Development of a novel sandwich immunoassay based on targeting recombinant Francisella outer membrane protein A for the diagnosis of tularemia.

Introduction: Tularemia, caused by the bacterium Francisella tularensis, poses health risks to humans and can spread through a variety of routes. It has also been classified as a Tier 1 Select agent by the CDC, highlighting its potential as a bioterrorism agent. Moreover, it is difficult to diagnose in a timely fashion, owing to the non-specific nature of tularemia infections. Rapid, sensitive, and accurate detection methods are required to reduce mortality rates. We aimed to develop antibodies directed against the outer membrane protein A of F. tularensis (FopA) for rapid and accurate diagnosis of tularemia. Methods: We used a baculovirus insect cell expression vector system to produce the FopA antigen and generate anti-FopA antibodies through immunization of BALB/c mice. We then employed hybridoma and phage display technologies to screen for antibodies that could recognize unique epitopes on FopA. Result: Two monoclonal antibodies, 6B12 and 3C1, identified through phage display screening specifically bound to recombinant FopA in a dose-dependent manner. The binding affinity of the anti-FopA 6B12 and 3C1 antibodies was observed to have an equilibrium dissociation constant of 1.76 × 10-10 M and 1.32 × 10-9 M, respectively. These antibodies were used to develop a sandwich ELISA system for the diagnosis of tularemia. This assay was found to be highly specific and sensitive, with detection limits ranging from 0.062 ng/mL in PBS to 0.064 ng/mL in skim milk matrices. Discussion: Our findings demonstrate the feasibility of a novel diagnostic approach for detecting F. tularensis based on targeting FopA, as opposed to existing tests that target the bacterial lipopolysaccharide.

Efficacy of daratumumab on multiple myeloma patients with renal insufficiency: a systematic review and meta-analysis.

BACKGROUND: Renal insufficiency (RI) is a key factor affecting the prognosis of multiple myeloma (MM) patients. Because the benefit of daratumumab for treating MM patients with RI remains unclear, our objective was to evaluate the efficacy of daratumumab on MM patients with RI. METHODS: We conducted a systematic search of the PubMed, EMBASE, and Cochrane Library databases as of October 24, 2023. Two independent reviewers screened the article titles, abstracts, and full text to identify the randomized controlled trials (RCTs) meeting the inclusion and exclusion criteria. Meta-analyses were performed using RevMan version 5.4. Outcomes of interest were progression-free survival (PFS), overall survival (OS), complete response or better (≥CR), and minimal residual disease (MRD) negativity, all calculated as hazard ratios (HRs) or risk ratios (RRs) with 95% confidence intervals (CIs). RESULTS: A total of 10 RCTs with 5003 patients were included. Add-on daratumumab improved PFS and OS among newly diagnosed MM (NDMM) patients with RI (HR 0.48 [95% CI: 0.36, 0.64, I2 = 65%] and HR 0.63 [95% CI: 0.48, 0.82, I2 = 0%]) as well as relapsed/refractory MM (RRMM)-RI patients, compared with the control group (HR 0.46 [95% CI: 0.37, 0.58, I2 = 0%] and HR 0.68 [95% CI: 0.51, 0.92, I2 = 0%]). In terms of the renal status, the efficacy of add-on daratumumab for MMRI patients was similar to that for MM patients with normal renal function. A prolonged PFS benefit for add-on daratumumab treatment versus the control was evident across all RRMM-RI subgroups, and the benefits tended to increase with the follow-up time. CONCLUSIONS: Our results indicate that MM patients with RI could benefit from a daratumumab-added regimen regardless of MM status. Additional high-quality RCTs are still warranted to confirm our findings.

[Pathogenesis and Treatment of Amyloid-related Imaging Abnormalities Caused by Disease-modifying Drugs in Alzheimer's Disease].

Amyloid-related imaging abnormalities (ARIA) represent the most frequent adverse effect of lecanemab, a monoclonal antibody drug that targets amyloid beta. ARIA is observed in approximately 20% of patients who receive lecanemab. Most patients are asymptomatic; however, some develop serious neurological symptoms, and optimal management remains clinically challenging in such cases. In this review, I summarize the pathomechanism underlying ARIA and associated disorders, in addition to countermeasures for ARIA.

USE OF SOLENSIA (FRUNEVETMAB) IN NONDOMESTIC FELIDS (PANTHERA TIGRIS, LYNX RUFUS, PANTHERA UNCIA) GUIDED BY PROTEIN SEQUENCE ANALYSIS.

Osteoarthritis and degenerative joint disease affect many species of nondomestic felid and negatively impact quality of life in managed care settings. Previously, pain management options were limited because of the frequency of comorbidities such as renal disease and common difficulty encountered in medication administration. SolensiaTM (frunevetmab) is a felinized monoclonal antibody that binds to nerve growth factor in arthritic joints, thereby inhibiting pain response cascades, and produces marked improvement in clinical signs and quality of life in domestic cats diagnosed with osteoarthritis. Protein sequence analysis was performed to inform the application of frunevetmab in four individuals from three nondomestic felid species (Panthera tigris, Lynx rufus, and Panthera uncia) diagnosed with degenerative joint disease to predict safety, contraindications, and likely response to treatment. Patients were then treated utilizing doses extrapolated from domestic cats and following manufacturer guidelines for administration, and clinical response was evaluated over a minimum 2-mon period. Significant improvement was noted in clinical signs in all four animals, resulting in marked improvement in mobility, lameness, activity level, demeanor, and overall quality of life. Frunevetmab presents an excellent adjunctive therapeutic alternative for nondomestic felids suffering from degenerative joint disease and may complement or decrease the need for other conventional therapeutic regimens.

Elastin-specific MR probe for visualization and evaluation of an interleukin-1ß targeted therapy for atherosclerosis.

Atherosclerosis is a chronic inflammatory condition of the arteries and represents the primary cause of various cardiovascular diseases. Despite ongoing progress, finding effective anti-inflammatory therapeutic strategies for atherosclerosis remains a challenge. Here, we assessed the potential of molecular magnetic resonance imaging (MRI) to visualize the effects of 01BSUR, an anti-interleukin-1ß monoclonal antibody, for treating atherosclerosis in a murine model. Male apolipoprotein E-deficient mice were divided into a therapy group (01BSUR, 2 × 0.3 mg/kg subcutaneously, n = 10) and control group (no treatment, n = 10) and received a high-fat diet for eight weeks. The plaque burden was assessed using an elastin-targeted gadolinium-based contrast probe (0.2 mmol/kg intravenously) on a 3 T MRI scanner. T1-weighted imaging showed a significantly lower contrast-to-noise (CNR) ratio in the 01BSUR group (pre: 3.93042664; post: 8.4007067) compared to the control group (pre: 3.70679168; post: 13.2982156) following administration of the elastin-specific MRI probe (p < 0.05). Histological examinations demonstrated a significant reduction in plaque size (p < 0.05) and a significant decrease in plaque elastin content (p < 0.05) in the treatment group compared to control animals. This study demonstrated that 01BSUR hinders the progression of atherosclerosis in a mouse model. Using an elastin-targeted MRI probe, we could quantify these therapeutic effects in MRI.

Anisotropic coarse-grain Monte Carlo simulations of lysozyme, lactoferrin, and NISTmAb by precomputing atomistic models.

We develop a multiscale coarse-grain model of the NIST Monoclonal Antibody Reference Material 8671 (NISTmAb) to enable systematic computational investigations of high-concentration physical instabilities such as phase separation, clustering, and aggregation. Our multiscale coarse-graining strategy captures atomic-resolution interactions with a computational approach that is orders of magnitude more efficient than atomistic models, assuming the biomolecule can be decomposed into one or more rigid bodies with known, fixed structures. This method reduces interactions between tens of thousands of atoms to a single anisotropic interaction site. The anisotropic interaction between unique pairs of rigid bodies is precomputed over a discrete set of relative orientations and stored, allowing interactions between arbitrarily oriented rigid bodies to be interpolated from the precomputed table during coarse-grained Monte Carlo simulations. We present this approach for lysozyme and lactoferrin as a single rigid body and for the NISTmAb as three rigid bodies bound by a flexible hinge with an implicit solvent model. This coarse-graining strategy predicts experimentally measured radius of gyration and second osmotic virial coefficient data, enabling routine Monte Carlo simulation of medically relevant concentrations of interacting proteins while retaining atomistic detail. All methodologies used in this work are available in the open-source software Free Energy and Advanced Sampling Simulation Toolkit.

Imaged capillary isoelectric focusing method development for charge variants of high DAR ADCs.

BACKGROUND: 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. RESULTS: 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. SIGNIFICANCE: 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.

Discovery of potent allosteric antibodies inhibiting EGFR.

In this work, we report the discovery of potent anti-epidermal growth factor receptor (EGFR) allosteric heavy-chain antibodies by combining camelid immunization and fluorescence-activated cell sorting (FACS). After immunization and yeast surface display library construction, allosteric clones were obtained by introducing the labeled EGF Fc fusion protein as an additional criterion for FACS. This sorting method enabled the identification of 11 heavy-chain antibodies that did not compete with the orthosteric ligand EGF for the binding to EGFR. These antibodies bind to a triple-negative breast cancer cell line expressing EGFR with affinities in the picomolar to nanomolar range. Those camelid-derived antibodies also exhibit interesting properties by modulating EGFR affinity for EGF. Moreover, they are also able to inhibit EGF-induced downstream signaling pathways. In particular, we identified one clone that is more potent than the approved blocking antibody cetuximab in inhibiting both PI3K/AKT and MAPK/ERK pathways. Our results suggest that allosteric antibodies may be potential new modalities for therapeutics.

Tuning Responses to Polatuzumab Vedotin in B-cell Lymphoma.

Polatuzumab vedotin, an antibody-drug conjugate targeting CD79B, is the first new drug approved for first-line therapy of diffuse large B-cell lymphoma in more than two decades, although factors determining treatment responses to polatuzumab vedotin remain unknown. Two new studies identified central mechanisms of lower sensitivity, namely reduced accessibility of the CD79B epitope through N-linked glycosylation of CD79B and lower CD79B surface expression levels due to the activity of the KLHL6 E3 ligase. See related article by Corcoran et al., p. 1653 (6) See related article by Meriranta et al. (7).

Advances in immunotoxin engineering: precision therapeutic strategies in modern oncology.

Immunotoxins (ITs) are specialized therapeutic agents designed for targeted treatment, particularly in cancer therapy. They consist of a monoclonal antibody or antibody fragment linked to a potent cytotoxic agent, such as bacterial- or plant-derived toxins like diphtheria toxin, ricin, or pseudomonas exotoxin. The monoclonal antibody component specifically binds to antigens expressed on the surface of target cells, facilitating the internalization of the IT. Once inside the cell, the cytotoxic agent is released, disrupting essential cellular processes and leading to cell death. This targeted approach minimizes damage to healthy tissues while effectively eliminating diseased cells. The production of ITs involves two primary methods: recombinant fusion and chemical conjugation. In recombinant fusion, genetic engineering is used to create a fusion protein that combines the antibody and toxin, ensuring precise control over their ratio and functionality. In chemical conjugation, pre-existing antibodies are chemically linked to toxins, allowing for greater flexibility in combining different antibodies and cytotoxic agents. Each method has its advantages and challenges, influencing the specificity, production complexity, and therapeutic potential of the resulting ITs. As research advances, ITs continue to show promise not only in oncology but also in treating other diseases, including inflammatory conditions and atherosclerosis. The precise targeting and potent effects of ITs make them a valuable tool in the development of new therapeutic strategies.

Rapid lateral flow test for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria differentiation.

The diagnosis of mycobacterial infections, including both the Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), poses a significant global medical challenge. This study proposes a novel approach using immunochromatographic (IC) strip tests for the simultaneous detection of MTBC and NTM. Traditional methods for identifying mycobacteria, such as culture techniques, are hindered by delays in distinguishing between MTBC and NTM, which can affect patient care and disease control. Molecular methods, while sensitive, are resource-intensive and unable to differentiate between live and dead bacteria. In this research, we developed unique monoclonal antibodies (mAbs) against Ag85B, a mycobacterial secretory protein, and successfully implemented IC strip tests named 8B and 9B. These strips demonstrated high concordance rates with conventional methods for detecting MTBC, with positivity rates of 93.9% and 85.9%, respectively. For NTM detection, the IC strip tests achieved a 63.2% detection rate compared to culture methods, considering variations in growth rates among different NTM species. Furthermore, this study highlights a significant finding regarding the potential of MPT64 and Ag85B proteins as markers for MTBC detection. In conclusion, our breakthrough method enables rapid and accurate detection of both MTBC and NTM bacteria within the BACTEC MGIT system. This approach represents a valuable tool in clinical settings for distinguishing between MTBC and NTM infections, thereby enhancing the management and control of mycobacterial diseases. KEY POINTS: • Panel of mAbs for differentiating MTB versus NTM • IC strips for diagnosing MTBC and NTM after the BACTEC MGIT • Combined detection of MTP64 and Ag85B enhances diagnostic accuracy.

The RSV roadmap in children: Lessons learned, paths forward.

Respiratory syncytial virus (RSV) is a threat to infants globally causing bronchiolitis and pneumonia. Despite decades of research, RSV outbreaks occur with only modest advancements in prevention or treatment. Vaccine development faced challenges because past attempts caused enhanced disease and treatment options demonstrated limited efficacy. Recent advancements, including maternal vaccines focusing on the prefusion form of the F glycoprotein are now showing significant benefits in preventing severe RSV-related illness in infants. Additionally, monoclonal antibodies offer prevention directly to newborns within 1 week of birth. These innovations have the potential to substantially change the impact of RSV.

Systematic analysis of Fc mutations designed to enhance binding to Fc-gamma receptors.

A critical attribute of therapeutic antibodies is their ability to engage with humoral or cellular effector mechanisms, and this depends on the ability of the Fc region to bind to complement (C1q) or Fc receptors. Investigators have sought to optimize these effects by engineering the Fc region to bind to a greater or lesser extent to individual receptors. Different approaches have been used in the clinic, but they have not been systematically compared. We have now produced a matched set of anti-CD20 antibodies representing a range of variants and compared their activity in cell-based assays for complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and antibody-dependent phagocytosis using a range of individual Fc receptors. We have also compared the thermal stability of the variants by differential scanning fluorimetry (DSF). The results reveal a spectrum of activities which may be appropriate for different applications.

Claudin 1, 4, 6 and 18 isoform 2 as targets for the treatment of cancer (Review).

The 24 claudin (CLDN) genes in the human genome encode 26 representative CLDN family proteins. CLDNs are tetraspan­transmembrane proteins at tight junctions. Because several CLDN isoforms, such as CLDN6 and CLDN18.2, are specifically upregulated in human cancer, CLDN­targeting monoclonal antibodies (mAbs), antibody­drug conjugates (ADCs), bispecific antibodies (bsAbs) and chimeric antigen receptor (CAR) T cells have been developed. In the present review, CLDN1­, 4­, 6­ and 18.2­targeting investigational drugs in clinical trials are discussed. CLDN18.2­directed therapy for patients with gastric and other types of cancer is the most advanced area in this field. The mouse/human chimeric anti­CLDN18.2 mAb zolbetuximab has a single­agent objective response rate (ORR) of 9%, and increases progression­free and overall survival in combination with chemotherapy. The human/humanized anti­CLDN18.2 mAb osemitamab, and ADCs AZD0901, IBI343 and LM­302, with single­agent ORRs of 28­60%, have been tested in phase III clinical trials. In addition, bsAbs, CAR T cells and their derivatives targeting CLDN4, 6 or 18.2 are in phase I and/or II clinical trials. AZD0901, IBI343, zolbetuximab and the anti­CLDN1 mAb ALE.C04 have been granted fast track designation or priority review designation by the US Food and Drug Administration.

Real-world efficacy and safety of durvalumab-tremelimumab as second-line systemic therapy after atezolizumab-bevacizumab in unresectable hepatocellular carcinoma.

The efficacy and safety of immune-checkpoint inhibitors (ICI) for the treatment of unresectable hepatocellular carcinoma are known. We explored ICI rechallenges with direct switching from 1 ICI regimen to another. This retrospective study included 16 patients who received atezolizumab-bevacizumab (Atezo+Bev) and durvalumab-tremelimumab (Dur+Tre) as the first-line and second-line combination therapy, respectively, at Hiroshima University Hospital. The radiological response and adverse event were evaluated in all patients. Of the 16 patients, 12 were male, and the median age at Atezo+Bev induction was 71 years. The reasons for medication changes were disease progression in 11 patients and adverse events in 5 patients. With Atezo+Bev and Dur+Tre initiation, the Barcelona-Clinic Liver-Cancer stage (A/B/C) progressed in 9/6/3 and 3/4/9 patients and the Child-Pugh classification (A/B/C) progressed in 12/4/0 and 9/6/3 patients, respectively. The disease control rate and overall response rate of Atezo+Bev were 87.5% and 58.3%, respectively, and of Dur+Tre were 62.5% and 0%, respectively. The most common immune-related adverse event in both the Atezo+Bev and Dur+Tre groups was colitis; 3 of the 5 patients with colitis on Atezo+Bev treatment had colitis with Dur+Tre, and 2 had exacerbations. Regarding liver function, ALBI score significantly decreased during Atezo+Bev, but not Dur+Tre, treatment. In patients with colitis following Atezo+Bev, subsequent Dur+Tre treatment may induce colitis recurrence or exacerbation. For immune-related adverse events other than colitis, Dur+Tre could provide relatively safe disease control while maintaining liver function.

A novel dual-epigenetic inhibitor enhances recombinant monoclonal antibody expression in CHO cells.

Epigenetic regulation plays a central role in the regulation of a number of cellular processes such as proliferation, differentiation, cell cycle, and apoptosis. In particular, small molecule epigenetic modulators are key elements that can effectively influence gene expression by precisely regulating the epigenetic state of cells. To identify useful small-molecule regulators that enhance the expression of recombinant proteins in Chinese hamster ovary (CHO) cells, we examined a novel dual-HDAC/LSD1 inhibitor I-4 as a supplement for recombinant CHO cells. Treatment with 2 µM I-4 was most effective in increasing monoclonal antibody production. Despite cell cycle arrest at the G1/G0 phase, which inhibits cell growth, the addition of the inhibitor at 2 µM to monoclonal antibody-expressing CHO cell cultures resulted in a 1.94-fold increase in the maximal monoclonal antibody titer and a 2.43-fold increase in specific monoclonal antibody production. In addition, I-4 significantly increased the messenger RNA levels of the monoclonal antibody and histone H3 acetylation and methylation levels. We also investigated the effect on HDAC-related isoforms and found that interference with the HDAC5 gene increased the monoclonal antibody titer by 1.64-fold. The results of this work provide an effective method of using epigenetic regulatory strategies to enhance the expression of recombinant proteins in CHO cells. KEY POINTS: • HDAC/LSD1 dual-target small molecule inhibitor can increase the expression level of recombinant monoclonal antibodies in CHO cells. • By affecting the acetylation and methylation levels of histones in CHO cells and downregulating HDAC5, the production of recombinant monoclonal antibodies increased. • It provides an effective pathway for applying epigenetic regulation strategies to enhance the expression of recombinant proteins.

Isolation and characterization of IgG3 glycan-targeting antibodies with exceptional cross-reactivity for diverse viral families.

Broadly reactive antibodies that target sequence-diverse antigens are of interest for vaccine design and monoclonal antibody therapeutic development because they can protect against multiple strains of a virus and provide a barrier to evolution of escape mutants. Using LIBRA-seq (linking B cell receptor to antigen specificity through sequencing) data for the B cell repertoire of an individual chronically infected with human immunodeficiency virus type 1 (HIV-1), we identified a lineage of IgG3 antibodies predicted to bind to HIV-1 Envelope (Env) and influenza A Hemagglutinin (HA). Two lineage members, antibodies 2526 and 546, were confirmed to bind to a large panel of diverse antigens, including several strains of HIV-1 Env, influenza HA, coronavirus (CoV) spike, hepatitis C virus (HCV) E protein, Nipah virus (NiV) F protein, and Langya virus (LayV) F protein. We found that both antibodies bind to complex glycans on the antigenic surfaces. Antibody 2526 targets the stem region of influenza HA and the N-terminal domain (NTD) region of SARS-CoV-2 spike. A crystal structure of 2526 Fab bound to mannose revealed the presence of a glycan-binding pocket on the light chain. Antibody 2526 cross-reacted with antigens from multiple pathogens and displayed no signs of autoreactivity. These features distinguish antibody 2526 from previously described glycan-reactive antibodies. Further study of this antibody class may aid in the selection and engineering of broadly reactive antibody therapeutics and can inform the development of effective vaccines with exceptional breadth of pathogen coverage.