A prostate stem cell antigen-derived peptide immunogenic in HLA-A24- prostate cancer patients.
BACKGROUND
We attempted to identify prostate stem cell antigen (PSCA)-derived peptides immunogenic in HLA-A24+ prostate cancer patients.


METHODS
Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with each of three different PSCA-derived peptides, which were prepared based on the HLA-A24 binding motif, and their peptide-specific and HLA-A24-restricted anti-tumor responses were examined. Plasma levels of immunoglobulin G (IgG) against PSCA peptides were measured by enzyme-linked immunosorbent assay (ELISA).


RESULTS
Among three PSCA peptides, the PSCA 76-84 peptide most effectively induced peptide-specific cytotoxic T lymphocytes (CTLs) from PBMCs of HLA-A24+ prostate cancer patients. Cytotoxicity was dependent on peptide-specific and CD8+ T cells. The PSCA 76-84 peptide-stimulated PBMCs showed a significant level of cytotoxicity against prostate cancer cells in an HLA-A24-restricted manner. IgG reactive to the PSCA 76-84 peptide was detected in half of patients.


CONCLUSIONS
The PSCA 76-84 peptide should be considered for use in clinical trials of immunotherapy for HLA-A24+ patients.
Matsueda
Satoko
S
Department of Immunology, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
Yao
Akihisa
A
Ishihara
Yuki
Y
Ogata
Rika
R
Noguchi
Masanori
M
Itoh
Kyogo
K
Harada
Mamoru
M
D000951:Antigens, Neoplasm; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D015234:HLA-A Antigens / Q000276:immunology*; D059871:HLA-A24 Antigen; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007167:Immunotherapy; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D009363:Neoplasm Proteins / Q000032:analysis*; D010455:Peptides; D011471:Prostatic Neoplasms / Q000276:immunology* / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D058851:GPI-Linked Proteins; D015234:HLA-A Antigens; D059871:HLA-A24 Antigen; D007074:Immunoglobulin G; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human; D010455:Peptides