Monoclonal Antibodies in COVID-19: History
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Monoclonal antibodies (MAbs) are one of the emerging therapeutic agents efficacious for treating infectious diseases such as COVID-19. They are one of the fastest-growing pharmaceuticals and are considered to be highly specific in their action. MAbs are lab-grown antibodies that specifically target the pathogen, causing its destruction immediately.

  • monoclonal antibodies
  • patent reviews
  • COVID-19
  • therapeutic application

1. Introduction

Until now, the disease has infected millions of people and killed a significant number of them. The virus belongs to the large family of beta-coronavirus and is named as Severe Acute Respiratory Syndrome Coronavirus two (SARS-CoV-2). Other important members of this class of virus are the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and SARS-CoV-1 [1]. The virus is being mutated at regular intervals, and some of the variants have been found to be more virulent and resistant to certain vaccines. Major parts of the world are still suffering from the spread of the infection and are causing an unrepairable severe economic slowdown due to repeated lockdowns [2].

In over 80% of patients, the disease is characterized by mild symptoms, such as cough, fever, and difficult breathing. However, in aged people, immunocompromised and co-morbid patients, the infection can cause severe pneumonia, pulmonary edema, acute respiratory syndrome, sepsis, multiorgan failure and death [3]. Symptomatic diagnosis of COVID-19 is difficult and is considered inaccurate due to the resemblance to a common seasonal viral infection. Suspected individuals should be diagnosed with real-time polymerase chain reaction (RT-PCR) by collecting samples from nasal and/or throat swabs to confirm the infection [4].

SARS-CoV-2 is a beta-coronavirus containing RNA as the nuclear component. The genetic sequencing indicated that the virus has 80% similarity with SARS-CoV-1 and 96% with bat coronavirus. The outer surface of the virus contains three major components: spike (S) glycoproteins, envelope (E) and film (M) protein. The S protein binds to angiotensin-converting enzyme-2 (ACE2) located on the surface of host cells and initiates the process of infection [5]. The S protein was identified to contain two functional subunits that assist in the interaction with the host cell. The S 1 subunits contain four core domains named S 1A , S 1B , S1C, and S1D, which are responsible for attaching the virus to the host. The S 2 subunit then assists in fusion of the virus with the cellular membrane of host cells [6].

Monoclonal antibodies (MAbs) are one of the emerging therapeutic agents efficacious for treating infectious diseases such as COVID-19. They are one of the fastest-growing pharmaceuticals and are considered to be highly specific in their action [7]. MAbs are lab-grown antibodies that specifically target the pathogen, causing its destruction immediately. Normally, MAbs are produced by B cells in patients after several days of infection. They can be isolated from recovered individuals, can be generated in the laboratory by immunizing animals and can also be constructed by molecular engineering in the laboratory [8]. Modern technology helps in the identification of specific antibodies after their production, isolation, characterization, and growth in laboratory conditions. MAbs are gaining popularity among both physicians and patients because these agents easily meet the three important requirements for being a drug: safety, efficacy and quality [9]. The MAbs currently tested against COVID-19 can either neutralize the virus action or decrease the inflammatory process due to infection. Some of them, such as bamlanivimab, sarilumab and siltuximab, have received emergency use authorization. Side effects, unpredictable bioavailability and the emergence of resistant strains are the important limitations of MAbs tested against COVID-19 [10].

2. Methods

MAbs was conducted using internet search engines, such as PubMed, Google Scholar, Science Direct and WIPO (The World Intellectual Property Organization) websites by using key words such as ‘Monoclonal’, ‘Antibodies’, ‘COVID-19’, ‘Patent Information’, ‘Clinical Trials’, ‘Mechanism’ and ‘Adverse Reactions’ [11]. It included clinical trials conducted from the beginning of 2020, coinciding with reports of the identification of the SARS-CoV-2 genome, until the end of July 2021. The search resulted in more than 1500 total articles. However, only 88 articles were selected for the present study based on the inclusion criteria. The authors independently reviewed the titles, abstracts, and text of the articles. The information, such as English language, study center, number of subjects, study design, study protocol, dose, duration, route of administration, ethical approval, statistical methods, and biochemical estimations, were considered critical parameters for evaluating the content and were considered the inclusion criteria [12]. Only those articles containing the required information were selected for the analysis. The patent information retrieved from the WIPO is categorized separately in a table given in discussion section.

3. Description of Monoclonal Antibodies

Multifunctional immunoglobulins/antibodies are considered multifunctional since they show numerous cellular and humoral reactions to antigens. They are produced by the immune system and are usually polyclonal, i.e., produced by different B lymphocytes. In terms of antigen binding capacity, these antibodies behave slightly differently from one another [13]. Technological innovations have made it possible to identify one single B cell that can be stimulated to produce one specific type of antibody called a monoclonal antibody. Therefore, MAbs are homogenous preparations of antibodies obtained from single B cells and have an identical protein sequence. These antibodies possess a common antigen recognition site, affinity, biological interaction, and similar physiological effects [14].

This technique is commonly used in cancer chemotherapy. The antibodies formed in the patients and having the capacity to infiltrate the tumor are identified. They are isolated from the regional lymph node and the tissues can be harvested to produce specific antibodies [15]. Peripheral blood, bone marrow and lymphoid tissues can also be used for the extraction of antibodies. MAbs isolated from this technique were found to be useful in the treatment of HIV. Bamlanivimab is a new MAb that has been tested against SARS-CoV-2 infection and is synthesized by isolating from recovered patients [16].

In this way, these agents were specifically targeted to treat the disease. Anti-CFRP receptor antibodies (Erenumab), anti-fibroblast growth factor 23 (FGF 23) antibodies (Burosumab), and anti-Willebrand factor antibodies (Caplacizumab) are some of the important MAbs that have revolutionized the approach to treating disease [17][18][19]. Research is also in progress to isolate human antibodies from patients who have recovered from Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV). Attempts have been made to grow these antibodies in the lab [20]. Concurrent use of MAbs with other therapeutic agents, such as chemotherapy, radiotherapy, hormonal replacement, and other biological agents is also being tested, and the results suggest that such a combination has the potential to be an effective treatment [17]. The conjugation of antibodies with other therapeutic agents with the help of advanced technology is reported to provide novelty in the management of diseases. Some of the conjugates being tested include immuno-cytokines, antibody-drug conjugates, antibody-radionuclide conjugates, bispecific antibodies, immunoliposomes and chimeric antigen receptor T cell therapy [17][21].

Antigenization is a newer approach for delivering a vaccine molecule with the help of MAbs. The specific sequence/fragment of the antigen can be incorporated into one of the several binding domains of MAbs [22]. The MAbs, being specific in their target, deliver the vaccine molecule inside the cell. The vaccine molecule will then activate the cells to produce immunogenic antigens, leading to the production of antibodies. However, this technology is still in the preclinical stage, where bovine herpes virus B cell epitopes have been successfully grafted onto a bovine immunoglobulin molecule [23].

4. Patent Search

A patent literature review revealed more than 100 different MAbs for SARS-CoV-2 registered by pharmaceutical companies. The technique to produce these MAbs has been patented. We selected 88 such patents based on their content and these were reviewed and analyzed for patent status, technological innovations, research conducted, mechanism of action, side effects, contraindications/precautions, and any special description about the agents. According to the patent analysis, approximately 30% of published patents are registered by US-based companies, with the remainder registered by Chinese (10%) and UK (9%) companies [24]. Patent information about the articles retrieved from search engines, such as Google Scholar, Pubmed and Science Direct are represented in Table 1 , while those retrieved from WIPO are mentioned in Table 2 . WIPO is an intergovernmental organization that basically protects the intellectual property rights of the signatory bodies and functions as per the international treaties [25]. The data collected from this website is separately indicated in Table 2 .

Table 1. Important MAb patents registered for treating COVID-19 [26].
Sl No. Patent Number Description Target Antigen Organization
1 WO2009128963 Method of preparation and use of human monoclonal antibodies for neutralizing the action of SARS-CoV. Spike protein Institute for Research in Biomedicine
2 WO2007044695 Information about monoclonal antibodies used for diagnosis and treatment of SARS-coronavirus-associated disease and evaluating the efficacy of vaccine or anti-SARS agent. Spike protein Dana-Farber Cancer Institute
3 CN1911963 Technique of production and use of a monoclonal antibody against severe acute respiratory syndrome coronavirus. RBD of S protein Chinese Academy of Sciences
4 WO2006095180 Human monoclonal antibodies to treat the infection in patients caused by SARS-associated coronavirus. S2 protein Ultra Biotech Ltd.; University of California
5 WO2006086561 Production and therapeutic application of neutralizing monoclonal antibodies against severe acute respiratory syndrome-associated coronavirus. Spike protein New York Blood Center, Inc.
6 WO2005007671 Production of monoclonal antibodies against the peptides derived from SARS virus E2, N-terminal-alpha helix or C-terminal-alpha helix of virus. Spike protein Epitomics, Inc
7 CN1673231 Synthesis of a monoclonal antibody targeted against N proteins of SARS coronavirus and testing its clinical use in the treatment of SARS infections. Spike protein Chinese Academy of Sciences
8 US20060240551 Production and clinical evaluation of monoclonal antibodies that neutralize the pathogenesis of severe acute respiratory syndrome-associated Coronavirus. Spike protein New York Blood Center, Inc.
9 WO2005054469 Production of anti-SARS-coronavirus monoclonal antibodies for diagnosis and treatment and for testing its use in vaccine preparation. Spike protein Health Canada
10 US20050069869 New human monoclonal antibodies against spike (S) proteins of SARS and testing their diagnostic and therapeutic application. Spike protein University of Massachusetts
11 CN1566155 Library-driven production of human monoclonal antibodies against SARS virus caused infection. S, N, and M Proteins Igcon Therapeutics Co., Ltd.; Genetastix
12 CN1660912 Production and testing the use of a new class of monoclonal antibodies against human interleukin. Il-8 Ye Qingwei

Note: RBD—Receptor binding domains, Il—Interleukins, S, N, M proteins—Spike, Nucleocapsid, Membrane proteins.

Table 2. List of important patent applications currently filed (2021) for MAbs against COVID-19 in WIPO [27].
Patent Number Patent Information Target Antigen Principle Investigators
WO 2021158521 A1 20210812 Neutralizing monoclonal antibody variants targeting SARS CoV-2 for use in diagnosis, prophylaxis, and treatment of SARS CoV-2 infection. Spike protein and/or its receptor binding domain Davide C, Katja F, Martina B, et al.
CN 113004395 A 20210622 Production of monoclonal antibody against SARS-CoV-2 and application thereof in immunoassay of SARS CoV-2. NP protein Li Z, Xingsu G, Binyang Z, et al.
CN 112940110 A 20210611 Production of anti-SARS-CoV-2 N protein monoclonal antibodies for diagnosis and treatment of COVID-19. N protein Yaoqing C, Bing H, Shuning L, et al.
CN 112794899 A 20210514 Human anti-SARS-CoV-2 neutralizing monoclonal antibodies for diagnosis, prevention, and treatment of COVID-19. Viral receptor binding domain (RBD) Lei C, Tengsen G, Min D, et al.
CN 112724248 A 20210430 Humanized anti-SARS-CoV-2 spike protein nanobodies for diagnosis, prevention, and treatment of COVID-19. Receptor binding domain Xilin W, Zhiwei W.
CN 112661841 A 20210416 Anti-SARS-CoV-2 S2 protein human monoclonal antibody 17-2 for combination therapy with S1-RBD/S1-NTD epitope-neutralizing antibody and for prevention and treatment of COVID-19. Epitope S1-RBD and S1-NTD Lei Y, Yingfen W, Wenjing G, et al.
CN 112625136 A 20210409 Bi-specific antibody having neutralizing activity against two epitopes of SARS-CoV-2 spike protein for diagnosis, prevention, and treatment of COVID-19. Two epitopes of SARS-CoV-2 spike protein Guojun L, Chanjuan L, Junbin S, et al.
CN 112574300 A 20210330 Human anti-SARS-CoV-2 S protein monoclonal antibody for diagnosis, prevention, and treatment of SAR-COV-2 infection. Spike protein Xiaochun W, and Junxin L.
CN 112521496 A 20210319 Anti-SARS-CoV-2 spike protein RBD domain monoclonal antibodies for diagnosis and treatment of COVID-19. Spike protein RBD domain Ke D, Zhaowei G, Xi W, et al.
CN 112409488 A 20210226 Preparation of monoclonal anti-human ACE2 antibody for ACE2 detection, prevention, or treatment of various coronavirus-related disease. Human ACE2 Chunhe W, Yuning C, Yili C, et al.
CN 112225806 A 20210115 Preparation of human antibodies specific to SARS-CoV-2 spike RBD protein for diagnosis and therapy of SARS-CoV-2 infection, SARS, COVID-19 or related disease. Spike RBD protein Yafeng L.
CN 112210004 A 20210112 Preparation of monoclonal anti-SARS-CoV-2 spike protein antibodies for diagnosis and treatment of COVID-19. Spike protein Yang W, Xuefeng N, Chunlin W, et al.
CN 112175073 A 20210105 Preparation of broad spectrum neutralizing anti-SARS-CoV-2 spike protein antibodies for diagnosis, prevention, and treatment of COVID-19. Spike protein Jinghe H, Fan W, Mei L, et al.
CN 112175071 A 20210105 Preparation of novel anti-SARS-CoV-2 spike protein monoclonal antibodies for treatment of COVID-19. Spike protein Jingui Y, Lei Z, Lianjun M, et al.
CN 112159469 A 20210101 anti-SARS-CoV-2 S1-RBD antibodies derived from in vitro monoclonal B cells and high throughput screening for treatment and/or prevention of COVID-19. Spike S1-RBD Jinghe H, Fan W, Mei L, et al.

Note: SARS CoV-2—severe acute respiratory syndrome coronavirus-2; RBD—Receptor binding domain; S, N, proteins—Spike, Nucleocapsid, proteins; ACE2—Angiotensin converting enzyme-2.

This entry is adapted from the peer-reviewed paper 10.3390/ijms222111953


  1. Sanders, J.; Monogue, M.; Jodlowski, T.; Cutrell, J. Pharmacologic Treatments for Coronavirus Disease 2019 (COVID-19). JAMA 2020, 18, 1824–1837.
  2. Torales, J.; O’Higgins, M.; Castaldelli-Maia, J.; Ventriglio, A. The outbreak of COVID-19 coronavirus and its impact on global mental health. Int. J. Soc. Psychiatry 2020, 66, 317–320.
  3. Alharbi, M.M.; Rabbani, S.I.; Asdaq, S.M.B.; Alamri, A.S.; Alsanie, W.F. Infection Spread, Recovery, and Fatality from Coronavirus in Different Provinces of Saudi Arabia. Healthcare 2021, 9, 931.
  4. Liu, B.; Forman, M.; Valsamakis, A. Optimization and evaluation of a novel real-time RT-PCR test for detection of parechovirus in cerebrospinal fluid. J. Virol. Meth. 2019, 272, 1136–1190.
  5. Zhou, P. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature 2020, 579, 270–273.
  6. Reguera, J. Structural bases of coronavirus attachment to host aminopeptidase N and its inhibition by neutralizing antibodies. PLoS Pathog. 2012, 8, e1002859.
  7. Chan, C.E.; Chan, A.H.; Lim, A.P.; Hanson, B.J. Comparison of the efficiency of antibody selection from semi-synthetic scFv and non-immune Fab phage display libraries against protein targets for rapid development of diagnostic immunoassays. J. Immunol. Method. 2011, 373, 79–88.
  8. Ecker, D.M.; Jones, S.D.; Levine, H.L. The therapeutic monoclonal antibody market. mAbs 2015, 7, 9–14.
  9. Hansel, T.T.; Kropshofer, H.; Singer, T.; Mitchell, J.A.; George, A.J. The safety and side effects of monoclonal antibodies. Nat. Rev. Drug Dis. 2010, 9, 325–329.
  10. Torrente-López, A.; Hermosilla, J.; Navas, N.; Cuadros-Rodríguez, L.; Cabeza, J.; Salmerón-García, A. The Relevance of Monoclonal Antibodies in the Treatment of COVID-19. Vaccines 2021, 9, 557.
  11. Jomah, S.; Asdaq, S.M.B.; Alyamani, M.J. Clinical efficacy of antivirals against novel coronavirus (COVID-19): A review. J. Infect. Public Health 2020, 13, 1187–1195.
  12. Asdaq, S.M.B.; Rabbani, S.I.; Imran, M.; Alanazi, A.A.; Alnusir, G.Y.; Al-Shammari, A.A.; Alsubaie, F.H.; Alsalman, A.J. A Review on Potential Antimutagenic Plants of Saudi Arabia. Appl. Sci. 2021, 11, 8494.
  13. Flego, M.; Ascione, A.; Cianfriglia, M.; Vella, S. Clinical development of monoclonal antibody-based drugsin HIV and HCV diseases. BMC Med. 2013, 11, 4–9.
  14. Baskar, S.; Suschak, J.M.; Samija, I.; Srinivasan, R.; Childs, R.W.; Pavletic, S.Z. A human monoclonal antibody drug and target discovery platform for B-cell chronic lymphocytic leukemia based on allogeneic hematopoietic stem cell transplantation and phage display. Blood 2009, 114, 4494–4502.
  15. Glassy, M.C.; Gupta, R. Technical and ethical limitations in making human monoclonal antibodies (an overview). Methods Mol. Biol. 2014, 1060, 9–16.
  16. Mahase, E. COVID-19: FDA authorises neutralising antibody bamlanivimab for non-admitted patients. BMJ 2020, 371, m4362.
  17. Reichert, J.M.; Dewitz, M.C. Anti-infective monoclonal antibodies: Perils and promise of development. Nat. Rev. Drug Discov. 2009, 5, 191–195.
  18. Burmester, G.R.; Panaccione, R.; Gordon, K.B.; McIlraith, M.J.; Lacerda, A.P. Adalimumab: Long-term safety in 23 458 patients from global clinical trials in rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis and Crohn’s disease. Ann. Rheum. Dis. 2013, 72, 517–524.
  19. Tepper, S.; Ashina, M.; Reuter, U.; Brandes, J.L.; Dolezil, D.; Silberstein, S. Safety and efficacy of erenumab for preventive treatment of chronic migraine: A randomised, double-blind, placebo-controlled phase 2 trial. Lancet Neurol. 2017, 16, 425–434.
  20. Dimitrov, D.S.; Marks, J.D. Therapeutic antibodies: Current state and future trends--is a paradigm change coming soon? Methods Mol. Biol. 2009, 525, 1–27.
  21. Lim, C.C.; Woo, P.C.Y.; Lim, T.S. Development of a Phage Display Panning Strategy Utilizing Crude Antigens: Isolation of MERS-CoV Nucleoprotein human antibodies. Sci. Rep. 2019, 9, 6088.
  22. Foster, R.H.; Wiseman, L.R. Abciximab. An updated review of its use in ischaemic heart disease. Drugs 1998, 56, 629–665.
  23. Tsurushita, N.; Hinton, P.R.; Kumar, S. Design of humanized antibodies: From anti-Tac to Zenapax. Methods 2005, 36, 69–83.
  24. Hoffman, W.; Lakkis, F.G.; Chalasani, G. B Cells, Antibodies, and More. Clin. J. Am. Soc. Nephrol. 2016, 11, 137–154.
  25. Norms and Standards of WIPO (World Intellectual Property Organization. 2021. Available online: (accessed on 22 October 2021).
  26. Liu, C.; Zhou, Q.; Li, Y.; Garner, L.V.; Watkins, S.P.; Carter, L.J.; Smoot, J.; Gregg, A.C. Research and Development on Therapeutic Agents and Vaccines for COVID-19 and Related Human Coronavirus Diseases. ACS Cent. Sci. 2020, 6, 315−331.
  27. Monoclonal Antibodies Patent Applications against COVID-19 Filed in World Property Intellectual Organization. 2021. Available online: (accessed on 18 July 2021).
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