Preclinical T Cell Research

The Research Group "GMP & T Cell Therapy" has recently initiated a collaboration project with physicians from the Heidelberg University Hospital, Myeloma Center (Dept. of Hematology), focused on the identification of myeloma specific T cells and subsequent TCR isolation, in order establish of TCR transduced T cells for adoptive therapy.
Furthermore, we investigate miRNAs affecting the expression of immune checkpoint molecules in human tumor cell lines as well as the susceptibility of murine melanoma cell lines to cognate CTL recognition. As miRNAs are also involved in the functional polarization of tumor associated macrophages (TAMs), we are developing nanoparticle-based delivery systems for targeted delivery of M1-polarizing small non coding (nc)RNAs into immunosuppressive M2-like TAMs.
It has been shown that irradiation of a primary tumor can induce regression of untreated tumors located outside of the irradiation field. This rarely, but consistently occurring "abscopal effect" can be reinforced upon combination of irradiation therapy with administration of antibodies against immunological checkpoint inhibitors. We thus compare the effects of classical photon irradiation to the very novel method of heavy ion beam irradiation based on carbon ions. This irradiation modality is hallmarked by its focused release of destructive energy precisely within the targeted tumor, thus sparing healthy tissue from collateral side effects.

Adoptive T cell transfer (AT) is presently considered as most successful treatment strategy in cancer therapy, provided that the transferred T cells recognize mutated epitopes, so called neo-epitopes presented by the tumor cells. In fact, the greatest challenge of adoptive T cell therapy is the definition of tumor-specific targets and hence the direct identification of tumor-specific T cells and their T cell receptor (TCR). In this collaborative project, we aim at the direct identification of myeloma specific T cells isolated from the bone marrow of patients. Containing both, tumor cells and T cells, the bone marrow aspirates can be used to screen for autologous, tumor-specific T cells. We are utilizing the Berkeley Lights „Lightning™ Optofluidic System", a benchtop instrument that allows individual analysis of several thousand cells within separate nano-pens on one chip. The interaction between sorted myeloma cells and individual T cells is analyzed through quantification of cytokines secreted by reactive T cells. In the next step, T cells thus determined will be isolated from the chip for TCR sequencing and DNA vectors coding for the identified TCRs will be generated. Finally, the reactivity of these TCRs with the autologous myeloma cells will be tested. Ultimately, such strategies could be applied to generate autologous, TCR-transgenic T cells for adoptive T cell therapy of multiple myeloma patients.

miRNAs are endogenous, small non-coding RNAs post-transcriptionally repressing gene expression by a mechanism known as RNA interference (RNAi). Thus, miRNAs can act as oncogenes or as tumor suppressors, respectively, depending on the gene encoded by the mRNA they target. It is well established that the expression of miRNAs is deregulated in tumor cells. Upon miRNA library screening we could identify miRNAs altering the susceptibility of melanoma cells to CTL mediated killing.

Furthermore, we have identified miRNAs which down- or (indirectly) upregulate immune checkpoint inhibitor molecules thereby affecting the immunosuppressive tumor micro-milieu. Presently, the target genes of these miRNAs are being identified as they might provide starting points for the development of novel strategies to enhance immunological therapies against solid tumors. Theresa Kordaß has presented results on this project at the virtual CIMT meeting 2021. The presentation can be watched here.

Tumor associated macrophages (TAMs) are highlighted by functional plasticity enabling them to shift between various functional phenotypes ranging from M2-like macrophages with immunosuppressive function to immuno-stimulatory M1-like TAMs. Since the amount of intra-tumoral TAMs is generally dominated by M2-like macrophages, we propose to repolarize M2 like TAMs through targeted introduction of M1-polarizing small non-coding (nc) miRNAs i.e. miRNAs and siRNAs. For this purpose, two ncRNA delivery systems are currently being developed: i) ncRNA conjugated nano-particles tagged with a M2 targeting structure and ii) viral delivery systems based on engineered measles virus strains recombinantly expressing the polarizing ncRNAs. The ncRNA delivery systems generated will be tested in vitro on M2-like bone marrow derived macrophages (BMDMs) and subsequently on TAMs isolated from tumor bearing mice. Finally, the therapeutic effect of the M2-targeting ncRNA shuttle systems will be analyzed in tumor bearing mice after systemic administration.

In this project, the radio-immunogenic effects of photon and carbon ion irradiation are compared. First, both irradiation types are tested on various tumor cell lines in vitro. Therefore, alterations in the expression of immunomodulatory molecules in response to different irradiation regimens (various doses, fractionated or as single dose) are analyzed by qPCR and on protein level by FACS. Next, the abscopal effects induced among non-irradiated tumors upon irradiation of the primary tumor combined with systemic application of monoclonal antibodies against immune checkpoint inhibitors are investigated. Thus, the immune infiltrate of irradiated tumors and of non-irradiated regressing lesions will be analyzed in close detail applying FACS, qPCR, tetramer staining and singe cell sequencing. Boosting the abscopal effect by optimized radio-immunotherapy strategies might to improve the therapy of metastatic lesions making the application of chemotherapeutic drugs dispensable.

A complete and actualized listing of publications of the Eichmüller lab can be found on a separate website. PDF files are available on request for personal usage (see website).

(in alphabetical order)

Prof. Dr. Dr. Christine Engeland (University Witten/Herdecke)
Prof. Dr. Hartmut Goldschmidt / Dr. Mirco Friedrich (Dept. of Hematology, University Hospital Heidelberg)
Prof. Dr. Jessica Hassel (Dept. of Dermatology, University Hospital Heidelberg)
Dr. Richard Harbottle (DKFZ, F160)
Prof. Dr. Barbara Seliger (Inst. for Medical Immunology, University Hospital Halle)
Prof. Dr. Rainer König (Jena University Hospital, Jena)
Prof. Dr. Magnus von Knebel-Döberitz (DKFZ, F210)
Prof. Dr. Dirk Jäger (NCT Heidelberg)
Prof. Dr. Martin Müller (DKFZ, F035)
Prof. Dr. Rienk Offringa (DKFZ, D200)
Prof. Dr. Michael Platten & Dr. Isabel Poschke (DKFZ, D170, G808)
Prof. Dr. Stefan Rieken (University Hospital Göttingen, Radiology)
Dr. Andreas Schmidt (Proteona, Köln and Singapur)
Prof. Dr. Dr. Guy Ungerechts (DKFZ, F230)