Serum levels of immunoglobulins (IgG, IgA, IgM) in a general adult population and their relationship with alcohol consumption, smoking and common metabolic abnormalities

Prediction of human pharmacokinetics of Fc-engineered therapeutic monoclonal antibodies using human FcRn transgenic mice

Human FcRn transgenic mice (Tg32) have been widely used to evaluate the pharmacokinetics of mAbs and predict human pharmacokinetics. This study aims to establish an approach for predicting the human pharmacokinetics of Fc-engineered mAbs with enhanced FcRn binding mutations using Tg32 mice. MAbs were intravenously administered at 10 mg/kg in the absence or presence of IVIG (1000 mg/kg) in Tg32 mice. Pharmacokinetic parameters (CL, Q, Vc, and Vp) estimated in Tg32 mice were compared with clinical data. Optimal allometric scaling exponents were determined to improve the accuracy of human pharmacokinetic predictions for Fc-engineered mAbs. Moreover, we predicted the plasma concentration-time profile after IV injection in humans using parameters estimated based on an optimized exponent. While normal mAbs exhibited a higher CL in the presence of IVIG compared to its absence, Fc-engineered mAbs showed comparable CL in both conditions. The larger difference in CL between normal and Fc-engineered mAbs observed in the presence of IVIG closely matched clinical study results. A significant positive correlation between Tg32 mice and humans was observed in the CL of Fc-engineered mAbs in both the absence and presence of IVIG. The estimated optimal exponents for CL, Q, Vc, and Vp were 0.73, 0.60, 0.95, and 0.87, respectively. Using these exponents, the plasma mAb concentration-time profile after IV injection in humans was accurately predicted. This study establishes a robust methodology for accurately predicting the human pharmacokinetics of Fc-engineered mAbs using Tg32 mice, achieving prediction accuracy comparable to that of cynomolgus monkeys. This approach, as a viable alternative to cynomolgus monkeys, can accelerate the preclinical development of promising Fc-engineered mAbs with enhanced FcRn binding.

Surrogate Markers of Intestinal Permeability, Bacterial Translocation and Gut-Vascular Barrier Damage Across Stages of Cirrhosis

BACKGROUND AND AIMS

Portal hypertension, gut barrier dysfunction, and pathological bacterial translocation are hallmarks of cirrhosis driving complications. As measuring gut barrier function is demanding, surrogate markers have been proposed, but their intercorrelation and applicability across different stages of advanced liver disease, particularly in acute-on-chronic liver failure (ACLF), are largely unknown.

METHODS

Proposed markers of gut barrier dysfunction and bacterial translocation were quantified in sera from 160 patients with cirrhosis across different disease stages of compensated and decompensated cirrhosis as well as from 20 patients in hepatic and portal vein serum before and after the insertion of transjugular intrahepatic portosystemic stent (TIPS) using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Across all stages of liver disease, the gut-vascular barrier (GVB) marker plasmalemma vesicle protein-1 (PV-1) correlated with bacterial translocation markers endogenous endotoxin-core IgA antibodies (EndoCAb) and LPS-binding protein (LBP) but not with intestinal damage markers intestinal fatty acid binding protein (I-FABP) and zonulin-family peptides (ZFP). PV-1 and EndoCAb were higher in decompensated cirrhosis without further increase in ACLF. Among investigated markers, only I-FABP correlated with the portosystemic pressure gradient, and TIPS insertion significantly reduced portal concentrations within 24 h. Higher PV-1 levels indicated poor transplant-free survival in univariate and multivariable analysis.

CONCLUSIONS

Surrogate markers of bacterial gut barrier dysfunction and bacterial translocation like ZFP, LBP and EndoCAb appear of limited use in advanced stages of cirrhosis and are confounded by hepatic synthesis capacity, portal congestion and acute phase responses. The prognostic implications of circulating PV-1 in decompensated cirrhosis levels demand further investigation.

Reference intervals for serum immunoglobulin A, G, and M in a Danish paediatric population-based cohort

OBJECTIVES

To determine age- and sex-specific reference values for serum immunoglobulins (IgA, IgG, and IgM) in a population-based cohort of 6 to 18 years old Danish children and adolescents and investigate if immunoglobulin concentrations vary with body mass index standard deviation score (BMI SDS).

MATERIALS AND METHODS

A total of 2171 school children and adolescents (median age 12.0 years) were recruited. BMI SDS was calculated, and health status was assessed by questionnaire and blood samples. Fasting serum concentrations of IgA, IgG, and IgM were determined by immunonephelometry. Sex- and age-specific percentiles were generated and partitioned following the Clinical and Laboratory Standards Institute (CLSI) EP28-A3c guidelines. Multiple linear regression models were used to investigate associations betweenIgA, IgG, IgM, and BMI SDS adjusted for age and sex.

RESULTS

Concentrations of IgA increased with age but did not differ between boys and girls. An age-dependent increase was also detected for concentrations of IgG and IgM, although for IgG it was more pronounced in boys than girls. Girls had higher concentrations of IgG and IgM than boys at all ages. Concentrations of IgM were inversely associated with BMI SDS independent of age and sex.

CONCLUSIONS

We generated age- and sex-specific reference intervals for IgA, IgG, and IgM based on children and adolescents from a Danish/North-European Caucasian population-based cohort. The findings can help evaluate alterations seen in primary and secondary immunodeficiencies and autoimmune diseases.

Ellagic acid-protein nano-complex inhibits tumor growth by reducing the intratumor bacteria and inhibiting histamine production

In recent years, there has been growing interest in understanding the role of bacteria within tumors and their potential as targets for cancer therapy. In this work, we developed an ellagic acid (EA) - endogenous protein (eP) nanocomposite (eP-EA) to target tumors by EPR (enhanced permeability and retention), kill bacteria within tumors to regulate anti-tumor immune responses. The potential mechanism of eP-EA treatment is associated with the reduced abundance and diversity of microorganisms within the tumor, culminating with an altered metabolism within the Tumor microenvironment (TME). Among them, the metabolite histamine that contributes to tumor progression, is significantly reduced in the TME after eP-EA treatment. We show that one possible mechanism by which these microbes promote tumor growth is through the production of histamine. This work suggests that the ellagic acid (EA)-protein nano complex can enhance cancer immunotherapy by targeting the intratumoral bacteria and reduce their production of histamine, delineating the potential relationship between intratumor bacteria and their impact on tumors. Our work suggests that the EA-protein nano complex can enhance cancer immunotherapy by targeting the intratumoral bacteria, suggesting the role of bacterial metabolites in contributing to tumor progression.

Alcohol consumption does not influence SARS-CoV-2 vaccine immunogenicity: A stop the spread Ottawa cohort analysis

The effect of alcohol consumption on COVID-19 vaccine immunogenicity was evaluated. Participants from the Stop the Spread Ottawa cohort were categorized by alcohol consumption categorized as excessive or non-excessive based on the Canadian Centre on Substance Abuse and Addiction's (CCSA) 2023 guidelines on alcohol use. Our analyses showed that alcohol consumption did not influence SARS-CoV-2 antibody baseline levels, post vaccine increase or decay over time.

Beyond the Injury: How Does Smoking Impair Stem Cell-Mediated Repair Mechanisms? A Dual Review of Smoking-Induced Stem Cell Damage and Stem Cell-Based Therapeutic Applications

While the literature on molecular and clinical effects of smoking on the lungs and other organs has been expansively reviewed, there is no comprehensive compilation of the effects of smoking on stem cell (SC) populations. Recent research has shown that tobacco exposure severely compromises the function of SC populations, particularly those involved in tissue regeneration: mesenchymal SCs (MSCs), neural progenitors, and hematopoietic SCs. SC-based therapies have emerged as a promising approach to counteract smoking-related damage. In particular, MSCs have been extensively studied for their immunomodulatory properties, demonstrating the ability to repair damaged tissues, reduce inflammation, and slow disease progression in conditions such as chronic obstructive pulmonary disease. Combination therapies, which integrate pharmaceuticals with SC treatments, have shown potential in enhancing regenerative outcomes. This review examines the impact of smoking on SC biology, describes the processes impairing SC-mediated repair mechanisms and highlights recent advancements in SC-based therapies in the treatment of smoking-induced diseases. This review has two prongs: (1) it attempts to explain potential smoking-related disease etiology, and (2) it addresses a gap in the literature on SC-mediated repair mechanisms in chronic smokers.

Engineering FcRn binding kinetics dramatically extends antibody serum half-life and enhances therapeutic potential

BACKGROUND

Optimizing the IgG Fc domain for neonatal Fc receptor (FcRn) binding is crucial for enhancing antibody pharmacokinetics. The prolonged serum half-life of IgG antibody is governed by its pH-dependent interaction with FcRn, enabling efficient binding at acidic endosomal pH, intracellular trafficking, and release at neutral serum pH. However, a critical yet previously unrecognized challenge in Fc engineering for extending the serum half-life of therapeutic antibodies is the intense competition with endogenous IgG for FcRn binding during intracellular trafficking, which limits FcRn-mediated transport and reduces the serum persistence of therapeutic antibodies. To address this, we developed an Fc variant that precisely modulates pH-dependent FcRn binding kinetics, accelerates FcRn association at acidic pH, and promotes rapid dissociation at neutral pH, thereby enhancing FcRn-driven intracellular transport, outcompeting endogenous IgG, and achieving unprecedented improvement in the serum half-life of therapeutic antibodies.

RESULTS

Using comprehensive site-directed saturation mutagenesis coupled with functional screening, we generated a diverse panel of Fc variants and identified two with distinct FcRn binding kinetics: YML (L309Y/Q311M/M428L), which exhibited superior FcRn association at acidic pH and accelerated dissociation at neutral pH, and EML (L309E/Q311M/M428L), which displayed attenuated binding kinetics. In human FcRn transgenic mice, YML extended the serum half-life of clinically used trastuzumab with a wild-type Fc by 6.1-fold, demonstrating a remarkable improvement over previously reported Fc-engineered variants, including PFc29 (Q311R/M428L) and DHS (L309D/Q311H/N434S), which represent the most effective Fc modifications for prolonging serum persistence to date. This in vivo validation underscores the pivotal role of FcRn kinetic tuning in overcoming endogenous IgG competition and maximizing FcRn-mediated antibody transport. Additionally, YML exhibited potent complement-dependent cytotoxicity (CDC) while maintaining favorable physicochemical properties.

CONCLUSION

This study presents a rational Fc engineering framework to optimize FcRn binding kinetics, addressing a previously unconsidered challenge-endogenous IgG competition during intracellular trafficking of therapeutic antibodies. The distinct kinetic behaviors of YML and EML highlight the critical necessity of precise control over pH-dependent association and dissociation rates in FcRn binding. YML represents a next-generation Fc platform, offering enhanced pharmacokinetics and improved effector functions, thus providing a powerful strategy for developing biologics with superior serum persistence and therapeutic efficacy.

A genotype-phenotype transformer to assess and explain polygenic risk

Genome-wide association studies have linked millions of genetic variants to biomedical phenotypes, but their utility has been limited by lack of mechanistic understanding and widespread epistatic interactions. Recently, Transformer models have emerged as a powerful machine learning architecture with potential to address these and other challenges. Accordingly, here we introduce the Genotype-to-Phenotype Transformer (G2PT), a framework for modeling hierarchical information flow among variants, genes, multigenic systems, and phenotypes. As proof-of-concept, we use G2PT to model the genetics of TG/HDL (triglycerides to high-density lipoprotein cholesterol), an indicator of metabolic health. G2PT predicts this trait via attention to 1,395 variants underlying at least 20 systems, including immune response and cholesterol transport, with accuracy exceeding state-of-the-art. It implicates 40 epistatic interactions, including epistasis between APOA4 and CETP in phospholipid transfer, a target pathway for cholesterol modification. This work positions hierarchical graph transformers as a next-generation approach to polygenic risk.

Phosphonylated tyrosine and cysteine disulfide adducts both generated from immunoglobulin G and human serum albumin indicate exposure to the nerve agent VX in vitro

Pronase-catalyzed proteolysis is shown to produce single amino acid adducts of tyrosine (Tyr) and cysteine (Cys) obtained from both human serum albumin (HSA) and immunoglobulin G (IgG) after in vitro exposure of plasma to the nerve agent VX. Total plasma as well as isolated HSA and IgG yielded the Tyr residue phosphonylated with the ethyl methylphosphonic acid moiety, Tyr(-EMP). Furthermore, a Cys residue adducted with the diisopropylaminoethane thiol leaving group of the agent bound via a disulfide bridge, Cys(-DPAET), was also obtained from both proteins. Even though Tyr(-EMP) represents an internationally well-accepted biomarker of a VX-like agent its origin from plasma IgG has never been shown before. In addition, this is the first time that Cys(-DPAET) is presented as a biomarker of VX exposure clearly identifying the chemical nature of the V-type nerve agent's leaving group. Both biomarkers were detected after selective affinity-based solid-phase extraction (SPE) from plasma that yielded highly purified HSA and IgG as documented by sodium dodecyl polyamide gel electrophoresis (SDS-PAGE). Both biomarkers were found in the corresponding protein bands of HSA and IgG each after in-gel proteolysis with pronase. A micro liquid chromatography-electrospray ionization high-resolution tandem-mass spectrometry method (LC-ESI HR-MS/MS) was developed for the simultaneous detection of Tyr(-EMP) and Cys(-DPAET). The time for proteolysis was optimized for maximum biomarker yield. The method showed excellent selectivity and sensitivity, and the adducted proteins and biomarkers were found to be highly stable during storage. Accordingly, the presented method sheds more light on the molecular toxicology of VX and broadens the spectrum of methods suited for biomedical verification.

IgM has a better relative distribution in inflammation sites and tumor tissues than IgG

Immunoglobulins (Igs) play a crucial role in host's defense and in developing therapies against inflammatory diseases and cancer. Herein, we first studied the relative distribution of IgM and IgG in mouse models with acute or chronic inflammation. We found that IgM showed a more selective distribution towards inflammation sites than IgG. Similarly, in a tumor-bearing mouse model, IgM showed a higher tumor-to-blood or -to healthy organs ratio than IgG. We hypothesized that the difference in the sizes between IgM and IgG may have contributed to the differences in their relative distribution, which was supported by using an IgG nanoparticle system that was similar to IgM in size. To confirm the findings in clinics, we investigated IgM and IgG levels in the blood and bronchoalveolar lavage fluid (BALF) of patients diagnosed with fungal pneumonia and showed that the relative distribution of IgM was significantly higher than IgG in the BALF samples as compared to that in serum. Such an understanding of our immune system at the nano-level may help us develop more effective biotechnological interventions against inflammatory diseases and cancers.

Alcohol consumption and childhood trauma impact serum immunoglobulin levels in patients with alcohol use disorder

BACKGROUND

Alcohol Use Disorder (AUD) and childhood trauma both have detrimental effects on immune regulation. Immunoglobulins, key biomarkers of the adaptive immune system, may be selectively targeted by heavy alcohol consumption as well as childhood trauma. In this study, we investigated the relationship between alcohol drinking behavior, history of childhood trauma, and circulating levels of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) in individuals with AUD.

METHODS

Using linear regression, multiple variables, drinks per drinking day and childhood trauma questionnaire (CTQ) score, were evaluated in relation to immunoglobulin levels. All participants (N = 445) were treatment-seeking and admitted to the National Institutes of Health Clinical Center, where they underwent a battery of laboratory and psychological assessments.

RESULTS

Analyses showed a significant positive association between alcohol consumption and IgA. Furthermore, there was a significant negative association between childhood trauma and IgG. Other significant results include a negative association between substance use disorder diagnosis (other than alcohol) and IgA, while anxiety disorder diagnosis was associated with lower IgG.

CONCLUSION

Heavy alcohol drinking is associated with elevated IgA levels, which may be a potential risk factor for alcohol-associated liver disease. On the other hand, childhood trauma's association with decreased IgG levels may be indicative of broader immune dysfunction. Taken together, changes in immunoglobulins may be valuable markers linking alcohol consumption and childhood trauma to immune health and disease progression.

Serum proteomics reveals high-affinity and convergent antibodies by tracking SARS-CoV-2 hybrid immunity to emerging variants of concern

The rapid spread of SARS-CoV-2 and its continuing impact on human health has prompted the need for effective and rapid development of monoclonal antibody therapeutics. In this study, we investigate polyclonal antibodies in serum and B cells from the whole blood of three donors with SARS-CoV-2 immunity to find high-affinity anti-SARS-CoV-2 antibodies to escape variants. Serum IgG antibodies were selected by their affinity to the receptor-binding domain (RBD) and non-RBD sites on the spike protein of Omicron subvariant B.1.1.529 from each donor. Antibodies were analyzed by bottom-up mass spectrometry, and matched to single- and bulk-cell sequenced repertoires for each donor. The antibodies observed in serum were recombinantly expressed, and characterized to assess domain binding, cross-reactivity between different variants, and capacity to inhibit RBD binding to host protein. Donors infected with early Omicron subvariants had serum antibodies with subnanomolar affinity to RBD that also showed binding activity to a newer Omicron subvariant BQ.1.1. The donors also showed a convergent immune response. Serum antibodies and other single- and bulk-cell sequences were similar to publicly reported anti-SARS-CoV-2 antibodies, and the characterized serum antibodies had the same variant-binding and neutralization profiles as their reported public sequences. The serum antibodies analyzed were a subset of anti-SARS-CoV-2 antibodies in the B cell repertoire, which demonstrates significant dynamics between the B cells and circulating antibodies in peripheral blood.

Comparative Assessment of Acute Pulmonary Effects Induced by Heat-Not-Burn Tobacco Aerosol Inhalation in a Murine Model

Tobacco smoking remains a major global health concern, causing preventable deaths and economic strain. Although new tobacco products such as heat-not-burn (HnB) are safer alternatives to traditional cigarettes, research on their associated risks remains limited. This study aimed to investigate the effects of HnB smoke exposure on the lungs compared to those of traditional cigarettes and the combined use of HnB and cigarettes using experiments with a mouse model. We quantitatively analyzed changes in the levels of 92 blood plasma proteins using the proximity extension assay method and observed significant changes in their levels in mice exposed to different smoke conditions; specifically, the levels of certain proteins, including Ccl20, Cxcl1, and Pdgfb, increased in the HnB smoke-exposed group, suggesting activation of nicotine pathways. Comparative analysis with traditional cigarette smoke-exposed mice further highlighted similarities and differences in their protein expression profiles. This study contributes to an improved understanding of the biological mechanisms underlying the harmful effects of alternative nicotine delivery systems and identifies potential biomarkers associated with the harmful effects of HnB smoke exposure. However, the precise impact of nicotine on the immune system may be influenced by various factors, necessitating further research.

Dietary supplementation with compound microecological preparations: effects on the production performance and gut microbiota of lactating female rabbits and their litters

Early weaning is frequently accompanied by a significant increase in diarrhea and mortality rates, which reduces rabbits' performance. Although antibiotics can reduce pathogenic bacteria, they also harm beneficial microorganisms and disrupt the normal intestinal microbiota balance. In order to find non-residue and non-toxic alternatives to antibiotics to ensure the safety of animal products, we conducted a study on the effect of compound microecological preparations supplementation on lactating female rabbits and their offspring. A total of 60 female rabbits were randomly assigned to four groups: CON, supplemented with probiotics at 3, 6, and 9 g/female rabbit/day from day 24 of gestation until weaning. We observed that probiotics supplementation significantly enhanced production performance (P < 0.05), immune and antioxidant function (P < 0.05), as well as intestinal flora composition in lactating rabbits and their offspring. Notably, compared with the control group, the experimental group exhibited a 19.23%, 44.22%, and 24.57% increase in milk yield (P = 0.002). Regarding rabbit growth performance, the average body weight of young rabbits in the experimental group showed a significant increase of 3.59%, 10.22%, and 6.74% at day 35 (P = 0.022), whereas the average daily gain (ADG) of rabbits aged between 21 and 35 days was significantly elevated by 4.94%, 17.06%, and 6.28% in the experimental group (P < 0.001). In conclusion, probiotics supplementation can significantly enhance lactation performance, promote growth and disease resistance in rabbits, as well as improve intestinal health when administered at a dosage of 6 g/day. Moreover, the limited sample size in this study may hinder the detection of subtle effects, and augmenting the sample size will bolster the reliability of the study findings.

IMPORTANCE

The intestinal environment of rabbits is fragile and susceptible to environmental influences, leading to inflammatory intestinal diseases. Adding antibiotics to rabbit feed can achieve the effect of preventing and treating inflammation, which can also lead to the imbalance of the gut microbiota and residual antibiotics in agricultural products. Composite probiotics are live microbial feed additives composed of various ratios of probiotics and have become the most promising alternative to antibiotics due to their residue-free and non-toxic properties. The aim of this study was to investigate the impact of compound probiotics on lactating female rabbits and their offspring. Our findings highlight the potential of compound microecological preparations as an effective strategy for enhancing lactation performance, immune function, and antioxidant capacity in rabbits. The supplementation of probiotics through rabbit milk offers a promising approach to optimize the growth and health outcomes of newborn rabbits.

Identification of plasma proteins binding oxidized phospholipids using pull-down proteomics and OxLDL masking assay

Oxidized phospholipids (OxPLs) are increasingly recognized as toxic and proinflammatory mediators, which raises interest in the mechanisms of their detoxification. Circulating OxPLs are bound and neutralized by plasma proteins, including both antibodies and non-immunoglobulin proteins. The latter group of proteins is essentially not investigated because only three OxPC-binding plasma proteins are currently known. The goal of this work was to characterize a broad spectrum of plasma proteins selectively binding OxPLs. Using pull-down-proteomic analysis, we found about 150 non-immunoglobulin proteins preferentially binding oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylcholine (OxPAPC) as compared to non-oxidized PAPC. To test if candidate proteins indeed can form a barrier isolating OxPLs from recognition by other proteins, we applied an immune masking assay. Oxidized LDL (OxLDL) immobilized in multiwell plates was used as a carrier of OxPLs, while mAbs recognizing OxPC or OxPE were used as "detectors" showing if OxPLs on the surface of OxLDL are physically accessible to external binding partners. Using an orthogonal combination of pull-down and masking assays we confirmed that previously described OxPL-binding proteins (non-fractionated IgM, CFH, and Apo-M) indeed can bind to and mask OxPC and OxPE on liposomes and OxLDL. Furthermore, we identified additional plasma proteins selectively binding and masking OxPC including Apo-D, Apo-H, pulmonary surfactant-associated protein B, and antithrombin-III. We hypothesize that in addition to circulating antibodies, multiple non-immunoglobulin plasma proteins can also bind OxPLs and modulate their recognition by innate and adaptive immunity.

Biochemical and biophysical mechanisms macrophages use to tune phagocytic appetite

Macrophages phagocytose, or eat, pathogens, dead cells and cancer cells. To activate phagocytosis, macrophages recognize 'eat me' signals like IgG and phosphatidylserine on the target cell surface. Macrophages must carefully adjust their phagocytic appetite to ignore non-specific or transient eat me signal exposure on healthy cells while still rapidly recognizing pathogens and debris. Depending on the context, macrophages can increase their appetite for phagocytosis, to prioritize an effective immune response, or decrease their appetite, to avoid damage to healthy tissue during homeostasis. In this Review, we discuss the biochemical and biophysical mechanisms that macrophages employ to increase or decrease their sensitivity or capacity for phagocytosis. We discuss evidence that macrophages tune their sensitivity via several mechanisms, including altering the balance of activating and inhibitory receptor expression, altering the availability of activating receptors, as well as influencing their clustering and mobility, and modulating inhibitory receptor location. We also highlight how membrane availability limits the capacity of macrophages for phagocytosis and discuss potential mechanisms to promote membrane recycling and increase phagocytic capacity. Overall, this Review highlights recent work detailing the molecular toolkit that macrophages use to alter their appetite.

Urban wastewater contains a functional human antibody repertoire of mucosal origin

Wastewater-based surveillance of human disease offers timely insights to public health, helping to mitigate infectious disease outbreaks and decrease downstream morbidity and mortality. These systems rely on nucleic acid amplification tests for monitoring disease trends, while antibody-based seroprevalence surveys gauge community immunity. However, serological surveys are resource-intensive and subject to potentially long lead times and sampling bias. We identified and characterized a human antibody repertoire, predominantly secretory IgA, isolated from a central wastewater treatment plant and building-scale wastewater collection points. These antibodies partition to the solids fraction and retain immunoaffinity for SARS-CoV-2 and Influenza A virus antigens. This stable pool could enable real-time tracking for correlates of vaccination, infection, and immunity, aiding in establishing population-level thresholds for immune protection and assessing the efficacy of future vaccine campaigns.

Comparative study of trastuzumab modification analysis using mono/multi-epitope affinity technology with LC-QTOF-MS

Dynamic tracking analysis of monoclonal antibodies (mAbs) biotransformation in vivo is crucial, as certain modifications could inactivate the protein and reduce drug efficacy. However, a particular challenge (i.e. immune recognition deficiencies) in biotransformation studies may arise when modifications occur at the paratope recognized by the antigen. To address this limitation, a multi-epitope affinity technology utilizing the metal organic framework (MOF)@Au@peptide@aptamer composite material was proposed and developed by simultaneously immobilizing complementarity determining region (CDR) mimotope peptide (HH24) and non-CDR mimotope aptamer (CH1S-6T) onto the surface of MOF@Au nanocomposite. Comparative studies demonstrated that MOF@Au@peptide@aptamer exhibited significantly enhanced enrichment capabilities for trastuzumab variants in comparison to mono-epitope affinity technology. Moreover, the higher deamidation ratio for LC-Asn-30 and isomerization ratio for HC-Asn-55 can only be monitored by the novel bioanalytical platform based on MOF@Au@peptide@aptamer and liquid chromatography-quadrupole time of flight-mass spectrometry (LC-QTOF-MS). Therefore, multi-epitope affinity technology could effectively overcome the biases of traditional affinity materials for key sites modification analysis of mAb. Particularly, the novel bioanalytical platform can be successfully used for the tracking analysis of trastuzumab modifications in different biological fluids. Compared to the spiked phosphate buffer (PB) model, faster modification trends were monitored in the spiked serum and patients' sera due to the catalytic effect of plasma proteins and relevant proteases. Differences in peptide modification levels of trastuzumab in patients' sera were also monitored. In summary, the novel bioanalytical platform based on the multi-epitope affinity technology holds great potentials for in vivo biotransformation analysis of mAb, contributing to improved understanding and paving the way for future research and clinical applications.

Regulators of placental antibody transfer through a modeling lens

Infants are vulnerable to infections owing to a limited ability to mount a humoral immune response and their tolerogenic immune phenotype, which has impeded the success of newborn vaccination. Transplacental transfer of IgG from mother to fetus provides crucial protection in the first weeks of life, and maternal immunization has recently been implemented as a public health strategy to protect newborns against serious infections. Despite their early success, current maternal vaccines do not provide comparable protection across pregnancies with varying gestational lengths and placental and maternal immune features, and they do not account for the dynamic interplay between the maternal immune response and placental transfer. Moreover, progress toward the rational design of maternal vaccines has been hindered by inadequacies of existing experimental models and safety challenges of investigating longitudinal dynamics of IgG transfer in pregnant humans. Alternatively, in silico mechanistic models are a logical framework to disentangle the processes regulating placental antibody transfer. This Review synthesizes current literature through a mechanistic modeling lens to identify placental and maternal regulators of antibody transfer, their clinical covariates, and knowledge gaps to guide future research. We also describe opportunities to use integrated modeling and experimental approaches toward the rational design of vaccines against existing and emerging neonatal pathogen threats.

Salivary diagnostics: opportunities and challenges

Saliva contains a diverse array of biomarkers indicative of various diseases. Saliva testing has been a major advancement towards non-invasive point-of-care diagnosis with clinical significance. However, there are challenges associated with salivary diagnosis from sample treatment and standardization. This review highlights the biomarkers in saliva and their role in identifying relevant diseases. It provides an overview and discussion about the current practice of saliva collection and processing, and advancements in saliva detection systems from in vitro methods to wearable oral devices. The review also addresses challenges in saliva diagnostics and proposes solutions, aiming to offer a comprehensive understanding and practical guidance for improving saliva-based detection in clinical diagnosis. Saliva diagnosis provides a rapid, effective, and safe alternative to traditional blood and urine tests for screening large populations and enhancing infectious disease diagnosis and surveillance. It meets the needs of various fields such as disease management, drug screening, and personalized healthcare with advances in saliva detection systems offering high sensitivity, fast response times, portability, and automation. Standardization of saliva collection, treatment, biomarker discovery, and detection between different laboratories needs to be implemented to obtain reliable salivary diagnosis in clinical practice.

IgG4 serologic elevation in a patient with severe hidradenitis suppurativa: a case report and review of the literature

Hidradenitis suppurativa (HS) is a chronic cutaneous and systemic inflammatory condition. Increasingly, reports have found that immunoglobulins play a role in the exaggerated immune response occurring in severe HS. It is important to recognize these implications as HS patients may present with laboratory abnormalities relating to chronic inflammation and immune activation. If these laboratory abnormalities are mistakenly associated with another disease process, it could lead to invasive workup and treatment, causing harm to patients. We describe the case of a 23-year-old woman with Hurley stage III HS who was hospitalized and found to have persistent immunoglobulin-G4 (IgG4) elevation. Upon discharge, the patient was diagnosed with IgG4-related disease (IgG4-RD) and started treatment with azathioprine. However, the biopsy ultimately was negative for IgG4-RD, and she presented to our clinic several months later with worsening HS disease during an active flare. Physical examination revealed actively draining nodules and sinus tracts in the bilateral axillae, inguinal folds, and mons pubis region. A confusing laboratory marker with HS was observed in this case. IgG4 has the potential to inhibit or activate inflammation depending on the context, and so IgG4 elevation has been noted in varying disease states. IgG4 elevation is observed in chronic inflammatory states and may represent a compensatory response by the body. While no other cases have reported the association between HS and IgG4 elevation, IgG levels have been found to reflect HS disease severity. Therefore, IgG4 could play a potential role in HS disease monitoring, and awareness of this association is important for providers when managing patients with HS.

FcRider: a recombinant Fc nanoparticle with endogenous adjuvant activities for hybrid immunization

Active immunization (vaccination) induces long-lasting immunity with memory, which takes weeks to months to develop. Passive immunization (transfer of neutralizing antibodies) provides immediate protection, yet with high cost and effects being comparatively short-lived. No currently approved adjuvants are compatible with formulations to combine active and passive immunizations, not to mention their huge disparities in administration routes and dosage. To solve this, we engineered the Fc fragment of human IgG1 into a hexamer nanoparticle and expressed its afucosylated form in Fut8-/- CHO cells, naming it "FcRider." FcRider is highly soluble with long-term stability, easily produced at high levels equivalent to those of therapeutic antibodies, and is amenable to conventional antibody purification schemes. Most importantly, FcRider possesses endogenous adjuvant activities. Using SWHEL B cell receptor (BCR) transgenic mice, we found that HEL-FcRider induced GL7+ germinal center B cells and HEL-specific IgG. Similarly, immunizing mice with UFO-BG-FcRider, a fusion containing the stabilized human immunodeficiency virus-1 (HIV-1) Env protein as immunogen, promoted somatic hypermutation and generation of long CDR3 of the IgG heavy chains. Intramuscular injection of (Fba + Met6)3-FcRider, a fusion with two peptide epitopes from Candida albicans cell surface, stimulated strong antigen-specific IgG titers. In three different models, we showed that afucosylated FcRider functions as a multivalent immunogen displayer and stimulates antigen-specific B cells without any exogenous adjuvant. As an antibody derivative, afucosylated FcRider could be a novel platform combining vaccines and therapeutic antibodies, integrating active and passive immunizations into single-modality "hybrid immunization" to provide complete and long-lasting protection against infections, and may open new avenues in cancer immunotherapy as well.

Viral antibody response predicts morbidity and mortality in alcohol-associated hepatitis

BACKGROUND AND AIMS

Alcohol-associated hepatitis (AH) is associated with very high mortality despite abstinence from alcohol; up to 40% of patients die within 6 months of diagnosis. Patients with AH are especially prone to infections, which can lead to multiorgan dysfunction and poorer prognosis.

APPROACH AND RESULTS

We performed comprehensive serological profiling of the viral and bacterial infection history of 36 healthy controls, 48 patients with alcohol use disorder, and 224 patients with AH from 2 multicenter observational studies. We used systematic viral and bacterial epitope scanning by VirScan, a phage-display immunoprecipitation and sequencing technology that detects the peptides recognized by antibodies in patient sera, to comprehensively analyze antiviral and antibacterial antibodies and identify serologic biomarkers to predict patient outcomes. We found significant differences in the serological profiles of the 3 populations. The number of serum antibody epitopes in patients with alcohol use disorder during abstinence was increased compared with during active alcohol use. A decreased number and diversity of viral and bacterial antibody targets were detected in the sera of patients with AH, particularly those with a higher Child-Pugh score. In patients with AH, a decrease in the serum antiviral, but not antibacterial, antibody repertoire was associated with decompensation and mortality. Ninety-day mortality in AH could be predicted using a serum viral epitope signature.

CONCLUSIONS

Abstinence from alcohol is associated with a significant increase in serum viral and bacterial antibody response. Decreased serum antiviral antibody repertoire is predictive of decompensation of liver disease and mortality in patients with AH.

Hybrid Integration of Wearable Devices for Physiological Monitoring

Wearable devices can provide timely, user-friendly, non- or minimally invasive, and continuous monitoring of human health. Recently, multidisciplinary scientific communities have made significant progress regarding fully integrated wearable devices such as sweat wearable sensors, saliva sensors, and wound sensors. However, the translation of these wearables into markets has been slow due to several reasons associated with the poor system-level performance of integrated wearables. The wearability consideration for wearable devices compromises many properties of the wearables. Besides, the limited power capacity of wearables hinders continuous monitoring for extended duration. Furthermore, peak-power operations for intensive computations can quickly create thermal issues in the compact form factor that interfere with wearability and sensor operations. Moreover, wearable devices are constantly subjected to environmental, mechanical, chemical, and electrical interferences and variables that can invalidate the collected data. This generates the need for sophisticated data analytics to contextually identify, include, and exclude data points per multisensor fusion to enable accurate data interpretation. This review synthesizes the challenges surrounding the wearable device integration from three aspects in terms of hardware, energy, and data, focuses on a discussion about hybrid integration of wearable devices, and seeks to provide comprehensive guidance for designing fully functional and stable wearable devices.

Exploring Total Immunoglobulin A's Impact on Non-Biopsy Diagnosis of Celiac Disease: Implications for Diagnostic Accuracy

OBJECTIVE

In the current debate surrounding the biopsy-free diagnosis of CeD, it is crucial to identify factors influencing the accuracy of results. This study investigated the impact of total IgA on the non-invasive diagnosis of celiac disease (CeD).

METHODS

We retrospectively assessed total IgA titers' influence on the diagnostic accuracy of different tTG-IgA thresholds compared to the upper reference value (UNL).

RESULTS

Of 165 included patients, tTG-IgA values at 10× UNL and 6× UNL showed specificity of 82.6% and 73.9% and sensitivity of 49.3% and 69.0%, respectively, in predicting intestinal villous atrophy (Marsh 3). In 130 patients, total IgA levels were known at baseline. These patients were divided into three tertiles according to total IgA, i.e., patients with lower, intermediate, or higher total IgA within the population. For patients with total IgA ≥ 245 mg/dL, using a tTG-IgA cutoff of 6× UNL instead of 10× UNL resulted in decreased specificity from 71.4% to 42.8% and increased sensitivity from 67.6% to 81.1%. For patients with total IgA < 174 mg/dL and between 174 mg/dL and 245 mg/dL, using a tTG-IgA cutoff of 6× UNL instead of 10× UNL maintained specificity (75.0% and 85.7%, respectively) with increased sensitivity (from 46.2% to 64.1% and from 36.1% to 52.8%, respectively).

CONCLUSIONS

In conclusion, total IgA influences the diagnostic accuracy of a predetermined tTG-IgA cutoff. Greater consideration should be given to total IgA, beyond its deficiency, in evaluating the applicability and accuracy of non-invasive CeD diagnosis.

Serum immunoglobulin levels in group E of chronic obstructive pulmonary disease: insights for clinical management and immunoglobulin therapy strategies

OBJECTIVE

The study aimed to characterize serum immunoglobulin (Ig) concentrations and their relationship with clinical and paraclinical features in patients with COPD group E in the stable stage. Additionally, the study focused on evaluating the relationship between serum Ig levels and the risk of exacerbations over the next 12 months, thereby clarifying the role of serum Ig deficiency in affecting the future risk for these patients.

METHODS

A prospective observational study assessed IgG, IgA, IgM, and IgE levels in 67 COPD patients and 30 healthy controls at Military Hospital 103 from October 2017 to August 2020. Primary outcomes included Ig isotype levels in COPD patients, with secondary outcomes exploring differences compared to controls and associations with clinical variables.

RESULTS

COPD patients showed significantly lower IgG concentrations and higher IgA levels than controls. IgM and IgE levels did not differ significantly. Subgroup analysis revealed notable decreases in IgG1 and IgG3 concentrations, with 10.4% of patients exhibiting reduced IgG levels and 0.3% diagnosed with common variable immunodeficiency. No significant associations were found between Ig levels and exacerbation risk or clinical variables.

CONCLUSIONS

Serum IgG and IgM concentrations were significantly reduced in COPD patients compared to normal individuals, with IgG1 and IgG3 concentrations notably low. Serum IgA levels were significantly higher in COPD patients compared with normal controls. However, no significant association was found between Ig concentrations, particularly serum IgG deficiency and its subclasses, with the frequency and risk of exacerbations during 12 months of longitudinal follow-up. Caution is warranted in the use of immunoglobulin therapy in the treatment of COPD patients.

TRIAL REGISTRATION

An independent ethics committee approved the study (Ethics Committee of Military Hospital 103 (No. 57/2014/VMMU-IRB), which was performed in accordance with the Declaration of Helsinki, Guidelines for Good Clinical Practice.

Hypogammaglobulinaemia during rituximab treatment in multiple sclerosis: A Swedish cohort study

BACKGROUND AND PURPOSE

Mechanisms behind hypogammaglobulinaemia during rituximab treatment are poorly understood.

METHODS

In this register-based multi-centre retrospective cohort study of multiple sclerosis (MS) patients in Sweden, 2745 patients from six participating Swedish MS centres were identified via the Swedish MS registry and included between 14 March 2008 and 25 January 2021. The exposure was treatment with at least one dose of rituximab for MS or clinically isolated syndrome, including data on treatment duration and doses. The degree of yearly decrease in immunoglobulin G (IgG) and immunoglobulin M (IgM) levels was evaluated.

RESULTS

The mean decrease in IgG was 0.27 (95% confidence interval 0.17-0.36) g/L per year on rituximab treatment, slightly less in older patients, and without significant difference between sexes. IgG or IgM below the lower limit of normal (<6.7 or <0.27 g/L) was observed in 8.8% and 8.3% of patients, respectively, as nadir measurements. Six out of 2745 patients (0.2%) developed severe hypogammaglobulinaemia (IgG below 4.0 g/L) during the study period. Time on rituximab and accumulated dose were the main predictors for IgG decrease. Previous treatment with fingolimod and natalizumab, but not teriflunomide, dimethyl fumarate, interferons or glatiramer acetate, were significantly associated with lower baseline IgG levels by 0.80-1.03 g/L, compared with treatment-naïve patients. Switching from dimethyl fumarate or interferons was associated with an additional IgG decline of 0.14-0.19 g/L per year, compared to untreated.

CONCLUSIONS

Accumulated dose and time on rituximab treatment are associated with a modest but significant decline in immunoglobulin levels. Previous MS therapies may influence additional IgG decline.

Serum immunoglobulin concentrations and risk of type 2 diabetes mellitus in adults: a prospective cohort study from the TCLSIH study

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by hyperglycemia resulting from defects in insulin secretion and/or insulin action. Increasing evidence suggests that inflammation played an important role in the pathogenesis of T2DM. Prospective studies on the link between immunoglobulins concentrations and the risk of T2DM in adults are limited. We developed a cohort study including 7,093 adults without T2DM history. The incidence of T2DM was 16.45 per 1,000 person-years. Compared with the lowest quartiles, the hazard ratios (95% confidence intervals) of T2DM for the highest quartiles of IgG, IgE, IgM and IgA were 0.64 (0.48-0.85), 0.94 (0.72-1.23), 0.68 (0.50-0.92) and 1.62 (1.24-2.11) (P for trend was < 0.01, 0.84, 0.02 and < 0.0001), respectively, suggesting that serum IgG and IgM concentrations were inversely associated with the incidence of T2DM, and IgA levels were positively associated with the risk of T2DM in a general adult population.

Antibody-Driven Assembly of Plasmonic Core-Satellites to Increase the Sensitivity of a SERS Vertical Flow Immunoassay

Here, we describe a SERS-based vertical flow assay as a platform technology suitable for point-of-care (POC) diagnostic testing. A capture substrate is constructed from filter paper embedded with spherical gold nanoparticles (AuNPs) and functionalized with an appropriate capture antibody. The capture substrate is loaded into a filtration device and connected to a syringe to rapidly and repeatedly pass the sample through the sensor for efficient antigen binding. The antigen is then labeled with a SERS-active detection probe. We show that only a few Raman reporter molecules, exclusively located adjacent to the plasmonic capture substrate, generate detectible signals. To maximize the signal from underutilized Raman reporter molecules, we employ a secondary signal enhancing probe that undergoes antibody-directed assembly to form plasmonic core-satellites. This facile enhancement step provides a 3.5-fold increase in the signal and a detection limit of 0.23 ng/mL (1.6 pM) for human IgG. This work highlights the potential to rationally design plasmonic architectures using widely available and reproducible spherical AuNPs to achieve large SERS enhancements for highly sensitive POC diagnostics.

Antibody-drug conjugate adverse effects can be understood and addressed based on immune complex clearance mechanisms

ABSTRACT

Numerous antibody-drug conjugates (ADCs) are being developed for cancer immunotherapy. Although several of these agents have demonstrated considerable clinical efficacy and have won Food and Drug Administration (FDA) approval, in many instances, they have been characterized by adverse side effects (ASEs), which can be quite severe in a fraction of treated patients. The key hypothesis in this perspective is that many of the most serious ASEs associated with the use of ADCs in the treatment of cancer can be most readily explained and understood due to the inappropriate processing of these ADCs via pathways normally followed for immune complex clearance, which include phagocytosis and trogocytosis. We review the key published basic science experiments and clinical observations that support this idea. We propose that it is the interaction of the ADC with Fcγ receptors expressed on off-target cells and tissues that can most readily explain ADC-mediated pathologies, which therefore provides a rationale for the design of protocols to minimize ASEs. We describe measurements that should help identify those patients most likely to experience ASE due to ADC, and we propose readily available treatments as well as therapies under development for other indications that should substantially reduce ASE associated with ADC. Our focus will be on the following FDA-approved ADC for which there are substantial literatures: gemtuzumab ozogamicin and inotuzumab ozogamicin; and trastuzumab emtansine and trastuzumab deruxtecan.

Lupus IgA1 autoantibodies synergize with IgG to enhance plasmacytoid dendritic cell responses to RNA-containing immune complexes

Autoantibodies to nuclear antigens are hallmarks of systemic lupus erythematosus (SLE) where they contribute to pathogenesis. However, there remains a gap in our knowledge regarding how different isotypes of autoantibodies contribute to this autoimmune disease, including the production of the critical type I interferon (IFN) cytokines by plasmacytoid dendritic cells (pDCs) in response to immune complexes (ICs). We focused on IgA, which is the second-most prevalent isotype in serum and, along with IgG, is deposited in glomeruli in individuals with lupus nephritis. We show that individuals with SLE have serum IgA autoantibodies against most nuclear antigens, correlating with IgG against the same antigen. We investigated whether IgA autoantibodies against a major SLE autoantigen, Smith ribonucleoprotein (Sm/RNP), played a role in IC activation of pDCs. We found that pDCs expressed the IgA-specific Fc receptor, FcαR, and IgA1 autoantibodies synergized with IgG in RNA-containing ICs to generate robust primary blood pDC IFN-α responses in vitro. pDC responses to these ICs required both FcαR and FcγRIIa, showing synergy between these Fc receptors. Sm/RNP IC binding to and internalization by pDCs were greater when ICs contained both IgA1 and IgG. Circulating pDCs from individuals with SLE had higher binding of IgA1-containing ICs and higher expression of FcαR than pDCs from healthy control individuals. Although pDC FcαR expression correlated with the blood IFN-stimulated gene signature in SLE, Toll-like receptor 7 agonists, but not IFN-α, up-regulated pDC FcαR expression in vitro. Together, we show a mechanism by which IgA1 autoantibodies contribute to SLE pathogenesis.

LiFT (a Lithium Fiber-Based Test): An At-Home Companion Diagnostics for a Safer Lithium Therapy in Bipolar Disorder

This work presents LiFT (a lithium fiber-based test), a low-cost electrochemical sensor that can measure lithium in human saliva and urine with FDA-required accuracy. Lithium is used for the treatment of bipolar disorder, and has a narrow therapeutic window. Close monitoring of lithium concentration in biofluids and adjustment of drug dosage can minimize the devastating side effects. LiFT is an inexpensive, yet accurate and simple-to-operate lithium sensor for frequent at-home testing for early identification of lithium toxicity. The low cost and high accuracy of LiFT are enabled through an innovative design and the use of ubiquitous materials such as yarn and carbon black for fabrication. LiFT measures Li+ through potentiometric recognition using a lithium selective sensing membrane that is deposited on the ink-coated yarn. A detection limit of 0.97 µM is obtained with a sensitivity of 59.07±1.25 mV/decade for the Li+ sensor in deionized water. Moreover, the sodium correction extended LiFT's linear range in urine and saliva to 0.5 mM. The LiFT platform sends the test results to the patient's smartphone, which subsequently can be shared with the patient's healthcare provider to expedite diagnosis and prevention of acute lithium toxicity.

Harnessing Bioluminescent Bacteria to Develop an Enzymatic-free Enzyme-linked immunosorbent assay for the Detection of Clinically Relevant Biomarkers

Enzyme-linked immunosorbent assay (ELISA) is the gold standard technique for measuring protein biomarkers due to its high sensitivity, specificity, and throughput. Despite its success, continuous advancements in ELISA and immunoassay formats are crucial to meet evolving global challenges and to address new analytical needs in diverse applications. To expand the capabilities and applications of immunoassays, we introduce a novel ELISA-like assay that we call Bioluminescent-bacteria-linked immunosorbent assay (BBLISA). BBLISA is an enzyme-free assay that utilizes the inner filter effect between the bioluminescent bacteriaAllivibrio fischeriand metallic nanoparticles (gold nanoparticles and gold iridium oxide nanoflowers) as molecular absorbers. Functionalizing these nanoparticles with antibodies induces their accumulation in wells upon binding to molecular targets, forming the classical immune-sandwich complex. Thanks to their ability to adsorb the light emitted by the bacteria, the nanoparticles can suppress the bioluminescence signal, allowing the rapid quantification of the target. To demonstrate the bioanalytical properties of the novel immunoassay platform, as a proof of principle, we detected two clinically relevant biomarkers (human immunoglobulin G and SARS-CoV-2 nucleoprotein) in human serum, achieving the same sensitivity and precision as the classic ELISA. We believe that BBLISA can be a promising alternative to the standard ELISA techniques, offering potential advancements in biomarker detection and analysis by combining nanomaterials with a low-cost, portable bioluminescent platform.

Vaccine-Boosted CCP Decreases Virus Replication and Hastens Resolution of Infection Despite Transiently Enhancing Disease in SARS-CoV-2-Infected Hamsters

Definitive data demonstrating the utility of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) for treating immunocompromised patients remains elusive. To better understand the mechanism of action of CCP, we studied viral replication and disease progression in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected hamsters treated with CCP obtained from recovered COVID-19 patients that were also vaccinated with an mRNA vaccine, hereafter referred to as Vaxplas. Vaxplas transiently enhanced disease severity and lung pathology in hamsters treated near peak viral replication due to immune complex and activated complement deposition in pulmonary endothelium, and recruitment of M1 proinflammatory macrophages into the lung parenchyma. However, aside from one report, transient enhanced disease has not been reported in CCP recipient patients, and the transient enhanced disease in Vaxplas hamsters may have been due to mismatched species IgG-FcR interactions, infusion timing, or other experimental factors. Despite transient disease enhancement, Vaxplas dramatically reduced virus replication in lungs and improved infection outcome in SARS-CoV-2-infected hamsters.

Simultaneous quantification of co-administered trastuzumab and pertuzumab in serum based on nano-surface and molecular-orientation limited (nSMOL) proteolysis

Monoclonal antibodies (mAbs) are pivotal therapeutic agents for various diseases, and effective treatment hinges on attaining a specific threshold concentration of mAbs in patients. With the rising adoption of combination therapy involving multiple mAbs, there arises a clinical demand for multiplexing assays capable of measuring the concentrations of these mAbs. However, minimizing the complexity of serum samples while achieving rapid and accurate quantification is difficult. In this work, we introduced a novel method termed nano-surface and molecular orientation limited (nSMOL) proteolysis for the fragment of antigen binding (Fab) region-selective proteolysis of co-administered trastuzumab and pertuzumab based on the pore size difference between the protease nanoparticles (∼200 nm) and the resin-captured antibody (∼100 nm). The hydrolyzed peptide fragments were then quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this process, the digestion time is shortened, and the produced digestive peptides are greatly reduced, thereby minimizing sample complexity and increasing detection accuracy. Assay linearity was confirmed within the ranges of 0.200-200 μg mL-1 for trastuzumab and 0.300-200 μg mL-1 for pertuzumab. The intra- and inter-day precision was within 9.52% and 8.32%, except for 12.5% and 10.8% for the lower limit of quantitation, and the accuracy (bias%) was within 6.3%. Additionally, other validation parameters were evaluated, and all the results met the acceptance criteria of the guiding principles. Our method demonstrated accuracy and selectivity for the simultaneous determination of trastuzumab and pertuzumab in clinical samples, addressing the limitation of ligand binding assays incapable of simultaneously quantifying mAbs targeting the same receptor. This proposed assay provides a promising technical approach for realizing clinical individualized precise treatment, especially for co-administered mAbs.

Quantum Dot-Fab' Conjugates as Compact Immunolabels for Microtubule Imaging and Cell Classification

Antibodies and their conjugates of fluorescent labels are widely applied in life sciences research and clinical pathology. Among diverse label types, compact quantum dots (QDs) provide advantages of multispectral multiplexing, bright signals in the deep red and infrared, and low steric hindrance. However, QD-antibody conjugates have random orientation of the antigen-binding domain which may interfere with labeling and are large (20-30 nm) and heterogeneous, which limits penetration into biospecimens. Here, we develop conjugates of compact QDs and Fab' antibody fragments as primary immunolabels. Fab' fragments are conjugated site-specifically through sulfhydryl groups distal to antigen-binding domains, and the multivalent conjugates have small and homogeneous sizes (∼12 nm) near those of full-sized antibodies. Their performance as immunolabels for intracellular antigens is evaluated quantitatively by metrics of microtubule labeling density and connectivity in fixed cells and for cytological identification in fixed brain specimens, comparing results with probes based on spectrally-matched dyes. QD-Fab' conjugates outperformed QD conjugates of full-sized antibodies and could be imaged with bright signals with 1-photon and 2-photon excitation. The results demonstrate a requirement for smaller bioaffinity agents and site-specific orientation for the success of nanomaterial-based labels to enhance penetration in biospecimens and minimize nonspecific staining.

KSHV infection of B cells primes protective T cell responses in humanized mice

Kaposi sarcoma associated herpesvirus (KSHV) is associated with around 1% of all human tumors, including the B cell malignancy primary effusion lymphoma (PEL), in which co-infection with the Epstein Barr virus (EBV) can almost always be found in malignant cells. Here, we demonstrate that KSHV/EBV co-infection of mice with reconstituted human immune systems (humanized mice) leads to IgM responses against both latent and lytic KSHV antigens, and expansion of central and effector memory CD4+ and CD8+ T cells. Among these, KSHV/EBV dual-infection allows for the priming of CD8+ T cells that are specific for the lytic KSHV antigen K6 and able to kill KSHV/EBV infected B cells. This suggests that K6 may represent a vaccine antigen for the control of KSHV and its associated pathologies in high seroprevalence regions, such as Sub-Saharan Africa.

Lifetime Exposure to Cigarette Smoke, B-Cell Tumor Immune Infiltration, and Immunoglobulin Abundance in Ovarian Tumors

BACKGROUND

Cigarette smoke exposure has been linked to systemic immune dysfunction, including for B-cell and immunoglobulin (Ig) production, and poor outcomes in patients with ovarian cancer. No study has evaluated the impact of smoke exposure across the life-course on B-cell infiltration and Ig abundance in ovarian tumors.

METHODS

We measured markers of B and plasma cells and Ig isotypes using multiplex immunofluorescence on 395 ovarian cancer tumors in the Nurses' Health Study (NHS)/NHSII. We conducted beta-binomial analyses evaluating odds ratios (OR) and 95% confidence intervals (CI) for positivity of immune markers by cigarette exposure among cases and Cox proportional hazards models to evaluate hazard ratios (HR) and 95% CI for developing tumors with low (

RESULTS

There were no associations between smoke exposure and B-cell or IgM infiltration in ovarian tumors. Among cases, we observed higher odds of IgA+ among ever smokers (OR, 1.54; 95% CI, 1.14-2.07) and ever smokers with no parental smoke exposure (OR, 2.03; 95% CI, 1.18-3.49) versus never smokers. Women with parental cigarette smoke exposure versus not had higher risk of developing ovarian cancer with low IgG+ (HR, 1.51; 95% CI, 1.10-2.09), whereas ever versus never smokers had a lower risk (HR, 0.74; 95% CI, 0.56-0.99).

CONCLUSIONS

Ever smoking was associated with increased odds of IgA in ovarian tumors.

IMPACT

IgA has been associated with improved ovarian cancer outcomes, suggesting that although smoking is associated with poor outcomes in patients with ovarian cancer, it may lead to improved tumor immunogenicity.

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Key Words

• smoking
• ovarian cancer
• immune
• b cells
• risk

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MESH Headings

• Humans
• Female
• Ovarian Neoplasms/immunology
• Ovarian Neoplasms/pathology
• Ovarian Neoplasms/epidemiology
• Middle Aged
• Adult
• B-Lymphocytes/immunology
• Immunoglobulins/blood
• Lymphocytes, Tumor-Infiltrating/immunology
• Aged
• Cigarette Smoking/adverse effects
• Cigarette Smoking/immunology

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Grants

• P01 CA087969 NCI NIH HHS
• 9JK02 Florida Department of Health (DOH)
• UM1 CA186107 NCI NIH HHS
• P01 CA87969 National Cancer Institute (NCI)
• U01 CA232758 NCI NIH HHS
• U01 CA176726 NCI NIH HHS

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Affiliation(s)

Cassandra A. Hathaway Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, USA
Mary K. Townsend Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, USA
Tianyi Wang Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, USA
Christine Vinci Department of Health Outcomes and Behavior, Moffitt Cancer Center, Tampa, Florida, USA
Danielle E. Jake-Schoffman Department of Health Education and Behavior, University of Florida, Gainesville, Florida, USA
Jonathan L. Hecht Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
Daryoush Saeed-Vafa Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, Florida, USA Advanced Analytical and Digital Laboratory, Moffitt Cancer Center, Tampa, Florida, USA
Carlos Moran Segura Advanced Analytical and Digital Laboratory, Moffitt Cancer Center, Tampa, Florida, USA
Jonathan V. Nguyen Advanced Analytical and Digital Laboratory, Moffitt Cancer Center, Tampa, Florida, USA
Jose R. Conejo-Garcia Department of Immunology, Duke University School of Medicine, Durham, North Carolina, USA
Brooke L. Fridley Department of Biostatistics and Bioinformatics, Moffitt Cancer Center, Tampa, Florida, USA
Shelley S. Tworoger Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, USA Knight Cancer Institute and Division of Oncological Sciences, Oregon Health & Science University, Portland, OR

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Collaborators Collapse

Native N-glycome profiling of single cells and ng-level blood isolates using label-free capillary electrophoresis-mass spectrometry

The development of reliable single-cell dispensers and substantial sensitivity improvement in mass spectrometry made proteomic profiling of individual cells achievable. Yet, there are no established methods for single-cell glycome analysis due to the inability to amplify glycans and sample losses associated with sample processing and glycan labeling. In this work, we present an integrated platform coupling online in-capillary sample processing with high-sensitivity label-free capillary electrophoresis-mass spectrometry for N-glycan profiling of single mammalian cells. Direct and unbiased quantitative characterization of single-cell surface N-glycomes are demonstrated for HeLa and U87 cells, with the detection of up to 100 N-glycans per single cell. Interestingly, N-glycome alterations are unequivocally detected at the single-cell level in HeLa and U87 cells stimulated with lipopolysaccharide. The developed workflow is also applied to the profiling of ng-level amounts (5-500 ng) of blood-derived protein, extracellular vesicle, and total plasma isolates, resulting in over 170, 220, and 370 quantitated N-glycans, respectively.

Effect of in ovo feeding of xylobiose and xylotriose on plasma immunoglobulin, cecal metabolites production, microbial ecology, and metabolic pathways in broiler chickens

BACKGROUND

Dietary supplementation of xylooligosaccharides (XOS) has been found to influence gut health by manipulating cecal microbiota and producing microbe-origin metabolites. But no study investigated and compared the effect of in ovo feeding of xylobiose (XOS2) and xylotriose (XOS3) in chickens. This study investigated the effect of in ovo feeding of these XOS compounds on post-hatch gut health parameters in chickens. A total of 144 fertilized chicken eggs were divided into three groups: a) non-injected control (CON), b) XOS2, and c) XOS3. On the 17th embryonic day, the eggs of the XOS2 and XOS3 groups were injected with 3 mg of XOS2 and XOS3 diluted in 0.5 mL of 0.85% normal saline through the amniotic sac. After hatching, the chicks were raised for 21 d. Blood was collected on d 14 to measure plasma immunoglobulin. Cecal digesta were collected for measuring short-chain fatty acids (SCFA) on d 14 and 21, and for microbial ecology and microbial metabolic pathway analyses on d 7 and 21.

RESULTS

The results were considered significantly different at P < 0.05. ELISA quantified plasma IgA and IgG on d 14 chickens, revealing no differences among the treatments. Gas chromatography results showed no significant differences in the concentrations of cecal SCFAs on d 14 but significant differences on d 21. However, the SCFA concentrations were lower in the XOS3 than in the CON group on d 21. The cecal metagenomics data showed that the abundance of the family Clostridiaceae significantly decreased on d 7, and the abundance of the family Oscillospiraceae increased on d 21 in the XOS2 compared to the CON. There was a reduction in the relative abundance of genus Clostridium sensu stricto 1 in the XOS2 compared to the CON on d 7 and the genus Ruminococcus torques in both XOS2 and XOS3 groups compared to the CON on d 21. The XOS2 and XOS3 groups reduced the genes for chondroitin sulfate degradation I and L-histidine degradation I pathways, which contribute to improved gut health, respectively, in the microbiome on d 7. In contrast, on d 21, the XOS2 and XOS3 groups enriched the thiamin salvage II, L-isoleucine biosynthesis IV, and O-antigen building blocks biosynthesis (E. coli) pathways, which are indicative of improved gut health. Unlike the XOS3 and CON, the microbiome enriched the pathways associated with energy enhancement, including flavin biosynthesis I, sucrose degradation III, and Calvin-Benson-Bassham cycle pathways, in the XOS2 group on d 21.

CONCLUSION

In ovo XOS2 and XOS3 feeding promoted beneficial bacterial growth and reduced harmful bacteria at the family and genus levels. The metagenomic-based microbial metabolic pathway profiling predicted a favorable change in the availability of cecal metabolites in the XOS2 and XOS3 groups. The modulation of microbiota and metabolic pathways suggests that in ovo XOS2 and XOS3 feeding improved gut health during the post-hatch period of broilers.

A portable surface plasmon resonance (SPR) sensor for the detection of immunoglobulin A in plasma

BACKGROUND

A life-threatening anaphylactic shock can occur if a patient with undiagnosed immunoglobulin A (IgA) deficiency (i.e., IgA levels <500 ng/mL) receives IgA-containing blood, hence the need for a rapid, point-of-care (POC) method for IgA deficiency screening. Enzyme-linked immunosorbent assay (ELISA) is routinely used to detect IgA, but this method requires trained specialists and ≥24 h to obtain a result. We developed a surface plasmon resonance (SPR)-based protocol to identify IgA-deficient patients or donors within 1 h.

MATERIALS AND METHODS

The SPR sensor relies on the detection of IgAs captured by primary antibodies adsorbed on the SPR chip and quantified with secondary antibodies. The sensor was calibrated from 0 to 2000 ng/mL in buffer, IgA-depleted human serum, and plasma samples from IgA-deficient individuals. A critical concentration of 500 ng/mL was set for IgA deficiency. The optimized sensor was then tested on eight plasma samples with known IgA status (determined by ELISA), including five with IgA deficiency and three with normal IgA levels.

RESULTS

The limit of detection was estimated at 30 ng/mL in buffer and 400 ng/mL in diluted plasma. The results obtained fully agreed with ELISA among the eight plasma samples tested. The protocol distinguished IgA-deficient from normal samples, even for samples with an IgA concentration closer to critical concentration.

DISCUSSION

In conclusion, we developed a reliable POC assay for the quantification of IgA in plasma. This test may permit POC testing at blood drives and centralized centers to maintain reserves of IgA-deficient blood and in-hospital testing of blood recipients.

Intravenous immunoglobulins for the treatment of prolonged COVID-19 in immunocompromised patients: a brief report

Primary humoral deficiency and secondary B-cell depletion may lead to prolonged Sars-Cov-2 infection due to a decreased viral clearance. Prolonged infection is mainly driven by the lack of anti-Sars-Cov-2 immunoglobulin (IVIg) especially in patients with no vaccine response. Anti-spike immunoglobulin can be provided by infusion of convalescent patients' plasma: recent studies highlighted that commercial immunoglobulin show high titers of neutralizing IgG. We conducted a single center retrospective cohort. We included 9 patients (6 males, median age 74 years old): one patient with X-linked agammaglobulinemia and 8 patients treated with rituximab (2 granulomatosis with polyangiitis, 1 neuromyelitis optica, 4 low grade B-cell lymphoma and 1 EBV post-transplant lymphoproliferative disorder). Mean serum globulin was 4 ± 1.6 g/L. 7/8 had received at least 3 doses of mRNA anti-Sars-Cov-2 vaccine (median 4) with no response (anti-Spike IgG 0 for 6 patients). In this specific population requiring oxygen therapy but no intensive care support, the administration of IVIg was well tolerated and provided a swift improvement of clinical status, a significant decrease of inflammation associated to the an improvement of radiological patterns. Our results suggest that immunoglobulin could be used as a salvage therapy as an alternative to convalescent plasma but highly stringent patient selection is required due to the worldwide shortage of IVIg.

Fluorine-modified polymers reduce the adsorption of immune-reactive proteins to PEGylated gold nanoparticles

Aim: To investigate the influence of fluorine in reducing the adsorption of immune-reactive proteins onto PEGylated gold nanoparticles. Methods: Reversible addition fragmentation chain transfer polymerization, the Turkevich method and ligand exchange were used to prepare polymer-coated gold nanoparticles. Subsequent in vitro physicochemical and biological characterizations and proteomic analysis were performed. Results: Fluorine-modified polymers reduced the adsorption of complement and other immune-reactive proteins while potentially improving circulatory times and modulating liver toxicity by reducing apolipoprotein E adsorption. Fluorine actively discouraged phagocytosis while encouraging the adsorption of therapeutic targets, CD209 and signaling molecule calreticulin. Conclusion: This study suggests that the addition of fluorine in the surface coating of nanoparticles could lead to improved performance in nanomedicine designed for the intravenous delivery of cargos.

Lupus IgA1 autoantibodies synergize with IgG to enhance pDC responses to RNA-containing immune complexes

Autoantibodies to nuclear antigens are hallmarks of the autoimmune disease systemic lupus erythematosus (SLE) where they contribute to pathogenesis. However, there remains a gap in our knowledge regarding how different isotypes of autoantibodies contribute to disease, including the production of the critical type I interferon (IFN) cytokines by plasmacytoid dendritic cells (pDCs) in response to immune complexes (ICs). We focused on IgA, which is the second most prevalent isotype in serum, and along with IgG is deposited in glomeruli in lupus nephritis. Here, we show that individuals with SLE have IgA autoantibodies against most nuclear antigens, correlating with IgG against the same antigen. We investigated whether IgA autoantibodies against a major SLE autoantigen, Smith ribonucleoproteins (Sm/RNPs), play a role in IC activation of pDCs. We found that pDCs express the IgA-specific Fc receptor, FcαR, and there was a striking ability of IgA1 autoantibodies to synergize with IgG in RNA-containing ICs to generate robust pDC IFNα responses. pDC responses to these ICs required both FcαR and FcγRIIa, showing a potent synergy between these Fc receptors. Sm/RNP IC binding to and internalization by pDCs were greater when ICs contained both IgA1 and IgG. pDCs from individuals with SLE had higher binding of IgA1-containing ICs and higher expression of FcαR than pDCs from healthy control individuals. Whereas pDC FcαR expression correlated with blood ISG signature in SLE, TLR7 agonists, but not IFNα, upregulated pDC FcαR expression in vitro. Together, we show a new mechanism by which IgA1 autoantibodies contribute to SLE pathogenesis.

B cell development and antibody responses in human immune system mice: current status and future perspective

Humanized immune system (HIS) mice have been developed and used as a small surrogate model to study human immune function under normal or disease conditions. Although variations are found between models, most HIS mice show robust human T cell responses. However, there has been unsuccessful in constructing HIS mice that produce high-affinity human antibodies, primarily due to defects in terminal B cell differentiation, antibody affinity maturation, and development of primary follicles and germinal centers. In this review, we elaborate on the current knowledge about and previous attempts to improve human B cell development in HIS mice, and propose a potential strategy for constructing HIS mice with improved humoral immunity by transplantation of human follicular dendritic cells (FDCs) to facilitate the development of secondary follicles.

Immunological Signatures in Blood and Urine in 80 Individuals Hospitalized during the Initial Phase of COVID-19 Pandemic with Quantified Nicotine Exposure

This research analyzes immunological response patterns to SARS-CoV-2 infection in blood and urine in individuals with serum cotinine-confirmed exposure to nicotine. Samples of blood and urine were obtained from a total of 80 patients admitted to hospital within 24 h of admission (tadm), 48 h later (t48h), and 7 days later (t7d) if patients remained hospitalized or at discharge. Serum cotinine above 3.75 ng/mL was deemed as biologically significant exposure to nicotine. Viral load was measured with serum SARS-CoV-2 S-spike protein. Titer of IgG, IgA, and IgM against S- and N-protein assessed specific antiviral responses. Cellular destruction was measured by high mobility group box protein-1 (HMGB-1) serum levels and heat shock protein 60 (Hsp-60). Serum interleukin 6 (IL-6), and ferritin gauged non-specific inflammation. The immunological profile was assessed with O-link. Serum titers of IgA were lower at tadm in smokers vs. nonsmokers (p = 0.0397). IgM at t48h was lower in cotinine-positive individuals (p = 0.0188). IgG did not differ between cotinine-positive and negative individuals. HMGB-1 at admission was elevated in cotinine positive individuals. Patients with positive cotinine did not exhibit increased markers of non-specific inflammation and tissue destruction. The blood immunological profile had distinctive differences at admission (MIC A/B↓), 48 h (CCL19↓, MCP-3↓, CD28↑, CD8↓, IFNγ↓, IL-12↓, GZNB↓, MIC A/B↓) or 7 days (CD28↓) in the cotinine-positive group. The urine immunological profile showed a profile with minimal overlap with blood as the following markers being affected at tadm (CCL20↑, CXCL5↑, CD8↑, IL-12↑, MIC A/B↑, GZNH↑, TNFRS14↑), t48h (CCL20↓, TRAIL↓) and t7d (EGF↑, ADA↑) in patients with a cotinine-positive test. Here, we showed a distinctive immunological profile in hospitalized COVID-19 patients with confirmed exposure to nicotine.

Essential role of local antibody distribution in mediating bone-resorbing effects

The link between antibodies and bone mass is debated. Activated IgG, which interacts directly with Fc gamma receptors, stimulates osteoclastogenesis in vitro, and local injection in immune-activated mice leads to bone loss. Multiple myeloma patients with high serum IgG levels have induced osteoclast activation and display bone loss. In addition, bone loss has been linked to serum autoantibodies in autoimmune diseases, including anti-citrullinated protein antibodies (ACPA) in individuals with rheumatoid arthritis (RA). Whether serum IgG or autoantibodies regulate bone mass under healthy conditions is poorly studied. In elderly men, neither serum levels of polyclonal IgG nor autoantibody were associated with areal bone mineral density in the MrOS Sweden study. Repetitive systemic injections of high-dose polyclonal IgG complexes in mice did not exert any discernible impact on bone mineral density. However, repetitive local intra-articular injection of the same IgG complexes led to a localized reduction of trabecular bone density. These results indicate antibodies may only impact bone density when close to the bone, such as within the synovial joint.

Enhancing affinity purification of monoclonal antibodies from human serum for subsequent CZE-MS analysis

Due to the separation technique employed, capillary electrophoresis coupled to mass spectrometry (CE-MS) analysis performances are significantly influenced by the chemical composition and the complexity of the sample. In various applications, that impact has prevented the use of CE-MS for the characterization and quantification of proteins in biological samples. Here we present the development and evaluation and a sample preparation procedure, based on affinity purification, for the specific extraction of the monoclonal antibody (mAbs) infliximab from human serum in order to perform subsequent proteolytic digestion and CE-MS/MS analysis. Three distinctive sample preparation strategies were envisaged. In each case, the different steps composing the protocol were thoroughly optimized and evaluated in order to provide a sample preparation addressing the important complexity of serums samples while providing an optimal compatibility with CE-MS/MS analysis. The different sample preparation strategies were assessed concerning the possibility to achieve an appropriate absolute quantification of the mAbs using CE-MS/MS for samples mimicking patient serum samples. Also, the possibility to perform the characterization of several types of post-translational modifications (PTMs) was evaluated. The sample preparation protocols allowed the quantification of the mAbs in serums samples for concentration as low as 0.2 µg·mL-1 (2.03 nM) using CE-MS/MS analysis, also the possibility to characterize and estimate the modification level of PTMs hotspots in a consistent manner. Results allowed to attribute the effect on the electrophoretic separation of the different steps composing sample preparation. Finally, they demonstrated that sample preparation for CE-MS/MS analysis could benefit greatly for the extended applicability of this type of analysis for complex biological matrices.

Development of an impedance-based biosensor for determination of IgG galactosylation levels

The glycan profile of immunoglobulin G (IgG) molecule and its changes are associated with a number of different diseases. Galactosylation of IgG was recently suggested as a potential biomarker for rheumatoid arthritis, inflammatory bowel disease and many cancers. In this paper, we propose a portable impedance-based biosensor that utilizes lectin array technology to detect glycans in IgG. Biotinylated Griffonia simplicifolia (GSL II) and Ricinus communis agglutinin I (RCA I) lectins were used in our biosensor design for determination of the ratio of N-acetyl glucosamine (GlcNAc) to galactose (Gal) respectively, which is termed agalactosylation factor (AF). Streptavidin gold nanoparticles (GNP) were conjugated to biotinylated lectin bonded to the carbohydrate in the glycoprotein to magnify the change in impedance signal and enhance detection sensitivity. The method was successfully applied to differentiation of the galactosylation levels in human and rat IgG. In addition, we present proof of concept use of our biosensor for differentiation of COVID-19 positive patient samples from negative patients. Consequently, the sensor can be useful in future applications to distinguish between glycan profiles of IgG from healthy and patient samples in disease studies. Our biosensor permits analysis of human serum without conventional time-consuming IgG purification steps or pretreatment using enzyme digestion to cut the sugars from the glycoprotein molecule. The results suggest that the proposed point of care (POC) biosensor can be used for evaluating disease progression and treatment efficacy via monitoring changes in the galactosylation profiles of IgG in patients.

Multiplexed Antibody Glycosylation Profiling Using Dual Enzyme Digestion and Liquid Chromatography-Triple Quadrupole Mass Spectrometry Method

Antibody glycosylation plays a crucial role in the humoral immune response by regulating effector functions and influencing the binding affinity to immune cell receptors. Previous studies have focused mainly on the immunoglobulin G (IgG) isotype owing to the analytical challenges associated with other isotypes. Thus, the development of a sensitive and accurate analytical platform is necessary to characterize antibody glycosylation across multiple isotypes. In this study, we have developed an analytical workflow using antibody-light-chain affinity beads to purify IgG, IgA, and IgM from 16 μL of human plasma. Dual enzymes, trypsin and Glu-C, were used during on-bead digestion to obtain enzymatic glycopeptides and protein-specific surrogate peptides. Ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry was used in order to determine the sensitivity and specificity. Our platform targets 95 glycopeptides across the IgG, IgA, and IgM isotypes, as well as eight surrogate peptides representing total IgG, four IgG classes, two IgA classes, and IgM. Four stable isotope-labeled internal standards were added after antibody purification to calibrate the preparation and instrumental bias during analysis. Calibration curves constructed using serially diluted plasma samples showed good curve fitting (R2 > 0.959). The intrabatch and interbatch precision for all the targets had relative standard deviation of less than 29.6%. This method was applied to 19 human plasma samples, and the glycosylation percentages were calculated, which were comparable to those reported in the literature. The developed method is sensitive and accurate for Ig glycosylation profiling. It can be used in clinical investigations, particularly for detailed humoral immune profiling.