SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to dec... more SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to decrease mortality, there remains a need for curative therapies for active infections. Uncertainties regarding the duration of post-vaccination immunity and the rapidity of mutational evolution by this virus suggest that it is unwise to rely on preventative measures alone. Dysregulation of endogenous cellular immunity has been implicated in the failure to control COVID-19 infections suggesting that allogeneic T cell therapy using nature’s curative approach to viral infections could successfully be applied to vulnerable patients. Allogeneic virus-specific cytotoxic T lymphocytes (CTLs) have a long track record of safety and efficacy in treating viral infections occurring after allogeneic stem cell transplantation. We hypothesize that this approach can be applied to the treatment of Covid-19. Covid-19 specific CTLs were produced by priming and enriching T cells from convalescent patients using COVID-19 peptides predicted or demonstrated to bind to specific HLA alleles. Utilizing the globally common HLA-A*02:01 allele as the restriction element, 7 peptides from 4 COVID-19 gene/ORF products were identified and used as a pool for serial restimulation and enrichment on a peptide pulsed, HLA-A*02:01 antigen presenting cell monolayer. This preclinical effort produced CTLs of high purity (>95% CD3+/CD8+, >60% positive by tetramer staining) and potency (60% lysis of peptide pulsed targets at an effector to target ratio of 3:1) in sufficient quantities for clinical application. Trials using these TVGN-489 CTLs and those produced with other SARS-COV-2 peptides and HLA restriction elements will hopefully be launched shortly.
... Antigen-Specific T-Cell Receptors and their Reactions with Complexes Formed by Peptides with ... more ... Antigen-Specific T-Cell Receptors and their Reactions with Complexes Formed by Peptides with Major Histocompatibility Complex Proteins. Herman N. Eisen, Yuri Sykulev, Theodore J. Tsomides. ... support, and the reaction evaluated by surface plasmon resonance (SPR, below). ...
Adhesion molecules are known to mediate cell-cell interactions, particularly those between T cell... more Adhesion molecules are known to mediate cell-cell interactions, particularly those between T cells and antigen-presenting or target cells. Recent studies identified ICAM-1 as a co-stimulatory ligand that binds to lymphocyte function associated antigen-1 (LFA-1), thereby promoting the activation of T cells. As ICAM-1 is expressed on virtually any cell, it becomes a crucial molecule for the activation of CD8(+) T cells in the absence of co-stimulation provided by CD80 and CD86 molecules. In addition, ICAM-1 might function as cell-surface receptor, capable of initiating intracellular signaling. ICAM-1 is associated with other cell molecules, including MHC-I proteins, and our recent data show that productive engagement of ICAM-1 on target cells leads to recruitment of the MHC-I proteins to the contact area and enhances presentation of cognate peptide MHC-I complexes to cytotoxic T cells.
Successful elimination of virus infected and cancer cells requires CTL to exercise highly sensiti... more Successful elimination of virus infected and cancer cells requires CTL to exercise highly sensitive and efficient cytolytic activity. There are two principal mechanisms responsible for the sensitivity and the efficiency of cytolysis. The sensitivity is determined by focused delivery of cytolytic granules to the secretory domain located within the cSMAC of IS. The MTOC polarization to the synaptic interface is a critical event of the granule delivery and is mediated by the ADAP-associated dynein motors attached to the pSMAC. A stable pSMAC also responsible for the confinement of released granules at the CTL/target cell interface that enables killing with a minimal amount of released granules. Thus, segregation on adhesion molecules and the pSMAC formation play an important role in the mechanism controlling the sensitivity of cytolysis. Another essential quality of the CTL-mediated cytolysis is the kinetics of target cell destruction that reflects efficiency of the cytolytic activity. The efficiency is regulated by the kinetics of the granule delivery to the secretory domain that occurs via “short” or “long” paths. The choice of the path is determined by the kinetics of the TCR early signaling, but not by the magnitude of the signaling. Thus, variations in the TCR signaling kinetics constitute the mechanism controlling the efficiency of the cytolytic activity. Whether similar mechanisms are utilized by other cytolytic effectors such as NK cells remains will be discussed.
SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to dec... more SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to decrease mortality, there remains a need for curative therapies for active infections. Uncertainties regarding the duration of post-vaccination immunity and the rapidity of mutational evolution by this virus suggest that it is unwise to rely on preventative measures alone. Dysregulation of endogenous cellular immunity has been implicated in the failure to control COVID-19 infections suggesting that allogeneic T cell therapy using nature’s curative approach to viral infections could successfully be applied to vulnerable patients. Allogeneic virus-specific cytotoxic T lymphocytes (CTLs) have a long track record of safety and efficacy in treating viral infections occurring after allogeneic stem cell transplantation. We hypothesize that this approach can be applied to the treatment of Covid-19. Covid-19 specific CTLs were produced by priming and enriching T cells from convalescent patients using COVID-19 peptides predicted or demonstrated to bind to specific HLA alleles. Utilizing the globally common HLA-A*02:01 allele as the restriction element, 7 peptides from 4 COVID-19 gene/ORF products were identified and used as a pool for serial restimulation and enrichment on a peptide pulsed, HLA-A*02:01 antigen presenting cell monolayer. This preclinical effort produced CTLs of high purity (>95% CD3+/CD8+, >60% positive by tetramer staining) and potency (60% lysis of peptide pulsed targets at an effector to target ratio of 3:1) in sufficient quantities for clinical application. Trials using these TVGN-489 CTLs and those produced with other SARS-COV-2 peptides and HLA restriction elements will hopefully be launched shortly.
... Antigen-Specific T-Cell Receptors and their Reactions with Complexes Formed by Peptides with ... more ... Antigen-Specific T-Cell Receptors and their Reactions with Complexes Formed by Peptides with Major Histocompatibility Complex Proteins. Herman N. Eisen, Yuri Sykulev, Theodore J. Tsomides. ... support, and the reaction evaluated by surface plasmon resonance (SPR, below). ...
Adhesion molecules are known to mediate cell-cell interactions, particularly those between T cell... more Adhesion molecules are known to mediate cell-cell interactions, particularly those between T cells and antigen-presenting or target cells. Recent studies identified ICAM-1 as a co-stimulatory ligand that binds to lymphocyte function associated antigen-1 (LFA-1), thereby promoting the activation of T cells. As ICAM-1 is expressed on virtually any cell, it becomes a crucial molecule for the activation of CD8(+) T cells in the absence of co-stimulation provided by CD80 and CD86 molecules. In addition, ICAM-1 might function as cell-surface receptor, capable of initiating intracellular signaling. ICAM-1 is associated with other cell molecules, including MHC-I proteins, and our recent data show that productive engagement of ICAM-1 on target cells leads to recruitment of the MHC-I proteins to the contact area and enhances presentation of cognate peptide MHC-I complexes to cytotoxic T cells.
Successful elimination of virus infected and cancer cells requires CTL to exercise highly sensiti... more Successful elimination of virus infected and cancer cells requires CTL to exercise highly sensitive and efficient cytolytic activity. There are two principal mechanisms responsible for the sensitivity and the efficiency of cytolysis. The sensitivity is determined by focused delivery of cytolytic granules to the secretory domain located within the cSMAC of IS. The MTOC polarization to the synaptic interface is a critical event of the granule delivery and is mediated by the ADAP-associated dynein motors attached to the pSMAC. A stable pSMAC also responsible for the confinement of released granules at the CTL/target cell interface that enables killing with a minimal amount of released granules. Thus, segregation on adhesion molecules and the pSMAC formation play an important role in the mechanism controlling the sensitivity of cytolysis. Another essential quality of the CTL-mediated cytolysis is the kinetics of target cell destruction that reflects efficiency of the cytolytic activity. The efficiency is regulated by the kinetics of the granule delivery to the secretory domain that occurs via “short” or “long” paths. The choice of the path is determined by the kinetics of the TCR early signaling, but not by the magnitude of the signaling. Thus, variations in the TCR signaling kinetics constitute the mechanism controlling the efficiency of the cytolytic activity. Whether similar mechanisms are utilized by other cytolytic effectors such as NK cells remains will be discussed.
Uploads
Papers by Yuri Sykulev