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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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Uptake of tumor cells by DCs. Myeloma cells were labeled with dye (PKH26) and either stained with anti–syndecan-1 antibody (mAb), isotype control antibody, or left unstained. Tumor cells were irradiated (3 Gy) just before coculture with dye (PKH67) labeled DCs at 4°C or 37°C, and the percent of double-positive DCs (top right of each panel) analyzed by flow cytometry.
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fig1: Uptake of tumor cells by DCs. Myeloma cells were labeled with dye (PKH26) and either stained with anti–syndecan-1 antibody (mAb), isotype control antibody, or left unstained. Tumor cells were irradiated (3 Gy) just before coculture with dye (PKH67) labeled DCs at 4°C or 37°C, and the percent of double-positive DCs (top right of each panel) analyzed by flow cytometry.

Mentions: We used 2 HLA A2.1-negative cell lines (cag, arp) expressing both MAGE-3 and NY-ESO-1 (cag cells) or MAGE-3 alone (arp cells), as sources of defined C-T antigens to elicit HLA A*0201-restricted peptide-specific T cells in vitro. Both cell lines expressed high levels of syndecan-1, and binding of anti-syndecan antibody did not induce apoptosis (data not shown). The myeloma cells were induced to undergo apoptosis by high dose (30 Gy) γ irradiation, necrosis by repeated freeze thaw cycles, or treated with anti–syndecan-1 antibody/isotype, as live, low dose (3 Gy) γ-irradiated cells. Myeloma cells were then fed to immature DCs from healthy donors. Phagocytosis studies performed using tumor cells and DCs labeled with different color fluorochromes indicated that label from anti–syndecan-1, isotype control antibody treated, or untreated tumor cells was taken up by DCs upon 2–20 h of coculture at 37°C (but not at 4°C) with similar efficiency (Fig. 1) . Uptake of tumor cells was also verified using confocal microscopy after staining for tumor cells with an antibody to the CT-7 tumor antigen (data not shown). Therefore the coating with anti–syndecan-1 antibody was not required for tumor cell uptake in this system.


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)

Uptake of tumor cells by DCs. Myeloma cells were labeled with dye (PKH26) and either stained with anti–syndecan-1 antibody (mAb), isotype control antibody, or left unstained. Tumor cells were irradiated (3 Gy) just before coculture with dye (PKH67) labeled DCs at 4°C or 37°C, and the percent of double-positive DCs (top right of each panel) analyzed by flow cytometry.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196013&req=5

fig1: Uptake of tumor cells by DCs. Myeloma cells were labeled with dye (PKH26) and either stained with anti–syndecan-1 antibody (mAb), isotype control antibody, or left unstained. Tumor cells were irradiated (3 Gy) just before coculture with dye (PKH67) labeled DCs at 4°C or 37°C, and the percent of double-positive DCs (top right of each panel) analyzed by flow cytometry.
Mentions: We used 2 HLA A2.1-negative cell lines (cag, arp) expressing both MAGE-3 and NY-ESO-1 (cag cells) or MAGE-3 alone (arp cells), as sources of defined C-T antigens to elicit HLA A*0201-restricted peptide-specific T cells in vitro. Both cell lines expressed high levels of syndecan-1, and binding of anti-syndecan antibody did not induce apoptosis (data not shown). The myeloma cells were induced to undergo apoptosis by high dose (30 Gy) γ irradiation, necrosis by repeated freeze thaw cycles, or treated with anti–syndecan-1 antibody/isotype, as live, low dose (3 Gy) γ-irradiated cells. Myeloma cells were then fed to immature DCs from healthy donors. Phagocytosis studies performed using tumor cells and DCs labeled with different color fluorochromes indicated that label from anti–syndecan-1, isotype control antibody treated, or untreated tumor cells was taken up by DCs upon 2–20 h of coculture at 37°C (but not at 4°C) with similar efficiency (Fig. 1) . Uptake of tumor cells was also verified using confocal microscopy after staining for tumor cells with an antibody to the CT-7 tumor antigen (data not shown). Therefore the coating with anti–syndecan-1 antibody was not required for tumor cell uptake in this system.

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