Figure 4.

Screening of peptides and evaluation of immune responses. Pre‐vaccination peripheral blood mononuclear cells (PBMC) and plasma were provided to examine cellular and humoral immune responses to 16 peptide panels in a HLA‐A24⁺ patient with advanced hormone refractory prostate cancer (HRPC). Namely, each of the 16 peptides was investigated for reactivity to prevaccination PBMC and plasma. PSA‐248, PTHrp‐102 and LCk‐486 peptides were recognized by both the cytotoxic T lymphocytes (CTL) (cut‐off level: 50 ng/mL of peptide‐specific interferon‐γ production by the peptide‐stimulated PBMC) and IgG (cut‐off level: 5 fluorescence intensity units of peptide‐specific IgG), whereas SART3‐109 peptide was recognized by IgG at the highest level. Therefore, these four peptides administered to the patient as vaccines. The same assays were conducted using the samples after the sixth vaccination to evaluate immune responses to the vaccinated peptides. The scale of the horizontal line was changed due to the augmentation of peptide‐specific CTL activity (two‐fold) and IgG reactive to the peptide (200‐fold).