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Antitumor monoclonal antibodies enhance cross-presentation ofcCellular antigens and the generation of myeloma-specific killer T cells by dendritic cells.

Dhodapkar KM, Krasovsky J, Williamson B, Dhodapkar MV - J. Exp. Med. (2002)

Bottom Line: The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood.Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells.Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Tumor Immunology and Immunotherapy, The Rockefeller University, New York, NY 10021, USA.

ABSTRACT
The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood. Here we show that coating myeloma cells with anti-syndecan-1 antibody promotes cross-presentation of cellular antigens by dendritic cells (DCs) to autologous T cells from healthy donors. The tumor cells treated with anti-syndecan-1 or isotype-matched control antibody were fed to HLA-mismatched monocyte-derived immature DCs. Tumor cell-loaded mature DCs induced a strong CD8(+) T cell response that was specific for the cancer-testis (C-T) antigens expressed in the tumor. The CD8(+) T cells killed peptide-pulsed targets, as well as myeloma tumor cells. Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells. This enhanced cross-presentation was not due to enhanced tumor cell uptake or to DC maturation. When mixtures of NY-Eso-1-positive and -negative myeloma cells were captured by DCs, the anti-syndecan-1 antibody had to be on the NY-Eso-1-positive cells to elicit NY-Eso-1-specific response. Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies. Targeting of mAb-coated tumors to DCs may contribute to the efficacy of tumor-reactive mAb and offers a new strategy for immunotherapy.

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Generation of tumor-specific killer T cells. (A) Generation of killer T cells using peptide-pulsed or tumor cell–loaded DCs. T cells from experiment in Fig. 3 A were tested for killing of T2 cells pulsed with 10 μM HLA A*0201-restricted MAGE3/ NY-Eso-1 peptide or HLA A*0201-positive (U266) or -negative (ark) myeloma cells, at a E/T ratio of 20:1, with a 5 h 51Cr release assay. Lysis of K562 cells (as control) was <10% (data not shown). (B) Summary of experiments on three donors using DCs loaded with dying (apoptotic/necrotic) or antibody-treated (anti–syndecan-1 mAb/isotype) myeloma cells (arp cells: MAGE-3 +ve, NY-Eso-1 –ve).
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fig4: Generation of tumor-specific killer T cells. (A) Generation of killer T cells using peptide-pulsed or tumor cell–loaded DCs. T cells from experiment in Fig. 3 A were tested for killing of T2 cells pulsed with 10 μM HLA A*0201-restricted MAGE3/ NY-Eso-1 peptide or HLA A*0201-positive (U266) or -negative (ark) myeloma cells, at a E/T ratio of 20:1, with a 5 h 51Cr release assay. Lysis of K562 cells (as control) was <10% (data not shown). (B) Summary of experiments on three donors using DCs loaded with dying (apoptotic/necrotic) or antibody-treated (anti–syndecan-1 mAb/isotype) myeloma cells (arp cells: MAGE-3 +ve, NY-Eso-1 –ve).

Mentions: T cells elicited using mAb tumor–loaded DCs efficiently killed not only peptide pulsed targets, but also killed tumor cells HLA matched to DCs (Fig. 4 A and B). In contrast, T cells elicited using peptide-pulsed DCs only killed peptide pulsed targets, but not HLA A2.1+ myeloma cells expressing these antigens (Fig. 4 A). The killing of tumor cells was inhibited by preincubation of targets with anti-MHC I, but not anti-MHC II (data not shown), consistent with the response being due to CD8+ T cells and specific for MHC class I binding peptides. Again, the generation of tumor-specific killer T cells was higher and more consistent using DCs loaded with antibody- coated cells (3/3 donors) than using dying cell loaded DCs (2/3 donors; Fig. 4 B). Thus DCs loaded with antibody-coated tumor cells are superior to peptide pulsed DCs or DCs loaded with dying cells to stimulate tumor-specific killer T cells.


Antitumor monoclonal antibodies enhance cross-presentation ofcCellular antigens and the generation of myeloma-specific killer T cells by dendritic cells.

Dhodapkar KM, Krasovsky J, Williamson B, Dhodapkar MV - J. Exp. Med. (2002)

Generation of tumor-specific killer T cells. (A) Generation of killer T cells using peptide-pulsed or tumor cell–loaded DCs. T cells from experiment in Fig. 3 A were tested for killing of T2 cells pulsed with 10 μM HLA A*0201-restricted MAGE3/ NY-Eso-1 peptide or HLA A*0201-positive (U266) or -negative (ark) myeloma cells, at a E/T ratio of 20:1, with a 5 h 51Cr release assay. Lysis of K562 cells (as control) was <10% (data not shown). (B) Summary of experiments on three donors using DCs loaded with dying (apoptotic/necrotic) or antibody-treated (anti–syndecan-1 mAb/isotype) myeloma cells (arp cells: MAGE-3 +ve, NY-Eso-1 –ve).
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Related In: Results  -  Collection

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fig4: Generation of tumor-specific killer T cells. (A) Generation of killer T cells using peptide-pulsed or tumor cell–loaded DCs. T cells from experiment in Fig. 3 A were tested for killing of T2 cells pulsed with 10 μM HLA A*0201-restricted MAGE3/ NY-Eso-1 peptide or HLA A*0201-positive (U266) or -negative (ark) myeloma cells, at a E/T ratio of 20:1, with a 5 h 51Cr release assay. Lysis of K562 cells (as control) was <10% (data not shown). (B) Summary of experiments on three donors using DCs loaded with dying (apoptotic/necrotic) or antibody-treated (anti–syndecan-1 mAb/isotype) myeloma cells (arp cells: MAGE-3 +ve, NY-Eso-1 –ve).
Mentions: T cells elicited using mAb tumor–loaded DCs efficiently killed not only peptide pulsed targets, but also killed tumor cells HLA matched to DCs (Fig. 4 A and B). In contrast, T cells elicited using peptide-pulsed DCs only killed peptide pulsed targets, but not HLA A2.1+ myeloma cells expressing these antigens (Fig. 4 A). The killing of tumor cells was inhibited by preincubation of targets with anti-MHC I, but not anti-MHC II (data not shown), consistent with the response being due to CD8+ T cells and specific for MHC class I binding peptides. Again, the generation of tumor-specific killer T cells was higher and more consistent using DCs loaded with antibody- coated cells (3/3 donors) than using dying cell loaded DCs (2/3 donors; Fig. 4 B). Thus DCs loaded with antibody-coated tumor cells are superior to peptide pulsed DCs or DCs loaded with dying cells to stimulate tumor-specific killer T cells.

Bottom Line: The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood.Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells.Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Tumor Immunology and Immunotherapy, The Rockefeller University, New York, NY 10021, USA.

ABSTRACT
The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood. Here we show that coating myeloma cells with anti-syndecan-1 antibody promotes cross-presentation of cellular antigens by dendritic cells (DCs) to autologous T cells from healthy donors. The tumor cells treated with anti-syndecan-1 or isotype-matched control antibody were fed to HLA-mismatched monocyte-derived immature DCs. Tumor cell-loaded mature DCs induced a strong CD8(+) T cell response that was specific for the cancer-testis (C-T) antigens expressed in the tumor. The CD8(+) T cells killed peptide-pulsed targets, as well as myeloma tumor cells. Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells. This enhanced cross-presentation was not due to enhanced tumor cell uptake or to DC maturation. When mixtures of NY-Eso-1-positive and -negative myeloma cells were captured by DCs, the anti-syndecan-1 antibody had to be on the NY-Eso-1-positive cells to elicit NY-Eso-1-specific response. Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies. Targeting of mAb-coated tumors to DCs may contribute to the efficacy of tumor-reactive mAb and offers a new strategy for immunotherapy.

Show MeSH
Related in: MedlinePlus