Search Results (1,448)

Single-domain antibodies (sdAbs) are the smallest antigen-binding antibody (Ab) fragments (12–15 kDa) and have emerged as a versatile therapeutic platform. Their compact size, high solubility, stability, and ability to access cryptic epitopes distinguish them from conventional monoclonal Abs (mAbs) and larger Ab fragments. These properties are particularly attractive in ophthalmology, where molecular size, tissue penetration, and formulation constraints critically influence therapeutic performance. This narrative review summarizes the structural features, engineering strategies, immunogenicity considerations, and production platforms of sdAbs, with a focus on ocular applications. Preclinical studies demonstrate promising efficacy in retinal vascular diseases through targeting of VEGFA, ANG2, TNFα, and complement components, as well as in inflammatory and anterior segment disorders. SdAbs can be formatted as multimeric or Fc-fused constructs to extend intraocular half-life or delivered via gene therapy vectors as a sustained intraocular “biofactory” approach. Notably, recent work demonstrates the feasibility of vector-encoded sdAbs targeting complement C3 in vivo. While challenges remain regarding immunogenicity, pharmacokinetics, and regulatory pathways, the approval of several sdAb-based drugs in other fields underscores their clinical potential. SdAbs represent a promising next-generation modality for ocular therapeutics, enabling innovative strategies beyond conventional antibody formats. Full article

Background/Objectives: Colistin (COL), administered as a prodrug colistimethate sodium (CMS), is commonly used to treat infections caused by multidrug-resistant Gram-negative bacteria in critically ill patients. Given high CMS instability, very complex and variable pharmacokinetics (PK) and high incidence of toxicity, therapeutic drug monitoring (TDM) of active COL might play an important role. This study aimed to develop and validate an accessible immunoassay-based approach for COL monitoring in human serum. Methods: A direct competitive enzyme-linked immunosorbent assay (dcELISA) was developed using polyclonal (pAb) anti-polymyxin antibody alongside a polymyxin B–horseradish peroxidase conjugate. CMS conversion to COL along with serum deproteinization was achieved using 5% trichloroacetic acid (TCA) treatment at 37 °C. Assay accuracy and precision were assessed by spike-and-recovery experiments in healthy volunteer serum. The assay was applied to serum samples from critically ill patients with burns or pneumonia receiving CMS therapy. The reliability of the measurements was confirmed by parallel dcELISA based on a reference monoclonal antibody (mAb) against fragmented polymyxin molecule. Results: Both ELISA formats demonstrated high sensitivity, with limits of detection of 0.053 ng/mL (pAb) and 0.047 ng/mL (mAb). TCA treatment achieved maximal CMS hydrolysis under tested conditions within one hour. Clinical sample analysis showed excellent agreement between the two assays (R² = 0.996), with Bland–Altman analysis revealing a minimal bias of 3.7%. Exploratory PK analysis in burn patients demonstrated increased total drug volume of distribution (45.7–64.9 L) and clearance (8.3–16.3 L/h). Conclusions: This is the first report of ELISA for COL TDM in critically ill patients. The method offers acceptable analytical performance and practical simplicity, with potential to broaden TDM access beyond specialist centers. Full article

Classical swine fever (CSF), caused by the classical swine fever virus (CSFV), is an acute, febrile, and highly contagious disease that has led to significant economic losses in the global swine industry. Although the attenuated lapinized CSF vaccine (C-strain) has effectively controlled CSF outbreaks in China since the 1950s, it remains challenging to serologically differentiate infected from vaccinated animals (DIVA). Currently, the application of E2 subunit vaccines allows for DIVA by detecting antibodies against the E^rns protein. Therefore, this study aimed to develop a blocking ELISA for CSFV E^rns antibody detection using porcine monoclonal antibodies (mAbs) derived from single B cell technology. Peripheral blood mononuclear cells (PBMCs) were isolated from immunized pigs, and single CD21⁺IgM⁻E^rns-His tag⁺ B cells were sorted via flow cytometry. Using one-step PCR, full-length genes of porcine IgG heavy and light chains were amplified separately, yielding 11 porcine mAbs against the CSFV E^rns protein. Among these, three mAbs (E0S3, E0S5, and E0S10) exhibited broad reactivity, while two (E0S1, E0S4) showed no cross-reaction with bovine viral diarrhea virus (BVDV). Using mAb E0S4 as the blocking antibody, a blocking ELISA was established and optimized. The assay demonstrated a detection limit of 1:128, no cross-reactivity with other swine viruses or BVDV, and intra- and inter-assay coefficients of variation below 10%. ROC curve analysis determined an optimal cut-off value of 48.4%, with high sensitivity and specificity. In conclusion, the developed blocking ELISA provides a reliable tool for high-throughput serological surveillance, facilitating the DIVA strategy and contributing to CSF eradication programs. Full article

Monoclonal antibody (mAb) discovery has been transformed by advances in single-cell technologies, microfluidics, high-throughput sequencing, and computational design. Modern platforms enable the interrogation of large numbers of individual B cells, directly linking antibody sequence with antigen specificity and functional activity. Microfluidic and optofluidic systems now support high-throughput compartmentalisation and functional screening of antibody-secreting cells, while sequencing-based approaches allow parallel recovery of paired heavy- and light-chain sequences. These developments have shifted antibody discovery from binding-based selection toward function-first paradigms, enabling the rapid identification of diagnostic and therapeutically relevant antibodies. Integration with computational tools, including machine learning and structure-based modelling, has further enabled the emergence of closed-loop discovery pipelines, in which experimental and in silico methods iteratively refine candidates. This review summarises key advances in single-cell microtools over the last decade and highlights how the convergence of experimental and computational technologies is reshaping antibody discovery toward scalable, data-driven, and increasingly automated platforms. Full article

Neuroinflammation is increasingly recognized as a key modulator of therapeutic response and adverse events in Alzheimer’s disease (AD), especially during anti-amyloid-β (Aβ) monoclonal antibody (Aβ-mAb) treatment. We applied longitudinal translocator protein (TSPO) positron emission tomography (PET) to evaluate TSPO-associated neuroinflammatory responses to chronic Aβ-mAb therapy and their modulation by the peroxisome proliferator-activated receptor γ (PPARγ) agonist pioglitazone. App^NL-G-F knock-in mice underwent TSPO-PET and Aβ-PET imaging at 5, 7.5, and 10 months of age across four treatment arms: placebo, Aβ-mAb, pioglitazone, and combination therapy. TSPO-PET detected early and progressive neuroinflammatory responses to Aβ-mAb that appeared lower with pioglitazone co-treatment. Both mono- and combination therapy were associated with altered temporal and spatial dynamics of the TSPO-PET signal. In addition, we applied a previously validated microglia desynchronization index based on TSPO-PET connectivity, which captured individual variation in regional TSPO-PET organization and correlated with cognitive performance. Together, TSPO-PET and its regional synchronicity can quantify longitudinal, region-specific treatment effects, which may help differentiate harmful from adaptive neuroinflammatory responses. These findings highlight the potential of TSPO-PET as a stratification biomarker to optimize therapeutic interventions. TSPO-PET therefore enables in vivo tracking of treatment-associated neuroinflammatory responses during anti-Aβ immunotherapy and provides a non-invasive framework for evaluating combination strategies targeting amyloid pathology and immune regulation in AD. Full article

The pharmaceutical industry has seen significant growth in the development of antibody-based therapeutics, especially monoclonal antibodies (mAbs) and bispecific antibodies (bsAbs), used in the treatment of cancer and neurodegenerative diseases. However, their production and purification remain challenging. It is difficult to achieve both high product yield and the strict purity required for clinical use. Downstream processing is expensive and often involves trade-offs between efficiency and product quality. In addition, current purification methods do not fully remove contaminants, especially host cell proteins, residual DNA, and protein aggregates, affecting the safety and effectiveness of the final product. Recent advances in purification technologies, such as improved chromatography techniques and alternative separation methods, have shown promise in addressing some of these limitations. Process optimization and the integration of continuous manufacturing approaches are being explored to enhance efficiency and scalability. Furthermore, increased regulatory expectations are driving the need for more robust and reproducible purification strategies. As the antibody therapeutics market continues to expand, optimizing manufacturing and purification processes is crucial to achieve cost efficiency and large-scale production. This article discusses the main challenges in antibody production and downstream purification, focusing on monoclonal and bispecific antibodies, and compares current strategies to increase yield, improve purity, and reduce contaminants. Full article

Background/Objectives: The envelope (E) protein of orthoflaviviruses contains antigenic sites that are composed of one or more epitopes, which can vary in antigenic specificity, including between viral species, strains, and even substrains. Monoclonal antibodies (mAbs) that bind these epitopes vary in functionality based on their specificity. This makes mAbs useful to study the differences in phenotypes between strains of viruses, such as the wild type (WT) and live attenuated vaccine strains of yellow fever virus (YFV). mAb 2D12 was raised against the 17D-204 YFV vaccine substrain virus (YF VAX^®) by Schlesinger et al. in 1983. However, it only neutralizes Asibi WT virus, not the 17D-204 vaccine substrain virus. Results: We confirmed these results and demonstrated that mAb 2D12 fails to neutralize all 17D vaccine substrains (17D-204, 17DD, and 17D-213), indicating that the minor differences between these virus substrains do not affect the epitope or functionality of mAb 2D12. In addition, mAb 2D12 was found to neutralize WT strain of French viscerotropic virus (FVV), with statistically indistinguishable neutralization from the WT strain Asibi. All but one of the live attenuated French neurotropic vaccine (FNV) derivative viruses had significantly lower neutralization than WT strains Asibi and FVV. FVV, Asibi, 17D, and FNV have many amino acid differences in the membrane (M) and E proteins. It is unclear which of them contributes to this differential neutralization. However, FNV and 17D have common amino acid substitutions from WT FVV and Asibi at positions M-36 and E-331, suggesting that one or both of these residues may contribute to the 2D12 epitope. Conclusions: Overall, mAb 2D12 is a valuable tool to distinguish WT virulent strains of YFV from live attenuated vaccine strains. Full article

Background/Objectives: Cadherin-13 (CDH13), part of the cadherin family, is attached to the plasma membrane through glycosylphosphatidylinositol. CDH13 plays essential roles in the development of the neurological and vascular systems and is a risk factor for neural and cardiovascular diseases. CDH13 is expressed on the plasma membrane in both mature and uncleaved precursor forms with the prodomain. Although several anti-CDH13 monoclonal antibodies (mAbs) are available for basic research, there have been no reports of anti-CDH13 mAbs that can detect both the mature form and the uncleaved precursor in flow cytometry. Methods: We developed novel anti-human CDH13 mAbs (named Ca₁₃Mabs) using the mature form of CDH13-expressed cells as an antigen. Results: Among Ca₁₃Mabs, a clone, Ca₁₃Mab-17 (IgG_2b, κ) specifically recognized the mature and uncleaved precursor CDH13-overexpressed Chinese hamster ovary-K1 (CHO/CDH13) cells with no detectable cross-reactivity toward 21 other cadherins by flow cytometry. Ca₁₃Mab-17 also detected endogenous CDH13 in human glioblastoma (LN229 and U87MG) and lung mesothelioma (NCI-H2052) cell lines. The dissociation constant (K_D) value of Ca₁₃Mab-17 for LN229 was estimated at 4.1 × 10⁻⁸ M. Furthermore, Ca₁₃Mab-17 detected both the mature and uncleaved precursor CDH13 in Western blotting. It also identified new blood vessels and glioblastoma cells by immunohistochemistry. Conclusions: Ca₁₃Mab-17 is a versatile tool for detecting both mature and uncleaved precursor forms of CDH13 and has potential for tumor diagnosis and therapy. Full article

Glypican-1 (GPC1) has emerged as a critical mediator of malignant tumor progression. GPC1 plays essential roles in regulating various signaling pathways involved in tumor cell proliferation, invasiveness, and tumorigenesis. Overexpression of GPC1 in tumors mediates oncogenic transformation, epithelial-to-mesenchymal transition, metastatic dissemination, and therapeutic resistance. Accordingly, GPC1-targeted therapeutic strategies have been investigated in clinical and preclinical studies. However, clinical efficacy has been limited. We previously developed an anti-GPC1 monoclonal antibody (mAb), G₁Mab-28 (mouse IgG₁, κ), which exhibits high affinity and specificity for GPC1. In the present study, we generated recombinant isotype-converted G₁Mab-28, including G₁Mab-28-mG_2a (mouse IgG_2a) and G₁Mab-28-hG₁ (human IgG₁). Both mAbs recognized GPC1-expressing human tumor cell lines, including lung squamous cell carcinoma PC-10 and pancreatic ductal adenocarcinoma PK-45H, by flow cytometry. Moreover, both mAbs exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against those cell lines. In mouse xenograft models, treatment with the mAbs resulted in potent antitumor efficacy against PC-10 and PK-45H tumors. Collectively, these findings support the therapeutic potential of G₁Mab-28 for the treatment of GPC1-positive tumors. Full article

Nowadays, optical fiber-based biosensors are widely used in various fields, particularly in medical diagnostics and the selection of appropriate treatments for certain diseases. One example is cerebral ischemic disease, where many biomarkers are released and provide valuable information about the severity and progression of the disease. In this study, a long-period fiber grating (LPFG) biosensor was developed using a standard single-mode optical fiber and monoclonal antibody (IL-6 mAb) as the biological recognition element to detect IL-6, which is a protein associated with the inflammatory process. The assembly of the LPFG biosensor was characterized through optical and electronic microscopy to observe morphological changes at different stages of fabrication and the detection process. Additionally, micro-infrared spectroscopy was employed to identify functional groups in the protein region linked to the presence of IL-6. Experimental data were analyzed using principal component analysis, confirming the biosensor’s ability to detect IL-6 and providing insights into its fabrication process. Full article

Advanced gastric (GAC) or gastroesophageal junction (GEJAC) adenocarcinoma continues to carry a poor prognosis. Understanding GAC/GEJAC at the molecular level has provided a new understanding and the basis for individualized approaches to treatment. The current biomarker-driven therapy focuses on four areas: microsatellite instability (MSI), human epidermal growth factor receptor-2 (HER2), programmed death ligand-1 (PD-L1) combined positive score, and claudin 18.2 (CLDN18.2). However, because of improving technology, the focus has shifted to cancer cell-surface proteins and peptides. Each of these GAC/GEJAC subgroups provides a different treatment pathway. The agents utilized to treat advanced GAC/GEJAC include immune checkpoint inhibitors (ICIs), chemotherapy, monoclonal antibodies (mAbs), and antibody–drug conjugate (ADC) therapy, as well as bispecific antibodies (BsAbs), but they are certainly not limited to the above. Drug development has shifted in recent years to establish different mechanisms that are attempting more sophisticated and targeted approaches, such as BsAbs and ADCs. Meanwhile, the development of cytotoxics has tapered off. Along with these developments in drug therapy, more therapies directed at CLDN18.2, HER2, MSI, EGFR, HER3 and trophoblast cell-surface antigen 2 (TROP2) are underway. Here we review future areas in advanced GAC, including zanidatamab’s potential role in HER2-positive advanced GAC and deciphering the abundance of anti-CLDN18.2, extending beyond investigative therapies. Full article

Background/Objectives: Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway are effective drugs for migraine prevention. The worsening of symptoms after treatment discontinuation has raised the question of whether these agents are associated with sustained central neurophysiological adaptation. This study investigated treatment-associated changes in sensory processing and cortical network efficiency during preventive treatment with CGRP monoclonal antibodies (mAbs). Methods: Twenty-two patients with episodic migraine (21 female, 46.2 ± 13.8 years) and 22 age- and sex-matched healthy controls underwent visual and somatosensory evoked-potential (VEP, SSEP) assessments and quantitative electroencephalography (qEEG). Patients were investigated before treatment initiation (V0) and after 3 months of CGRP mAb treatment (V3). Healthy controls were assessed once. Results: The lack of habituation of VEPs at V0 shifted toward habituation at V3 following treatment with CGRP mAbs (Δslope: −0.37 ± 0.83, p = 0.03). VEP habituation at V3 no longer differed significantly from controls. SSEP amplitudes remained stable and did not differ significantly between groups across the study interval. Exploratory qEEG parameters indicated a less efficient cortical network organization at V0 that was no longer significantly different from controls at V3. Conclusions: Three months of CGRP mAb treatment was associated with a partial normalization of selected neurophysiological parameters, particularly VEP habituation and exploratory qEEG network measures. Given the study design and small sample size, these findings indicate adaptive changes in multi-domain processing, yet these should not be overinterpreted as proof of disease modification. Full article

Background/Objectives: Glypican-1 (GPC1) is a heparan sulfate proteoglycan that plays a critical role in regulating various signaling pathways and tumor development. Overexpression of GPC1 promotes tumor cell proliferation and invasiveness, and is associated with poor clinical outcomes. Therefore, anti-GPC1 monoclonal antibodies (mAbs) have been developed in various modalities for tumor therapy. Methods: We developed novel anti-GPC1 mAbs using a flow cytometry-based high-throughput screening approach, the Cell-Based Immunization and Screening (CBIS) method. Results: A clone G₁Mab-28 (IgG₁, κ) reacted with GPC1-overexpressed Chinese hamster ovary-K1 (CHO/GPC1), but not parental CHO-K1, in flow cytometry. Furthermore, G₁Mab-28 recognizes the endogenous GPC1-expressing human esophageal squamous cell carcinoma KYSE770 cell line. Furthermore, G₁Mab-28 specifically recognized only CHO/GPC1, but not the other GPC family-overexpressed CHO-K1. The dissociation constant values of G₁Mab-28 for CHO/GPC1 and KYSE770 were determined to be 3.3 × 10⁻⁸ M and 4.6 × 10⁻⁹ M, respectively. Moreover, G₁Mab-28 is suitable for Western blotting and immunohistochemistry. Conclusions: G₁Mab-28, established by the CBIS method, is versatile for basic research and is expected to contribute to antibody-based tumor therapy. Full article

A highly potent antitoxin for botulinum neurotoxin (BoNT) serotypes A and B has been developed that comprises three monoclonal antibodies (mAbs) targeting BoNT/A and three targeting BoNT/B. These oligoclonal antibody combinations neutralize toxin by simultaneously binding non-overlapping epitopes, thereby promoting rapid toxin clearance. All six mAbs use the same human Fc and framework and have been individually manufactured using the same expression platform and purification process. To minimize the time and labor required to produce the divalent antitoxin, we tested a co-expression and co-purification strategy for the three mAbs per serotype. The mAbs were expressed in CHO-K1 cells, and the media were optimized for co-expression in 10 L bioreactors. Chromatographic co-purification consisted of Protein A capture, followed by strong anion exchange chromatography in flow-through mode and cation-exchange chromatography in bind-elute mode. Co-expression experiments demonstrated that expression of the three anti-BoNT/A antibodies remained within approximately ±30% of the optimal equimolar ratio, whereas the anti-BoNT/B antibodies showed greater variability. Downstream purification steps achieved recoveries greater than 95% per chromatographic step, resulting in overall process yields of approximately 63–75%. This strategy provided sufficient purity of all six mAbs while largely preserving their relative ratios. These results demonstrate the feasibility of producing oligoclonal antitoxin antibodies using co-expression and shared purification strategies. Such approaches may simplify the manufacturing of antibody cocktails while maintaining product quality and biological activity. Full article

Trastuzumab is the first humanised monoclonal antibody (Mab) developed for breast cancer (BC) therapy. The high affinity of Trastuzumab Fab-domain binding to the human epidermal growth factor receptor 2 (HER2) receptor, with a K_d value of <1 nM, is also accompanied by Fc domain interaction with Fc-receptors in natural killer cells and leukocytes, enabling the killing of tumour cells through antibody-directed cellular cytotoxicity (ADCC). Trastuzumab blocks the over-expressed HER2 receptor-mediated dimerization and consequent intracellular signalling, leading to cancerous growth. However, the trastuzumab resistance (TR) became the major problem within 1 year of treatment. The mutation in phosphatidylinositol 3′-kinase (PI3K) pathway, cross-talk with estrogen receptors, over-expression of Mucin 1 (MUC1) protein, insulin-like growth factor I receptor, etc., are key pathways involved in TR. In this review, we have provided a molecular view of TR and the possible remedies for overcoming TR using BC stem cell (BCSC)-based therapy, PI3K pathway inhibitors, MUC1-based treatment, etc. We have also analysed the patents and clinical trials from the pre-TR and post-TR era to rationalise the possible steps to overcome TR. Our analysis implies that Trastuzumab monotherapy no longer applies to HER2+ BC treatment. Further, combination therapy using other antibodies like pertuzumab and protein kinase inhibitors and targeting pathways like the ubiquitin proteasome pathway will be the future option for BC Treatment. Overall, this review provides a detailed summary of the molecular mechanisms involving TR and its potential ways of evasion, based on updated information from published research articles, clinical trial outcomes, and patent data. Full article