Enhanced Natural Killer Cell Binding and Activation by Low-Fucose IgG1 Antibody Results in Potent Antibody-Dependent Cellular Cytotoxicity Induction at Lower Antigen Density

Abstract

Purpose: Recent studies have revealed that fucose removal from the oligosaccharides of human IgG1 antibodies results in a significant enhancement of antibody-dependent cellular cytotoxicity (ADCC) via improved IgG1 binding to Fc;RIIIa. In this report, we investigated the relationship between enhanced ADCC and antigen density on target cells using IgG1 antibodies with reduced fucose.Experimental Design: Using EL4 cell-derived transfectants with differential expression levels of exogenous human CC chemokine receptor 4 or human CD20 as target cells, ADCC of fucose variants of chimeric IgG1 antibodies specific for these antigens were measured. We further investigated IgG1 binding to natural killer (NK) cells and NK cell activation during ADCC induction to elucidate the mechanism by which low-fucose IgG1 induces ADCC upon target cells with low antigen expression.Results: Low-fucose IgG1s showed potent ADCC at low antigen densities at which their corresponding highfucose counterparts could not induce measurable ADCC. The quantitative analysis revealed that fucose depletion could reduce the antigen amount on target cells required for constant degrees of ADCC induction by 10-fold for CC chemokine receptor 4 and 3-fold for CD20. IgG1 binding to NK cells was increased by ligating IgG1 with clustered antigen, especially for low-fucose IgG1. Up-regulation of an activation marker, CD69, on NK cells, particularly the CD56 dim subset, in the presence of both the antibody and target cells was much greater for the low-fucose antibodies.Conclusions: Our data showed that fucose removal from IgG1 could reduce the antigen amount required for ADCC induction via efficient recruitment and activation of NK cells.

The availability of glucose to CHO cells affects the intracellular lipid-linked oligosaccharide distribution, site occupancy and the N-glycosylation profile of a monoclonal antibody

“…Increasing in terminal galactosylation and decreasing in fucosylation in the Fc region of IgG resulted in an elevation in antibody-dependent cellmediated cytotoxicity, which is the most common mode of action of Mabs in vitro and in vivo (Niwa et al, 2005;Werner et al, 2007). The expression of N-acetylglucosaminyltransferase III, an enzyme, which transfers 1,4-GlcNAc to a core, mannose (Man) residue, results in increasing potency of the ADCC, and suggests the need for lower therapeutic doses in vivo (Shinkawa et al, 2002).…”

The role of Fc gamma receptors in the activity of immunomodulatory antibodies for cancer

“…The extent of effector function triggered by antibody binding has been shown in a number of studies to be strongly influenced by the level of target antigen expression [37,38], with antibodies directed against both human CCR4 and CD20 failing to elicit in vitro ADCC against human tumor cell lines expressing anything less than 10 4 antigen molecules per cell and reaching optimal activity only in the presence of 10 5 -10 6 antigen molecules [37]. Many of the targets for immunomodulatory antibodies are expressed at low to undetectable levels on resting, peripheral immune cells, but are up-regulated significantly in the presence of pro-inflammatory stimuli, such as those present in the tumor microenvironment.…”

The CCR4 as a novel-specific molecular target for immunotherapy in Hodgkin lymphoma

“…[8][9][10][11] Most importantly, based on the promising results in our previous work, [8][9][10][12][13][14][15] we are currently conducting a phase I clinical trial of anti-CCR4 mAb in patients with CCR4-positive T-cell lymphomas (ClinicalTrials.gov Identifier: NCT00355472). We here extend our earlier KM2760 study on CCR4-positive T-cell neoplasms to classical HL in order to develop a novel treatment strategy for patients with refractory HL.…”