Long-peptide vaccination with driver gene mutations in p53 and Kras induces cancer mutation-specific effector as well as regulatory T cell responses

Jasmin Quandt; Christoph Schlude; Michael Bartoschek; Rainer Will; Angel Cid-Arregui; Sebastian Schölch; Christoph Reissfelder; Jürgen Weitz; Martin Schneider; Stefan Wiemann; Frank Momburg; Philipp Beckhove

doi:10.1080/2162402X.2018.1500671

Long-peptide vaccination with driver gene mutations in p53 and Kras induces cancer mutation-specific effector as well as regulatory T cell responses

Oncoimmunology. 2018 Sep 21;7(12):e1500671. doi: 10.1080/2162402X.2018.1500671. eCollection 2018.

Authors

Jasmin Quandt^{1

2}, Christoph Schlude¹, Michael Bartoschek^{1

3}, Rainer Will⁴, Angel Cid-Arregui^{1

5}, Sebastian Schölch^{6

7}, Christoph Reissfelder^{6

7}, Jürgen Weitz⁸, Martin Schneider⁶, Stefan Wiemann^{4

9}, Frank Momburg^{1

10}, Philipp Beckhove^{1

11}

Affiliations

¹ Department of Translational Immunology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany.
² Knapp Research Center, Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, IL, USA.
³ Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden.
⁴ Genomics and Proteomics Core Facility, German Cancer Research Center (DKFZ), Heidelberg, Germany.
⁵ Targeted Tumor Vaccines Group, Clinical Cooperation Unit Applied Tumor Immunity, German Cancer Research Center (DKFZ), Heidelberg, Germany.
⁶ Department of Visceral Surgery, University Hospital Heidelberg, Heidelberg, Germany.
⁷ Department of Surgery, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
⁸ Department of Visceral, Thoracic, and Vascular Surgery, Medizinische Fakultaet an der TU-Dresden, Dresden, Germany.
⁹ Division Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
¹⁰ Antigen Presentation and T/NK Cell Activation Group, Clinical Cooperation Unit Applied Tumor Immunity, German Cancer Research Center (DKFZ), Heidelberg, Germany.
¹¹ Regensburg Center for Interventional Immunology (RCI), University Regensburg and Department of Hematology-Oncology, Internal Medicine III, University Hospital Regensburg, Regensburg, Germany.

Abstract

Mutated proteins arising from somatic mutations in tumors are promising targets for cancer immunotherapy. They represent true tumor-specific antigens (TSAs) as they are exclusively expressed in tumors, reduce the risk of autoimmunity and are more likely to overcome tolerance compared to wild-type (wt) sequences. Hence, we designed a panel of long peptides (LPs, 28-35 aa) comprising driver gene mutations in TP35 and KRAS frequently found in gastrointestinal tumors to test their combined immunotherapeutic potential. We found increased numbers of T cells responsive against respective mutated and wt peptides in colorectal cancer patients that carry the tested mutations in their tumors than patients with other mutations. Further, active immunization of HLA(-A2/DR1)-humanized mice with mixes of the same mutated LPs yielded simultaneous, polyvalent CD8⁺/CD4⁺ T cell responses against the majority of peptides. Peptide-specific T cells possessed a multifunctional cytokine profile with CD4⁺ T cells showing a T_H1-like phenotype. Two mutated peptides (Kras[G12V], p53[R248W]) induced significantly higher T cell responses than corresponding wt sequences and comprised HLA-A2/DR1-restricted mutated epitopes. However, vaccination with the same highly immunogenic LPs strongly increased systemic regulatory T cells (T_reg) numbers in a syngeneic sarcoma model over-expressing these mutated protein variants and resulted in accelerated tumor outgrowth. In contrast, tumor outgrowth was delayed when vaccination was directed against tumor-intrinsic Kras/Tp53 mutations of lower immunogenicity. Conclusively, we show that LP vaccination targeting multiple mutated TSAs elicits polyvalent, multifunctional, and mutation-specific effector T cells capable of targeting tumors. However, the success of this therapeutic approach can be hampered by vaccination-induced, TSA-specific T_regs.

Keywords: Kras; Long-peptide vaccination; Treg; common driver mutations; p53; regulatory T cells; tumor mutation specific T cell responses; tumor-specific mutated antigens.