ABSTRACT
Nanobodies (Nbs) have emerged as a promising class of biologics. Despite having marked physicochemical properties, Nbs are derived from camelids and may require humanization to improve translational potentials. By systematically analyzing the sequence and structural properties of Nbs, we found substantial framework diversities and revealed the key differences between Nbs and human immunoglobulin G antibodies. We identified conserved residues that may contribute to enhanced solubility, structural stability, and antigen binding, providing insights into Nb humanization. Based on big data analysis, we developed "Llamanade," an open-source software to facilitate rational humanization of Nbs. Using sequence as input, Llamanade can rapidly extract sequence features, model structures, and optimize solutions to humanize Nbs. Finally, we used Llamanade to successfully humanize a cohort of structurally diverse and potent SARS-CoV-2 neutralizing Nbs. Llamanade is freely available and will be easily accessible on a server to support the development of therapeutic Nbs into safe and effective trials.
Subject(s)
Antibodies, Monoclonal, Humanized/immunology , SARS-CoV-2/immunology , Single-Domain Antibodies/immunology , Antibodies, Monoclonal, Humanized/chemistry , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Computational Biology/methods , High-Throughput Nucleotide Sequencing , Single-Domain Antibodies/chemistryABSTRACT
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) initiates the infection process by binding to the viral cellular receptor angiotensin-converting enzyme 2 through the receptor-binding domain (RBD) in the S1 subunit of the viral spike (S) protein. This event is followed by virus-cell membrane fusion mediated by the S2 subunit, which allows virus entry into the host cell. Therefore, the SARS-CoV-2 S protein is a key therapeutic target, and prevention and treatment of coronavirus disease 2019 (COVID-19) have focused on the development of neutralizing monoclonal antibodies (nAbs) that target this protein. In this review, we summarize the nAbs targeting SARS-CoV-2 proteins that have been developed to date, with a focus on the N-terminal domain and RBD of the S protein. We also describe the roles that binding affinity, neutralizing activity, and protection provided by these nAbs play in the prevention and treatment of COVID-19 and discuss the potential to improve nAb efficiency against multiple SARS-CoV-2 variants. This review provides important information for the development of effective nAbs with broad-spectrum activity against current and future SARS-CoV-2 strains.
Subject(s)
Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , COVID-19 Drug Treatment , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Animals , Antibodies, Monoclonal, Humanized/chemistry , Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , Clinical Trials as Topic , Drug Approval , Drug Combinations , HumansABSTRACT
Among patients suffering from coronavirus disease 2019 (COVID-19) syndrome, one of the worst possible scenarios is represented by the critical lung damage caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-induced cytokine storm, responsible for a potentially very dangerous hyperinflammatory condition. Within such a context, interleukin-6 (IL-6) plays a key pathogenic role, thus being a suitable therapeutic target. Indeed, the IL-6-receptor antagonist tocilizumab, already approved for treatment of refractory rheumatoid arthritis, is often used to treat patients with severe COVID-19 symptoms and lung involvement. Therefore, the aim of this review article is to focus on the rationale of tocilizumab utilization in the SARS-CoV-2-triggered cytokine storm, as well as to discuss current evidence and future perspectives, especially with regard to ongoing trials referring to the evaluation of tocilizumab's therapeutic effects in patients with life-threatening SARS-CoV-2 infection.
Subject(s)
Antibodies, Monoclonal, Humanized/pharmacology , Antibodies, Monoclonal, Humanized/therapeutic use , COVID-19 Drug Treatment , Cytokine Release Syndrome/drug therapy , SARS-CoV-2/immunology , Antibodies, Monoclonal, Humanized/chemistry , COVID-19/complications , COVID-19/immunology , COVID-19/physiopathology , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/physiopathology , Humans , Interleukin-6/antagonists & inhibitors , Interleukin-6/physiologyABSTRACT
Cytokines are a family of proteins which play a major role in the regulation of the immune system and the development of several diseases, from rheumatoid arthritis to cancer and, more recently, COVID-19. Therefore, many efforts are currently being developed to improve therapy and diagnosis, as well as to produce inhibitory drugs and biosensors for a rapid, minimally invasive, and effective detection. In this regard, even more efficient cytokine receptors are under investigation. In this paper we analyze a set of IL-6 cytokine receptors, investigating their topological features by means of a theoretical approach. Our results suggest a topological indicator that may help in the identification of those receptors having the highest complementarity with the protein, a feature expected to ensure a stable binding. Furthermore, we propose and discuss the use of these receptors in an idealized experimental setup.