CD44 is a type I transmembrane glycoprotein associated with poor prognosis in various solid tumors. Since CD44 plays a critical role in tumor development by regulating cell adhesion, survival, proliferation and stemness, it has been considered a target for tumor therapy. Anti‑CD44 monoclonal antibodies (mAbs) have been developed and applied to antibody‑drug conjugates and chimeric antigen receptor‑T cell therapy. Anti-pan‑CD44 mAbs, C44Mab‑5 and C44Mab‑46, which recognize both CD44 standard (CD44s) and variant isoforms were previously developed. The present study generated a mouse IgG2a version of the anti‑pan‑CD44 mAbs (5‑mG2a and C44Mab‑46‑mG2a) to evaluate the antitumor activities against CD44‑positive cells. Both 5‑mG2a and C44Mab‑46‑mG2a recognized CD44s‑overexpressed CHO‑K1 (CHO/CD44s) cells and esophageal tumor cell line (KYSE770) in flow cytometry. Furthermore, both 5‑mG2a and C44Mab‑46‑mG2a could activate effector cells in the presence of CHO/CD44s cells and exhibited complement-dependent cytotoxicity against both CHO/CD44s and KYSE770 cells. Furthermore, the administration of 5‑mG2a and C44Mab‑46‑mG2a significantly suppressed CHO/CD44s and KYSE770 xenograft tumor development compared with the control mouse IgG2a. These results indicate that 5‑mG2a and C44Mab‑46‑mG2a could exert antitumor activities against CD44‑positive cancers and be a promising therapeutic regimen for tumors.

T cell-mediated islet destruction is a hallmark of autoimmune diabetes. Here, we examined the dynamics and pathogenicity of CD4+ T cell responses to four different insulin-derived epitopes during diabetes initiation in non-obese diabetic (NOD) mice. Single-cell RNA sequencing of tetramer-sorted CD4+ T cells from the pancreas revealed that islet-antigen-specific T cells adopted a wide variety of fates and required XCR1+ dendritic cells for their activation. Hybrid-insulin C-chromogranin A (InsC-ChgA)-specific CD4+ T cells skewed toward a distinct T helper type 1 (Th1) effector phenotype, whereas the majority of insulin B chain and hybrid-insulin C-islet amyloid polypeptide-specific CD4+ T cells exhibited a regulatory phenotype and early or weak Th1 phenotype, respectively. InsC-ChgA-specific CD4+ T cells were uniquely pathogenic upon transfer, and an anti-InsC-ChgA:IAg7 antibody prevented spontaneous diabetes. Our findings highlight the heterogeneity of T cell responses to insulin-derived epitopes in diabetes and argue for the feasibility of antigen-specific therapies that blunts the response of pathogenic CD4+ T cells causing autoimmunity.

Among their many unique biological features, bats are increasingly recognized as a key reservoir of many emerging viruses that cause massive morbidity and mortality in humans. Bats are capable of harboring many of these deadly viruses without any apparent signs of pathology, in a mechanism known as viral disease tolerance. However, the immunological mechanisms behind viral tolerance remain poorly understood. As a non-model organism species, there are very limited research resources and tools available to study bat immunology. In the cave nectar bat Eonycteris spelaea, we have a panel of monoclonal antibodies (mAbs) against major immune markers. An immunophenotyping survey of major immune compartments and barrier sites using these mAbs reveals differences in the immunological landscape of bats.

Therapeutic monoclonal antibodies (mAbs) are crucial in modern medicine due to their effectiveness in treating various diseases. However, the structural complexity of mAbs, particularly their glycosylation patterns, presents challenges for quality control and biosimilarity assessment. This study explores the use of upper-hinge middle-up (UHMU)-level ultra-high-performance liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analysis to improve N-glycan profiling of mAbs. Two specific enzymes, known as IgG degradation enzymes (IGDEs), were used to selectively cleave therapeutic mAbs above the hinge region to separate antibody subunits for further Fc glycan analysis by means of the UHMU/LC-HRMS workflow. The complexity of the mass spectra of IGDEs-digested mAbs was significantly reduced compared to the intact MS level, enabling reliable assignment and relative quantitation of paired Fc glycoforms. The results of the UHMU/LC-HRMS analysis of nine approved therapeutics highlight the significance of this approach for in-depth glycoform profiling.

Therapeutic monoclonal antibody (mAb) products for intravenous (IV) administration generally require aseptic compounding with a commercially available diluent. When the administration site is located away from the preparation site, the prepared dosing solution may need to be transported in a vehicle. The impact of vehicle transportation on the product quality of mAbs needs to be evaluated to define safe handling and transportation conditions for dosing solutions. The design and execution of actual vehicle transportation studies require considerable resources and time. In this study, we systematically developed three different laboratory equipment-based methods that simulate vehicle transportation stresses: orbital shaker (OS), reciprocating shaker (RS), and vibration test system (VTS)-based simulation methods. We assessed their feasibility by comparing the impact on product quality caused by each simulated method with that caused by actual vehicle transportation. Without residual polysorbate 80 (PS80) in the mAb dosing solution, transportation via a cargo van led to a considerable increase in the subvisible particle counts and did not meet the compendial specifications for the light obscuration method. However, the presence of as low as 0.0004%w/v (4 ppm) PS80 in the dosing solution stabilized the mAb against vehicle transportation stresses and met the compendial specifications. Vehicle transportation of an IV bag with headspace resulted in negligible micro air bubbles and foaming in both PS80-free and PS80-containing mAb dosing solutions. These phenomena were found to be comparable to the VTS-based simulated method. However, the OS- and RS-based simulated methods formed significantly more micro air bubbles and foaming in an IV bag with headspace than either actual vehicle transportation or the VTS-based simulated method. Despite the higher interfacial stress (micro air bubbles and foaming) in the dosing solution created by the OS- and RS-based simulated methods, 0.0004%w/v (4 ppm) PS80 in the dosing solution was found to be sufficient to stabilize the mAb. The study shows that under appropriate simulated conditions, the OS-, RS-, and VTS-based simulated methods can be used as practical and meaningful models to assess the impact and risk of vehicle transportation on the quality of mAb dosing solutions.

BACKGROUND: There are pre-existing inequities in asthma care.
OBJECTIVE: We sought to evaluate effect modification by race of the effect of insurance on biologic therapy use in patients with asthma and related diseases.
METHODS: We conducted inverse probability weighted analyses using electronic health records data from 2011 to 2020 from a large health care system in Boston, Mass. We evaluated the odds of not initiating omalizumab or mepolizumab therapy within 1 year of prescription for an approved indication.
RESULTS: We identified 1132 individuals who met study criteria. Twenty-seven percent of these patients had public insurance and 12% belonged to a historically marginalized group (HMG). One-quarter of patients did not initiate the prescribed biologic. Among patients with asthma, individuals belonging to HMG had higher exacerbation rates in the period before initiation compared to non-HMG individuals, regardless of insurance type. Among HMG patients with asthma, those with private insurance were less likely to not initiate therapy compared to those with public insurance (odds ratio [OR]: 0.67, and 95% CI: 0.56-0.79). Among non-HMG with asthma, privately insured and publicly insured individuals had similar rates of not initiating the prescribed biologic (OR: 1.02; 95% CI: 0.95-1.09). Among those publicly insured with asthma, HMGs had higher odds of not initiating therapy compared to non-HMGs (OR: 1.16; 95% CI: 1.03-1.31), but privately insured HMG and non-HMG did not differ significantly (OR: 0.99; 95% CI: 0.91-1.07).
CONCLUSIONS: Publicly insured individuals belonging to HMG are less likely to initiate biologics when prescribed despite having more severe asthma, while there are no inequities by insurance in individuals belonging to other groups.

UNASSIGNED: Tixagevimab-cilgavimab is a combination of 2 mAbs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In December 2021, the Food and Drug Administration issued Emergency Use Authorization for intramuscular injection of tixagevimab-cilgavimab for prophylaxis against SARS-CoV-2 in immunocompromised patients. Shortly thereafter, our clinic distributed tixagevimab-cilgavimab to patients with common variable immunodeficiency.
UNASSIGNED: We sought to evaluate the effectiveness and tolerability of tixagevimab-cilgavimab in a common variable immunodeficiency clinic.
UNASSIGNED: A retrospective chart review from February 1, 2022, to August 1, 2022, of 47 patients with common variable immunodeficiency who were offered tixagevimab-cilgavimab was carried out. Comparative outcomes of treatment and nontreatment groups examined the occurrence of SARS-CoV-2 infection, severity of SARS-CoV-2 infection, and other non-SARS-CoV-2 infections.
UNASSIGNED: Seventy percent of the patients were female; mean age was 49 years. Twenty-three patients received tixagevimab-cilgavimab, and 24 did not receive prophylaxis. In the tixagevimab-cilgavimab group, all were vaccinated for SARS-CoV-2 and 22 were receiving immunoglobulin replacement. One patient was infected with SARS-CoV-2, no patients required emergency care, and 7 patients had non-SARS-CoV-2 infection. In the cohort that did not receive prophylaxis, 21 were vaccinated, and all received immunoglobulin replacement. Two patients tested positive for SARS-CoV-2, 1 patient required emergency care due to SARS-CoV-2 disease severity, and 4 patients had a non-SARS-CoV-2 infection. None of the results showed statistical significance.
UNASSIGNED: Although there is evidence that tixagevimab-cilgavimab can be protective against SARS-CoV-2 in immunocompromised individuals, our data suggest that this benefit may be blunted in patients with common variable immunodeficiency on immunoglobulin replacement. The additional benefit of tixagevimab-cilgavimab in immunocompromised patients already receiving replacement therapy requires further exploration.

The highly conserved and essential Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) has emerged as the leading target for vaccines against the disease-causing blood stage of malaria. However, the features of the human vaccine-induced antibody response that confer highly potent inhibition of malaria parasite invasion into red blood cells are not well defined. Here, we characterize 236 human IgG monoclonal antibodies, derived from 15 donors, induced by the most advanced PfRH5 vaccine. We define the antigenic landscape of this molecule and establish that epitope specificity, antibody association rate, and intra-PfRH5 antibody interactions are key determinants of functional anti-parasitic potency. In addition, we identify a germline IgG gene combination that results in an exceptionally potent class of antibody and demonstrate its prophylactic potential to protect against P. falciparum parasite challenge in vivo. This comprehensive dataset provides a framework to guide rational design of next-generation vaccines and prophylactic antibodies to protect against blood-stage malaria.

Influenza A virus (IAV) is well known for its pandemic potential. While current surveillance and vaccination strategies are highly effective, therapeutic approaches are often short-lived due to the high mutation rates of IAV. Recently, monoclonal antibodies (mAbs) have emerged as a promising therapeutic approach, both against current strains and future IAV pandemics. In addition to mAbs, several antibody-like alternatives exist, which aim to improve upon mAbs. Among these, Affimers stand out for their short development time, high expression levels in Escherichia coli, and animal-free production. In this study, we utilized the Affimer platform to isolate and produce specific and potent inhibitors of IAV. Using a monomeric version of the IAV trimeric hemagglutinin (HA) fusion protein, we isolated 12 Affimers that inhibit IAV infection in vitro. Two of these Affimers were characterized in detail and exhibited nanomolar-binding affinities to the target H3 HA protein, specifically binding to the HA1 head domain. Cryo-electron microscopy (cryo-EM), employing a novel spray approach to prepare cryo-grids, allowed us to image HA-Affimer complexes. Combined with functional assays, we determined that these Affimers inhibit IAV by blocking the interaction of HA with the host-cell receptor, sialic acid. Furthermore, these Affimers inhibited IAV strains closely related to the one used for their isolation. Overall, our results support the use of Affimers as a viable alternative to existing targeted therapies for IAV and highlight their potential as diagnostic reagents.
OBJECTIVE: Influenza A virus is one of the few viruses that can cause devastating pandemics. Due to the high mutation rates of this virus, annual vaccination is required, and antivirals are short-lived. Monoclonal antibodies present a promising approach to tackle influenza virus infections but are associated with some limitations. To improve on this strategy, we explored the Affimer platform, which are antibody-like proteins made in bacteria. By performing phage-display against a monomeric version of influenza virus fusion protein, an established viral target, we were able to isolate Affimers that inhibit influenza virus infection in vitro. We characterized the mechanism of inhibition of the Affimers by using assays targeting different stages of the viral replication cycle. We additionally characterized HA-Affimer complex structure, using a novel approach to prepare samples for cryo-electron microscopy. Overall, these results show that Affimers are a promising tool against influenza virus infection.

With some exceptions, global policymakers have recommended against the use of existing monoclonal antibodies in COVID-19 due to loss of neutralization of newer variants. The purpose of this study was to investigate the impact of Ronapreve on compartmental viral replication using paradigms for susceptible and insusceptible variants. Virological efficacy and impact on pathogenicity was assessed in K18-hACE2 mice inoculated with either the Delta or BA.1 Omicron variants. Ronapreve reduced sub-genomic viral RNA levels in lung and nasal turbinate, 4 and 6 days post-infection, for the Delta variant but not the Omicron variant. It also blocked brain infection, which is seen with high frequency in K18-hACE2 mice after Delta variant infection. At day 6, the inflammatory response to lung infection with the Delta variant was altered to a multifocal granulomatous inflammation in which the virus appeared to be confined. The current study provides evidence of an altered tissue response to SARS-CoV-2 after treatment with a monoclonal antibody combination that retains neutralization activity. These data demonstrate that experimental designs that reflect treatment use cases are achievable in animal models for monoclonal antibodies. Extreme caution should be taken when interpreting prophylactic experimental designs that may not be representative of treatment.IMPORTANCEFollowing the emergence of the SARS-CoV-2 Omicron variant, the WHO recommended against the use of Ronapreve in its COVID-19 treatment guidelines due to a lack of efficacy based on current pharmacokinetic-pharmacodynamic understanding. However, the continued use of Ronapreve, specifically in vulnerable patients, was advocated by some based on in vitro neutralization data. Here, the virological efficacy of Ronapreve was demonstrated in both the lung and brain compartments using Delta as a paradigm for a susceptible variant. Conversely, a lack of virological efficacy was demonstrated for the Omicron variant. Comparable concentrations of both monoclonal antibodies were observed in the plasma of Delta- and Omicron-infected mice. This study made use of a reliable murine model for SARS-CoV-2 infection, an experimental design reflective of treatment, and demonstrated the utility of this approach when assessing the effectiveness of monoclonal antibodies.