysis.

scholarly journals Human Immunodeficiency Virus Type 1 (HIV-1)-Specific CD8+ TEMRA Cells in Early Infection Are Linked to Control of HIV-1 Viremia and Predict the Subsequent Viral Load Set Point

2007 ◽  
Vol 81 (11) ◽  
pp. 5759-5765 ◽  
Author(s):  
John W. Northfield ◽  
Christopher P. Loo ◽  
Jason D. Barbour ◽  
Gerald Spotts ◽  
Frederick M. Hecht ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Absolute Number ◽  
T Cell Response ◽  
Effector Memory ◽  
Set Point ◽  
Effector Memory T Cells ◽  
Viral Load Set Point ◽  
Hiv 1

ABSTRACT CD8+ T cells are believed to play an important role in the control of human immunodeficiency virus type 1 (HIV-1) infection. However, despite intensive efforts, it has not been possible to consistently link the overall magnitude of the CD8+ T-cell response with control of HIV-1. Here, we have investigated the association of different CD8+ memory T-cell subsets responding to HIV-1 in early infection with future control of HIV-1 viremia. Our results demonstrate that both a larger proportion and an absolute number of HIV-1-specific CD8+ CCR7− CD45RA+ effector memory T cells (TEMRA cells) were associated with a lower future viral load set point. In contrast, a larger absolute number of HIV-1-specific CD8+ CCR7− CD45RA− effector memory T cells (TEM) was not related to the viral load set point. Overall, the findings suggest that CD8+ TEMRA cells have superior antiviral activity and indicate that both qualitative and quantitative aspects of the CD8+ T-cell response need to be considered when defining the characteristics of protective immunity to HIV-1.

scholarly journals TCR Repertoire Characterization for T Cells Expanded in Response to hRSV Infection in Mice Immunized with a Recombinant BCG Vaccine

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 233
Author(s):  
Emma Rey-Jurado ◽  
Karen Bohmwald ◽  
Hernán G. Correa ◽  
Alexis M. Kalergis
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Response ◽  
Bcg Vaccine ◽  
Lung Damage ◽  
Cell Repertoire ◽  
Cell Immunity ◽  
Tcr Repertoire ◽  
Syncytial Virus

T cells play an essential role in the immune response against the human respiratory syncytial virus (hRSV). It has been described that both CD4+ and CD8+ T cells can contribute to the clearance of the virus during an infection. However, for some individuals, such an immune response can lead to an exacerbated and detrimental inflammatory response with high recruitment of neutrophils to the lungs. The receptor of most T cells is a heterodimer consisting of α and β chains (αβTCR) that upon antigen engagement induces the activation of these cells. The αβTCR molecule displays a broad sequence diversity that defines the T cell repertoire of an individual. In our laboratory, a recombinant Bacille Calmette–Guérin (BCG) vaccine expressing the nucleoprotein (N) of hRSV (rBCG-N-hRSV) was developed. Such a vaccine induces T cells with a Th1 polarized phenotype that promote the clearance of hRSV infection without causing inflammatory lung damage. Importantly, as part of this work, the T cell receptor (TCR) repertoire of T cells expanded after hRSV infection in naïve and rBCG-N-hRSV-immunized mice was characterized. A more diverse TCR repertoire was observed in the lungs from rBCG-N-hRSV-immunized as compared to unimmunized hRSV-infected mice, suggesting that vaccination with the recombinant rBCG-N-hRSV vaccine triggers the expansion of T cell populations that recognize more viral epitopes. Furthermore, differential expansion of certain TCRVβ chains was found for hRSV infection (TCRVβ+8.3 and TCRVβ+5.1,5.2) as compared to rBCG-N-hRSV vaccination (TCRVβ+11 and TCRVβ+12). Our findings contribute to better understanding the T cell response during hRSV infection, as well as the functioning of a vaccine that induces a protective T cell immunity against this virus.

scholarly journals DNA gag/Adenovirus Type 5 (Ad5) gag and Ad5 gag/Ad5 gag Vaccines Induce Distinct T-Cell Response Profiles

2008 ◽  
Vol 82 (16) ◽  
pp. 8161-8171 ◽  
Author(s):  
Kara S. Cox ◽  
James H. Clair ◽  
Michael T. Prokop ◽  
Kara J. Sykes ◽  
Sheri A. Dubey ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
T Cell Responses ◽  
Adenovirus Type ◽  
T Cell Response ◽  
Cell Responses ◽  
Response Profiles ◽  
Adenovirus Type 5 ◽  
Hiv 1

ABSTRACT Results from Merck's phase II adenovirus type 5 (Ad5) gag/pol/nef test-of-concept trial showed that the vaccine lacked efficacy against human immunodeficiency virus (HIV) infection in a high-risk population. Among the many questions to be explored following this outcome are whether (i) the Ad5 vaccine induced the quality of T-cell responses necessary for efficacy and (ii) the lack of efficacy in the Ad5 vaccine can be generalized to other vector approaches intended to induce HIV type 1 (HIV-1)-specific T-cell responses. Here we present a comprehensive evaluation of the T-cell response profiles from cohorts of clinical trial subjects who received the HIV CAM-1 gag insert delivered by either a regimen with DNA priming followed by Ad5 boosting (n = 50) or a homologous Ad5/Ad5 prime-boost regimen (n = 70). The samples were tested using a statistically qualified nine-color intracellular cytokine staining assay measuring interleukin-2 (IL-2), tumor necrosis factor alpha, macrophage inflammatory protein 1β, and gamma interferon production and expression of CD107a. Both vaccine regimens induced CD4+ and CD8+ HIV gag-specific T-cell responses which variably expressed several intracellular markers. Several trends were observed in which the frequencies of HIV-1-specific CD4+ T cells and IL-2 production from antigen-specific CD8+ T cells in the DNA/Ad5 cohort were more pronounced than in the Ad5/Ad5 cohort. Implications of these results for future vaccine development will be discussed.

scholarly journals Dendritic cells transduced by multiply deleted HIV-1 vectors exhibit normal phenotypes and functions and elicit an HIV-specific cytotoxic T-lymphocyte response in vitro

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1327-1333 ◽  
Author(s):  
Andreas Gruber ◽  
June Kan-Mitchell ◽  
Kelli L. Kuhen ◽  
Tetsu Mukai ◽  
Flossie Wong-Staal
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Response ◽  
Adoptive T Cell Therapy ◽  
Cytotoxic T Cell ◽  
T Cell Therapy ◽  
Hiv 1

Abstract Dendritic cells (DCs) genetically modified to continually express and present antigens may be potent physiologic adjuvants for induction of prophylactic or therapeutic immunity. We have previously shown that an env and nef deleted HIV-1 vector (HIV-1ΔEN) pseudotyped with VSV-G transduced monocyte-derived macrophages as well as CD34+ precursors of DCs. Here we extended these findings with HIV-1ΔEN to highly differentiated human DCs derived in culture from circulating monocytes (DCs). In addition, a new vector derived from HIV-1ΔEN but further deleted in its remaining accessory genes vif, vpr, and vpu(HIV-1ΔEN V3) was also tested. Both vectors efficiently transduced DCs. Transduction of DCs did not significantly alter their viability or their immunophenotype when compared with untransduced DCs. Furthermore, the phagocytic potential of immature DCs, as well as their ability to differentiate into mature DCs capable of stimulating T-cell proliferation, was not affected. Finally, DCs transduced by the HIV-1ΔEN vector were able to elicit a primary antiviral cytotoxic T-cell response in autologous CD8 T cells. These results suggest that HIV-1–based vectors expressing viral antigens may be useful for in vivo active immunization as well as ex vivo priming of cytotoxic T cells for adoptive T-cell therapy.

scholarly journals Long-Term Control of HIV-1 in Hemophiliacs Carrying Slow-Progressing Allele HLA-B*5101

2010 ◽  
Vol 84 (14) ◽  
pp. 7151-7160 ◽  
Author(s):  
Yuka Kawashima ◽  
Nozomi Kuse ◽  
Hiroyuki Gatanaga ◽  
Takuya Naruto ◽  
Mamoru Fujiwara ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cytotoxic T Lymphocyte ◽  
T Cell Response ◽  
Slow Progression ◽  
Lack Of Control ◽  
Escape Mutants ◽  
Hiv 1

ABSTRACT HLA-B*51 alleles are reported to be associated with slow disease progression to AIDS, but the mechanism underlying this association is still unclear. In the present study, we analyzed the effect of HLA-B*5101 on clinical outcome for Japanese hemophiliacs who had been infected with HIV-1 before 1985 and had been recruited in 1998 for this study. HLA-B*5101+ hemophiliacs exhibited significantly slow progression. The analysis of HLA-B*5101-restricted HIV-1-specific cytotoxic T-lymphocyte (CTL) responses to 4 HLA-B*-restricted epitopes in 10 antiretroviral-therapy (ART)-free HLA-B*5101+ hemophiliacs showed that the frequency of Pol283-8-specific CD8+ T cells was inversely correlated with the viral load, whereas the frequencies of CD8+ T cells specific for 3 other epitopes were positively correlated with the viral load. The HLA-B*5101+ hemophiliacs whose HIV-1 replication had been controlled for approximately 25 years had HIV-1 possessing the wild-type Pol283-8 sequence or the Pol283-8V mutant, which does not critically affect T-cell recognition, whereas other HLA-B*5101+ hemophiliacs had HIV-1 with escape mutations in this epitope. The results suggest that the control of HIV-1 over approximately 25 years in HLA-B*5101-positive hemophiliacs is associated with a Pol283-8-specific CD8+ T-cell response and that lack of control of HIV-1 is associated with the appearance of Pol283-8-specific escape mutants.

scholarly journals Key role of T cell defects in age-related vulnerability to West Nile virus

2009 ◽  
Vol 206 (12) ◽  
pp. 2735-2745 ◽  
Author(s):  
James D. Brien ◽  
Jennifer L. Uhrlaub ◽  
Alec Hirsch ◽  
Clayton A. Wiley ◽  
Janko Nikolich-Žugich
Keyword(s):  
T Cells ◽  
West Nile Virus ◽  
T Cell ◽  
Cd8 T Cells ◽  
The Elderly ◽  
T Cell Response ◽  
West Nile ◽  
Immunodeficient Mice ◽  
Age Related ◽  
Cell Immunity

West Nile virus (WNV) infection causes a life-threatening meningoencephalitis that becomes increasingly more prevalent over the age of 50 and is 40–50× more prevalent in people over the age of 70, compared with adults under the age of 40. In a mouse model of age-related vulnerability to WNV, we demonstrate that death correlates with increased viral titers in the brain and that this loss of virus control with age was the result of defects in the CD4 and CD8 T cell response against WNV. Specific age-related defects in T cell responses against dominant WNV epitopes were detected at the level of cytokine and lytic granule production, each of which are essential for resistance against WNV, and in the ability to generate multifunctional anti-WNV effector T cells, which are believed to be critical for robust antiviral immunity. In contrast, at the peak of the response, old and adult T cells exhibited superimposable peptide sensitivity. Most importantly, although the adult CD4 or CD8 T cells readily protected immunodeficient mice upon adoptive transfer, old T cells of either subset were unable to provide WNV-specific protection. Consistent with a profound qualitative and quantitative defect in T cell immunity, old brains contained at least 12× fewer total effector CD8 T cells compared with adult mice at the peak of brain infection. These findings identify potential targets for immunomodulation and treatment to combat lethal WNV infection in the elderly.

scholarly journals Growth, Virulence, and Immunogenicity of Listeria monocytogenes aro Mutants

2004 ◽  
Vol 72 (10) ◽  
pp. 5622-5629 ◽  
Author(s):  
Jochen Stritzker ◽  
Jozef Janda ◽  
Christoph Schoen ◽  
Marcus Taupp ◽  
Sabine Pilgrim ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
T Cell ◽  
Cell Response ◽  
Culture Media ◽  
Lethal Dose ◽  
T Cell Response ◽  
Wild Type ◽  
Protein Antigens ◽  
Cell Immunity ◽  
Virulence Attenuation

ABSTRACT Mutants of Listeria monocytogenes with deletions in genes of the common branch of the biosynthesis pathway leading to aromatic compounds were constructed as possible virulence-attenuated carrier strains for protein antigens or vaccine DNA. aroA, aroB, and in particular aroE mutants showed strongly reduced growth rates in epithelial cells and even in rich culture media. The metabolism of the aro mutants under these conditions was predominantly anaerobic. Aerobic metabolism and a wild-type growth rate were, however, regained upon the addition of vitamin K2, suggesting that the aro mutants are deficient in oxidative respiration due to the lack of menaquinone. Replication of the aro mutants in the host cell's cytosol and cell-to-cell spread were drastically slowed down, and all aro mutants showed high virulence attenuation in mice, i.e., the 50% lethal dose in BALB/c mice was increased at least 104-fold for the aroA, aroB, and aroA/B mutants and >105-fold for the aroE mutant compared to the parent strain. Nevertheless, mice preimmunized with aro mutant bacteria elicited good T-cell response and full protection against a subsequent challenge with the virulent wild-type strain. A total of 5 × 106 aroA, aroB, and aroA/B mutant bacteria were sufficient to obtain a protective T-cell response, while 5 × 108 aroE or aroA/E mutants were necessary to achieve comparable numbers of antigen-specific T cells. These numbers were well tolerated without causing any signs of disease, indicating that Listeria strains with deletions in genes of the basic branch of the aromatic amino acid pathway could be useful vaccine carriers for inducing T-cell immunity.

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