scholarly journals Lipid order and charge protect killer T cells from accidental death

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jesse A. Rudd-Schmidt ◽  
Adrian W. Hodel ◽  
Tahereh Noori ◽  
Jamie A. Lopez ◽  
Hyun-Jung Cho ◽  
...  
Keyword(s):  
T Cells ◽  
Plasma Membrane ◽  
Target Cell ◽  
Serine Proteases ◽  
Immunological Synapse ◽  
Synaptic Cleft ◽  
Target Cells ◽  
Lipid Order ◽  
Target Cell Membrane ◽  
Killer T Cells

AbstractKiller T cells (cytotoxic T lymphocytes, CTLs) maintain immune homoeostasis by eliminating virus-infected and cancerous cells. CTLs achieve this by forming an immunological synapse with their targets and secreting a pore-forming protein (perforin) and pro-apoptotic serine proteases (granzymes) into the synaptic cleft. Although the CTL and the target cell are both exposed to perforin within the synapse, only the target cell membrane is disrupted, while the CTL is invariably spared. How CTLs escape unscathed remains a mystery. Here, we report that CTLs achieve this via two protective properties of their plasma membrane within the synapse: high lipid order repels perforin and, in addition, exposed phosphatidylserine sequesters and inactivates perforin. The resulting resistance of CTLs to perforin explains their ability to kill target cells in rapid succession and to survive these encounters. Furthermore, these mechanisms imply an unsuspected role for plasma membrane organization in protecting cells from immune attack.

scholarly journals High plasma membrane lipid order imaged at the immunological synapse periphery in live T cells

2010 ◽  
Vol 27 (4-6) ◽  
pp. 178-189 ◽  
Author(s):  
Dylan M. Owen ◽  
Stephane Oddos ◽  
Sunil Kumar ◽  
Daniel M. Davis ◽  
Mark A. A. Neil ◽  
...  
Keyword(s):  
T Cells ◽  
Plasma Membrane ◽  
Immunological Synapse ◽  
High Plasma ◽  
Membrane Lipid ◽  
Lipid Order ◽  
Plasma Membrane Lipid

scholarly journals Participation of the H-2 antigens of tumor cells in their lysis by syngeneic T cells.

1976 ◽  
Vol 143 (3) ◽  
pp. 601-614 ◽  
Author(s):  
J W Schrader ◽  
G M Edelman
Keyword(s):  
T Cells ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Target Cell ◽  
Cytotoxic T Cells ◽  
Hybrid Origin ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Effector Cells

Cytotoxic T lymphocytes were generated in vitro against H-2 compatible or syngeneic tumor cells. In vitro cytotoxic activity was inhibited by specific anti-H2 sera, suggesting that H-2 antigens are involved in cell lysis. Two observations directly demonstrated the participation of the H-2 antigens on the tumor cells in their lysis by H-2-compatible T cells. First, coating of the H-2 antigens on the target tumor cell reduced the number of cells lysed on subsequent exposure to cytotoxic T cells. Second, when cytotoxic T cells were activated against an H-2 compatible tumor and assayed against an H-2-incompatible tumor, anti-H-2 serum that could bind to the target cell, but not to the cytotoxic lymphocyte, inhibited lysis. H-2 antigens were also shown to be present on the cytotoxic lymphocytes. Specific antisera reacting with these H-2 antigens, but not those of the target cell, failed to inhibit lysis when small numbers of effector cells were assayed against H-2-incompatible target cells or when effector cells of F1-hybrid origin and bearing two H-2 haplotypes were assayed against a tumor cell of one of the parental strains. These findings suggest that it is the H-2 antigens on the tumor cell and not those on the cytotoxic lymphocytes that are important in cell-mediated lysis of H-2-compatible tumor cells.

scholarly journals Recognition of virus-infected cells by natural killer cell clones is controlled by polymorphic target cell elements.

1993 ◽  
Vol 178 (3) ◽  
pp. 961-969 ◽  
Author(s):  
M S Malnati ◽  
P Lusso ◽  
E Ciccone ◽  
A Moretta ◽  
L Moretta ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Target Cell ◽  
Nk Cell ◽  
Class I ◽  
Target Cells ◽  
Cell Recognition ◽  
Infected Cells ◽  
Nk Cell Recognition

Natural killer (NK) cells provide a first line of defense against viral infections. The mechanisms by which NK cells recognize and eliminate infected cells are still largely unknown. To test whether target cell elements contribute to NK cell recognition of virus-infected cells, human NK cells were cloned from two unrelated donors and assayed for their ability to kill normal autologous or allogeneic cells before and after infection by human herpesvirus 6 (HHV-6), a T-lymphotropic herpesvirus. Of 132 NK clones isolated from donor 1, all displayed strong cytolytic activity against the NK-sensitive cell line K562, none killed uninfected autologous T cells, and 65 (49%) killed autologous T cells infected with HHV-6. A panel of representative NK clones from donors 1 and 2 was tested on targets obtained from four donors. A wide heterogeneity was observed in the specificity of lysis of infected target cells among the NK clones. Some clones killed none, some killed only one, and others killed more than one of the different HHV-6-infected target cells. Killing of infected targets was not due to complete absence of class I molecules because class I surface levels were only partially affected by HHV-6 infection. Thus, target cell recognition is not controlled by the effector NK cell alone, but also by polymorphic elements on the target cell that restrict NK cell recognition. Furthermore, NK clones from different donors display a variable range of specificities in their recognition of infected target cells.

scholarly journals Induction of specific immune unresponsiveness with purified mixed leukocyte culture-activated T lymphoblasts as autoimmunogen. III. Proof for the existence of autoanti-idiotypic killer T cells and transfer of suppression to normal syngeneic recipients by T or B lymphocytes.

1978 ◽  
Vol 147 (1) ◽  
pp. 63-76 ◽  
Author(s):  
H Binz ◽  
H Wigzell
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Underlying Mechanism ◽  
Lymphoid Cells ◽  
Target Cells ◽  
Selective Suppression ◽  
Specific Receptors ◽  
T Lymphoblasts ◽  
Killer T Cells ◽  
Suppressive Mechanism

Specific immune unresponsiveness against a given set of histocompatibility antigens can be induced by immunization with autologous, antigen-specific T lymphoblasts. Such unresponsiveness can be transferred by lymphoid cells from autoblast-immunized donors to normal syngeneic recipients. The cells being most efficient in transferring the selective suppression are T lymphocytes from the spleen, especially if of Ly 1-2+3+ phenotype. By using such T lymphocytes we deem it likely that the actual underlying mechanism is one of actual transfer of autoanti-idiotypic killer T cells. In support for this view is the fact that such T cells endowed with exquisite specific, cytolytic reactivity towards autologous idiotype-positive T target cells exist in autoblast immune animals. Significant suppression may also be transferred with T cells of Ly 1+2-3- phenotype or with B cells. Here, we consider the suppressive mechanism to be one of production of autoanti-idiotypic antibodies. By using affinity fraction procedures, it was finally possible to prove that all T-cell suppressive activity resides in a population with true antigen-binding-specific receptors for the relevant idiotypes.

scholarly journals Calcium ion concentrations and DNA fragmentation in target cell destruction by murine cloned cytotoxic T lymphocytes.

1988 ◽  
Vol 167 (2) ◽  
pp. 514-527 ◽  
Author(s):  
N L Allbritton ◽  
C R Verret ◽  
R C Wolley ◽  
H N Eisen
Keyword(s):  
Dna Fragmentation ◽  
Target Cell ◽  
Target Cells ◽  
Pronounced Increase ◽  
Ion Concentrations ◽  
Emission Maximum ◽  
Cytolytic Granule ◽  
Target Cell Membrane ◽  
Membrane Changes ◽  
High Level

To investigate the destruction of target cells by murine CTLs, we examined intracellular Ca2+ concentrations ([Ca2+]i) and DNA fragmentation in target cells. Changes in [Ca2+]i were followed by flow cytometry by loading the cells with indo-1, a Ca2+-binding fluorescent dye, and determining the ration of fluorescence intensities at 405 nm (emission maximum for Ca2+-bound dye) over 480 nm (emission maximum for the free dye). Within minutes after interacting with the cytolytic granule fraction that had been isolated from CTLs, [Ca2+]i in target cells was strikingly increased. A pronounced increase in [Ca2+]i was also observed in target cells when they were specifically recognized by intact CTLs. Since ionomycin, a Ca2+ ionophore, caused a similar increase in [Ca2+]i and lysed cells (provided that extracellular Ca2+ was present), it appears that a sustained high level of [Ca2+]i is cytolytic. In contrast with other cells, CTLs, which have been shown to be refractory to granule-mediated lysis and to be poor targets for other CTLs, did not manifest an elevation in [Ca2+]i when they were similarly loaded with indo-1 and treated with isolated granules. The characteristic cleavage of target cell DNA into nucleosome-sized fragments was also induced by isolated granules as well as by valinomycin, a K+ ionophore, but not by ionomycin. The results support the view that lysis of most target cells by cloned CTLs is due primarily to target cell membrane changes that are fundamentally equivalent to the formation of nonspecific ion channels. The resulting large increase in [Ca2+]i is probably responsible for target cell lysis; and changes in intracellular ion concentrations also appear to be responsible for DNA fragmentation, probably by activating endogenous target cell endonucleases.

scholarly journals NOVEL IMMUNOTHERAPEUTIC TARGETED GRANZYME DELIVERY SYSTEMS IN TREATMENT OF MALIGNANT TUMORS

2021 ◽  
Vol 20 (2) ◽  
pp. 31-41
Author(s):  
I. V. Yarosh ◽  
V. A. Misyurin ◽  
I. I. Krasnyuk
Keyword(s):  
Cell Death ◽  
Target Cell ◽  
Serine Proteases ◽  
Malignant Tumors ◽  
Granzyme B ◽  
Killer Cell ◽  
Cascade Reactions ◽  
Target Cells ◽  
Cell Property ◽  
Infected Cells

Cytotoxicity is the main human killer cell property. The cytotoxicity reaction of human killer cells is achieved through a complex of molecules, including perforins, granzyme, cathepsin and others. However, only one molecule is enough for target cell death: granzyme. Other molecules are intended for granzyme activation and its delivery to the target cell cytoplasm. Granzymes are a whole family of serine proteases that perform their function in the human body as integral cytolytic effectors during programmed cell death of cancer and pathogen-infected cells. Secreted mainly by cytotoxic T-lymphocytes and NK-cells, granzymes initiate apoptosis via caspase-dependent and caspase-independent pathways. These natural properties make granzymes one of the most promising human enzymes for use in the development of targeted therapeutic strategies in the treatment of various types of cancer.The most promising is granzyme B, because it has the most powerful effector properties. Due to the initiation of cascade reactions that activate apoptosis, granzyme is attractive as a basis for the development of medicines applicable in clinical oncology. At this time, several approaches have been developed for delivering granzyme molecules to tumor cells and facilitating its penetration through the cell membrane. Moreover, some solutions are proposed to overcome the resistance of target cells to granzyme-mediated apoptosis. These approaches are discussed in this review.The purpose of this review was to systematize information on the use of granzyme B as a nanostructured drug delivery system in the treatment of solid and hematological malignancies. In addition, this review discusses ways to overcome the resistance of granzyme penetration into target cells.

Activation of T Cells by Bispecific Single-Chain Construct MT103 (MEDI-538) Is Strictly Target Cell-Dependent.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3889-3889
Author(s):  
Klaus Brischwein ◽  
Scott A. Hammond ◽  
Larissa Parr ◽  
Schlereth Bernd ◽  
Mathias Locher ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Target Cell ◽  
Cell Activation ◽  
Cell Lysis ◽  
Target Cells ◽  
Single Chain ◽  
Activation Markers ◽  
Human T Cells

Abstract Background: Bispecific antibodies have been extensively studied in vitro and in vivo for their use in redirected tumor cell lysis. A particular challenge of bispecific antibody constructs recognizing the CD3 signaling complex is to achieve a controlled polyclonal activation of T-cells that, ideally, is entirely dependent on the presence of target cells. If this is not the case, systemic production of inflammatory cytokines and secondary endothelial reactions may occur as side effects, as are observed with the murine anti-human CD3e antibody OKT-3 (muromab, Orthoclone®). Here we present evidence that MT103 (or MEDI-538), a bispecific single chain antibody of the BiTE class that targets CD19 and CD3, induces T-cell activation exclusively in the presence of target cells. Material and methods: Peripheral blood mononuclear cells from healthy donors were prepared by Ficoll density centrifugation. PBMC were incubated for 24 hours with MT103 in presence or absence of specific target cells. Target cell lysis was determined by measurement of adenylate kinase activity released from lysed cells. De novo expression of activation markers CD69 and CD25 on T-cells was assessed by flow cytometry using directly conjugated monoclonal antibodies, and the concentration of cytokines in the supernatant was determined by a commercial FACS-based bead array. Results: MT103 was analyzed for conditional T-cell activation. In the presence of target-expressing cell lines, low picomolar concentrations of MT103 were sufficient to stimulate a high percentage of peripheral human T-cells to express cytokines and surface activation markers, to enter into the cell cycle and to induce redirected lysis of target cells. However, in the absence of target cells, the BiTE molecules no longer detectably activated human T-cells even at concentrations exceeding the ED50 for redirected lysis and conditional T-cell activation by more than five orders of magnitude. Conclusion: Our data show that T-cell activation by MT103 is highly conditional in that it is strictly dependent on the presence.

New CFSE-based assay to determine susceptibility to lysis by cytotoxic T cells of leukemic precursor cells within a heterogeneous target cell population

Blood ◽  
2004 ◽  
Vol 103 (7) ◽  
pp. 2677-2682 ◽  
Author(s):  
Inge Jedema ◽  
Nicole M. van der Werff ◽  
Renée M. Y. Barge ◽  
Roel Willemze ◽  
J. H. Frederik Falkenburg
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Cell Population ◽  
Target Cell ◽  
Precursor Cells ◽  
Leukemic Cells ◽  
Cell Populations ◽  
Target Cells ◽  
Specific Cell

Abstract For the clinical evaluation of the efficacy of cellular immunotherapy it is necessary to analyze the effector functions of T cells against primary leukemic target cell populations which are usually considerably heterogeneous caused by differential maturation stages of the leukemic cells. An appropriate assay should not only allow the quantitative analysis of rapid cell death induction as measured by the conventional 51Cr release assay but also of the more slowly executing pathways of T-cell-induced apoptosis occurring within days instead of hours which cannot be measured using this method. Furthermore, it should dissect the differential susceptibility to T-cell-induced cell death of various target cell subpopulations and characterize the malignant precursor cells capable of producing malignant progeny. To fulfill these requirements we developed a new assay based on carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling of the target cell population combined with antibody staining of specific cell populations and addition of fluorescent microbeads to quantitatively monitor target cell death occurring within a longer time frame up to at least 5 days. This new assay facilitates the analysis of differential recognition of distinct cell types within a heterogeneous target cell population and allows simultaneously evaluation of the proliferative status of surviving target cells in response to relevant cytokines. (Blood. 2004;103: 2677-2682)

scholarly journals Specific targeting of human peripheral blood T cells by heteroaggregates containing anti-T3 crosslinked to anti-target cell antibodies.

1986 ◽  
Vol 163 (1) ◽  
pp. 166-178 ◽  
Author(s):  
P Perez ◽  
R W Hoffman ◽  
J A Titus ◽  
D M Segal
Keyword(s):  
T Cells ◽  
Target Cell ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Target Cells ◽  
Ifn Gamma ◽  
Effector Cells ◽  
Infected Cells ◽  
Covalently Linked

Antibody heteroaggregates have been used to render human peripheral blood T cells lytic for specified targets. The heteroaggregates contain anti-T3 covalently linked to antibodies against nominal target cell antigens. Such heteroaggregates bind target cells directly to T3 molecules on effector cells and trigger target cell lysis. Freshly prepared human PBL, when coated with anti-T3-containing heteroaggregates, are lytic without further stimulation, although brief exposure to crude lymphokine-containing supernatants or recombinant IL-2, but not recombinant IFN-gamma, enhances the activity. The effector cells are T8+, and when fully stimulated, their lytic activity approaches that of some cloned CTL. When T cells are treated with heteroaggregate, washed, and incubated at 37 degrees C in medium not containing heteroaggregate, they retain activity for at least 24 h. The results of this study suggest a strategy in which heteroaggregate-coated T cells could be used in vivo to mount a lytic response against pathogenic cells such as tumor cells or virus-infected cells.

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