Plasma IgG Research Articles

Long-term administration of CU06-1004 ameliorates cerebrovascular aging and BBB injury in aging mouse model

BackgroundAge-related changes in the cerebrovasculature, including blood–brain barrier (BBB) disruption and vascular dementia, are emerging as potential risks for many neurodegenerative diseases. Therefore, the endothelial cells that constitute the cerebrovasculature may play key roles in preventing brain injury. Our previous study showed that CU06-1004, an endothelial cell dysfunction blocker, prevented vascular leakage, enhanced vascular integrity in ischemic reperfusion injury, and promoted the normalization of tumor vasculature. Here, we evaluated the effects of CU06-1004 on age-related cerebrovascular functional decline in the aged mouse brain.ResultsIn this study, we investigated the protective effects of CU06-1004 against oxidative stress–induced damage in human brain microvascular endothelial cells (HBMECs). HBMECs were treated with hydrogen peroxide (H2O2) to establish an oxidative stress–induced model of cellular injury. Compared with H2O2 treatment alone, pretreatment of HBMECs with CU06-1004 considerably reduced oxidative stress–induced cytotoxicity, reactive oxygen species generation, senescence-associated β-galactosidase activity, senescence marker expression, and the expression levels of inflammatory proteins. Based on the observed cytoprotective effects of CU06-1004 in HBMECs, we examined whether CU06-1004 displayed protective effects against cerebrovascular aging in mice. Long-term administration of CU06-1004 alleviated age-associated cerebral microvascular rarefaction and cerebrovascular senescence in the aged mouse brain. CU06-1004 supplementation also reduced the extravasation of plasma IgG by improving BBB integrity in the aged mouse brain, associated with reductions in neuronal injury. A series of behavioral tests also revealed improved motor and cognitive functions in aged mice that received long-term CU06-1004 administration.ConclusionsThese findings suggest that CU06-1004 may represent a promising therapeutic approach for delaying age-related cerebrovascular impairment and improving cognitive function in old age.

Further analysis of natural antibodies against ischemic stroke.

Our previous study revealed that circulating levels of IgG natural antibodies (NAbs) for vascular endothelial growth factor receptor 1 (VEGFR1) were significantly decreased in patients with arteriosclerosis compared with control subjects. To enhance the sensitivity of an enzyme-linked immunosorbent assay (ELISA) developed in-house for antibody testing, the present work was designed to investigate additive signals in the in-house ELISA developed with the combination of two or more linear peptide antigens derived from target proteins of interest, including VEGFR1, oxidized low-density lipoprotein receptor 1 (LOX-1), interleukins 6 (IL6) and 8 (IL8). A total of 218 patients with ischemic stroke and 198 healthy controls were enrolled and an in-house ELISA was developed with linear peptides derived from VEGFR1, LOX-1, IL6, and IL8 to detect their IgG levels in plasma. Compared with control subjects, plasma levels of IgG NAbs for the IL6-IL8 combination were significantly lower in female patients (Z = -3.149, P = 0.002), whereas male patients showed significantly lower levels of plasma anti-VEGFR IgG (Z = -3.895, P < 0.001) and anti-LOX1a IgG (Z = -4.329, P < 0.001). Because plasma levels of IgG NAbs for both the IL6-IL8-LOX1a-LOX1b combination and the VEGFR1a-VEGFR1b-LOX1a-LOX1b combination were significantly lower in the patient group than the control group, receiver operating characteristic (ROC) analysis was performed and the results showed that the VEGFR1a-VEGFR1b-LOX1a-LOX1b combination had an area under the ROC curve (AUC) of 0.70 for its IgG assay with a sensitivity of 27.1% against the specificity of 95.5% and that the IL6-IL8-LOX1a-LOX1b combination had an AUC of 0.67 for its IgG assay with a sensitivity of 21.1% against the specificity of 95.5%. Spearman correlation analysis showed that plasma IgG NAbs against the IL6-IL8 combination were positively correlated with carotid plaque size only in male patients (r = 0.270, p = 0.002). Circulating IgG NAbs for the target molecules studied may be potential biomarkers for a subgroup of ischemic stroke and also contribute to the gender differences in clinical presentation of the disease.

Toward systems-informed models for biologics disposition: covariates of the abundance of the neonatal Fc Receptor (FcRn) in human tissues and implications for pharmacokinetic modelling

Biologics are a fast-growing therapeutic class, with intertwined pharmacokinetics and pharmacodynamics, affected by the abundance and function of the FcRn receptor. While many investigators assume adequacy of classical models, such as allometry, for pharmacokinetic characterization of biologics, advocates of physiologically-based pharmacokinetics (PBPK) propose consideration of known systems parameters that affect the fate of biologics to enable a priori predictions, which go beyond allometry. The aim of this study was to deploy a systems-informed modelling approach to predict the disposition of Fc-containing biologics. We used global proteomics to quantify the FcRn receptor [p51 and β2-microglobulin (B2M) subunits] in 167 samples of human tissue (liver, intestine, kidney and skin) and assessed covariates of its expression. FcRn p51 subunit was highest in liver relative to other tissues, and B2M was 1–2 orders of magnitude more abundant than FcRn p51 across all sets. There were no sex-related differences, while higher expression was confirmed in neonate liver compared with adult liver. Trends of expression in liver and kidney indicated a moderate effect of body mass index, which should be confirmed in a larger sample size. Expression of FcRn p51 subunit was approximately 2-fold lower in histologically normal liver tissue adjacent to cancer compared with healthy liver. FcRn mRNA in plasma-derived exosomes correlated moderately with protein abundance in matching liver tissue, opening the possibility of use as a potential clinical tool. Predicted effects of trends in FcRn abundance in healthy and disease (cancer and psoriasis) populations using trastuzumab and efalizumab PBPK models were in line with clinical observations, and global sensitivity analysis revealed endogenous IgG plasma concentration and tissue FcRn abundance as key systems parameters influencing exposure to Fc-conjugated biologics.

The protective effect of butylated hydroxytoluene and 3-hydroxytyrosol on food allergy in mice

Objective To test the effect of two dietary antioxidants: butylated hydroxytoluene (BHT) and 3-hydroxytyrosol (3-HT) in experimental food allergy. Methods BALB/c mice maintained on control diet or diet with BHT or 3-HT were sensitized with ovalbumin (OVA) or saline through transdermal exposure. Plasma OVA-specific IgE (OVA-IgE) and IgG1 (OVA-IgG1) antibody levels were determined using ELISA. Sensitized mice were challenged by oral gavage with OVA. Rectal temperature (RT) was measured before and after challenge. Mast cell degranulation was quantified by measuring the plasma levels of mouse mucosal mast cell protease-1 (mMCP-1). Flow cytometry was carried out to evaluate the percentage Th2 cells from the spleen. Results Mice on either a 3-HT or BHT diet showed a significantly decreased IgE response to OVA sensitization and less severe anaphylaxis, as evidenced by a diminished drop in body temperature, attenuated clinical signs, a more rapid recovery and decreased mast cell degranulation (as determined by lower plasma mMCP-1 levels). Conclusion The present study indicates two dietary antioxidants: BHT and 3-HT may be protective against experimental food allergy. These results suggest 3-HT and BHT could potentially be useful for prevention of food allergy.

SARS-CoV-2-specific nasal IgA wanes 9 months after hospitalisation with COVID-19 and is not induced by subsequent vaccination.

Most studies of immunity to SARS-CoV-2 focus on circulating antibody, giving limited insights into mucosal defences that prevent viral replication and onward transmission. We studied nasal and plasma antibody responses one year after hospitalisation for COVID-19, including a period when SARS-CoV-2 vaccination was introduced. In this follow up study, plasma and nasosorption samples were prospectively collected from 446 adults hospitalised for COVID-19 between February 2020 and March 2021 via the ISARIC4C and PHOSP-COVID consortia. IgA and IgG responses to NP and S of ancestral SARS-CoV-2, Delta and Omicron (BA.1) variants were measured by electrochemiluminescence and compared with plasma neutralisation data. Strong and consistent nasal anti-NP and anti-S IgA responses were demonstrated, which remained elevated for nine months (p<0.0001). Nasal and plasma anti-S IgG remained elevated for at least 12 months (p<0.0001) with plasma neutralising titres that were raised against all variants compared to controls (p<0.0001). Of 323 with complete data, 307 were vaccinated between 6 and 12 months; coinciding with rises in nasal and plasma IgA and IgG anti-S titres for all SARS-CoV-2 variants, although the change in nasal IgA was minimal (1.46-fold change after 10 months, p=0.011) and the median remained below the positive threshold determined by pre-pandemic controls. Samples 12 months after admission showed no association between nasal IgA and plasma IgG anti-S responses (R=0.05, p=0.18), indicating that nasal IgA responses are distinct from those in plasma and minimally boosted by vaccination. The decline in nasal IgA responses 9 months after infection and minimal impact of subsequent vaccination may explain the lack of long-lasting nasal defence against reinfection and the limited effects of vaccination on transmission. These findings highlight the need to develop vaccines that enhance nasal immunity. This study has been supported by ISARIC4C and PHOSP-COVID consortia. ISARIC4C is supported by grants from the National Institute for Health and Care Research and the Medical Research Council. Liverpool Experimental Cancer Medicine Centre provided infrastructure support for this research. The PHOSP-COVD study is jointly funded by UK Research and Innovation and National Institute of Health and Care Research. The funders were not involved in the study design, interpretation of data or the writing of this manuscript.

ПАРАМЕТРИ ЛІПІДНОГО ПРОФІЛЮ У ДОНОРІВ, ЯКІ ПЕРЕХВОРІЛИ НА COVID-19 ТА МАЮТЬ РІЗНІ ТИТРИ АНТИ-SARS-CoV-2 IgG У ПЛАЗМІ КРОВІ

COVID-19, caused by SARS-CoV-2, is a systemic disorder of with possible pathological complications in human organism. One of the critical targets of SARS-CoV-2 is the metabolism of lipids and products, which may influence the changes in patients with illness. Currently, the mechanism of binding between SARS-CoV-2 and lipids, as well as the consequences of these processes, is unknown. In addition, the long post-COVID-19 period has been confirmed in the majority of people who have suffered from COVID-19; therefore, additional attention should be paid to studying the biochemical parameters of lipid metabolism after SARS-CoV-2 infection. Our work is aimed the studying of lipid profile including concentration of total cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL), very low-density lipoproteins (VLDL) and triglycerides (TG) in donor groups who had suffered from COVID-19 and had different titers of anti-SARS-CoV-2 IgG in blood plasma. We selected donor groups with maximum and minimum changes of parameters among donor groups with titers of anti-SARS-CoV-2 IgG ≥ 10 Index (S/C), than we compared these groups to donor group with titer of anti-SARS-CoV-2 IgG 0 Index (S/C). We established that the donor group with titer of anti-SARS-CoV-2 95 ± 5 Index (S/C) was characterized by the maximum concentration of total cholesterol, LDL, VLDL, TG, while the donor group with titer of anti-SARS-CoV-2 IgG 75 ± 5 Index (S/C) was determined as the minimum concentration of total cholesterol, HDL, LDL. In addition, donor group with titer of anti-SARS-CoV-2 IgG 85 ± 5 Index (S/C) was described a lower concentration of VLDL and TG then in donors – 0 Index (S/C). These changes may be linked to a potential risk of cardiovascular disease (CVD). Our work can be useful for future research targeting the study of the changes in lipid metabolism during SARS-CoV-2 infection and in the development of the treatment of COVID-19 or laboratory diagnostics of physiological processes in the post-COVID-19 period.

Risk association of metabolites and immune response mediator indicators withthe occurrence of retained placenta in Murrah buffaloes (Bubalus bubalis)

This study was designed to investigate the risk association of metabolites and immune response mediator indicators with the occurrence of retained placenta (RP) in Murrah buffaloes (Bubalus bubalis). A total of six (n=6) healthy pregnant Murrah buffaloes and four (n=4) buffaloes suffering from RP were selected from the ICAR-NDRI cattle herd. Blood samples were collected from each healthy buffalo on days -56,-48,-42,-35,-28, -21, -14, -7, 0, +7, +14, +21, +28, +35, +35, +42, +48, +56 relative to calving. Blood samples were also collected from the buffaloes on the day of diagnosis of the RP as well as on an alternate day. The result revealed that plasma β-Hydroxybutyric acid (β-HBA)and nitric oxide (NO) levels were significantly (P&lt; 0.05) higher in buffaloes suffering from RP compared to normal parturient buffaloes. The level of IgG was significantly (P&lt;0.05) lowered in buffaloes suffering from RP (8.84±0.85 mg/mL) compared to normal parturient buffaloes (17.41±1.68 mg/mL). However, plasma Non-esterified fatty acids (NEFA), glucose, Blood Urea Nitrogen (BUN),calcium, Interleukin 6 (IL-6), and Total Antioxidant Activities(TAA) levels were non-significant differences between buffaloes suffering from RP and normal parturient buffaloes. A binary logistic regression assay revealed the positive association of postpartum β-HBA with RP (Odds ratio= 1.85). Overall results suggest that plasma β-HBA, IgG, and NO can be used as screening biomarkers during the transition period for the risk assessment of RP in buffaloes.

Detection of Plasma Antibodies Against CD25-Derived Peptide Antigens in Bladder Cancer.

Altered anti-CD25 antibody levels in plasma have been observed in patients with various solid malignancies. The present study aimed to determine whether circulating anti-CD25 antibody levels were altered in bladder cancer (BC). An enzyme-linked immunosorbent assay was developed in-house to detect plasma IgG antibodies against three CD25-derived linear peptide antigens in 132 patients with BC and 120 control subjects. The Mann-Whitney U-test indicated that the plasma levels of anti-CD25a (Z = -10.11, p < 0.001), anti-CD25b (Z = -12.79, p < 0.001), and anti-CD25c IgG (Z = -11.95, p < 0.001) were significantly lower in BC patients than in the control group. Further analysis indicated that the plasma levels of anti-CD25a IgG antibody were stage-dependent and associated with different postoperative histological grades (U = 977.5, p = 0.003). The receiver operating characteristic curve analysis showed that the area under the ROC curve (AUC) was 0.869 for anti-CD25a IgG (95%, 0.825 - 0.913), 0.967 for anti-CD25b IgG (95%, 0.945 - 0.988), and 0.936 for anti-CD25c IgG (95%, 0.905 - 0.967), with a sensitivity of 91.3% for the anti-CD25a IgG assay, 98.8% for the anti-CD25b IgG assay, and 96.7% for the anti-CD25c IgG assay, against a specificity of 95%. The present study suggests that circulating anti-CD25 IgG may have a potential predictive value for clinical staging and histological grading of BC.

Elevated Plasma Immunoglobulin Levels Prior to Heart Transplantation Are Associated with Poor Post-Transplantation Survival.

Cardiac allograft vasculopathy (CAV) and antibody-mediated rejection are immune-mediated, long-term complications that jeopardize graft survival after heart transplantation (HTx). Interestingly, increased plasma levels of immunoglobulins have been found in end-stage heart failure (HF) patients prior to HTx. In this study, we aimed to determine whether increased circulating immunoglobulin levels prior to transplantation are associated with poor post-HTx survival. Pre-and post-HTx plasma samples of 36 cardiac transplant recipient patients were used to determine circulating immunoglobulin levels. In addition, epicardial tissue was collected to determine immunoglobulin deposition in cardiac tissue and assess signs and severity of graft rejection. High levels of IgG1 and IgG2 prior to HTx were associated with a shorter survival post-HTx. Immunoglobulin deposition in cardiac tissue was significantly elevated in patients with a survival of less than 3 years. Patients with high plasma IgG levels pre-HTx also had significantly higher plasma levels after HTx. Furthermore, high pre-HTX levels of IgG1 and IgG2 levels were also significantly increased in patients with inflammatory infiltrate in CAV lesions. Altogether the results of this proof-of-concept study suggest that an activated immune response prior to transplantation negatively affects graft survival.

Long-term sialidase-specific immune responses after natural infection with cholera: Findings from a longitudinal cohort study in Bangladesh.

Immune responses that target sialidase occur following natural cholera and have been associated with protection against cholera. Sialidase is a neuraminidase that facilitates the binding of cholera toxin (CT) to intestinal epithelial cells. Despite this, little is known about age-related sialidase-specific immune responses and the impact of nutritional status and co-infection on sialidase-specific immunity. We enrolled 50 culture-confirmed Vibrio cholerae O1 cholera cases presenting to the icddr,b Dhaka hospital with moderate to severe dehydration. We evaluated antibody responses out to 18 months (day 540) following cholera. We assessed immune responses targeting sialidase, lipopolysaccharide (LPS), cholera toxin B subunit (CtxB), and vibriocidal responses. We also explored the association of sialidase-specific immune responses to nutritional parameters and parasitic co-infection of cases. This longitudinal cohort study showed age-dependent differences in anti-sialidase immune response after natural cholera infection. Adult patients developed plasma anti-sialidase IgA and IgG responses after acute infection (P<0.05), which gradually decreased from day 30 on. In children, no significant anti-sialidase IgA, IgM, and IgG response was seen with the exception of a late IgG response at study day 540 (p=0.05 compared to adults). There was a correlation between anti-sialidase IgA with vibriocidal titers, as well as anti-sialidase IgA and IgG with anti-LPS and anti-CtxB antibody responses in adult patients, whereas in children, a significant positive correlation was seen only between anti-sialidase IgA and CtxB IgA responses. Stunted children showed significantly lower anti-sialidase IgA, IgG, and IgM antibody responses and higher LPS IgG and IgM antibody responses than healthy children. The anti-sialidase IgA and IgG responses were significantly higher in cases with concomitant parasitic infection. Our data suggest that cholera patients develop age-distinct systemic and mucosal immune responses against sialidase. The stunted children have a lower anti-sialidase antibody response which may be associated with gut enteropathy and the neuraminidase plays an important role in augmented immune response in cholera patients infected with parasites.

Myristolated Serotonin 2A Receptor Peptide Promotes Long-Lasting Blood Pressure-Lowering and Reno protection in Hypertensive Rat Species.

The aim of the present study was to test whether conjugation of a synthetic peptide corresponding to a fragment of the second extracellular domain of the human serotonin 2A receptor substantially alters the in vivo pharmacodynamic blood pressure-lowering profile of the peptide in different hypertensive rat strains. Sertuercept (SCLLADDN) was synthesized and modified using pegylation or myristolation. The two different peptide conjugates were tested in male Zucker diabetic fatty rats for acute and long-lasting blood pressure-lowering effects following single intraperitoneal administration. The myristolated Sertuercept was administered intraperitoneally to female Zucker fatty and male spontaneously hypertensive rats (SHR) and blood pressure was monitored either using tail cuff measurement (female Zucker) or by telemetry (SHR) rats. Plasma immunoglobulin G obtained by Protein G affinity chromatography in 25-week-old female Zucker or male spontaneously hypertensive rats was tested for binding to a linear synthetic peptide corresponding to the second extracellular loop of the serotonin 2A receptor. A cohort of male Zucker diabetic fatty rats was randomized to seven weeks of once-weekly myristolated Sertuercept or scrambled peptide (injections) and the kidneys were examined histologically for differences in total kidney lesions or fibrosis. Pegylated Sertuercept promoted substantial blood pressure-lowering lasting approximately 30-48 hours in male Zucker diabetic fatty rats. Blood pressure-lowering following a single injection of Myristolated Sertuercept was much longer-lasting (6-11 days) and it was effective in male Zucker diabetic fatty rats, male spontaneously hypertensive rats and in a subset of hypertensive female Zucker fatty rats. Seven weeks' treatment with once-weekly Myristolated Sertuercept (2mg/kg) was associated with significantly fewer kidney lesions and less interstitial fibrosis compared to scrambled peptide in 25-week-old male Zucker diabetic fatty rats. Male spontaneously hypertensive rats (4 of 4 tested) harbored plasma IgG which bound significantly to serotonin 2A receptor peptide, and a subset of female Zucker fatty rats harboring IgG were responsive to blood pressure-lowering from the myristolated Sertuercept peptide. Myristolated-Sertuercept, an epitope-specific peptide comprised of a portion of second extracellular loop of the human serotonin 2A receptor was safe, well-tolerated and effectively lowered blood pressure for one week or longer in two different strains of male hypertensive rats. These data provide proof-of-concept that once-weekly systemic drug administration is feasible to achieve not only long-lasting hypertension control, but also substantial renoprotection.

Effects of maternal supplementation of fish oil during late gestation and lactation on growth performance, fecal microbiota structure and post-weaning diarrhoea of offspring piglets.

Homeostasis of gut microbiota is a critical contributor to growth and health in weaned piglets. Fish oil is widely reported to benefit health of mammals including preventing intestinal dysfunction, yet its protective effect during suckling-to-weaning transition in piglets remains undetermined. Low (30 g/d) and high (60 g/d) doses of n-3-rich fish oil were supplemented in sows from late gestation to lactation. Serum indicators and gut microbiota were determined to evaluate the effects of maternal fish oil on growth performance, immunity and diarrhea of piglets. DHA and EPA in the colostrum as well as serum of suckling and 1-week post-wean piglets were significantly and linearly increased by maternal supplementation of fish oil (P < 0.05). IGF1 and T3 in nursing and weaned piglets were significantly elevated by maternal fish oil (P < 0.05), and the increase of IGF1 was concerning the dosage of fish oil. Colostrum IgG, plasma IgG, IgM in suckling piglets, IgG, IgM and IgA in weaned piglets were significantly increase as maternal replenishment of fish oil increased (P < 0.05). Additionally, cortisol was significantly reduced in weaned pigs (P < 0.05), regardless of dosage. 16S rRNA sequencing revealed that α-diversity of fecal microbiota in nursery piglets, and fecal Lactobacillus genus, positively correlated with post-weaning IgA, was significantly increased by high dosage. Collectively, maternal fish oil during late pregnancy and lactation significantly promoted growth, enhanced immunity, and reduced post-weaning diarrhea in piglets, therefore facilitated suckling-to-weaning transition in piglets, which may be partially due to the altered gut microbial community.

Cross-sectional associations of maternal PFAS exposure on SARS-CoV-2 IgG antibody levels during pregnancy

BackgroundPerfluoroalkylated substances (PFAS) are man-made, persistent organic compounds with immune-modulating potentials. Given that pregnancy itself represents an altered state of immunity, PFAS exposure-related immunotoxicity is an important environmental factor to consider in SARS-CoV-2 infection during pregnancy as it may further affect humoral immune responses. AimTo investigate the relationship between maternal plasma PFAS concentrations and SARS-CoV-2 antibody levels in a NYC-based pregnancy cohort. MethodsMaternal plasma was collected from 72 SARS-CoV-2 IgG + participants of the Generation C Study, a birth cohort established at the beginning of the COVID-19 pandemic in New York City. Maternal SARS-CoV-2 anti-spike IgG antibody levels were measured using ELISA. A panel of 16 PFAS congeners were measured in maternal plasma using a targeted UHPLC-MS/MS-based assay. Spearman correlations and linear regressions were employed to explore associations between maternal IgG antibody levels and plasma PFAS concentrations. Weighted quantile sum (WQS) regression was also used to evaluate mixture effects of PFAS. Models were adjusted for maternal age, gestational age at which SARS-CoV-2 IgG titer was measured, COVID-19 vaccination status prior to IgG titer measurement, maternal race/ethnicity, parity, type of insurance and pre-pregnancy BMI. ResultsOur study population is ethnically diverse with an average maternal age of 32 years. Of the 16 PFAS congeners measured, nine were detected in more than 60% samples. Importantly, all nine congeners were negatively correlated with SARS-CoV-2 anti-spike IgG antibody levels; n-PFOA and PFHxS, PFHpS, and PFHxA reached statistical significance (p < 0.05) in multivariable analyses. When we examined the mixture effects using WQS, a quartile increase in the PFAS mixture-index was significantly associated with lower maternal IgG antibody titers (beta [95% CI] = −0.35 [-0.52, −0.17]). PFHxA was the top contributor to the overall mixture effect. ConclusionsOur study results support the notion that PFAS, including short-chain emerging PFAS, act as immunosuppressants during pregnancy. Whether such compromised immune activity leads to downstream health effects, such as the severity of COVID-19 symptoms, adverse obstetric outcomes or neonatal immune responses remains to be investigated.

Characterization of a Novel CD4 Mimetic Compound YIR-821 against HIV-1 Clinical Isolates.

Small CD4-mimetic compound (CD4mc), which inhibits the interaction between gp120 with CD4, acts as an entry inhibitor and induces structural changes in the HIV-1 envelope glycoprotein trimer (Env) through its insertion within the Phe43 cavity of gp120. We recently developed YIR-821, a novel CD4mc, that has potent antiviral activity and lower toxicity than the prototype NBD-556. To assess the possibility of clinical application of YIR-821, we tested its antiviral activity using a panel of HIV-1 pseudoviruses from different subtypes. YIR-821 displayed entry inhibitor activity against 53.5% (21/40) of the pseudoviruses tested and enhanced neutralization mediated by coreceptor binding site (CoRBS) antibodies in 50% (16/32) of these. Furthermore, when we assessed the antiviral effects using a panel of pseudoviruses and autologous plasma IgG, enhancement of antibody-mediated neutralization activity was observed for 48% (15/31) of subtype B strains and 51% (28/55) of non-B strains. The direct antiviral activity of YIR-821 as an entry inhibitor was observed in 53% of both subtype B (27/51) and non-B subtype (40/75) pseudoviruses. Enhancement of antibody-dependent cellular cytotoxicity was also observed with YIR-821 for all six selected clinical isolates, as well as for the transmitted/founder (T/F) CH58 virus-infected cells. The sequence diversity in the CD4 binding site as well as other regions, such as the gp120 inner domain layers or gp41, may be involved in the multiple mechanisms related to the sensitive/resistant phenotype of the virus to YIR-821. Our findings may facilitate the clinical application of YIR-821. IMPORTANCE Small CD4-mimetic compound (CD4mc) interacts with the Phe43 cavity and triggers conformational changes, enhancing antibody-mediated neutralization and antibody-dependent cellular cytotoxicity (ADCC). Here, we evaluated the effect of YIR-821, a novel CD4mc, against clinical isolates, including both subtype B and non-B subtype viruses. Our results confirm the desirable properties of YIR-821, which include entry inhibition, enhancement of IgG-neutralization, binding, and ADCC, in addition to low toxicity and long half-life in a rhesus macaque model, that might facilitate the clinical application of this novel CD4mc. Our observation of primary viruses that are resistant to YIR-821 suggests that further development of CD4mcs with different structural properties is required.

Developmental Changes of Immunity and Different Responses to Weaning Stress of Chinese Indigenous Piglets and Duroc Piglets during Suckling and Weaning Periods

To investigate developmental changes in immunity and different responses to weaning stress of piglets from different breeds during suckling and weaning periods, a total of 30 litters of Taoyuan black (TB) piglets, Xiangcun black (XB) piglets, and Duroc (DR) piglets (ten litters per breed) were selected at 1, 10, 21, and 24 days of age, respectively. The results showed that the liver index of TB piglets was higher at 10 days of age than that of the other days of age and breeds. Regardless of the days of age, TB and XB piglets had a higher plasma IgA level and lower ileal IgM level than in the DR piglets, and XB piglets had a lower plasma IgG level than the other breeds. TB and XB piglets had a higher IL-6 level and lower IL-17 level in plasma at 24 days of age than DR piglets, regardless of the days of age. The ileal levels of IL-2, IL-10, IFN-γ, and TNF-α were lower in the TB and XB piglets at 24 days of age than in the DR piglets. The ileal expression levels of IRAK1, CD14, MyD88, and NF-κB were down-regulated in the TB and XB piglets at 24 days of age compared to those in the DR piglets. These findings suggest that there were differences in the development of immune function among different pig breeds. Moreover, TB and XB piglets presented stronger resistance to weaning stress than the DR piglets, which may be related to the immune regulation mediated by the MyD88/NF-κB signaling pathway.

Altered Fc glycosylation of anti‐HLA alloantibodies in hemato‐oncological patients receiving platelet transfusions

BackgroundThe formation of alloantibodies directed against class I human leukocyte antigens (HLA) continues to be a clinically challenging complication after platelet transfusions, which can lead to platelet refractoriness (PR) and occurs in approximately 5%–15% of patients with chronic platelet support. Interestingly, anti‐HLA IgG levels in alloimmunized patients do not seem to predict PR, suggesting functional or qualitative differences among anti‐HLA IgG. The binding of these alloantibodies to donor platelets can result in rapid clearance after transfusion, presumably via FcγR‐mediated phagocytosis and/or complement activation, which both are affected by the IgG‐Fc glycosylation. ObjectivesTo characterize the Fc glycosylation profile of anti‐HLA class I antibodies formed after platelet transfusion and to investigate its effect on clinical outcome. Patients/MethodsWe screened and captured anti‐HLA class I antibodies (anti‐HLA A2, anti‐HLA A24, and anti‐HLA B7) developed after platelet transfusions in hemato‐oncology patients, who were included in the PREPAReS Trial. Using liquid chromatography‐mass spectrometry, we analyzed the glycosylation profiles of total and anti‐HLA IgG1 developed over time. Subsequently, the glycosylation data was linked to the patients' clinical information and posttransfusion increments. ResultsThe glycosylation profile of anti‐HLA antibodies was highly variable between patients. In general, Fc galactosylation and sialylation levels were elevated compared to total plasma IgG, which correlated negatively with the platelet count increment. Furthermore, high levels of afucosylation were observed for two patients. ConclusionsThese differences in composition of anti‐HLA Fc‐glycosylation profiles could potentially explain the variation in clinical severity between patients.

Persistence of envelopes in different CD4+ T-cell subsets in antiretroviral therapy-suppressed people with HIV.

Despite suppressive antiretroviral therapy (ART), HIV can persist in a diverse range of CD4+ T-cell subsets. Through longitudinal env sampling from people with HIV (PWH) on ART, we characterized the persistence and phenotypic properties of HIV envs over two time-points (T1 and T2). Longitudinal blood and lymphoid tissue samples were obtained from eight PWH on suppressive ART. Single genome amplification (SGA) was performed on env to understand the genetic diversity and degree of clonal expansions over time. A subset of envs were used to generate pseudovirus particles to assess sensitivity to autologous plasma IgG and broadly neutralizing antibodies (bNAbs). Identical env sequences indicating clonal expansion persisted between T1 and T2 and within multiple T-cell subsets. At both time-points, CXCR4-tropic (X4) Envs were more prevalent in naive and central memory cells; the proportion of X4 Envs did not significantly change in each subset between T1 and T2. Autologous purified plasma IgG showed variable neutralization of Envs, with no significant difference in neutralization between R5 and X4 Envs. X4 Envs were more sensitive to neutralization with clinical bNAbs, with CD4-binding site bNAbs demonstrating high breadth and potency against Envs. Our data suggest the viral reservoir in PWH on ART was predominantly maintained over time through proliferation and potentially differentiation of infected cells. We found the humoral immune response to Envs within the latent reservoir was variable between PWH. Finally, we identified coreceptor usage can influence bNAb sensitivity and may need to be considered for future bNAb immunotherapy approaches.

Observation of hapten-induced sensitization responses for the development of a mouse skin sensitization test, including the elicitation phase

The only official method that can detect the skin sensitizing potential of chemicals, including the elicitation response, is the OECD test guideline (TG) 406. However, this guideline uses guinea pigs, which requires complex procedures. Since a simple and complete test method for evaluating skin sensitization is needed, especially for mechanistic studies of skin sensitization, this study confirmed the reactivity of mice to skin sensitizing substances. We set up a protocol involving one induction exposure of the test substance to the back skin, followed by three challenge exposures to the auricle (Protocol 2), and compared their skin sensitization responses with the results of two exposures to the auricle and back skin every 2 weeks (Protocol 1) and a local lymph node assay (TG442B). A hapten 2,4-dinitrofluorobenzene caused significant auricular thickening, skin inflammation, and enlarged auricular lymph nodes in Protocols 1 and 2. These changes were more pronounced in Protocol 2. Plasma IgE and IgG1 and gene expression of IL4, IFNγ, and perforin were significantly increased in Protocol 2. Cell proliferation in the auricular lymph nodes was observed in both protocols as in TG442B. These results indicate that Protocol 2 can be a good candidate for a relatively simple skin sensitization test.

NNV024, a Humanized Anti-CD37 Antibody with Enhanced ADCC and Extended Plasma Half-Life for the Treatment of B-Cell Malignancies

Background: There is a significant unmet clinical need for new therapeutic approaches for patients with B-cell non-Hodgkin lymphomas (B-NHL) who relapse or are refractory to anti-CD20 therapies. Moreover, certain B-cell malignancies do not express CD20. High expression of the CD37 antigen on malignant B-cells associated with limited or no expression on other hematopoietic cells makes CD37 a highly attractive alternative target for B-cell depleting therapies. We have therefore developed a humanized anti-CD37 monoclonal antibody (NNV024) engineered to exhibit a strong antibody-dependent cellular cytotoxicity (ADCC). Methods: Generation of NNV024 was performed by combining in silico CDR-grafting and structure-based back mutation. Candidates were then selected for their affinity to CD37 expressing cell line, Ramos. In silico immunogenicity prediction tools were integrated in the selection process to support the generation of a candidate with low immunogenicity potential (NNV023). Last, to increase ADCC, the selected candidate was afucosylated at the N-linked bi-antennary glycan at N297 of the Fc region (NNV024). The NNV024 was characterized in vitro and in vivo. Binding to human Fc gamma receptors (FcγRs), neonatal Fc receptor (FcRn), and complement component 1q (C1q) was confirmed by ELISA and SPR. ADCC and antibody-dependent cellular phagocytosis (ADCP) induction were measured using cell-based reporter assays with eleven cell lines derived from B-NHL subtypes such as Burkitt's lymphoma, diffuse large B-Cell lymphoma (DLBCL), and mantel cell lymphoma (MCL). All cell lines express both CD20 and CD37 on their cell surface. In addition, B cell chronic lymphocytic leukaemia (B-CLL) cells isolated from patient samples were used to test induction of ADCC, ADCP and complement-dependent cytotoxicity (CDC) in vitro. NNV024 plasma pharmacokinetics were assessed in Tg32 transgenic mice expressing human FcRn, which is considered a key regulator of IgG plasma half-life. A therapy study comparing NNV024 (n=10) and obinutuzumab (n=10) was performed using a disseminated tumor (Daudi) model in CB17-SCID mice (107 cells/mouse, i.v.). The anti-CD20 Abs rituximab and obinutuzumab as well as the anti-CD37 Ab, Duohexabody-CD37, were used for benchmarking. Results: As expected, the glyco-engineering increased affinity of NNV024 to FcγRIIIa (KD before afucosylation: 460.8 ng/mL; KD after: 104.1 ng/mL). Binding of Abs to FcγRIIIa activates immunological effector cells such as Natural Killer cells, macrophages, monocytes, and eosinophils. NNV024 demonstrated ADCC superior to that observed with obinutuzumab, rituximab, and Duohexabody-CD37. NNV024 exhibited a 2-fold prolonged plasma half-life in mice (8.9±0.8 days) compared to obinutuzumab (4.4±1.3 days) and Duohexabody-CD37 (4.1±1.2 days). Mice survival was enhanced up to ~ 40% when treated with NNV024 (10 µg/mouse - 70.5 days; 50 µg/mouse - 84 days) compared to obinutuzumab at a dose of 10 µg (70.5 days vs. 53 days) or 50 µg (84 days vs. 62 days). Conclusion: These encouraging preclinical results support further development of NNV024 as a potential therapeutic mAb candidate for the treatment of B-cell malignancies and B-cell driven autoimmune disorders.

Heterologous booster with inhaled adenovirus vector COVID-19 vaccine generated more neutralizing antibodies against different SARS-CoV-2 variants

ABSTRACT The rapid widespread Omicron subvariant BA.5 of SARS-CoV-2 has become a potential imminent pandemic threat, but available vaccines lack high efficacy against this subvariant. Thus, it is urgent to find highly protective vaccination strategies within available SARS-CoV-2 vaccines. Here, by using a SARS-CoV-2 pseudovirus neutralization assay, we demonstrated that the aerosol inhalation of adenoviral vector COVID-19 vaccine after two dose of inactivated vaccine (I-I-Ad5) led to higher levels of neutralizing antibodies against D614G strain (2041.00[95% CI, 1243.00–3351.00] vs 249.00[149.10–415.70]), Omicron BA.2 (467.10[231.00–944.40] vs 72.21[39.31–132.70]), BA.2.12.1(348.5[180.3–673.4] vs 53.17[31.29–90.37]), BA.2.13 (410.40[190.70–883.3] vs 48.48[27.87–84.32]), and BA.5 (442.40 vs 56.08[35.14–89.51]) than three inactivated vaccine doses (I-I-I). Additionally, the level of neutralizing antibodies against BA.5 induced by I-I-Ad5 was 2.41-fold higher than those boosted by a third dose of RBD subunit vaccine (I-I-S) (p = 0.1308). The conventional virus neutralizing assay confirmed that I-I-Ad5 induced higher titre of neutralizing antibodies than I-I-I (116.80[84.51–161.5] vs 4.40[4.00–4.83]). In addition, I-I-Ad5 induced higher, but later, anti-RBD IgG and IgA in plasma than I-I-I. Our study verified that mucosal immunization with aerosol inhalation of adenoviral vector COVID-19 vaccine may be an effective strategy to control the probable wave of BA.5 pandemic in addition to two inactivated vaccines.