Abstract
AbstractCD4+ T cell responses are crucial for inducing and maintaining effective anticancer immunity, and the identification of human leukocyte antigen class II (HLA-II) cancer-specific epitopes is key to the development of potent cancer immunotherapies. In many tumor types, and especially in glioblastoma (GBM), HLA-II complexes are hardly ever naturally expressed. Hence, little is known about immunogenic HLA-II epitopes in GBM. With stable expression of the class II major histocompatibility complex transactivator (CIITA) coupled to a detailed and sensitive mass spectrometry–based immunopeptidomics analysis, we here uncovered a remarkable breadth of the HLA-ligandome in HROG02, HROG17, and RA GBM cell lines. The effect of CIITA expression on the induction of the HLA-II presentation machinery was striking in each of the three cell lines, and it was significantly higher compared with interferon gamma (IFNɣ) treatment. In total, we identified 16,123 unique HLA-I peptides and 32,690 unique HLA-II peptides. In order to genuinely define the identified peptides as true HLA ligands, we carefully characterized their association with the different HLA allotypes. In addition, we identified 138 and 279 HLA-I and HLA-II ligands, respectively, most of which are novel in GBM, derived from known GBM-associated tumor antigens that have been used as source proteins for a variety of GBM vaccines. Our data further indicate that CIITA-expressing GBM cells acquired an antigen presenting cell-like phenotype as we found that they directly present external proteins as HLA-II ligands. Not only that CIITA-expressing GBM cells are attractive models for antigen discovery endeavors, but also such engineered cells have great therapeutic potential through massive presentation of a diverse antigenic repertoire.
Highlights
CD4+ T cell responses are crucial for inducing and maintaining effective anticancer immunity, and the identification of human leukocyte antigen class II (HLA-II) cancer-specific epitopes is key to the development of potent cancer immunotherapies
Little is known about immunogenic human leukocyte antigens molecules (HLA)-II epitopes in GBM
The identification of HLA-II cancer-specific epitopes is key to the development of potent cancer immunotherapies
Summary
CD4+ T cell responses are crucial for inducing and maintaining effective anticancer immunity; in glioblastoma and many solid tumors, HLA-II complexes are hardly ever naturally expressed. With stable expression of the class II major histocompatibility complex transactivator (CIITA) coupled to a detailed immunopeptidomics, we uncovered a remarkable breadth of the HLA-ligandome in three glioblastoma cell lines and identified many cancerassociated ligands with implications for the development of cancer immunotherapies. CD4+ T cell responses are crucial for inducing and maintaining effective anticancer immunity, and the identification of human leukocyte antigen class II (HLA-II) cancer-specific epitopes is key to the development of potent cancer immunotherapies. CIITA-expressing GBM cells express very high levels of HLA-II complexes and naturally present a large repertoire of known HLA-I ligands, but most importantly, of novel HLA-II ligands derived from shared and immunogenic tumor-associated antigens (TAAs). While future work will be required to test the therapeutic potential of each of these antigens, as the antigenicity of CIITA-glioblastoma tumors is greatly enhanced, we propose that vaccination approaches with CIITA-expressing GBM cells could be effective, potentially by sensitizing the tumors to other immunotherapies
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.