Antibody Engineering Research Articles

The Icarian flight of antibody-drug conjugates: target selection amidst complexity and tackling adverse impacts.

Antibody-drug conjugates (ADCs) represent a promising class of targeted cancer therapeutics that combine the specificity of monoclonal antibodies with the potency of cytotoxic payloads. Despite their therapeutic potential, the use of ADCs faces significant challenges, including off/on-target toxicity and resistance development. This review examines the current landscape of ADC development, focusing on the critical aspects of target selection and antibody engineering. We discuss strategies to increase ADC efficacy and safety, including multitarget approaches, pH-dependent antibodies, and masked peptide technologies. The importance of comprehensive antigen expression profiling in both tumor and normal tissues is emphasized, highlighting the role of advanced technologies, such as single-cell sequencing and artificial intelligence (AI), in optimizing target selection. Furthermore, we explore combination therapies and innovations in linker‒payload chemistry, which may provide approaches for expanding the therapeutic window of ADCs. These advances pave the way for the development of more precise and effective cancer treatments, potentially extending ADC applications beyond oncology.

A humanized anti-MSLN×4-1BB bispecific antibody exhibits potent antitumour activity through 4-1BB signaling activation and fc function without systemic toxicity

BackgroundAgonistic monoclonal antibodies targeting 4-1BB/CD137 have shown preclinical promise, but their clinical development has been limited by severe liver toxicity or limited efficacy. Therefore, a safe and efficient immunostimulatory molecule is urgently needed for cancer immunotherapy.MethodsA novel anti-MSLN×4-1BB bispecific antibody (bsAb) was generated via antibody engineering, and its affinity and activity were detected via enzyme-linked immunosorbent assay (ELISA), flow cytometry, and T-cell activation and luciferase reporter assays. In vivo antitumour activity was assessed by establishing humanized mice bearing human MSLN-expressing MC38 (MC38/hMSLN) or CT26 (CT26/hMSLN) cells, and safety was further evaluated in cynomolgus monkeys.ResultsWe generated two humanized anti-MSLN×4-1BB bsAbs (HK013-G1/G4) by fusing an anti-4-1BB scFv to the C-terminus of an anti-MSLN VHH with an intact Fc fragment from human IgG1 or IgG4. The two bsAbs were able to block the binding of CA125 to MSLN and stimulate 4-1BB signaling pathway, which was strictly dependent on MSLN expression. In particular, HK013-G1 retained Fc function and induced ADCC effect in tumour cells, whereas HK013-G4 did not. Strikingly, HK013-G1 showed superior antitumour activity to HK013-G4 both in vitro and in vivo and remained effective even in the presence of soluble MSLN. HK013-G1 enhanced antitumour immunity and induced durable antigen-specific immune memory to prevent rechallenged tumour growth, even at a dose as low as 1 mg/kg. Furthermore, HK013-G1 did not induce nonspecific production of proinflammatory cytokines and showed good tolerability up to the highest tested dose (30 mg/kg weekly) for 5 weeks, with no HK013-G1-related adverse effects observed in cynomolgus monkeys. In addition, the mean half-life of HK013-G1 was approximately 61 and 97 h at single doses of 3 and 30 mg/kg, respectively.ConclusionThe optimal anti-MSLN×4-1BB bsAb HK013-G1 exhibited synergistic antitumour effects by inducing an ADCC effect (innate immunity) and stimulating the 4-1BB signaling pathway (adaptive immunity) upon cross-bridging with MSLN with no systemic toxicity, which may offer the promise of an improved therapeutic window relative to that of 4-1BB agonists.

Preparation and application of porcine broadly neutralizing monoclonal antibodies in an immunoassay for efficiently detecting neutralizing antibodies against foot-and-mouth disease virus serotype O.

Neutralizing antibodies provide vital protection against foot-and-mouth disease virus (FMDV). The virus neutralization test (VNT) is a gold standard method for the detection of neutralizing antibodies. However, its application is limited due to the requirement for live virus and unsuitability for large-scale serological surveillance. In this study, a porcine broadly neutralizing monoclonal antibody (PO18-10) against FMDV was obtained from the heterologous sequentially vaccinated pig using single-B-cell antibody technology. A competitive enzyme-linked immunosorbent assay (C-ELISA) for detecting neutralizing antibodies against FMDV serotype O was developed using biotinylated PO18-10 as a detector antibody. The sensitivity and specificity of the assay were 100% and 99.55%, respectively, and the positive/negative coincidence rate with VNT was 94%, suggesting that C-ELISA based on natural host-derived monoclonal antibody (mAb) could be a promising tool to detect neutralizing antibodies against FMDV serotype O and evaluate the vaccine efficacy.IMPORTANCEFoot-and-mouth disease virus (FMDV) serotype O is one of the most prevalent serotypes in the world. The neutralizing antibody titers in primo-vaccinated animals are directly related to their level of protection against a virus challenge. The development of a safe, rapid, and accurate method for the detection of the neutralizing antibody is essential for the control and eradication of FMD. In this study, an inter-serotype broadly neutralizing monoclonal antibody PO18-10 was successfully produced using single-B-cell antibody technology from sequentially vaccinated pigs. A competitive ELISA based on this natural host-derived mAb for the detection of neutralizing antibodies against FMDV serotype O was developed and validated. The assay demonstrates high sensitivity, specificity, and coincidence rate with VNT, making it an alternative tool for confirming FMDV infection and evaluating the vaccine efficacy.

Amino Acids Frequency and Interaction Trends: Comprehensive Analysis of Experimentally Validated Viral Antigen-Antibody Complexes.

Antibodies have specific binding capabilities and therapeutic potential for treating various diseases, including viral infections. The amino acid composition of the hypervariable complementarity determining regions (CDR) loops and the framework regions (FR) are the determining factors for the affinity and therapeutic efficacy of the antibodies. In this study selected and curated, 77 viral antigen-human antibody complexes from Protein data bank from the Thera-SAbdab database were analyzed. The results revealed diversity indices within specific CDR regions, amino acid frequencies, paratope-epitope interactions, bond formations, and bond types among the analyzed viral Ag-Ab complexes. The finding revealed that Ser, Gly, Tyr, Thr, and Phe are prominently present in the antibody CDRs. Analysis of CDR profiles indicated an average amino acid diversity of 60-80% in heavy chain CDRs and 45-60% in light chain CDRs. Aromatic residues, particularly Tyr, Phe, and Trp showed significant involvement in the paratope-epitope interactions in the heavy chain, while Tyr, Ser, and Thr were key contributors in the light chain. Furthermore, the study examined the occurrence of amino acids in both light and heavy chains of viral Ag- human Ab complexes, analyzing the presence of amino acids as single residues, dipeptides and tripeptides. The analysis is crucial for enhancing the antibody engineering processes including, design, optimization, affinity enhancement, and overall antibody development.

A non-classical view of antibody properties: Allosteric effect between variable and constant regions.

Historically, antibodies have been divided into two functionally independent domains, the variable (V) region for antigen binding and the constant (C) region for mediating effector functions. However, this classical view of antibody function has been severely challenged by a large and growing number of studies, which reveal long-range conformational interactions and allosteric links between the V and C regions. This review comprehensively summarizes the existing studies on antibody allostery, including allosteric conformational changes induced by covalent modifications or noncovalent ligand binding. In addition, we discuss how intramolecular allosteric signals are transmitted from the V to C regions and vice versa. This review argues that there is sufficient evidence to revisit the structure-function relationship of antibodies. These advances in antibody allostery will provide a blueprint for regulating antibody functions in a simple and highly predictable manner. More focus on antibody allostery will definitely benefit antibody engineering and vaccine design in the field of biotechnology.

Immunoglobulins: Structure, Function, and Therapeutic Applications in Immune Response

The article titled "Immunoglobulins and Its Applications" provides a comprehensive overview of the structure, function, and therapeutic significance of immunoglobulins, also known as antibodies. These vital proteins, produced by plasma cells in response to immunogens, are essential components of the immune system, playing a critical role in recognizing and neutralizing pathogens such as bacteria and viruses. The article elaborates on the five primary classes of immunoglobulins (IgA, IgD, IgE, IgG, and IgM), each distinguished by its unique structural and functional properties. It discusses the molecular composition of immunoglobulins, highlighting the significance of their variable and constant regions in antigen binding. The paper also explores the diverse immune functions mediated by these proteins, including precipitation, agglutination, and neutralization of antigens. Additionally, the article emphasizes the therapeutic applications of immunoglobulins, particularly in treating immune deficiencies and other diseases. Advances in monoclonal antibody technology have significantly expanded the utility of immunoglobulins in both research and medicine, leading to the development of innovative therapeutic approaches such as humanized monoclonal antibodies and bifunctional antibodies. This comprehensive analysis underscores the critical role of immunoglobulins in both natural immunity and therapeutic interventions

Targets and mechanisms of neutralizing monoclonal antibodies against Dengue virus

Dengue fever is a mosquito-borne disease prevalent in tropical and subtropical regions, with its prevalence expanding due to increased global travel. The dengue virus, the causative agent of dengue fever, often co-circulates in the form of four distinct serotypes. Cross-reactive antibodies generated during a primary infection pose a significant risk during secondary infections with different serotypes, and fully protective vaccines and antiviral drugs are yet to be developed. Over the past decade, advances in antibody technology have led to the isolation of numerous monoclonal antibodies against dengue virus, with their neutralizing epitopes elucidated through structure-based analyses. This review highlights the key epitopes associated with neutralizing antibodies against dengue virus and discusses their potential applications in vaccine design and therapeutic antibody development. This review helps systematically summarize the progress in dengue virus neutralizing antibody research, providing a theoretical foundation and technical guidance for the development of novel vaccines and antibody therapeutics.

Antibody Drugs in Alzheimer’s Disease

Alzheimer's disease is one of the important causes of Alzheimer's disease. The prevalence rate has been increasing in recent years, which is a hot issue for the medical community. In view of the pathogenesis of Alzheimer's disease is still not exactly diagnosed, the research and development of related drugs is not particularly ideal. Existing drugs mostly stay in symptomatic treatment. However, in recent years, the medical community has gradually turned to causative treatment. Among them, disease-modifying therapy (DMT) is the most frequently studied drug at present, accounting for 82.5% of the total drugs under consideration. Among the DMT-class drugs, 16 (equivalent to 15.4%) are specifically designed as anti-amyloid beta (Aβ) monoclonal antibodies (Mabs), while 11 (accounting for 10.6%) target tau proteins with monoclonal antibody technology. Through reviewing past literature and comparing data, this paper takes Aducanumab, Lecanemab, and CCTM2 as examples to explore the therapeutic principles and make a summary.

Fc mutagenesis enhances the functionality of anti-RhD monoclonal antibodies.

Haemolytic disease of the foetus and newborn (HDFN) due to Rhesus D (RhD) antigen mismatch between the mother and foetus has been a significant cause of neonatal jaundice, recurrent miscarriage and stillbirth throughout history. Anti-RhD prophylaxis using polyclonal immunoglobulin G (RhD-pIgG) derived from the plasma of RhD-negative donors immunised with RhD-positive red blood cells (RBCs), has reduced the incidence of HDFN, but this approach is currently restricted to developed countries. Monoclonal antibodies (mAbs) offer a promising alternative to address this pressing need, but prior attempts to develop effective anti-RhD mAbs have failed, in some cases due to differences in fucosylation patterns between mAbs produced in cell lines and RhD-pIgG. CHO cell lines, commonly used for pharmaceutical protein production, induce high levels of fucosylation, reducing the antibody-dependent cellular cytotoxicity (ADCC) activity crucial for clearing RhD-positive RBCs. In contrast,RhD-pIgG has lower fucosylation levels, which enhances ADCC activity. Regulating the glycan levels of mAbs during production requires specialized cell lines and culture conditions. In this study, we took an alternative approach through antibody engineering. The Fc regions of two existing anti-RhD mAbs (Brad3 and Fog1) were subjected to mutagenesis to introduce ADCC enhancing mutations and then expressed in CHO cells under standard conditions. We demonstrate that targeted Fc mutagenesis significantly enhanced ADCC compared to the wild-type mAbs, while preserving RhD binding and efficient production in CHO cells. Furthermore, these Fc variants achieved comparable efficacy to RhD-pIgG, suggesting a new strategy for producing anti-RhD mAbs with improved functionality, without the need for glycoengineering.

Benzyl Ammonium Carbamates Undergo Two-Step Linker Cleavage and Improve the Properties of Antibody Conjugates.

Targeted payload delivery strategies, such as antibody-drug conjugates (ADCs), have emerged as important therapeutics. Although considerable efforts have been made in the areas of antibody engineering and labeling methodology, improving the overall physicochemical properties of the linker/payload combination remains an important challenge. Here we report an approach to create an intrinsically hydrophilic linker domain. We find that benzyl α-ammonium carbamates (BACs) undergo tandem 1,6-1,2-elimination to release secondary amines. Using a fluorogenic hemicyanine as a model payload component, we show that a zwitterionic BAC linker improves labeling efficiency and reduces antibody aggregation when compared to a commonly used para-amino benzyl (PAB) linker as well as a cationic BAC. Cellular and in vivo fluorescence imaging studies demonstrate that the model payload is specifically released in antigen-expressing cells and tumors. The therapeutic potential of the BAC linker strategy was assessed using an MMAE payload, a potent microtubule-disrupting agent frequently used for ADC applications. The BAC-MMAE combination enhances labeling efficiency and cellular toxicity when compared to the routinely used PAB-Val-Cit ADC analogue. Broadly, this strategy provides a general approach to mask payload hydrophobicity and improve the properties of targeted agents.

Large scale paired antibody language models.

Antibodies are proteins produced by the immune system that can identify and neutralise a wide variety of antigens with high specificity and affinity, and constitute the most successful class of biotherapeutics. With the advent of next-generation sequencing, billions of antibody sequences have been collected in recent years, though their application in the design of better therapeutics has been constrained by the sheer volume and complexity of the data. To address this challenge, we present IgBert and IgT5, the best performing antibody-specific language models developed to date which can consistently handle both paired and unpaired variable region sequences as input. These models are trained comprehensively using the more than two billion unpaired sequences and two million paired sequences of light and heavy chains present in the Observed Antibody Space dataset. We show that our models outperform existing antibody and protein language models on a diverse range of design and regression tasks relevant to antibody engineering. This advancement marks a significant leap forward in leveraging machine learning, large scale data sets and high-performance computing for enhancing antibody design for therapeutic development.

Comprehensive method for producing high-affinity mouse monoclonal antibodies of various isotypes against (4-hydroxy-3-nitrophenyl)acetyl (NP) hapten.

Monoclonal antibody (mAb) technology has significantly contributed to basic research and clinical settings for various purposes, including protective and therapeutic drugs. However, a rapid and convenient method to generate high-affinity antigen-specific mAbs has not yet been reported. Here, we developed a rapid, easy, and low-cost protocol for antigen-specific mAb production from single memory B cells. Using this method, high-affinity IgG1 mAbs specific to the hapten 4-hydroxy-3-nitrophenylacetyl (NP) were established from NP-CGG immunized C57BL/6 mice within 6 days. Our mAb production system allows flexible switching of IgG1 to any other isotype with the same paratope, enabling the absolute quantification of antigen-specific serum antibody titers and affinity maturation. Additionally, we established a protocol for the production of IgM and IgA, retaining their functional pentamer and dimer structures. This method is also effective against human antigens and pathogens, making it a powerful tool for mAb development in both research and clinical settings.

Investigating the Role of B Cell Receptors in Pathogen Recognition and Immune Response Activation: Implications for Infection Control and Therapeutic Development

B cell receptors (BCRs) are critical components of the adaptive immune system, enabling precise pathogen recognition and the activation of immune responses. This research examines the molecular and genetic mechanisms underlying BCR function, focusing on their role in detecting, binding, and neutralizing infectious agents. By exploring antigen-BCR interactions, we aim to elucidate how BCRs achieve their remarkable specificity and affinity, ultimately shaping the strength and duration of immune responses. Through advanced immunological assays, flow cytometry, and bioinformatics, this study characterizes the diversity of BCR expression across various infectious models. Genetic processes such as somatic hypermutation and clonal selection are analyzed to understand how BCR repertoires adapt to rapidly evolving pathogens. Predictive models developed using machine learning identify biomarkers within BCR pathways, providing insights into acute infections, chronic diseases, and autoimmune conditions. The findings highlight variations in BCR function that influence immune resilience and susceptibility to infections. These insights inform vaccine development, antibody engineering, and therapeutic strategies targeting BCR pathways. This research underscores the potential of BCRs as biomarkers and therapeutic targets, paving the way for innovative approaches in infection control and immune modulation, ultimately advancing precision medicine and adaptive immunity research.

Clonal Variant Analysis of Antibody Engineering Libraries.

In vitro antibody evolution is a powerful technique for improving monoclonal antibodies. This can be achieved by generating artificial diversity on an antibody template, which can be done using different in vitro diversification techniques. The resulting libraries consist of single- or multimutant variants of a defined antibody template that are screened for improved function using antibody display. Here, we describe a bioinformatic protocol for tracking synthetic antibody variants using high-throughput sequencing across screening rounds, enabling efficient high-throughput interpretation of the function of individual mutations in sorted antibody display libraries. The protocol enables a user to achieve precision analysis and interpretation of clonal antibody variant data for discovery purposes, especially for high-throughput antibody engineering or optimization against target antigens.

Beyond Single Clones: High-Throughput Sequencing in Antibody Discovery.

Antibody repertoire sequencing and display library screening are powerful approaches for antibody discovery and engineering that can connect DNA sequence with antibody function. Antibody display and screening studies have made a tremendous impact on immunology and biotechnology over the last decade, accelerated by technological advances in high-throughput DNA sequencing techniques. Indeed, bioinformatic analysis of antibody DNA library data has now taken a central role in modern antibody drug discovery, and is also critical for many ongoing studies of human immune development. Here, we describe current trends in antibody DNA library screening and analysis, and introduce a selection of protocols describing fundamental bioinformatic techniques to enable scientists to efficiently study antibody DNA libraries.

Creation of pH-Sensitive Bioreceptors for Affinity-Type Electrochemical Biosensor Applications

Introduction: Many disease states are characterized by the presence, absence, or change of molecular biological markers, or biomarkers. Common affinity-type recognition elements used in the detection of biomarkers are antibodies, either Immunoglobulins (IgGs) or recombinant fragments. While highly specific, the dissociation kinetics of antibodies highly favors the antibody-antigen complex, resulting in single, endpoint measurements [1]. Endpoint measurements are useful for ex vivo assays, but further antibody engineering is required for in vivo continuous monitoring. A key burden to overcome for using antibodies in continuous monitoring applications is the lack of binding site regeneration [2].Thus, we aim to create pH-modulable single chain fragment variables (scFvs), in which the KD of the scFv can be controlled to favor dissociation. We posit that through mutagenesis of residues within the complementarity-determining regions (CDRs) to histidine, we are able to modulate antibody binding kinetics through a change in pH [3,4]. There is a basis in the literature that supports this antibody design approach [5]. Those working with therapeutic antibodies currently employ similar techniques to effectively “recycle,” or regenerate the binding site of the antibody in vivo [6]. We seek to expand these techniques into the biosensing space to develop continuous, antibody-based biosensors. Methods: ClusPro was utilized to predict the antigen-binding residues in the CDRs of an anti-insulin scFv. From the predicted residues, we selected three amino acid residues to mutate to histidine with the intent of generating pH-modulable mutants. Three single mutants and a triple mutant containing all mutations were designed. The wild-type (WT) scFv, as well as the four mutants were all expressed as a soluble protein using Escherichia coli (E. coli) as a host microorganism. The binding ability of the WT and four mutants was assessed via two assays in differing pH with Bio-Layer Interferometry (BLI). The BLI assay workflow is as follows: biotinylated insulin was immobilized to Octet Streptavidin tips in buffers of either pH 7.4 or 6.0. Following immobilization, either the WT or mutants were introduced to bind to insulin. The resulting association and dissociation sensorgrams were recorded, and nonlinear fitting of the data was performed in GraphPad Prism 10.0. Results and Discussion: Compared to the WT, the triple histidine mutations in the CDR did not eliminate the scFv’s ability to bind to insulin. For the WT, the apparent KD decreased slightly between pH 7.4 and pH 6.0. This could be attributed to the change in pH affecting the streptavidin-biotin solution, or could be due to an artifact of the assay. Further studies would be needed to discern between the two hypotheses. However, there was a pronounced increase in the apparent KD of the triple mutant in a solution of pH 6.0 compared to pH 7.4. These results indicate the combination of mutations led to an observed pH-dependent binding. Further experimentation is needed with the single mutants to elucidate which residue is responsible for pH dependence, or if it is a combination of the three. Conclusions: We employed a rational mutation strategy to generate pH-dependent binding of an anti-insulin scFv. Upon a change in solution pH from 7.4 to 6.0, the triple mutant’s binding equilibrium is shifted, leading to an increase in KD. Further studies are needed to understand the reversibility of this interaction as well as to elucidate what specific residue interactions are contributing to this change.

A Brief Chronicle of Antibody Research and Technological Advances.

This review briefly traces the historical development of antibody research and related technologies. The path from early perceptions of immunity to the emergence of modern immunotherapy has been marked by pivotal discoveries and technological advances. Early insights into immunity led to the development of vaccination and serotherapy. The elucidation of antibody structure and function paved the way for monoclonal antibody technology and its application in diagnosis and therapy. Breakthroughs in genetic engineering have enabled the production of humanized antibodies and the advances in Fc engineering, thereby increasing therapeutic efficacy. The discovery of immune checkpoints and cytokines revolutionized the treatment of cancer and autoimmune diseases. The field continues to evolve rapidly with the advent of antibody-drug conjugates, bispecific antibodies, and CAR T-cell therapies. As we face global health challenges, antibody research remains at the forefront of medical innovation and offers promising solutions for the future.

Unlocking Intracellular Oncology Targets: The Unique Role of Antibody-Based T-Cell Receptor Mimic (TCRm) Therapeutics in T-Cell Engagers (TCEs) and Antibody-Drug Conjugates (ADCs).

Effectively targeting intracellular tumor-associated proteins presents a formidable challenge in oncology, as they are traditionally considered inaccessible to conventional antibody-based therapies and CAR-T cell therapies. However, recent advancements in antibody engineering have revolutionized this field, offering promising new strategies to combat cancer. This review focuses on the innovative use of T-cell receptor mimic (TCRm) antibodies within the therapeutic frameworks of T-cell engagers (TCE) and antibody-drug conjugates (ADCs). TCRm antibodies, designed to recognize peptide-MHC complexes rather than cell surface proteins, integrate the capacity of T-cells to reach intracellular targets with the unique strengths of antibodies. When incorporated into T-cell engaging therapeutics, TCRms redirect T cells to cancer cells, facilitating direct cytotoxicity. In ADCs, TCRm antibodies deliver cytotoxic agents with highly specific targeting to cancer cells, sparing healthy tissues. Together, these antibody-based strategies represent a significant leap forward in oncology, opening new avenues for the treatment of cancers previously deemed untreatable, with other potential applications in autoimmune diseases. This review discusses the mechanisms, clinical advancements, and future prospects of these cutting-edge therapies, highlighting their potential to transform the landscape of cancer treatment.

Using phage display for rational engineering of a higher affinity humanized 3' phosphohistidine-specific antibody.

Histidine phosphorylation (pHis) is a non-canonical post-translational modification (PTM) that is historically understudied due to a lack of robust reagents that are required for its investigation, such as high affinity pHis-specific antibodies. Engineering pHis-specific antibodies is very challenging due to the labile nature of the phosphoramidate (P-N) bond and the stringent requirements for selective recognition of the two isoforms, 1-phosphohistidine (1-pHis) and 3-phosphohistidine (3-pHis). Here, we present a strategy for in vitro engineering of antibodies for detection of native 3-pHis targets. Specifically, we humanized the rabbit SC44-8 anti-3-pTza (a stable 3-pHis mimetic) mAb into a scaffold (herein referred to as hSC44) that was suitable for phage display. We then constructed six unique Fab phage-displayed libraries using the hSC44 scaffold and selected high affinity 3-pHis binders. Our selection strategy was carefully designed to enrich antibodies that bound 3-pHis with high affinity and had specificity for 3-pHis versus 3-pTza. hSC44.20N32FL, the best engineered antibody, has an ~10-fold higher affinity for 3-pHis than the parental hSC44. Eleven new Fab structures, including the first reported antibody-pHis peptide structures were solved by X-ray crystallography. Structural and quantum mechanical calculations provided molecular insights into 3-pHis and 3-pTza discrimination by different hSC44 variants and their affinity increase obtained through in vitro engineering. Furthermore, we demonstrate the utility of these newly developed high-affinity 3-pHis-specific antibodies for recognition of pHis proteins in mammalian cells by immunoblotting and immunofluorescence staining. Overall, our work describes a general method for engineering PTM-specific antibodies and provides a set of novel antibodies for further investigations of the role of 3-pHis in cell biology.

Fc-FcγR interactions during infections: From neutralizing antibodies to antibody-dependent enhancement.

Advances in antibody technologies have resulted in the development of potent antibody-based therapeutics with proven clinical efficacy against infectious diseases. Several monoclonal antibodies (mAbs), mainly against viruses such as SARS-CoV-2, HIV-1, Ebola virus, influenza virus, and hepatitis B virus, are currently undergoing clinical testing or are already in use. Although these mAbs exhibit potent neutralizing activity that effectively blocks host cell infection, their antiviral activity results not only from Fab-mediated virus neutralization, but also from the protective effector functions mediated through the interaction of their Fc domains with Fcγ receptors (FcγRs) on effector leukocytes. Fc-FcγR interactions confer pleiotropic protective activities, including the clearance of opsonized virions and infected cells, as well as the induction of antiviral T-cell responses. However, excessive or inappropriate activation of specific FcγR pathways can lead to disease enhancement and exacerbated pathology, as seen in the context of dengue virus infections. A comprehensive understanding of the diversity of Fc effector functions during infection has guided the development of engineered antiviral antibodies optimized for maximal effector activity, as well as the design of targeted therapeutic approaches to prevent antibody-dependent enhancement of disease.