scholarly journals NK cells promote transplant tolerance by killing donor antigen-presenting cells

2006 ◽  
Vol 203 (8) ◽  
pp. 1851-1858 ◽  
Author(s):  
Guang Yu ◽  
Xuemin Xu ◽  
Minh Diem Vu ◽  
Elizabeth D. Kilpatrick ◽  
Xian Chang Li
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Tolerance Induction ◽  
Antigen Presenting Cells ◽  
Cell Types ◽  
Target Cells ◽  
Skin Allograft ◽  
Transplant Tolerance ◽  
Skin Allografts ◽  
Antigen Presenting

Natural killer (NK) cells are programmed to kill target cells without prior antigen priming. Because of their potent cytolytic activities, NK cells are one of the key cell types involved in dismantling allografts. However, in certain transplant models, NK cells also express potent immunoregulatory properties that promote tolerance induction. The precise mechanism for such striking dichotomy remains unknown. In the present study, we showed in a skin transplant model that the skin allografts contain a subset of antigen-presenting cells (APCs) that can home to the recipient mice. We also showed that such graft-derived APCs are usually destroyed by the host NK cells. But in the absence of NK cells, donor APCs can survive and then migrate to the host lymphoid and extralymphoid sites where they directly stimulate the activation of alloreactive T cells. T cells activated in the absence of NK cells are more resistant to costimulatory blockade treatment, and under such conditions stable skin allograft survival is difficult to achieve. Our study identified a novel role for NK cells in regulating T cell priming in transplant models, and may have important clinical implications in tolerance induction.

Adhesion of human T cells to antigen-presenting cells through SIRPβ2-CD47 interaction costimulates T-cell proliferation

Blood ◽  
2005 ◽  
Vol 105 (6) ◽  
pp. 2421-2427 ◽  
Author(s):  
Laura Piccio ◽  
William Vermi ◽  
Kent S. Boles ◽  
Anja Fuchs ◽  
Carey A. Strader ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Antigen Presenting Cells ◽  
Cell Types ◽  
Orphan Receptor ◽  
T Cell Proliferation ◽  
Central Nervous Systems ◽  
And Function ◽  
Antigen Presenting

AbstractSignal-regulatory proteins (SIRPs) are transmembrane glycoproteins belonging to the immunoglobulin (Ig) superfamily that are expressed in the immune and central nervous systems. SIRPα binds CD47 and inhibits the function of macrophages, dendritic cells, and granulocytes, whereas SIRPβ1 is an orphan receptor that activates the same cell types. A recently identified third member of the SIRP family, SIRPβ2, is as yet uncharacterized in terms of expression, specificity, and function. Here, we show that SIRPβ2 is expressed on T cells and activated natural killer (NK) cells and, like SIRPα, binds CD47, mediating cell-cell adhesion. Consequently, engagement of SIRPβ2 on T cells by CD47 on antigen-presenting cells results in enhanced antigen-specific T-cell proliferation.

HLA‐G up‐regulates ILT2, ILT3, ILT4, and KIR2DL4 in antigen presenting cells, NK cells, and T cells

2005 ◽  
Vol 19 (6) ◽  
pp. 1-23 ◽  
Author(s):  
Joël Lemaoult ◽  
Kamélia Zafaranloo ◽  
Caroline Le Danff ◽  
Edgardo D. Carosella
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Antigen Presenting Cells ◽  
Antigen Presenting

scholarly journals Interleukin-12–Activated Natural Killer Cells Recognize B7 Costimulatory Molecules on Tumor Cells and Autologous Dendritic Cells

Blood ◽  
1998 ◽  
Vol 91 (1) ◽  
pp. 196-206 ◽  
Author(s):  
Anja B. Geldhof ◽  
Muriel Moser ◽  
Laurence Lespagnard ◽  
Kris Thielemans ◽  
Patrick De Baetselier
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Tumor Cells ◽  
Synergistic Effects ◽  
Antigen Presenting Cells ◽  
Interleukin 12 ◽  
Target Cells ◽  
Effector Cells ◽  
Antigen Presenting

Activation of natural killer (NK) cells in the presence of interleukin-12 (IL-12) augments the capacity of these effector cells to recognize B7-1– and B7-2–expressing target cells. These effector cells also efficiently lyse autologous B7-positive progenitor or organ-derived dendritic cells, suggesting a physiologic regulatory pathway between IL-12, NK cells, and B7-expressing antigen-presenting cells. Although IL-12–activated NK cells secreted higher levels of interferon-γ, this cytokine did not play a role in synergistic effects of IL-12 and B7 on NK activation. The B7-counterreceptor was found to be selectively upregulated on IL-2/IL-12 as compared with IL-2–activated NK cells. CD28 is functionally involved in the recognition of B7 on target cells since IL-2/IL-12–activated NK cells derived from CD28 knockout mice were strongly reduced in their capacity to lyse syngeneic B7-positive tumor cells as well as antigen-presenting cells. However, recognition of B7 on allogeneic targets did not require the expression of CD28 on the IL-2/IL-12–activated NK cells. Hence, IL-12 triggers the expression of both CD28-dependent and CD28-independent mechanisms that allow NK cells to eliminate B7-positive target cells including autologous dendritic cells.

scholarly journals Interleukin-12–Activated Natural Killer Cells Recognize B7 Costimulatory Molecules on Tumor Cells and Autologous Dendritic Cells

Blood ◽  
1998 ◽  
Vol 91 (1) ◽  
pp. 196-206 ◽  
Author(s):  
Anja B. Geldhof ◽  
Muriel Moser ◽  
Laurence Lespagnard ◽  
Kris Thielemans ◽  
Patrick De Baetselier
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Tumor Cells ◽  
Synergistic Effects ◽  
Antigen Presenting Cells ◽  
Interleukin 12 ◽  
Target Cells ◽  
Effector Cells ◽  
Antigen Presenting

Abstract Activation of natural killer (NK) cells in the presence of interleukin-12 (IL-12) augments the capacity of these effector cells to recognize B7-1– and B7-2–expressing target cells. These effector cells also efficiently lyse autologous B7-positive progenitor or organ-derived dendritic cells, suggesting a physiologic regulatory pathway between IL-12, NK cells, and B7-expressing antigen-presenting cells. Although IL-12–activated NK cells secreted higher levels of interferon-γ, this cytokine did not play a role in synergistic effects of IL-12 and B7 on NK activation. The B7-counterreceptor was found to be selectively upregulated on IL-2/IL-12 as compared with IL-2–activated NK cells. CD28 is functionally involved in the recognition of B7 on target cells since IL-2/IL-12–activated NK cells derived from CD28 knockout mice were strongly reduced in their capacity to lyse syngeneic B7-positive tumor cells as well as antigen-presenting cells. However, recognition of B7 on allogeneic targets did not require the expression of CD28 on the IL-2/IL-12–activated NK cells. Hence, IL-12 triggers the expression of both CD28-dependent and CD28-independent mechanisms that allow NK cells to eliminate B7-positive target cells including autologous dendritic cells.

scholarly journals The ABCs of Antigen Presentation by Stromal Non-Professional Antigen-Presenting Cells

2021 ◽  
Vol 23 (1) ◽  
pp. 137
Author(s):  
Tom J. Harryvan ◽  
Sabine de Lange ◽  
Lukas J. A. C. Hawinkels ◽  
Els M. E. Verdegaal
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Cell Function ◽  
Antigen Presenting Cells ◽  
Cell Types ◽  
T Cell Response ◽  
Cross Presentation ◽  
Antigen Presenting

Professional antigen-presenting cells (APCs), such as dendritic cells and macrophages, are known for their ability to present exogenous antigens to T cells. However, many other cell types, including endothelial cells, fibroblasts, and lymph node stromal cells, are also capable of presenting exogenous antigens to either CD8+ or CD4+ T cells via cross-presentation or major histocompatibility complex (MHC) class II-mediated presentation, respectively. Antigen presentation by these stromal nonprofessional APCs differentially affect T cell function, depending on the type of cells that present the antigen, as well as the local (inflammatory) micro-environment. It has been recently appreciated that nonprofessional APCs can, as such, orchestrate immunity against pathogens, tumor survival, or rejection, and aid in the progression of various auto-immune pathologies. Therefore, the interest for these nonprofessional APCs is growing as they might be an important target for enhancing various immunotherapies. In this review, the different nonprofessional APCs are discussed, as well as their functional consequences on the T cell response, with a focus on immuno-oncology.

scholarly journals Inefficient exploitation of accessory receptors reduces the sensitivity of chimeric antigen receptors.

2021 ◽  
Author(s):  
Jake Burton ◽  
Jesus A Siller-Farfan ◽  
Johannes Pettmann ◽  
Benjamin Salzer ◽  
Mikhail Kutuzov ◽  
...  
Keyword(s):  
T Cells ◽  
High Sensitivity ◽  
Antigen Presenting Cells ◽  
Target Cells ◽  
Antigen Receptors ◽  
Chimeric Antigen Receptors ◽  
Adhesion Receptor ◽  
Variable Domains ◽  
Abnormal Cells ◽  
Antigen Presenting

Chimeric antigen receptors (CARs) can re-direct T cells to target abnormal cells but their activity is limited by a profound defect in antigen sensitivity, the source of which remains unclear. Here, we show that CARs have a > 100-fold lower antigen sensitivity compared to the TCR when antigen is presented on antigen-presenting-cells, but nearly identical sensitivity when antigen is presented as purified protein in isolation. Given that the TCR uses other, accessory, receptors to achieve high sensitivity, we screened prominent accessory receptors by presenting their purified ligands together with antigen. We found that ligating the adhesion receptor CD2 or LFA-1 improved antigen sensitivity for the TCR by > 100-fold, whereas for CARs the improvement was < 10-fold. We reproduced these findings using target cells where the CD2 and/or LFA-1 interaction were abrogated. Sensitivity can be partially restored by fusing the CAR variable domains to the TCR CD3ϵ subunit (also known as a TRuC) and fully restored when exchanging the TCRαβ variable domains for those of the CAR (also known as a STAR). Our study localises the defect in CAR sensitivity to inefficient use of accessory receptors and suggests approaches to increase sensitivity.

scholarly journals Identification of classical swine fever virus protein E2 as a target for cytotoxic T cells by using mRNA-transfected antigen-presenting cells

2005 ◽  
Vol 86 (9) ◽  
pp. 2525-2534 ◽  
Author(s):  
M. Ceppi ◽  
M. G. M. de Bruin ◽  
T. Seuberlich ◽  
C. Balmelli ◽  
S. Pascolo ◽  
...  
Keyword(s):  
T Cells ◽  
Classical Swine Fever Virus ◽  
Classical Swine Fever ◽  
Antigen Presenting Cells ◽  
Target Cells ◽  
Structural Protein ◽  
Ctl Epitopes ◽  
Viral Genes ◽  
Genes Encoding ◽  
Antigen Presenting

Vaccination of pigs against Classical swine fever virus (CSFV) by using live-virus vaccines induces early protection before detectable humoral immune responses. Immunological analyses indicate that this is associated with T-cell activation, underlining the importance of targeting cytotoxic T-lymphocyte (CTL) responses for vaccine improvement. Antigen-presenting cells (APCs) transfected with mRNA encoding structural protein E2 or non-structural viral proteins NS3–NS4A were used to identify viral genes encoding CTL epitopes. Monocyte-derived dendritic cells (DCs) and fibrocytes served as the APCs. In vitro translation of the mRNA and microscopic analysis of transfected cells demonstrated that E2 and NS3–NS4A could be identified. APCs transfected with either of the mRNA molecules restimulated CSFV-specific T cells to produce gamma interferon and specific cytotoxic activity against CSFV-infected target cells. The presence of CTL epitopes on E2 was confirmed by using d/d-haplotype MAX cells expressing E2 constitutively as target cells in d/d-haplotype CTL assays. A potent CTL activity against E2 was detected early (1–3 weeks) after CSFV challenge. This work corroborates the existence of CTL epitopes within the non-structural protein domain NS3–NS4A of CSFV. Furthermore, epitopes on the E2 protein can also now be classified as targets for CTLs, having important implications for vaccine design, especially subunit vaccines. As for the use of mRNA-transfected APCs, this represents a simple and efficient method to identify viral genes encoding CTL epitopes in outbred populations.

scholarly journals NK Cells and Type 1 Diabetes

2006 ◽  
Vol 13 (2-4) ◽  
pp. 101-107 ◽  
Author(s):  
Melanie Rodacki ◽  
Adolpho Milech ◽  
José Egídio Paulo de Oliveira
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Nk Cells ◽  
Target Cells ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Immune Mediated ◽  
Antigen Presenting

Type 1 diabetes (T1D) is characterized by an immuno-mediated progressive destruction of the pancreatic β cells. Due to the ability of NK cells to kill target cells as well as to interact with antigen-presenting and T cells, it has been suggested that they could be involved in one or multiple steps of the immune-mediated attack that leads to T1D. Abnormalities in the frequency and activity of NK cells have been described both in animal models and patients with T1D. Some of these alterations are linked to its onset while others seem to be a consequence of the disease. Here, we discuss the main characteristics of NK cells and review the studies that investigated the role of NK cells in T1D, both in mouse models and humans.

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