scholarly journals Thymosin alpha-1 Protected T Cells from Excessive Activation in Severe COVID-19

2020 ◽  
Author(s):  
Kuai Yu ◽  
Yongjian Wu ◽  
Jingjing He ◽  
Xuefei Liu ◽  
Bo Wei ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Adaptive Immunity ◽  
Adaptive Immune Responses ◽  
Activated T Cells ◽  
T Effector Cells ◽  
Adaptive Immune ◽  
The Impact ◽  
Excessive Activation

Abstract Two typical features of uncontrolled inflammation, cytokine storm and lymphopenia, are associated with the severity of coronavirus disease 2019 (COVID-19), demonstrating that both innate and adaptive immune responses are involved in the development of this disease. Recent studies have explored the contribution of innate immune cells to the pathogenesis of the infection. However, the impact of adaptive immunity on this disease remains unknown. In order to clarify the role of adaptive immune response in COVID-19, we characterized the phenotypes of lymphocytes in PBMCs from patients at different disease stages using single-cell RNA sequencing (scRNA-seq) technology. Dynamics of the effector cell levels in lymphocytes revealed a distinct feature of adaptive immunity in severely affected patients, the coincidence of impaired cellular and enhanced humoral immune responses, suggesting that dysregulated adaptive immune responses advanced severe COVID-19. Excessive activation and exhaustion were observed in CD8 T effector cells, which might contribute to the lymphopenia. Interestingly, expression of Prothymosin alpha (PTMA), the proprotein of Tα1, was significantly increased in a group of CD8 T memory stem cells, but not in excessively activated T cells. We further showed that Tα1 significantly promoted the proliferation of activated T cells in vitro and relieved the lymphopenia in COVID-19 patients. Our data suggest that protection of T cells from excessive activation might be critical for the prevention of severe COVID-19.

scholarly journals Thymosin alpha-1 Protected T Cells from Excessive Activation in Severe COVID-19

2020 ◽  
Author(s):  
Kuai Yu ◽  
Yongjian Wu ◽  
Jingjing He ◽  
Xuefei Liu ◽  
Bo Wei ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Severe Disease ◽  
Adaptive Immune Responses ◽  
Activated T Cells ◽  
Adaptive Immune ◽  
The Impact ◽  
Excessive Activation

Abstract Two typical features of uncontrolled inflammation, cytokine storm and lymphopenia, are associated with the severity of coronavirus disease 2019 (COVID-19), demonstrating that both innate and adaptive immune responses are involved in the development of this disease. Recent studies have explored the contribution of innate immune cells to the pathogenesis of the infection. However, the impact of adaptive immunity on this disease remains unknown. In order to clarify the role of adaptive immune response in COVID-19, we characterized the phenotypes of lymphocytes in PBMCs from patients at different disease stages using single-cell RNA sequencing (scRNA-seq) technology. Dynamics of the effector cell levels in lymphocytes revealed dysregulated adaptive immune responses in patients with severe disease. A new cluster of excessively activated CD8 T cells (Tea) was further identified, which displayed exhausted phenotypes and diminished function of antigen recognition. Interestingly, expression of PTMA, the proprotein of Tα1, was significantly increased in a group of highly proliferating CD8 T cells with memory stem cell features. We further showed that Tα1 significantly promoted the proliferation of activated T cells in vitro and relieved the lymphopenia in COVID-19 patients. Our data suggest that protection of T cells from excessive activation might be critical for the prevention of severe COVID-19.

scholarly journals In Vitro Platform Establishes Antigen-Specific CD8+ T Cell Cytotoxicity to Encapsulated Cells via Indirect Antigen Recognition

2019 ◽  
Author(s):  
Ying Li ◽  
Anthony W. Frei ◽  
Ethan Y. Yang ◽  
Irayme Labrada-Miravet ◽  
Chuqiao Sun ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immune Recognition ◽  
Adaptive Immune Responses ◽  
Activated T Cells ◽  
Encapsulated Cells ◽  
Adaptive Immune

AbstractCell replacement therapy has the potential to cure diseases caused by the absence or malfunction of specialized cells. A substantial impediment to the success of any non-autologous cellular transplant is the need for systemic immunosuppressive drugs to prevent host-mediated rejection of the foreign cells. Cellular encapsulation, i.e., the entrapment of cells within stable polymeric hydrogels, has been clinically explored to prevent host immune recognition and attack, but the efficacy of these encapsulated grafts is poor. While several studies have explored improvements in innate immune acceptance of these encapsulated cells, little attention has been paid to the roles of adaptive immune responses, specifically graft-targeting T cell activation, in graft destabilization. Herein, we established an efficient, single-antigen in vitro platform capable of delineating direct and indirect host T cell recognition to microencapsulated cellular grafts and evaluating their consequential impacts. Using alginate as the model hydrogel, encapsulated membrane-bound ovalbumin (mOVA) stimulator cells were incubated with antigen-specific OTI lymphocytes and subsequent OVA-specific CD8+ T cell activation and effector function were quantified. We established that alginate microencapsulation abrogates direct T cell activation by interrupting donor-host interaction; however, indirect T cell activation mediated by host antigen presenting cells (APCs) primed with shed donor antigens still occurs. These activated T cells imparted cytotoxicity on the encapsulated cells, likely via diffusion of cytotoxic solutes. Overall, this platform delivers unique mechanistic insight into the impacts of hydrogel encapsulation on host adaptive immune responses, as well as a tool for the efficient immune screening on new encapsulation methods and/or synergistic immunomodulatory agents.

scholarly journals Anti-Telomerase CD4+ Th1 Immunity and Monocytic-Myeloid-Derived-Suppressor Cells Are Associated with Long-Term Efficacy Achieved by Docetaxel, Cisplatin, and 5-Fluorouracil (DCF) in Advanced Anal Squamous Cell Carcinoma: Translational Study of Epitopes-HPV01 and 02 Trials

2020 ◽  
Vol 21 (18) ◽  
pp. 6838 ◽  
Author(s):  
Laurie Spehner ◽  
Stefano Kim ◽  
Angélique Vienot ◽  
Eric François ◽  
Bruno Buecher ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
T Cells ◽  
Immune Responses ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Adaptive Immune Responses ◽  
Anal Squamous Cell Carcinoma ◽  
Adaptive Immune ◽  
Immunosuppressive Cells ◽  
The Impact

Docetaxel, cisplatin and 5-fluorouracil (DCF) chemotherapy regimen is highly effective in advanced anal squamous cell carcinoma (SCCA), as demonstrated by the Epitopes-HPV02 study results. Here, we analyzed the impact of DCF regimen and the prognostic value of adaptive immune responses and immunosuppressive cells in SCCA patients included in two prospective studies (Epitopes-HPV01 and HPV02). The presence of T-cell responses against Human papillomavirus (HPV)16-E6/E7 and anti-telomerase (hTERT)-antigens was measured by IFNᵧ-ELISpot. Here, we showed that HPV-adaptive immune responses are increased in SCCA patients. SCCA patients also displayed enhanced circulating TH1 T-cells restricted by hTERT. Exposition to DCF increased hTERT immunity but not HPV or common viruses immune responses. Notably, the correlation of hTERT immune responses with SCCA patients’ clinical outcomes highlights that hTERT is a relevant antigen in this HPV-related disease. The influence of peripheral immunosuppressive cells was investigated by flow cytometry. While both regulatory T-cells and monocytic-myeloid-derived suppressive cells (M-MDSC) accumulated in the peripheral blood of SCCA patients, only high levels of M-MDSC were negatively correlated with hTERT adaptive immune responses and predicted poor prognosis. Altogether, our results reveal that hTERT is a relevant antigen in HPV-driven SCCA disease and that M-MDSC levels influence TH1-adaptive immune responses and patients’ survival.

Coexpression of αβ and γδ TCRs bridges innate and adaptive immunity

2020 ◽  
Vol 12 (546) ◽  
pp. eabc8941
Author(s):  
Gerald P. Morris
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Adaptive Immunity ◽  
Γδ T Cells ◽  
Adaptive Immune Responses ◽  
Innate And Adaptive Immunity ◽  
Adaptive Immune

T cells coexpressing αβ and γδ TCRs demonstrate characteristics of both αβ and γδ T cells, providing a link between innate and adaptive immune responses.

scholarly journals Human natural killer cells mediate adaptive immunity to viral antigens

2019 ◽  
Vol 4 (35) ◽  
pp. eaat8116 ◽  
Author(s):  
Rana Nikzad ◽  
Laura S. Angelo ◽  
Kevin Aviles-Padilla ◽  
Duy T. Le ◽  
Vipul K. Singh ◽  
...  
Keyword(s):  
Immune Responses ◽  
Nk Cells ◽  
Natural Killer ◽  
Adaptive Immunity ◽  
Human Memory ◽  
Humanized Mice ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
Human Volunteers

Adaptive immune responses are defined as antigen sensitization–dependent and antigen-specific responses leading to establishment of long-lived immunological memory. Although natural killer (NK) cells have traditionally been considered cells of the innate immune system, mounting evidence in mice and nonhuman primates warrants reconsideration of the existing paradigm that B and T cells are the sole mediators of adaptive immunity. However, it is currently unknown whether human NK cells can exhibit adaptive immune responses. We therefore tested whether human NK cells mediate adaptive immunity to virally encoded antigens using humanized mice and human volunteers. We found that human NK cells displayed vaccination-dependent, antigen-specific recall responses in vitro, when isolated from livers of humanized mice previously vaccinated with HIV-encoded envelope protein. Furthermore, we discovered that large numbers of cytotoxic NK cells with a tissue-resident phenotype were recruited to sites of varicella-zoster virus (VZV) skin test antigen challenge in VZV-experienced human volunteers. These NK-mediated recall responses in humans occurred decades after initial VZV exposure, demonstrating that NK memory in humans is long-lived. Our data demonstrate that human NK cells exhibit adaptive immune responses upon vaccination or infection. The existence of human memory NK cells may allow for the development of vaccination-based approaches capable of establishing potent NK-mediated memory functions contributing to host protection.

scholarly journals Attenuation of antigen-specific T helper 1 immunity by Neolitsea hiiranensis and its derived terpenoids

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2758 ◽  
Author(s):  
Yin-Hua Cheng ◽  
Ih-Sheng Chen ◽  
Ying-Chi Lin ◽  
Chun-Wei Tung ◽  
Hsun-Shuo Chang ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Caryophyllene Oxide ◽  
Immune Disorders ◽  
T Helper ◽  
T Helper 1 ◽  
Adaptive Immune Responses ◽  
Adaptive Immune

Background T cells play a pivotal role in the adaptive immunity that participates in a wide range of immune responses through a complicated cytokine network. Imbalance of T-cell responses is involved in several immune disorders. Neolitsea species, one of the biggest genera in the family Lauraceae, have been employed widely as folk medicines for a long time in Asia. Previous phytochemical investigations revealed the abundance of terpenes in the leaves of N. hiiranensis, an endemic Neolitsea in Taiwan, and demonstrated anti-inflammatory activities. However, the effect of N. hiiranensis on the functionality of immune cells, especially T cells, is still unclear. In this study, we utilize in vitro and in vivo approaches to characterize the effects of leaves of N. hiiranensis and its terpenoids on adaptive immune responses. Methods Dried leaves of N. hiiranensis were extracted three times with cold methanol to prepare crude extracts and to isolate its secondary metabolites. The ovalbumin (OVA)-sensitized BALB/c mice were administrated with N. hiiranensis extracts (5–20 mg/kg). The serum and splenocytes of treated mice were collected to evaluate the immunomodulatory effects of N. hiiranensis on the production of OVA-specific antibodies and cytokines. To further identify the N. hiiranensis-derived compounds with immunomodulatory potentials, OVA-primed splenocytes were treated with compounds isolated from N. hiiranensis by determining the cell viability, cytokine productions, and mRNA expression in the presence of OVA in vitro. Results Crude extracts of leaves of N. hiiranensis significantly inhibited IL-12, IFN-γ, and IL-2 cytokine productions as well as the serum levels of antigen-specific IgM and IgG2a in vivo. Two of fourteen selected terpenoids and one diterpenoid derived from the leaves of N. hiiranensis suppressed IFN-γ in vitro. In addition, β-caryophyllene oxide attenuated the expression of IFN-γ, T-bet, and IL-12Rβ2 in a dose-dependent manner. N. hiiranensis-derived β-caryophyllene oxide inhibited several aspects of adaptive immune responses, including T-cell differentiation, IFN-γ production, and Th1-assocaited genes. Conclusion As IFN-γ is the key cytokine secreted by T helper-1 cells and plays a pivotal role in Th1 immune responses, our results suggested that the N. hiiranensis and its terpenoids may possess potential therapeutic effects on Th1-mediated immune disorders.

Adaptive immunity

2020 ◽  
pp. 325-336
Author(s):  
Paul Klenerman
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Adaptive Immunity ◽  
Innate Immune Response ◽  
Molecular Basis ◽  
Adaptive Immune Response ◽  
Antigenic Specificity ◽  
Adaptive Immune Responses ◽  
Research Attention ◽  
Adaptive Immune

The adaptive immune response is distinguished from the innate immune response by two main features: its capacity to respond flexibly to new, previously unencountered antigens (antigenic specificity), and its enhanced capacity to respond to previously encountered antigens (immunological memory). These two features have provided the focus for much research attention, from the time of Jenner, through Pasteur onwards. Historically, innate and adaptive immune responses have often been treated as separate, with the latter being considered more ‘advanced’ because of its flexibility. It is now clear this not the case, and in recent years the molecular basis for these phenomena has become much better understood.

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