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A novel cancer vaccine strategy based on HLA-A*0201 matched allogeneic plasmacytoid dendritic cells.

Aspord C, Charles J, Leccia MT, Laurin D, Richard MJ, Chaperot L, Plumas J - PLoS ONE (2010)

Bottom Line: The development of effective cancer vaccines still remains a challenge.This semi-allogeneic pDC vaccine was more effective than conventional myeloid DC-based vaccines.These findings highlight HLA-A*0201 matched allogeneic pDCs as potent inducers of tumor immunity and provide a promising immunotherapeutic strategy to fight cancer.

View Article: PubMed Central - PubMed

Affiliation: Etablissement Français du Sang Rhone-Alpes, R&D Laboratory, La Tronche, France. carolineaspord@yahoo.com

ABSTRACT

Background: The development of effective cancer vaccines still remains a challenge. Despite the crucial role of plasmacytoid dendritic cells (pDCs) in anti-tumor responses, their therapeutic potential has not yet been worked out. We explored the relevance of HLA-A*0201 matched allogeneic pDCs as vectors for immunotherapy.

Methods and findings: Stimulation of PBMC from HLA-A*0201(+) donors by HLA-A*0201 matched allogeneic pDCs pulsed with tumor-derived peptides triggered high levels of antigen-specific and functional cytotoxic T cell responses (up to 98% tetramer(+) CD8 T cells). The pDC vaccine demonstrated strong anti-tumor therapeutic in vivo efficacy as shown by the inhibition of tumor growth in a humanized mouse model. It also elicited highly functional tumor-specific T cells ex-vivo from PBMC and TIL of stage I-IV melanoma patients. Responses against MelA, GP100, tyrosinase and MAGE-3 antigens reached tetramer levels up to 62%, 24%, 85% and 4.3% respectively. pDC vaccine-primed T cells specifically killed patients' own autologous melanoma tumor cells. This semi-allogeneic pDC vaccine was more effective than conventional myeloid DC-based vaccines. Furthermore, the pDC vaccine design endows it with a strong potential for clinical application in cancer treatment.

Conclusions: These findings highlight HLA-A*0201 matched allogeneic pDCs as potent inducers of tumor immunity and provide a promising immunotherapeutic strategy to fight cancer.

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Related in: MedlinePlus

The melanoma patients' tumor-specific T cells induced by the HLA-A*0201 matched allogeneic pDC line are highly cytotoxic and lyse autologous melanoma tumor cells.Tumor-specific T cells induced by the pDC line loaded with melanoma-derived peptides from melanoma patients' PBMC and TIL are highly functional in an HLA-A*0201 and antigen-specific manner. (A) Tetramer+ T cells specifically secreted IFNγ upon restimulation with T2 cells pulsed with the relevant peptide. Representative of 6 PBMC and 2 TIL samples. (B-D) T cells exhibited cytotoxicity towards allogeneic and autologous melanoma tumor cells and relevant peptide-pulsed T2 cells. T cells induced from PBMC or TIL were purified from days 15–20 cultures and used in a 51Cr release assay against peptide-loaded T2 cells, allogeneic and autologous melanoma tumor cells, and autologous CD45+ cells. (B) The PBMC sample shown was stimulated with MelA-loaded GEN cells. The TIL sample shown was stimulated with GEN cells loaded with a mixture of 4 peptides and developed a response towards MelA, GP100 and MAGE-3 antigens (see Figure 5C). Representative of 12 PBMC and 6 TIL samples. (C) Percentage of killing of autologous tumor cells compared to autologous CD45+ cells by TIL before and after stimulation. Representative of 6 TIL samples. (D) Comparison of the killing capacity between unstimulated and stimulated TIL on the indicated targets at a 60∶1 ratio. Mean+/-SEM of 6 TIL samples.
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pone-0010458-g006: The melanoma patients' tumor-specific T cells induced by the HLA-A*0201 matched allogeneic pDC line are highly cytotoxic and lyse autologous melanoma tumor cells.Tumor-specific T cells induced by the pDC line loaded with melanoma-derived peptides from melanoma patients' PBMC and TIL are highly functional in an HLA-A*0201 and antigen-specific manner. (A) Tetramer+ T cells specifically secreted IFNγ upon restimulation with T2 cells pulsed with the relevant peptide. Representative of 6 PBMC and 2 TIL samples. (B-D) T cells exhibited cytotoxicity towards allogeneic and autologous melanoma tumor cells and relevant peptide-pulsed T2 cells. T cells induced from PBMC or TIL were purified from days 15–20 cultures and used in a 51Cr release assay against peptide-loaded T2 cells, allogeneic and autologous melanoma tumor cells, and autologous CD45+ cells. (B) The PBMC sample shown was stimulated with MelA-loaded GEN cells. The TIL sample shown was stimulated with GEN cells loaded with a mixture of 4 peptides and developed a response towards MelA, GP100 and MAGE-3 antigens (see Figure 5C). Representative of 12 PBMC and 6 TIL samples. (C) Percentage of killing of autologous tumor cells compared to autologous CD45+ cells by TIL before and after stimulation. Representative of 6 TIL samples. (D) Comparison of the killing capacity between unstimulated and stimulated TIL on the indicated targets at a 60∶1 ratio. Mean+/-SEM of 6 TIL samples.

Mentions: We next investigated the relevance of this strategy in cancer patients. We tested the capacity of the peptide-pulsed pDC line to trigger ex-vivo tumor-specific responses from PBMC and tumor-infiltrating lymphocytes (TIL) isolated from stage I-V HLA-A*0201+ melanoma patients (Tables S1 and S2). Weekly stimulations of patients' PBMC with the pDC line pulsed either with MelA, GP100, TYR or MAGE-3 peptide led to the massive amplification of specific CD8+ T cells for at least 2 out of 4 melanoma antigens (Figures 5A and 5B). The tumor-specific tetramer+ CD8 T cell responses reached averages of 23% for MelA (range 0.4–62%), 1.2% for GP100 (range 0.05–3.5%), 0.3% for TYR (range 0.01–2.5%) and 0.2% for MAGE-3 (range 0.03–0.72%) after 20 days (baseline tetramer+ CD8+ T cells ranged from 0.02 to 0.03% at d0). One patient was excluded from the analysis due to an extremely intense response (85% tetramer+ T cells at day 14) towards TYR (Figure S5). Furthermore, repeated stimulations of patients'TIL with the pDC line pulsed with a mix of the 4 melanoma peptides led to the massive amplification of specific T cells for at least 3 antigens (Figures 5C and 5D). Tumor-specific tetramer+ CD8 T cell responses reached averages of 39% for MelA (range 12–59%), 7.4% for GP100 (range 0.2–24%), 0.3% for TYR (range 0.05–1.2%) and 1.1% for MAGE-3 (range 0.1–4.3%) after 20 days with baseline levels format day 0 1.7, 0.2, 0.05 and 0.3%, respectively. The tumor-specific T cells induced from both PBMC (Figure 6A) and TIL (not shown) secreted IFNγ when co-cultured with T2 cells loaded with the relevant but not with a control peptide. We obtained a mean of 42% of IFNγ+ tetramer+ CD8 T cells upon specific peptide restimulation compared to 11% in control conditions (n = 12, p = 0.0002, data not shown). Furthermore, these T cells exhibited a strong cytotoxic activity towards T2 cells loaded with relevant but not with control peptides and allogeneic melanoma tumor cells in an HLA-A*0201-restricted and antigen-specific manner (Figure 6B). Strikingly, after stimulation with the pDC line loaded with a mix of four melanoma-derived peptides, TIL acquired the ability to lyse autologous tumor cells but not CD45+ hematopoietic cells from the patient (Figure 6C). When comparing the killing capacity of unstimulated and stimulated TIL, the pDC line greatly enhanced their cytotoxic activity towards peptide-loaded T2 cells, semi-allogeneic melanoma tumor lines and autologous tumor cells (Figure 6D). Thus, the HLA- matched allogeneic pDC line loaded with melanoma-derived peptides induces multi-specific and highly functional ex-vivo T cell responses from stage I-IV melanoma patients.


A novel cancer vaccine strategy based on HLA-A*0201 matched allogeneic plasmacytoid dendritic cells.

Aspord C, Charles J, Leccia MT, Laurin D, Richard MJ, Chaperot L, Plumas J - PLoS ONE (2010)

The melanoma patients' tumor-specific T cells induced by the HLA-A*0201 matched allogeneic pDC line are highly cytotoxic and lyse autologous melanoma tumor cells.Tumor-specific T cells induced by the pDC line loaded with melanoma-derived peptides from melanoma patients' PBMC and TIL are highly functional in an HLA-A*0201 and antigen-specific manner. (A) Tetramer+ T cells specifically secreted IFNγ upon restimulation with T2 cells pulsed with the relevant peptide. Representative of 6 PBMC and 2 TIL samples. (B-D) T cells exhibited cytotoxicity towards allogeneic and autologous melanoma tumor cells and relevant peptide-pulsed T2 cells. T cells induced from PBMC or TIL were purified from days 15–20 cultures and used in a 51Cr release assay against peptide-loaded T2 cells, allogeneic and autologous melanoma tumor cells, and autologous CD45+ cells. (B) The PBMC sample shown was stimulated with MelA-loaded GEN cells. The TIL sample shown was stimulated with GEN cells loaded with a mixture of 4 peptides and developed a response towards MelA, GP100 and MAGE-3 antigens (see Figure 5C). Representative of 12 PBMC and 6 TIL samples. (C) Percentage of killing of autologous tumor cells compared to autologous CD45+ cells by TIL before and after stimulation. Representative of 6 TIL samples. (D) Comparison of the killing capacity between unstimulated and stimulated TIL on the indicated targets at a 60∶1 ratio. Mean+/-SEM of 6 TIL samples.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2864288&req=5

pone-0010458-g006: The melanoma patients' tumor-specific T cells induced by the HLA-A*0201 matched allogeneic pDC line are highly cytotoxic and lyse autologous melanoma tumor cells.Tumor-specific T cells induced by the pDC line loaded with melanoma-derived peptides from melanoma patients' PBMC and TIL are highly functional in an HLA-A*0201 and antigen-specific manner. (A) Tetramer+ T cells specifically secreted IFNγ upon restimulation with T2 cells pulsed with the relevant peptide. Representative of 6 PBMC and 2 TIL samples. (B-D) T cells exhibited cytotoxicity towards allogeneic and autologous melanoma tumor cells and relevant peptide-pulsed T2 cells. T cells induced from PBMC or TIL were purified from days 15–20 cultures and used in a 51Cr release assay against peptide-loaded T2 cells, allogeneic and autologous melanoma tumor cells, and autologous CD45+ cells. (B) The PBMC sample shown was stimulated with MelA-loaded GEN cells. The TIL sample shown was stimulated with GEN cells loaded with a mixture of 4 peptides and developed a response towards MelA, GP100 and MAGE-3 antigens (see Figure 5C). Representative of 12 PBMC and 6 TIL samples. (C) Percentage of killing of autologous tumor cells compared to autologous CD45+ cells by TIL before and after stimulation. Representative of 6 TIL samples. (D) Comparison of the killing capacity between unstimulated and stimulated TIL on the indicated targets at a 60∶1 ratio. Mean+/-SEM of 6 TIL samples.
Mentions: We next investigated the relevance of this strategy in cancer patients. We tested the capacity of the peptide-pulsed pDC line to trigger ex-vivo tumor-specific responses from PBMC and tumor-infiltrating lymphocytes (TIL) isolated from stage I-V HLA-A*0201+ melanoma patients (Tables S1 and S2). Weekly stimulations of patients' PBMC with the pDC line pulsed either with MelA, GP100, TYR or MAGE-3 peptide led to the massive amplification of specific CD8+ T cells for at least 2 out of 4 melanoma antigens (Figures 5A and 5B). The tumor-specific tetramer+ CD8 T cell responses reached averages of 23% for MelA (range 0.4–62%), 1.2% for GP100 (range 0.05–3.5%), 0.3% for TYR (range 0.01–2.5%) and 0.2% for MAGE-3 (range 0.03–0.72%) after 20 days (baseline tetramer+ CD8+ T cells ranged from 0.02 to 0.03% at d0). One patient was excluded from the analysis due to an extremely intense response (85% tetramer+ T cells at day 14) towards TYR (Figure S5). Furthermore, repeated stimulations of patients'TIL with the pDC line pulsed with a mix of the 4 melanoma peptides led to the massive amplification of specific T cells for at least 3 antigens (Figures 5C and 5D). Tumor-specific tetramer+ CD8 T cell responses reached averages of 39% for MelA (range 12–59%), 7.4% for GP100 (range 0.2–24%), 0.3% for TYR (range 0.05–1.2%) and 1.1% for MAGE-3 (range 0.1–4.3%) after 20 days with baseline levels format day 0 1.7, 0.2, 0.05 and 0.3%, respectively. The tumor-specific T cells induced from both PBMC (Figure 6A) and TIL (not shown) secreted IFNγ when co-cultured with T2 cells loaded with the relevant but not with a control peptide. We obtained a mean of 42% of IFNγ+ tetramer+ CD8 T cells upon specific peptide restimulation compared to 11% in control conditions (n = 12, p = 0.0002, data not shown). Furthermore, these T cells exhibited a strong cytotoxic activity towards T2 cells loaded with relevant but not with control peptides and allogeneic melanoma tumor cells in an HLA-A*0201-restricted and antigen-specific manner (Figure 6B). Strikingly, after stimulation with the pDC line loaded with a mix of four melanoma-derived peptides, TIL acquired the ability to lyse autologous tumor cells but not CD45+ hematopoietic cells from the patient (Figure 6C). When comparing the killing capacity of unstimulated and stimulated TIL, the pDC line greatly enhanced their cytotoxic activity towards peptide-loaded T2 cells, semi-allogeneic melanoma tumor lines and autologous tumor cells (Figure 6D). Thus, the HLA- matched allogeneic pDC line loaded with melanoma-derived peptides induces multi-specific and highly functional ex-vivo T cell responses from stage I-IV melanoma patients.

Bottom Line: The development of effective cancer vaccines still remains a challenge.This semi-allogeneic pDC vaccine was more effective than conventional myeloid DC-based vaccines.These findings highlight HLA-A*0201 matched allogeneic pDCs as potent inducers of tumor immunity and provide a promising immunotherapeutic strategy to fight cancer.

View Article: PubMed Central - PubMed

Affiliation: Etablissement Français du Sang Rhone-Alpes, R&D Laboratory, La Tronche, France. carolineaspord@yahoo.com

ABSTRACT

Background: The development of effective cancer vaccines still remains a challenge. Despite the crucial role of plasmacytoid dendritic cells (pDCs) in anti-tumor responses, their therapeutic potential has not yet been worked out. We explored the relevance of HLA-A*0201 matched allogeneic pDCs as vectors for immunotherapy.

Methods and findings: Stimulation of PBMC from HLA-A*0201(+) donors by HLA-A*0201 matched allogeneic pDCs pulsed with tumor-derived peptides triggered high levels of antigen-specific and functional cytotoxic T cell responses (up to 98% tetramer(+) CD8 T cells). The pDC vaccine demonstrated strong anti-tumor therapeutic in vivo efficacy as shown by the inhibition of tumor growth in a humanized mouse model. It also elicited highly functional tumor-specific T cells ex-vivo from PBMC and TIL of stage I-IV melanoma patients. Responses against MelA, GP100, tyrosinase and MAGE-3 antigens reached tetramer levels up to 62%, 24%, 85% and 4.3% respectively. pDC vaccine-primed T cells specifically killed patients' own autologous melanoma tumor cells. This semi-allogeneic pDC vaccine was more effective than conventional myeloid DC-based vaccines. Furthermore, the pDC vaccine design endows it with a strong potential for clinical application in cancer treatment.

Conclusions: These findings highlight HLA-A*0201 matched allogeneic pDCs as potent inducers of tumor immunity and provide a promising immunotherapeutic strategy to fight cancer.

Show MeSH
Related in: MedlinePlus