Exploring parental perspectives: Maternal RSV vaccination versus infant RSV monoclonal antibody

Respiratory Syncytial Virus poses a significant global public health threat, particularly affecting infants aged less than one year of age. Recently, two forms of passive immunization against infant RSV have been developed and brought to market; nirsevimab a long-acting monoclonal antibody (mAb) and RSV-PreF, a maternal RSV vaccine. The acceptability and uptake of these products will play a pivotal role in determining the success of any national immunization strategy aimed at safeguarding infants from RSV. It is crucial at this time to reflect on the factors that influence parental decisions surrounding immunization to facilitate more informed discussions, enhance healthcare communication, and contribute to the design of effective RSV prevention strategies that resonate with the concerns and aspirations of parents worldwide.

Flow cytometric detection of leukemic blasts in Libyan pediatric patients with acute lymphoblastic leukemia

The diagnosis of acute lymphoblastic leukemia (ALL), which is the most common type of cancer in children, has become more accurate with the use of flow cytometry. Here, this technology was used to immunophenotype leukemic cells in peripheral blood samples from Libyan pediatric ALL patients. We recruited 152 newly diagnosed patients at Tripoli Medical Center (Tripoli, Libya) by morphological examination of blood and bone marrow. Twenty-three surface and cytoplasmic antigen markers were used to characterize B and T cells in circulating blood cells by four-color flow cytometry. Six children (3.9%) turned out to have biphenotypic acute leukemia, 88 (57.9%) had B ALL, and 58 (38.1%) had T ALL. There were 68 cases of pro-B ALL CD10-positive (44.7%), 8 cases of pro-B ALL CD10-negative (5.2%), 6 cases of pre-B ALL (3.9%), and 6 of mature-B ALL (3.9%). CD13 was the most commonly expressed myeloid antigen in ALL. We present immunophenotypic data for the first time describing ALL cases in Libya. The reported results indicate that the most common subtype was pro-B ALL, and the frequency of T-ALL subtype was higher compared to previous studies. Six cases were positive for both myeloid and B lymphoid markers. Our findings may provide the basis for future studies to correlate immunophenotypic profile and genetic characteristics with treatment response among ALL patients.

Neutralizing activity of anti-respiratory syncytial virus monoclonal antibody produced in Nicotiana benthamiana

Respiratory syncytial virus (RSV) is a highly contagious virus that affects the lungs and respiratory passages of many vulnerable people. It is a leading cause of lower respiratory tract infections and clinical complications, particularly among infants and elderly. It can develop into serious complications such as pneumonia and bronchiolitis. The development of RSV vaccine or immunoprophylaxis remains highly active and a global health priority. Currently, GSK's Arexvy™ vaccine is approved for the prevention of lower respiratory tract disease in older adults (>60 years). Palivizumab and currently nirsevimab are the approved monoclonal antibodies (mAbs) for RSV prevention in high-risk patients. Many studies are ongoing to develop additional therapeutic antibodies for preventing RSV infections among newborns and other susceptible groups. Recently, additional antibodies have been discovered and shown greater potential for development as therapeutic alternatives to palivizumab and nirsevimab. Plant expression platforms have proven successful in producing recombinant proteins, including antibodies, offering a potential cost-effective alternative to mammalian expression platforms. Hence in this study, an attempt was made to use a plant expression platform to produce two anti-RSV fusion (F) mAbs 5C4 and CR9501. The heavy-chain and light-chain sequences of both these antibodies were transiently expressed in Nicotiana benthamiana plants using a geminiviral vector and then purified using single-step protein A affinity column chromatography. Both these plant-produced mAbs showed specific binding to the RSV fusion protein and demonstrate effective viral neutralization activity in vitro. These preliminary findings suggest that plant-produced anti-RSV mAbs are able to neutralize RSV in vitro.

Production of monoclonal antibodies against botulinum neurotoxin in Nicotiana benthamiana

Botulism is a fatal neurologic disease caused by the botulinum toxin (BoNT) produced by Clostridium botulinum. It is a rare but highly toxic disease with symptoms, such as cramps, nausea, vomiting, diarrhea, dysphagia, respiratory failure, muscle weakness, and even death. Currently, two types of antitoxin are used: equine-derived heptavalent antitoxin and human-derived immunoglobulin (BabyBIG®). However, heptavalent treatment may result in hypersensitivity, whereas BabyBIG®, has a low yield. The present study focused on the development of three anti-BoNT monoclonal antibodies (mAbs), 1B18, C25, and M2, in Nicotiana benthamiana. The plant-expressed mAbs were purified and examined for size, purity and integrity by SDS-PAGE, western blotting and size-exclusion chromatography. Analysis showed that plant-produced anti-BoNT mAbs can fully assemble in plants, can be purified in a single purification step, and mostly remain as monomeric proteins. The efficiency of anti-BoNT mAbs binding to BoNT/A and B was then tested. Plant-produced 1B18 retained its ability to recognize both mBoNT/A1 and ciBoNT/B1. At the same time, the binding specificities of two other mAbs were determined: C25 for mBoNT/A1 and M2 for ciBoNT/B1. In conclusion, our results confirm the use of plants as an alternative platform for the production of anti-BoNT mAbs. This plant-based technology will serve as a versatile system for the development botulism immunotherapeutics.

In vivo delivery of engineered synthetic DNA-encoded SARS-CoV-2 monoclonal antibodies for pre-exposure prophylaxis in non-human primates

COVID-19 remains a major public health concern. Monoclonal antibodies have received emergency use authorization (EUA) for pre-exposure prophylaxis against COVID-19 among high-risk groups for treatment of mild to moderate COVID-19. In addition to recombinant biologics, engineered synthetic DNA-encoded antibodies (DMAb) are an important strategy for direct in vivo delivery of protective mAb. A DMAb cocktail was synthetically engineered to encode the immunoglobulin heavy and light chains of two different two different Fc-engineered anti-SARS-CoV-2 antibodies. The DMAbs were designed to enhance in vivo expression and delivered intramuscularly to cynomolgus and rhesus macaques with a modified in vivo delivery regimen. Serum levels were detected in macaques, along with specific binding to SARS-CoV-2 spike receptor binding domain protein and neutralization of multiple SARS-CoV-2 variants of concern in pseudovirus and authentic live virus assays. Prophylactic administration was protective in rhesus macaques against signs of SARS-CoV-2 (USA-WA1/2020) associated disease in the lungs. Overall, the data support further study of DNA-encoded antibodies as an additional delivery mode for prevention of COVID-19 severe disease. These data have implications for human translation of gene-encoded mAbs for emerging infectious diseases and low dose mAb delivery against COVID-19.

Development and characterization of a novel neutralizing scFv vectored immunoprophylaxis against botulinum toxin type A

Botulinum toxin is a protein toxin secreted by Clostridium botulinum that is strongly neurotoxic. Due to its characteristics of being super toxic, quick acting, and difficult to prevent, the currently reported antiviral studies focusing on monoclonal antibodies have limited effectiveness. Therefore, for the sake of effectively prevention and treatment of botulism and to maintain country biosecurity as well as the health of the population, in this study, we intend to establish a single chain antibody (scFv) targeting the carboxyl terminal binding functional domain of the botulinum neurotoxin heavy chain (BONT/AHc) of botulinum neurotoxin type A, and explore the value of a new passive immune method in antiviral research which based on adeno-associated virus (AAV) mediated vector immunoprophylaxis (VIP) strategy. The scFv small-molecular single-chain antibody sequenced, designed, constructed, expressed and purified by hybridoma has high neutralising activity and affinity level, which can lay a good foundation for the modification and development of antibody engineering drugs. In vivo experiments, AAV-mediated scFv engineering drug has good anti-BONT/A toxin neutralisation ability, has advantages of simple operation, stable expression and good efficacy, and may be one of the effective treatment strategies for long-term prevention and protection of BONT/A botulinum neurotoxin.

Human monoclonal antibody F61 nasal spray effectively protected high-risk populations from SARS-CoV-2 variants during the COVID-19 pandemic from late 2022 to early 2023 in China

Following the national dynamic zero-COVID strategy adjustment, the utilization of broad-spectrum nasal neutralizing antibodies may offer an alternative approach to controlling the outbreak of Omicron variants between late 2022 and early 2023 in China. This study involved an investigator-initiated trial (IIT) to assess the pharmacokinetic, safety and efficacy of the F61 nasal spray. A total of 2,008 participants were randomly assigned to receive F61 nasal spray (24 mg/0.8 mL/dose) or normal saline (0.8 mL/dose) and 1336 completed the follow-up in the IIT. Minimal absorption of F61 antibody into the bloodstream was detected in individuals receiving F61 nasal spray for seven consecutive days. No treatment-emergent adverse reactions of grade 3 severity or higher were reported. In the one-dose cohort, the 7-day cumulative SARS-CoV-2 infection rate was 79.0% in the F61 group and 82.6% in the placebo group, whereas, in the multiple-dose (once daily for 7 consecutive days) cohort, the rates were 6.55% in the F61 group and 23.83% in the placebo group. The laboratory-confirmed efficacy of F61 was 3.78% (-3.74%-10.75%) in the one-dose cohort and 72.19% (57.33%-81.87%) in the multiple-dose cohort. In the real-world study, 60,225 volunteers in four different regions were administered the F61 nasal spray based on the subject's wishes, over 90% efficacy rate was observed against different Omicron variants. The F61 nasal spray, with its favourable safety profile, could be a promising prophylactic monoclonal antibody against SARS-CoV-2 VOCs.

Effects of IL-34 and anti-IL-34 neutralizing mAb on alveolar bone loss in a ligature-induced model of periodontitis

Macrophage colony-stimulating factor (M-CSF) and interleukin-34 (IL-34) are ligands for the colony-stimulating factor-1  receptor (CSF-1r) expressed on the surface of monocyte/macrophage lineage cells. The importance of coordinated signaling between M-CSF/receptor activator of the nuclear factor kappa-Β ligand (RANKL) in physiological and pathological bone remodeling and alveolar bone loss in response to oral bacterial colonization is well established. However, our knowledge about the IL-34/RANKL signaling in periodontal bone loss remains limited. Recently published cohort studies have demonstrated that the expression patterns of IL-34 are dramatically elevated in gingival crevicular fluid collected from patients with periodontitis. Therefore, the present study aims to evaluate the effects of IL-34 on osteoclastogenesis in vitro and in experimental ligature-mediated model of periodontitis using male mice. Our initial in vitro study demonstrated increased RANKL-induced osteoclastogenesis of IL-34-primed osteoclast precursors (OCPs) compared to M-CSF-primed OCPs. Using an experimental model of ligature-mediated periodontitis, we further demonstrated elevated expression of IL-34 in periodontal lesions. In contrast, M-CSF levels were dramatically reduced in these periodontal lesions. Furthermore, local injections of mouse recombinant IL-34 protein significantly elevated cathepsin K activity, increased the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and promoted alveolar bone loss in periodontitis lesions. In contrast, anti-IL-34 neutralizing monoclonal antibody significantly reduced the level of alveolar bone loss and the number of TRAP-positive osteoclasts in periodontitis lesions. No beneficial effects of locally injected anti-M-CSF neutralizing antibody were observed in periodontal lesions. This study illustrates the role of IL-34 in promoting alveolar bone loss in periodontal lesions and proposes the potential of anti-IL34 monoclonal antibody (mAb)-based therapeutic regimens to suppress alveolar bone loss in periodontitis lesions.

Native ion mobility-mass spectrometry reveals the binding mechanisms of anti-amyloid therapeutic antibodies

One of the most important attributes of anti-amyloid antibodies is their selective binding to oligomeric and amyloid aggregates. However, current methods of examining the binding specificities of anti-amyloid β (Aβ) antibodies have limited ability to differentiate between complexes that form between antibodies and monomeric or oligomeric Aβ species during the dynamic Aβ aggregation process. Here, we present a high-resolution native ion-mobility mass spectrometry (nIM-MS) method to investigate complexes formed between a variety of Aβ oligomers and three Aβ-specific IgGs, namely two antibodies with relatively high conformational specificity (aducanumab and A34) and one antibody with low conformational specificity (crenezumab). We found that crenezumab primarily binds Aβ monomers, while aducanumab preferentially binds Aβ monomers and dimers and A34 preferentially binds Aβ dimers, trimers, and tetrameters. Through collision induced unfolding (CIU) analysis, our data indicate that antibody stability is increased upon Aβ binding and, surprisingly, this stabilization involves the Fc region. Together, we conclude that nIM-MS and CIU enable the identification of Aβ antibody binding stoichiometries and provide important details regarding antibody binding mechanisms.

Addition of sodium malonate alters the morphology and increases the critical flux during tangential flow filtration of precipitated immunoglobulins

Recent studies have demonstrated that one can control the packing density, and in turn the filterability, of protein precipitates by changing the pH and buffer composition of the precipitating solution to increase the structure/order within the precipitate. The objective of this study was to examine the effect of sodium malonate, which is known to enhance protein crystallizability, on the morphology of immunoglobulin precipitates formed using a combination of ZnCl2 and polyethylene glycol. The addition of sodium malonate significantly stabilized the precipitate particles as shown by an increase in melting temperature, as determined by differential scanning calorimetry, and an increase in the enthalpy of interaction, as determined by isothermal titration calorimetry. The sodium malonate also increased the selectivity of the precipitation, significantly reducing the coprecipitation of DNA from a clarified cell culture fluid. The resulting precipitate had a greater packing density and improved filterability, enabling continuous tangential flow filtration with minimal membrane fouling relative to precipitates formed under otherwise identical conditions but in the absence of sodium malonate. These results provide important insights into strategies for controlling precipitate morphology to enhance the performance of precipitation-filtration processes for the purification of therapeutic proteins.

Understanding the effects of site-specific light chain conjugation on antibody structure using hydrogen exchange-mass spectrometry (HX-MS)

Antibody drug conjugates (ADCs) represent one of the fastest growing classes of cancer therapeutics. Drug incorporation through site-specific conjugation in ADCs leads to uniform drug load and distribution. These site-specific modifications may have an impact on ADC quality attributes including protein higher order structure (HOS), which might impact safety and efficacy. In this study, we conducted a side-by-side comparison between the conjugated and unconjugated mAb. In the ADC, the linker-pyrrolobenzodiazepine was site specifically conjugated to an engineered unpaired C215 residue within the Fab domain of the light chain. Differential scanning calorimetry (DSC) and differential scanning fluorimetry (DSF) indicated a decrease in thermal stability for the CH2 transition of the ADC. Size exclusion chromatography (SEC) analysis, showed that conjugation of the mAb resulted in earlier aggregation onset and increased aggregation propensity after 4 weeks at 40 °C. Differential hydrogen-exchange mass spectrometry (HX-MS) indicated that upon conjugation, light chain residues 150-155 and 197-204, close to the conjugation site, showed significantly faster HX kinetics, suggesting an increase in backbone flexibility within this region, while heavy chain residues 32-44 exhibited significantly slower kinetics, suggesting distal stabilization of the mAb backbone.

Fluorescent and Colorimetric Dual-Readout Immunochromatographic Assay for the Detection of Phenamacril Residues in Agricultural Products

The fungicide phenamacril has been employed to manage Fusarium and mycotoxins in crops, leading to persistent residues in the environment and plants. Detecting phenamacril is pivotal for ensuring environmental and food safety. In this study, haptens and artificial antigens were synthesized to produce antiphenamacril monoclonal antibodies (mAbs). Additionally, gold nanoparticles coated with a polydopamine shell were synthesized and conjugated with mAbs, inducing fluorescence quenching in quantum dots. Moreover, a dual-readout immunochromatographic assay that combines the positive signal from fluorescence with the negative signal from colorimetry was developed to enable sensitive and precise detection of phenamacril within 10 min, achieving detection limits of 5 ng/mL. The method's reliability was affirmed by using spiked wheat flour samples, achieving a limit of quantitation of 0.05 mg/kg. This analytical platform demonstrates high sensitivity, outstanding accuracy, and robust tolerance to matrix effects, making it suitable for the rapid, onsite, quantitative screening of phenamacril residues.

High-Performance Liquid Chromatographic Quantification of the Plant Hormone Abscisic Acid at ppb Levels in Plant Samples after a Single Immunoaffinity Column Cleanup

High-performance liquid chromatography with ultraviolet detection (HPLC-UV) is a common analysis technique due to its high versatility and simple operation. In the present study, HPLC-UV detection was integrated with immunoaffinity cleanup (IAC) of the sample extracts. The matrix effect was greatly reduced, and the limit of detection was as low as 1 ng/g of free abscisic acid (ABA) in fresh plant tissues. A monoclonal antibody 3F1 (mAb 3F1) was developed to specifically recognize free ABA but not ABA analogues. The mAb 3F1-immobilized immunoaffinity column exhibited a capacity of 850 ng/mL and an elution efficiency of 88.8-105% for standards. The extraction recoveries of the column for ABA ranged from 80.4 to 108.9%. ABA content was detected in various plant samples with IAC-HPLC-UV. The results were verified with ultraperformance liquid chromatography-electrospray tandem mass spectrometry. IAC-HPLC-UV can be a sensitive and cost-efficient method for plant hormone analysis.

Identification of B-cell epitopes located on the surface in the PB2 protein of the H9N2 subtype avian influenza virus

Avian influenza (AI), caused by H9N2 subtype avian influenza virus (AIV), poses a serious threat to poultry farming and public health due to its transmissibility and pathogenicity. The PB2 protein is a major component of the viral RNA polymerase complex. It is of great importance to identify the antigenic determinants of the PB2 protein to explore the function of the PB2 protein. In this study, the PB2 sequence of H9N2 subtype AIV, from 1090 to 1689 bp, was cloned and expressed. The recombinant PB2 protein with cutting gel was used to immunize BALB/c mice. After cell fusion, the hybridoma cell lines secreting monoclonal antibodies (mAbs) targeting the PB2 protein were screened by indirect ELISA and western blotting, and the antigenic epitopes of mAbs were identified by constructing truncated overlapping fragments in the PB2 protein of H9N2 subtype AIV. The results showed that three hybridoma cell lines (4B7, 4D10, and 5H1) that stably secreted mAbs specific to the PB2 protein were screened; the heavy chain of 4B7 was IgG2α, those of 4D10 and 5H1 were IgG1, and all three mAbs had kappa light chain. Also, the minimum B-cell epitope recognized was 475LRGVRVSK482 and 528TITYSSPMMW537. Homology analysis showed that these two epitopes were conserved among the different subtypes of AIV strains and located on the surface of the PB2 protein. The above findings provide an experimental foundation for further investigation of the function of the PB2 protein and developing monoclonal antibody-based diagnostic kits.

Use of spectroscopic process analytical technology for rapid quality evaluation during preparation of CHO cell culture media

Media preparation parameters contribute significantly to media quality, cell culture performance, productivity, and product quality. Establishing proper media preparation procedures is critical for ensuring a robust CHO cell culture process. Process analytical technology (PAT) enables unique ways to quantify assessments and improve media quality. Here, cell culture media were prepared under a wide range of temperatures (40-80°C) and pH (7.6-10.0). Media quality profiles were compared using three real-time PATs: Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and excitation-emission matrix (EEM) spectroscopy. FTIR and Raman spectroscopies identified shifts in media quality under high preparation temperature (80°C) and at differing preparation pH which negatively impacted monoclonal antibody (mAb) production. In fed-batch processes for production of three different mAbs, viable cell density (VCD) and cell viability were mostly unaffected under all media preparation temperatures, while titer and cell specific productivity of mAb decreased when cultured in basal and feed media prepared at 80°C. High feed preparation pH alone was tolerated but cell growth and productivity profiles deviated from the control condition. Further, charge variants (main, acidic, basic species) and glycosylation (G0F, afucosylation, and high mannose) were examined. Statistically significant differences were observed for one or more of these quality attributes with any shifts in media preparation. In this study, we demonstrated strong associations between media preparation conditions and cell growth, productivity, and product quality. The rapid evaluation of media by PAT implementation enabled more comprehensive understanding of different parameters on media quality and consequential effects on CHO cell culture.

A fully validated LC‑MS/MS method for quantifying bevacizumab in plasma samples from patients with NSCLC and its implications in therapeutic drug monitoring

Given the increasing use of bevacizumab in combinatorial drug therapy for a multitude of different cancer types, there is a need for therapeutic drug monitoring to analyze the possible correlation between drug trough concentration, and therapeutic effect and adverse reactions. An ultra-performance liquid chromatography tandem-mass spectrometry method was then developed and validated to determine bevacizumab levels in human plasma samples. Chromatographic separation was achieved on a Shimadzu InertSustainBio C18 HP column, whereas subsequent mass spectrometric analysis was performed using a Shimadzu 8050CL triple quadrupole mass spectrometer equipped with an electro-spray ionization source in the positive ion mode. In total, three multiple reaction monitoring transitions of each of the surrogate peptides were chosen with 'FTFSLDTSK' applied as the quantification peptide whereas 'VLIYFTSSLHSGVPSR' and 'STAYLQMNSLR' were designated as the verification peptides using the Skyline software. This analytical method was then fully validated, with specificity, linearity, lower limit of quantitation, accuracy, precision, stability, matrix effect and recovery calculated. The linearity of this method was developed to be within the concentration range 5-400 µg/ml for bevacizumab in human plasma. Subsequently, eight patients with non-small cell lung cancer (NSCLC) were recruited and injected with bevacizumab over three periods of treatment to analyze their steady-state trough concentration and differences. To conclude, the results of the present study suggest that bevacizumab can be monitored in a therapeutic setting in patients with NSCLC.

Host cell protein networks as a novel co-elution mechanism during protein A chromatography

Host cell proteins (HCPs) are process-related impurities of therapeutic proteins produced in for example, Chinese hamster ovary (CHO) cells. Protein A affinity chromatography is the initial capture step to purify monoclonal antibodies or Fc-based proteins and is most effective for HCP removal. Previously proposed mechanisms that contribute to co-purification of HCPs with the therapeutic protein are either HCP-drug association or leaching from chromatin heteroaggregates. In this study, we analyzed protein A eluates of 23 Fc-based proteins by LC-MS/MS to determine their HCP content. The analysis revealed a high degree of heterogeneity in the number of HCPs identified in the different protein A eluates. Among all identified HCPs, the majority co-eluted with less than three Fc-based proteins indicating a drug-specific co-purification for most HCPs. Only ten HCPs co-purified with over 50% of the 23 Fc-based proteins. A correlation analysis of HCPs identified across multiple protein A eluates revealed their co-elution as HCP groups. Functional annotation and protein interaction analysis confirmed that some HCP groups are associated with protein-protein interaction networks. Here, we propose an additional mechanism for HCP co-elution involving protein-protein interactions within functional networks. Our findings may help to guide cell line development and to refine downstream purification strategies.

Eculizumab dose tapering should take into account the nonlinearity of its pharmacokinetics

AIMS

Eculizumab is a monoclonal antibody targeting complement protein C5 used in renal diseases. As recommended dosing regimen leads to unnecessarily high concentrations in some patients, tailored dosing therapeutic drug monitoring was proposed to reduce treatment cost. The objectives of the present work were (i) to investigate the target-mediated elimination of eculizumab and (ii) whether a pharmacokinetic model integrating a nonlinear elimination allows a better prediction of eculizumab concentrations than a linear model.

METHODS

We analysed 377 eculizumab serum concentrations from 44 patients treated for atypical haemolytic uraemic syndrome and C3 glomerulopathy with a population pharmacokinetic approach. Critical concentrations (below which a non-log-linear decline of concentration over time is evidenced) were computed to estimate the relevance of the target-mediated elimination. Simulations of dosing regimens were then performed to predict probabilities of target attainment (i.e. trough >100 mg/L).

RESULTS

Pharmacokinetics of eculizumab was nonlinear and followed a mixture of first-order (CL = 1.318 mL/day/kg) and Michaelis-Menten elimination (Vmax = 26.07 mg/day, Km = 24.06 mg/L). Volume of distribution (72.39 mL/kg) and clearance were weight-dependent. Critical concentrations (Vmax/CL) ranged from 144.7 to 759.7 mg/L and were inversely related to body weight (P = .013). Nonlinearity was thus noticeable at therapeutic concentrations. Simulations predicted that 1200 mg of eculizumab every 21 days would allow 85% and 76% of patients to maintain a therapeutic exposure, for 50 or 90 kg body weight, respectively.

CONCLUSIONS

Our study investigates the nonlinear elimination of eculizumab and discusses the importance of accounting for eculizumab target-mediated elimination in therapeutic drug monitoring.

Current progress towards prevention of Nipah and Hendra disease in humans: A scoping review of vaccine and monoclonal antibody candidates being evaluated in clinical trials

OBJECTIVES

Nipah and Hendra are deadly zoonotic diseases with pandemic potential. To date, no human vaccine or monoclonal antibody (mAb) has been licensed to prevent disease caused by these pathogens. The aim of this scoping review was to identify and describe all Phase I, II, and III clinical trials of vaccine candidates or mAbs candidates designed to prevent Nipah and Hendra in humans and to compare the characteristics of the vaccine candidates to characteristics outlined in the Target Product Profile drafted by the World Health Organisation as part of the WHO Research & Development Blueprint for Action to Prevent Epidemics.

METHODS

We searched 23 clinical trial registries, the Cochrane Central Register of Clinical Trials, and grey literature up to June 2023 to identify vaccine and mAb candidates being evaluated in registered clinical trials. Vaccine candidate and trial characteristics were double-extracted for evaluation and the vaccine candidate characteristics were compared with the preferred and critical criteria of the World Health Organisation's Target Product Profile for Nipah virus vaccine.

RESULTS

Three vaccine candidates (Hendra Virus Soluble Glycoprotein Vaccine [HeV-sG-V], PHV02, and mRNA-1215) and one mAb (m102.4) had a registered human clinical trial by June 2023. All trials were phase 1, dose-ranging trials taking place in the United States of America or Australia and enrolling healthy adults. Although all vaccine candidates meet the dose regimen and route of administration criteria of the Target Product Profile, other criteria such as measures of efficacy and reactogenicity will need to be evaluated in the future as evidence becomes available.

CONCLUSION

Multiple vaccine candidates and one mAb candidate have reached the stage of human clinical trials and are reviewed here. Monitoring progress during evaluation of these candidates and candidates entering clinical trials in the future can help highlight many of the challenges that remain.

Safety and biologic activity of a canine anti-CD20 monoclonal antibody in dogs with diffuse large B-cell lymphoma

BACKGROUND

To explore the safety and utility of combining low dose single-agent doxorubicin with a canine specific anti-CD20 monoclonal antibody (1E4-cIgGB) in client owned dogs with untreated B-cell lymphoma.

ANIMALS

Forty-two client-owned dogs with untreated B-cell lymphoma.

METHODS

A prospective, single arm, open label clinical trial of dogs with B-cell lymphoma were enrolled to receive 1E4-cIgGB and doxorubicin in addition to 1 of 3 immunomodulatory regimens. B-cell depletion was monitored by flow cytometry performed on peripheral blood samples at each visit.

RESULTS

Dogs demonstrated a statistically significant depletion in CD21+ B-cells 7 days following the first antibody infusion (median fraction of baseline at 7 days = 0.04, P < .01) that persisted throughout treatment (median fraction of baseline at 21 days = 0.01, P < .01) whereas CD5+ T-cells remained unchanged (median fraction of baseline at 7 days = 1.05, P = .88; median fraction of baselie at 7 days = 0.79, P = .42; Figure 1; Supplemental Table 3). Recovery of B-cells was delayed, with at Day 196, only 6/17 dogs (35%) remaining on the study had CD21+ counts >0.5 of baseline, indicating sustained B cell depletion at 4+ months after the final treatment. 1E4-cIgGB was well tolerated with only 1 dog exhibiting a hypersensitivity event within minutes of the last antibody infusion.

CONCLUSIONS

The canine 1E4-cIgGB anti-CD20 monoclonal antibody is apparently safe when administered with doxorubicin and effectively depletes B-cells in dogs with DLBCL.

Quantum dot-based fluorescence-linked immunosorbent assay for the rapid detection of lomefloxacin in animal-derived foods

Lomefloxacin (LMF), a third-generation fluoroquinolone antibacterial agent, is often used to treat bacterial and mycoplasma infections. However, due to its prolonged half-life and slow metabolism, it is prone to residues in animal-derived foods, posing a potential food safety risk. Therefore, it is particularly urgent and important to establish a method for detecting lomefloxacin. In this study, direct and indirect competitive fluorescence-linked immunosorbent assay (dc-FLISA and ic-FLISA) based on quantum dots (QDs) was established for the detection of LMF. As for dc-FLISA, the half-maximal inhibitory concentration (IC50) and limit of detection (LOD) were 0.84 ng/mL, 0.04 ng/mL, respectively, the detection ranges from 0.08 to 9.11 ng/mL. The IC50 and LOD of ic-FLISA were 0.43 ng/mL and 0.03 ng/mL, respectively, meanwhile the detection ranges from 0.05 to 3.49 ng/mL. The recoveries of dc-FLISA and ic-FLISA in animal-derived foods (milk, fish, chicken, and honey), ranged from 95.8% to 105.2% and from 96.3% to 103.4%, respectively, with the coefficients of variation less than 8%. These results suggest that the dc-FLISA and ic-FLISA methods, which are based on QD labelling, are highly sensitive and cost-effective, and can be effectively used to detect LMF in animal-derived foods.

IMpower210: A phase III study of second-line atezolizumab vs. docetaxel in East Asian patients with non-small cell lung cancer

Objective

IMpower210 (NCT02813785) explored the efficacy and safety of single-agent atezolizumab vs. docetaxel as second-line treatment for advanced non-small cell lung cancer (NSCLC) in East Asian patients.

Methods

Key eligibility criteria for this phase III, open-label, randomized study included age ≥18 years; histologically documented advanced NSCLC per the Union for International Cancer Control/American Joint Committee on Cancer staging system (7th edition); Eastern Cooperative Oncology Group performance status of 0 or 1; and disease progression following platinum-based chemotherapy for advanced or metastatic NSCLC. Patients were randomized 2:1 to receive either atezolizumab (1,200 mg) or docetaxel (75 mg/m2). The primary study endpoint was overall survival (OS) in the intention-to-treat (ITT) population with wild-type epidermal growth factor receptor expression (ITT EGFR-WT) and in the overall ITT population.

Results

Median OS in the ITT EGFR-WT population (n=467) was 12.3 [95% confidence interval (95% CI), 10.3-13.8] months in the atezolizumab arm (n=312) and 9.9 (95% CI, 7.8-13.9) months in the docetaxel arm [n=155; stratified hazard ratio (HR), 0.82; 95% CI, 0.66-1.03]. Median OS in the overall ITT population was 12.5 (95% CI, 10.8-13.8) months with atezolizumab treatment and 11.1 (95% CI, 8.4-14.2) months (n=377) with docetaxel treatment (n=188; stratified HR, 0.87; 95% CI, 0.71-1.08). Grade 3/4 treatment-related adverse events (TRAEs) occurred in 18.4% of patients in the atezolizumab arm and 50.0% of patients in the docetaxel arm.

Conclusions

IMpower210 did not meet its primary efficacy endpoint of OS in the ITT EGFR-WT or overall ITT populations. Atezolizumab was comparatively more tolerable than docetaxel, with a lower incidence of grade 3/4 TRAEs.

Sensing antibody functions with a novel CCR8-responsive engineered cell

Human chemokine receptor 8 (CCR8) is a promising drug target for immunotherapy of cancer and autoimmune diseases. Monoclonal antibody-based CCR8 targeted treatment shows significant inhibition in tumor growth. The inhibition of CCR8 results in the improvement of antitumor immunity and patient survival rates by regulating tumor-resident regulatory T cells. Recently monoclonal antibody drug development targeting CCR8 has become a research hotspot, which also promotes the advancement of antibody evaluation methods. Therefore, we constructed a novel engineered customized cell line HEK293-cAMP-biosensor-CCR8 combined with CCR8 and a cAMP-biosensor reporter. It can be used for the detection of anti-CCR8 antibody functions like specificity and biological activity, in addition to the detection of antibody-dependent cell-mediated cytotoxicity and antibody-dependent-cellular-phagocytosis. We obtained a new CCR8 mAb 22H9 and successfully verified its biological activities with HEK293-cAMP-biosensor-CCR8. Our reporter cell line has high sensitivity and specificity, and also offers a rapid kinetic detection platform for evaluating anti-CCR8 antibody functions.

Development of an effective single-chain variable fragment recognizing a novel epitope in the hepatitis C virus E2 protein that restricts virus entry into hepatocytes

Previously, we reported a neutralizing monoclonal antibody, A8A11, raised against a novel conserved epitope within the hepatitis C virus (HCV) E2 protein, that could significantly reduce HCV replication. Here, we report the nucleotide sequence of A8A11 and demonstrate the efficacy of a single-chain variable fragment (scFv) protein that mimics the antibody, inhibits the binding of an HCV virus-like particle to hepatocytes, and reduces viral RNA replication in a cell culture system. More importantly, scFv A8A11 was found to effectively restrict the increase of viral RNA levels in the serum of HCV-infected chimeric mice harbouring human hepatocytes. These results suggest a promising approach to neutralizing-antibody-based therapeutic interventions against HCV infection.

Vaccines and monoclonal antibodies: new tools for malaria control

SUMMARYMalaria remains one of the biggest health problems in the world. While significant reductions in malaria morbidity and mortality had been achieved from 2000 to 2015, the favorable trend has stalled, rather significant increases in malaria cases are seen in multiple areas. In 2022, there were 249 million estimated cases, and 608,000 malaria-related deaths, mostly in infants and children aged under 5 years, globally. Therefore, in addition to the expansion of existing anti-malarial control measures, it is critical to develop new tools, such as vaccines and monoclonal antibodies (mAbs), to fight malaria. In the last 2 years, the first and second malaria vaccines, both targeting Plasmodium falciparum circumsporozoite proteins (PfCSP), have been recommended by the World Health Organization to prevent P. falciparum malaria in children living in moderate to high transmission areas. While the approval of the two malaria vaccines is a considerable milestone in vaccine development, they have much room for improvement in efficacy and durability. In addition to the two approved vaccines, recent clinical trials with mAbs against PfCSP, blood-stage vaccines against P. falciparum or P. vivax, and transmission-blocking vaccine or mAb against P. falciparum have shown promising results. This review summarizes the development of the anti-PfCSP vaccines and mAbs, and recent topics in the blood- and transmission-blocking-stage vaccine candidates and mAbs. We further discuss issues of the current vaccines and the directions for the development of next-generation vaccines.

Current status of drugs targeting PDGF/PDGFR

As an important proangiogenic factor, platelet-derived growth factor (PDGF) and its receptor PDGFR are highly expressed in a variety of tumors, fibrosis, cardiovascular and neurodegenerative diseases. Targeting the PDGF/PDGFR pathway is therefore a promising therapeutic strategy. At present, a variety of PDGF/PDGFR targeted drugs with potential therapeutic effects have been developed, mainly including PDGF agonists, inhibitors targeting PDGFR and proteolysis targeting chimera (PROTACs). This review clarifies the structure, biological function and disease correlation of PDGF and PDGFR, and it discusses the current status of PDGFR-targeted drugs, so as to provide a reference for subsequent research.

Investigation on the Combined Effect of Hydroxypropyl Beta-Cyclodextrin (HPβCD) and Polysorbate in Monoclonal Antibody Formulation

Monoclonal antibodies require careful formulation due to their inherent stability limitations. Polysorbates are commonly used to stabilize mAbs, but they are prone to degradation, which results in unwanted impurities. KLEPTOSE® HPβCD (hydroxypropyl beta-cyclodextrin) has functioned as a stable stabilizer for protein formulations in our previous research. The current study investigates the collaborative impact of combining polysorbates and HPβCD as excipients in protein formulations. The introduction of HPβCD in formulations showed it considerably reduced aggregation in two model proteins, bevacizumab and ipilimumab, following exposure to various stress conditions. The diffusion interaction parameter revealed a reduction in protein-protein interactions by HPβCD. In bevacizumab formulations, the subvisible particle counts per 0.4 mL of samples in commercial formulations vs. formulations containing both HPβCD and polysorbates subjected to distinct stressors were as follows: agitation, 87,308 particles vs. 15,350 particles; light, 25,492 particles vs. 6765 particles; and heat, 1775 particles vs. 460 particles. Isothermal titration calorimetry (ITC) measurement indicated a weak interaction between PS 80 and HPβCD, with a KD value of 74.7 ± 7.5 µM and binding sites of 5 × 10-3. Surface tension measurements illustrated that HPβCD enhanced the surface activity of polysorbates. The study suggests that combining these excipients can improve mAb stability in formulations, offering an alternative for the biopharmaceutical industry.

A Lateral-Flow Device for the Rapid Detection of Scedosporium Species

Scedosporium species are human pathogenic fungi, responsible for chronic, localised, and life-threatening disseminated infections in both immunocompetent and immunocompromised individuals. The diagnosis of Scedosporium infections currently relies on non-specific CT, lengthy and insensitive culture from invasive biopsy, and the time-consuming histopathology of tissue samples. At present, there are no rapid antigen tests that detect Scedosporium-specific biomarkers. Here, we report the development of a rapid (30 min) and sensitive (pmol/L sensitivity) lateral-flow device (LFD) test, incorporating a Scedosporium-specific IgG1 monoclonal antibody (mAb), HG12, which binds to extracellular polysaccharide (EPS) antigens between ~15 kDa and 250 kDa secreted during the hyphal growth of the pathogens. The test is compatible with human serum and allows for the detection of the Scedosporium species most frequently reported as agents of human disease (Scedosporium apiospermum, Scedosporium aurantiacum, and Scedosporium boydii), with limits of detection (LODs) of the EPS biomarkers in human serum of ~0.81 ng/mL (S. apiospermum), ~0.94 ng/mL (S. aurantiacum), and ~1.95 ng/mL (S. boydii). The Scedosporium-specific LFD (ScedLFD) test therefore provides a potential novel opportunity for the detection of infections caused by different Scedosporium species.

Emerging monoclonal antibody therapy for head and neck squamous cell carcinoma

INTRODUCTION

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing, particularly among younger populations. It is projected that the number of new cases will increase by almost 50% by 2040, with market revenues expected to triple in the same period. Despite the recent introduction of immune checkpoint inhibitors (ICIs) into the therapeutic armamentarium, the vast majority of patients with recurrent and/or metastatic (R/M) HNSCC fail to derive durable benefits from systemic therapy.

AREAS COVERED

This article aims to review the multiple monoclonal antibodies (mAbs) regimens currently under development, targeting various growth factors, immune checkpoints, immune costimulatory receptors, and more.

EXPERT OPINION

So far, the combination of anti-EGFR and ICI appears to be the most promising, especially in HPV-negative patients. It will be interesting to confirm whether the arrival of antibody-drug conjugates and bispecific mAb can surpass the efficacy of anti-EGFR, as they are also being tested in combination with ICI. Furthermore, we believe that immune costimulatory agonists and various ICIs combination are worth monitoring, despite some initial setbacks.

Therapeutic Drug Monitoring as a Tool for the Clinical Outcome Prediction in Vedolizumab-Treated Patients: An Italian Pilot Study

Over the years, vedolizumab (VDZ) has emerged as a more effective target therapy for inflammatory bowel disease. The aim of this work was to analyze a cohort of inflammatory bowel disease patients, evaluating the association between VDZ serum concentrations at 6 months from starting therapy and their clinical and biochemical indexes within one year of treatment, correlating drug levels with response and clinical remission. Forty patients treated with VDZ were enrolled. Drug concentrations were quantified through ELISA methods. VDZ levels correlated with hemoglobin levels at twelve months of therapy (p = 0.03) and with clinical remission at twelve months of therapy (p = 0.03); patients who reached clinical remission showed higher VDZ concentrations. A VDZ cut-off value of 43.1 μg/mL was suggested, predicting clinical remission at twelve months of therapy. A statistically significant association between VDZ levels at T6 and calprotectin <250 μg/g at T12 was found (p = 0.04). Furthermore, the optimal threshold value of VDZ levels at T6 associated with calprotectin <250 μg/g at T12 was identified: through levels higher than 45.2 µg/mL, we were able to predict remission one year after therapy. In the final regression multivariate model, no factor was retained as a predictor of clinical remission at one year of treatment. In conclusion, this is the first pilot study reporting a possible VDZ serum cut-off value able to predict not only the clinical remission at twelve months of therapy but also the calprotectin level, which is very important, as it is a surrogate marker of mucosal healing.

Development of a Monoclonal Antibody-Based Indirect Competitive Enzyme-Linked Immunosorbent Assay for the Rapid Detection of Gallic Acid

Gallic acid (GA) is closely related to the quality of herbal medicines and other agricultural products. In order to facilitate the rapid detection of GA, we developed a monoclonal antibody-based ic-ELISA method. Antigens with and without connecting arms were prepared. It was found that the introduction of connecting arms (linear carbon chain) was beneficial for immune response. By utilizing hybridoma technology, a specific mAb (anti-GA-M702) was screened and identified, which exhibited a 1:40,500 antibody titer and IgG2b antibody subtype. The ic-ELISA assay was established based on anti-GA-M702. The optimal working concentrations of the encapsulated antigen and antibody were 0.5 µg/mL and 0.67 µg/mL, respectively. The ic-ELISA method showed a linear detection range of 297.17-2426.61 ng/mL for GA with a sensitivity of 849.18 ng/mL. It displayed a good applicability for the determination of GA in Galla chinensis. In conclusion, the ic-ELISA method provides an efficient approach to the rapid detection of GA in products.

Direct Injection Electrospray Ionization Mass Spectrometry (ESI-MS) Analysis of Proteins with High Matrix Content:Utilizing Taylor-Aris Dispersion

This is the first work demonstrating the utility of the Taylor-Aris (TA) dispersion in avoiding serious interference issues commonly occurring in the electrospray ionization-mass spectrometric (ESI-MS) determination of therapeutic protein pharmaceuticals undergoing no pre-separation or sample purification. It was also pointed out that the TA dispersion conditions and its analytical utilization for proteomics can be easily accomplished in a commercial CE-MS instrument. In the proposed Taylor-Aris dispersion-assisted mass spectrometry (TADA-MS) analysis 0.5 μL sample is injected into a 65 cm long 50 μm i.d. capillary and pumped with 1 bar toward the MS. The procedure is efficient for the direct injection analysis of components having low diffusion coefficients (proteins) that are present in complex matrices of small organic and inorganic compounds.

Advancements in cancer immunotherapies targeting CD20: from pioneering monoclonal antibodies to chimeric antigen receptor-modified T cells

CD20 located predominantly on the B cells plays a crucial role in their development, differentiation, and activation, and serves as a key therapeutic target for the treatment of B-cell malignancies. The breakthrough of monoclonal antibodies directed against CD20, notably exemplified by rituximab, revolutionized the prognosis of B-cell malignancies. Rituximab, approved across various hematological malignancies, marked a paradigm shift in cancer treatment. In the current landscape, immunotherapies targeting CD20 continue to evolve rapidly. Beyond traditional mAbs, advancements include antibody-drug conjugates (ADCs), bispecific antibodies (BsAbs), and chimeric antigen receptor-modified (CAR) T cells. ADCs combine the precision of antibodies with the cytotoxic potential of drugs, presenting a promising avenue for enhanced therapeutic efficacy. BsAbs, particularly CD20xCD3 constructs, redirect cytotoxic T cells to eliminate cancer cells, thereby enhancing both precision and potency in their therapeutic action. CAR-T cells stand as a promising strategy for combatting hematological malignancies, representing one of the truly personalized therapeutic interventions. Many new therapies are currently being evaluated in clinical trials. This review serves as a comprehensive summary of CD20-targeted therapies, highlighting the progress and challenges that persist. Despite significant advancements, adverse events associated with these therapies and the development of resistance remain critical issues. Understanding and mitigating these challenges is paramount for the continued success of CD20-targeted immunotherapies.

Characterization of a neutralizing antibody that recognizes a loop region adjacent to the receptor-binding interface of the SARS-CoV-2 spike receptor-binding domain

Although the global crisis caused by the coronavirus disease 2019 (COVID-19) pandemic is over, the global epidemic of the disease continues. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of COVID-19, initiates infection via the binding of the receptor-binding domain (RBD) of its spike protein to the human angiotensin-converting enzyme II (ACE2) receptor, and this interaction has been the primary target for the development of COVID-19 therapeutics. Here, we identified neutralizing antibodies against SARS-CoV-2 by screening mouse monoclonal antibodies and characterized an antibody, CSW1-1805, that targets a narrow region at the RBD ridge of the spike protein. CSW1-1805 neutralized several variants in vitro and completely protected mice from SARS-CoV-2 infection. Cryo-EM and biochemical analyses revealed that this antibody recognizes the loop region adjacent to the ACE2-binding interface with the RBD in both a receptor-inaccessible "down" state and a receptor-accessible "up" state and could stabilize the RBD conformation in the up-state. CSW1-1805 also showed different binding orientations and complementarity determining region properties compared to other RBD ridge-targeting antibodies with similar binding epitopes. It is important to continuously characterize neutralizing antibodies to address new variants that continue to emerge. Our characterization of this antibody that recognizes the RBD ridge of the spike protein will aid in the development of future neutralizing antibodies.IMPORTANCESARS-CoV-2 cell entry is initiated by the interaction of the viral spike protein with the host cell receptor. Therefore, mechanistic findings regarding receptor recognition by the spike protein help uncover the molecular mechanism of SARS-CoV-2 infection and guide neutralizing antibody development. Here, we characterized a SARS-CoV-2 neutralizing antibody that recognizes an epitope, a loop region adjacent to the receptor-binding interface, that may be involved in the conformational transition of the receptor-binding domain (RBD) of the spike protein from a receptor-inaccessible "down" state into a receptor-accessible "up" state, and also stabilizes the RBD in the up-state. Our mechanistic findings provide new insights into SARS-CoV-2 receptor recognition and guidance for neutralizing antibody development.

Comprehensive performance evaluation of ligand-binding assay-LC-MS/MS method for co-dosed monoclonal anti-SARS-CoV-2 antibodies (AZD7442)

Aims: AZD7442 is a combination SARS-CoV-2 therapy comprising two co-dosed monoclonal antibodies. Materials & methods: The authors validated a hybrid ligand-binding assay-LC-MS/MS method for pharmacokinetic assessment of AZD7442 in human serum with nominal concentration range of each analyte of 0.300-30.0 μg/ml. Results: Validation results met current regulatory acceptance criteria. The validated method supported three clinical trials that spanned more than 17 months and ≥720 analytical runs (∼30,000 samples and ∼3000 incurred sample reanalyses per analyte). The data generated supported multiple health authority interactions, across the globe. AZD7442 (EVUSHELD) was approved in 12 countries for pre-exposure prophylaxis of COVID-19. Conclusion: The results reported here demonstrate the robust, high-throughput capability of the hybrid ligand-binding assay-LC-MS/MS approach being employed to support-next generation versions of EVUSHELD, AZD3152.

Generation of novel anti-apoE monoclonal antibodies that selectively recognize apoE isoforms

Apolipoprotein E (apoE) is a regulator of lipid metabolism, cholesterol transport, and the clearance and aggregation of amyloid β in the brain. The three human apoE isoforms apoE2, apoE3, and apoE4 only differ in one or two residues. Nevertheless, the functions highly depend on the isoform types and lipidated states. Here, we generated novel anti-apoE monoclonal antibodies (mAbs) and obtained an apoE4-selective mAb whose epitope is within residues 110-117. ELISA and bio-layer interferometry measurements demonstrated that the dissociation constants of mAbs are within the nanomolar range. Using the generated antibodies, we successfully constructed sandwich ELISA systems, which can detect all apoE isoforms or selectively detect apoE4. These results suggest the usability of the generated anti-apoE mAbs for selective detection of apoE isoforms.

Characterization of Two Highly Specific Monoclonal Antibodies Targeting the Glycan Loop of the Zika Virus Envelope Protein

Zika virus (ZIKV) is an emerging flavivirus associated with several neurological diseases such as Guillain-Barré syndrome in adults and microcephaly in newborn children. Its distribution and mode of transmission (via Aedes aegypti and Aedes albopictus mosquitoes) collectively cause ZIKV to be a serious concern for global health. High genetic homology of flaviviruses and shared ecology is a hurdle for accurate detection. Distinguishing infections caused by different viruses based on serological recognition can be misleading as many anti-flavivirus monoclonal antibodies (mAbs) discovered to date are highly cross-reactive, especially those against the envelope (E) protein. To provide more specific research tools, we produced ZIKV E directed hybridoma cell lines and characterized two highly ZIKV-specific mAb clones (mAbs A11 and A42) against several members of the Flavivirus genus. Epitope mapping of mAb A11 revealed glycan loop specificity in Domain I of the ZIKV E protein. The development of two highly specific mAbs targeting the surface fusion protein of ZIKV presents a significant advancement in research capabilities as these can be employed as essential tools to enhance our understanding of ZIKV identification on infected cells ex vivo or in culture.

A High Threshold of Biotherapeutic Aggregate Numbers is Needed to Induce an Immunogenic Response In Vitro, In Vivo, and in the Clinic

BACKGROUND AND PURPOSE

There is concern that subvisible aggregates in biotherapeutic drug products pose a risk to patient safety. We investigated the threshold of biotherapeutic aggregates needed to induce immunogenic responses.

METHODS AND RESULTS

Highly aggregated samples were tested in cell-based assays and induced cellular responses in a manner that depended on the number of particles. The threshold of immune activation varied by disease state (cancer, rheumatoid arthritis, allergy), concomitant therapies, and particle number. Compared to healthy donors, disease state patients showed an equal or lower response at the late phase (7 days), suggesting they may not have a higher risk of responding to aggregates. Xeno-het mice were used to assess the threshold of immune activation in vivo. Although highly aggregated samples (~ 1,600,000 particles/mL) induced a weak and transient immunogenic response in mice, a 100-fold dilution of this sample (~ 16,000 particles/mL) did not induce immunogenicity. To confirm this result, subvisible particles (up to ~ 18,000 particles/mL, containing aggregates and silicone oil droplets) produced under representative administration practices (created upon infusion of a drug product through an IV catheter) did not induce a response in cell-based assays or appear to increase the rate of adverse events or immunogenicity during phase 3 clinical trials.

CONCLUSION

The ability of biotherapeutic aggregates to elicit an immune response in vitro, in vivo, and in the clinic depends on high numbers of particles. This suggests that there is a high threshold for aggregates to induce an immunogenic response which is well beyond that seen in standard biotherapeutic drug products.

Epitope Mapping of an Anti-Mouse CD39 Monoclonal Antibody Using PA Scanning and RIEDL Scanning

A cell-surface ectonucleotidase CD39 mediates the conversion of extracellular adenosine triphosphate into immunosuppressive adenosine with another ectonucleotidase CD73. The elevated adenosine in the tumor microenvironment attenuates antitumor immunity, which promotes tumor cell immunologic escape and progression. Anti-CD39 monoclonal antibodies (mAbs), which suppress the enzymatic activity, can be applied to antitumor therapy. Therefore, an understanding of the relationship between the inhibitory activity and epitope of mAbs is important. We previously established an anti-mouse CD39 (anti-mCD39) mAb, C39Mab-1 using the Cell-Based Immunization and Screening method. In this study, we determined the critical epitope of C39Mab-1 using flow cytometry. We performed the PA tag (12 amino acids [aa])-substituted analysis (named PA scanning) and RIEDL tag (5 aa)-substituted analysis (named RIEDL scanning) to determine the critical epitope of C39Mab-1 using flow cytometry. By the combination of PA scanning and RIEDL scanning, we identified the conformational epitope, spanning three segments of 275-279, 282-291, and 306-323 aa of mCD39. These analyses would contribute to the identification of the conformational epitope of membrane proteins.

Identification of Surfactant Impact on a Monoclonal Antibody Characterization via HPLC-Separation Based and Biophysical Methods

PURPOSE OR OBJECTIVE

Surfactants, including polysorbates and poloxamers, play a crucial role in the formulation of therapeutic proteins by acting as solubilizing and stabilizing agents. They help prevent protein aggregation and adsorption, thereby enhancing the stability of drug substance and products., However, it is important to note that utilizing high concentrations of surfactants in protein formulations can present significant analytical challenges, which can ultimately affect the product characterization.

METHODS

In our study, we specifically investigated the impact of elevated surfactant concentrations on the characterization of monoclonal antibodies. We employed various analytical techniques including size-exclusion chromatography (SEC), capillary electrophoresis (CE-SDS), a cell based functional assay, and biophysical characterization.

RESULTS

The findings of our study indicate that higher levels of Polysorbate 80 (PS-80) have adverse effects on the measured purity, biological activity, and biophysical characterization of biologic samples. Specifically, the elevated levels of PS-80 cause analytical interferences, which can significantly impact the accuracy and reliability of analytical studies.

CONCLUSIONS

Our study results highlight a significant risk in analytical investigations, especially in studies involving the isolation and characterization of impurities. It is important to be cautious of surfactant concentrations, as they can become more concentrated during common sample manipulations like buffer exchange. Indeed, the research presented in this work emphasizes the necessity to evaluate the impact on analytical assays when there are substantial alternations in the matrix composition. By doing so, valuable insights can be gained regarding potential challenges associated with assay development and characterization of biologics with complex formulations.

Personalized Cancer Nanomedicine: Overcoming Biological Barriers for Intracellular Delivery of Biopharmaceuticals

The success of personalized medicine in oncology relies on using highly effective and precise therapeutic modalities such as small interfering RNA (siRNA) and monoclonal antibodies (mAbs). Unfortunately, the clinical exploitation of these biological drugs has encountered obstacles in overcoming intricate biological barriers. Drug delivery technologies represent a plausible strategy to overcome such barriers, ultimately facilitating the access to intracellular domains. Here, an overview of the current landscape on how nanotechnology has dealt with protein corona phenomena as a first and determinant biological barrier is presented. This continues with the analysis of strategies facilitating access to the tumor, along with conceivable methods for enhanced tumor penetration. As a final step, the cellular barriers that nanocarriers must confront in order for their biological cargo to reach their target are deeply analyzed. This review concludes with a critical analysis and future perspectives of the translational advances in personalized oncological nanomedicine.

Development and characterisation of highly specific monoclonal antibody-based immunoassays for the detection and quantification of genistein-7-O-[α-rhamnopyranosyl-(1→6)]-β-glucopyranoside in Derris scandens (Roxb.) Benth

INTRODUCTION

The stem of the plant species Derris scandens (Roxb.) Benth. (DS) contains genistein-7-O-[α-rhamnopyranosyl-(1→6)]-β-glucopyranoside (GTG), which is a unique marker. Previous analyses of GTG using antibody-based immunoassays were compromised because of their high cross-reactivity with structurally related compounds of DS, thereby limiting their applicability in DS quality control.

OBJECTIVE

Conjugation of GTG with carrier proteins was achieved using the Mannich reaction to produce a highly specific monoclonal antibody (mAb) targeting GTG (anti-GTG mAb).

METHODS

The anti-GTG mAb was generated using hybridoma technology and characterised using an indirect competitive enzyme-linked immunosorbent assay (icELISA). Both lateral-flow immunoassay (LFIA) and icELISA were developed to detect and quantify GTG in DS raw materials and associated products.

RESULTS

icELISA using the anti-GTG mAb showed 100% specificity for GTG, with only 1.77% cross-reactivity with genistin and less than 0.01% cross-reactivity with other compounds. icELISA demonstrated a linear range for GTG determination between 62.5 and 2000 ng/mL. The limits of detection (LOD) and quantification were 49.68 and 62.50 ng/mL for GTG, respectively. The precision of the analysis ranged from 1.28% to 4.20% for repeatability and from 1.03% to 7.05% for reproducibility. The accuracy of the analysis ranged from 101.97% to 104.01% for GTG recovery. GTG levels determined via icELISA were consistent with those confirmed via high-performance liquid chromatography (HPLC) (R2 = 0.9903). Moreover, the LOD of LFIA for GTG was 500 ng/mL.

CONCLUSION

Immunoassays utilising specific anti-GTG mAbs were successfully developed, including LFIA for rapid GTG detection and icELISA for GTG quantification.

Development of a novel humanized anti-TSLP monoclonal antibody HZ-1127 with anti-allergic diseases and cancer potential

Thymic stromal lymphopoietin (TSLP) is a member of the IL-2 cytokine family and has been widely recognized as a master regulator of type 2 inflammatory responses at barrier surfaces. Recent studies found dysregulation of the TSLP-TSLP receptor (TSLPR) pathway is associated with the pathogenesis of not only allergic diseases but also a wide variety of cancers including both solid tumors and hematological tumors. Thus, the blockade of TSLP represents an attractive therapeutic strategy for allergic diseases and cancer. In this study, we report the development of a novel humanized anti-TSLP monoclonal antibody (mAb) HZ-1127. Binding affinity, specificity, and ability of HZ-1127 in inhibiting TSLP were tested. HZ-1127 selectively binds to the TSLP cytokine with high affinity and specificity. Furthermore, HZ-1127 dramatically inhibits TSLP-dependent STAT5 activation and is more potent than Tezepelumab, which is an FDA-approved humanized mAb against TSLP for severe asthma treatment in inhibiting TSLP-induced CCL17 and CCL22 chemokines secretion in human peripheral blood mononuclear cells. Our pre-clinical study demonstrates that HZ-1127 may serve as a potential therapeutic agent for allergic diseases and cancer.

PMab-314: An Anti-Giant Panda Podoplanin Monoclonal Antibody

The giant panda (Ailuropoda melanoleuca) is one of the important species in worldwide animal conservation. Because it is essential to understand the disease of giant panda for conservation, histopathological analyses of tissues are important to understand the pathogenesis. However, monoclonal antibodies (mAbs) against giant panda-derived proteins are limited. Podoplanin (PDPN) is an essential marker of lung type I alveolar epithelial cells, kidney podocytes, and lymphatic endothelial cells. PDPN is also overexpressed in various human tumors, which are associated with poor prognosis. Here, an anti-giant panda PDPN (gpPDPN) mAb, PMab-314 (mouse IgG1, kappa) was established using the Cell-Based Immunization and Screening method. PMab-314 recognized N-terminal PA16-tagged gpPDPN-overexpressed Chinese hamster ovary-K1 cells (CHO/PA16-gpPDPN) in flow cytometry. The KD value of PMab-314 for CHO/PA16-gpPDPN was determined as 1.3 × 10-8 M. Furthermore, PMab-314 is useful for detecting gpPDPN in western blot analysis. These findings indicate that PMab-314 is a useful tool for the analyses of gpPDPN-expressed cells.

Establishment of a Novel Anti-Mouse CCR1 Monoclonal Antibody C1Mab-6

C-C motif chemokine receptor 1 (CCR1/CD191) is a member of G-protein-coupled receptors and is expressed on myeloid cells, such as neutrophils and macrophages. Because the CCR1 signaling promotes tumor expansion in the tumor microenvironment (TME), the modification of TME is an effective strategy for cancer therapy. Although CCR1 is an attractive target for solid tumors and hematological malignancies, therapeutic agents for CCR1 have not been approved. Here, we established a novel anti-mouse CCR1 (mCCR1) monoclonal antibody (mAb), C1Mab-6 (rat IgG2b, kappa), using the Cell-Based Immunization and Screening method. Flow cytometry and Western blot analyses showed that C1Mab-6 recognizes mCCR1 specifically. The dissociation constant of C1Mab-6 for mCCR1-overexpressed Chinese hamster ovary-K1 was determined as 3.9 × 10-9 M, indicating that C1Mab-6 possesses a high affinity to mCCR1. These results suggest that C1Mab-6 could be a useful tool for targeting mCCR1 in preclinical mouse models.

Development of a unique sandwich enzyme-linked immunosorbent assay based on monoclonal antibodies for the specific detection of the egg drop syndrome virus

RESEARCH HIGHLIGHTS

A sandwich ELISA was developed to detect EDSV using the mAbs 5G4 and HRP-6G6.The sandwich ELISA maintained high specificity and sensitivity.The sandwich ELISA had equivalent consistency with real-time PCR assay.

Selective Uptake of Macromolecules to the Brain in Microfluidics and Animal Models Using the HAVN1 Peptide as a Blood-Brain Barrier Modulator

Monoclonal antibodies (mAbs) possess favorable pharmacokinetic properties, high binding specificity and affinity, and minimal off-target effects, making them promising therapeutic agents for central nervous system (CNS) disorders. However, their development as effective therapeutic and diagnostic agents for brain disorders is hindered by their limited ability to efficiently penetrate the blood-brain barrier (BBB). Therefore, it is crucial to develop efficient delivery methods that enhance the penetration of antibodies into the brain. Previous studies have demonstrated the potential of cadherin-derived peptides (i.e., ADTC5, HAVN1 peptides) as BBB modulators (BBBMs) to increase paracellular porosities for penetration of molecules across the BBB. Here, we test the effectiveness of the leading BBBM peptide, HAVN1 (Cyclo(1,6)SHAVSS), in enhancing the permeation of various monoclonal antibodies through the BBB using both in vitro and in vivo systems. In vitro, HAVN1 has been shown to increase the permeability of fluorescently labeled macromolecules, such as a 70 kDa dextran, 50 kDa Fab1, and 150 kDa mAb1, by 4- to 9-fold in a three-dimensional blood-brain barrier (3D-BBB) microfluidics model using a human BBB endothelial cell line (i.e., hCMEC/D3). HAVN1 was selective in modulating the BBB endothelial cell, compared to the pulmonary vascular endothelial (PVE) cell barrier. Co-administration of HAVN1 significantly improved brain depositions of mAb1, mAb2, and Fab1 in C57BL/6 mice after 15 min in the systemic circulation. Furthermore, HAVN1 still significantly enhanced brain deposition of mAb2 when it was administered 24 h after the administration of the mAb. Lastly, we observed that multiple doses of HAVN1 may have a cumulative effect on the brain deposition of mAb2 within a 24-h period. These findings offer promising insights into optimizing HAVN1 and mAb dosing regimens to control or modulate mAb brain deposition for achieving desired mAb dose in the brain to provide its therapeutic effects.

Factors affecting product association as a mechanism of host-cell protein persistence in bioprocessing

Product association of host-cell proteins (HCPs) to monoclonal antibodies (mAbs) is widely regarded as a mechanism that can enable HCP persistence through multiple purification steps and even into the final drug substance. Discussion of this mechanism often implies that the existence or extent of persistence is directly related to the strength of binding but actual measurements of the binding affinity of such interactions remain sparse. Two separate avenues of investigation of HCP-mAb binding are reported here. One is the measurement of the affinity of binding of individual, commonly persistent Chinese hamster ovary (CHO) HCPs to each of a set of mAbs, and the other uses quantitative proteomic measurements to assess binding of HCPs in a null CHO harvested cell culture fluid (HCCF) to mAbs produced in the same cell line. The individual HCP measurements show that the binding affinities of individual HCPs to different mAbs can vary appreciably but are rarely very high, with only weak pH dependence. The measurements on the null HCCF allow estimation of individual HCP-mAb affinities; these are typically weaker than those seen in affinity measurements on isolated HCPs. Instead, the extent of binding appears correlated with the initial abundance of individual HCPs in the HCCF and the forms of the HCPs in the solution, i.e., whether HCPs are present as free molecules or as parts of large aggregates. Separate protein A chromatography experiments performed by feeding different fractions of a mAb-containing HCCF obtained by size-exclusion chromatography (SEC) showed clear differences in the number and identity of HCPs found in the protein A eluate. These results indicate a significant role for HCP-mAb association in determining HCP persistence through protein A chromatography, presumably through binding of HCP-mAb complexes to the resin. Overall, the results illustrate the importance of considering more fully the biophysical context of HCP-product association in assessing the factors that may affect the phenomenon and determine its implications. Knowledge of the abundances and the forms of individual or aggregated HCPs in HCCF are particularly significant, emphasizing the integration of upstream and downstream bioprocessing and the importance of understanding the collective properties of HCPs in addition to just the biophysical properties of individual HCPs.

In vivo evaluation of monoclonal antibody M4M using a humanised rat model of stroke demonstrates attenuation of reperfusion injury via blocking human TRPM4 channel

BACKGROUND

Blocking Transient Receptor Potential Melastatin 4 (TRPM4) in rodents by our antibody M4P has shown to attenuate cerebral ischaemia-reperfusion injury. Since M4P does not interact with human TRPM4, the therapeutic potential of blocking human TRPM4 remains unclear. We developed a monoclonal antibody M4M that inhibited human TRPM4 in cultured cells. However, M4M has no effect on stroke outcome in wild-type rats. Therefore, M4M needs to be evaluated on animal models expressing human TRPM4.

METHODS

We generated a humanised rat model using the CRISPR/Cas technique to knock-in (KI) the human TRPM4 antigen sequence.

RESULTS

In primary neurons from human TRPM4 KI rats, M4M binds to hypoxic neurons, but not normoxic nor wild-type neurons. Electrophysiological studies showed that M4M blocked ATP depletion-induced activation of TRPM4 and inhibited hypoxia-associated cell volume increase. In a stroke model, administration of M4M reduced infarct volume in KI rats. Rotarod test and Neurological deficit score revealed improvement following M4M treatment.

CONCLUSION

M4M selectively binds and inhibits hypoxia-induced human TRPM4 channel activation in neurons from the humanised rat model, with no effect on healthy neurons. Use of M4M in stroke rats showed functional improvements, suggesting the potential for anti-human TRPM4 antibodies in treating acute ischaemic stroke patients.

Cx1Mab-1: A Novel Anti-mouse CXCR1 Monoclonal Antibody for Flow Cytometry

The C-X-C motif chemokine receptor-1 (CXCR1) is a rhodopsin-like G-protein-coupled receptor, expressed on the cell surface of immune cells and tumors. CXCR1 interacts with some C-X-C chemokines, such as CXCL6, CXCL7, and CXCL8/interleukin-8, which are produced by various cells. Since CXCR1 is involved in several diseases including tumors and diabetes mellitus, drugs targeting CXCR1 have been developed. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CXCR1 has been desired for the diagnosis and treatment. This study established a novel anti-mouse CXCR1 (mCXCR1) mAb, Cx1Mab-1 (rat IgG1, kappa), using the Cell-Based Immunization and Screening method. Cx1Mab-1 reacted with mCXCR1-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR1) and mCXCR1-overexpressed LN229 glioblastoma (LN229/mCXCR1) in flow cytometry. Cx1Mab-1 demonstrated a high binding affinity for CHO/mCXCR1 and LN229/mCXCR1 with a dissociation constant of 2.6 × 10-9 M and 2.1 × 10-8 M, respectively. Furthermore, Cx1Mab-1 could detect mCXCR1 by Western blot analysis. These results indicated that Cx1Mab-1 is useful for detecting mCXCR1, and provides a possibility for targeting mCXCR1-expressing cells in vivo experiments.