New gene expressed in prostate: a potential target for T cell-mediated prostate cancer immunotherapy
New gene expressed in prostate (NGEP) is a prostate-specific gene encoding either a small cytoplasmic protein (NGEP-S) or a larger polytopic membrane protein (NGEP-L). NGEP-L expression is detectable only in prostate cancer, benign prostatic hyperplasia and normal prostate. We have identified an HLA-A2 binding NGEP epitope (designated P703) which was used to generate T cell lines from several patients with localized and metastatic prostate cancer. These T cell lines were able to specifically lyse HLA-A2 and NGEP-expressing human tumor cells. NGEP-P703 tetramer binding assays demonstrated that metastatic prostate cancer patients had a higher frequency of NGEP-specific T cells when compared with healthy donors. Moreover, an increased frequency of NGEP-specific T cells was detected in the peripheral blood mononuclear cells of prostate cancer patients post-vaccination with a PSA-based vaccine, further indicating the immunogenicity of NGEP. These studies thus identify NGEP as a potential target for T cell-mediated immunotherapy of prostate cancer.
KeywordsNGEP Prostate cancer T cell Vaccine Epitopes
Cytotoxic T lymphocytes
Epstein Barr virus
Expressed sequence tag
Human leukocyte antigen-A2 allele
In vitro stimulation
Mean fluorescence intensity
New gene expressed in prostate
Peripheral blood mononuclear cells
Triad of costimulatory molecules (B7.1, ICAM-1, LFA-3)
The authors thank Bonnie Casey and Debra Weingarten for their editorial assistance in the preparation of this manuscript. This research was supported by the Intramural Research Program of the Center for Cancer Research, NCI, NIH.
Conflict of interest statement
There are no potential conflicts of interest.
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