RT Journal Article
SR Electronic
T1 Novel mechanisms of action contributing to benralizumab's potent anti-eosinophilic activity
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 2004306
DO 10.1183/13993003.04306-2020
VO 59
IS 3
A1 Rania Dagher
A1 Varsha Kumar
A1 Alan M. Copenhaver
A1 Sandra Gallagher
A1 Mahboobe Ghaedi
A1 Jonathan Boyd
A1 Paul Newbold
A1 Alison A. Humbles
A1 Roland Kolbeck
YR 2022
UL http://erj.ersjournals.com/content/59/3/2004306.abstract
AB Background Benralizumab is a humanised, anti-interleukin-5 receptor α monoclonal antibody with anti-eosinophilic activity. Lack of fucose (afucosylation) increases its affinity to CD16a and significantly enhances antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells. Although benralizumab proved clinically efficacious in clinical trials for patients with severe asthma and hypereosinophilic syndrome, in-depth characterisation of its anti-eosinophilic mechanisms of action remains elusive.Methods Here, we further investigated the mechanisms involved in benralizumab's anti-eosinophilic activities by employing relevant primary human autologous cell co-cultures and real-time-lapse imaging combined with flow cytometry.Results In the presence of NK cells, benralizumab induced potent eosinophil apoptosis as demonstrated by the upstream induction of Caspase-3/7 and upregulation of cytochrome c. In addition, we uncovered a previously unrecognised mechanism whereby benralizumab can induce eosinophil phagocytosis/efferocytosis by macrophages, a process called antibody-dependent cellular phagocytosis. Using live cell imaging, we unravelled the stepwise processes leading to eosinophil apoptosis and uptake by activated macrophages. Through careful observations of cellular co-culture assays, we identified a novel role for macrophage-derived tumour necrosis factor (TNF) to further enhance benralizumab-mediated eosinophil apoptosis through activation of TNF receptor 1 on eosinophils. TNF-induced eosinophil apoptosis was associated with cytochrome c upregulation, mitochondrial membrane depolarisation and increased Caspase-3/7 activity. Moreover, activated NK cells were found to amplify this axis through the secretion of interferon-γ, subsequently driving TNF expression by macrophages.Conclusions Our data provide deeper insights into the timely appearance of events leading to benralizumab-induced eosinophil apoptosis and suggest that additional mechanisms may contribute to the potent anti-eosinophilic activity of benralizumab in vivo. Importantly, afucosylation of benralizumab strongly enhanced its potency for all mechanisms investigated.New insights explaining the potent anti-eosinophilic activity of benralizumab, an anti-IL-5Rα afucosylated monoclonal antibody with enhanced depleting potency in patients with severe eosinophilic inflammation https://bit.ly/3yUnsnn