scholarly journals Serine esterase and hemolytic activity in human cloned cytotoxic T lymphocytes.

1988 ◽  
Vol 167 (2) ◽  
pp. 528-540 ◽  
Author(s):  
W S Ferguson ◽  
C R Verret ◽  
E B Reilly ◽  
M J Iannini ◽  
H N Eisen
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Hemolytic Activity ◽  
Active Sites ◽  
Blot Hybridization ◽  
Target Cells ◽  
Serine Esterase ◽  
Dot Blot ◽  
Ph Optimum

Target cell lysis by most murine cytotoxic T lymphocytes appears to be mediated by a complement (C9)-like protein called perforin, contained in high-density cytoplasmic granules. These granules also contain high levels of serine esterase activity, which may also play a role in cytolysis. Analysis of 17 cloned human cytotoxic T lymphocytes revealed the presence of serine esterase that is very similar to its murine counterpart in substrate and inhibitor specificities, pH optimum, and molecular mass; dot blot hybridization with synthetic oligonucleotides corresponding to the active sites of two known murine CTL esterases suggests homology to the murine enzyme HF. However, serine esterase was present at only approximately 10% of the level found in murine CTLs, and was not secreted during CTL-target cell interaction; moreover, hemolytic activity could not be detected in any of the seven cell lines tested. The results suggest that the human CTLs examined here kill their target cells by a mechanism different from that used by most cloned murine CTLs.

Target cell death triggered by cytotoxic T lymphocytes: a target cell mutant distinguishes passive pore formation and active cell suicide mechanisms

1994 ◽  
Vol 14 (1) ◽  
pp. 427-436
Author(s):  
D S Ucker ◽  
J D Wilson ◽  
L D Hebshi
Keyword(s):  
Cell Death ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Active Cell ◽  
Death Process ◽  
Target Cells ◽  
Antigenic Stimulus ◽  
Cell Suicide

The role of the target cell in its own death mediated by cytotoxic T lymphocytes (CTL) has been controversial. The ability of the pore-forming granule components of CTL to induce target cell death directly has been taken to suggest an essentially passive role for the target. This view of CTL-mediated killing ascribes to the target the single role of providing an antigenic stimulus to the CTL; this signal results in the vectoral degranulation and secretion of pore-forming elements onto the target. On the other hand, by a number of criteria, target cell death triggered by CTL appears fundamentally different from death resulting from membrane damage and osmotic lysis. CTL-triggered target cell death involves primary internal lesions of the target cell that reflect a physiological cell death process. Orderly nuclear disintegration, including lamin phosphorylation and solubilization, chromatin condensation, and genome digestion, are among the earliest events, preceding the loss of plasma membrane integrity. We have tested directly the involvement of the target cell in its own death by examining whether we could isolate mutants of target cells that have retained the ability to be recognized by and provide an antigenic stimulus to CTL while having lost the capacity to respond by dying. Here, we describe one such mutant, BW87. We have used this CTL-resistant mutant to analyze the mechanisms of CTL-triggered target cell death under a variety of conditions. The identification of a mutable target cell element essential for the cell death response to CTL provides genetic evidence that target cell death reflects an active cell suicide process similar to other physiological cell deaths.

Killing Mechanisms of Cytotoxic T Lymphocytes

Physiology ◽  
1998 ◽  
Vol 13 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Peter Groscurth ◽  
Luis Filgueira
Keyword(s):  
T Lymphocytes ◽  
Ligand Binding ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Target Cells ◽  
Receptor Ligand

Cytotoxic T lymphocytes mediate lysis of target cells by various mechanisms, including exocytosis of lytic proteins (perforin, granzymes) and receptor-ligand binding of Fas/APO molecules. Death of target cells is characterized by either necrosis or apoptosis, depending on the killing mechanism used and on the metabolism of the target cell itself.

scholarly journals Localization of aggregated cell surface antigens of target cells bound to cytotoxic T lymphocytes.

1975 ◽  
Vol 142 (4) ◽  
pp. 1011-1016 ◽  
Author(s):  
G Berke ◽  
Z V Fishelson
Keyword(s):  
T Lymphocytes ◽  
Cell Surface ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Cytotoxic T Lymphocyte ◽  
Surface Antigens ◽  
Cell Interaction ◽  
Target Cells ◽  
Cell Surface Antigens ◽  
Polar Localization

The redistribution of aggregated cell surface antigens of target cells bound to cytotoxic T lymphocytes was investigated. It was found that cap formation induced by antibody always occurred toward the site of binding. It is suggested that the polar localization of capped target cell surface determinants is a consequence of cytotoxic T-lymphocyte target cell interaction.

Cytotoxic T lymphocytes overcome Bcl-2 inhibition: target cells contribute to their own demise

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2142-2151 ◽  
Author(s):  
Ing Swie Goping ◽  
Tracy Sawchuk ◽  
Aja Rieger ◽  
Irene Shostak ◽  
R. Chris Bleackley
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Permeability Transition ◽  
Target Cells ◽  
Oxygen Species ◽  
Directed Movement ◽  
Over Expression ◽  
Cell Death Pathway ◽  
Apoptotic Activity

Cytotoxic T lymphocytes (CTLs) eliminate pathogenic cells in large part through the activity of the serine protease granzyme B (grB). However, while the apoptotic activity of grB is blocked by over-expression of Bcl-2, CTLs can still kill target cells through an ill-defined Bcl-2–independent pathway. In this report, we have identified key modulators of this Bcl-2–independent cell-death pathway, which is induced by CTLs and not purified components. Surprisingly, activation of this pathway is reliant on grB. Furthermore, this novel pathway requires mitochondrial contribution through triggering of permeability transition and generation of reactive oxygen species, yet is functional in the absence of Bax/Bak. This pathway stimulates movement of target cell mitochondria toward the point of contact with the CTLs and importantly, inhibition of this directed movement attenuates killing. Therefore, we propose that CTLs initiate a target cell response that activates multiple mitochondrial pathways. This ensures that CTLs can eliminate those target cells that have compromised apoptotic potential due to overexpression of Bcl-2.

scholarly journals Alternative Mechanisms of Respiratory Syncytial Virus Clearance in Perforin Knockout Mice Lead to Enhanced Disease

2001 ◽  
Vol 75 (20) ◽  
pp. 9918-9924 ◽  
Author(s):  
Sandra Aung ◽  
John A. Rutigliano ◽  
Barney S. Graham
Keyword(s):  
Respiratory Syncytial Virus ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Cell Lysis ◽  
Target Cells ◽  
Alternative Mechanism ◽  
Wild Type ◽  
Infected Cells ◽  
Syncytial Virus

ABSTRACT Virus-specific cytotoxic T lymphocytes are key effectors for the clearance of virus-infected cells and are required for the normal clearance of respiratory syncytial virus (RSV) in mice. Although perforin/granzyme-mediated lysis of infected cells is thought to be the major molecular mechanism used by CD8+ cytotoxic T lymphocytes for elimination of virus, its role in RSV has not been reported. Here, we show that viral clearance in perforin knockout (PKO) mice is slightly delayed but that both PKO and wild-type mice clear virus by day 10, suggesting an alternative mechanism of RSV clearance. Effector T cells from the lungs of both groups of mice were shown to lyse Fas (CD95)-overexpressing target cells in greater numbers than target cells expressing low levels of Fas, suggesting that Fas ligand (CD95L)-mediated target cell lysis was occurring in vivo. This cell lysis was associated with a delay in RSV-induced disease in PKO mice compared to the time of disease onset for wild-type controls, which correlated with increased and prolonged production of gamma interferon and tumor necrosis factor alpha levels in PKO mice. We conclude that while perforin is not necessary for the clearance of primary RSV infection, the use of alternative CTL target cell killing mechanisms is less efficient and can lead to enhanced disease.

scholarly journals Resistance of cytotoxic T lymphocytes to the lytic effects of their toxic granules.

1987 ◽  
Vol 166 (5) ◽  
pp. 1536-1547 ◽  
Author(s):  
C R Verret ◽  
A A Firmenich ◽  
D M Kranz ◽  
H N Eisen
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Cell Lines ◽  
Cytotoxic T Lymphocytes ◽  
T Lymphocyte ◽  
Target Cell ◽  
Cytotoxic T Lymphocyte ◽  
The Other ◽  
Target Cells ◽  
Resistant Cells

A cytotoxic T lymphocyte (CTL) characteristically kills target cells one after the other by releasing toxic granules that contain one or more cytolytic components. To determine how CTLs avoid destroying themselves when they release granules and lyse target cells, 7 murine CD8+ CTL cell lines were compared with 19 other cell lines for susceptibility to lysis by the isolated toxic granules. Murine CD8+ CTLs were clearly the most resistant cells: granules did not lyse them even after they were exposed to azide, cyanide, and 2-deoxyglucose, conditions that were found to enhance the susceptibility of all the other cells tested, including other T cells. Thus, resistance of CD8+ CTLs to cytotoxic granules appears to be independent of cellular ATP. To reconcile these findings with other observations that, under some circumstances, CTLs can be lysed by other CTLs, we suggest a model in which a CTL releases only a limited proportion of its toxic granules at each antigen-specific encounter with a target cell; the amount released is sufficient to kill most target cells but to leave the CTL undamaged and with enough granules to attack other target cells.

scholarly journals Target cell death triggered by cytotoxic T lymphocytes: a target cell mutant distinguishes passive pore formation and active cell suicide mechanisms.

1994 ◽  
Vol 14 (1) ◽  
pp. 427-436 ◽  
Author(s):  
D S Ucker ◽  
J D Wilson ◽  
L D Hebshi
Keyword(s):  
Cell Death ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Active Cell ◽  
Death Process ◽  
Target Cells ◽  
Antigenic Stimulus ◽  
Cell Suicide

The role of the target cell in its own death mediated by cytotoxic T lymphocytes (CTL) has been controversial. The ability of the pore-forming granule components of CTL to induce target cell death directly has been taken to suggest an essentially passive role for the target. This view of CTL-mediated killing ascribes to the target the single role of providing an antigenic stimulus to the CTL; this signal results in the vectoral degranulation and secretion of pore-forming elements onto the target. On the other hand, by a number of criteria, target cell death triggered by CTL appears fundamentally different from death resulting from membrane damage and osmotic lysis. CTL-triggered target cell death involves primary internal lesions of the target cell that reflect a physiological cell death process. Orderly nuclear disintegration, including lamin phosphorylation and solubilization, chromatin condensation, and genome digestion, are among the earliest events, preceding the loss of plasma membrane integrity. We have tested directly the involvement of the target cell in its own death by examining whether we could isolate mutants of target cells that have retained the ability to be recognized by and provide an antigenic stimulus to CTL while having lost the capacity to respond by dying. Here, we describe one such mutant, BW87. We have used this CTL-resistant mutant to analyze the mechanisms of CTL-triggered target cell death under a variety of conditions. The identification of a mutable target cell element essential for the cell death response to CTL provides genetic evidence that target cell death reflects an active cell suicide process similar to other physiological cell deaths.

scholarly journals Interfacial actin protrusions mechanically potentiate killing by cytotoxic T cells

2018 ◽  
Author(s):  
Fella Tamzalit ◽  
Mitchell S. Wang ◽  
Weiyang Jin ◽  
Vitaly Boyko ◽  
John M. Heddleston ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Immune Cell ◽  
Immunological Synapse ◽  
Cytotoxic T Cells ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Target Cells ◽  
Immunological Synapses

ABSTRACTCytotoxic T lymphocytes (CTLs) kill by forming immunological synapses with target cells and secreting toxic proteases and the pore forming protein perforin into the intercellular space. Immunological synapses are highly dynamic structures that potentiate perforin activity by applying mechanical force against the target cell. Here, we employed high-resolution imaging and microfabrication to investigate how CTLs exert synaptic forces and coordinate their mechanical output with perforin secretion. Using micropatterned stimulatory substrates that enable synapse growth in three dimensions, we found that perforin release occurs at the base of actin-rich protrusions that extend from central and intermediate locations within the synapse. These protrusions, which depended on the cytoskeletal regulator WASP and the Arp2/3 actin nucleation complex, were required for synaptic force exertion and efficient killing. They also mediated physical distortion of the target cell surface during CTL-target cell interactions. Our results reveal the mechanical basis of cellular cytotoxicity and highlight the functional importance of dynamic, three-dimensional architecture in immune cell-cell interfaces.One sentence summaryCytotoxic T lymphocytes use F-actin-rich protrusions at the immunological synapse to potentiate perforin-and granzyme-mediated target cell killing.

scholarly journals Unexpected cell surface labeling in conjugates between cytotoxic T lymphocytes and target cells.

1985 ◽  
Vol 33 (7) ◽  
pp. 647-654 ◽  
Author(s):  
C Foa ◽  
P Bongrand ◽  
J R Galindo ◽  
P Golstein
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell ◽  
Present Report ◽  
Class I ◽  
Target Cells ◽  
Major Histocompatibility ◽  
Histocompatibility Antigens ◽  
Cell Class ◽  
Major Histocompatibility Antigens

Specific binding of target cells by cytotoxic T lymphocytes (CTL) is an example of tight interaction between two different cell types. The molecular events that occur at the cell membranes during these interactions are largely unknown. In the present report, we describe an electron microscopic immunostaining study made on CTL-target cell conjugates. Various membrane structures were labeled with monoclonal antibodies specific for structures possibly relevant to cytolysis (Lyt-2, LFA-1, and target cell class I major histocompatibility antigens) or probably unrelated to the cytolytic process (effector cell class I major histocompatibility antigens). Antibodies against Thy-1 were also used. Staining was achieved with immunoperoxidase or immunoferritin. With both techniques nonconjugated cells were either stained or not, depending on whether they bore the antigen corresponding to the antibody used. However, when conjugated to an antigen-bearing cell, a "non-antigen bearing" cell was labeled near the cell interaction area. No increased Fc receptor activity could be detected on bound cells near the interaction area. These data are consistent with the occurrence of limited exchange of membrane macromolecules between bound CTL and target cell.

Fas-mediated Lysis of Target Cell by IL-2 Treated Cytotoxic T Lymphocytes.

2002 ◽  
Vol 49 (3) ◽  
pp. 119-129 ◽  
Author(s):  
AKIRA AKASHI ◽  
KOICHI KUWANO
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Target Cell
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