Antibodies

15 pages, 2241 KiB

Open AccessArticle

Potentiating Antibody-Dependent Cellular Cytotoxicity in Triple-Negative Breast Cancer via the Humanized Anti-CD147 Antibody

by Kanyarat Thongheang, Thanathat Pamonsupornwichit, Kanokporn Sornsuwan, On-anong Juntit, Tawan Chokepaichitkool, Weeraya Thongkum, Umpa Yasamut and Chatchai Tayapiwatana

Antibodies 2025, 14(2), 36; https://doi.org/10.3390/antib14020036 - 11 Apr 2025

Abstract

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype with high metastatic potential, poor prognosis, and the absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). The lack of these receptors limits the standard treatments, such as hormone [...] Read more.

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype with high metastatic potential, poor prognosis, and the absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). The lack of these receptors limits the standard treatments, such as hormone therapies and HER2-targeted antibodies like trastuzumab. These challenges highlight the critical need for novel therapeutic strategies. CD147, a transmembrane glycoprotein overexpressed in TNBC, promotes tumor progression, metastasis, and chemoresistance, making it a promising therapeutic target. This study evaluates the antibody-dependent cellular cytotoxicity (ADCC) of HuM6-1B9, a humanized anti-CD147 antibody, against MDA-MB-231 cells, a TNBC model. Methods: CFSE-labelled MDA-MB-231 cells were co-cultured with PBMCs as effector cells (E:T ratio 80:1) in the presence of HuM6-1B9 and incubated for 4 h. Cells were then collected and stained with PI, and CFSE+/PI+ dead target cells were analyzed by flow cytometry. Results: Co-culturing MDA-MB-231 cells with peripheral blood mononuclear cells (PBMCs) in the presence of HuM6-1B9 demonstrated effective ADCC induction without direct cytotoxicity. HuM6-1B9 induced 54.01% cancer cell death via ADCC, significantly outperforming trastuzumab (26.14%) while sparing PBMCs. Conclusion: These findings support HuM6-1B9 as a prospective TNBC therapeutic and warrant further investigation into its clinical potential. Full article

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25 pages, 3552 KiB

Open AccessReview

A Comprehensive Review About the Use of Monoclonal Antibodies in Cancer Therapy

by Angel Justiz-Vaillant, Bijay Raj Pandit, Chandrashekhar Unakal, Sehlule Vuma and Patrick Eberechi Akpaka

Antibodies 2025, 14(2), 35; https://doi.org/10.3390/antib14020035 - 11 Apr 2025

Abstract

Monoclonal antibodies (mAbs) targeting various pathways in cancer therapy play crucial roles in enhancing the immune system’s ability to recognise and eliminate tumour cells. These therapies are designed to either block inhibitory immune checkpoint pathways or to target specific tumour cell markers for [...] Read more.

Monoclonal antibodies (mAbs) targeting various pathways in cancer therapy play crucial roles in enhancing the immune system’s ability to recognise and eliminate tumour cells. These therapies are designed to either block inhibitory immune checkpoint pathways or to target specific tumour cell markers for direct destruction. Additionally, mAbs can modulate the tumour microenvironment, enhance antibody-dependent cellular cytotoxicity, and inhibit angiogenesis, further amplifying their therapeutic impact. Below is a summary of monoclonal antibodies targeting key pathways, along with their indications and mechanisms of action, which are reviewed based on therapeutic mechanisms. Full article

(This article belongs to the Special Issue Emerging Antibody Engineering Strategies and Applications for Immunotherapy of Cancer)

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7 pages, 6376 KiB

Open AccessCase Report

An Exceedingly Rare Case of Mechanobullous Epidermolysis Bullosa Acquisita in a Prepubertal Child: A Review of the Clinical and Laboratory Considerations

by Aleksandra Wiktoria Bratborska, Maciej Spałek, Monika Bowszyc-Dmochowska and Marian Dmochowski

Antibodies 2025, 14(2), 34; https://doi.org/10.3390/antib14020034 - 11 Apr 2025

Abstract

Introduction: Epidermolysis bullosa acquisita (EBA) is a rare autoimmune disease causing subepithelial blistering due to autoantibodies against type VII collagen. While mechanobullous EBA predominantly affects adults, our report presents an exceedingly rare case in an 11-year-old football player. Case Report: The patient reported [...] Read more.

Introduction: Epidermolysis bullosa acquisita (EBA) is a rare autoimmune disease causing subepithelial blistering due to autoantibodies against type VII collagen. While mechanobullous EBA predominantly affects adults, our report presents an exceedingly rare case in an 11-year-old football player. Case Report: The patient reported a one-year history of blistering and scarring on the knees and scrotum. The diagnosis was established with direct immunofluorescence (DIF), mosaic indirect immunofluorescence (IIF) showing IgG antibodies reacting with the dermal side of salt-split primate skin, and multiplex ELISA revealing an elevated level of IgG antibodies against type VII collagen. Treatment with a superpotent topical glucocorticosteroid and activity modifications improved his condition. Review: This case highlights the importance of considering EBA in differential diagnoses of pediatric blistering diseases and suggests that conservative management may be effective in mild cases. We also review clinical and laboratory considerations on the topic of childhood EBA. Conclusions: Further studies are essential to develop evidence-based guidelines for pediatric EBA. Full article

(This article belongs to the Section Antibody-Based Diagnostics)

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17 pages, 1942 KiB

Open AccessArticle

Effect of Acute Lung Injury (ALI) Induced by Lipopolysaccharide (LPS) on the Pulmonary Pharmacokinetics of an Antibody

by Shweta Jogi and Dhaval K. Shah

Antibodies 2025, 14(2), 33; https://doi.org/10.3390/antib14020033 - 6 Apr 2025

Abstract

Objective: To investigate the effect of Lipopolysaccharide (LPS)-induced acute lung injury (ALI) on the pulmonary pharmacokinetics (PK) of a systemically administered antibody in mice. Method: The PK of a non-target-binding antibody was evaluated in healthy mice and mice with intratracheal instillation of 5 [...] Read more.

Objective: To investigate the effect of Lipopolysaccharide (LPS)-induced acute lung injury (ALI) on the pulmonary pharmacokinetics (PK) of a systemically administered antibody in mice. Method: The PK of a non-target-binding antibody was evaluated in healthy mice and mice with intratracheal instillation of 5 mg/kg LPS. The plasma, bronchoalveolar lavage (BAL), trachea, bronchi, and lung homogenate PK of the antibody were measured following intravenous administration of 5 mg/kg antibody dose. Noncompartmental analysis was performed to determine AUC values. Antibody concentrations in all biological matrices were quantified using qualified ELISA. The effect of ALI on BAL albumin and total protein concentrations was also determined. BAL protein concentrations were corrected for dilution using plasma urea concentrations. Results: Intratracheal instillation of LPS and the resultant ALI led to ~2–4-fold higher concentrations of albumin and proteins in the BAL. LPS-induced ALI also notably altered the pulmonary PK of the antibody. The effect of ALI on the antibody PK was time and tissue dependent. The trachea and bronchi showed ~1.7-fold and ~1.4-fold lower antibody exposure compared with the control group, but the BAL fluid exhibited ~4-fold increase in antibody exposure following LPS treatment. Most noticeable changes in antibody PK occurred 24 h after LPS administration, and the effect was temporary for the bronchi and trachea. However, the changes in lung homogenate and, more notably, in BAL persisted until the end of the experiment. Thus, our investigation suggests that due to the acute nature of ALI-induced pathophysiology and the changing severity of the disease, the dose and timing of antibody administration following ALI may need to be optimized based on the target site of action (e.g., bronchi, trachea, BAL, lung parenchyma, etc.) to maximize the therapeutic effect of the antibody. Conclusions: ALI may significantly affect pulmonary PK of systemically administered antibodies. Changes caused by ALI are time and tissue dependent, and hence, the timing and dose of antibody following ALI may need to be optimized to maximize the therapeutic effect of the antibody at the site of action. Full article

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11 pages, 1239 KiB

Open AccessArticle

A Nationwide Seroprevalence Study for Measles in Individuals of Fertile Age in Romania

by Aurora Stanescu, Simona Maria Ruta, Mihaela Leustean, Ionel Iosif, Camelia Sultana, Anca Maria Panaitescu, Florentina Ligia Furtunescu, Costin Cernescu and Adriana Pistol

Antibodies 2025, 14(2), 32; https://doi.org/10.3390/antib14020032 - 2 Apr 2025

Abstract

Background/Objectives: Romania remains endemic for measles due to suboptimal vaccine coverage rates. During the last three epidemics, the highest incidence of measles was recorded in children younger than 1 year, who should have been partially protected by maternal antibodies. A nationwide cross-sectional seroprevalence [...] Read more.

Background/Objectives: Romania remains endemic for measles due to suboptimal vaccine coverage rates. During the last three epidemics, the highest incidence of measles was recorded in children younger than 1 year, who should have been partially protected by maternal antibodies. A nationwide cross-sectional seroprevalence study was conducted on persons of fertile age, to evaluate potential immunity gaps in the population. Methods: Between June and October 2020, 959 serum samples were collected from individuals aged 25–44 years (46.5% females) from all the geographic regions in Romania. Measles IgG antibodies were assessed using an enzyme-linked immune assay (DIA.PRO-Diagnostic Bioprobes Srl, Italy). Statistical analysis was performed in IBM SPSS Statistics 27.0, using Fisher’s exact and chi-squared tests to test for associations between seropositivity and demographic factors, with p < 0.05 considered statistically significant. Results: The overall measles seroprevalence was 77%, without gender- or geographic region-related differences. Both the seropositivity rate and the measles antibodies titers increased with age, with the highest difference between the oldest and the youngest age group (p = 0.057), suggesting persistent immunity after natural infection in older individuals or anamnestic responses in vaccinated persons, caused by repeated exposures to the circulating virus. An additional confirmatory pilot study on 444 pregnant women confirmed the low level of measles seroprevalence (68.4%), with a significant upward trend in older ages (75% in those aged >40 years old vs. 65% in those aged 25–29 years, p = 0.018 and mean reactivity of measles antibodies 3.05 ± 1.75 in those aged >40 years vs. 2.28 ± 1.39 in those aged 25–29 years, p = 0.037). Conclusions: This study signals critical immunity gaps in the population that contribute to the accumulation of susceptible individuals and recurrent measles outbreaks. The absence of measles antibodies in women of childbearing age increases the newborn’s susceptibility to infection, with potentially severe complications. Full article

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22 pages, 4237 KiB

Open AccessArticle

Impact of Monoclonal Antibody Aggregates on Effector Function Characterization

by Wendy J. Walton, Shousong Jason Zhang, Joseph J. Wilson, Briana N. Harvey, Matthew Clemens and Yingmei Gu

Antibodies 2025, 14(2), 31; https://doi.org/10.3390/antib14020031 - 2 Apr 2025

Abstract

Background/Objectives: Monoclonal antibodies have successfully been used for a variety of indications. Many therapeutic antibodies are IgG1 and elicit effector functions as part of their mechanism of action. It is well known that aggregate levels should be controlled for therapeutic antibodies. Although there [...] Read more.

Background/Objectives: Monoclonal antibodies have successfully been used for a variety of indications. Many therapeutic antibodies are IgG1 and elicit effector functions as part of their mechanism of action. It is well known that aggregate levels should be controlled for therapeutic antibodies. Although there are several reports describing the impact of antibody aggregates on FcγR binding, most of these have been performed with surface plasmon resonance in an avidity-based format. What is less well known is which Fcγ receptor is most impacted by antibody aggregation and how antibody aggregates impact binding to Fcγ receptors in solution-based formats and in cell-based assays. Methods: An effector-competent IgG1 (mAb1) was forcibly degraded and fractionated by size exclusion chromatography to enrich for aggregates. The fractions were examined for FcγR binding by SPR with different formats and in solution. The fractions were also analyzed with cell-based FcγR reporter assays. Results: All Fcγ receptors displayed increased binding to enriched mAb1 aggregates in the avidity-based SPR methods and in solution, with FcγRIIa impacted the most. When examined with an antibody-down SPR format that is not usually susceptible to avidity, FcγRIIa did not show increased binding with mAb1 aggregation. Although activity for mAb1 aggregates increased slightly in an FcγRIIa cell-based reporter assay, it decreased in the FcγRIIIa reporter assay (most likely due to differences in fucosylation from the reference standard). Conclusions: Monoclonal antibody aggregation can impact FcγR binding for avidity-based binding formats. Even at low levels of antibody aggregation, FcγRII binding increases substantially. Full article

(This article belongs to the Section Antibody-Based Therapeutics)

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14 pages, 1893 KiB

Open AccessArticle

T330M Substitution in the Sodium-Dependent Phosphate Transporter NaPi2b Abolishes the Efficacy of Monoclonal Antibodies Against MX35 Epitope

by Leisan F. Bulatova, Vera S. Skripova, Aisylu R. Sagdeeva, Ramilia A. Vlasenkova, Tatiana A. Bugaenko, Rezeda R. Galimova, Alfiya I. Nesterova, Yuliya V. Filina and Ramziya G. Kiyamova

Antibodies 2025, 14(2), 30; https://doi.org/10.3390/antib14020030 - 1 Apr 2025

Abstract

Background: Monoclonal antibodies against the sodium-dependent phosphate transporter NaPi2b (SLC34A2) represent a promising approach in the treatment of ovarian and lung cancer. Of particular interest is the potential cancer-specific MX35 epitope of NaPi2b, as it serves as a target for monoclonal [...] Read more.

Background: Monoclonal antibodies against the sodium-dependent phosphate transporter NaPi2b (SLC34A2) represent a promising approach in the treatment of ovarian and lung cancer. Of particular interest is the potential cancer-specific MX35 epitope of NaPi2b, as it serves as a target for monoclonal antibodies studied at various stages of preclinical and clinical trials. However, variations in the NaPi2b protein structure may limit the efficacy of therapeutic antibodies by affecting the accessibility of the MX35 epitope. Methods: An in silico analysis was performed using data from 101,562 tumor samples. Genomic DNA sequencing was conducted on blood samples from patients with ovarian carcinoma, breast cancer, and renal carcinoma to access the frequency of germline mutations in the SLC34A2 gene region encoding the MX35 epitope. To assess the impact of the selected mutation, we generated a model cell line through site-directed mutagenesis carrying the mutant NaPi2b variant. Results: Using in silico analysis, we identified 17 unique variants in the SLC34A2 gene leading to amino acid substitutions within the MX35 epitope of the NaPi2b. Among these, the most prevalent mutation, c.989C>T, resulting in p.T330M substitution, was detected in 5 out of 64 patients through genomic DNA sequencing. Using site-directed mutagenesis, we created the OVCAR-8/NaPi2b^p.T330M model cell line. L3 (28/1) monoclonal antibodies specific to the MX35 epitope failed to recognize the mutant NaPi2b^p.T330M variant compared to the wild-type of the NaPi2b in both Western blot and confocal microscopy experiments. Conclusions: The obtained data may serve as a basis for predicting the efficacy of monoclonal antibody-based targeted therapy binding to the MX35 epitope of NaPi2b in the treatment of oncological diseases. Full article

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11 pages, 2759 KiB

Open AccessArticle

A Novel Method for Preparing Uniform Micro-Sized Dry Powder Formulations, Including Aggregation-Controlled VHH

by Tatsuru Moritani, Hidekazu Masaki, Ryo Yonehara, Takeru Suzuki, Hidenao Arai, Masayuki Tsuchiya and Naoto Nemoto

Antibodies 2025, 14(2), 29; https://doi.org/10.3390/antib14020029 - 31 Mar 2025

Abstract

Background: The preparation of antibodies in powder form without changing their physicochemical properties may enable their use in new drug delivery system therapies or non-refrigerated storage. The variable domain of heavy-chain antibodies (VHHs) is more suited for this purpose than that of conventional [...] Read more.

Background: The preparation of antibodies in powder form without changing their physicochemical properties may enable their use in new drug delivery system therapies or non-refrigerated storage. The variable domain of heavy-chain antibodies (VHHs) is more suited for this purpose than that of conventional antibodies because of VHHs’ high thermal stability and ability to refold. Methods: In this report, the fine droplet drying (FDD) process was selected as the powderization technique because of its favorable features, such as mild drying conditions and the generation of uniform particle sizes. The aggregation, binding, particle, and in vitro inhalation properties of the prepared VHH powders (VHHps) were evaluated. Results: The amount of aggregated VHHs present in the VHHps depended on the flow temperature during the FDD process, with higher temperatures yielding a higher aggregation ratio. In contrast, no significant difference in binding activity was observed between each VHHp preparation and the native VHHs. However, this process degraded VHHs or inactivated their function, and ultimately, only about 30% of the original VHHs were functional, whereas the remaining VHHs that were not degraded showed little loss of functionality, even after storage at room temperature for more than two years. Analysis of the VHHp samples revealed that the particles were uniformly spherical with a single-micron size. The VHHps showed fine inhalation properties in the inhalation property test. Conclusions: These findings suggest that the FDD process affords various VHH powder formulations, including pharmaceutical formulations. Full article

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15 pages, 3599 KiB

Open AccessArticle

Discovery of Antibodies Against Endemic Coronaviruses with NGS-Based Human Fab Phage Display Platform

by Oscar Chi-Chien Pan, Sean Miller, Ruchin Patel, Shreya Mukhopadhyay, Giancarlo Sarullo, Gwenny Go, Jennifer Galli, Jamie Hessels, Barbara Schlingmann-Molina, Emmanuel Ndashimye, Zhiyun Wen, Christopher Warren, Eberhard Durr, Lan Zhang, Kalpit A. Vora, Arthur Fridman and Zhifeng Chen

Antibodies 2025, 14(2), 28; https://doi.org/10.3390/antib14020028 - 27 Mar 2025

Abstract

Background: There is an unmet medical need to develop a vaccine targeting endemic coronaviruses. Antigen-specific monoclonal antibodies (mAbs) are crucial for many assays to support vaccine development. Objective: In this study, we used the HuCal Fab phage display library with a diversity of [...] Read more.

Background: There is an unmet medical need to develop a vaccine targeting endemic coronaviruses. Antigen-specific monoclonal antibodies (mAbs) are crucial for many assays to support vaccine development. Objective: In this study, we used the HuCal Fab phage display library with a diversity of 4.5 × 10¹⁰ to identify antibodies specific to the spike proteins of the four endemic coronaviruses: OC43, NL63, 229E, and HKU1. Methods: As proof of concept, we established a newly designed platform using a long-read NGS workflow for antibody discovery and compared the results against the traditional workflow using Sanger sequencing consisting of lengthy and laborious benchwork. Results: The long-read NGS workflow identified most of the antibodies seen from the Sanger sequencing workflow, and many more additional antigen-specific antibodies against the endemic coronaviruses. Overall efficiency improved up to three times, comparing the traditional workflow with the NGS workflow. Of the 113 NGS-derived mAbs isolated to bind the four endemic coronavirus spike proteins, 107/113 (94.7%) had potent ELISA binding affinities (EC50 < 150 ng/mL, or <1 nM), and 61/113 (54%) had extremely potent ELISA binding affinities (EC50 of <15 ng/mL, or <0.1 nM). Conclusions: We successfully developed and incorporated the long-read NGS workflow to generate target-specific antibodies with many antibodies at sub-nanomolar affinities that are likely missed by a traditional workflow. We identified strong neutralizing antibodies, proving that our endemic spike proteins are capable of generating antibodies that could offer protection against the endemic HCoVs. Full article

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13 pages, 633 KiB

Open AccessArticle

Low Serological Agreement of Hepatitis E in Immunocompromised Cancer Patients: A Comparative Study of Three Anti-HEV Assays

by Isabel-Elena Haller, Mark Reinwald, Janine Kah, Franz A. M. Eggert, Sandra Schwarzlose-Schwarck, Kristoph Jahnke, Stefan Lüth and Werner Dammermann

Antibodies 2025, 14(2), 27; https://doi.org/10.3390/antib14020027 - 24 Mar 2025

Abstract

Background/Objectives: Hepatitis E virus (HEV) is one of the leading causes of acute hepatitis, with immunosuppressed individuals, such as oncology patients, being particularly vulnerable to chronic infections that may progress to liver disease or fatal outcomes. Assay variability complicates HEV prevalence assessment in [...] Read more.

Background/Objectives: Hepatitis E virus (HEV) is one of the leading causes of acute hepatitis, with immunosuppressed individuals, such as oncology patients, being particularly vulnerable to chronic infections that may progress to liver disease or fatal outcomes. Assay variability complicates HEV prevalence assessment in at-risk groups. This study aimed to compare the reliability and concordance of three HEV antibody assays—Wantai, Euroimmun, and Elecsys^®—in immunosuppressed oncology patients. Methods: In this prospective pilot study, serum samples were obtained from oncology patients between September 2020 and October 2021. Samples were collected both at baseline (treatment-naive) and during ongoing treatment. A healthy control group was retrospectively included for comparative analysis. Anti-HEV IgM and IgG antibodies were tested in all samples using enzyme-linked immunosorbent assays (Wantai, Euroimmun) and an electrochemiluminescence immunoassay (Elecsys^®). Demographic and clinical data, along with information on HEV risk factors, were extracted from medical records and patient questionnaires. Results: HEV IgM prevalence ranged from 0% (Wantai) to 6% (Elecsys^®), while IgG prevalence was 12% (Euroimmun), 38% (Wantai), and 53% (Elecsys^®). Concordance was poor, with Cohen’s Kappa values indicating slight to moderate agreement (κ = 0.000–0.553). Patients with hematological malignancies exhibited the highest IgG seroprevalence. Risk factor analysis revealed the highest association between HEV exposure and the consumption of undercooked pork or crop-based agriculture. Conclusions: Significant variability among HEV serological assays highlights the challenges of reliable HEV diagnostics in immunosuppressed oncology patients. Assay selection and improved testing strategies are critical for this high-risk group. Full article

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19 pages, 277 KiB

Open AccessReview

Future Landscape of Anti-Claudin 18.2 Antibodies in Gastric Adenocarcinoma

by Wendy M. Covert and Jane E. Rogers

Antibodies 2025, 14(1), 26; https://doi.org/10.3390/antib14010026 - 18 Mar 2025

Abstract

Advanced gastric adenocarcinoma (GAC) carries a poor prognosis. Targeted therapy in GAC has traditionally been limited to anti-human epidermal growth factor receptor-2 and anti-vascular endothelial growth factor agents. Recent years have brought immune checkpoint therapy to the GAC treatment landscape. However, continued discovery [...] Read more.

Advanced gastric adenocarcinoma (GAC) carries a poor prognosis. Targeted therapy in GAC has traditionally been limited to anti-human epidermal growth factor receptor-2 and anti-vascular endothelial growth factor agents. Recent years have brought immune checkpoint therapy to the GAC treatment landscape. However, continued discovery of targeted therapy in GAC is needed. Claudins, transmembrane proteins located in tight junctions of epithelial and endothelial cells, help regulate cellular polarity. Claudin dysregulation has been linked to cancers and other diseases. Claudin 18.2 specifically has become a new novel and exciting biomarker for GAC. Many agents are in the investigative pipeline, including monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, and chimeric T-cell therapy. Recently, zolbetuximab, an anti-claudin 18.2 monoclonal antibody, was the first of these agents to get FDA approval. Here, we review zolbetuximab’s place in therapy along with other agents being explored. Full article

10 pages, 876 KiB

Open AccessReview

Is There a Diagnostic and Prognostic Role for Anti-Nephrin Autoantibodies in Diabetic Nephropathy?

by Han Sean Lee, Henry H. L. Wu, Arvind Ponnusamy, Helen Alderson and Rajkumar Chinnadurai

Antibodies 2025, 14(1), 25; https://doi.org/10.3390/antib14010025 - 12 Mar 2025

Abstract

Diabetic nephropathy (DN) is one of the key causes of end-stage kidney disease worldwide, especially in developed countries. The classic pathogenic development of DN is characterized by microalbuminuria which would progress to nephrotic-range proteinuria and loss of kidney function. The degree of albuminuria [...] Read more.

Diabetic nephropathy (DN) is one of the key causes of end-stage kidney disease worldwide, especially in developed countries. The classic pathogenic development of DN is characterized by microalbuminuria which would progress to nephrotic-range proteinuria and loss of kidney function. The degree of albuminuria is considered an independent risk factor for all-cause mortality in patients with DN. It is now well established that albuminuria stems from disruptions in podocyte structure and function. Podocytes play a major role in the glomerular filtration barrier. The nephrin protein has been identified as a core component of the slit diaphragm in podocytes, and as such, the downregulation of nephrin expression has been described well in various proteinuric glomerulopathies, including DN. Previous studies have shown that the presence of urinary nephrin potentially signifies an early marker of podocyte injury in DN. More recently, there have been increasing bodies of evidence which suggest that circulating autoantibodies targeting nephrin contributes to the pathogenesis of podocytopathies. However, the functional significance of these circulating autoantibodies in patients with DN is not well understood. In this review, we aim to evaluate the significance of nephrin dysregulation in the pathogenesis of DN based on the current available literature and provide an overview on the application of circulating anti-nephrin autoantibodies in relation to its diagnostic as well as prognostic role in podocytopathies, including DN. Full article

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16 pages, 704 KiB

Open AccessReview

Anti-ADAMTS13 Autoantibodies in Immune-Mediated Thrombotic Thrombocytopenic Purpura

by Michael R. Snyder and Robert W. Maitta

Antibodies 2025, 14(1), 24; https://doi.org/10.3390/antib14010024 - 10 Mar 2025

Abstract

Autoantibodies to ADAMTS13 are at the center of pathology of the immune-mediated thrombotic thrombocytopenic purpura. These autoantibodies can be either inhibitory (enzymatic function) or non-inhibitory, resulting in protein depletion. Under normal physiologic conditions, antibodies are generated in response to foreign antigens, which can [...] Read more.

Autoantibodies to ADAMTS13 are at the center of pathology of the immune-mediated thrombotic thrombocytopenic purpura. These autoantibodies can be either inhibitory (enzymatic function) or non-inhibitory, resulting in protein depletion. Under normal physiologic conditions, antibodies are generated in response to foreign antigens, which can include infectious agents; however, these antibodies may at times cross-react with self-epitopes. This is one of the possible mechanisms mediating formation of anti-ADAMTS13 autoantibodies. The process known as “antigenic mimicry” may be responsible for the development of these autoantibodies that recognize and bind cryptic epitopes in ADAMTS13, disrupting its enzymatic function over ultra large von Willebrand factor multimers, forming the seeds for platelet activation and microthrombi formation. In particular, specific amino acid sequences in ADAMTS13 may lead to conformational structures recognized by autoantibodies. Generation of these antibodies may occur more frequently among patients with a genetic predisposition. Conformational changes in ADAMTS13 between open and closed states can also constitute the critical change driving either interactions with autoantibodies or their generation. Nowadays, there is a growing understanding of the role that autoantibodies play in ADAMTS13 pathology. This knowledge, especially of functional qualitative differences among antibodies and the ADAMTS13 sequence specificity of such antibodies, may make possible the development of targeted therapeutic agents to treat the disease. This review aims to present what is known of autoantibodies against ADAMTS13 and how their structure and function result in disease. Full article

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16 pages, 2125 KiB

Open AccessArticle

The Use of Heterologous Antigens for Biopanning Enables the Selection of Broadly Neutralizing Nanobodies Against SARS-CoV-2

by Vazirbek S. Aripov, Anna V. Zaykovskaya, Ludmila V. Mechetina, Alexander M. Najakshin, Alexander A. Bondar, Sergey G. Arkhipov, Egor A. Mustaev, Margarita G. Ilyina, Sophia S. Borisevich, Alexander A. Ilyichev, Valentina S. Nesmeyanova, Anastasia A. Isaeva, Ekaterina A. Volosnikova, Dmitry N. Shcherbakov and Natalia V. Volkova

Antibodies 2025, 14(1), 23; https://doi.org/10.3390/antib14010023 - 7 Mar 2025

Abstract

Background: Since the emergence of SARS-CoV-2 in the human population, the virus genome has undergone numerous mutations, enabling it to enhance transmissibility and evade acquired immunity. As a result of these mutations, most monoclonal neutralizing antibodies have lost their efficacy, as they are [...] Read more.

Background: Since the emergence of SARS-CoV-2 in the human population, the virus genome has undergone numerous mutations, enabling it to enhance transmissibility and evade acquired immunity. As a result of these mutations, most monoclonal neutralizing antibodies have lost their efficacy, as they are unable to neutralize new variants. Antibodies that neutralize a broad range of SARS-CoV-2 variants are of significant value in combating both current and potential future variants, making the identification and development of such antibodies an ongoing critical goal. This study discusses the strategy of using heterologous antigens in biopanning rounds. Methods: After four rounds of biopanning, nanobody variants were selected from a phage display library. Immunochemical methods were used to evaluate their specificity to the S protein of various SARS-CoV-2 variants, as well as to determine their competitive ability against ACE2. Viral neutralization activity was analyzed. A three-dimensional model of nanobody interaction with RBD was constructed. Results: Four nanobodies were obtained that specifically bind to the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein and exhibit neutralizing activity against various SARS-CoV-2 strains. Conclusions: The study demonstrates that performing several rounds of biopanning with heterologous antigens allows the selection of nanobodies with a broad reactivity spectrum. However, the fourth round of biopanning does not lead to the identification of nanobodies with improved characteristics. Full article

(This article belongs to the Section Antibody Discovery and Engineering)

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24 pages, 1107 KiB

Open AccessReview

Treatment of Ebola Virus Disease: From Serotherapy to the Use of Monoclonal Antibodies

by Dmitriy N. Shcherbakov, Anastasiya A. Isaeva and Egor A. Mustaev

Antibodies 2025, 14(1), 22; https://doi.org/10.3390/antib14010022 - 5 Mar 2025

Abstract

Ebola virus disease (EVD) is an acute illness with a high-case fatality rate (CFR) caused by an RNA virus belonging to the Filoviridae family. Over the past 50 years, regular EVD outbreaks have been reported. The West African EVD outbreak of 2013–2016 proved [...] Read more.

Ebola virus disease (EVD) is an acute illness with a high-case fatality rate (CFR) caused by an RNA virus belonging to the Filoviridae family. Over the past 50 years, regular EVD outbreaks have been reported. The West African EVD outbreak of 2013–2016 proved to be significantly more widespread and complex than previous ones, resulting in approximately 11,000 deaths. A coordinated international effort was required to bring the outbreak under control. One of the main challenges faced by clinicians and researchers combating EVD was the absence of vaccines and preventive treatments. Only recently have efforts led to the development of effective therapeutic options. Among these, monoclonal antibody-based drugs have emerged as the most promising agents for the urgent treatment of EVD. This article aims to review the key milestones in the development of antibody-based therapies for EVD, tracing the journey from the use of convalescent serum to the creation of effective monoclonal antibody-based drugs and their combinations. Full article

(This article belongs to the Section Antibody-Based Therapeutics)

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14 pages, 2341 KiB

Open AccessCommunication

Development of Fully Human Antibodies Targeting SIRPα and PLA2G7 for Cancer Therapy

by Seungmin Shin, Du-San Baek, John W. Mellors, Dimiter S. Dimitrov and Wei Li

Antibodies 2025, 14(1), 21; https://doi.org/10.3390/antib14010021 - 3 Mar 2025

Abstract

Background: Macrophages play an important role in eliminating diseased and damaged cells through programmed cell death. Signal regulatory protein alpha (SIRPα) is a crucial immune checkpoint primarily expressed on myeloid cells and macrophages. It initiates a ‘do not eat me’ signal when engaged [...] Read more.

Background: Macrophages play an important role in eliminating diseased and damaged cells through programmed cell death. Signal regulatory protein alpha (SIRPα) is a crucial immune checkpoint primarily expressed on myeloid cells and macrophages. It initiates a ‘do not eat me’ signal when engaged with CD47, which is typically expressed at elevated levels on multiple solid tumors. The phospholipase A2 Group 7 (PLA2G7), which is mainly secreted by macrophages, interacts with oxidized low-density lipoprotein (oxLDL) and associates with several vascular diseases and cancers. Methods: To identify potent fully human monoclonal antibodies (mAbs) against human SIRPα and PLA2G7, we conducted bio-panning of phage antibody libraries. Results: We isolated one human Fab (1B3) and VH (1A3) for SIRPα, as well as one human Fab (1H8) and one VH (1A9) for PLA2G7; the 1B3 Fab and 1A3 VH are competitively bound to SIRPα, interfering with CD47 binding. The 1B3 IgG and 1A3 VH-Fc augmented macrophage-mediated phagocytic activity when combined with the anti-EGFR antibody, cetuximab. The anti-PLA2G7 antibodies exhibited high specificity for the PLA2G7 antigen and effectively blocked the PLA2G7 enzymatic activity with half-maximal inhibitory concentrations (IC₅₀) in the single-digit nanomolar range. Additionally, 1H8 IgG and its derivative bispecific antibody exhibited the ability to block PLA2G7-mediated tumor cell migration. Conclusions: Our anti-SIRPα mAbs are expected to serve as potent and fully human immune checkpoint inhibitors of SIRPα, enhancing the antitumor responses of SIRPα-positive immune cells. Moreover, our anti-PLA2G7 mAbs represent promising fully human PLA2G7 enzymatic blockade antibodies with the potential to enhance both anti-tumor and anti-aging responses. Anti-SIRPα and PLA2G7 mAbs can modulate macrophage phagocytic activity and inflammatory responses against tumors. Full article

(This article belongs to the Section Antibody-Based Therapeutics)

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23 pages, 1025 KiB

Open AccessReview

Monoclonal Antibodies in Light of Mpox Outbreak: Current Research, Therapeutic Targets, and Animal Models

by Vladimir N. Nikitin, Iuliia A. Merkuleva and Dmitriy N. Shcherbakov

Antibodies 2025, 14(1), 20; https://doi.org/10.3390/antib14010020 - 26 Feb 2025

Abstract

The rapid rise in monkeypox virus infections among humans from 2022 to 2024 has captured the attention of the global healthcare community. In light of the lack of mandatory vaccination and limited data on next-generation vaccines for monkeypox prevention, the urgent development of [...] Read more.

The rapid rise in monkeypox virus infections among humans from 2022 to 2024 has captured the attention of the global healthcare community. In light of the lack of mandatory vaccination and limited data on next-generation vaccines for monkeypox prevention, the urgent development of therapeutic agents has become a priority. One promising approach involves the use of neutralizing monoclonal antibodies. This review highlights significant advancements in the search for antibodies against human pathogenic orthopoxviruses, particularly focusing on their potential application against the monkeypox virus. We also analyze viral proteins that serve as targets for identifying therapeutic antibodies capable of neutralizing a wide range of viruses. Finally, we deemed it essential to address the challenges associated with selecting an animal model that can adequately reflect the infectious process of each orthopoxvirus species in humans. Full article

(This article belongs to the Special Issue Therapeutic Antibodies: New Trends in Discovery, Developability and Characterization)

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11 pages, 1086 KiB

Open AccessArticle

IgE-Crosslinking-Induced Luciferase Expression Test as a Sensitive Indicator of Anisakis Allergy

by Haruyo Akiyama, Masashi Niwa, Chisato Kurisaka, Yuto Hamada, Yuma Fukutomi and Reiko Teshima

Antibodies 2025, 14(1), 19; https://doi.org/10.3390/antib14010019 - 25 Feb 2025

Abstract

Background: Anisakis allergy has been increasing, and the diagnosis of it is based on specific serum IgE detection. Recently, the IgE-crosslinking-induced luciferase expression (EXiLE) test has been proposed as convenient tool for detecting functionally specific IgE antibodies. Here, we investigated if the [...] Read more.

Background: Anisakis allergy has been increasing, and the diagnosis of it is based on specific serum IgE detection. Recently, the IgE-crosslinking-induced luciferase expression (EXiLE) test has been proposed as convenient tool for detecting functionally specific IgE antibodies. Here, we investigated if the EXiLE test is a useful tool in the diagnosis of Anisakis allergy. Methods: HuRa-40 cells were sensitized using six serum types from three patients with Anisakis allergy at the time of the initial test and after 6–12 months. Thereafter, various concentrations of Anisakis worm protein (AWP) were reacted to measure the degree of EXiLE. The degree of EXiLE was compared with Anisakis-specific IgE antibody levels measured by the CAP-FEIA method, and the IgE-antibody-binding protein profile was examined using IgE immunoblotting. Results: The results showed a good correlation between the CAP-FEIA values and EXiLE obtained with 5 μg/mL of AWP (R = 0.91, p < 0.01), a strong response on IgE immunoblotting in the region containing proteins weighing ≥40,000 Da. In addition, after the onset of Anisakis allergy, the degree of serum EXiLE decreased in two patients whose Anisakis-specific IgE antibody levels decreased over time but increased in one patient whose specific IgE antibodies increased after repeated antigen sensitization. Conclusions: Based on these data, the AWP-induced EXiLE test seemed to be useful and convenient for the diagnosis of Anisakis allergy, supplementing specific IgE determinants. After allergy onset, the use of this method to observe changes in specific IgE levels over time may be important for predicting the risk of recurrence. Full article

(This article belongs to the Section Antibody-Based Diagnostics)

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17 pages, 2302 KiB

Open AccessReview

Avian Antibodies as Potential Therapeutic Tools

by Mats Eriksson and Anders Larsson

Antibodies 2025, 14(1), 18; https://doi.org/10.3390/antib14010018 - 14 Feb 2025

Abstract

Immunoglobulin Y (IgY) is the primary antibody found in the eggs of chicken (Gallus domesticus), allowing for large-scale antibody production with high titers, making them cost-effective antibody producers. IgY serves as a valuable alternative to mammalian antibodies typically used in immunodiagnostics [...] Read more.

Immunoglobulin Y (IgY) is the primary antibody found in the eggs of chicken (Gallus domesticus), allowing for large-scale antibody production with high titers, making them cost-effective antibody producers. IgY serves as a valuable alternative to mammalian antibodies typically used in immunodiagnostics and immunotherapy. Compared to mammalian antibodies, IgY offers several biochemical advantages, and its straightforward purification from egg yolk eliminates the need for invasive procedures like blood collection, reducing stress in animals. Due to the evolutionary differences between birds and mammals, chicken antibodies can bind to a broader range of epitopes on mammalian proteins than their mammalian counterparts. Studies have shown that chicken antibodies bind 3–5 times more effectively to rabbit IgG than swine antibodies, enhancing the signal in immunological assays. Additionally, IgY does not interact with rheumatoid factors or human anti-mouse IgG antibodies (HAMA), helping to minimize interference from these factors. IgY obtained from egg yolk of hens immunized against Pseudomonas aeruginosa has been used in patients suffering from cystic fibrosis and chronic pulmonary colonization with this bacterium. Furthermore, IgY has been used to counteract streptococcus mutans in the oral cavity and for the treatment of enteral infections in both humans and animals. However, the use of avian antibodies is limited to pulmonary, enteral, or topical application and should, due to immunogenicity, not be used for systemic administration. Thus, IgY expands the range of strategies available for combating pathogens in medicine, as a promising candidate both as an alternative to antibiotics and as a valuable tool in research and diagnostics. Full article

(This article belongs to the Special Issue Therapeutic Antibodies: New Trends in Discovery, Developability and Characterization)

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