memory t cells
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2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Rhia Kundu ◽  
Janakan Sam Narean ◽  
Lulu Wang ◽  
Joseph Fenn ◽  
Timesh Pillay ◽  
...  

AbstractCross-reactive immune responses to SARS-CoV-2 have been observed in pre-pandemic cohorts and proposed to contribute to host protection. Here we assess 52 COVID-19 household contacts to capture immune responses at the earliest timepoints after SARS-CoV-2 exposure. Using a dual cytokine FLISpot assay on peripheral blood mononuclear cells, we enumerate the frequency of T cells specific for spike, nucleocapsid, membrane, envelope and ORF1 SARS-CoV-2 epitopes that cross-react with human endemic coronaviruses. We observe higher frequencies of cross-reactive (p = 0.0139), and nucleocapsid-specific (p = 0.0355) IL-2-secreting memory T cells in contacts who remained PCR-negative despite exposure (n = 26), when compared with those who convert to PCR-positive (n = 26); no significant difference in the frequency of responses to spike is observed, hinting at a limited protective function of spike-cross-reactive T cells. Our results are thus consistent with pre-existing non-spike cross-reactive memory T cells protecting SARS-CoV-2-naïve contacts from infection, thereby supporting the inclusion of non-spike antigens in second-generation vaccines.


Author(s):  
Jianfang Ning ◽  
Noah V. Gavil ◽  
Shaoping Wu ◽  
Sathi Wijeyesinghe ◽  
Eyob Weyu ◽  
...  

2022 ◽  
Vol 10 (1) ◽  
pp. 166-176
Author(s):  
Yun Wu ◽  
Guo-Jiang Wang ◽  
Hui-Qiong He ◽  
Hai-Hong Qin ◽  
Wen-Tong Shen ◽  
...  

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262455
Author(s):  
Takuya Mori ◽  
Hiroaki Tanaka ◽  
Sota Deguchi ◽  
Yoshihito Yamakoshi ◽  
Yuichiro Miki ◽  
...  

Nivolumab, an immune checkpoint blocker, has been approved for advanced gastric cancer (GC), but predictive factors of nivolumab’s efficacy in patients with GC, especially immune cells such as tissue-resident memory T cells or those forming tertiary lymphoid structures (TLS), remain unclear. Tissue samples were obtained from surgically resected specimens of patients with GC who were treated with nivolumab as third-line or later treatment. Immunohistochemical staining was performed to detect the presence of TLS and CD103+ T cells and assess the association between TLSs and response to nivolumab treatment. A total of 19 patients were analyzed. In patients with partial response (PR) to nivolumab, numerous TLS were observed, and CD103+ T cells were found in and around TLS. Patients with many TLS experienced immune-related adverse events more often than those with few TLS (p = 0.018). The prognosis of patients with TLS high was better than those with TLS low. Patients with a combination of TLS high and CD103 high tended to have a better prognosis than other groups. Our results suggested that TLS status might be a predictor of nivolumab effectiveness.


2022 ◽  
Vol 12 ◽  
Author(s):  
Xu Li ◽  
Manik Garg ◽  
Tingting Jia ◽  
Qijun Liao ◽  
Lifang Yuan ◽  
...  

Despite many studies on the immune characteristics of Coronavirus disease 2019 (COVID-19) patients in the progression stage, a detailed understanding of pertinent immune cells in recovered patients is lacking. We performed single-cell RNA sequencing on samples from recovered COVID-19 patients and healthy controls. We created a comprehensive immune landscape with more than 260,000 peripheral blood mononuclear cells (PBMCs) from 41 samples by integrating our dataset with previously reported datasets, which included samples collected between 27 and 47 days after symptom onset. According to our large-scale single-cell analysis, recovered patients, who had severe symptoms (severe/critical recovered), still exhibited peripheral immune disorders 1–2 months after symptom onset. Specifically, in these severe/critical recovered patients, human leukocyte antigen (HLA) class II and antigen processing pathways were downregulated in both CD14 monocytes and dendritic cells compared to healthy controls, while the proportion of CD14 monocytes increased. These may lead to the downregulation of T-cell differentiation pathways in memory T cells. However, in the mild/moderate recovered patients, the proportion of plasmacytoid dendritic cells increased compared to healthy controls, accompanied by the upregulation of HLA-DRA and HLA-DRB1 in both CD14 monocytes and dendritic cells. In addition, T-cell differentiation regulation and memory T cell–related genes FOS, JUN, CD69, CXCR4, and CD83 were upregulated in the mild/moderate recovered patients. Further, the immunoglobulin heavy chain V3-21 (IGHV3-21) gene segment was preferred in B-cell immune repertoires in severe/critical recovered patients. Collectively, we provide a large-scale single-cell atlas of the peripheral immune response in recovered COVID-19 patients.


2022 ◽  
pp. 112614
Author(s):  
Sepideh Zununi Vahed ◽  
Seyed Mahdi Hosseiniyan Khatibi ◽  
Elham Ahmadian ◽  
Mohammadreza Ardalan

Author(s):  
Ying Xia ◽  
Aqing Liu ◽  
Wentao Li ◽  
Yunhe Liu ◽  
Guan Zhang ◽  
...  

Abstract Naïve T and T memory cell subsets are closely related to immune response and can provide important information for the diagnosis and treatment of immunological and hematological disorders. Lymphocyte compartment undergo dramatic changes during adulthood; age-related reference values derived from healthy individuals are crucial. However, extensively detailed reference values of peripheral blood lymphocytes in whole spectrum of adulthood detected by multi-color flow cytometry on a single platform are rare. 309 healthy adult volunteers were recruited from Tianjin in China. The absolute counts and percentages of CD3+CD4+ T cells, CD3+CD8+ T cells, naïve T cells (Tn), T memory stem cells (Tscm), central memory T cells (Tcm), effector memory T cells (Tem), terminal effector T cells (Tte) were detected by flow cytometry with single platform technologies. Reference range of absolute counts and percentage of T lymphocyte subsets were formulated by different age and gender. The results showed that Tn and Tscm cells, which had stem cell properties, decreased with aging; while, Tcm and Tem increased with aging, which increased from 18 to 64 years old but presented no significant change over the 65 years old. Gender had influence on the fluctuation of lymphocyte subsets, absolute count of CD3+CD8+, CD8+ Tcm, CD8+ Tem in male were higher than those in female. The reference values of percentages and absolute numbers of naïve T and T memory cell subsets can help doctors to understand the immune state of patients and evaluate conditions of prognosis then adjust treatment for patients.


2021 ◽  
Vol 23 (6) ◽  
pp. 1229-1238
Author(s):  
I. A. Ivanova ◽  
N. D. Omelchenko ◽  
A. V. Filippenko ◽  
A. A. Trufanova ◽  
A. K. Noskov

The data obtained during previous epidemics caused by coronaviruses, and current pandemic indicate that assessing the role of certain immune interactions between these viruses and the microorganism is the main pre-requisite for development of diagnostic test systems as well as effective medical drugs and preventive measures. The review summarizes the results of studying patho– and immunogenesis of SARSCoV, MERS-CoV, and SARS-CoV-2 infections. These coronaviruses were proven to suppress development of adaptive immune response at the stage of its induction, affecting the number and functional activity of lymphocytes, effectors of cellular immunity, causing impairment of lymphopoiesis, apoptosis and «depletion» of these cells, thus leading to longer duration of the disease and increased viral load. Information about the role of cellular immunity in development of immune response to coronaviruses is presented. It was proven that the causative agents of SARS, MERS and COVID-19 trigger adaptive immune response in the microorganism according to both humoral and cellular types. Moreover, the synthesis of specific immunoglobulins does not yet point to presence of protective immune response. Activation of the cellular link of immunity is also important. A high degree of antigenic epitope homology in SARS-CoV, MERS-CoV and SARS-CoV-2 is described, thus suggesting an opportunity for cross-immunity to coronaviruses. The review addresses issues related to the terms of specific memory immune cells to SARS-CoV, MERS-CoV and SARS-CoV-2, and their role in providing long-term protection against these infections. Given that specific antibodies to SARS and MERS pathogens persisted for a year, were often not detected or briefly registered in patients with mild and asymptomatic infections, we can talk about important role of the cellular immune response in providing immunity to these coronaviruses. It was shown that, in contrast to antibodies, the antigen-specific memory T cells were registered in patients with SARS virus for 4 to 11 years, and Middle East Respiratory Syndrome – up to two years. Further research is needed to determine presence and number of memory T cells in COVID-19. A comparative analysis of data obtained during previous epidemics with respect to formation of adaptive immunity to coronaviruses. Description of proteins and epitopes recognized by human T lymphocytes will be useful in monitoring immune responses in COVID-19 patients, as well as in developing informative tests to study T cell immune response to SARS-CoV-2 and new preventive drugs.


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