Abstract
The present work was designed to compare two mechanisms of cellular recognition based on Ab specificity: firstly, when the anti-HER2 mAb trastuzumab bridges target cells and cytotoxic lymphocytes armed with a Fc receptor (ADCC) and, secondly, when HER2 positive target cells are directly recognized by cytotoxic lymphocytes armed with a chimeric antigen receptor (CAR). To compare these two mechanisms, we used the same cellular effector (NK-92) and the same signaling domain (FcεRIγ). The NK-92 cytotoxic cell line was transfected with either a FcγRIIIa-FcεRIγ (NK-92(CD16)) or a trastuzumab-based scFv-FcεRIγ chimeric receptor (NK-92(CAR)). In vitro, the cytotoxic activity against HER2 positive target cells after indirect recognition by NK-92(CD16) was always inferior to that observed after direct recognition by NK-92(CAR). In contrast, and somehow unexpectedly, in vivo, adoptive transfer of NK-92(CD16) + trastuzumab but not of NK-92(CAR) induced tumor regression. Analysis of the in vivo xenogeneic system suggested that the human CH2-CH3 IgG2 used as a spacer in our construct was able to interact with the FcR present at the cell surface of the few NSG-FcR+ remaining immune cells. This interaction, leading to blockage of the NK-92(CAR) in the periphery of the engrafted tumor cells, stresses the critical role of the composition of the spacer domain.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Adoptive Transfer
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Animals
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Antineoplastic Agents / chemistry
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Antineoplastic Agents / pharmacology*
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Cetuximab / chemistry
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Cetuximab / pharmacology
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Cytotoxicity, Immunologic / drug effects*
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GPI-Linked Proteins / chemistry
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GPI-Linked Proteins / genetics
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GPI-Linked Proteins / immunology
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Gene Expression
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Humans
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Immunoglobulin G / chemistry
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Immunoglobulin G / genetics
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Immunoglobulin G / immunology*
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K562 Cells
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Mice
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Mice, Inbred NOD
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Mice, SCID
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Receptor, ErbB-2 / chemistry
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Receptor, ErbB-2 / genetics
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Receptor, ErbB-2 / immunology
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Receptors, IgE / chemistry
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Receptors, IgE / genetics
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Receptors, IgE / immunology
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Receptors, IgG / chemistry
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Receptors, IgG / genetics
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Receptors, IgG / immunology*
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / immunology*
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Single-Chain Antibodies / chemistry
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Single-Chain Antibodies / genetics
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Single-Chain Antibodies / immunology
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T-Lymphocytes, Cytotoxic / cytology
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T-Lymphocytes, Cytotoxic / immunology*
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Transduction, Genetic
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Trastuzumab / chemistry
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Trastuzumab / pharmacology
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Xenograft Model Antitumor Assays
Substances
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Antineoplastic Agents
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FCGR3A protein, human
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FCGR3B protein, human
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FcepsilonRI gamma-chain, human
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GPI-Linked Proteins
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Immunoglobulin G
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Receptors, IgE
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Receptors, IgG
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Recombinant Fusion Proteins
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Single-Chain Antibodies
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ERBB2 protein, human
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Receptor, ErbB-2
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Trastuzumab
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Cetuximab