scholarly journals Cross-reactive CD4+ T cells enhance SARS-CoV-2 immune responses upon infection and vaccination

2021 ◽  
Author(s):  
Lucie Loyal ◽  
Julian Braun ◽  
Larissa Henze ◽  
Beate Kruse ◽  
Manuela Dingeldey ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Cross Reactivity ◽  
High Rate ◽  
Human Coronavirus ◽  
Peptide Epitope ◽  
Cross Immunity ◽  
Fusion Domain ◽  
Specific Peptide

While evidence for pre-existing SARS-CoV-2-cross-reactive CD4+ T cells in unexposed individuals is increasing, their functional significance remains unclear. Here, we comprehensively determined SARS-CoV-2-cross-reactivity and human coronavirus-reactivity in unexposed individuals. SARS-CoV-2-cross-reactive CD4+ T cells were ubiquitous, but their presence decreased with age. Within the spike glycoprotein fusion domain, we identified a universal immunodominant coronavirus-specific peptide epitope (iCope). Pre-existing spike- and iCope-reactive memory T cells were efficiently recruited into mild SARS-CoV-2 infections and their abundance correlated with higher IgG titers. Importantly, the cells were also reactivated after primary BNT162b2 COVID-19 mRNA vaccination in which their kinetics resembled that of secondary immune responses. Our results highlight the functional importance of pre-existing spike-cross-reactive T cells in SARS-CoV-2 infection and vaccination. Abundant spike-specific cross-immunity may be responsible for the unexpectedly high efficacy of current vaccines even with single doses and the high rate of asymptomatic/mild infection courses.

scholarly journals Cross-reactive CD4+ T cells enhance SARS-CoV-2 immune responses upon infection and vaccination

Science ◽  
2021 ◽  
pp. eabh1823
Author(s):  
Lucie Loyal ◽  
Julian Braun ◽  
Larissa Henze ◽  
Beate Kruse ◽  
Manuela Dingeldey ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
High Rate ◽  
Igg Antibodies ◽  
Rapid Induction ◽  
Cross Immunity ◽  
Functional Relevance ◽  
Intense Debate

The functional relevance of pre-existing cross-immunity to SARS-CoV-2 is a subject of intense debate. Here, we show that human endemic coronavirus (HCoV)-reactive and SARS-CoV-2-cross-reactive CD4+ T cells are ubiquitous but decrease with age. We identified a universal immunodominant coronavirus-specific spike peptide (S816-830) and demonstrate that pre-existing spike- and S816-830-reactive T cells were recruited into immune responses to SARS-CoV-2 infection and their frequency correlated with anti-SARS-CoV-2-S1-IgG antibodies. Spike-cross-reactive T cells were also activated after primary BNT162b2 COVID-19 mRNA vaccination displaying kinetics similar to secondary immune responses. Our results highlight the functional contribution of pre-existing spike-cross-reactive T cells in SARS-CoV-2 infection and vaccination. Cross-reactive immunity may account for the unexpectedly rapid induction of immunity following primary SARS-CoV-2 immunization and the high rate of asymptomatic/mild COVID-19 disease courses.

scholarly journals Shared TCR epitope cross-reactivity could permit dyads of Foxp3+ regulatory and IL-2-producing T cell precursors to escape thymic purge

2019 ◽  
Author(s):  
David Usharauli ◽  
Tirumalai Kamala
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Cross Reactivity ◽  
The Other ◽  
High Affinity ◽  
Mechanistic Basis ◽  
The One

The thymus-derived Foxp3+ regulatory T cells (Tregs) represent a unique population of CD4+ T cells responsible for maintaining dominant tolerance to auto-antigens, beneficial microbiota and potential irritants such as allergens on the one hand and efficient but balanced defense against pathogens on the other. How Tregs with high-affinity TCRs for thymically expressed epitopes survive thymic deletion or display such broad functionality is presently unclear. We recently introduced a novel framework dubbed SPIRAL (SPecific ImmunoRegulatory ALgorithm) which suggests that antigen cross-reactivity of thymic Treg repertoire could provide a mechanistic basis for its broad functionality. Here we further develop this model to propose how escape of high-affinity Tregs from thymic purge could be achieved in dyads with high-affinity natural IL-2-producing T cells (IL-2p T cells) sharing TCR epitope cross-reactivity. We believe this interpretation could reconcile contradictions related to Treg ontogeny in the thymus and their role in modulating antigen-specific immune responses.

scholarly journals Shared TCR epitope cross-reactivity could permit dyads of Foxp3+ regulatory and IL-2-producing T cell precursors to escape thymic purge

2019 ◽  
Author(s):  
David Usharauli ◽  
Tirumalai Kamala
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Cross Reactivity ◽  
The Other ◽  
High Affinity ◽  
Mechanistic Basis ◽  
The One

The thymus-derived Foxp3+ regulatory T cells (Tregs) represent a unique population of CD4+ T cells responsible for maintaining dominant tolerance to auto-antigens, beneficial microbiota and potential irritants such as allergens on the one hand and efficient but balanced defense against pathogens on the other. How Tregs with high-affinity TCRs for thymically expressed epitopes survive thymic deletion or display such broad functionality is presently unclear. We recently introduced a novel framework dubbed SPIRAL (SPecific ImmunoRegulatory ALgorithm) which suggests that antigen cross-reactivity of thymic Treg repertoire could provide a mechanistic basis for its broad functionality. Here we further develop this model to propose how escape of high-affinity Tregs from thymic purge could be achieved in dyads with high-affinity natural IL-2-producing T cells (IL-2p T cells) sharing TCR epitope cross-reactivity. We believe this interpretation could reconcile contradictions related to Treg ontogeny in the thymus and their role in modulating antigen-specific immune responses.

Abstract 1487: Cytotoxic CD4+ T cells contribute to anti-tumor immune responses in NSCLC

2021 ◽  
Author(s):  
Denise Lau ◽  
Sonal Khare ◽  
Derek Reiman ◽  
Tim Rand ◽  
Ameen A. Salahudeen ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd4 T Cells

scholarly journals Infection of HLA-DR1 Transgenic Mice with a Human Isolate of Influenza A Virus (H1N1) Primes a Diverse CD4 T-Cell Repertoire That Includes CD4 T Cells with Heterosubtypic Cross-Reactivity to Avian (H5N1) Influenza Virus

2009 ◽  
Vol 83 (13) ◽  
pp. 6566-6577 ◽  
Author(s):  
Katherine A. Richards ◽  
Francisco A. Chaves ◽  
Andrea J. Sant
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
T Cell ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Cd4 T Cells ◽  
Cross Reactivity ◽  
Cd4 T Cell ◽  
Ns1 Protein ◽  
Infected Cells

ABSTRACT The specificity of the CD4 T-cell immune response to influenza virus is influenced by the genetic complexity of the virus and periodic encounters with variant subtypes and strains. In order to understand what controls CD4 T-cell reactivity to influenza virus proteins and how the influenza virus-specific memory compartment is shaped over time, it is first necessary to understand the diversity of the primary CD4 T-cell response. In the study reported here, we have used an unbiased approach to evaluate the peptide specificity of CD4 T cells elicited after live influenza virus infection. We have focused on four viral proteins that have distinct intracellular distributions in infected cells, hemagglutinin (HA), neuraminidase (NA), nucleoprotein, and the NS1 protein, which is expressed in infected cells but excluded from virion particles. Our studies revealed an extensive diversity of influenza virus-specific CD4 T cells that includes T cells for each viral protein and for the unexpected immunogenicity of the NS1 protein. Due to the recent concern about pandemic avian influenza virus and because CD4 T cells specific for HA and NA may be particularly useful for promoting the production of neutralizing antibody to influenza virus, we have also evaluated the ability of HA- and NA-specific CD4 T cells elicited by a circulating H1N1 strain to cross-react with related sequences found in an avian H5N1 virus and find substantial cross-reactivity, suggesting that seasonal vaccines may help promote protection against avian influenza virus.

scholarly journals The effect of Kefir on The Immune Response of Healthy Volunteers In Vitro

2017 ◽  
Vol 3 (2) ◽  
pp. 28
Author(s):  
Desie Dwi Wisudanti
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Immune Responses ◽  
Healthy Volunteers ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Fermented Milk ◽  
Bioactive Components ◽  
Ifn Γ

Kefir is a functional foodstuff of probiotics, made from fermented milk with kefir grains containing various types of beneficial bacteria and yeast. There have been many studies on the effects of oral kefir on the immune system, but few studies have shown the effect of bioactive components from kefir (peptides and exopolysaccharides/ kefiran), on immune responses. The purpose of this study was to prove the effect of kefir supernatant from milk goat on healthy immune volunteer response in vitro. The study was conducted on 15 healthy volunteers, then isolated PBMC from whole blood, then divided into 5 groups (K-, P1, P2, P3 and P4) before culture was done for 4 days. The harvested cells from culture were examined for the percentage of CD4+ T cells, CD8+ T cells, IFN-γ, IL-4 using flowsitometry and IL-2 levels, IL-10 using the ELISA method. The results obtained that kefir do not affect the percentage of CD4+ T cells and CD8+ T cells. The higher the concentration of kefir given, the higher levels of secreted IFN- γ and IL-4, but a decrease in IL-2 levels. Significant enhancement occurred at levels of IL-10 culture PBMC given kefir with various concentrations (p <0.01), especially at concentrations of 1%. These results also show the important effects of kefir bioactive components on immune responses. The conclusion of this study is that kefir can improve the immune response, through stimulation of IL-10 secretion in vitro.

scholarly journals Expanded circulating follicular dendritic cells facilitate immune responses in chronic HBV infection

2020 ◽  
Author(s):  
Xiaoyi Li ◽  
Qifan Zhang ◽  
Wanyue Zhang ◽  
Guofu Ye ◽  
Yanchen Ma ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
B Cells ◽  
Hepatitis B ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Hbv Infection ◽  
Follicular Dendritic Cells ◽  
Chronic Hbv Infection ◽  
Chronic Hbv

Abstract Background: The restoration of host hepatitis B virus (HBV)-specific antiviral immunity is an effective strategy for hepatitis B recovery. Follicular dendritic cells (FDCs) play a crucial role in immune regulation. The goal of the present study was to investigate the characteristics and functions of FDCs in chronic HBV infection. Methods: The frequencies of FDCs in peripheral blood, liver, and spleen were measured in patients with chronic HBV infection. Isolated FDCs from splenic tissues of HBV-related liver cirrhosis-induced hypersplenism patients were cultured with autologous intrasplenic CD4 + T cells and CD19 + B cells.Results: We found that patients with chronic HBV infection had a significantly increased frequency of circulating FDCs compared with that of healthy controls. Additionally, the frequency of circulating FDCs was positively correlated with that of intrahepatic and intrasplenic counterparts. Moreover, a positive correlation between the frequency of circulating FDCs and plasmablast and memory B cells, as well as C-X-C motif chemokine receptor type 5 (CXCR5) + CD4 + T cells and CXCR5 + CD8 + T cells was also observed. Notably, in vitro experiments demonstrated that FDCs derived from splenic tissues of chronic HBV patients facilitated interferon-γ and interleukin-21 production from autologous intrasplenic CD4 + T cells and promoted the proliferation of autologous intrasplenic CD19 + B cells. Conclusions: Expanded FDCs in patients with chronic HBV infection may favor the host immune responses against HBV. The identification of this unique population may contribute to a better understanding of the immune regulatory mechanisms and provide a potential immunotherapeutic target in chronic HBV infection.

Su.67. Monocytes Modulate T-Cell Immune Responses in a Pge2-Cox-2 Dependent Manner and Induce Foxp3+-Cd4+- T-Cells

2006 ◽  
Vol 119 ◽  
pp. S183
Author(s):  
Sheraz Yaqub ◽  
Tone Bryn ◽  
Milada Mahic ◽  
Einar Aandahl ◽  
Kjetil Tasken
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Dependent Manner ◽  
T Cell Immune Responses ◽  
Cox 2

Age Influences Recovery of Systemic and Mucosal Immune Responses Following Acute Depletion of CD4 T Cells

1993 ◽  
Vol 69 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Audrey L. Fleming ◽  
Elizabeth H. Field ◽  
Naser Tolaymat ◽  
John S. Cowdery
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Mucosal Immune Responses
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