Mini-review: The market growth of diagnostic and therapeutic monoclonal antibodies; SARS CoV-2 an example

BACKGROUND: The emergence of novel viruses poses severe challenges to global public health highlighting the crucial necessity for new antivirals. MAIN BODY: Monoclonal antibodies (mAbs) are immunoglobulins that bind with a single epitope. Mouse mAbs are generated by classic hybridoma technology and are mainly used for immunodiagnostics. For immunotherapy, it is critical to use monoclonal antibodies in the human form to minimize adverse reactions. They have been successfully used to treat numerous illnesses, accordingly, an increasing number of mAbs, with high potency against emerging viruses is the target of every biopharmaceutical company. The diagnostic and therapeutic mAbs market grows rapidly into a multi-billion-dollar business. Biopharmaceuticals are innovative resolutions which revolutionized the treatment of significant chronic diseases and malignancies. Currently, a variety of therapeutic options that include antiviral medications, monoclonal antibodies, and immunomodulatory agents are available in the management of COVID-19. SHORT CONCLUSION: The invasion of mAbs in new medical sectors will increase the market magnitude as it is expected to generate revenue of about 300 billion $ by 2025. In the current mini-review, the applications of monoclonal antibodies in immune-diagnosis and immunotherapy will be demonstrated, particularly for COVID-19 infection and will focus mainly on monoclonal antibodies in the market.

Hybridoma technology; advancements, clinical significance, and future aspects

Background Hybridoma technology is one of the most common methods used to produce monoclonal antibodies. In this process, antibody-producing B lymphocytes are isolated from mice after immunizing the mice with specific antigen and are fused with immortal myeloma cell lines to form hybrid cells, called hybridoma cell lines. These hybridoma cells are cultured in a lab to produce monoclonal antibodies, against a specific antigen. This can be achieved by an in vivo or an in vitro method. It is preferred above all the available methods to produce monoclonal antibodies because antibodies thus produced are of high purity and are highly sensitive and specific. Main body of the abstract Monoclonal antibodies are useful in diagnostic, imaging, and therapeutic purposes and have a very high clinical significance. Once hybridoma cells become stable, these cell lines offer limitless production of homogenized antibodies. This method is also cost-effective. The antibodies produced by this method are highly sensitive and specific to the targeted antigen. It is an important tool used in various fields of research such as in toxicology, animal biotechnology, medicine, pharmacology, cell, and molecular biology. Monoclonal antibodies are used extensively in the diagnosis and therapeutic applications. Radiolabeled monoclonal antibodies are used as probes to detect tumor antigens in the living system; also radioisotope coupled antibodies are used for therapeutic target specific action on oncogenic cells. Short conclusion Presently, the monoclonal antibodies used are either raised in mice or rats; this poses a risk of disease transfer from mice to humans. There is no guarantee that antibodies thus created are entirely virus-free, despite the purification process. Also, there are some immunogenic responses observed against the antibodies of mice origin. Technologically advanced techniques such as genetic engineering helped in reducing some of these limitations. Advanced methods are under development to make lab-produced monoclonal antibodies as human as possible. This review discusses the advantages and challenges associated with monoclonal antibody production, also enlightens the advancement, clinical significance, and future aspects of this technique.

Antibody Therapy: Past, Present and Future

The emergence of pandemics like SARS-CoV-2 and a gradual increase in Multidrug Resistant (MDR) infections highlights the need of innovation in therapeutics. Antibodies are one of the potential solutions for long. Antibody therapy has come very long way from the fight against infectious diseases, bacterial toxins to hybridoma technology and monoclonal antibodies. Hybridoma cells receive a deserving attention due to their antigen-specificity. But, as they were murine in origin, Human Anti Murine Antibody (HAMA) emerged. To achieve this, phage display was introduced. The emergence of molecular cloning lead to the generation of genetically engineered recombinant antibodies such as Fab, Fc, Variable Fragment (Fv), Single Chain Variable Fragments (scFv), single domain antibodies, diabodies; like scFv fragments to different moieties, such as drugs toxins, radionuclides, liposomes or quantum dots etc. Minimized antibodies have several advantages like rapid blood clearance, reduced immunogenicity, low retention time in non-target tissues, access to cryptic epitopes facilitating tumor penetration, rapid growth facilitating higher yield and lower production cost. This paper gives an overview of the history of development of antibodies and its fragments as potential therapeutic agents for the treatment of infectious diseases, one of the biggest challenges of humanity.

Monoclonal Antibody Therapy against Acinetobacter baumannii

Background: Extremely drug-resistant (XDR) Acinetobacter baumannii is a notorious and frequently encountered pathogen demanding novel therapeutic interventions. An initial monoclonal antibody (MAb), C8, raised against A. baumannii capsule proved a highly effective treatment against a minority of clinical isolates. To overcome this limitation, we broadened coverage by developing a second antibody for use in a combination regimen. Methods: We sought to develop an additional anti- A. baumannii MAb through hybridoma technology by immunizing mice with sublethal inocula of virulent, XDR clinical isolates not bound by MAb C8. Results: We identified a new antibacterial MAb, 65, which bound to strains in a pattern distinct from and complementary to MAb C8. MAb 65 enhanced macrophage opsonophagocytosis of targeted strains and markedly improved survival in lethal bacteremic sepsis and aspiration pneumonia murine models of A. baumannii infection. MAb 65 was also synergistic with colistin, substantially enhancing protection compared to monotherapy. Treatment with MAb 65 significantly reduced blood bacterial density, ameliorated cytokine production (IL-1β, IL-6, IL-10, and TNF), and sepsis biomarkers. Conclusions: We describe a novel MAb targeting A. baumannii that broadens immunotherapeutic strain coverage, is highly potent and effective, and synergistically improves outcomes in combination with antibiotics.

Second Generation Antibodies Neutralize Emerging SARS-CoV-2 Variants of Concern

Recently emerged SARS-CoV-2 variants show resistance to some antibodies that were authorized for emergency use. We employed hybridoma technology combined with authentic virus assays to develop second generation antibodies, which were specifically selected for their ability to neutralize new variants of SARS-CoV-2. AX290 and AX677, two monoclonal antibodies with non-overlapping epitopes, exhibit subnanomolar or nanomolar affinities to the receptor binding domain of the viral Spike protein carrying amino acid substitutions N501Y, N439K, E484K, K417N, and a combination N501Y/E484K/K417N found in the circulating virus variants. The antibodies showed excellent neutralization of an authentic SARS-CoV-2 virus representing strains circulating in Europe in spring 2020 and also the variants of concern B.1.1.7 and B.1.351. Finally, the combination of the two antibodies prevented the appearance of escape mutations of the authentic SARS-CoV-2 virus. The neutralizing properties were fully reproduced in chimeric mouse-human versions, which may represent a promising tool for COVID-19 therapy.

Introduction on Monoclonal Antibodies

Monoclonal antibodies (mAbs) are a group of antibodies produced by identical clones of B lymphocytes against a particular antigen. mAbs are identical in several properties such as protein sequence, antigen-binding site region, binding affinity for their targets, and identical downstream functional effects. These characteristics of mAbs highlight their differences with the polyclonal antibodies which have heterogenous activities and recognize different epitopes on an antigen. Murine mAbs was the first generation of mAbs developed by hybridoma technology however, because of their murine origin, they can trigger the anti-mouse antibody response in the host which could accelerate mAb clearance and undesirable allergic reactions upon repeated administration. This issue was resolved by developing engineering methods toward producing less immunologic chimeric or humanized antibodies. mAbs applications have become a novel way of targeting antigens in a wide variety of diseases such as autoimmunity, malignancies, and asthma. In addition, high specificity and high affinity binding properties of mAbs make them effective biological reagents in immunodiagnostic assays. They can be used in diagnosis of infectious diseases and detection of certain antigens or in serological assessments for detection of antibodies against a certain antigen. This chapter summarizes the general properties of mAbs, their production processes, and their important diagnostic and therapeutic applications.

Therapeutic Applications of Monoclonal Antibodies in Urologic-Oncology Management - An Update

The idea of utilizing immunotherapy for the treatment of cancers has been appealing to scientists and clinicians for over a several decades. Immunotherapy for cancers encompasses knowledge gained from a wide range of disciplines and has the potential to procure the ‘magic bullet’ for the treatment of cancer. Monoclonal antibody-based treatment of cancer has been recognized as one of the most successful therapeutic strategies for both hematologic malignancies and solid tumours in the last 20 years. The discovery of hybridoma technology in late 1975 and the development of chimeric, humanized, and human antibodies have increased the availability and utility of immunotherapy for the treatment of cancer. Metastatic or recurrent cancer continues to be the bane of the urological oncologist. Despite recent improvements in therapeutic management and outcomes for clinically localized disease overall survival rate in patients with the majority of metastatic and recurrent genitourinary malignancies remains relatively unchanged. By targeting tumours through specific or associated antigens, it is possible to selectively eliminate tumour cells and maintain an acceptable toxicity profile. Therapeutic antibodies that target immune cells are also being developed with the goal of breaking local tolerance and stimulating the patient’s anti-tumor immune response. As with other treatment modalities, immunotherapy is far from perfect and requires additional study to optimize clinical response and overcome therapeutic resistance. Modern advances in the field of immunotherapy hold the promise of providing the clinical urologist/oncologist with new tools to fight urological cancer. However, the literature on monoclonal antibody-based immunotherapy with a particular emphasis on target antigens, monoclonal antibody design and potential applications in the field of urology is limited. Hence, the present chapter focuses on the applications of Immunotherapy using monoclonal antibodies for urologic oncology settings such as prostate, bladder, renal, testicular and penile with a hope to highlight its clinical efficacy and also its mechanisms of action in each of these cancer types.

Application of Microfluidic Technology in Field of Antibody Preparation

Microfluidic technology is a science and technology that can accurately manipulate fluids in micro-sized channels. In recent years, microfluidic devices have attracted wide attention due to its easy manipulation, miniaturized size, high throughput and precise control, which provide a potential platform for antibody screening. This review paper provides an overview of recent advances in microfluidic methods application in the field of antibody preparation. While hybridoma technology and four antibody engineering techniques including phage display, single B cell antibody screening, antibody expression and cell-free protein synthesis are mainly introduced, important advances of experimental models and results are also discussed. Furthermore, the authors expound on the limitations of current microfluidic screening system and present future directions of antibody screening platform based on microfluidics. Antibody preparation on microfluidics combined with other technologies has huge application potential in the field of biomedicine, and it is anticipated to be further developed.