Development of a CD8 co-receptor independent T-cell receptor specific for tumor-associated antigen MAGE-A4 for next generation T-cell-based immunotherapy.

The cancer-testis antigen MAGE-A4 is an attractive target for T-cell-based immunotherapy, especially for indications with unmet clinical need like non-small cell lung or triple-negative breast cancer. An unbiased CD137-based sorting approach was first used to identify an immunogenic MAGE-A4-derived epitope (GVYDGREHTV) that was properly processed and presented on human leukocyte antigen (HLA)-A2 molecules encoded by the HLA-A*02:01 allele. To isolate high-avidity T cells via subsequent multimer sorting, an in vitro priming approach using HLA-A2-negative donors was conducted to bypass central tolerance to this self-antigen. Pre-clinical parameters of safety and activity were assessed in a comprehensive set of in vitro and in vivo studies. A MAGE-A4-reactive, HLA-A2-restricted T-cell receptor (TCR) was isolated from primed T cells of an HLA-A2-negative donor. The respective TCR-T-cell (TCR-T) product bbT485 was demonstrated pre-clinically to have a favorable safety profile and superior in vivo potency compared with TCR-Ts expressing a TCR derived from a tolerized T-cell repertoire to self-antigens. This natural high-avidity TCR was found to be CD8 co-receptor independent, allowing effector functions to be elicited in transgenic CD4+ T helper cells. These CD4+ TCR-Ts supported an anti-tumor response by direct killing of MAGE-A4-positive tumor cells and upregulated hallmarks associated with helper function, such as CD154 expression and release of key cytokines on tumor-specific stimulation. The extensive pre-clinical assessment of safety and in vivo potency of bbT485 provide the basis for its use in TCR-T immunotherapy studies. The ability of this non-mutated high-avidity, co-receptor-independent TCR to activate CD8+ and CD4+ T cells could potentially provide enhanced cellular responses in the clinical setting through the induction of functionally diverse T-cell subsets that goes beyond what is currently tested in the clinic.

Davari K ，Holland T ，Prassmayer L ，Longinotti G ，Ganley KP ，Pechilis LJ ，Diaconu I ，Nambiar PR ，Magee MS ，Schendel DJ ，Sommermeyer D ，Ellinger C ... -  《Journal for ImmunoTherapy of Cancer》

Chronic TCR-MHC (self)-interactions limit the functional potential of TCR affinity-increased CD8 T lymphocytes.

Duong MN ，Erdes E ，Hebeisen M ，Rufer N ... -  《Journal for ImmunoTherapy of Cancer》

T-cell receptor gene therapy targeting melanoma-associated antigen-A4 inhibits human tumor growth in non-obese diabetic/SCID/γcnull mice.

Adoptive cell therapy with lymphocytes that have been genetically engineered to express tumor-reactive T-cell receptors (TCR) is a promising approach for cancer immunotherapy. We have been exploring the development of TCR gene therapy targeting cancer/testis antigens, including melanoma-associated antigen (MAGE) family antigens, that are ideal targets for adoptive T-cell therapy. The efficacy of TCR gene therapy targeting MAGE family antigens, however, has not yet been evaluated in vivo. Here, we demonstrate the in vivo antitumor activity in immunodeficient non-obese diabetic/SCID/γc(null) (NOG) mice of human lymphocytes genetically engineered to express TCR specific for the MAGE-A4 antigen. Polyclonal T cells derived from human peripheral blood mononuclear cells were transduced with the αβ TCR genes specific for MAGE-A4, then adoptively transferred into NOG mice inoculated with MAGE-A4 expressing human tumor cell lines. The transferred T cells maintained their effector function in vivo, infiltrated into tumors, and inhibited tumor growth in an antigen-specific manner. The combination of adoptive cell therapy with antigen peptide vaccination enhanced antitumor activity, with improved multifunctionality of the transferred cells. These data suggest that TCR gene therapy with MAGE-A4-specific TCR is a promising strategy to treat patients with MAGE-A4-expressing tumors; in addition, the acquisition of multifunctionality in vivo is an important factor to predict the quality of the T-cell response during adoptive therapy with human lymphocytes.

Shirakura Y ，Mizuno Y ，Wang L ，Imai N ，Amaike C ，Sato E ，Ito M ，Nukaya I ，Mineno J ，Takesako K ，Ikeda H ，Shiku H ... -  《-》

Generation and characterization of HLA-A2 transgenic mice expressing the human TCR 1G4 specific for the HLA-A2 restricted NY-ESO-1(157-165) tumor-specific peptide.

NY-ESO-1 is a tumor-specific, highly immunogenic, human germ cell antigen of the MAGE-1 family that is a promising vaccine and cell therapy candidate in clinical trial development. The mouse genome does not encode an NY-ESO-1 homolog thereby not subjecting transgenic T-cells to thymic tolerance mechanisms that might impair in-vivo studies. We hypothesized that an NY-ESO-1 T cell receptor (TCR) transgenic mouse would provide the unique opportunity to study avidity of TCR response against NY-ESO-1 for tumor vaccine and cellular therapy development against this clinically relevant and physiological human antigen. To study in vitro and in vivo the requirements for shaping an effective T cell response against the clinically relevant NY-ESO-1, we generated a C57BL/6 HLA-A*0201 background TCR transgenic mouse encoding the 1G4 TCR specific for the human HLA-A2 restricted, NY-ESO-1157-165 SLLMWITQC (9C), initially identified in an NY-ESO-1 positive melanoma patient. The HLA-A*0201 restricted TCR was positively selected on both CD4+ and CD8+ cells. Mouse 1G4 T cells were not activated by endogenous autoimmune targets or a large library of non-cognate viral antigens. In contrast, their activation by HLA-A2 NY-ESO-1157-165 complexes was evident by proliferation, CD69 upregulation, interferon-γ production, and interleukin-2 production, and could be tuned using a twofold higher affinity altered peptide ligand, NY-ESO-1157-165V. NY-ESO-1157-165V recombinant vaccination of syngeneic mice adoptively transferred with m1G4 CD8+ T cells controlled tumor growth in vivo. 1G4 transgenic mice suppressed growth of syngeneic methylcholanthrene (MCA) induced HHD tumor cells expressing the full-length human NY-ESO-1 protein but not MCA HHD tumor cells lacking NY-ESO-1. The 1G4 TCR mouse model for the physiological human TCR against the clinically relevant antigen, NY-ESO-1, is a valuable tool with the potential to accelerate clinical development of NY-ESO-1-targeted T-cell and vaccine therapies.

Shenderov E ，Kandasamy M ，Gileadi U ，Chen J ，Shepherd D ，Gibbs J ，Prota G ，Silk JD ，Yewdell JW ，Cerundolo V ... -  《Journal for ImmunoTherapy of Cancer》

A TCR targeting the HLA-A*0201-restricted epitope of MAGE-A3 recognizes multiple epitopes of the MAGE-A antigen superfamily in several types of cancer.

Chinnasamy N ，Wargo JA ，Yu Z ，Rao M ，Frankel TL ，Riley JP ，Hong JJ ，Parkhurst MR ，Feldman SA ，Schrump DS ，Restifo NP ，Robbins PF ，Rosenberg SA ，Morgan RA ... -  《-》