1. Identification of HLA-ligands and T cell epitopes in SCLC
2. Characterization of T cell epitopes derived from newly-identified tumor antigens (Figure 1)
3. Evaluation of CD4+ and CD8+ T cell subsets and other immune cells within tumors and in the peripheral blood (Figure 2)
4. Effect of standard cancer therapies (e.g. chemotherapy or checkpoint blockade) on the immune system of cancer patients
To (1): our lab is part of the SFB1399 “Mechanisms of Drug Sensitivity and Resistance in Small Cell Lung Cancer” https://www.sfb1399.de.
Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer. It is initially highly sensitive to chemotherapy and radiotherapy, but in most cases, it relapsed with no effective treatment option left. SCLC-associated antigens that are recognized by T cells are largely unknown. In this project, we aim at identifying SCLC-associated T cell targets via mass spectrometry-based immunopeptidomics (Workflow in Figure 3). Our long-term objective is to define HLA-class I and class-II presented SCLC-antigens that could be used in immunotherapy approaches, e.g. peptide-based vaccination or cellular therapy.
1. CD4+ and CD8+ T cell induction during peptide-based vaccination: phenotype and (multi)function (Figures 4 & 5)
2. Correlation between immune response and clinical course
To (1): we are taking part to several early experimental vaccination trials in cancer patients. In an ongoing vaccine study for glioblastoma patients (NCT04842513, together with the neurosurgery Dept at the UKT), we are responsible for the full immune assessment of patients during vaccination. Aim of this in-depth immunomonitoring is to assess i) the immunogenicity of the peptides contained in the vaccine, ii) the quality of the vaccine-specific T cells, iii) the impact of further immune cell subsets on the T cell response.
1. In vitro effects of TLR ligands on immune cells and combination thereof
2. Immune monitoring of anti-tumor vaccines applied in combination with various adjuvants
Our in-house designed vaccines are applied together with a new TLR1/2 ligand which is used as adjuvant. We are analyzing the effects of this and further immune stimuli on immune cells. Objective is to characterize immune cell reactivity against adjuvants, quality of response across individuals, and to investigate whether in vitro immune activity measurement associates with immune T cell responses and clinical course in vaccinated patients
Our laboratory is equipped with high quality tools for immune monitoring (Figure 6). We are investigating different immune biomarkers associated with cancer and (response to) therapy. We are also interested in developing new “fit for purpose” antibody panels and assays for addressing the phenotype and function of immune cell subsets.
1. A new assay based on the detection of conformational changes of integrins after T-cell activation (Figure 7)
2. We are one of the founding members of the CIP/CIMT network: International immunoguiding activities within the CIP group
Our team is part of the iFIT excellence cluster https://www.medizin.uni-tuebingen.de/en-de/medizinische-fakultaet/forschung/ifit-exzellenzcluster. One of our mission within the iFIT is to provide tools and assays for addressing the impact of cancer immunotherapies on the immune system.
Figure 1 (click here to enlarge figure 1)
VITAL assay to assess the cytotoxic potential of tumor antigen specific CD8+ clones against peptide-loaded targets or transfectants expressing the relevant tumor antigen (Polychromatic flow cytometry). Laske et al. Cancer Immunol Res. 2013;190-200
Figure 2 (click here to enlarge figure 2)
Frequency of cells expressing inhibitory checkpoint receptors within non Treg CD4+ T cells or CD8+ T cells within TILs (RCC_T), autologous PBMCs (RCC_P), and age and gender-matched healthy donor PBMCs (HD_P). Mean and SD are shown; * p≤0.05 | ** p≤0.01 | *** p≤0.001). Zelba et al. Cancer Immunol Res 2019, 11:1891-1899
Figure 4 (click here to enlarge figure 4)
Induction of vaccine-specific CD4+ T cells in one patient with prostate carcinoma after peptide-based vaccination (IFN-γ ELISPOT assay with HLA-class II-binding peptides).
Figure 5 (click here to enlarge figure 5)
Polyfunctional analysis of vaccine-specific T cells in a cohort of 18 patients with prostate carcinoma. Bars represent means + 95% CI of specific CD4+ T cells expressing each of the five activation markers or all possible combinations thereof. One example of an intracellular cytokine staining is shown. Schuhmacher et al. Journal Immunother Cancer 2020, Nov 8 (2): e001157
Figure 7 (click here to enlarge figure 7)
Assessment of adhesion properties as a T cell monitoring tool. Following T-cell receptor-mediated stimulation, integrin (LFA-1) activation occurs rapidly through an “inside-out” signaling process which leads to an affinity increase and a clustering of membrane-bound integrins. These can be detected using fluorescent multimers of their ligand ICAM-1 (for detection of antigen-specific CD8+ T cells) or using the monoclonal antibody m24 (for detection of antigen-specific CD4+ and CD8+ T cells). Schöllhorn et al. Front Immunol 2021,12:626308