Center for Molecular Medicine Cologne


Chimeric antigen receptor (CAR) engineered T cells showed spectacular efficacy in the treatment of hematologic malignancies by recognizing tumor cells with pre-defined antibody specificity. Immune-suppression and/or deviation by the tumor microenvironment and down-regulation or losing antigen expression, however, are major hurdles of CAR T cell therapy resulting in tumor relapse by antigen-loss cancer cells as seen by the increasing number of CD19-negative relapses after treatment with CD19 CAR T cells. Moreover, primarily antigen-heterogeneous tumors are generally hard to target by CAR T cells as it is frequently the case in solid cancers. To address the situation we developed new CAR T cell strategies to modulate the CAR T cell response against antigen heterologous tumor cells:

  • (i) Reprogramming the CAR T cell response by IL12-CAR T cells. We inserted a functionally active, single-chain p40-p35 variant of IL12 into the extracellular moiety of the CAR while the CAR remains capable to bind cognate antigen through the scFv and to signal through the CAR intracellular domains upon antigen engagement. T cells engineered with such IL12-CAR specifically engaged the CAR cognate antigen through the anti-tumor scFv, produced pro-inflammatory cytokines and eliminated antigen-positive tumor cells. Strikingly, cytotoxic T cells with IL12-CAR predominantly gained a CD8+CD56+CD62Lhigh phenotype, down-regulated Th2 and upregulated NK and CIK cell associated genes compared to conventional CAR T cells. Functionally, IL12-CAR T cells gained antigen-independent lytic activities in addition to antigen-dependent cytolysis making antigen-heterogeneous tumors accessible to an IL12-CAR T cell attack. IL12-CAR is the first prototype of a hybrid receptor that specifically combines the antigen-redirected activity of a CAR with the T cell maturating activity of a cytokine to tune the T cell function towards the elimination of antigen-heterogeneous tumors.
  • (ii) Reprogramming the CAR T cell response by interfering with the CD30-CD30L-axis with bispecific anti-CD30-tumorantigen-CARs. We targeted CD30 during the initiation of a CAR redirected T cell response by an anti-CD30 immunotoxin or anti-CD30 CAR T cells. Assuming that the CD30-CD30L interaction drives freshly activated T cells to limit their immune response by shifting to Th2 reactivity, we designed a CAR that in addition to a cancer recognition domain also harbors a CD30 targeting domain to disrupt the CD30-CD30L interaction on freshly activated lymphocytes. T cells with such combined tumor targeting and “T cell instructing” CAR showed improved cytotoxic activity against CD30 negative, non-hematopoietic cancer cells in vitro and in a mouse model. The data draws a novel concept in adoptive cell therapy based on providing two capacities by a single CAR, one being cancer cell targeting and the other, T cell de-repressing. This is all in order to improve anti-tumor immunity.
  • Barden M, Holzinger A, Velas L, Mezosi-Csaplar M, Szoor A, Vereb G, Schutz GJ, Hombach AA, and Abken H (2023). CAR and TCR form individual signaling synapses and do not cross-activate, however, can co-operate in T cell activation. Front Immunol 14, 1110482. doi:10.3389/fimmu.2023.1110482.
  • Hombach AA, Ambrose C, Lobb R, Rennert P, and Abken H (2023). A CD19-Anti-ErbB2 scFv Engager Protein Enables CD19-Specific CAR T Cells to Eradicate ErbB2(+) Solid Cancer. Cells 12. doi:10.3390/cells12020248.
  1. Hombach, A., Barden, M., Hannappel, L., Chmielewski, M., Rappl, G., Sachinidis, A., and Abken, H. (2021). IL12 integrated into the CAR exodomain convertsCD8+ T cells to poly-functional NK-like cells with superior killing of antigen-loss tumors. Mol Ther, S1525-0016(21)00518–9.
  2. Ambrose, C., Su, L., Wu, L., Dufort, F.J., Sanford, T., Birt, A., Hackel, B.J., Hombach, A., Abken, H., Lobb, R.R., et al. (2021). Anti-CD19 CAR T cells potently redirected to kill solid tumor cells. PLoS One 16, e0247701.
  3. Patasic, L., Seifried, J., Bezler, V., Kaljanac, M., Schneider, I.C., Schmitz, H., Tondera, C., Hartmann, J., Hombach, A., Buchholz, C.J., et al. (2020). Designed Ankyrin Repeat Protein (DARPin) to target chimeric antigen receptor (CAR)-redirected T cells towards CD4+ T cells to reduce the latent HIV+ cell reservoir. Med Microbiol Immunol 209, 681–691.
  4. Hombach, A.A., Geumann, U., Günther, C., Hermann, F.G., and Abken, H. (2020). IL7-IL12 Engineered Mesenchymal Stem Cells (MSCs) Improve A CAR T Cell Attack Against Colorectal Cancer Cells. Cells 9.
  5. Hombach, A.A., Rappl, G., and Abken, H. (2019). Blocking CD30 on T Cells by a Dual Specific CAR for CD30 and Colon Cancer Antigens Improves the CAR T Cell Response against CD30- Tumors. Mol. Ther. 27, 1825–1835.
  6. Aleksandrova, K., Leise, J., Priesner, C., Melk, A., Kubaink, F., Abken, H., Hombach, A., Aktas, M., Essl, M., Bürger, I., et al. (2019). Functionality and Cell Senescence of CD4/ CD8-Selected CD20 CAR T Cells Manufactured Using the Automated CliniMACS Prodigy® Platform. Transfus Med Hemother 46, 47–54.
  7. Golumba-Nagy, V., Kuehle, J., Hombach, A.A., and Abken, H. (2018). CD28-ζ CAR T Cells Resist TGF-β Repression through IL-2 Signaling, Which Can Be Mimicked by an Engineered IL-7 Autocrine Loop. Mol. Ther. 26, 2218–2230.
  8. Hombach, A.A., and Abken, H. (2017). Most Do, but Some Do Not: CD4+CD25- T Cells, but Not CD4+CD25+ Treg Cells, Are Cytolytic When Redirected by a Chimeric Antigen Receptor (CAR). Cancers (Basel) 9.
  9. Hombach, A.A., and Abken, H. (2017). Shared target antigens on cancer cells and tissue stem cells: go or no-go for CAR T cells? Expert Rev Clin Immunol 13, 151–155.
  10. Martyniszyn, A., Krahl, A.-C., André, M.C., Hombach, A.A., and Abken, H. (2017). CD20-CD19 Bispecific CAR T Cells for the Treatment of B-Cell Malignancies. Hum. Gene Ther. 28, 1147–1157.
  11. Faitschuk, E., Nagy, V., Hombach, A.A., and Abken, H. (2016). A dual chain chimeric antigen receptor (CAR) in the native antibody format for targeting immune cells towards cancer cells without the need of an scFv. Gene Ther. 23, 718–726.
  12. Hombach, A.A., Görgens, A., Chmielewski, M., Murke, F., Kimpel, J., Giebel, B., and Abken, H. (2016). Superior Therapeutic Index in Lymphoma Therapy: CD30(+) CD34(+) Hematopoietic Stem Cells Resist a Chimeric Antigen Receptor T-cell Attack. Mol. Ther. 24, 1423–1434.
  13. Faitschuk, E., Hombach, A.A., Frenzel, L.P., Wendtner, C.-M., and Abken, H. (2016). Chimeric antigen receptor T cells targeting Fc μ receptor selectively eliminate CLL cells while sparing healthy B cells. Blood 128, 1711–1722.
  • Hombach A, Barden M, Hannappel L, Chmielewski M, Rappl G,Sachinidis A, and Abken H (2021). IL12 integrated into the CAR exodomain convertsCD8(+) T cells to poly-functional NK-like cells with superior killing of antigen-loss tumors. Mol Ther. doi:10.1016/j.ymthe.2021.10.011.
  • Hombach AA, Geumann U, Gunther C, Hermann FG, and Abken H (2020). IL7-IL12 Engineered Mesenchymal Stem Cells (MSCs) Improve A CAR T Cell Attack Against Colorectal Cancer Cells. Cells9. doi:10.3390/cells9040873.
                                                                                                                                                      • Patasic L, Seifried J, Bezler V, Kaljanac M, Schneider IC, Schmitz H, Tondera C, Hartmann J, Hombach A, Buchholz CJ, Abken H, Konig R, and Cichutek K (2020). Designed Ankyrin Repeat Protein (DARPin) to target chimeric antigen receptor (CAR)-redirected T cells towards CD4(+) T cells to reduce the latent HIV(+) cell reservoir. Med Microbiol Immunol209, 681-691. doi:10.1007/s00430-020-00692-0.
                                                                                                                                                      Dr. Andreas Hombach CMMC Cologne
                                                                                                                                                      Dr. Andreas Hombach

                                                                                                                                                      Clinic I of Internal Medicine I Lab. for Tumor Genetics and Cellular Immunotherapy - CMMC Research Building

                                                                                                                                                      CMMC - PI - assoc. RG 29

                                                                                                                                                      +49 221 478 89639

                                                                                                                                                      Clinic I of Internal Medicine I Lab. for Tumor Genetics and Cellular Immunotherapy - CMMC Research Building

                                                                                                                                                      Robert-Koch-Straße 21

                                                                                                                                                      50931 Cologne

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                                                                                                                                                      Publications on PubMed

                                                                                                                                                      Publications - Andreas Hombach

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