Antibody Binding Research Articles

Rapid in silico directed evolution by a protein language model with EVOLVEpro.

Directed protein evolution is central to biomedical applications but faces challenges like experimental complexity, inefficient multi-property optimization, and local maxima traps. While in silico methods using protein language models (PLMs) can provide modeled fitness landscape guidance, they struggle to generalize across diverse protein families and map to protein activity. We present EVOLVEpro, a few-shot active learning framework that combines PLMs and regression models to rapidly improve protein activity. EVOLVEpro surpasses current methods, yielding up to 100-fold improvements in desired properties. We demonstrate its effectiveness across six proteins in RNA production, genome editing, and antibody binding applications. These results highlight the advantages of few-shot active learning with minimal experimental data over zero-shot predictions. EVOLVEpro opens new possibilities for AI-guided protein engineering in biology and medicine.

Anti-SARS-CoV-2 serology based on ancestral RBD antigens does not correlate with the presence of neutralizing antibodies against Omicron variants.

Anti-SARS-CoV-2 serology was developed in 2020 in response to the COVID-19 pandemic to diagnose SARS-CoV-2 infection and monitor an individual's immunity following natural infection or vaccination. Given the relationship between neutralizing antibody titers and protection against severe infection, many studies have evaluated the correlation between serology tests and neutralization assays in the pre-Omicron era. An important potential clinical use of serology, which explores binding antibodies, is estimating an individual's level of protection against new infection, particularly in immunosuppressed individuals and those at risk of severe COVID. However, in the Omicron era, as new viruses evade the immunity induced by previous infections and vaccination, the correlation between binding antibody levels determined by serological assays developed from ancestral antigens and neutralizing antibody titers against new viruses should be re-examined in order to determine whether these assays should be optimized by adapting antigens to the circulating SARS-CoV-2 strains.

Sustained Endocytosis Inhibition via Locally-Injected Drug-Eluting Hydrogel Improves ADCC-Mediated Antibody Therapy in Colorectal Cancer.

The epidermal growth factor receptor (EGFR) is a validated therapeutic target for RAS/RAF wild-type colorectal cancer (CRC). However, monoclonal antibody-based anti-EGFR therapies such as cetuximab have limited effectiveness. Herein, it is identified that EGFR internalization is associated with poor treatment response and prognosis in patients with CRC, based on a retrospective analysis of patients treated with cetuximab. It is further demonstrated that the endocytosis inhibitor prochlorperazine (PCZ) can move EGFR, which is hidden inside the cell, to the cell surface to improve therapeutic antibody binding. Thus, a thermosensitive hydrogel co-loaded with cetuximab and PCZ (Gel@Cmab/PCZ) is constructed for sustained inhibition of endocytosis and effective cetuximab delivery. Peritumoral injection of Gel@Cmab/PCZ shows strong antitumor efficacy in subcutaneous and orthotopic CRC tumor models and completely abrogated liver metastasis when combined with chemotherapy. In a humanized patient-derived xenograft model, a single injection of Gel@Cmab/PCZ with one-third of theconventional cetuximab dose achieved 91% tumor growth inhibition, which promoted NK cell infiltration into tumor tissues and their antibody-dependent cell-mediated cytotoxicity effect. This study represents a novel strategy to boost the monoclonal antibody-mediated anti-tumor response in CRC.

Nanoparticles in Allergen‐Delivery Systems for Allergen‐Specific Immunotherapy

AbstractAllergen‐specific immunotherapy (AIT) has demonstrated its ability to induce desensitization, resulting in reduced allergen‐specific immunoglobulin E (sIgE) accompanied by increased clinical thresholds. However, ensuring safety during therapy, especially with oral immunotherapy, and achieving long‐term tolerance continue to be significant challenges. To address these issues, a concept of nanoencapsulation of allergens has emerged. This paper reviews biodegradable and non‐biodegradable nanoparticles as an allergen‐delivery system, as well as adjuvants for the improvement of the efficacy of AIT. Of all the nanoparticles reviewed, polymethyl methacrylate (PMMA) and chitosan are the most popular nanoparticles for encapsulating macromolecular allergens for oral immunotherapy. Although poly(lactic‐co‐glycolic acid) (PLGA) demonstrates higher stability in the gastrointestinal environment and allergen‐loaded PLGA attenuates the sIgE antibody binding in a murine model, it has inconsistent loading capacity and is difficult to reproduce. Studies on biodistribution, pharmacokinetics, and pharmacodynamics of nanoparticles, however, should be highlighted to ensure the long‐term safety profile of utilizing nanoparticles in immunotherapy. In this regard, encapsulation efficiency and release behavior of allergens from nanoparticles are important components in predicting the safety and efficacy of treatments. The stability, reproducibility, and scalability of encapsulated allergens should also be considered for the translation to clinical applications.

Clearing-enabled light sheet microscopy as a novel method for three-dimensional mapping of the sensory innervation of the mouse knee.

A major barrier that hampers our understanding of the precise anatomic distribution of pain sensing nerves in and around the joint is the limited view obtained from traditional two dimensional (D) histological approaches. Therefore, our objective was to develop a workflow that allows examination of the innervation of the intact mouse knee joint in 3D by employing clearing-enabled light sheet microscopy. We first surveyed existing clearing protocols (SUMIC, PEGASOS, and DISCO) to determine their ability to clear the whole mouse knee joint, and discovered that a DISCO protocol provided the optimal transparency for light sheet microscopy imaging. We then modified the DISCO protocol to enhance binding and penetration of antibodies used for labeling nerves. Using the pan-neuronal PGP9.5 antibody, our protocol allowed 3D visualization of innervation in and around the mouse knee joint. We then implemented the workflow in mice intra-articularly injected with nerve growth factor (NGF) to determine whether changes in the nerve density can be observed. Both 3D and 2D analytical approaches of the light sheet microscopy images demonstrated quantifiable changes in midjoint nerve density following 4 weeks of NGF injection in the medial but not in the lateral joint compartment. We provide, for the first time, a comprehensive workflow that allows detailed and quantifiable examination of mouse knee joint innervation in 3D.

Abstract 4117454: PCSK9 Inhibitors for ASCVD Risk Reduction in Asian Populations — a meta-analysis of efficacy and safety profiles

Background: Dyslipidemia is increasingly prevalent in the Asia-Pacific region, correlating with higher mortality rates for ASCVD among this population. Statins, the cornerstone for dyslipidemia management, face higher intolerance in Asians compared to other races. PCSK9 inhibitors have emerged as a promising therapeutic additive to other lipid-lowering therapies. However, current trials predominantly involve caucasian populations, emphasizing the need for efficacy data across other ethnic groups. This meta-analysis aims to analyze the efficacy and safety profile of PCSK9i in Asian populations at high risk for ASCVD. Methods: We searched PubMed, Scopus, and Cochrane for RCTs from the past 10 years on PCSK9i vs. placebo in Asian populations at risk for ASCVD. Efficacy was measured by the mean difference in LDL levels from baseline. Safety parameters included ALT/AST, CK levels, and binding antibodies. Analysis was done with Review Manager, assessing heterogeneity with I^2 statistics. Results: Eleven studies in Singapore, Japan, the Philippines, India, South Korea, China, and Taiwan included 5443 patients (73% male, mean age 60.6, mean baseline LDL 114 mg/dL) with follow-up from 12 weeks to 16 months. Inclisiran was used in 3 studies, evolocumab in 5, alirocumab in 2, and tafolecimab in 1, alongside statins or ezetimibe. PCSK9i reduced LDL by -74.21 mg/dL and increased the likelihood of >50% LDL reduction compared to placebo (RR: 37.41, 95% CI: 16.31-85.82, P < 0.00001; I^2: 0%). PCSK9i significantly improve the achievement of LDL levels <70 mg/dL compared to placebo (RR: 15.77; 95% CI: 7.12 - 34.91, P < 0.00001; I^2: 82%) Adverse events showed a non-significant risk of >3x ULN increase in ALT/AST ( RR 0.58; 95% CI: 0.33-1.05; P = 0.78, I^2: 0%) and >5x ULN increase in creatine kinase (RR 0.32; 95% CI: 0.07-1.49; P = 0.97; I^2 = 0%). No significant difference in binding antibodies was observed (RR: 2.50, 95% CI: 0.13-49.47, P = 0.55; I^2 = 65%) Conclusion: In Asian populations, PCSK9 inhibitors effectively lower LDL levels without significant adverse events. The considerable heterogeneity in LDL reduction may result from variations in dosing, different agents used, baseline LDL levels, and geographical diversity. Future research should explore effects across more ethnicities to enhance generalizability.

Neutralizing antibody correlate of protection against severe-critical COVID-19 in the ENSEMBLE single-dose Ad26.COV2.S vaccine efficacy trial

Assessment of immune correlates of severe COVID-19 has been hampered by the low numbers of severe cases in COVID-19 vaccine efficacy (VE) trials. We assess neutralizing and binding antibody levels at 4 weeks post-Ad26.COV2.S vaccination as correlates of risk and of protection against severe-critical COVID-19 through 220 days post-vaccination in the ENSEMBLE trial (NCT04505722), constituting ~4.5 months longer follow-up than our previous correlates analysis and enabling inclusion of 42 severe-critical vaccine-breakthrough cases. Neutralizing antibody titer is a strong inverse correlate of severe-critical COVID-19, with estimated hazard ratio (HR) per 10-fold increase 0.35 (95% CI: 0.13, 0.90). In a multivariable model, HRs are 0.31 (0.11, 0.89) for neutralizing antibody titer and 1.22 (0.49, 3.02) for anti-Spike binding antibody concentration. VE against severe-critical COVID-19 rises with neutralizing antibody titer: 63.1% (95% CI: 40.0%, 77.3%) at unquantifiable [<4.8975 International Units (IU)50/ml], 85.2% (47.2%, 95.3%) at just-quantifiable (5.2 IU50/ml), and 95.1% (81.1%, 96.9%) at 90th percentile (30.2 IU50/ml). At the same titers, VE against moderate COVID-19 is 32.5% (11.8%, 48.4%), 33.9% (19.1%, 59.3%), and 60.7% (40.4%, 76.4%). Protection against moderate vs. severe disease may require higher antibody levels, and very low antibody levels and/or other immune responses may associate with protection against severe disease.

Protein-Protein Interaction Networks Derived from Classical and Machine Learning-Based Natural Language Processing Tools.

The study of protein-protein interactions (PPIs) provides insight into various biological mechanisms, including the binding of antibodies to antigens, enzymes to inhibitors or promoters, and receptors to ligands. Recent studies of PPIs have led to significant biological breakthroughs. For example, the study of PPIs involved in the human:SARS-CoV-2 viral infection mechanism aided in the development of SARS-CoV-2 vaccines. Though several databases exist for the manual curation of PPI networks, text mining methods have been routinely demonstrated as useful alternatives for newly studied or understudied species, where databases are incomplete. Here, the relationship extraction performance of several open-source classical text processing, machine learning (ML)-based natural language processing (NLP), and large language model (LLM)-based NLP tools was compared. Overall, our results indicated that networks derived from classical methods tend to have high true positive rates at the expense of having overconnected networks, ML-based NLP methods have lower true positive rates but networks with the closest structures to the target network, and LLM-based NLP methods tend to exist between the two other approaches, with variable performances. The selection of a specific NLP approach should be tied to the needs of a study and text availability, as models varied in performance due to the amount of text provided.

Longitudinal Analysis of Binding Antibody Levels Against 39 Human Adenovirus Types in Sera from 60 Regular Blood Donors from Greifswald, Germany, over 5 Years from 2018 to 2022.

Adenoviruses are important human pathogens that are widespread and mainly associated with respiratory and gastrointestinal infections. In a previous study on human adenovirus (HAdV) seroprevalence, we observed reduced binding antibody levels against a range of HAdV types in sera collected from students in 2021 compared to sera collected before the SARS-CoV-2 pandemic. In this follow-up study, we wanted to verify this observation in a cohort of regular blood donors for whom serial samples were available. Therefore, HAdV-specific binding antibody levels were analyzed in sera collected over a 5-year period from 2018 to 2022 in a cohort of 60 regular donors to the blood bank of the University Hospital in Greifswald, Germany. Using ELISA-based assays, we quantified the binding antibody responses against 39 HAdV types. On the cohort level, we found largely stable antibody levels over the analyzed time period, with the highest antibody responses against HAdV-C1, -D25, -D26, -E4, -D10, -D27, -C5, -D75, -C2, and -C6. Only minor but significant reductions in comparison to the first serum samples from 2018 were detected for antibody levels in 2021 and 2022 against the low-prevalent types HAdV-A31, -D8, -D20, -D37, -D65, and -D69. On the other hand, we detected fluctuations in antibody levels on the individual level, with strong increases in antibody levels indicative of novel antigen contact. Interestingly, we frequently found simultaneous changes in antibody responses against multiple HAdV types, resulting in strong correlations of antibody responses against distinct clusters of HAdVs suggesting extensive cross-reactivity of HAdV-specific antibodies. To our knowledge, this is the first study of antibodies against a broad range of HAdV types in serum samples collected from a cohort of individuals over a prolonged period, and our data provide important insight into the long-term stability of HAdV-specific antibody levels. In this cohort of regular blood donors, we did not observe any major impact of the SARS-CoV-2 pandemic on HAdV immunity. Correlations of changes in antibody levels against different types indicate cross-reactivity of HAdV-specific antibodies that are important to consider for HAdV vector development. Our data also reveal possible candidates for future development of HAdV-based vectors.

Ranking Antibody Binding Epitopes and Proteins Across Samples from Whole Proteome Tiled Linear Peptides.

Ultradense peptide binding arrays that can probe millions of linear peptides comprising the entire proteomes of human or mouse, or hundreds of thousands of microbes, are powerful tools for studying the antibody repertoire in serum samples to understand adaptive immune responses. There are few tools for exploring high-dimensional, significant and reproducible antibody targets for ultradense peptide binding arrays at the linear peptide, epitope (grouping of adjacent peptides), and protein level across multiple samples/subjects (i.e. epitope spread or immunogenic regions of proteins) for understanding the heterogeneity of immune responses. We developed HERON (Hierarchical antibody binding Epitopes and pROteins from liNear peptides), an R package, which identifies immunogenic epitopes, using meta-analyses and spatial clustering techniques to explore antibody targets at various resolution and confidence levels, that can be found consistently across a specified number of samples through the entire proteome to study antibody responses for diagnostics or treatment. Our approach estimates significance values at the linear peptide (probe), epitope, and protein level to identify top candidates for validation. We test the performance of predictions on all three levels using correlation between technical replicates and comparison of epitope calls on two datasets, which shows HERON's competitiveness in estimating false discovery rates and finding general and sample-level regions of interest for antibody binding. The HERON R package is available at Bioconductor https://bioconductor.org/packages/release/bioc/html/HERON.html. Supplementary data are available at Bioinformatics online.

Quantitative SARS-CoV-2 Spike Receptor-Binding Domain and Neutralizing Antibody Titers in Previously Infected Persons, United States, January 2021-February 2022.

We studied SARS-CoV-2 binding and neutralizing antibody titers among previously infected persons in the United States over time. We assayed SARS-CoV-2 spike protein receptor-binding domain and neutralizing antibody titers for a convenience sample of residual clinical serum specimens that had evidence of prior SARS-CoV-2 infection gathered during January 2021-February 2022. We correlated titers and examined them by age group (<18, 18-49, 50-64, and >65 years) across 4 different SARS-CoV-2 variant epochs. Among selected specimens, 30,967 had binding antibody titers and 744 had neutralizing titers available. Titers in specimens from children and adults correlated. In addition, mean binding antibody titers increased over time for all age groups, and mean neutralization titers increased over time for persons 16-49 and >65 years of age. Incorporating binding and neutralization antibody titers into infectious disease surveillance could provide a clearer picture of overall immunity and help target vaccination campaigns.

Enterovirus Antibodies: Friends and Foes.

Enteroviruses (EV) initiate replication by binding to their cellular receptors, leading to the uncoating and release of the viral genome into the cytosol of the host cell. Neutralising antibodies (NAbs) binding to epitopes on enteroviral capsid proteins can inhibit this infectious process through several mechanisms of neutralisation in vitro. Fc-mediated antibody effector functions such as antibody-dependent cell-mediated cytotoxicity and antibody-dependent cellular phagocytosis have also been described for some EV. However, antibody binding to virions does not always result in viral neutralisation. Non-neutralising antibodies, or sub-neutralising concentrations of antibodies, can enhance infection of viruses, leading to more severe pathologies. This phenomenon, known as antibody-dependent enhancement (ADE) of infection, has been described in vitro and/or in vivo for EV including poliovirus, coxsackievirus B and EV-A71. It has been shown that ADE of EV infection is mediated by FcγRs expressed by monocytes, macrophages, B lymphocytes and granulocytes. Antibodies play a crucial role in the diagnosis and monitoring of infections. They are valuable markers that have been used to establish a link between enteroviral infection and chronic diseases such as type 1 diabetes. Monoclonal and polyclonal antibodies targeting enteroviral proteins have been developed and shown to be effective to prevent or combat EV infections in vitro and in vivo. In addition, vaccines are under development, and clinical trials of vaccines are underway or have been completed, providing hope for the prevention of diseases due to EV. However, the ADE of the infection should be considered in the development of anti-EV antibodies or safe vaccines.

Ecological and Reproductive Cycles Drive Henipavirus Seroprevalence in the African Straw-Coloured Fruit Bat (Eidolon helvum).

Bats are known to host zoonotic viruses, including henipaviruses that cause high fatality rates in humans (Nipah virus and Hendra virus). However, the determinants of zoonotic spillover are generally unknown, as the ecological and demographic drivers of viral circulation in bats are difficult to ascertain without longitudinal data. Here we analyse serological data collected from African straw-coloured fruit bats (Eidolon helvum) in Ghana over the course of 2 years and across four sites, comprising three wild roosts and one captive colony. We focus on antibody affinity to five henipavirus antigens: Ghanaian bat henipavirus (GhV), Nipah virus (NiV), Hendra virus (HeV), Mojiang virus (MojV) and Cedar virus (CedV). In the wild roosts, we detected seasonal variations in henipavirus antibody binding, possibly associated with bat life-history cycles and migration patterns. In the captive colony, we identified increases in antibody affinity levels among pregnant bats, suggesting possible shifts in the immune system during pregnancy. These bats then pass maternal antibodies to their pups, which wane before antibody affinity levels rise later in life following initial infections and/or reactivation of latent infections. These results improve our understanding of the links between bat ecology and viral circulation, including for GhV, a locally-circulating African henipavirus.

A Synthetic Oligosaccharide Resembling Francisella tularensis Strain 15 O-Antigen Capsular Polysaccharide as a Lead for Tularemia Diagnostics and Therapeutics.

Francisella tularensis, a category A bioterrorism agent, causes tularemia in many animal species. F. tularensis subspecies tularensis (type A) and holarctica (type B) are mainly responsible for human tularemia. The high mortality rate of 30-60 % caused by F. tularensis subspecies tularensis if left untreated and the aerosol dispersal renders this pathogen a dangerous bioagent. While a live attenuated vaccine strain (LVS) of F. tularensis type B does not provide sufficient protection against all forms of tularemia infections, a significant level of protection against F. tularensis has been observed for both passive and active immunization of mice with isolated O-antigen capsular polysaccharide. Well-defined, synthetic oligosaccharides offer an alternative approach towards the development of glycoconjugate vaccines. To identify diagnostics and therapeutics leads against tularemia, a collection of F. tularensis strain 15 O-antigen capsular polysaccharide epitopes were chemically synthesized. Glycan microarrays containing synthetic glycans were used to analyze the sera of tularemia-infected and non-infected animals and revealed the presence of IgG antibodies against the glycans. Two disaccharide (13 and 18), both bearing a unique formamido moiety, were identified as minimal glycan epitopes for antibody binding. These epitopes are the starting point for the development of diagnostics and therapeutics against tularemia.

A Synthetic Oligosaccharide Resembling Francisella tularensis Strain 15 O‐Antigen Capsular Polysaccharide as a Lead for Tularemia Diagnostics and Therapeutics

AbstractFrancisella tularensis, a category A bioterrorism agent, causes tularemia in many animal species. F. tularensis subspecies tularensis (type A) and holarctica (type B) are mainly responsible for human tularemia. The high mortality rate of 30–60 % caused by F. tularensis subspecies tularensis if left untreated and the aerosol dispersal renders this pathogen a dangerous bioagent. While a live attenuated vaccine strain (LVS) of F. tularensis type B does not provide sufficient protection against all forms of tularemia infections, a significant level of protection against F. tularensis has been observed for both passive and active immunization of mice with isolated O‐antigen capsular polysaccharide. Well‐defined, synthetic oligosaccharides offer an alternative approach towards the development of glycoconjugate vaccines. To identify diagnostics and therapeutics leads against tularemia, a collection of F. tularensis strain 15 O‐antigen capsular polysaccharide epitopes were chemically synthesized. Glycan microarrays containing synthetic glycans were used to analyze the sera of tularemia‐infected and non‐infected animals and revealed the presence of IgG antibodies against the glycans. Two disaccharide (13 and 18), both bearing a unique formamido moiety, were identified as minimal glycan epitopes for antibody binding. These epitopes are the starting point for the development of diagnostics and therapeutics against tularemia.

Polysaccharide, Conjugate, and mRNA-based Vaccines are Immunogenic in Patients with Netherton Syndrome

BackgroundNetherton syndrome (NS) is a rare, severe genetic skin disorder, currently classified as an inborn error of immunity (IEI) due to previously reported immune dysregulation. We recently reported the results of an immunological evaluation showing no evidence for a relevant B- and/or T-cell mediated immunodeficiency, but immune responses after vaccination were not evaluated in that study. Therefore, we evaluated immune responses to three vaccine platforms in adult NS patients to further investigate the presence of a clinically relevant B- and/or T-cell immunodeficiency.MethodsVaccination responses in eight adult NS patients were assessed in a cross-sectional study performed between January and August 2022. Clinical patient data were retrospectively retrieved from electronic patient files. Immune responses to a polysaccharide Streptococcus pneumoniae vaccine (PPV23) and conjugate Haemophilus influenzae type b vaccine (ActHiB) were measured. SARS-CoV-2-specific (functional) antibody and T-cell responses following booster vaccination with an mRNA-based COVID-19 vaccine were compared to controls.ResultsNone of the included patients suffered from recurrent and/or severe infections that could be attributed to a B- and/or T-cell immunodeficiency. ActHiB induced immune responses were normal in 7/7 NS patients. PPV23 induced responses were absent in 1/7, diminished in 2/7, and normal in 4/7 patients. Levels of SARS-CoV-2-specific binding and neutralizing antibodies after mRNA-based COVID-19 booster vaccination in NS patients were comparable to controls. SARS-CoV-2-specific CD4 + T-cell responses were detectable in all NS patients. In contrast, SARS-CoV-2-specific CD8 + T-cell responses were detectable in only 2/6 NS patients. T-cell responses to a positive control antigen pool were comparable to controls.ConclusionsVaccine-induced immune responses were detectable after polysaccharide, conjugate and mRNA-based vaccination in our cohort of NS patients. A spectrum of responsiveness to vaccine challenges was found, with the ranges of vaccine responses overlapping those demonstrated in healthy control populations.

Isolation of antibodies to hypochlorite-modified low-density lipoproteins from human serum and study of their specificity

BACKGROUND: Modified low-density lipoproteins have immunogenic properties and induce the production of antibodies. In this case, HOCl promotes the formation of subsequent active halogen-containing compounds interacting with proteins and lipid parts of low-density lipoproteins, which leads to their modification and the production of antibodies to them. AIM: The aim of this work is to isolate antibodies to hypochlorite modified low-density lipoproteins from human blood sera and study their specificity. MATERIALS AND METHODS: Malondialdehyde, acetic anhydride and sodium hypochlorite were used to obtain modified low-density lipoproteins. IgG antibodies to hypochlorite modified low-density lipoproteins were isolated by affinity chromatography. The total IgG fraction antibodies was previously isolated from human blood serum using MabSelect Xtra. The specific antibodies to hypochlorite modified low-density lipoproteins were isolated from this IgG pool by affinity chromatography. CNBr-Sepharose 4B conjugated with human serum albumin modified with NaOCl was used as a sorbent. The specificity of antibodies against hypochlorite modified low-density lipoproteins was tested using a competitive enzyme-linked immunosorbent assay. The competitors were hypochlorite modified low-density lipoproteins, acetic anhydride modified low-density lipoproteins and malondialdehyde modified low-density lipoproteins in concentrations (1–250 μg/ml). RESULTS: IgG antibodies against hypochlorite-modified proteins that interact with hypochlorite modified low-density lipoproteins were detected in human blood. According to ELISA date the binding of the isolated antibodies to hypochlorite modified low-density lipoproteins was almost completely inhibited only by appropriately modified low-density lipoproteins, that is, hypochlorite modified low-density lipoproteins, but not native low-density lipoproteins or acetic anhydride modified low-density lipoproteins. Malondialdehyde modified low-density lipoproteins also showed some competitive activity, but much weaker than hypochlorite modified low-density lipoproteins. Hypochlorite modified low-density lipoproteins itself and, to a lesser extent, malondialdehyde modified low-density lipoproteins competed for binding with antibodies of human serum to hypochlorite modified low-density lipoproteins. Acetic anhydride modified low-density lipoproteins and native low-density lipoproteins did not reduce the efficiency of antibody binding to their antigen. CONCLUSIONS: Hypochlorite modified low-density lipoproteins forms epitopes independent of other low-density lipoproteins modifications studied. These epitopes are responsible for the formation of specific antibodies.

Delineating the functional activity of antibodies with cross-reactivity to SARS-CoV-2, SARS-CoV-1 and related sarbecoviruses.

The recurring spillover of pathogenic coronaviruses and demonstrated capacity of sarbecoviruses, such SARS-CoV-2, to rapidly evolve in humans underscores the need to better understand immune responses to this virus family. For this purpose, we characterized the functional breadth and potency of antibodies targeting the receptor binding domain (RBD) of the spike glycoprotein that exhibited cross-reactivity against SARS-CoV-2 variants, SARS-CoV-1 and sarbecoviruses from diverse clades and animal origins with spillover potential. One neutralizing antibody, C68.61, showed remarkable neutralization breadth against both SARS-CoV-2 variants and viruses from different sarbecovirus clades. C68.61, which targets a conserved RBD class 5 epitope, did not select for escape variants of SARS-CoV-2 or SARS-CoV-1 in culture nor have predicted escape variants among circulating SARS-CoV-2 strains, suggesting this epitope is functionally constrained. We identified 11 additional SARS-CoV-2/SARS-CoV-1 cross-reactive antibodies that target the more sequence conserved class 4 and class 5 epitopes within RBD that show activity against a subset of diverse sarbecoviruses with one antibody binding every single sarbecovirus RBD tested. A subset of these antibodies exhibited Fc-mediated effector functions as potent as antibodies that impact infection outcome in animal models. Thus, our study identified antibodies targeting conserved regions across SARS-CoV-2 variants and sarbecoviruses that may serve as therapeutics for pandemic preparedness as well as blueprints for the design of immunogens capable of eliciting cross-neutralizing responses.

Divergence of variant antibodies following SARS-CoV-2 booster vaccines in myeloma and impact of hybrid immunity

Hematological malignancies are associated with an increased risk of complications during SARS-CoV-2 infections. Primary series or monovalent booster vaccines reduce disease severity, hospitalization, and death among multiple myeloma patients. We characterized virus-neutralizing and spike-binding antibody profiles following monovalent (WA1) or bivalent (WA1/BA.5) SARS-CoV-2 booster vaccination in MM patients. Bivalent vaccination improved the breadth of binding antibodies but not neutralization activity against contemporary variants. Hybrid immunity and immune imprinting impact vaccine-elicited immunity.

Siltuximab for chimeric antigen receptor T-cell therapy–related CRS and ICANS: a multicenter retrospective analysis

AbstractChimeric antigen receptor T-cell (CAR-T) therapies are effective in many hematologic malignancies; however, adverse events including cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) can affect a significant number of patients. Those who develop refractory CRS or ICANS have few treatment options. Siltuximab, a monoclonal antibody binding circulating interleukin-6, has been proposed to have clinical activity in both CRS and ICANS. We conducted a multicenter retrospective analysis of siltuximab treatment for CRS and ICANS after CAR-T therapy in a real-world cohort from 6 academic centers. Fifty-four patients were evaluated. Sixteen patients had CRS previously treated with tocilizumab and 17 patients had ICANS previously treated with steroids. Of the patients with CRS at the time of siltuximab, 75% had improvement in CRS grade. Of the patients with ICANS at the time of siltuximab, 60% had improvement in ICANS grade. To our knowledge, this is the largest cohort of patients treated with siltuximab for CRS and/or ICANS after CAR-T therapies. Siltuximab appeared to be effective for both CRS and ICANS, including previously treated toxicities. These data support the use of siltuximab in CRS and ICANS as well as provide rationale for future prospective studies.