Enhancing CDC and ADCC of CD19 Antibodies by Combining Fc Protein-Engineering with Fc Glyco-Engineering

Abstract

Background: Native cluster of differentiation (CD) 19 targeting antibodies are poorly effective in triggering antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), which are crucial effector functions of therapeutic antibodies in cancer immunotherapy. Both functions can be enhanced by engineering the antibody’s Fc region by altering the amino acid sequence (Fc protein-engineering) or the Fc-linked glycan (Fc glyco-engineering). We hypothesized that combining Fc glyco-engineering with Fc protein-engineering will rescue ADCC and CDC in CD19 antibodies. Results: Four versions of a CD19 antibody based on tafasitamab’s V-regions were generated: a native IgG1, an Fc protein-engineered version with amino acid exchanges S267E/H268F/S324T/G236A/I332E (EFTAE modification) to enhance CDC, and afucosylated, Fc glyco-engineered versions of both to promote ADCC. Irrespective of fucosylation, antibodies carrying the EFTAE modification had enhanced C1q binding and were superior in inducing CDC. In contrast, afucosylated versions exerted an enhanced affinity to Fcγ receptor IIIA and had increased ADCC activity. Of note, the double-engineered antibody harboring the EFTAE modification and lacking fucose triggered both CDC and ADCC more efficiently. Conclusions: Fc glyco-engineering and protein-engineering could be combined to enhance ADCC and CDC in CD19 antibodies and may allow the generation of antibodies with higher therapeutic efficacy by promoting two key functions simultaneously.

Immune Complex Vaccine Strategies to Combat HIV-1 and Other Infectious Diseases

“…However, improved V1V2 and V3 immunogenicity detected upon IC immunization in our studies may also be attributed to the Fc function, even though evidence for this phenomenon is still developing. Our early study examining different types of APCs treated with ICs versus un-complexed gp120 did not show the influence of Fc-enhanced uptake [ 59 , 72 , 73 ]. Rather, gp120 complexed with high-affinity CD4bs-specific mAbs was more stable and resistant to proteolytic degradation, resulting in lower gp120 antigen presentation of MHC-II-restricted CD4 T cells [ 52 , 71 ].…”

“…To better incorporate the Fc contribution to the IC vaccine strategy, future studies are planned to construct IC vaccines using mAbs with a rhesus macaque Fc IgG fragment in order to evaluate their immunogenicity in this non-human primate model. In addition, IC vaccines’ improvement may be accomplished by engineering mAbs with Fc mutations or glycan modifications that enhance FcR and complement binding [ 15 , 73 ].…”

Anti-CD19 monoclonal antibodies for the treatment of relapsed or refractory B-cell malignancies: a narrative review with focus on diffuse large B-cell lymphoma

“…Over the past three decades, several anti-CD19 monoclonal antibodies have been evaluated for the treatment of B-cell malignancies (Katz and Herishanu 2014 ; Zalevsky et al 2009 ; Narkhede and Tafasitamab 2020 ; Roßkopf et al 2020 ). Initial results with unmodified or drug-conjugated anti-CD19 antibodies were modest, and research efforts subsequently focused on antibody optimisation and strategies to potentiate immune effector cell activity (Horst et al 2020 ; Katz and Herishanu 2014 ; Narkhede and Tafasitamab 2020 ).…”

“…The cytotoxic effects of monoclonal antibodies are mediated by their Fc regions, which are therefore critical for therapeutic efficacy (Horst et al 2020 ). Engineering of the Fc domain, via modification of the Fc glycosylation profile (glyco-engineering) or site-directed mutagenesis of the Fc domain (protein engineering), is a novel approach to antibody modification (Horst et al 2020 ; Narkhede and Tafasitamab 2020 ; Roßkopf et al 2020 ; Kellner et al 2017 ). ADCC and ADCP responses are induced when the Fc domain binds to Fc gamma receptors (FcγR) that are expressed on a variety of effector cells, including natural killer (NK) cells and macrophages (Horst et al 2020 ).…”

Special Issue: The Role of Complement in Cancer Immunotherapy

“…Rosskopf and colleagues have made substantial advances in the area of IgG engineering by modifying mAbs to enhance their potential to more effectively target and destroy tumor cells [9]. They have made use of an FDA-approved CD19 mAb (tafasitamab) which has modest activity in inducing antibody-dependent cellular cytotoxicity (ADCC) but does not activate complement or induce CDC.…”