Unexpected abundance of HLA class II presented peptides in primary renal cell carcinomas.
OBJECTIVE
To elicit a long-lasting antitumor immune response, CD8+ and CD4+ T cells should be activated. We attempted to isolate HLA-DR-presented peptides directly from dissected solid tumors, in particular from renal cell carcinoma, to identify MHC class II ligands from tumor-associated antigens (TAA) for their use in peptide-based immunotherapy.


METHODS
Tumor specimens were analyzed by immunohistochemical staining for their HLA class II expression. HLA class II peptides were subsequently isolated and identified by mass spectrometry. Gene expression analysis was done to detect genes overexpressed in tumor tissue. Peptides from identified TAAs were used to induce peptide-specific CD4+ T-cell responses in healthy donors and in tumor patients.


RESULTS
In the absence of inflammation, expression of MHC class II molecules is mainly restricted to cells of the immune system. To our surprise, we were able to isolate and characterize hundreds of class II peptides directly from primary dissected solid tumors, especially from renal cell carcinomas, and from colorectal carcinomas and transitional cell carcinomas. Infiltrating leukocytes expressed MHC class II molecules and tumor cells, very likely under the influence of IFNgamma. Our list of identified peptides contains ligands from several TAAs, including insulin-like growth factor binding protein 3 and matrix metalloproteinase 7. The latter bound promiscuously to HLA-DR molecules and were able to elicit CD4+ T-cell responses.


CONCLUSIONS
Thus, our direct approach will rapidly expand the limited number of T-helper epitopes from TAAs for their use in clinical vaccination protocols.
Dengjel
Jörn
J
Immatics Biotechnologies GmbH, University of Tübingen, Germany.
Nastke
Maria-Dorothea
MD
Gouttefangeas
Cécile
C
Gitsioudis
Gitsios
G
Schoor
Oliver
O
Altenberend
Florian
F
Müller
Margret
M
Krämer
Björn
B
Missiou
Anna
A
Sauter
Martina
M
Hennenlotter
Jörg
J
Wernet
Dorothee
D
Stenzl
Arnulf
A
Rammensee
Hans-Georg
HG
Klingel
Karin
K
Stevanović
Stefan
S
D000951:Antigens, Neoplasm / Q000737:chemistry; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D000939:Epitopes / Q000737:chemistry; D015972:Gene Expression Regulation, Neoplastic; D006684:HLA-DR Antigens / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000378:metabolism; D007680:Kidney Neoplasms / Q000276:immunology* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry*; D012333:RNA, Messenger / Q000378:metabolism
D000951:Antigens, Neoplasm; D000939:Epitopes; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D012333:RNA, Messenger; D007371:Interferon-gamma