scholarly journals T-lymphocyte killing by T101-ricin A-chain immunotoxin: pH-dependent potentiation with lysosomotropic amines

Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1197-1202 ◽  
Author(s):  
P Casellas ◽  
S Ravel ◽  
BJ Bourrie ◽  
JM Derocq ◽  
FK Jansen ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Peripheral Blood Cell ◽  
T Cell Response ◽  
Ricin A Chain ◽  
Macrophage Colony ◽  
A Chain ◽  
Ricin A

Abstract To maximize T-lymphocyte killing with anti-pan-T-lymphocyte immunotoxin (IT), prepared by linking ricin A-chain to monoclonal antibody (MoAb) T101 (T101-RTA IT), we have established the nature and the extent of parameters that influence the sensitivity of T lymphocytes to the IT. We showed that peripheral blood T lymphocytes, which are much less susceptible than malignant T cells to the T101-RTA IT, could become highly sensitive to the IT when used in conjunction with NH4Cl. However, enhancement of the IT by NH4Cl only occurred when the pH rose above neutrality. This pH-sensitive process of IT activation by NH4Cl, which led to an all-or-nothing effect within an extremely narrow pH window of 0.7 pH unit width, is due to the fact that NH3 is the effective enhancing component of NH4Cl. We also showed that F(ab')2 or Fab containing IT were much more effective than those produced using the whole IgG counterpart. From these data, we defined a procedure for an optimal and specific elimination of T lymphocytes in vitro by treating them with (Fab)T101-RTA at 10(-8) mol/L at pH 7.8 in the presence of NH4Cl for two hours. This peripheral blood cell processing elicited an abrogation of three logs of functional T-cell response. Under the same conditions, there was no reduction in the number of marrow hematopoietic precursor granulocyte-macrophage colony-forming units (CFU-GM).

scholarly journals T-lymphocyte killing by T101-ricin A-chain immunotoxin: pH-dependent potentiation with lysosomotropic amines

Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1197-1202
Author(s):  
P Casellas ◽  
S Ravel ◽  
BJ Bourrie ◽  
JM Derocq ◽  
FK Jansen ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Peripheral Blood Cell ◽  
T Cell Response ◽  
Ricin A Chain ◽  
Macrophage Colony ◽  
A Chain ◽  
Ricin A

To maximize T-lymphocyte killing with anti-pan-T-lymphocyte immunotoxin (IT), prepared by linking ricin A-chain to monoclonal antibody (MoAb) T101 (T101-RTA IT), we have established the nature and the extent of parameters that influence the sensitivity of T lymphocytes to the IT. We showed that peripheral blood T lymphocytes, which are much less susceptible than malignant T cells to the T101-RTA IT, could become highly sensitive to the IT when used in conjunction with NH4Cl. However, enhancement of the IT by NH4Cl only occurred when the pH rose above neutrality. This pH-sensitive process of IT activation by NH4Cl, which led to an all-or-nothing effect within an extremely narrow pH window of 0.7 pH unit width, is due to the fact that NH3 is the effective enhancing component of NH4Cl. We also showed that F(ab')2 or Fab containing IT were much more effective than those produced using the whole IgG counterpart. From these data, we defined a procedure for an optimal and specific elimination of T lymphocytes in vitro by treating them with (Fab)T101-RTA at 10(-8) mol/L at pH 7.8 in the presence of NH4Cl for two hours. This peripheral blood cell processing elicited an abrogation of three logs of functional T-cell response. Under the same conditions, there was no reduction in the number of marrow hematopoietic precursor granulocyte-macrophage colony-forming units (CFU-GM).

scholarly journals Predicting therapeutic outcome in severe ulcerative colitis by measuring in vitro steroid sensitivity of proliferating peripheral blood lymphocytes

Gut ◽  
1999 ◽  
Vol 45 (3) ◽  
pp. 382-388 ◽  
Author(s):  
S D Hearing ◽  
M Norman ◽  
C S J Probert ◽  
N Haslam ◽  
C M Dayan
Keyword(s):  
Ulcerative Colitis ◽  
T Lymphocytes ◽  
Disease Severity ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Steroid Treatment ◽  
Steroid Resistance ◽  
Severe Ulcerative Colitis ◽  
Steroid Sensitivity

BACKGROUNDUp to 29% of patients with severe ulcerative colitis (UC) fail to respond to steroid treatment and require surgery. Previous studies have failed to show a clear correlation between failure of steroid treatment in severe UC and measures of disease severity. The reasons for treatment failure therefore remain unknown.AIMTo investigate the hypothesis that patients with severe UC who fail to respond to steroid treatment have steroid resistant T lymphocytes.METHODSEighteen patients with severe UC were studied. After seven days’ treatment with high dose intravenous steroids they were classified as complete responders (CR), incomplete responders (IR), or treatment failures (TF). Within 48 hours of admission blood was taken and the antiproliferative effect of dexamethasone on phytohaemagglutinin stimulated peripheral blood T lymphocytes was measured. Maximum dexamethasone induced inhibition of proliferation (Imax) was measured.RESULTSIn vitro T lymphocyte steroid sensitivity of TF and IR patients was significantly less than that of CR patients. Both TF and 3/5 IR patients had an Imax of less than 60%; all CR patients had an Imax of greater than 60%. No significant correlation was seen between response to treatment and disease severity on admission. When in vitro T lymphocyte steroid sensitivity was remeasured three months later, there was no difference between the groups.CONCLUSIONSResults suggest that T lymphocyte steroid resistance is an important factor in determining response to steroid treatment in patients with severe UC and may be more predictive of outcome than disease severity.

scholarly journals Use of an anti-pan T-lymphocyte ricin a chain immunotoxin in steroid- resistant acute graft-versus-host disease

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1426-1432 ◽  
Author(s):  
VS Byers ◽  
PJ Henslee ◽  
NA Kernan ◽  
BR Blazar ◽  
R Gingrich ◽  
...  
Keyword(s):  
T Lymphocyte ◽  
Graft Versus Host Disease ◽  
Immunosuppressive Agents ◽  
Allogeneic Bone ◽  
Ricin A Chain ◽  
Steroid Resistant ◽  
Host Disease ◽  
Graft Versus Host ◽  
A Chain ◽  
Ricin A

Abstract Acute steroid-resistant graft-versus-host disease (AGVHD) after allogeneic bone marrow transplantation is frequently fatal. A new treatment for this T-lymphocyte-mediated condition uses an immunotoxin, H65-RTA, comprised of a monoclonal antibody that recognizes the CD5 lymphocyte differentiation antigen coupled to ricin A chain, a cytotoxic enzyme that inhibits protein synthesis. The safety and efficacy of this lymphocyte-targeted immunotoxin was evaluated in patients with severe AGVHD in a phase I-II dose escalation study with group expansion at the two middle doses. Thirty-four patients received up to 14 daily intravenous infusions of the immunotoxin. The principal side effects were constitutional symptoms such as fatigue and myalgias, and hypoalbuminemia with weight gain was seen at all doses. Thirty-two patients were evaluated for improvement or resolution of disease. Durable complete or partial responses were not dose-related and were seen in 16 patients. Skin GVHD had the highest incidence of response (73%), although improvement or resolution in gastrointestinal tract (45%) and liver (28%) GVHD was also noted. Survival in responding patients was significantly prolonged at all times as compared with those with no response (P = .03). Treatment was associated with a rapid decrease in peripheral blood T lymphocytes, which persisted for greater than 1 month after therapy. Anti-immunotoxin antibodies were seen in 6 of the 23 patients tested; these were of low titer and did not block immunotoxin binding to T cells. Results of this study indicate that anti-T-lymphocyte immunotoxins may form a new class of immunosuppressive agents useful in T-lymphocyte-mediated diseases.

scholarly journals A ricin A chain-containing immunotoxin that kills human T lymphocytes in vitro

Blood ◽  
1985 ◽  
Vol 66 (4) ◽  
pp. 908-912 ◽  
Author(s):  
PJ Martin ◽  
JA Hansen ◽  
ES Vitetta
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Protein Synthesis ◽  
T Lymphocytes ◽  
Mononuclear Cells ◽  
Ricin A Chain ◽  
Human T Lymphocytes ◽  
Blood Mononuclear Cells ◽  
A Chain ◽  
Ricin A

Abstract An immunotoxin specific for human T lymphocytes was prepared by coupling an IgG2a anti-CD3 murine monoclonal antibody (64.1) to purified ricin A chain (64.1-A). Treatment of blood mononuclear cells with this immunotoxin at a concentration of 1.7 X 10(-9) mol/L for two hours at 37 degrees C in the presence of 20 mmol/L NH4Cl decreased phytohemagglutinin-stimulated protein synthesis by 95%. In addition, a sensitive culture assay showed that fewer than 0.03% T cells remained after treatment of human bone marrow mononuclear cells with 64.1-A at a concentration of 1.7 X 10(-9) mol/L. The inhibition of protein synthesis could be prevented by preincubating cells with unconjugated 64.1 antibody but not by preincubating cells with a control IgG2a antibody that binds to a different T cell antigen (CD5). At concentrations up to 1 X 10(-8) mol/L, 64.1-A had little effect on blood mononuclear cells from baboons or human myeloid precursors (CFU- GM), which do not express the CD3 antigen recognized by 64.1. Taken together, these results indicate that the toxicity of 64.1-A was specific and that 64.1-A may be a useful reagent for depleting T cells from donor marrow as a means of preventing acute graft-v-host disease after allogeneic bone marrow transplantation.

Immunotoxins up to the present day

1989 ◽  
Vol 9 (2) ◽  
pp. 139-156 ◽  
Author(s):  
Francis A. Drobniewski
Keyword(s):  
Clinical Studies ◽  
Polyclonal Antibodies ◽  
Cell Binding ◽  
Ricin A Chain ◽  
Future Role ◽  
A Chain ◽  
Ricin A

Immunotoxins consist of monoclonal or polyclonal antibodies conjugated to bacterial or plant toxins. The toxins used are typically of the A-B type in which a toxic A chain is coupled to a B chain responsible for cell binding and facilitation of A chain entry into the cytosol. Two broad strategies have been followed: coupling intact toxins, or A chains alone, to antibodies. This review examines current progress in in vitro and in vivo research, including recent clinical studies, concentrating principally on ricin or ricin A chain conjugates. The future role of conjugates using membrane-acting toxins, immunolysins, is also discussed.

scholarly journals Cytotoxicity of a cell-reactive immunotoxin containing ricin A chain is potentiated by an anti-immunotoxin containing ricin B chain.

1984 ◽  
Vol 160 (1) ◽  
pp. 341-346 ◽  
Author(s):  
E S Vitetta ◽  
R J Fulton ◽  
J W Uhr
Keyword(s):  
Cell Surface ◽  
Cell Line ◽  
Ricin A Chain ◽  
Daudi Cell ◽  
A Cell ◽  
A Chain ◽  
Ricin A

In vitro killing of the human Daudi cell line by either univalent [F(ab')] or divalent (IgG) forms of rabbit anti-human Ig (RAHIg) coupled to ricin A chain can be specifically potentiated by a "piggyback" treatment with ricin B chain coupled to goat anti-rabbit Ig (GARIg). When cells are treated with univalent immunotoxin (IT) [F(ab') RAHIg-A] and then cultured, IT can be detected on the cell surface for at least 5 h, since GARIg-B can still enhance killing at this time. These results provide a strategy for in vivo use of A chain- and B chain-containing IT.

Immunotoxin with mistletoe lectin I A-chain and ricin A-chain directed against CD5 antigen of human T-lymphocytes; Comparison of efficiency and specificity

1991 ◽  
Vol 13 (7) ◽  
pp. 1037-1041 ◽  
Author(s):  
A.G. Tonevitsky ◽  
A.Yu. Toptygin ◽  
U. Pfuller ◽  
T.L. Bushueva ◽  
G.V. Ershova ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Mistletoe Lectin ◽  
Ricin A Chain ◽  
Human T Lymphocytes ◽  
A Chain ◽  
Ricin A

scholarly journals Use of an anti-pan T-lymphocyte ricin a chain immunotoxin in steroid- resistant acute graft-versus-host disease

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1426-1432 ◽  
Author(s):  
VS Byers ◽  
PJ Henslee ◽  
NA Kernan ◽  
BR Blazar ◽  
R Gingrich ◽  
...  
Keyword(s):  
T Lymphocyte ◽  
Graft Versus Host Disease ◽  
Immunosuppressive Agents ◽  
Allogeneic Bone ◽  
Ricin A Chain ◽  
Steroid Resistant ◽  
Host Disease ◽  
Graft Versus Host ◽  
A Chain ◽  
Ricin A

Acute steroid-resistant graft-versus-host disease (AGVHD) after allogeneic bone marrow transplantation is frequently fatal. A new treatment for this T-lymphocyte-mediated condition uses an immunotoxin, H65-RTA, comprised of a monoclonal antibody that recognizes the CD5 lymphocyte differentiation antigen coupled to ricin A chain, a cytotoxic enzyme that inhibits protein synthesis. The safety and efficacy of this lymphocyte-targeted immunotoxin was evaluated in patients with severe AGVHD in a phase I-II dose escalation study with group expansion at the two middle doses. Thirty-four patients received up to 14 daily intravenous infusions of the immunotoxin. The principal side effects were constitutional symptoms such as fatigue and myalgias, and hypoalbuminemia with weight gain was seen at all doses. Thirty-two patients were evaluated for improvement or resolution of disease. Durable complete or partial responses were not dose-related and were seen in 16 patients. Skin GVHD had the highest incidence of response (73%), although improvement or resolution in gastrointestinal tract (45%) and liver (28%) GVHD was also noted. Survival in responding patients was significantly prolonged at all times as compared with those with no response (P = .03). Treatment was associated with a rapid decrease in peripheral blood T lymphocytes, which persisted for greater than 1 month after therapy. Anti-immunotoxin antibodies were seen in 6 of the 23 patients tested; these were of low titer and did not block immunotoxin binding to T cells. Results of this study indicate that anti-T-lymphocyte immunotoxins may form a new class of immunosuppressive agents useful in T-lymphocyte-mediated diseases.

scholarly journals Kv1.3 Channel Up-Regulation in Peripheral Blood T Lymphocytes of Patients With Multiple Sclerosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Ioannis Markakis ◽  
Ioannis Charitakis ◽  
Christine Beeton ◽  
Melpomeni Galani ◽  
Elpida Repousi ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Calcium Influx ◽  
Lymphocyte Function ◽  
Kv1.3 Channel ◽  
Kv1.3 Channels

Voltage-gated Kv1.3 potassium channels are key regulators of T lymphocyte activation, proliferation and cytokine production, by providing the necessary membrane hyper-polarization for calcium influx following immune stimulation. It is noteworthy that an accumulating body of in vivo and in vitro evidence links these channels to multiple sclerosis pathophysiology. Here we studied the electrophysiological properties and the transcriptional and translational expression of T lymphocyte Kv1.3 channels in multiple sclerosis, by combining patch clamp recordings, reverse transcription polymerase chain reaction and flow cytometry on freshly isolated peripheral blood T lymphocytes from two patient cohorts with multiple sclerosis, as well as from healthy and disease controls. Our data demonstrate that T lymphocytes in MS, manifest a significant up-regulation of Kv1.3 mRNA, Kv1.3 membrane protein and Kv1.3 current density and therefore of functional membrane channel protein, compared to control groups (p < 0.001). Interestingly, patient sub-grouping shows that Kv1.3 channel density is significantly higher in secondary progressive, compared to relapsing-remitting multiple sclerosis (p < 0.001). Taking into account the tight connection between Kv1.3 channel activity and calcium-dependent processes, our data predict and could partly explain the reported alterations of T lymphocyte function in multiple sclerosis, while they highlight Kv1.3 channels as potential therapeutic targets and peripheral biomarkers for the disease.

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