Prostein is a prostate tissue-specific
protein that is uniquely and abundantly expressed in normal and cancerous prostate tissues. Due to this expression profile, we examined the immunogenicity of
prostein as a potential
vaccine candidate for
prostate cancer. To determine the presence of CD8 T cells specific for naturally processed
prostein-derived
epitopes in healthy individuals, we developed and applied an in vitro stimulation protocol. Using this protocol, we identified CD8 T cells specific for
prostein in the peripheral blood of a male and a female donor.
Prostein-specific CD8 T cell clones specifically recognized
prostein-expressing targets, including prostate tumor cell lines expressing the relevant HLA alleles. CD8 T cell clones isolated from the male donor were significantly less effective in recognizing target cells compared to cells isolated from the female donor and appeared to recognize subdominant
epitopes. The identification of a
prostein-specific CD8 T cell repertoire supports the development of
prostein in vaccination strategies against
prostate cancer. Furthermore, the naturally processed
peptide epitopes identified provide tools for the development of
peptide-based vaccination strategies against
prostate cancer and for monitoring of
prostein-specific responses in vaccinated patients.