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Cytotoxic T lymphocytes that recognize decameric peptide sequences of retinoblastoma binding protein 1 (RBP-1)
1Department of Biotechnology Sciences, John Wayne Cancer Institute, Santa Monica, CA 90404, USA.
Abstract:
Retinoblastoma binding protein 1 (RBP-1) is a 143-kDa nuclear phosphoprotein that promotes cell growth by inhibiting the product of retinoblastoma tumour suppressor gene (pRB). We recently found that RBP-1 contains KASIFLK, a heptameric peptide (250-256) recognized by human antibodies and overexpressed by breast cancer cells. In the present study, we demonstrate that human T-cells stimulated with RBP-1 decameric peptides containing KASIFLK can kill human breast cancer cells. These decamers, GLQKASIFLK (247-256) and KASIFLKTRV (250-259), have anchor motifs for both HLA-A2 and HLA-A3. Peripheral blood lymphocytes from 41 normal donors were stimulated by these peptides in culture media containing 15 IU ml(-1) interleukin-2, 25 IU ml(-1) interleukin-7 and 500 IU ml(-1) granulocyte-macrophage colony-stimulating factor. Cytotoxic activity of the T-cells was assessed against autologous B lymphoblastoid cells pulsed with each peptide. Stimulation by GLQKASIFLK generated specific cytotoxic T lymphocyte (CTL) lines from HLA-A2, A3 donors, HLA-A2 donors and HLA-A3 donors. Stimulation with KASIFLKTRV generated specific CTL lines from HLA-A2 donors. No HLA-A2-, A3 CTL line showed specific cytotoxicity against these target cells. These CTL lines were also cytotoxic against HLA-A2 and HLA-A3 breast cancer cells but not against normal fibroblastoid cell lines, normal epidermal cell lines, or a melanoma cell line. RBP-1 peptide antigens may be of clinical significance as a potential peptide vaccine against human breast cancer.
Insights
Retinoblastoma binding protein 1 (RBP-1) peptides stimulate human T-cells to kill breast cancer cells. These RBP-1 peptides show potential as a novel peptide vaccine for breast cancer treatment.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Retinoblastoma binding protein 1 (RBP-1) is a nuclear phosphoprotein that promotes cell growth.
- RBP-1 contains a heptameric peptide (KASIFLK) overexpressed in breast cancer cells.
- This peptide is recognized by human antibodies.
Purpose of the Study:
- To investigate the potential of RBP-1 peptides in cancer immunotherapy.
- To determine if RBP-1 peptides can stimulate T-cells to target and kill breast cancer cells.
Main Methods:
- Human peripheral blood lymphocytes were stimulated with RBP-1 decameric peptides (GLQKASIFLK and KASIFLKTRV) containing the KASIFLK motif.
- Interleukin-2, -7, and granulocyte-macrophage colony-stimulating factor were used in culture media.
- Cytotoxic activity of stimulated T-cells was assessed against peptide-pulsed autologous B lymphoblastoid cells and cancer cell lines.
Main Results:
- Specific cytotoxic T lymphocyte (CTL) lines were generated from HLA-A2 and/or HLA-A3 donors using GLQKASIFLK and KASIFLKTRV peptides.
- These CTL lines demonstrated specific cytotoxicity against HLA-A2 and HLA-A3 breast cancer cells.
- No significant cytotoxicity was observed against normal fibroblastoid or epidermal cell lines, or a melanoma cell line.
Conclusions:
- RBP-1 derived peptides can elicit a specific T-cell mediated anti-cancer immune response.
- These peptides hold promise as a potential peptide vaccine for treating human breast cancer.