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Early diagnosis of pregnancy is directly related to cost-effective livestock production. We produced a rat monoclonal antibody (mAb) against synthesized porcine early pregnancy factor (pEPF) using conventional hybridoma technology and used it as a tool for the detection of early pregnancy in Duroc sows. The rat pEPF-mAb showed reactivity to uterine tissues of pregnant sows 20 or 30 days post-mating (day 0 defined as the day of mating) and non-pregnant sows (confirmed signs of estrus) in western blotting. Immunohistochemical analysis confirmed that pEPF was located in the stromal and grand epithelial tissues of pregnant sows 20 or 30 days post-mating. In the enzyme-linked immunosorbent assay, pEPF expression in urine and blood showed similar results, with the highest expression observed in pregnant sows 20 days post-mating, whereas there was no significant difference in expression levels between non-pregnant sows and pregnant sows 30 days post-mating. The pEPF-mAb-based pregnancy diagnostic kit can be applied to pig urine samples non-invasively collected at 20 days post-mating with 70 % accuracy. Further improvements to the kit's diagnostic performance may lead to substantial benefits for the swine industry, facilitating more efficient and accurate reproductive management. • Monoclonal antibody for porcine early pregnancy factor (pEPF) was produced with hybridoma technology. • pEPF was detected in uterine tissue of pregnant sows on day 20 and found to be localized in the uterine stromal tissues. • PEPF antibody-based immunochromatographic kit was designed to diagnose Day-20 sow pregnancy using urine samples. [ABSTRACT FROM AUTHOR]

Introduction: Animal models play a vital role in pharmaceutical research and development by supporting the planning and design of later clinical studies. To improve confidence and reliability of first in human dose estimates it is essential to assess the comparability of animal studies with the human situation. In the context of large molecules, it is particularly important to evaluate the crossspecies-translatability of parameters related to neonatal fragment crystallizable receptor (FcRn) binding and target mediated drug disposition (TMDD), as they greatly influence distribution and disposition of proteins in the body of an organism. Methods: Plasma pharmacokinetic data of the therapeutic protein efalizumab were obtained from literature. Physiologically based pharmacokinetic (PBPK) models were built for three different species (rabbit, non-human primate (NHP), human). Target binding was included in the NHP and human models. The assumption of similar target turnover and target-binding in NHP and human was explored, to gain insights into how these parameters might be translated between species. Results: Efalizumab PBPK models were successfully developed for three species and concentration-time-profiles could be described appropriately across different intravenously administered doses. The final NHP and human models feature a common set of parameters for target turnover and drug-targetcomplex internalization, as well as comparable target-binding parameters. Our analyses show that different parameter values for FcRn affinity are crucial to accurately describe the concentration-time profiles. Discussion: Based on the available data in rabbits, NHP and humans, parameters for FcRn affinity cannot be translated between species, but parameters related to target mediated drug disposition can be translated from NHP to human. The inclusion of additional pharmacokinetic (PK) data including different efalizumab doses would further support and confirm our findings on identifying TMDD and, thus, binding kinetics of efalizumab in NHPs. Furthermore, we suggest that information on target expression and internalization rates could make it possible to develop comprehensive human PBPK models with minimal animal testing. In this project, we compared the pharmacokinetics of a therapeutic protein in rabbit, NHP and human using an open PBPK modeling platform (Open Systems Pharmacology Suite, http://www.open-systems-pharmacology.org). Our findings could support similar translatory studies for first in human dose predictions in the future. [ABSTRACT FROM AUTHOR]

Abstract Lumpy skin disease (LSD) is a highly contagious disease caused by lumpy skin disease virus (LSDV) in bovines. Rapid and accurate diagnosis is very important to controll it. However, current commercial detection kits need to be improved in terms of sensitivity or specificity. This study aimed to develop a novel diagnostic competitive enzyme-linked immunosorbent assay (cELISA) based on the newly identified antigen gene LSDV034. The rLSDV034 protein was identified as a potential diagnostic antigen, and it was expressed, purified, and used to immunize BALB/c mice. Using laboratory-prepared indirect ELISA (iELISA), the positive cell lines were screened, and their blocking activity was further verified by competitive ELISA (cELISA). The cell line, 1H7, was chosen to produce mouse ascites, which were purified for a monoclonal antibody (mAb, 5.395 mg/mL). The heavy chain type of the 1H7 mAb was identified as IgG1a, and its light chain subtype was identified as κ. Furthermore, cELISA was developed to detect bovine serum antibodies, with rLSDV034 (4 μg/mL) as the coating antigen and HRP-1H7 mAb (1:300) as the competitive antibody. The cutoff value of cELISA was 55%, based on 32 negative bovine serum samples. The analytical sensitivity was 1:8, and no cross-reaction was detected with bovine viral diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV), Pasteurella multocida (P. multocida), or Mycoplasma bovis (M. bovis) from the serum samples. The diagnostic sensitivity and specificity of cELISA were 98.46% (95% confidence interval, CI: 91.7–100) and 100% (95% CI: 89.1–100), respectively, based on the analysis of 30 LSDV-infected bovine serum samples, 35 GTPV-vaccinated samples, and 32 negative samples. The overall coincidence of the cELISA with the virus neutralization test (VNT) reached 98.97% (95% CI: 94.4–100). Furthermore, we used cELISA to analyze 230 clinical bovine serum samples (including 59 infected and 171 vaccinated samples) and found that the serum positivity rates of the immunized samples (on d 60 postimmunization) and infected samples were 77.78% (95% CI: 70.8–83.8%) and 71.19% (95% CI: 57.9–82.2), respectively. These results indicate that the developed cELISA is promising for detecting serum antibodies in naturally infected or vaccinated cattle.

• ZipChip native capillary electrophoresis-mass spectrometry (nCE-MS) analysis was used in forced degradation and stability studies. • Samples under thermal stress, oxidative stress, and pH stress were analyzed. • High-resolution charge variant separation was achieved by ZipChip native capillary electrophoresis. • Intact mass analysis enabled charge variant identification arising from post-translational modifications and sequence truncations. Therapeutic antibodies are a major class of biopharmaceutics that are applied in disease treatment because of their many advantages, including high specificity and high affinity to molecular targets. Between their production and administration, therapeutic antibodies are exposed to multiple stress conditions. Forced degradation and stress stability studies are conducted to simulate the risk of degradation and the effects of these stresses, thereby enhancing understanding of the drug product to support strategies to mitigate the impact from stressed conditions. These types of studies are also routinely conducted to evaluate product comparability when major process changes are implemented during the production. Charge variant analysis helps understand the changes in the electrostatic environment of biotherapeutics and can uncover underlying molecular level alterations associated with charge variants. Herein, we used ZipChip native capillary electrophoresis-mass spectrometry (nCE-MS) to elucidate the changes in charge variant profiles at the molecular level. In two case studies under thermal stress conditions, we observed that charge variants arose from both post-translational modifications (including deamidation, oxidation, and pyroglutamate formation) and sequence truncations at the hinge regions. Under oxidative stress conditions, oxidation was found to be the major contributor to the changes in the charge variant profiles. Under pH stress conditions, the changes in the charge variant profile were due to increased levels of deamidation, oxidation, and pyroglutamate formation. ZipChip nCE-MS analysis enables identification of charge variant species under various stress conditions, thus supporting process and formulation development of biotherapeutics. [ABSTRACT FROM AUTHOR]

Lumpy skin disease (LSD) is a highly contagious disease caused by lumpy skin disease virus (LSDV) in bovines. Rapid and accurate diagnosis is very important to controll it. However, current commercial detection kits need to be improved in terms of sensitivity or specificity. This study aimed to develop a novel diagnostic competitive enzyme-linked immunosorbent assay (cELISA) based on the newly identified antigen gene LSDV034. The rLSDV034 protein was identified as a potential diagnostic antigen, and it was expressed, purified, and used to immunize BALB/c mice. Using laboratory-prepared indirect ELISA (iELISA), the positive cell lines were screened, and their blocking activity was further verified by competitive ELISA (cELISA). The cell line, 1H7, was chosen to produce mouse ascites, which were purified for a monoclonal antibody (mAb, 5.395 mg/mL). The heavy chain type of the 1H7 mAb was identified as IgG1a, and its light chain subtype was identified as κ. Furthermore, cELISA was developed to detect bovine serum antibodies, with rLSDV034 (4 μg/mL) as the coating antigen and HRP-1H7 mAb (1:300) as the competitive antibody. The cutoff value of cELISA was 55%, based on 32 negative bovine serum samples. The analytical sensitivity was 1:8, and no cross-reaction was detected with bovine viral diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV), Pasteurella multocida (P. multocida), or Mycoplasma bovis (M. bovis) from the serum samples. The diagnostic sensitivity and specificity of cELISA were 98.46% (95% confidence interval, CI: 91.7–100) and 100% (95% CI: 89.1–100), respectively, based on the analysis of 30 LSDV-infected bovine serum samples, 35 GTPV-vaccinated samples, and 32 negative samples. The overall coincidence of the cELISA with the virus neutralization test (VNT) reached 98.97% (95% CI: 94.4–100). Furthermore, we used cELISA to analyze 230 clinical bovine serum samples (including 59 infected and 171 vaccinated samples) and found that the serum positivity rates of the immunized samples (on d 60 postimmunization) and infected samples were 77.78% (95% CI: 70.8–83.8%) and 71.19% (95% CI: 57.9–82.2), respectively. These results indicate that the developed cELISA is promising for detecting serum antibodies in naturally infected or vaccinated cattle. [ABSTRACT FROM AUTHOR]

Simple Summary: The ADCC bioassays used to assess mAb-induced ADCC require continued development/refinement to meet regulatory requirements. We used trastuzumab and a lactate de-hydrogenase (LDH)-based ADCC bioassay as a model to define critical parameters of the ADCC bioassay. We find that a 4 to 24 h recovery cultivation is required to restore peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cell activity toward ADCC when using cryopreserved PBMCs. Several bioassay parameters, including preparation of effector cells, E/T ratio, target cell selection, bioassay media components, and treatment time can also influence the data quality of the ADCC activity. The mechanisms of mAb-induced ADCC have been well established. However, the ADCC bioassays used to quantify mAb-induced ADCC require continued development/refinement to properly assess and compare the potency of newly developed therapeutic mAbs and biosimilars to meet regulatory requirements. We used trastuzumab and a lactate dehydrogenase (LDH)-based ADCC bioassay as a model to define critical parameters of the ADCC bioassay, describing how several bioassay parameters, including preparation of effector cells, E/T ratio, target cell selection, bioassay media components, and treatment time can influence the data quality of the ADCC activity. We confirm that a 4 to 24 h recovery cultivation is required to restore peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cell activity toward ADCC when using cryopreserved PBMCs. Furthermore, we delineated the cellular mechanisms underlying the restored ADCC activity following the recovery cultivation. We observed that CD69, an early marker of NK cell activation, was upregulated and a new subset CD56dim/CD16dim population was dramatically increased in the recovered NK cells, which led to an increase in expression and secretion of perforin, granzyme B, and cytokine production. This study provides comprehensive technical insights into ADCC bioassay optimization to inform trastuzumab biosimilar development. The knowledge gained from this study can also be leveraged to guide bioassay development for therapeutic mAbs with ADCC as the primary mechanism of action. [ABSTRACT FROM AUTHOR]

Canine atopic dermatitis (CAD) is an allergic, inflammatory, and pruritic skin disease associated with the production of IgE antibodies against environmental allergens and mainly house dust mite allergens. This complex dermatological pathology involves Interleukin 31 (IL-31) as a central itch mediator. One of the most effective CAD treatments is a caninized monoclonal antibody (mAb) called Lokivetmab. It is produced in CHO cells and targets specifically canine IL-31 (cIL-31) and blocks its cellular messaging. This treatment has undoubtedly contributed to a breakthrough in dermatitis-related pruritus. However, its production in mammalian cells requires time-consuming procedures, high production costs, and investment. Plants are considered an emerging protein production platform for recombinant biopharmaceuticals due to their cost-effectiveness and rapidity for production. Here, we use transient expression in Nicotiana benthamiana plants to produce recombinant canine Interleukin 31 (cIL-31) and an anti-IL-31 monoclonal antibody (M1). First, we describe the production and characterization of M1 and then its activity on an IL-31-induced pruritic model in dogs compared to its commercial homolog. Dogs treated with the plant-made M1 mAb have shown similar improvements to Lokivetmab-treated ones after different challenges using canine IL-31. Furthermore, M1 injections were not associated with any side effects. These results demonstrate the safety and efficacy of this plant-made Lokivetmab biosimilar to control dogs' pruritus in a well-established model. Finally, this study shows that the plant-production platform can be utilized to produce rapidly functional mAbs and bring hope to the immunotherapy field of veterinary medicine. [ABSTRACT FROM AUTHOR]

IntroductionAnimal models play a vital role in pharmaceutical research and development by supporting the planning and design of later clinical studies. To improve confidence and reliability of first in human dose estimates it is essential to assess the comparability of animal studies with the human situation. In the context of large molecules, it is particularly important to evaluate the cross-species-translatability of parameters related to neonatal fragment crystallizable receptor (FcRn) binding and target mediated drug disposition (TMDD), as they greatly influence distribution and disposition of proteins in the body of an organism.MethodsPlasma pharmacokinetic data of the therapeutic protein efalizumab were obtained from literature. Physiologically based pharmacokinetic (PBPK) models were built for three different species (rabbit, non-human primate (NHP), human). Target binding was included in the NHP and human models. The assumption of similar target turnover and target-binding in NHP and human was explored, to gain insights into how these parameters might be translated between species.ResultsEfalizumab PBPK models were successfully developed for three species and concentration-time-profiles could be described appropriately across different intravenously administered doses. The final NHP and human models feature a common set of parameters for target turnover and drug-target-complex internalization, as well as comparable target-binding parameters. Our analyses show that different parameter values for FcRn affinity are crucial to accurately describe the concentration-time profiles.DiscussionBased on the available data in rabbits, NHP and humans, parameters for FcRn affinity cannot be translated between species, but parameters related to target mediated drug disposition can be translated from NHP to human. The inclusion of additional pharmacokinetic (PK) data including different efalizumab doses would further support and confirm our findings on identifying TMDD and, thus, binding kinetics of efalizumab in NHPs. Furthermore, we suggest that information on target expression and internalization rates could make it possible to develop comprehensive human PBPK models with minimal animal testing. In this project, we compared the pharmacokinetics of a therapeutic protein in rabbit, NHP and human using an open PBPK modeling platform (Open Systems Pharmacology Suite, http://www.open-systems-pharmacology.org). Our findings could support similar translatory studies for first in human dose predictions in the future.

Aflatoxins (AFs) including AFB1, AFB2, AFG1 and AFG2 are widely found in agriculture products, and AFB1 is considered one of the most toxic and harmful mycotoxins. Herein, a highly sensitive (at the pg mL−1 level) and group-specific enzyme-linked immunosorbent assay (ELISA) for the detection of AFB1 in agricultural and aquiculture products was developed. The AFB1 derivative containing a carboxylic group was synthesized and covalently linked to bovine serum albumin (BSA). The AFB1-BSA conjugate was used as an immunogen to immunize mice. A high-quality monoclonal antibody (mAb) against AFB1 was produced by hybridoma technology, and the mAb-based ELISA for AFB1 was established. IC50 and limit of detection (LOD) of the ELISA for AFB1 were 90 pg mL−1 and 18 pg mL−1, respectively. The cross-reactivities (CRs) of the assay with AFB2, AFG1, and AFG2 were 23.6%, 42.5%, and 1.9%, respectively, revealing some degree of group specificity. Corn flour, wheat flour, and crab roe samples spiked with different contents of AFB1 were subjected to ELISA procedures. The recoveries and relative standard deviation (RSD) of the ELISA for AFB1 in spiked samples were 78.3–116.6% and 1.49–13.21% (n = 3), respectively. Wheat flour samples spiked with the mixed AF (AFB1, AFB2, AFG1, AFG2) standard solution were measured by ELISA and LC-MS/MS simultaneously. It was demonstrated that the proposed ELISA can be used as a screening method for evaluation of AFs (AFB1, AFB2, AFG1, AFG2) in wheat flour samples. [ABSTRACT FROM AUTHOR]

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Background3-caffeoylquinic acid (3-CQA), a member of the chlorogenic acid family, possesses diverse pharmacological properties, such as scavenging, antioxidant, and antiapoptotic activity, rendering substantial value to alimentary consumables and therapeutic substances. However, the pervasiveness of non-standard practices, notably the misuse and abuse of indigenous botanicals, coupled with the inherent susceptibility of 3-CQA to degradation under light and heat exposure, engenders discernible disparateness in the quality profiles of the same kinds of herbs. Consequently, precise quantification of 3-CQA becomes imperative.MethodsIn this context, an artificial antigen was synthesized as a specific conjugate of 3-CQA and bovine serum albumin (3-CQA-BSA), followed by the generation of a monoclonal antibody (mAb) against the conjugate. Through optimization, a mAb-based indirect competitive chemiluminescence enzyme immunoassay (ic-CLEIA) was developed.ResultsIt demonstrated an IC50 and the calibration range of 2.97 ng/mL and 0.64–13.75 ng/mL, respectively, outperforming the conventional enzyme-linked immunosorbent assay (ELISA). Notably, the ic-CLEIA displayed 10.71% cross-reactivity with 3,5-dicaffeoylquinic acid, alongside minimal cross-reactivity toward other isomeric counterparts and analogs. Validation experiments on herbs and Chinese patent medicines using ic-CLEIA, confirmed by high-performance liquid chromatography (HPLC) analysis, revealed a robust correlation coefficient of 0.9667 between the two modalities.ConclusionThese findings unequivocally demonstrated that the proposed ic-CLEIA represents a viable and reliable analytical method for 3-CQA determination. This method holds significant potential for ensuring the quality control and therapeutic efficacy germane to herbs and patent medicines, spanning diverse therapeutic milieus and applications.

Purpose: Monoclonal antibodies (mAbs), like other protein therapeutics, are prone to various forms of degradation, some of which are difficult to distinguish from the native form yet may alter potency. A generalizable LC–MS approach was developed to enable quantitative analysis of isoAsp. In-depth understanding of product quality attributes (PQAs) enables optimization of the manufacturing process, better formulation selection, and decreases risk associated with product handling in the clinic or during shipment. Methods: Reversed-phase chromatographic peak splitting was observed when a mAb was exposed to elevated temperatures. Multiple LC–MS based methods were applied to identify the reason for peak splitting. The approach involved the use of complementary HPLC columns, multiple enzymatic digestions and different MS/MS ion dissociation methods. In addition, mAb potency was measured by enzyme-linked immunosorbent assay (ELISA). Results: The split peaks had identical masses, and the root cause of the peak splitting was identified as isomerization of an aspartic acid located in the complementarity-determining region (CDR) of the light chain. And the early eluting and late eluting peaks were collected and performed enzymatic digestion to confirm the isoAsp enrichment in the early eluting peak. In addition, decreased potency was observed in the same heat-stressed sample, and the increased isoAsp levels in the CDR correlate well with a decrease of potency. Conclusion: Liquid chromatography-mass spectrometry (LC–MS) has been utilized extensively to assess PQAs of biological therapeutics. In this study, a generalizable LC–MS-based approach was developed to enable identification and quantitation of the isoAsp-containing peptides. [ABSTRACT FROM AUTHOR]

Canine atopic dermatitis (CAD) is an allergic, inflammatory, and pruritic skin disease associated with the production of IgE antibodies against environmental allergens and mainly house dust mite allergens. This complex dermatological pathology involves Interleukin 31 (IL-31) as a central itch mediator. One of the most effective CAD treatments is a caninized monoclonal antibody (mAb) called Lokivetmab. It is produced in CHO cells and targets specifically canine IL-31 (cIL-31) and blocks its cellular messaging. This treatment has undoubtedly contributed to a breakthrough in dermatitis-related pruritus. However, its production in mammalian cells requires time-consuming procedures, high production costs, and investment. Plants are considered an emerging protein production platform for recombinant biopharmaceuticals due to their cost-effectiveness and rapidity for production. Here, we use transient expression in Nicotiana benthamiana plants to produce recombinant canine Interleukin 31 (cIL-31) and an anti-IL-31 monoclonal antibody (M1). First, we describe the production and characterization of M1 and then its activity on an IL-31-induced pruritic model in dogs compared to its commercial homolog. Dogs treated with the plant-made M1 mAb have shown similar improvements to Lokivetmab-treated ones after different challenges using canine IL-31. Furthermore, M1 injections were not associated with any side effects. These results demonstrate the safety and efficacy of this plant-made Lokivetmab biosimilar to control dogs’ pruritus in a well-established model. Finally, this study shows that the plant-production platform can be utilized to produce rapidly functional mAbs and bring hope to the immunotherapy field of veterinary medicine.

Chronic hepatitis B is a global public health problem, and coinfection with hepatitis delta virus (HDV) worsens disease outcome. Here, we describe a hepatitis B virus (HBV) surface antigen (HBsAg)-targeting monoclonal antibody (mAb) with the potential to treat chronic hepatitis B and chronic hepatitis D. HBsAg-specific mAbs were isolated from memory B cells of HBV vaccinated individuals. In vitro neutralization was determined against HBV and HDV enveloped with HBsAg representing eight HBV genotypes. Human liver-chimeric mice were treated twice weekly with a candidate mAb starting 3 weeks post HBV inoculation (spreading phase) or during stable HBV or HBV/HDV coinfection (chronic phase). From a panel of human anti-HBs mAbs, VIR-3434 was selected and engineered for pre-clinical development. VIR-3434 targets a conserved, conformational epitope within the antigenic loop of HBsAg and neutralized HBV and HDV infection with higher potency than hepatitis B immunoglobulins in vitro. Neutralization was pan-genotypic against strains representative of HBV genotypes A-H. In the spreading phase of HBV infection in human liver-chimeric mice, a parental mAb of VIR-3434 (HBC34) prevented HBV dissemination and the increase in intrahepatic HBV RNA and covalently closed circular DNA. In the chronic phase of HBV infection or co-infection with HDV, HBC34 treatment decreased circulating HBsAg by >1 log and HDV RNA by >2 logs. The potently neutralizing anti-HBs mAb VIR-3434 reduces circulating HBsAg and HBV/HDV viremia in human liver-chimeric mice. VIR-3434 is currently in clinical development for treatment of patients with chronic hepatitis B or D. Chronic infection with hepatitis B virus and co-infection with hepatitis D virus place approximately 290 million individuals worldwide at risk of severe liver disease and cancer. Available treatments result in low rates of functional cure or require lifelong therapy that does not eliminate the risk of liver disease. We isolated and characterized a potent human antibody that neutralizes hepatitis B and D viruses and reduces infection in a mouse model. This antibody could provide a new treatment for patients with chronic hepatitis B and D. [Display omitted] • Identification of a human mAb VIR-3434 that potently neutralizes HBV and HDV. • VIR-3434 targets a conserved, conformational epitope of the HBsAg antigenic loop. • VIR-3434 treatment blocks intrahepatic HBV spread in human liver-chimeric mice. • VIR-3434 treatment reduces circulating HBsAg and HDV RNA in co-infected mice. • Data have enabled clinical development of VIR-3434 against chronic hepatitis B/D. [ABSTRACT FROM AUTHOR]

In an ever-increasing aged world, Alzheimer's disease (AD) represents the first cause of dementia and one of the first chronic diseases in elderly people. With 55 million people affected, the WHO considers AD to be a disease with public priority. Unfortunately, there are no final cures for this pathology. Treatment strategies are aimed to mitigate symptoms, i.e., acetylcholinesterase inhibitors (AChEI) and the N-Methyl-D-aspartate (NMDA) antagonist Memantine. At present, the best approaches for managing the disease seem to combine pharmacological and non-pharmacological therapies to stimulate cognitive reserve. Over the last twenty years, a number of drugs have been discovered acting on the well-established biological hallmarks of AD, deposition of β-amyloid aggregates and accumulation of hyperphosphorylated tau protein in cells. Although previous efforts disappointed expectations, a new era in treating AD has been working its way recently. The Food and Drug Administration (FDA) gave conditional approval of the first disease-modifying therapy (DMT) for the treatment of AD, aducanumab, a monoclonal antibody (mAb) designed against Aβ plaques and oligomers in 2021, and in January 2023, the FDA granted accelerated approval for a second monoclonal antibody, Lecanemab. This review describes ongoing clinical trials with DMTs and non-pharmacological therapies. We will also present a future scenario based on new biomarkers that can detect AD in preclinical or prodromal stages, identify people at risk of developing AD, and allow an early and curative treatment. [ABSTRACT FROM AUTHOR]

Objective: This study was to evaluate the feasibility of using a rocking type bioreactor system, specifically the WAVE 25, in an intensified perfusion culture (IPC) mode for monoclonal antibody (mAb) production in Chinese hamster ovary (CHO) cell line. Methods: A disposable perfusion bag with floating membrane was used in the IPC process. An automated filter switching system was employed to continuously clarify the harvested post-membrane culture fluid. The overall cell culture performance, product titer, and quality were compared to those of a typical IPC conducted in a bench-top glass bioreactor. Results: The results showed that the overall trends of cell culture performance, product titer (accumulated harvest volumetric titer) were similar to those of the typical IPC conducted in the glass bioreactor, while the purity related quality were slightly better than the typical run. Furthermore, with the automated filter switching system, the harvested post-membrane culture fluid could be continuously clarified, making it suitable for downstream continuous chromatography. Conclusion: The study demonstrated the feasibility of using the WAVE-based rocking type bioreactor in the N stage IPC process, which increases the flexibility in adopting IPC process. The results suggest that the rocking type bioreactor system could be a viable alternative to traditional stirred tank bioreactors for perfusion culture in the biopharmaceutical industry. [ABSTRACT FROM AUTHOR]

Aflatoxins (AFs) including AFB1, AFB2, AFG1 and AFG2 are widely found in agriculture products, and AFB1 is considered one of the most toxic and harmful mycotoxins. Herein, a highly sensitive (at the pg mL−1 level) and group-specific enzyme-linked immunosorbent assay (ELISA) for the detection of AFB1 in agricultural and aquiculture products was developed. The AFB1 derivative containing a carboxylic group was synthesized and covalently linked to bovine serum albumin (BSA). The AFB1-BSA conjugate was used as an immunogen to immunize mice. A high-quality monoclonal antibody (mAb) against AFB1 was produced by hybridoma technology, and the mAb-based ELISA for AFB1 was established. IC50 and limit of detection (LOD) of the ELISA for AFB1 were 90 pg mL−1 and 18 pg mL−1, respectively. The cross-reactivities (CRs) of the assay with AFB2, AFG1, and AFG2 were 23.6%, 42.5%, and 1.9%, respectively, revealing some degree of group specificity. Corn flour, wheat flour, and crab roe samples spiked with different contents of AFB1 were subjected to ELISA procedures. The recoveries and relative standard deviation (RSD) of the ELISA for AFB1 in spiked samples were 78.3–116.6% and 1.49–13.21% (n = 3), respectively. Wheat flour samples spiked with the mixed AF (AFB1, AFB2, AFG1, AFG2) standard solution were measured by ELISA and LC-MS/MS simultaneously. It was demonstrated that the proposed ELISA can be used as a screening method for evaluation of AFs (AFB1, AFB2, AFG1, AFG2) in wheat flour samples.

N-glycan engineering has dramatically evolved for the development and quality control of recombinant antibodies. Fc region of IgG contains two N-glycans whose galactose terminals on Fc-glycan have been shown to increase the stability of CH2 domain and improve effector functions. Nicotiana benthamiana has become one of the most attractive production systems for therapeutic antibodies. In this study, Varlilumab, a CD27-targeting monoclonal antibody, was transiently produced in fresh leaves of soil-grown and hydroponic-grown N. benthamiana, resulted in the yield of 174 and 618 µg/ gram, respectively. However, the IgG produced in wild-type N. benthamiana lacked the terminal galactose residues in its N-glycan. Therefore, N-glycan engineering was applied to fine-tune recombinant antibodies produced in plant platforms. We further co-expressed IgG together with murine b1,4- galactosyltransferase (b1,4-GALT) to modify plant N-glycan with b1,4-linked Gal residue(s) and Arabidopsis thaliana b1,3-galactosylatransferase (b1,3-GALT) to improve galactosylation. The co-expression of IgG with each of GALTs successfully resulted in modification of N-glycan structures on the plantproduced IgG. Notably, IgG co-expressed with murine b1,4-GALT in soilgrown N. benthamiana had 42.5% of N-glycans variants having galactose (Gal) residues at the non-reducing terminus and 55.3% of that in hydroponic-grown N. benthamiana plants. Concomitantly, N-glycan profile analysis of IgG coexpressed with b1,3-GALT demonstrated that there was an increased efficiency of galactosylation and an enhancement in the formation of Lewis a structure in plant-derived antibodies. Taken together, our findings show that the first plantderived Varlilumab was successfully produced with biantennary b1,4- galactosylated N-glycan structures. [ABSTRACT FROM AUTHOR]

In this study, an extremely highly sensitive enzyme-linked immunosorbent assay (ELISA) based on a newly produced monoclonal antibody (mAb) for the detection of ochratoxin A (OTA) in food samples was developed. OTA-Bovine serum albumin (BSA) conjugate was prepared and used as the immunogen for the production of the mAb. Among four hybridoma clones (8B10, 5C2, 9B7, and 5E11), the antibody from 8B10 displayed the highest affinity recognition for OTA. Based on the mAb (8B10), the IC50 and LOD of the ELISA for OTA were 34.8 pg mL−1 and 1.5 pg mL−1, respectively, which was 1.53~147 times lower than those in published ELISAs, indicating the ultra-sensitivity of our assay. There was no cross-reactivity of the mAb with the other four mycotoxins (AFB1, ZEN, DON, and T-2). Due to the high similarity in molecular structures among OTA, ochratoxin B (OTB), and ochratoxin C (OTC), the CR values of the mAb with OTB and OTC were 96.67% and 22.02%, respectively. Taking this advantage, the ELISA may be able to evaluate total ochratoxin levels in food samples. The recoveries of the ELISA for OTA in spiked samples (corn, wheat, and feed) were 96.5–110.8%, 89.5–94.4%, and 91.8–113.3%; and the RSDs were 5.2–13.6%, 8.2–13.0%, and 7.7–13.7% (n = 3), respectively. The spiked food samples (corn) were measured by ELISA and HPLC-FLD simultaneously. A good correlation between ELISA (x) and HPLC-FLD (y) with the linear regression equation of y = 0.918x − 0.034 (R2 = 0.985, n = 5) was obtained. These results demonstrated that the newly produced mAb-based ELISA was a feasible and ultra-sensitive analytical method for the detection of OTA in food samples. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a common cause of hospital-acquired infections, including central line-associated bloodstream infections and ventilatorassociated pneumonia. Unfortunately, effective control of these infections can be difficult, in part due to the prevalence of multi-drug resistant strains of P. aeruginosa. There remains a need for novel therapeutic interventions against P. aeruginosa, and the use of monoclonal antibodies (mAb) is a promising alternative strategy to current standard of care treatments such as antibiotics. To develop mAbs against P. aeruginosa, we utilized ammonium metavanadate, which induces cell envelope stress responses and upregulates polysaccharide expression. Mice were immunized with P. aeruginosa grown with ammonium metavanadate and we developed two IgG2b mAbs, WVDC-0357 and WVDC- 0496, directed against the O-antigen lipopolysaccharide of P. aeruginosa. Functional assays revealed that WVDC-0357 and WVDC-0496 directly reduced the viability of P. aeruginosa and mediated bacterial agglutination. In a lethal sepsis model of infection, prophylactic treatment of mice with WVDC-0357 and WVDC-0496 at doses as low as 15 mg/kg conferred 100% survival against challenge. In both sepsis and acute pneumonia models of infection, treatment with WVDC-0357 and WVDC-0496 significantly reduced bacterial burden and inflammatory cytokine production post-challenge. Furthermore, histopathological examination of the lungs revealed that WVDC-0357 and WVDC-0496 reduced inflammatory cell infiltration. Overall, our results indicate that mAbs directed against lipopolysaccharide are a promising therapy for the treatment and prevention of P. aeruginosa infections. [ABSTRACT FROM AUTHOR]

Simple Summary: Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that uses photoreactive agents and light irradiation, while photodynamic therapy (PDT) is an existing phototherapy using photosensitizers and light irradiation as well as NIR-PIT. The current study investigated the properties of these therapies and their differences with a focus on their cellular binding/uptake specificity and cytotoxicity in vitro. NIR-PIT showed molecule-selective responses and cytotoxicity, whereas PDT showed non-selective cell type responses and cytotoxicity. Additionally, NIR-PIT and PDT induced damage-associated molecular patterns (DAMPs), a surrogate marker of immunogenic cell death, although PDT had different sensitivity between cell lines. Therefore, molecule-specific NIR-PIT may have advantages compared with PDT in terms of efficiency in tumor visualization and induction of DAMPs. Near-infrared photoimmunotherapy (NIR-PIT) is a new phototherapy that utilizes a monoclonal antibody (mAb) against cancer antigens and a phthalocyanine dye, IRDye700DX (IR700) conjugate (mAb-IR700). Photodynamic therapy (PDT) is a combination therapy that utilizes photoreactive agents and light irradiation as well as NIR-PIT. In the present study, we compared these therapies in vitro. The characterization of cellular binding/uptake specificity and cytotoxicity were examined using two mAb-IR700 forms and a conventional PDT agent, talaporfin sodium, in three cell lines. As designed, mAb-IR700 had high molecular selectivity and visualized target molecule-positive cells at the lowest concentration examined. NIR-PIT induced necrosis and damage-associated molecular patterns (DAMPs), a surrogate maker of immunogenic cell death. In contrast, talaporfin sodium was taken up by cells regardless of cell type, and its uptake was enhanced in a concentration-dependent manner. PDT induced cell death, with the pattern of cell death shifting from apoptosis to necrosis depending on the concentration of the photosensitizer. Induction of DAMPs was observed at the highest concentration, but their sensitivity differed among cell lines. Overall, our data suggest that molecule-specific NIR-PIT may have potential advantages compared with PDT in terms of the efficiency of tumor visualization and induction of DAMPs. [ABSTRACT FROM AUTHOR]

The 2022 global outbreaks of monkeypox virus (MPXV) and increased human-to-human transmission calls for the urgent development of countermeasures to protect people who cannot benefit from vaccination. Here, we describe the development of glycovariants of 7D11, a neutralizing monoclonal IgG antibody (mAb) directed against the L1 transmembrane protein of the related vaccinia virus, in a plant-based system as a potential therapeutic against the current MPVX outbreak. Our results indicated that 7D11 mAb quickly accumulates to high levels within a week after gene introduction to plants. Plant-produced 7D11 mAb assembled correctly into the tetrameric IgG structure and can be easily purified to homogeneity. 7D11 mAb exhibited a largely homogeneous N-glycosylation profile, with or without plant-specific xylose and fucose residues, depending on the expression host, namely wild-type or glycoengineered plants. Plant-made 7D11 retained specific binding to its antigen and displayed a strong neutralization activity against MPXV, as least as potent as the reported activity against vaccinia virus. Our study highlights the utility of anti-L1 mAbs as MPXV therapeutics, and the use of glycoengineered plants to develop mAb glycovariants for potentially enhancing the efficacy of mAbs to combat ever-emerging/re-emerging viral diseases. [ABSTRACT FROM AUTHOR]

Chinese Hamster Ovary cells have been widely used as host cells for production of recombinant therapeutic molecules. Cell line development is a decisive step, which must be carried out with an efficient process. In particular, degree of selection stringency is an important parameter for identification of rare, high-producing cell lines. In the CHOZN® CHO K1 platform, selection of top-producing clones is based on puromycin resistance, whose expression is driven by Simian Virus 40 Early (SV40E) promoter. In this study, novel promoters have been identified to drive expression of selection marker. Decrease of transcriptional activity compared to SV40E promoter was confirmed by RT-qPCR. Selection stringency was increased, as seen by decreased surviving rate of transfected mini-pools and longer recovery duration of transfected bulk pools. Several promoters led to a 1.5-fold increase of maximum titer and a 1.3-fold increase of mean specific productivity of the monoclonal antibody over the clone generation. Expression level was maintained stable over long term cultivation. Finally, productivity increase was confirmed on several monoclonal antibodies and fusion proteins. Lowering the strength of promoter for expression of selective pressure resistance is an efficient strategy to increase selection stringency, which can be applied on industrial CHO-based cell line development platforms. • Attenuated SV40 and CHO endogenous promoters to lower selection marker expression. • Cell recovery correlated to selection marker expression under puromycin selection. • Increased selection stringency leads to selection of higher mAb producing cells. • Robustness confirmed on therapeutic relevant proteins such as mAb or Fc-proteins. • Optimization of selection process in industrial CHO-cell line development platforms. [ABSTRACT FROM AUTHOR]

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Antibody-dependent enhancement of infection (ADE) is clinically relevant to Dengue virus (DENV) infection and poses a major risk to the application of monoclonal antibody (mAb)-based therapeutics against related flaviviruses such as the Zika virus (ZIKV). Here, we tested a two-tier approach for selecting non-cross-reactive mAbs combined with modulating Fc glycosylation as a strategy to doubly secure the elimination of ADE while preserving Fc effector functions. To this end, we selected a ZIKV-specific mAb (ZV54) and generated three ZV54 variants using Chinese hamster ovary cells and wild-type (WT) and glycoengineered ΔXF Nicotiana benthamiana plants as production hosts (ZV54CHO, ZV54WT, and ZV54ΔXF). The three ZV54 variants shared an identical polypeptide backbone, but each exhibited a distinct Fc N-glycosylation profile. All three ZV54 variants showed similar neutralization potency against ZIKV but no ADE activity for DENV infection, validating the importance of selecting the virus/serotype-specific mAbs for avoiding ADE by related flaviviruses. For ZIKV infection, however, ZV54CHO and ZV54ΔXF showed significant ADE activity while ZV54WT completely forwent ADE, suggesting that Fc glycan modulation may yield mAb glycoforms that abrogate ADE even for homologous viruses. In contrast to the current strategies for Fc mutations that abrogate all effector functions along with ADE, our approach allowed the preservation of effector functions as all ZV54 glycovariants retained antibody-dependent cellular cytotoxicity (ADCC) against the ZIKV-infected cells. Furthermore, the ADE-free ZV54WT demonstrated in vivo efficacy in a ZIKV-infection mouse model. Collectively, our study provides further support for the hypothesis that antibody–viral surface antigen and Fc-mediated host cell interactions are both prerequisites for ADE, and that a dual-approach strategy, as shown herein, contributes to the development of highly safe and efficacious anti-ZIKV mAb therapeutics. Our findings may be impactful to other ADE-prone viruses, including SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAb) against the envelope (E) protein of Zika virus (ZIKV) have shown great potential as therapeutics against the Zika epidemics. However, their use as a therapy may predispose treated individuals to severe infection by the related dengue virus (DENV) via antibody-dependent enhancement of infection (ADE). Here, we generated a broadly neutralizing flavivirus mAb, ZV1, with an identical protein backbone but different Fc glycosylation profiles. The three glycovariants, produced in wild-type (WT) and glycoengineered ΔXF Nicotiana benthamiana plants and in Chinese hamster ovary cells (ZV1WT, ZV1ΔXF, and ZV1CHO), respectively, showed equivalent neutralization potency against both ZIKV and DENV. By contrast, the three mAb glycoforms demonstrated drastically different ADE activity for DENV and ZIKV infection. While ZV1CHO and ZV1ΔXF showed ADE activity upon DENV and ZIKV infection, ZV1WT totally forwent its ADE. Importantly, all three glycovariants exhibited antibody-dependent cellular cytotoxicity (ADCC) against virus-infected cells, with increased potency by the fucose-free ZV1ΔXF glycoform. Moreover, the in vivo efficacy of the ADE-free ZV1WT was demonstrated in a murine model. Collectively, we demonstrated the feasibility of modulating ADE by Fc glycosylation, thereby establishing a novel approach for improving the safety of flavivirus therapeutics. Our study also underscores the versatile use of plants for the rapid expression of complex human proteins to reveal novel insight into antibody function and viral pathogenesis. [ABSTRACT FROM AUTHOR]

Summary: This study describes a novel, neutralizing monoclonal antibody (mAb), 11D7, discovered by mouse immunization and hybridoma generation, against the parental Wuhan‐Hu‐1 RBD of SARS‐CoV‐2. We further developed this mAb into a chimeric human IgG and recombinantly expressed it in plants to produce a mAb with human‐like, highly homogenous N‐linked glycans that has potential to impart greater potency and safety as a therapeutic. The epitope of 11D7 was mapped by competitive binding with well‐characterized mAbs, suggesting that it is a Class 4 RBD‐binding mAb that binds to the RBD outside the ACE2 binding site. Of note, 11D7 maintains recognition against the B.1.1.529 (Omicron) RBD, as well neutralizing activity. We also provide evidence that this novel mAb may be useful in providing additional synergy to established antibody cocktails, such as Evusheld™ containing the antibodies tixagevimab and cilgavimab, against the Omicron variant. Taken together, 11D7 is a unique mAb that neutralizes SARS‐CoV‐2 through a mechanism that is not typical among developed therapeutic mAbs and by being produced in ΔXFT Nicotiana benthamiana plants, highlights the potential of plants to be an economic and safety‐friendly alternative platform for generating mAbs to address the evolving SARS‐CoV‐2 crisis. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a common cause of hospital-acquired infections, including central line-associated bloodstream infections and ventilator-associated pneumonia. Unfortunately, effective control of these infections can be difficult, in part due to the prevalence of multi-drug resistant strains of P. aeruginosa. There remains a need for novel therapeutic interventions against P. aeruginosa, and the use of monoclonal antibodies (mAb) is a promising alternative strategy to current standard of care treatments such as antibiotics. To develop mAbs against P. aeruginosa, we utilized ammonium metavanadate, which induces cell envelope stress responses and upregulates polysaccharide expression. Mice were immunized with P. aeruginosa grown with ammonium metavanadate and we developed two IgG2b mAbs, WVDC-0357 and WVDC-0496, directed against the O-antigen lipopolysaccharide of P. aeruginosa. Functional assays revealed that WVDC-0357 and WVDC-0496 directly reduced the viability of P. aeruginosa and mediated bacterial agglutination. In a lethal sepsis model of infection, prophylactic treatment of mice with WVDC-0357 and WVDC-0496 at doses as low as 15 mg/kg conferred 100% survival against challenge. In both sepsis and acute pneumonia models of infection, treatment with WVDC-0357 and WVDC-0496 significantly reduced bacterial burden and inflammatory cytokine production post-challenge. Furthermore, histopathological examination of the lungs revealed that WVDC-0357 and WVDC-0496 reduced inflammatory cell infiltration. Overall, our results indicate that mAbs directed against lipopolysaccharide are a promising therapy for the treatment and prevention of P. aeruginosa infections.

Abstract Background Acinetobacter baumannii is an opportunistic and antibiotic-resistant pathogen that predominantly causes nosocomial infections. There is urgent need for development nonantibiotic-based treatment strategies. We developed a novel monoclonal antibody (mAb) against a peptide of conserved outer membrane protein A (OmpA) and evaluated its reactivity with different pulsotypes of A. baumannii. Methods Peptide derived from A. baumannii OmpA was conjugated to keyhole limpet hemocyanin and injected into BALB/c mice. Splenocytes of immunized mice were fused with SP2/0 myeloma cells followed by selection of antibody-producing hybridoma cells. After screening of different hybridoma colonies by ELISA, one monoclone was selected as 3F10-C9 and the antibody was tested for reaction with five different Acinetobacter pulsotypes that were resistant to carbapenem antibiotics. The affinity constant was measured by ELISA. The ELISA, western blotting, indirect immunofluorescence (IFA), and in vitro opsonophagocytosis assays were used to evaluate the reactivity of generated mAb. Results The anti-OmpA antibody reacted with the immunizing peptide and had a high affinity (1.94 × 10−9 M) for its antigen in the ELISA. Specific binding of mAb to OmpA was confirmed in Western blot. IFA assays revealed that mAb recognized specific OmpA on the pulsotypes. Opsonophagocytosis assays showed that the mAb increased the bactericidal activity of macrophage cells. The antibody function was higher in the presence of serum complement. Conclusions The peptide-based mAb demonstrated optimal performance in laboratory experiments which may be appropriate in investigation on OmpA in Acinetobacter pathogenesis and development of passive immunization as a novel therapeutic approach.

Monoclonal antibodies (mAbs) have been used as a rescue strategy for pregnant women affected by COVID-19. To explore its impact on maternal-fetal health, we included all observational studies reporting maternal, fetal, delivery and neonatal outcomes in women who underwent mAbs infusion for COVID-19. Primary outcome was the percentage of preterm delivery. We used meta-analyses of proportions to combine data for maternal, fetal, delivery and neonatal outcome of women treated with mAbs for COVID-19 and reported pooled proportions and their 95% confidence intervals (CIs) for categorical variables or mean difference (MD) with their 95% confidence intervals for continuous variables. Preterm birth was observed in 22.8% of cases (95% CI 12.9–34.3). Fetal distress was reported in 4.2% (95% CI 1.6–8.2). Gestational hypertension and pre-eclampsia were observed in 3.0% (95% CI 0.8–6.8) and 3.4% (95% CI 0.8–7.5) of cases, respectively. Fetal growth restriction was observed in 3.2% of fetuses (95% CI 0.8–7.0). Secondary prophylaxis with mAbs is currently considered the best treatment option for people with mild to moderate COVID-19 disease. More attention should be paid to infants born from mothers who were treated with mAbs, for the risk of immunosuppression. [ABSTRACT FROM AUTHOR]

A point-of-care (POC) diagnostic is needed for both women and men to establish universal screening and surveillance for the number one, non-viral sexually transmitted infection (STI) caused by Trichomonas vaginalis. We developed a POC diagnostic for this STI using the MedMira Rapid Vertical Flow (RVF®) Technology test cartridge with a membrane that includes a Vertical procedural/reagent control line (referred to as CVL) and spotted with 1 µg of a 72.4-kDa truncated version of α-actinin called ACT::SOE3. This protein is a specific diagnostic target for antibody in sera of individuals with trichomoniasis. Serum antibody to ACT::SOE3 is a positive reaction with the test spot. Specificity of ACT::SOE3 was revealed with monoclonal antibodies (MAbs) generated to ACT::SOE3. Addition of negative control serum with MAb 67B reactive to ACT::SOE3 shows detection of both ACT::SOE3 and the CVL. Only positive sera of individuals had antibody reactive with ACT::SOE3 and detected the presence of the spot and the CVL. Negative control sera were unreactive with ACT::SOE3 and only showed the presence of the CVL. Importantly, to show proof-of-principle for POC application, ACT::SOE3 was detected with the positive patient sera spiked with whole blood. Finally, packaged cartridges stored with desiccant packs at 37 °C for one year gave identical results with the positive and negative human sera. Our results show the validity of this new POC serodiagnostic for this STI. [ABSTRACT FROM AUTHOR]

A monoclonal antibody's (mAb) glycosylation pattern has a significant impact on its binding affinity to the FcγRIIIa receptor and thus on antibody-dependent cell-mediated cytotoxicity. However, to analyze the relation in cell cultures, complex sample preparation is required. In this study, we demonstrate the analytical capability of a two-dimensional liquid chromatography–mass spectrometry (2D-HPLC–HRMS) method to analyze the affinity of mAbs to the FcγRIIIa receptor while simultaneously characterizing the glycoforms involved. Results were comparable in purified samples and cell culture-free supernatants. This was demonstrated with the monoclonal antibodies adalimumab, pertuzumab, ustekinumab, tocilizumab and omalizumab. Our method hence renders extensive purification of mAb samples superfluous. [ABSTRACT FROM AUTHOR]

Abstract The claudin18.2 (CLDN18.2) protein, an isoform of claudin18, a member of the tight junction protein family, is a highly selective biomarker with limited expression in normal tissues and often abnormal expression during the occurrence and development of various primary malignant tumors, such as gastric cancer/gastroesophageal junction (GC/GEJ) cancer, breast cancer, colon cancer, liver cancer, head and neck cancer, bronchial cancer and non-small-cell lung cancer. CLDN18.2 participates in the proliferation, differentiation and migration of tumor cells. Recent studies have identified CLDN18.2 expression as a potential specific marker for the diagnosis and treatment of these tumors. With its specific expression pattern, CLDN18.2 has become a unique molecule for targeted therapy in different cancers, especially in GC; for example, agents such as zolbetuximab (claudiximab, IMAB362), a monoclonal antibody (mAb) against CLDN18.2, have been developed. In this review, we outline recent advances in the development of immunotherapy strategies targeting CLDN18.2, including monoclonal antibodies (mAbs), bispecific antibodies (BsAbs), chimeric antigen receptor T (CAR-T) cells redirected to target CLDN18.2, and antibody–drug conjugates (ADCs).

Charge heterogeneity is a critical quality attribute for therapeutic biologics including antibody-drug conjugates (ADCs). Developing an ion exchange chromatography (IEX) or an imaged capillary isoelectric focusing (icIEF) method for ADCs with high drug-to-antibody ratio (DAR) is challenging because of the increased hydrophobicity from the payload-linker, DAR heterogeneity, and payload-linker instability. A sub-optimal method can be poorly stability-indicating due to the inability to discern contributions from charge and size variants conjugated with different number of drugs/payloads. Systematic strategy and guidance on charge variant method development is highly desired for high DAR ADCs with various complex structures. This work encompasses the development and optimization of icIEF methods for high DAR ADCs of various DAR values (4–8) and payload linker chemistry. Method optimization focuses on improving resolution and stability indicating capabilities and differentiating contributions from the protein and payload-linker. Types, proportion, and combination of solubilizers and carrier ampholytes, as well as focusing parameters were interrogated. Our findings show that the structural units of the linker, the DAR, and the payload chemistry prescribe the selection of buffer, solubilizer, and ampholyte. We demonstrate that a stronger denaturant or solubilizer is needed for high DAR ADCs with polyethylene glycol (PEG)-containing linker structure compared to peptide linker. For unstable payload-linker, buffer system enhances sample stability which is vital to method robustness. In addition, a longer isoelectric focusing time is necessary for an ADC than its corresponding antibody to reach optimal focusing. To the best of our knowledge, this is the first comprehensive study on icIEF method development for charge variant determination of high DAR ADCs with unique physicochemical properties. [Display omitted] • icIEF methods were systematically investigated and optimized for high DAR ADCs. • Rational selection of ampholytes and denaturants improved charge separation. • Method parameter optimization enhanced method robustness. • Chromatographic fractionation allowed identification of a fragmented icIEF peak. • Best practices and guidelines for icIEF development of high DAR ADCs are provided. [ABSTRACT FROM AUTHOR]

In an ever-increasing aged world, Alzheimer’s disease (AD) represents the first cause of dementia and one of the first chronic diseases in elderly people. With 55 million people affected, the WHO considers AD to be a disease with public priority. Unfortunately, there are no final cures for this pathology. Treatment strategies are aimed to mitigate symptoms, i.e., acetylcholinesterase inhibitors (AChEI) and the N-Methyl-D-aspartate (NMDA) antagonist Memantine. At present, the best approaches for managing the disease seem to combine pharmacological and non-pharmacological therapies to stimulate cognitive reserve. Over the last twenty years, a number of drugs have been discovered acting on the well-established biological hallmarks of AD, deposition of β-amyloid aggregates and accumulation of hyperphosphorylated tau protein in cells. Although previous efforts disappointed expectations, a new era in treating AD has been working its way recently. The Food and Drug Administration (FDA) gave conditional approval of the first disease-modifying therapy (DMT) for the treatment of AD, aducanumab, a monoclonal antibody (mAb) designed against Aβ plaques and oligomers in 2021, and in January 2023, the FDA granted accelerated approval for a second monoclonal antibody, Lecanemab. This review describes ongoing clinical trials with DMTs and non-pharmacological therapies. We will also present a future scenario based on new biomarkers that can detect AD in preclinical or prodromal stages, identify people at risk of developing AD, and allow an early and curative treatment.

Advances in antibody engineering have enabled the construction of novel molecular formats in diverse shapes and sizes, providing new opportunities for biologic therapies and expanding the need to understand how various structural aspects affect their distribution properties. To assess the effect of antibody size on systemic pharmacokinetics (PK) and tissue distribution with or without neonatal Fc receptor (FcRn) binding, we evaluated a series of non-mouse-binding anti-glycoprotein D monoclonal antibody formats, including IgG [~150 kDa], one-armed IgG [~100 kDa], IgG-HAHQ (attenuated FcRn binding) [~150 kDa], F(ab’)2 [~100 kDa], and F(ab) [~50 kDa]. Tissue-specific concentration–time profiles were corrected for blood content based on vascular volumes and normalized based on interstitial volumes to allow estimation of interstitial concentrations and interstitial:serum concentration ratios. Blood correction demonstrated that the contribution of circulating antibody on total uptake was greatest at early time points and for highly vascularized tissues. Tissue interstitial PK largely mirrored serum exposure profiles. Similar interstitial:serum ratios were obtained for the two FcRn-binding molecules, IgG and one-armed IgG, which reached pseudo-steady-state kinetics in most tissues. For non-FcRn-binding molecules, interstitial:serum ratios changed over time, suggesting that these molecules did not reach steady-state kinetics during the study. Furthermore, concentration–time profiles of both intact and catabolized molecule were measured by a dual tracer approach, enabling quantification of tissue catabolism and demonstrating that catabolism levels were highest for IgG-HAHQ. Overall, these data sets provide insight into factors affecting preclinical distribution and may be useful in estimating interstitial concentrations and/or catabolism in human tissues.

Echovirus 3 (E3), a serotype of human enterovirus B (HEV-B), causes severe diseases in infants. Here, we determined the structures of E3 with a monoclonal antibody (MAb) 6D10 by cryo-EM to comprehensively understand the specificities and the immunological characteristic of this serotype. The solved cryo-EM structures of the F-, A-, and E-particles of E3 bound with 6D10 revealed the structural features of the virus–antibody interface. Importantly, the structures of E-particles bound with 6D10 revealed for the first time the nature of the C-terminus of VP1 for HEV-Bs at the structural level. The highly immunogenic nature of this region in the E-particles provides new strategies for vaccine development for HEV-Bs. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) targeting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein have demonstrated clinical efficacy in preventing or treating coronavirus disease 2019 (COVID-19), resulting in the emergency use authorization (EUA) for several SARS-CoV-2 targeting mAb by regulatory authority. However, the continuous virus evolution requires diverse mAb options to combat variants. Here we describe two fully human mAbs, amubarvimab (BRII-196) and romlusevimab (BRII-198) that bind to noncompeting epitopes on the receptor binding domain (RBD) of spike protein and effectively neutralize SARS-CoV-2 variants. A YTE modification was introduced to the fragment crystallizable (Fc) region of both mAbs to prolong serum half-life and reduce effector function. The amubarvimab and romlusevimab combination retained activity against most mutations associated with reduced susceptibility to previously authorized mAbs and against variants containing amino acid substitutions in their epitope regions. Consistently, the combination of amubarvimab and romlusevimab effectively neutralized a wide range of viruses including most variants of concern and interest in vitro. In a Syrian golden hamster model of SARS-CoV-2 infection, animals receiving combination of amubarvimab and romlusevimab either pre- or post-infection demonstrated less weight loss, significantly decreased viral load in the lungs, and reduced lung pathology compared to controls. These preclinical findings support their development as an antibody cocktail therapeutic option against COVID-19 in the clinic. [ABSTRACT FROM AUTHOR]

Due to the complex manufacturing process of therapeutic monoclonal antibodies, it is hardly possible to produce an identical copy of the original product (originator). Consequently, follow-on products (biosimilars) must demonstrate their efficacy being similar to the originator in terms of structure and function. During this process, a variety of analytical methods are required for this purpose. This study focuses on three particularly relevant analytical techniques: high-resolution mass spectrometry, fragment crystallisable (Fc) affinity chromatography, and two-dimensional peptide mapping. Each analytical method proved able to identify specific differences between originator and biosimilar. High-resolution mass spectrometry was used to characterize the glycan pattern. It was shown that a trastuzumab biosimilar did not have the G0:G0F sugar modification identified in the originator. The application of affinity chromatography to rituximab showed that originator and biosimilar interacted differently with the immobilized Fc receptor. Furthermore, 2D-HPLC peptide mapping demonstrated the influence of orthogonality of separation dimensions, leading to differentiation of a rituximab originator and biosimilar. [ABSTRACT FROM AUTHOR]

The frequent variation of influenza virus hemagglutinin (HA) antigen is the main cause of influenza pandemic. Therefore, the study of B cell epitopes of HA is of great significance in the prevention and control of influenza virus. In this study, the split vaccine of 2009 H1N1 influenza virus was used as immunogen, and the monoclonal antibodies (mAbs) were prepared by conventional hybridoma fusion and screening techniques. The characteristics of mAbs were identified by ELISA method, Western-blot test and hemagglutination inhibition test (HI). Using the obtained mAbs as a tool, the B cell epitopes of HA were predicted by ELISA blocking test, sandwich ELISA method and computer simulation method. Finally, four mAbs against HA antigen of H1N1 influenza virus were obtained. The results of ELISA and computer prediction showed that there were at least two types of epitopes on HA of influenza virus. The results of this study complemented the existing methods for predicting HA epitopes, and also provided a new method for predicting other pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Polysorbates (PS) are commonly used as stabilizers of biopharmaceuticals such as monoclonal antibodies (mAbs). However, they are prone to chemical and enzymatic degradation. The latter can be caused by residual host cell proteins (HCPs) in the drug substance. Degradation affects the functionality of the PS surfactant which can lead to formation of particles. An increasing number of publications describe enzymatic PS degradation. Significant efforts have been made to characterize HCP removal during Downstream Processing (DSP) of mAbs and to develop mitigation strategies. Here we describe the use of glycine buffer for acidic elution in Protein A affinity chromatography compared to acetate buffer, which is more commonly used in the biopharmaceutical industry. Increased turbidity was observed during pH re-adjustment after low pH virus inactivation when using glycine buffer. Analytical data suggests that this turbidity is caused by the formation of precipitates which include HCP and DNA impurities. Additionally, as a zwitterion, glycine does not contribute to conductivity; this further enhances HCP removal during anion-exchange flow-through chromatography. Although glycine is well known as a possible elution buffer for Protein A affinity chromatography, its positive impact on HCP removal and PS stability have not yet been described in literature., (© 2024 The Author(s). Biotechnology and Bioengineering published by Wiley Periodicals LLC.)

Monoclonal antibodies (mAbs) targeting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein have demonstrated clinical efficacy in preventing or treating coronavirus disease 2019 (COVID-19), resulting in the emergency use authorization (EUA) for several SARS-CoV-2 targeting mAb by regulatory authority. However, the continuous virus evolution requires diverse mAb options to combat variants. Here we describe two fully human mAbs, amubarvimab (BRII-196) and romlusevimab (BRII-198) that bind to non-competing epitopes on the receptor binding domain (RBD) of spike protein and effectively neutralize SARS-CoV-2 variants. A YTE modification was introduced to the fragment crystallizable (Fc) region of both mAbs to prolong serum half-life and reduce effector function. The amubarvimab and romlusevimab combination retained activity against most mutations associated with reduced susceptibility to previously authorized mAbs and against variants containing amino acid substitutions in their epitope regions. Consistently, the combination of amubarvimab and romlusevimab effectively neutralized a wide range of viruses including most variants of concern and interest in vitro. In a Syrian golden hamster model of SARS-CoV-2 infection, animals receiving combination of amubarvimab and romlusevimab either pre- or post-infection demonstrated less weight loss, significantly decreased viral load in the lungs, and reduced lung pathology compared to controls. These preclinical findings support their development as an antibody cocktail therapeutic option against COVID-19 in the clinic.

In this study, an extremely highly sensitive enzyme-linked immunosorbent assay (ELISA) based on a newly produced monoclonal antibody (mAb) for the detection of ochratoxin A (OTA) in food samples was developed. OTA-Bovine serum albumin (BSA) conjugate was prepared and used as the immunogen for the production of the mAb. Among four hybridoma clones (8B10, 5C2, 9B7, and 5E11), the antibody from 8B10 displayed the highest affinity recognition for OTA. Based on the mAb (8B10), the IC50 and LOD of the ELISA for OTA were 34.8 pg mL−1 and 1.5 pg mL−1, respectively, which was 1.53~147 times lower than those in published ELISAs, indicating the ultra-sensitivity of our assay. There was no cross-reactivity of the mAb with the other four mycotoxins (AFB1, ZEN, DON, and T-2). Due to the high similarity in molecular structures among OTA, ochratoxin B (OTB), and ochratoxin C (OTC), the CR values of the mAb with OTB and OTC were 96.67% and 22.02%, respectively. Taking this advantage, the ELISA may be able to evaluate total ochratoxin levels in food samples. The recoveries of the ELISA for OTA in spiked samples (corn, wheat, and feed) were 96.5–110.8%, 89.5–94.4%, and 91.8–113.3%; and the RSDs were 5.2–13.6%, 8.2–13.0%, and 7.7–13.7% (n = 3), respectively. The spiked food samples (corn) were measured by ELISA and HPLC-FLD simultaneously. A good correlation between ELISA (x) and HPLC-FLD (y) with the linear regression equation of y = 0.918x − 0.034 (R2 = 0.985, n = 5) was obtained. These results demonstrated that the newly produced mAb-based ELISA was a feasible and ultra-sensitive analytical method for the detection of OTA in food samples.

The 2022 global outbreaks of monkeypox virus (MPXV) and increased human-to-human transmission calls for the urgent development of countermeasures to protect people who cannot benefit from vaccination. Here, we describe the development of glycovariants of 7D11, a neutralizing monoclonal IgG antibody (mAb) directed against the L1 transmembrane protein of the related vaccinia virus, in a plant-based system as a potential therapeutic against the current MPVX outbreak. Our results indicated that 7D11 mAb quickly accumulates to high levels within a week after gene introduction to plants. Plant-produced 7D11 mAb assembled correctly into the tetrameric IgG structure and can be easily purified to homogeneity. 7D11 mAb exhibited a largely homogeneous N-glycosylation profile, with or without plant-specific xylose and fucose residues, depending on the expression host, namely wild-type or glycoengineered plants. Plant-made 7D11 retained specific binding to its antigen and displayed a strong neutralization activity against MPXV, as least as potent as the reported activity against vaccinia virus. Our study highlights the utility of anti-L1 mAbs as MPXV therapeutics, and the use of glycoengineered plants to develop mAb glycovariants for potentially enhancing the efficacy of mAbs to combat ever-emerging/re-emerging viral diseases.

Bioimprinting was performed against ovalbumin (OVA) to confer its binding cavities for kwakhurin (Kwa), an isoflavonoid, produced solely by Pueraria candollei var. mirifica (P. candollei). The characterization of bioimprinted-OVA (biOVA), evaluated by an enzyme-linked immunosorbent assay (ELISA), revealed that it functioned as a specific receptor for Kwa. Using biOVA, two systems, i.e., an indirect competitive ELISA (icELISA) and the even simpler and more rapid competitive enzyme-linked bioimprinted-protein assay (cELBIA), were developed as novel techniques for the quantitative analysis of Kwa in P. candollei and its related products. The two analysis methods were found to have limits of detection (LOD) of 4.0 and 2.5 µg/mL, respectively. The high reliability of the developed icELISA and cELBIA using biOVA was also demonstrated by various validation analyses. Subsequently, bioimprinting was performed using eight other proteins to investigate them as candidate scaffolds for the generation of binding cavities for Kwa. Interestingly, two bioimprinted-IgG monoclonal antibodies (biMAbs) recognized Kwa, but their original binding affinity to hapten was lost. That is, the MAbs obtained a new binding ability to Kwa in exchange for their original binding affinity, raising the possibility that biMAb could be alternatively used as a probe for the quantitative analysis of Kwa as well as biOVA. This is the first report of small molecules recognition by MAbs used as proteins for bioimprinting. [ABSTRACT FROM AUTHOR]

Background: Acinetobacter baumannii is an opportunistic and antibiotic-resistant pathogen that predominantly causes nosocomial infections. There is urgent need for development nonantibiotic-based treatment strategies. We developed a novel monoclonal antibody (mAb) against a peptide of conserved outer membrane protein A (OmpA) and evaluated its reactivity with different pulsotypes of A. baumannii. Methods: Peptide derived from A. baumannii OmpA was conjugated to keyhole limpet hemocyanin and injected into BALB/c mice. Splenocytes of immunized mice were fused with SP2/0 myeloma cells followed by selection of antibody-producing hybridoma cells. After screening of different hybridoma colonies by ELISA, one monoclone was selected as 3F10-C9 and the antibody was tested for reaction with five different Acinetobacter pulsotypes that were resistant to carbapenem antibiotics. The affinity constant was measured by ELISA. The ELISA, western blotting, indirect immunofluorescence (IFA), and in vitro opsonophagocytosis assays were used to evaluate the reactivity of generated mAb. Results: The anti-OmpA antibody reacted with the immunizing peptide and had a high affinity (1.94 × 10−9 M) for its antigen in the ELISA. Specific binding of mAb to OmpA was confirmed in Western blot. IFA assays revealed that mAb recognized specific OmpA on the pulsotypes. Opsonophagocytosis assays showed that the mAb increased the bactericidal activity of macrophage cells. The antibody function was higher in the presence of serum complement. Conclusions: The peptide-based mAb demonstrated optimal performance in laboratory experiments which may be appropriate in investigation on OmpA in Acinetobacter pathogenesis and development of passive immunization as a novel therapeutic approach. [ABSTRACT FROM AUTHOR]

Distinguishing between bull Y- and X-bearing sperm populations is advantageous for techniques using sexed bull semen. The aim of this study was to produce a single-chain fragment variable (scFv) antibody against plasma membrane epitopes on bull Y-bearing sperm. Variable heavy (VH)- and variable light (VL)-region genes generated from a hybridoma cell secreting a specific Y-bearing sperm monoclonal antibody (mAb-1F9) were cloned and expressed. The expected sizes of the DNA bands were ∼350 bp for the VH gene and ∼318 bp for the VL gene. The VH and VL genes were generated and used to construct an scFv gene (∼650 bp), which was expressed in E.coli TG1 cells and produced the corresponding soluble scFv antibody. Compared with the parent mAb-1F9, the scFv antibodies presented a high affinity for Y-bearing sperm and low cross-reactivity with X-bearing sperm. An immunofluorescence analysis confirmed that the scFv antibodies and mAb-1F9 recognize epitopes on the Y-bearing sperm surface. The fluorescence signal was strong on the plasma membrane of Y-bearing sperm but very weak for X-bearing sperm. This study aids the application and production of engineered scFv antibodies specific to Y-bearing sperm to distinguish between Y- and X-bearing sperm populations for techniques involving sexed bull semen. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) caused by African swine fever virus (ASFV) is becoming a serious threat to the swine industry worldwide. CD2v is a key pathogenic factor of ASFV and the protective antigen with low immunogenicity, whereas viral protein-based nanoparticles have advantages of precise assembly and high immunogenicity. In this study, the CD2v protein fused with Norovirus (NoV) P particle assembled into nanoparticle for improved immunogenicity. Then, CD2v protein nanoparticle and monomer CD2v protein were expressed in HEK293F cells. The former induced higher levels of antibodies, and thus highly potent monoclonal antibodies (mAbs) were generated and characterized. The highest antibody titration of mAb 10A3 reached 1:2048000, and mAb 2E9 had the highest inhibition percent of 84% when competed with ASFV positive serum. Meanwhile, all mAbs reacted specifically with the denatured CD2v protein, and the linear epitope with the location of amino acids 28th to 51st of CD2v extracellular domain sequence was identified. In summary, this study produced a highly immunogenic CD2v protein and generated high-titer mAbs, the precise location of linear epitope on the CD2v was further determined. These findings may provide a powerful help for etiology and serological detection of ASFV. • Highly immunogenic CD2v protein nanoparticle was obtained. • High-titer mAbs induced by CD2v protein nanoparticle were generated, and mAb 10A3 had the highest antibody titration of 1:2048000. • The linear epitope from the 28th to the 51st position of amino acids locating in the CD2v extracellular domain sequence was first reported. [ABSTRACT FROM AUTHOR]