Honors & Awards


  • Postdoctoral Fellowship, Dr. Mildred-Scheel-Foundation, German Cancer Aid (01/2019-)

Professional Education


  • Residency, Goethe-University-Hospital Frankfurt, Internal Medicine and Hematology and Oncology
  • Doctor of Medicine, Albert Ludwigs Universitat Freiburg (2016)
  • Staatsexamen, Albert Ludwigs Universitat Freiburg (2014)

Stanford Advisors


All Publications


  • Invariant Natural Killer T Cell Subsets Have Diverse Graft-Versus-Host-Disease-Preventing and Anti-Tumor Effects. Blood Maas-Bauer, K., Lohmeyer, J. K., Hirai, T., Lopes Ramos, T., Fazal, F. M., Litzenburger, U. M., Yost, K. E., Ribado, J. V., Kambham, N., Wenokur, A., Lin, P., Alvarez, M., Mavers, M., Baker, J., Bhatt, A. S., Chang, H., Simonetta, F., Negrin, R. S. 2021

    Abstract

    Invariant Natural Killer T (iNKT) cells are a T cell subset with potent immunomodulatory properties. Experimental evidence in mice and observational studies in humans indicate that iNKT cells have antitumor potential as well as the ability to suppress acute and chronic Graft-versus-Host-Disease (GvHD). Murine iNKT cells differentiate during thymic development into iNKT1, iNKT2 and iNKT17 sublineages, which differ transcriptomically and epigenomically, and have subset-specific developmental requirements. Whether distinct iNKT sublineages also differ in their antitumor effect and their ability to suppress GvHD is currently unknown. In this work, we generated highly purified murine iNKT-sublineages, characterized their transcriptomic and epigenomic landscape, and assessed specific functions. We demonstrate that iNKT2 and iNKT17, but not iNKT1 cells, efficiently suppress T cell activation in vitro and mitigate murine acute GvHD in vivo. Conversely, we show that iNKT1 cells display the highest antitumor activity against murine B-cell lymphoma cells both in vitro and in vivo. Thus, we demonstrate for the first time that iNKT sublineages have distinct and different functions, with iNKT1 cells having the highest antitumor activity and iNKT2 and iNKT17 cells having immune-regulatory properties. These results have important implications for the translation of iNKT cell therapies to the clinic for cancer immunotherapy as well as for GvHD prevention and treatment.

    View details for DOI 10.1182/blood.2021010887

    View details for PubMedID 34036317

  • Selective expansion of regulatory T cells using an orthogonal IL-2/IL-2 receptor system facilitates transplantation tolerance. The Journal of clinical investigation Hirai, T., Ramos, T. L., Lin, P., Simonetta, F., Su, L. L., Picton, L. K., Baker, J., Lin, J., Li, P., Seo, K., Lohmeyer, J. K., Wagers, S. B., Mavers, M., Leonard, W. J., Blazar, B. R., Garcia, K. C., Negrin, R. S. 2021; 131 (8)

    Abstract

    Adoptive transfer of Tregs has been shown to improve alloengraftment in animal models. However, it is technically challenging to expand Tregs ex vivo for the purpose of infusing large numbers of cells in the clinic. We demonstrate an innovative approach to engineering an orthogonal IL-2/IL-2 receptor (IL-2R) pair, the parts of which selectively interact with each other, transmitting native IL-2 signals, but do not interact with the natural IL-2 or IL-2R counterparts, thereby enabling selective stimulation of target cells in vivo. Here, we introduced this orthogonal IL-2R into Tregs. Upon adoptive transfer in a murine mixed hematopoietic chimerism model, orthogonal IL-2 injection significantly promoted orthogonal IL-2R+Foxp3GFP+CD4+ cell proliferation without increasing other T cell subsets and facilitated donor hematopoietic cell engraftment followed by acceptance of heart allografts. Our data indicate that selective target cell stimulation enabled by the engineered orthogonal cytokine receptor improves Treg potential for the induction of organ transplantation tolerance.

    View details for DOI 10.1172/JCI139991

    View details for PubMedID 33855972

  • Allogeneic Chimeric Antigen receptor-invariant Natural Killer T Cells Exert Both Direct and Indirect Antitumor Effects through Host Cd8 T Cell cross-priming Simonetta, F., Hirai, T., Lohmeyer, J. K., Maas-Bauer, K., Alvarez, M., Wenokur, A. S., Baker, J., Aalipour, A., Haile, S., Mackall, C. L., Negrin, R. S. SPRINGERNATURE. 2020: 259–60
  • Molecular Imaging of Chimeric Antigen Receptor T Cells by ICOS-ImmunoPET. Clinical cancer research : an official journal of the American Association for Cancer Research Simonetta, F., Alam, I. S., Lohmeyer, J. K., Sahaf, B., Good, Z., Chen, W., Xiao, Z., Hirai, T., Scheller, L., Engels, P., Vermesh, O., Robinson, E., Haywood, T., Sathirachinda, A., Baker, J., Malipatlolla, M. B., Schultz, L. M., Spiegel, J. Y., Lee, J. T., Miklos, D. B., Mackall, C. L., Gambhir, S. S., Negrin, R. 2020

    Abstract

    PURPOSE: Immunomonitoring of chimeric antigen receptor (CAR) T cells relies primarily on their quantification in the peripheral blood, which inadequately quantifies their biodistribution and activation status in the tissues. Non-invasive molecular imaging of CAR T cells by positron emission tomography (PET) is a promising approach with the ability to provide spatial, temporal and functional information. Reported strategies rely on the incorporation of reporter transgenes or ex vivo biolabeling, significantly limiting the application of CAR T cell molecular imaging. In the present study, we assessed the ability of antibody-based PET (immunoPET) to non-invasively visualize CAR T cells.EXPERIMENTAL DESIGN: After analyzing human CAR T cells in vitro and ex vivo from patient samples to identify candidate targets for immunoPET, we employed a syngeneic, orthotopic murine tumor model of lymphoma to assess the feasibility of in vivo tracking of CAR T cells by immunoPET using the 89Zr-DFO-anti-ICOS tracer we previously reported.RESULTS: Analysis of human CD19-CAR T cells during activation identified the Inducible T-cell COStimulator (ICOS) as a potential target for immunoPET. In a preclinical tumor model, 89Zr-DFO-ICOS mAb PET-CT imaging detected significantly higher signal in specific bone marrow-containing skeletal sites of CAR T cell treated mice compared with controls. Importantly, administration of ICOS-targeting antibodies at tracer doses did not interfere with CAR T cell persistence and function.CONCLUSIONS: This study highlights the potential of ICOS-immunoPET imaging for monitoring of CAR T cell therapy, a strategy readily applicable to both commercially available and investigational CAR T cells.

    View details for DOI 10.1158/1078-0432.CCR-20-2770

    View details for PubMedID 33087332

  • Visualization of activated T cells by OX40-immunoPET as a strategy for diagnosis of acute Graft-versus-Host-Disease. Cancer research Alam, I. S., Simonetta, F., Scheller, L., Mayer, A. T., Murty, S., Vermesh, O., Nobashi, T. W., Lohmeyer, J. K., Hirai, T., Baker, J., Lau, K. H., Negrin, R., Gambhir, S. S. 2020

    Abstract

    Graft versus host disease (GvHD) is a major complication of allogeneic hematopoietic cell transplantation (HCT), mediated primarily by donor T cells that become activated and attack host tissues. Non-invasive strategies detecting T cell activation would allow for early diagnosis and possibly more effective management of HCT recipients. Positron emission tomography (PET) imaging is a sensitive and clinically relevant modality ideal for GvHD diagnosis and there is a strong rationale for the use of PET tracers that can monitor T cell activation and expansion with high specificity. The tumor necrosis factor (TNF) receptor superfamily member OX40 (CD134) is a cell surface marker that is highly specific for activated T cells, is upregulated during GvHD, and mediates disease pathogenesis. We recently reported the development of an antibody-based activated T cell imaging agent targeting OX40. In the present study, we visualize the dynamics of OX40 expression in a major histocompatibility complex (MHC)-mismatch mouse model of acute GvHD using OX40-immunoPET. This approach enabled visualization of T cell activation at early stages of disease, prior to overt clinical symptoms with high sensitivity and specificity. This study highlights the potential utility of the OX40 PET imaging as a new strategy for GvHD diagnosis and therapy monitoring.

    View details for DOI 10.1158/0008-5472.CAN-20-1149

    View details for PubMedID 32900772

  • Engineered IL-2 Cytokine-Cytokine Receptor Complex Enables Selective Expansion of Regulatory T Cells and Facilitates Establishment of Organ Transplantation Tolerance Hirai, T., Simonetta, F., Su, L. L., Picton, L., Baker, J., Seo, K., Lohmeyer, J., Mavers, M., Blazar, B. R., Garcia, C., Negrin, R. S. ELSEVIER SCIENCE INC. 2020: S59–S60
  • Molecular Imaging of Chimeric Antigen Receptor T Cells by ICOS-ImmunoPET Clinical cancer research: an official journal of the American Association for Cancer Research Alam*, I. S., Simonetta*, F. 2020: 1058–68

    Abstract

    Immunomonitoring of chimeric antigen receptor (CAR) T cells relies primarily on their quantification in the peripheral blood, which inadequately quantifies their biodistribution and activation status in the tissues. Noninvasive molecular imaging of CAR T cells by PET is a promising approach with the ability to provide spatial, temporal, and functional information. Reported strategies rely on the incorporation of reporter transgenes or ex vivo biolabeling, significantly limiting the application of CAR T-cell molecular imaging. In this study, we assessed the ability of antibody-based PET (immunoPET) to noninvasively visualize CAR T cells.After analyzing human CAR T cells in vitro and ex vivo from patient samples to identify candidate targets for immunoPET, we employed a syngeneic, orthotopic murine tumor model of lymphoma to assess the feasibility of in vivo tracking of CAR T cells by immunoPET using the 89Zr-DFO-anti-ICOS tracer, which we have previously reported.Analysis of human CD19-CAR T cells during activation identified the Inducible T-cell COStimulator (ICOS) as a potential target for immunoPET. In a preclinical tumor model, 89Zr-DFO-ICOS mAb PET-CT imaging detected significantly higher signal in specific bone marrow-containing skeletal sites of CAR T-cell-treated mice compared with controls. Importantly, administration of ICOS-targeting antibodies at tracer doses did not interfere with CAR T-cell persistence and function.This study highlights the potential of ICOS-immunoPET imaging for monitoring of CAR T-cell therapy, a strategy readily applicable to both commercially available and investigational CAR T cells.See related commentary by Volpe et al., p. 911.

    View details for DOI 10.1158/1078-0432.CCR-20-2770

    View details for PubMedCentralID PMC7887027