T Cell Activation by Antibody-Like Immunoreceptors: Increase in Affinity of the Single-Chain Fragment Domain above Threshold Does Not Increase T Cell Activation against Antigen-Positive Target Cells but Decreases Selectivity

AbstractHER3 is a member of the EGF receptor family and elevated expression is associated with cancer progression and therapy resistance. HER3-specific T-cell engagers might be a suitable treatment option to circumvent the limited efficacy observed for HER3-blocking antibodies in clinical trials. In this study, we developed bispecific antibodies for T-cell retargeting to HER3-expressing tumor cells, utilizing either a single-chain diabody format (scDb) with one binding site for HER3 and one for CD3 on T-cells or a trivalent bispecific scDb-scFv fusion protein exhibiting an additional binding site for HER3. The scDb-scFv showed increased binding to HER3-expressing cancer cell lines compared to the scDb and consequently more effective T-cell activation and T-cell proliferation. Furthermore, the bivalent binding mode of the scDb-scFv for HER3 translated into more potent T-cell mediated cancer cell killing, and allowed to discriminate between moderate and low HER3-expressing target cells. Thus, our study demonstrated the applicability of HER3 for T-cell retargeting with bispecific antibodies, even at moderate expression levels, and the increased potency of an avidity-mediated specificity gain, potentially resulting in a wider safety window of bispecific T-cell engaging antibodies targeting HER3.

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

Blood ◽

10.1182/blood.v108.11.3889.3889 ◽

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.

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P07.01 A modular and controllable T cell therapy platform for AML

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-itoc8.42 ◽

2021 ◽

Vol 9 (Suppl 1) ◽

pp. A22.2-A23

Author(s):

M Benmebarek ◽

B Loureiro Cadilha ◽

M Herrmann ◽

S Schmitt ◽

S Lesch ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Therapy ◽

T Cell Activation ◽

Tumour Cell ◽

Cell Activation ◽

Cell Lysis ◽

Target Cells ◽

Single Chain

BackgroundTargeted immunotherapies have shown limited success in the context of acute myeloid leukemia (AML). The mutational landscape, heterogeneity attributed to this malignancy and toxicities associated with the targeting of myeloid lineage antigens, it has become apparent that a modular and controllable cell therapy approach with the potential to target multiple antigens is required. We propose a controlled ACT approach, where T cells are equipped with synthetic agonistic receptors (SARs) that are selectively activated only in the presence of a target AML-associated antigen, and a cross-linking tandem single chain variable fragment (taFv) specific for both (SAR) T cell and tumour cell.Materials and MethodsA SAR composed of an extracellular EGFRvIII, trans- membrane CD28, and intracellular CD28 and CD3z domains was fused via overlap- extension PCR cloning. T cells were retrovirally transduced to stably express our SAR construct. SAR-specific taFvs that target AML-associated antigens were designed and expressed in Expi293FTM cells and purified by nickel affinity and size exclusion chromatography (SEC). We validated our approach in three human cancer models and patient-derived AML blasts expressing our AML-associated target antigens CD33 and CD123.ResultsAnti-CD33-EGFRvIII and anti-CD123 EGFRvIII taFv, monovalently selective for our SAR, induced conditional antigen-dependent activation, proliferation and differentiation of SAR-T cells. Further, SAR T cells bridged to their target cells by taFv could form functional immunological synapses, resulting in efficient tumor cell lysis with specificity towards CD33-expressing AML cells. SAR-taFv combination could also mediate specific cytotoxicity against patient-derived AML blasts and leukemic stem cells whilst driving SAR T cell activation. In vivo, treatment with SAR-taFv combination could efficiently eradicate leukemia and enhance survival in an AML xenograft models. Furthermore, we could show selective activation of SAR T cells, as well as a controllable reversibility and modularity of said activation upon depletion of the T cell engaging molecule, both in vitro and in vivo.ConclusionsHere we apply the SAR-taFv platform in efforts to deliver specific and conditional activation of SAR-transduced T cells, and targeted tumour cell lysis. The modularity of our platform will allow for a multi-targeting ACT approach with the potential to translate the ACT successes of B cell malignancies to AML. With a lack of truly specific AML antigens, it is invaluable that this approach possesses an intrinsic safety switch via its taFv facet. Moreover, we are able to circumvent pan-T cell activation due to the specific targeting and activation of SAR T cells.Disclosure InformationM. Benmebarek: None. B. Loureiro Cadilha: None. M. Herrmann: None. S. Schmitt: None. S. Lesch: None. S. Stoiber: None. A. Darwich: None. C. Augsberger: None. B. Brauchle: None. M. Schwerdtfeger: None. A. Gottschlich: None. A. Gottschlich Rataj: None. N.C. Fenn: None. C. Klein: None. M. Subklewe: None. S. Endres: None. K. Hopfner: None. S. Kobold: None.

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Costimulation by B7 Modulates Specificity of Cytotoxic T Lymphocytes: A Missing Link That Explains Some Bystander T Cell Activation

Journal of Experimental Medicine ◽

10.1084/jem.186.10.1787 ◽

1997 ◽

Vol 186 (10) ◽

pp. 1787-1791 ◽

Cited By ~ 10

Author(s):

Pan Zheng ◽

Yang Liu

Keyword(s):

Cell Proliferation ◽

T Cells ◽

Influenza Virus ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

T Cell Proliferation ◽

Target Cells ◽

Cell Proliferation And Differentiation ◽

Proliferation And Differentiation

It has been proposed that some bystander T cell activation may in fact be due to T cell antigen receptor (TCR) cross-reactivity that is too low to be detected by the effector cytotoxic T lymphocyte (CTL). However, this hypothesis is not supported by direct evidence since no TCR ligand is known to induce T cell proliferation and differentiation without being recognized by the effector CTL. Here we report that transgenic T cells expressing a T cell receptor to influenza virus A/NT/68 nucleoprotein (NP) 366-374:Db complexes clonally expand and become effector CTLs in response to homologous peptides from either A/PR8/34 (H1N1), A/AA/60 (H2N2), or A/NT/68 (H3N2). However, the effector T cells induced by each of the three peptides kill target cells pulsed with NP peptides from the H3N2 and H2N2 viruses, but not from the H1N1 virus. Thus, NP366–374 from influenza virus H1N1 is the first TCR ligand that can induce T cell proliferation and differentiation without being recognized by CTLs. Since induction of T cell proliferation was mediated by antigen-presenting cells that express costimulatory molecules such as B7, we investigated if cytolysis of H1N1 NP peptide–pulsed targets can be restored by expressing B7-1 on the target cells. Our results revealed that this is the case. These data demonstrated that costimulatory molecule B7 modulates antigen specificity of CTLs, and provides a missing link that explains some of the bystander T cell activation.

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T-cell activation and B-cell depletion in chimpanzees treated with a bispecific anti-CD19/anti-CD3 single-chain antibody construct

Cancer Immunology Immunotherapy ◽

10.1007/s00262-005-0001-1 ◽

2005 ◽

Vol 55 (5) ◽

pp. 503-514 ◽

Cited By ~ 73

Author(s):

Bernd Schlereth ◽

Cornelia Quadt ◽

Torsten Dreier ◽

Peter Kufer ◽

Grit Lorenczewski ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

T Cell Activation ◽

Cell Activation ◽

Cell Depletion ◽

B Cell Depletion ◽

Single Chain ◽

Single Chain Antibody

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CD18 Antibody Application Blocks Unwanted Off-Target T Cell Activation Caused by Bispecific Antibodies

Cancers ◽

10.3390/cancers13184596 ◽

2021 ◽

Vol 13 (18) ◽

pp. 4596

Author(s):

Joseph Kauer ◽

Fabian Vogt ◽

Ilona Hagelstein ◽

Sebastian Hörner ◽

Melanie Märklin ◽

...

Keyword(s):

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Lymphoid Cells ◽

Bispecific Antibodies ◽

Target Cells ◽

Cytokine Release ◽

Life Threatening ◽

Blocking Antibodies

T cell-recruiting bispecific antibodies (bsAbs) are successfully used for the treatment of cancer. However, effective treatment with bsAbs is so far hampered by severe side effects, i.e., potentially life-threatening cytokine release syndrome. Off-target T cell activation due to binding of bispecific CD3 antibodies to T cells in the absence of target cells may contribute to excessive cytokine release. We report here, in an in vitro setting, that off-target T cell activation is induced by bsAbs with high CD3 binding affinity and increased by endothelial- or lymphoid cells that act as stimulating bystander cells. Blocking antibodies directed against the adhesion molecules CD18/CD54 or CD2/CD58 markedly reduced this type of off-target T cell activation. CD18 blockade—in contrast to CD2—did not affect the therapeutic activity of various bsAbs. Since CD18 antibodies have been shown to be safely applicable in patients, blockade of this integrin holds promise as a potential target for the prevention of unwanted off-target T cell activation and allows the application of truly effective bsAb doses.

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Brucella Peptide Cross-Reactive MHC I Presentation Activates SIINFEKL-Specific TCR Expressing T Cells

10.1101/301465 ◽

2018 ◽

Author(s):

Jerome S. Harms ◽

Mike Khan ◽

Cherisse Hall ◽

Gary A. Splitter ◽

E. Jane Homan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Pathogenic Bacteria ◽

Cell Activation ◽

Immune Surveillance ◽

Cross Reactivity ◽

Near Neighbor ◽

Target Cells ◽

Mhc I

ABSTRACTBrucella spp are intracellular pathogenic bacteria remarkable in their ability to escape immune surveillance and therefore inflict a state of chronic disease within the host. To enable further immune response studies, Brucella were engineered to express the well characterized chicken ovalbumin (OVA). Surprisingly, we found that CD8 T cells bearing T cell receptors (TCR) nominally specific for the OVA peptide SIINFEKL (OT-1) reacted to parental Brucella-infected targets as well as OVA-expressing Brucella variants in cytotoxicity assays. Furthermore, splenocytes from Brucella immunized mice produced IFN-γ and exhibited cytotoxicity in response to SIINFEKL-pulsed target cells. To determine if the SIINFEKL-reactive OT-1 TCR could be cross-reacting to Brucella peptides, we searched the Brucella proteome using an algorithm to generate a list of near-neighbor nonamer peptides that would bind to H2Kb. Selecting five Brucella peptide candidates, along with controls, we verified that several of these peptides mimicked SIINFEKL resulting in T cell activation through the “SIINFEKL-specific” TCR. Activation was dependent on peptide concentration as well as sequence. Our results underscore the complexity and ubiquity of cross-reactivity in T cell recognition. This cross-reactivity may enable microbes such as Brucella to escape immune surveillance by presenting peptides similar to the host, and may also lead to the activation of autoreactive T cells.

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Bispecific T-Cell Engagers Targeting Membrane-Bound IgE

Biomedicines ◽

10.3390/biomedicines9111568 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1568

Author(s):

Aleksandra Rodak ◽

Gerhard Stadlmayr ◽

Katharina Stadlbauer ◽

Dominic Lichtscheidl ◽

Madhusudhan Reddy Bobbili ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

T Cell Activation ◽

Cell Activation ◽

Jurkat Cells ◽

Single Chain ◽

Ige Antibodies ◽

Serum Ige ◽

Single Chain Fv ◽

Membrane Bound

The increased incidence of allergies and asthma has sparked interest in IgE, the central player in the allergic response. Interaction with its high-affinity receptor FcεRI leads to sensitization and allergen presentation, extracellular membrane-proximal domain in membrane IgE can act as an antigen receptor on B cells, and the interaction with low-affinity IgE receptor CD23 additionally influences its homeostatic range. Therapeutic anti-IgE antibodies act by the inhibition of IgE functions by interfering with its receptor binding or by the obliteration of IgE-B cells, causing a reduction of serum IgE levels. Fusion proteins of antibody fragments that can act as bispecific T-cell engagers have proven very potent in eliciting cytotoxic T-lymphocyte-mediated killing. We have tested five anti-IgE Fc antibodies, recognizing different epitopes on the membrane-expressed IgE, for the ability to elicit specific T-cell activation when expressed as single-chain Fv fragments fused with anti-CD3ε single-chain antibody. All candidates could specifically stain the cell line, expressing the membrane-bound IgE-Fc and bind to CD3-positive Jurkat cells, and the specific activation of engineered CD3-overexpressing Jurkat cells and non-stimulated CD8-positive cells was demonstrated for 8D6- and ligelizumab-based bispecific antibodies. Thus, such anti-IgE antibodies have the potential to be developed into agents that reduce the serum IgE concentration by lowering the numbers of IgE-secreting cells.

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The Role of Perforin

Croatian Nursing Journal ◽

10.24141/2/5/1/7 ◽

2021 ◽

Vol 5 (1) ◽

pp. 75-82

Author(s):

Davorka Švegar

Keyword(s):

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Theoretical Research ◽

Target Cells ◽

Colon Cancer Cell Lines ◽

Literature Reviews ◽

Ebsco Host ◽

Ht 29

Some literature reviews have been carried out about the role of perforin in medicine. The first step involved a systematic search to identify relevant studies published between 2001 and 2019 in the following electronic databases - EBSCO host, Scopus, Science Direct, Web of Science, and Elsevier. By analyzing the available literature, it can be concluded that perforin plays an important role in cytoxical activity of natural killer cells (NK) and CD8+ T cell. NK and CD8+use the same mechanism for destroying target cells. This article cites the disease hemophagocytic lymphohistiocytosis (HLH) which is characterized by heavy abnormalities in the immune system. The point is that this disease is caused by perforin gene mutation. The key is the application of properly sensitized dendritic cells (DCs) because they are effective in immunotherapy against cancer. It may be effective in γ-irradiated colon cancer cell lines HT-29. Growth hormone inhibiting hormone (GIH) induces maturation and activation of DCs. In that way, GIH-Dcs shows increased cytotoxic activity and higher perforin and granzyme expression. So, this means that theoretical research has shown that efficient activity against cancer is induced when DCs are sensitized with γ-irradiated cancer cells. In that way, through a direct increase of cytotoxicity and indirect T cell activation,there can beanti-tumor activity. It is suggested to continue scientific research about the role of perforin in the future.

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T Cell Activation Machinery: Form and Function in Natural and Engineered Immune Receptors

International Journal of Molecular Sciences ◽

10.3390/ijms21197424 ◽

2020 ◽

Vol 21 (19) ◽

pp. 7424

Author(s):

Nicholas J. Chandler ◽

Melissa J. Call ◽

Matthew E. Call

Keyword(s):

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Immune Cell ◽

Single Chain ◽

Design Work ◽

Cell Therapies ◽

Form And Function ◽

Car T ◽

And Function

The impressive success of chimeric antigen receptor (CAR)-T cell therapies in treating advanced B-cell malignancies has spurred a frenzy of activity aimed at developing CAR-T therapies for other cancers, particularly solid tumors, and optimizing engineered T cells for maximum clinical benefit in many different disease contexts. A rapidly growing body of design work is examining every modular component of traditional single-chain CARs as well as expanding out into many new and innovative engineered immunoreceptor designs that depart from this template. New approaches to immune cell and receptor engineering are being reported with rapidly increasing frequency, and many recent high-quality reviews (including one in this special issue) provide comprehensive coverage of the history and current state of the art in CAR-T and related cellular immunotherapies. In this review, we step back to examine our current understanding of the structure-function relationships in natural and engineered lymphocyte-activating receptors, with an eye towards evaluating how well the current-generation CAR designs recapitulate the most desirable features of their natural counterparts. We identify key areas that we believe are under-studied and therefore represent opportunities to further improve our grasp of form and function in natural and engineered receptors and to rationally design better therapeutics.

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