N-Glycosylation Profiles of Immunoglobulin G and Future Cardiovascular Events.

BACKGROUND: Posttranslational glycosylation of IgG can modulate its inflammatory capacity through structural variations. We examined the association of baseline IgG N-glycans and an IgG glycan score with incident cardiovascular disease (CVD). METHODS: IgG N-glycans were measured in 2 nested CVD case-control studies: JUPITER (Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin; NCT00239681; primary prevention; discovery; Npairs=162); and TNT trial (Treating to New Targets; NCT00327691; secondary prevention; validation; Npairs=397). Using conditional logistic regression, we investigated the association of future CVD with baseline IgG N-glycans and a glycan score adjusting for clinical risk factors (statin treatment, age, sex, race, lipids, hypertension, and smoking) in JUPITER. Significant associations were validated in TNT, using a similar model further adjusted for diabetes. Using least absolute shrinkage and selection operator regression, an IgG glycan score was derived in JUPITER as a linear combination of selected IgG N-glycans. RESULTS: Six IgG N-glycans were associated with CVD in both studies: an agalactosylated glycan (IgG-GP4) was positively associated, while 3 digalactosylated glycans (IgG glycan peaks 12, 13, 14) and 2 monosialylated glycans (IgG glycan peaks 18, 20) were negatively associated with CVD after multiple testing correction (overall false discovery rate <0.05). Four selected IgG N-glycans comprised the IgG glycan score, which was associated with CVD in JUPITER (adjusted hazard ratio per glycan score SD, 2.08 [95% CI, 1.52-2.84]) and validated in TNT (adjusted hazard ratio per SD, 1.20 [95% CI, 1.03-1.39]). The area under the curve changed from 0.693 for the model without the score to 0.728 with the score in JUPITER (PLRT=1.1×10-6) and from 0.635 to 0.637 in TNT (PLRT=0.017). CONCLUSIONS: An IgG N-glycan profile was associated with incident CVD in 2 populations (primary and secondary prevention), involving an agalactosylated glycan associated with increased risk of CVD, while several digalactosylated and sialylated IgG glycans associated with decreased risk. An IgG glycan score was positively associated with future CVD.

The IgG-specific endoglycosidases EndoS and EndoS2 are distinguished by conformation and antibody recognition.

The IgG-specific endoglycosidases EndoS and EndoS2 from Streptococcus pyogenes can remove conserved N-linked glycans present on the Fc region of host antibodies to inhibit Fc-mediated effector functions. These enzymes are therefore being investigated as therapeutics for suppressing unwanted immune activation, and have additional application as tools for antibody glycan remodeling. EndoS and EndoS2 differ in Fc glycan substrate specificity due to structural differences within their catalytic glycosyl hydrolase domains. However, a chimeric EndoS enzyme with a substituted glycosyl hydrolase from EndoS2 loses catalytic activity, despite high structural homology between the two enzymes, indicating either mechanistic divergence of EndoS and EndoS2, or improperly-formed domain interfaces in the chimeric enzyme. Here, we present the crystal structure of the EndoS2-IgG1 Fc complex determined to 3.0 Å resolution. Comparison of complexed and unliganded EndoS2 reveals relative reorientation of the glycosyl hydrolase, leucine-rich repeat and hybrid immunoglobulin domains. The conformation of the complexed EndoS2 enzyme is also different when compared to the earlier EndoS-IgG1 Fc complex, and results in distinct contact surfaces between the two enzymes and their Fc substrate. These findings indicate mechanistic divergence of EndoS2 and EndoS. It will be important to consider these differences in the design of IgG-specific enzymes, developed to enable customizable antibody glycosylation.

Molecular characterization of the interaction between human IgG and the M-related proteins from Streptococcus pyogenes.

Group A Streptococcal M-related proteins (Mrps) are dimeric α-helical-coiled-coil cell membrane-bound surface proteins. During infection, Mrp recruit the fragment crystallizable region of human immunoglobulin G via their A-repeat regions to the bacterial surface, conferring upon the bacteria enhanced phagocytosis resistance and augmented growth in human blood. However, Mrps show a high degree of sequence diversity, and it is currently not known whether this diversity affects the Mrp-IgG interaction. Herein, we report that diverse Mrps all bind human IgG subclasses with nanomolar affinity, with differences in affinity which ranged from 3.7 to 11.1 nM for mixed IgG. Using surface plasmon resonance, we confirmed Mrps display preferential IgG-subclass binding. All Mrps were found to have a significantly weaker affinity for IgG3 (p < 0.05) compared to all other IgG subclasses. Furthermore, plasma pulldown assays analyzed via Western blotting revealed that all Mrp were able to bind IgG in the presence of other serum proteins at both 25 °C and 37 °C. Finally, we report that dimeric Mrps bind to IgG with a 1:1 stoichiometry, enhancing our understanding of this important host-pathogen interaction.

Identification of potential C1-binding sites in the immunoglobulin CL domains.

Immunoglobulin G (IgG) molecules that bind antigens on the membrane of target cells spontaneously form hexameric rings, thus recruiting C1 to initiate the complement pathway. However, our previous report indicated that a mouse IgG mutant lacking the Cγ1 domain activates the pathway independently of antigen presence through its monomeric interaction with C1q via the CL domain, as well as Fc. In this study, we investigated the potential interaction between C1q and human CL isoforms. Quantitative single-molecule observations using high-speed atomic force microscopy revealed that human Cκ exhibited comparable C1q binding capabilities with its mouse counterpart, surpassing the Cλ types, which have a higher isoelectric point than the Cκ domains. Nuclear magnetic resonance and mutation experiments indicated that the human and mouse Cκ domains share a common primary binding site for C1q, centred on Glu194, a residue conserved in the Cκ domains but absent in the Cλ domains. Additionally, the Cγ1 domain, with its high isoelectric point, can cause electrostatic repulsion to the C1q head and impede the C1q-interaction adjustability of the Cκ domain in Fab. The removal of the Cγ1 domain is considered to eliminate these factors and thus promote Cκ interaction with C1q with the potential risk of uncontrolled activation of the complement pathway in vivo in the absence of antigen. However, this research underscores the presence of potential subsites in Fab for C1q binding, offering promising targets for antibody engineering to refine therapeutic antibody design.

Comparative Analysis of Laboratory-Scale Immunoglobulin G Purification Methods from Human Serum.

Immunoglobulin G (IgG) purification is a critical process for evaluating its role in autoimmune diseases, which are defined by the occurrence of autoantibodies. Affinity chromatography with protein G is widely considered to be the optimal technique for laboratory-scale purification. However, this technique has some limitations, including the exposure of IgG to low pH, which can compromise the quality of the purified IgG. Here, we show that alternative methods for IgG purification are possible while maintaining the quality of IgG. Different techniques for IgG purification from serum were evaluated and compared with protein G-based approaches: Melon Gel, caprylic acid-ammonium sulfate (CAAS) precipitation, anion-exchange chromatography with diethylamino ethyl (DEAE) following ammonium sulfate (AS) precipitation, and AS precipitation alone. The results demonstrated that the purification yield of these techniques surpassed that of protein G. However, differences in the purity of IgG were observed using GeLC-MS/MS. The avidity of purified IgG against selected targets (SARS-CoV-2 and topoisomerase-I) was similar between purified IgG obtained using all techniques and unpurified sera. Our work provides valuable insights for future studies of IgG function by recommending alternative purification methods that offer advantages in terms of yield, time efficiency, cost-effectiveness, and milder pH conditions than protein G.

A highly specific antibody against the core fucose of the N-glycan in IgG identifies the pulmonary diseases and its regulation by CCL2.

Glycan structure is often modulated in disease or predisease states, suggesting that such changes might serve as biomarkers. Here, we generated a monoclonal antibody (mAb) against the core fucose of the N-glycan in human IgG. Notably, this mAb can be used in Western blotting and ELISA. ELISA using this mAb revealed a low level of the core fucose of the N-glycan in IgG, suggesting that the level of acore fucosylated (noncore fucosylated) IgG was increased in the sera of the patients with lung cancer, chronic obstructive pulmonary disease, and interstitial pneumonia compared to healthy subjects. In a coculture analysis using human lung adenocarcinoma A549 cells and antibody-secreting B cells, the downregulation of the FUT8 (α1,6 fucosyltransferase) gene and a low level of core fucose of the N-glycan in IgG in antibody-secreting B cells were observed after coculture. A dramatic alteration in gene expression profiles for cytokines, chemokines, and their receptors were also observed after coculturing, and we found that the identified C-C motif chemokine 2 was partially involved in the downregulation of the FUT8 gene and the low level of core fucose of the N-glycan in IgG in antibody-secreting B cells. We also developed a latex turbidimetric immunoassay using this mAb. These results suggest that communication with C-C motif chemokine 2 between lung cells and antibody-secreting B cells downregulate the level of core fucose of the N-glycan in IgG, i.e., the increased level of acore fucosylated (noncore fucosylated) IgG, which would be a novel biomarker for the diagnosis of patients with pulmonary diseases.

Antibody-guided proteases enable selective and catalytic degradation of challenging therapeutic targets.

The exquisite specificity, natural biological functions, and favorable development properties of antibodies make them highly effective agents as drugs. Monoclonal antibodies are particularly strong as inhibitors of systemically accessible targets where trough-level concentrations can sustain full target occupancy. Yet beyond this pharmacologic wheelhouse, antibodies perform suboptimally for targets of high abundance and those not easily accessible from circulation. Fundamentally, this restraint on broader application is due largely to the stoichiometric nature of their activity-one drug molecule is generally able to inhibit a maximum of two target molecules at a time. Enzymes in contrast are able to catalytically turnover multiple substrates, making them a natural sub-stoichiometric solution for targets of high abundance or in poorly accessible sites of action. However, enzymes have their own limitations as drugs, including, in particular, the polypharmacology and broad specificity often seen with native enzymes. In this study, we introduce antibody-guided proteolytic enzymes to enable selective sub-stoichiometric turnover of therapeutic targets. We demonstrate that antibody-mediated substrate targeting can enhance enzyme activity and specificity, with proof of concept for two challenging target proteins, amyloid-ß and immunoglobulin G. This work advances a new biotherapeutic platform that combines the favorable properties of antibodies and proteolytic enzymes to more effectively suppress high-bar therapeutic targets.

Exploiting the neonatal crystallizable fragment receptor to treat kidney disease.

The neonatal Fc receptor (FcRn) was initially discovered as the receptor that allowed passive immunity in newborns by transporting maternal IgG through the placenta and enterocytes. Since its initial discovery, FcRn has been found to exist throughout all stages of life and in many different cell types. Beyond passive immunity, FcRn is necessary for intrinsic albumin and IgG recycling and is important for antigen processing and presentation. Given its multiple important roles, FcRn has been utilized in many disease treatments including a new class of agents that were developed to inhibit FcRn for treatment of a variety of autoimmune diseases. Certain cell populations within the kidney also express high levels of this receptor. Specifically, podocytes, proximal tubule epithelial cells, and vascular endothelial cells have been found to utilize FcRn. In this review, we summarize what is known about FcRn and its function within the kidney. We also discuss how FcRn has been used for therapeutic benefit, including how newer FcRn inhibiting agents are being used to treat autoimmune diseases. Lastly, we will discuss what renal diseases may respond to FcRn inhibitors and how further work studying FcRn within the kidney may lead to therapies for kidney diseases.

Immune responses to P falciparum antibodies in symptomatic malaria patients with variant hemoglobin genotypes in Ghana.

BACKGROUND: Haemoglobin (Hb) variants such as sickle cell trait (SCT/HbAS) play a role in protecting against clinical malaria, but little is known about the development of immune responses against malaria parasite (Plasmodium falciparum surface protein 230 (Pfs230) and Plasmodium falciparum erythrocyte binding antigen 175 region-3 (PfEBA175-3R)) and vector (on the An. gambiae Salivary Gland Protein-6 peptide 1 (gSG6-P1)) antigens in individuals with variants Hb genotypes. This study assessed antibody (IgG) responses against malaria parasite, Pfs230 and PfEBA175-3R and vector, gSG6-P1 in febrile individuals with variant Hb genotypes. METHODS: The study was conducted on symptomatic malaria patients attending various healthcare facilities throughout Ghana. Microscopy and ELISA were used to determine the natural IgG antibody levels of gSG6-P1, PfEBA175-3R & Pfs230, and Capillarys 2 Flex Piercing was used for Hb variants determination. RESULTS: Of the 600 symptomatic malaria patients, 50.0% of the participants had malaria parasites by microscopy. The majority 79.0% (398/504) of the participants had Hb AA, followed by HbAS variant at 11.3% (57/504) and HbAC 6.7% (34/504). There were significantly (p < 0.0001) reduced levels of gSG6-P1 IgG in individuals with both HbAC and HbAS genotypes compared to the HbAA genotype. The levels of gSG6-P1 IgG were significantly (p < 0.0001) higher in HbAS compared to HbAC. Similarly, Pfs230 IgG and PfEBA-175-3R IgG distributions observed across the haemoglobin variants were significantly higher in HbAC relative to HbAS. CONCLUSION: The study has shown that haemoglobin variants significantly influence the pattern of anti-gSG6-P1, Pfs230, and PfEBA-175 IgG levels in malaria-endemic population. The HbAS genotype is suggested to confer protection against malaria infection. Reduced exposure to infection ultimately reduces the induction of antibodies targeted against P. falciparum antigens.

Animal models of studying the pathogenesis of multi-organ tissue damage in lupus.

Moderate-to-severe systemic lupus erythematosus (SLE) is characterized by extensive autoantibody deposition and persistent autoinflammation. As the existing animal models are limited in accurately reproducing the pathological characteristics of human SLE, we introduced a novel animal model simulating multi-organ autoinflammation through intra-organ injections. The model closely mimicked key features of SLE, including IgG deposition, inflammation, and tissue damage. The model could be used to assess the roles of IgG, immune cells, cytokines, and Fc gamma receptor (FcγR) in the pathogenesis of autoinflammation. The results obtained from this model could be confirmed by lupus MRL/lpr mice. The review suggested that the diagnostic criteria should be reconsidered to incorporate IgG deposition in tissues and highlighted the limitations of current T-cell and B-cell-focused treatments. To summarize, the IgG deposition model can be used to investigate the pathogenesis and treatment of multi-organ tissue damage associated with SLE.

A phase 1 study in healthy volunteers to investigate the safety, tolerability, and pharmacokinetics of VIR-2482: a monoclonal antibody for the prevention of severe influenza A illness.

The objective of this study was to evaluate the safety, tolerability, pharmacokinetics (PK), and immunogenicity of VIR-2482 in healthy adult subjects. A phase 1, first-in-human, randomized, double-blind, placebo-controlled dose-escalation study was conducted. One hundred participants were allocated to four cohorts (60 mg, 300 mg, 1,200 mg, and 1,800 mg). In each cohort, participants were randomized in a 4:1 ratio (active:placebo) to receive either VIR-2482 or volume-matched placebo by gluteal intramuscular injection. Participants remained at the investigative site under observation for 48 h, and adverse events (AEs) were collected for 56 days. PK and immunogenicity were measured up to 52 weeks post-dose. VIR-2482 was well tolerated at all doses studied. The overall incidence of AEs was comparable between VIR-2482 (68.8%) and placebo (85.0%). Nineteen VIR-2482 (23.8%) and six placebo (30.0%) recipients had Grade 1 or 2 AEs that were considered to be related to the study intervention. There were no treatment-related serious AEs. Injection-site reactions (ISRs) were reported in six (7.5%) VIR-2482 recipients, while no such reactions were reported among the placebo recipients. All ISRs were Grade 1, and there was no relationship with the dose. Median VIR-2482 serum elimination half-life ranged from 56.7 to 70.6 days across cohorts. The serum area under the curve and Cmax were dose-proportional. Nasopharyngeal VIR-2482 concentrations were approximately 2%-5% of serum levels and were less than dose-proportional. The incidence of immunogenicity across all cohorts was 1.3%. Overall, the safety, tolerability, and pharmacokinetic profile of VIR-2482 at doses up to 1,800 mg supported its further investigation as a long-acting antibody for the prevention of influenza A illness. This study has been registered at ClinicalTrials.gov under identifier NCT04033406.

Clinical Perspectives on IgG4-Related Disease and Its Classification.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease. Since its discovery nearly two decades ago, our understanding of its pathophysiology and clinical manifestations has grown substantially. Early diagnosis and treatment of this elusive disease can prevent substantial organ damage from end-stage fibrosis, emphasizing the need for prompt recognition and accurate characterization of IgG4-RD. The classification criteria endorsed by the American College of Rheumatology and the European Alliance of Associations for Rheumatology in 2019 provide a framework for establishing the diagnosis in the clinical setting. This process involves recognizing the typical manifestations of the disease and incorporating clinical, radiological, serological, and histopathological information as well as excluding disease mimickers. Glucocorticoids and rituximab are effective at inducing remission in IgG4-RD in most patients, but the optimal approach to long-term management of IgG4-RD remains an area of active clinical research.

Maternal immunoglobulin G affects brain development of mouse offspring.

Maternal immunoglobulin (Ig)G is present in breast milk and has been shown to contribute to the development of the immune system in infants. In contrast, maternal IgG has no known effect on early childhood brain development. We found maternal IgG immunoreactivity in microglia, which are resident macrophages of the central nervous system of the pup brain, peaking at postnatal one week. Strong IgG immunoreactivity was observed in microglia in the corpus callosum and cerebellar white matter. IgG stimulation of primary cultured microglia activated the type I interferon feedback loop by Syk. Analysis of neonatal Fc receptor knockout (FcRn KO) mice that could not take up IgG from their mothers revealed abnormalities in the proliferation and/or survival of microglia, oligodendrocytes, and some types of interneurons. Moreover, FcRn KO mice also exhibited abnormalities in social behavior and lower locomotor activity in their home cages. Thus, changes in the mother-derived IgG levels affect brain development in offsprings.

Elevated cerebrospinal fluid IgG index in herpes simplex encephalitis post-HSV-1 clearance: A preliminary study.

Herpes simplex encephalitis (HSE) is an acute form of encephalitis that can lead to poor neurological outcomes. Although the exact pathogenesis of HSE remains elusive, recent reports suggest a significant role for postinfectious immune-inflammatory processes in the central nervous system (CNS). This study aimed to clarify the association between CNS autoimmune responses and clinical presentation in patients with HSE, focusing on cerebrospinal fluid (CSF) characteristics, particularly the IgG index. We retrospectively analyzed 176 consecutive patients suspected of having aseptic meningitis /encephalitis for chronological changes in CSF findings and clinical presentations. These patients underwent PCR screening for herpesviruses (HV) in their CSF. We identified seven patients positive for herpes simplex virus type 1 (HSV-1), 20 patients positive for varicella-zoster virus, and 17 patients who met the criteria for aseptic meningitis but were PCR-negative for HV. Patients in the HSV-1-positive group exhibited a significant increase in the IgG index at the time of PCR-negative conversion compared with on admission (p = 0.0156), while such a change was not observed in the other two groups. Additionally, all patients in the HSV-1-positive group tested negative for anti-neural autoantibodies in CSF and serum samples collected approximately 3 weeks after onset. This study, therefore, highlights that CSF IgG index elevation occurs even after PCR-confirmed HSV-1 clearance, which might indicate immunopathogenesis that is independent of antibody-mediated mechanisms.

Evaluation of the effects of the Zika Virus-Immunoglobulin G+ complex on murine microglial cells.

After the Zika virus (ZIKV) epidemic in Brazil, ZIKV infections were linked to damage to the central nervous system (CNS) and congenital anomalies. Due to the virus's ability to cross the placenta and reach brain tissue, its effects become severe, leading to Congenital Zika Syndrome (CZS) and resulting in neuroinflammation, microglial activation, and secretion of neurotoxic factors. The presence of ZIKV triggers an inadequate fetal immune response, as the fetus only has the protection of maternal antibodies of the Immunoglobulin G (IgG) class, which are the only antibodies capable of crossing the placenta. Because of limited understanding regarding the long term consequences of ZIKV infection and the involvement of maternal antibodies, this study sought to assess the impact of the ZIKV + IgG⁺complex on murine microglial cells. The cells were exposed to ZIKV, IgG antibodies, and the ZIKV + IgG⁺complex for 24 and 72 h. Treatment-induced cytotoxic effects were evaluated using the cell viability assay, oxidative stress, and mitochondrial membrane potential. The findings indicated that IgG antibodies exhibit cytotoxic effects on microglia, whether alone or in the presence of ZIKV, leading to compromised cell viability, disrupted mitochondrial membrane potential, and heightened oxidative damage. Our conclusion is that IgG antibodies exert detrimental effects on microglia, triggering their activation and potentially disrupting the creation of a neurotoxic environment. Moreover, the presence of antibodies may correlate with an elevated risk of ZIKV-induced neuroinflammation, contributing to long-term CNS damage.

Changes in serum immunoglobulin G glycosylation patterns for antiphospholipid syndrome patients with lectin microarray.

Antiphospholipid syndrome is a rare autoimmune disease characterized by persistent antiphospholipid antibodies. Immunoglobulin G plays a vital role in disease progression, with its structure and function affected by glycosylation. We aimed to investigate the changes in the serum immunoglobulin G glycosylation pattern in antiphospholipid syndrome patients. We applied lectin microarray on samples from 178 antiphospholipid syndrome patients, 135 disease controls (including Takayasu arteritis, rheumatoid arthritis and cardiovascular disease) and 100 healthy controls. Lectin blots were performed for validation of significant differences. Here, we show an increased immunoglobulin G-binding level of soybean agglutinin (p = 0.047, preferring N-acetylgalactosamine) in antiphospholipid syndrome patients compared with healthy and disease controls. Additionally, the immunoglobulin G from antiphospholipid syndrome patients diagnosed with pregnancy events had lower levels of fucosylation (p = 0.001, recognized by Lotus tetragonolobus) and sialylation (p = 0.030, recognized by Sambucus nigra I) than those with simple thrombotic events. These results suggest the unique serum immunoglobulin G glycosylation profile of antiphospholipid syndrome patients, which may inform future studies to design biomarkers for more accurate diagnosis of antiphospholipid syndrome and even for the prediction of clinical symptoms in patients.

Dynamics of scFv-targeted VAP2 correlating with IL-16, MIF and IL-1Ra in ANCA-associated vasculitis.

BACKGROUND AND HYPOTHESIS: Using a mouse model of MPA with microvascular lesion with a clone (VasSF) of recombinant single chain fragments of the variable region of human IgG, we previously showed that vasculitis-associated apolipoprotein A2 (VAP2) may be a therapeutic target for vasculitis. The present study estimated the target molecules for VasSF and the association between VAP2 and cytokine levels in patient sera in terms of microvascular lesion severity. METHODS: Sera and clinical information were collected from patients with microscopic polyangiitis and granulomatosis with polyangiitis (MPA/GPA) and infectious disease. Neutrophil counts, levels of C-reactive protein (CRP), creatinine, total cholesterol associated with microvascular lesion, HDL cholesterol, low-density lipoprotein cholesterol, triglycerides, glomerular filtration rate (eGFR), and cytokines were estimated. Serum VAP2 signals were determined with Western blotting. RESULTS: VasSF bound to a 24 kDa molecule in the serum of active MPA/GPA patients. Anti-AP2 antibody also bound with the same 24 kDa molecule, named VAP2, because of size difference from normal APOA2. The VAP2 signal was significantly stronger in the active-disease group but significantly weakened in remission. The signal correlated positively with eGFR but not with the Birmingham Vasculitis Activity Score, CRP, MPO-ANCA, or PR3-ANCA levels. It correlated negatively with MPO activity, IL-16, MIF, and IL-1Ra. Moreover, VasSF bound to a 17 kDa molecule in the remission phase. CONCLUSION: The 24 kDa VAP2 molecule may be associated with neutrophil functions because of its inverse correlation with MPO activity, IL-16, MIF, and IL-1Ra, suggesting that VAP2-APOA1 formation in HDL triggers microvascular injury. VasSF may reverse the injury by removing APOA1-VAP2 heterodimers from peripheral blood vessels.

Inflammation induces α1-adrenoceptor expression in peripheral blood mononuclear cells of patients with complex regional pain syndrome.

Persistent regional and systemic inflammation may promote pain and hyperalgesia in complex regional pain syndrome (CRPS). In this study, we investigated whether stimulation of α1-adrenoceptors (α1-AR) on peripheral blood mononuclear cells (PBMC) might contribute to this inflammatory state. PBMC were isolated from venous blood collected from 21 CRPS patients and 21 sex and age-matched controls. Lipopolysaccharide (LPS), a bacterial toxin, was administered to cultured PBMC for 24 h to trigger inflammation. Exposure to LPS resulted in heightened gene expression of α1-AR subtype B (α1B-AR) in PBMC of CRPS patients relative to controls. Interleukin (IL)-1ß and IL-6 levels did not change when the α1-AR agonist phenylephrine was administered to naïve PBMC. However, α1-AR stimulation following LPS treatment increased IL-6 mRNA and protein levels in PBMC of patients and controls. To investigate the possible consequence of heightened IL-6 levels on immunoglobulin G antibody production, PBMC were stimulated with CD40 ligand and IL-21 to generate plasmablasts (B cells that secrete antibodies). This response was similar in patients and controls. Adding IL-6 to the cell culture medium increased plasmablast differentiation in controls and antibody production both in patients and controls. These findings suggest that the inflammatory cascade associated with elevated levels of IL-6 may generate α1B-AR expression in CRPS PBMC. A reciprocal interaction between heightened α1-AR expression in PBMC and IL-6 secretion may contribute to systemic inflammation and antibody production in CRPS.

Liquid Droplet-Mediated Formulation of Lipid Nanoparticles Encapsulating Immunoglobulin G for Cytosolic Delivery.

Antibodies are promising biopharmaceuticals that offer new therapeutic options for diseases. Since antibodies are membrane impermeable, approaches that allow immunoglobulin Gs (IgGs) to access intracellular therapeutic targets would open new horizons in antibody therapies. Lipid nanoparticles (LNPs) are among the classes of vectors that deliver biopharmaceuticals into cells. Using liquid droplets formed by IgG and polyglutamate, we report here a unique approach to forming LNPs containing IgG via liquid droplets formed in the presence of polyglutamic acid (polyE). The addition of polyE promoted the formation of smaller LNPs with cationic lipids than in its absence, and the formed LNPs were much more efficient in cytosolic IgG delivery and targeting of cellular proteins. This approach also allows for the encapsulation of intact IgG without the need for chemical or sequence modification. The intracellularly delivered IgG retained its target binding ability, as demonstrated by labeling of nuclear pore complex and HRas-GFP and inhibition of antiapoptotic cell death by phosphorylated Akt protein in live cells.

Seroprevalence of Toxoplasma gondii immunoglobulins and its association with systemic lupus erythematosus: A systematic review and meta-analysis.

BACKGROUND: The exact cause of systemic lupus erythematosus (SLE) is still unknown. However, hormonal, genetic, and environmental factors may play significant roles in its development. Infection has been recognized as a crucial trigger for SLE development. Several studies have reported a higher prevalence of Toxoplasma gondii infections in patients with SLE than in healthy individuals. However, these results were inconsistent. Therefore, this study aimed to conduct a systematic review and meta-analysis of published studies to provide a definitive conclusion regarding the relationship between T. gondii infection and SLE. MATERIALS AND METHODS: We conducted a comprehensive search across diverse databases using an array of search tools to uncover pertinent literature. Following the stringent application of the inclusion and exclusion criteria, we carefully selected the appropriate reports for our meta-analysis. Using Comprehensive Meta-Analysis software v4, we analyzed the data and determined the prevalence of antibodies against T. gondii in patients affected with SLE. To investigate the correlation between T. gondii seropositivity and SLE, we computed the risk ratios (RRs) and 95% confidence intervals (CI). RESULTS: Eleven studies were considered eligible for inclusion in the present study. The prevalence of anti-IgG and IgM antibodies against T. gondii was 33.9% and 7.7%, respectively. A significant association between T. gondii IgG seropositivity and SLE was observed when compared to the controls (risk ratio = 2.14, 95% CI = 1.42 to 3.22, p = .000). However, IgM seropositivity against T. gondii was comparable between patients with SLE and healthy controls. CONCLUSIONS: In summary, this study suggests that T. gondii IgG is more prevalent in patients with SLE than in healthy individuals in areas where T. gondii infections are more frequent. However, an exact cause-and-effect relationship still needs to be established. Therefore, additional research is necessary to validate these findings and to investigate the underlying mechanisms.