IgG Levels Research Articles

Safety and Immunogenicity of Intranasal Razi Cov Pars as a COVID-19 Booster Vaccine in Adults: Promising Results from a Groundbreaking Clinical Trial

Protective antibodies in the upper respiratory tract prevent the spread of COVID-19 in the community. Intranasal vaccines could raise the specific secretory IgA and IgG levels. This is a single-center, randomized, double-blind, placebo-controlled clinical trial to evaluate the safety and immunogenicity of Razi Cov Pars (RCP) intranasal recombinant protein subunit COVID-19 vaccine as a booster in adults. We compared specific IgG and IgA levels in the intranasal RCP group (n = 97) versus placebo (n = 96) in serum, saliva, and nasal mucosal secretions on days 0 and 14 and reported their Geometric Mean Ratios (GMR) and 95% confidence intervals (CI). We showed significant increases in IgA and IgG anti-RBD in the nasal mucosa in the RCP group, but their increase was not detectable in the serum and saliva. Anti-spike IgA in the nasal mucosa also increased in the RCP group compared to the placebo. This increase against the COVID-19 variant Omicron was also similar to that of the Wuhan. We detected no serious adverse reactions or anaphylaxis and all adverse events resolved completely during the follow-up period and were similar in both groups. Intranasal RCP is safe, stimulates the respiratory mucosal immunity, and could be a booster on various COVID-19 vaccines and be effective against new virus variants.

Use of serum-free media for peripheral blood mononuclear cell culture and the impact on T and B cell readouts

IntroductionAs part of a wider programme of work developing next-generation risk assessment approaches (NGRA) using non-animal methods (NAMs) for safety assessment of materials, Unilever SEAC is exploring the use of a peripheral blood mononuclear cell (PBMC) system to investigate how cells from different arms of the human immune system are impacted by different treatments. To maximise human relevance, the cell cultures are supported by human serum, but this came with some challenges, including an inability to measure induced levels of immunoglobulins due to high background levels. Therefore, a study comparing use of human sera containing media with three different chemically defined serum-free media was undertaken.Materials and MethodsPBMC were isolated from healthy donors and cultured in the absence (media alone) or presence of stimulation reagents (CpG-ODN plus IL-15, Pokeweed Mitogen (PWM) or Cytostim (CS)), in RPMI plus human serum, AIM-V, CTS OpTmizer T cell expansion SFM or X-VIVO 15 media. T cell (CD4+ and CD8+) and B cell proliferation and viability were measured after 6 days, along with levels of total IgG in the cell culture supernatants.ResultsEach of the serum-free media tested supported good levels of viable and proliferating T cells and B cells over the 6 days of culture, with only a few, small differences across the media, when there was no stimulation. They also enabled detection of a stimulation-evoked increase in IgG levels. There were however some differences in the viability and proliferation responses of T and B cells, to different stimuli, across the different media.DiscussionThe serum-free media formulations tested in this study offer defined systems for. measuring B cell IgG responses, in vitro, in either a ‘T cell-independent’ (CpG + IL-15) or “T cell-dependent” (PWM or CS) manner and for assessing B cell proliferation, particularly in response to a “T cell-independent” stimulus. However, there are some characteristics and features endowed by human serum that appear to be missing. Therefore, further work is required to optimise animal-free, chemically defined culture conditions for PBMC based assays for inclusion in tiered safety assessments.

Neutrophil-activating protein in Bacillus spores inhibits casein allergy via TLR2 signaling

BackgroundMilk allergy commonly occurs in children, mainly caused by bovine-derived casein (CAS) protein. Neutrophil-activating protein (NAP) of Helicobacter pylori plays an immunomodulatory role with potential to suppress Th2-type immune responses. Bacillus subtilis (B. subtilis) spores are commonly used as oral vectors for drug delivery.ObjectiveTo investigate whether recombinantly expressed NAP on B. subtilis spores could be an effective treatment for CAS allergy in mouse.MethodsAfter CAS sensitization, mice were orally administered B. subtilis spores expressing recombinant NAP for 6 weeks. Allergic symptoms and parameters were evaluated after CAS challenge oral gavage, including allergic inflammation, splenic cytokines, and serum-specific antibodies. Protein levels of Toll-like receptor 2 (TLR2) and c-JUN in the jejunum tissue were measured by western blot. Bone marrow-derived macrophages (BMDMs) were stimulated with inactivated NAP spores to measure the influence on cytokine profiles in vitro.ResultsNAP recombinant spore treatment significantly reduced allergic symptoms and intestinal inflammation. Interleukin-12 and interferon-gamma levels increased, whereas serum CAS-specific IgG1 and IgE levels decreased. TLR2 and c-JUN expression levels were elevated in the jejunal tissue. Inactivated NAP spores polarized BMDMs to the M1 phenotype and enhanced cytokine expression, which were inhibited by a TLR2 neutralizing antibody.ConclusionNAP offers a new strategy in the treatment of CAS allergy by inhibiting the Th2 response, while eliciting macrophages to promote Th1 immune responses.

Seroprevalence and prognostic value of Aspergillus-specific IgG among non-neutropenic invasive pulmonary aspergillosis patients: a prospective multicenter study

BackgroundThis study aimed to assess the diagnostic and prognostic value of Aspergillus-specific IgG (Asp-IgG) for invasive pulmonary aspergillosis (IPA) in non-neutropenic non-hematologic patients.MethodsBetween November 2019 and February 2022, we recruited 40 non-neutropenic, non-hematologic IPA patients from Taiwan and measured serum Asp-IgG levels using Phadia, Thermofisher. A positive Asp-IgG test was defined as a level > 40 mgA/L. We evaluated the association between Asp-IgG levels and overall survival, as well 90-day mortality rate of IPA patients.ResultsOf the 40 participants, 11 (27.5%) tested positive for Asp-IgG, while 16 (40%) had positive galactomannan antigen (optical density > 1). Higher Asp-IgG levels were associated with improved overall survival (HR: 0.22, 95% CI: 0.05–0.99, p = 0.035) in multivariable Cox regression. The overall 90-day mortality rate was 65% (26/40). We found that patients with low Asp-IgG levels (≤ 40 mgA/L) had a borderline higher 90-day mortality rate compared to patients with high Asp-IgG levels (OR: 3.15, 95% CI: 0.75–13.28, p = 0.118). Stratifying by serum galactomannan and Aspergillus IgG levels, patients with elevated serum GM and low Asp-IgG had the highest 90-day mortality (80%, 8/10), followed by patients with low serum GM and low Asp-IgG (68.4%, 13/19).ConclusionsAsp-IgG was positive in approximately one-fourth of non-neutropenic IPA patients. Asp-IgG may hold potential as a clinical prognostic factor for IPA. Further studies are required to validate this finding.

Association of the humoral immune response with the inflammatory profile in Plasmodium vivax infections in pregnant women.

Plasmodium vivax infection, when it occurs during pregnancy, has often been associated with serious adverse pregnancy outcomes. However, immunological alterations in pregnancy and their consequences have been little explored. We characterized the humoral immune response in pregnant women exposed to malaria by P. vivax antigens and its association with the maternal inflammatory profile and poor pregnancy outcomes. An observational cohort study in the Brazilian Amazon was conducted between 2013 and 2015. After applying exclusion criteria, 242 mother-child pairs were included in the analysis. Data on maternal infection, gestational outcomes, and inflammatory factors were evaluated in the maternal peripheral plasma. In samples from the first infection, the presence of total IgG and its subclasses in plasma against PvMSP119 protein were also quantified. Previous exposure to malaria, observed by anti-total IgG antibodies to the PvMSP119 antigen, increased the inflammatory response to infection when the pregnant woman had malaria during pregnancy. IL-6 and IL-10 levels were positively correlated with parasitemia and with total IgG levels; but they were negatively correlated with the gestational age at delivery from Pv-infected woman. In multivariate linear regression analyses, IgG 1, 2 and 4 was negatively and positively associated with cytokines IL-6 and IL-10, respectively, in P. vivax-infection. An association between the humoral immune response and the peripheral inflammatory cytokine profile with the adverse outcomes in malaria in pregnancy by P. vivax was observed. Previous exposure to the parasite can influence the IL-6 and IL-10 response, which is associated with increased parasitemia, reduced maternal weight gain and premature delivery.

Diphencyprone reduces the CD8+ lymphocytes and IL-4 and enhences IgG2a/IgG1 ratio in pathogenicity of acute leishmania major infection in BALB/c mice

BackgroundThe exact role of different immune cells and cytokines in control or promotion of intracellular growth of leishmania has still remained a controversial topic. The aim of the present study was to study effects of cellular changes and relevant cytokines in cell mediated immunity by diphencyprone (DCP) in pathogenicity of acute L.major infection in BALB/c mice. Methods45 healthy female BALB/c mice were injected with L. major promastigotes under the base of tail. The mice were randomly divided to three groups of 15 mice: (1) control group without any treatment. (2) acetone group: Acetone was applied topically on the cutaneous lesions weekly and (3) DCP group: DCP was applied topically on the cutaneous lesions with increasing concentrations to induce local allergy. The mice were followed by the end of eighth week, and then macroscopic changes, histopathology, immunology studies, and organ parasite burden were determined. ResultsIn DCP group, in comparison to other groups the ulcer size and parasite burden in ulcer site and spleen increased, significantly. There was a deep lymphohistiocytic infiltration in the ulcer site. Total IgG, IgG1, and IgG2a levels as well as IgG2a/IgG1 ratio and intracellular IFN-gamma in CD8+ lymphocytes were significantly higher. IL4 and T CD8+ lymphocytes were significantly lower in DCP group. The IgG2a/IgG1 ratio was more than 1 in all groups. ConclusionOur findings demonstrated that DCP reduced the CD8+ lymphocytes and IL-4 production. In spite of increased IgG2a/IgG1 ratio, the parasite burden and inflammation severity increased in infected mice. The results can show the pivotal role of CD8+ lymphocytes in conjunction with Th1 lymphocytes in the control of acute leishmania infection in mice.

Patients with IgA Nephropathy Show Abnormal Frequencies of B cell Subsets and Unconventional T Cells and High Levels of Gd-IgA1 Coated Gut Bacteria

BackgroundMucosal inflammation is involved in the pathophysiology of Immunoglobulin-A nephropathy (IgAN), but peripheral immune phenotype analyses of IgAN patients often do not include unconventional T cells, the major subset in mucosal immunity. MethodsWe measured serum total IgA, gd-IgA1, secretory IgA, B cell activating factor (BAFF), and A proliferation-inducing ligand (APRIL) in 66 IgAN patients and 30 healthy controls (HC). We also quantified total IgA and gd-IgA1 in stool supernatant and coated on bacteria. In 35 patients and 14 controls, we performed extensive phenotyping (CyTOF) of circulating immune cells, including unconventional T cells [mucosal associated invariant T (MAIT) cells, γδ T, and NK T cells]. The results were validated using RNAseq data from a larger cohort of 179 patients with IgAN, 140 patients with minimal change disease (MCD), and 91 HC. ResultsIgAN patients had higher circulating levels of total IgA, gd-IgA1, and APRIL and higher IgA- and gd-IgA1-coated gut bacteria than controls, while serum levels of secretory IgA and BAFF did not differ between groups. IgAN patients showed more class switched memory and double negative B cells than controls. MAIT cells and γδ T cells were significantly lower, and CD4- CD8- NK T cells significantly higher in IgAN patients than in HC. We validated the significant decrease in MAIT cells in an independent cohort of patients with IgAN. ConclusionThe data indicate that patients with IgAN have increased circulating class switched memory and double negative B cells associated with abnormal T cell immunity, involving defects in unconventional T cell frequency. This may suggest putative alterations at mucosal sites due to cell migration leading to altered IgA production.

Epitope profiling of cow's milk allergen-specific antibodies with determining IgE content in epitopes-ALL, a 14-epitopes mixture

Allergen-specific antibodies (Abs), IgE, and IgG4 increase during the early phase of oral immunotherapy (OIT) of allergen food in patients; subsequently, IgE levels decrease and specific IgG4 levels increase after successful OIT treatment. The detailed profile of these Abs during OIT remains largely unclear. We developed a diagnostic tool to assess the OIT efficacy and extent of responsiveness based on a profiling method by identifying epitopes recognized by the Ab classes of IgE or IgG4.A peptide microarray followed by microplate analysis using synthetic peptides was used to identify 14 epitopes widely recognized by IgE and/or IgG4 in the serum samples of patients with OIT among the amino acid sequences of five major cow's milk allergens. The set of defined 14 epitopes clarified different epitope profiles of allergen-specific IgE and IgG4 in each patient's serum samples. Moreover, the total signal of Abs recognizing all 14 epitopes was equal to the sum of all individual epitope-specific Abs. It was further observed that the quantitative value of IgE concentrations of 14 epitopes-ALL correlated with the ImmunoCAP IgE value.These findings strongly imply that the quantity of IgE and IgG4 recognizing epitopes-ALL may easily be used to measure allergy severity. To investigate this potential, we developed an immunochromatographic method that can detect IgE and IgG4 levels in patient samples.This study clearly demonstrated the usefulness of the defined 14 epitopes and their mixture, “epitopes-ALL,” and that the simple and reliable methods of immunochromatography and microplate analyses demonstrating the epitope profile of allergen-specific Abs are applicable for diagnostic use at multiple disease stages and the OIT-treatment course in patients with cow's milk allergy.

Baseline Epitope-Specific IgE Profiles are Predictive of Sustained Unresponsiveness or High Threshold One-Year Post OIT in the POISED Trial

BackgroundResults from the POISED trial suggest that discontinuation of peanut oral immunotherapy can increase the risk of regaining clinical reactivity to peanut. ObjectiveWe sought to determine whether those who achieved sustained unresponsiveness (SU) or sustained high threshold (SHT) have different baseline sequential epitope-specific (es-) IgE profiles than those who achieved transient desensitization (TD). MethodsSubjects in the POISED trial (NCT02103270) were randomized to peanut (n=95) or placebo (n=25) for 24 months. OIT-desensitized subjects were then assigned to no peanut (PN-0, n=51) or 300mg (PN-300, n=30) for 12 months. SU and SHT were determined by those in PN-0 and PN-300, respectively, passing 4000mg peanut oral challenge. Specific IgE and IgG4 levels to peanut, Ara h 1-3 proteins and 64 allergenic epitopes were measured. We developed machine learning glmnet models with bootstrap simulations using baseline data to predict SU/SHT. ResultsEighty (84%) subjects were desensitized to peanut. Of those, 13% (n=8) and 37% (n=13) achieved SU/SHT in PN-0 and PN-300. Decreases in epitope-and protein-specific IgE levels and increases in IgG4 levels were observed during 2 years of OIT. At baseline, patients with SU in Peanut-0 but not Peanut-300 had lower es-IgE and protein-sIgE levels compared to the TD group. A machine-learning model with 12 baseline es-IgEs and age could predict SU/SHT with an accuracy of 94%, AUC 0.97, Sensitivity 1.00, Specificity 0.91. ConclusionsPatients who achieved SU/SHT have different baseline protein-and epitope-specific IgE profiles than those with TD. These profiles may help identify patients with an increased likelihood of achieving SU/SHT.

Low-dose interleukin-2 in birch pollen allergy: a phase-2 randomized double-blind placebo-controlled trial

Regulatory T cells (Tregs) are pivotal in immune tolerance to allergens. Low-dose IL-2 (IL-2LD) activates Tregs. To assess IL-2LD efficacy for controlling clinical responses to allergen exposures. RHINIL-2 was a phase-2a, randomised, double-blind, placebo-controlled trial. Patients with allergic rhinitis to birch pollen (BP) were included, 66% having concomitant asthma. All had a total nasal symptom score (TNSS) ≥5 following nasal exposure to BP in an environmental-exposure-chamber (EEC). Patients received 1 MUI/day of IL-2 (n=12) or Placebo (n=12) for 5 days, followed by weekly injections for 4 weeks. Clinical responses to subsequent BP exposures in the EEC were evaluated using TNSS, the rhinitis visual analogue scale (VAS) and spirometry. The primary efficacy endpoint was the difference in TNSS area under the curve between inclusion and day 40 (TNSSΔAUC). IL-2LD treatment induced a significant expansion of Tregs. The TNSSΔAUC in the IL-2 and Placebo groups was non significantly different. TNSS and VAS AUCs were significantly reduced from baseline to day 40 in the IL-2LD group only (p=0.04 and p=0.01, respectively). The ratio of forced expiratory volume in 1 second/forced vital capacity (FEV1P) and the forced mid-expiratory flow (FEF25-75%) showed improvement in the IL-2LD vs Placebo groups at day 40 (p=0.04 and 0.04, respectively). However, the short treatment duration used in this study cannot have effects on specific IgE or IgG4 levels given their half-life. There was no severe treatment-related adverse events. IL-2LD is well-tolerated in allergic patients, even with asthma, clearing the path for further therapeutic development. Our work suggests that Treg can safely attenuate an ongoing allergic response. It paves the way for larger studies with longer treatment periods, which are needed to properly evaluate the therapeutic potential of IL-2 in allergy.

Which accessible clinical features and laboratory findings might predict methotrexate success in children with juvenile idiopathic arthritis in Bosnia and Herzegovina?

<p><strong>Aim</strong> To determine whether demographic data, clinical features, and laboratory variables at disease onset can predict the response to methotrexate in juvenile idiopathic arthritis (JIA) patients. <br /><strong>Methods</strong> A cohort of 143 newly diagnosed JIA patients initially treated with methotrexate was enrolled in this study. Demographic, clinical, and laboratory parameters were analysed using univariate and multivariate logistic regression to identify predictors of response to methotrexate. The variables included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelets, IgA, IgG, the number of active joints and age at disease onset. Treatment response was assessed at six months, with patients classified as responders (those who achieved clinically inactive disease according to the American College of Rheumatology - ACR criteria) or non-responders. <br /><strong>Results</strong> Poor response to methotrexate was associated with the number of active joints (p=0.0001; OR=2.7), baseline levels of CRP (p=0.044; OR=1.138), IgA (p =0.004; OR=2.159), and platelet count (p=0.01; OR=1.05). IgG level (P=0.236) did not correlate with the treatment response. <br /><strong>Conclusion</strong> We identified widely available and clinically acceptable biomarkers that can be utilized as predictive indicators of response to methotrexate in JIA patients.</p>

Induction of an 11 KDA Protein Epitope For Reducing Mrsa Bacterial Colony Counts Via Cellular and Humoral Adaptive Immune Responses In Postpartum MUS Musculus Infected With MRSA: A Strategy for Enhancing Public Health and Combating Antibiotic Resistance

Objective: This study investigates how the 11 kDa protein epitope, from the cross-reaction between MRSA bacteria and L. reuteri, reduces MRSA colonies through adaptive immune responses (Th17, Th2), cytokines (IL-4, IL-22), and innate immunity (IgG antibodies) in postpartum Mus musculus. Method: A true experimental design was applied using Balb/c mice divided into seven groups, including controls and those treated with different combinations of L. reuteri, MRSA proteins, and peptides. Cellular immunity (Th17, Th2), cytokines (IL-4, IL-22), IgG antibodies, and MRSA colonies were measured post-treatment. Results & Discussion: The candidate vaccine enhanced cellular adaptive immunity (Th2, Th17), cytokine responses (IL-4, IL-22), and reduced MRSA colonies. IgG levels were notably higher in Groups K3 and K6 compared to K1. Conclusion: The 11 kDa protein epitope, from the MRSA-L. reuteri cross-reaction, effectively modulates adaptive immunity, reducing MRSA colonies in postpartum Mus musculus.

The immune responses elicited by six recombinant antigens of Mycoplasma hyopneumoniae in mice

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causative agent of swine enzootic pneumonia, resulting in substantial economic losses in global pig farming. Although vaccination is the primary strategy for controlling M. hyopneumoniae infection, current vaccines fall short in preventing transmission of this pathogen or protecting the body from secondary infection. This study aimed to assess the immunogenicity of six recombinant antigens (P97R1, P46, GAPDH, PdhA, DnaK, and EF-Tu) of M. hyopneumoniae through intramuscular immunization in mice. The results showed that the six antigens elicited high levels of serum IgG. Among them, P97R1, P46, PdhA, and DnaK stimulated robust antigen-specific IgA mucosal immune responses. CCK-8 assays revealed that both P97R1 and DnaK significantly increased the proliferation of mononuclear cells from spleen and lung, and DnaK also promoted the proliferation of blood mononuclear cells. Additionally, PdhA induced Th17-type immune response with a high level of IL-17 level in serum. Flow cytometry analysis indicated that P97R1 and PdhA increased the ratio of CD8+/CD4+ T lymphocyte, favoring cytotoxic T lymphocyte (CTL) immune responses. Notably, P97R1 immunization significantly decreased the percentages of CD4+ T cells while increased the percentages of CD8+ T cells. The present findings demonstrate that the candidate antigens P97R1, PdhA, and DnaK of M. hyopneumoniae induce specific humoral and mucosal immunity; P97R1 and DnaK also stimulated intense cellular immunity, and PdhA induced CTL and Th17-type immune responses. In conclusion, P97R1, PdhA, and DnaK emerge as potential candidate antigens for the future development of a more effective subunit vaccine against M. hyopneumoniae.

NK cell membrane/MnO2 hybrid nanoparticle-adjuvanted intranasal vaccines synergistically boost protective immunity against H1N1 influenza infection

Intranasal vaccines hold a huge promise for preventing influenza infection, however, their development is compromised due to mucosal barriers and limited systemic and mucosal immunity. Herein, a novel biomimetic nano-adjuvant based on NK cell membrane (MNK)/MnO2 hybrid nanoparticles (NLipoMn) was developed for intranasal administration of H1N1 inactivated influenza vaccine (IIV). NK cell membrane, served as TLR4 agonist was fused with cationic liposomes encapsulating STING agonist MnO2 NPs (LipoMn) to yield NLipoMn, which inherited versatile characteristics to prolong the nasal retention of IIV. Encouragingly, CCL20 secretion was enhanced by NLipoMn-activated the TLR4/NF-κB pathway in mucosal endothelial cells, thereby promoting submucosal dendritic cells (DCs) recruitment for IIV uptake. Moreover, NLipoMn-IIV synergistically harnessed TLR4 and STING signaling pathway to augment STING activation though NLipoMn-activated the TLR4/NF-κB pathway, which demonstrated a superiority to elicit strong DCs maturation, CD8+ T cells activation, and high levels of antigen-specific IgG, antigen-specific IgA, cytokines secretion, resulting in a robust systemic and mucosal immune responses. Notably, intranasal immunization with NLipoMn-IIV elicited an effective immune protection against homologous and heterologous H1N1 influenza virus infection. This study provides a promising adjuvant candidate to develop needle-free intranasal vaccines that are active against influenza and other respiratory viral infection.

T. Muris Infection Dynamics of a Fresh, Wild Isolate: Is the Established E Isolate Still Relevant?

For decades, parasitic worms such as Trichuris muris have been maintained in laboratory animals, providing insights into host-parasite interactions and host immune responses. The most used T. muris isolate is the E isolate, established in the laboratory in 1954. However, one concern with these model systems is the potential for laboratory-induced selection and therefore changes in host-parasite interactions. To address these concerns, we compare the E isolate with a recently isolated T. muris isolate (M isolate), established from wild house mice (Mus musculus domesticus, Isle of May, UK), in their capacity to infect laboratory mice. High dose infection of C57BL/6 mice revealed that significantly more parasites of the M isolate survived to the adult stage compared to the E isolate. Worm persistence was associated with heightened TNF-α and IL-10 secretion upon parasite-specific re-stimulation, and higher serum IgG1 and IgG2c levels, concomitant with an increase in T-bet+ and ICOS+ CD4+ T effector-memory cells. Differences in host response to the isolates were not as pronounced during low dose infection. Our study highlights the need for regular evaluation of lab-maintained parasite isolates against freshly isolated parasites to understand whether the established lab strains remain relevant model systems for our understanding of parasitic infections.

Specific antibody responses to Qβ-displayed Plasmodium falciparum-derived UB05 and MSP3 proteins in mother-neonate couples.

Malaria blood-stage parasite is a critical pathogenic stage responsible for serious adverse outcomes in pregnant women and their neonates. Immunoglobulin G (IgG) antibody responses specific to various asexual blood-stage antigens were well reported in non-pregnant individuals. However, little is still known during placental malaria. To assess the antibody responses specific to Plasmodium falciparum-derived MSP3 and UB05 malaria vaccine candidates in mother-neonate couples, mother's peripheral blood and neonate's cord blood samples were collected at delivery. After malaria diagnostic, plasma levels of IgG and IgG subclass responses specific to UB05, MSP3 and UB05-MSP3 were determined using ELISA. As outcomes, both mothers and neonates had significantly higher IgG responses to UB05 and UB05-MSP3 compared to anti-MSP3 IgG (p < 0.05), irrespective of malaria status. Significant negative correlations were observed between IgG levels specific to the three antigens and parasitaemia (p < 0.01). Anti-UB05 and anti-UB05-MSP3 IgG levels in neonates showed a significant positive correlation with the corresponding mothers' antibodies (rs = 0.25 with p = 0.04; rs = 0.31 with p = 0.01, respectively). UB05MSP3-specific IgG3 and IgG1 subclass responses were significantly higher than the IgG4 subclass (p < 0.01). The neonates IgG1 and IgG3 levels positively correlated with the corresponding antibody subclasses of mothers. These findings suggest an association between UB05 and UB05-MSP3-specific antibody responses and malaria control during pregnancy. Maternal-foetal transfer of MSP3 and UB05-specific IgG occurs during pregnancy, suggesting the interest in the future malaria vaccination strategies in pregnant women to generate early protective immunity in baby against malaria.

Improvement of RBD-FC Immunogenicity by Using Alum-Sodium Alginate Adjuvant Against SARS-COV-2.

Adjuvants use several mechanisms to boost immunogenicity and to modulate immune response. The strength of adsorption of antigen by adjuvants can be a determinant factor for significant improvement of immunopotentiation. We expressed recombinant RBD-FC in PichiaPink Strain 4 and examined the vaccination of mice by vaccine formulation with different adjuvants (sodium alginate and aluminum hydroxide, alone and together). Sodium alginate significantly increased the immunogenicity and stability of RBD-FC antigen, so RBD-FC formulated with combined alginate and alum (AlSa) and sodium alginate alone showed higher antibody titer and stability. Immunogenicity of RBD-FC:AlSa was determined by serological assays including direct enzyme-linked immunosorbent assay (ELISA) and surrogate virus neutralization test (sVNT). High levels of IgGs and neutralizing antibodies were measured in serum of mice immunized with the RBD-FC:AlSa formulation. On the other hand, cytokines IL-10 and INF-γ were severely accumulated in response to RBD-FC:AlSa, and after 10 days, their accumulation was significantly declined, whereas IL-4 showed the highest and the lowest accumulation in response to alum and alginate, respectively. Our data may suggest that combination of alum and sodium alginate has a better compatibility with RBD-FC in vaccine formulation.

Severe chronic spontaneous urticaria responding and not responding to omalizumab: analysis of the prognostic value of known and novel in-vitro variables.

Background. Chronic spontaneous urticaria (CSU) response to anti-IgE treatment can be rapid, late or absent. Recently, potential mechanisms of activation of mast cells alternative to FceRI, including mas-related G protein-coupled receptor X2 (MRGPRX2), activation of coagulation cascade, and activation of eosinophils have been described. We measured several potential in-vitro markers, including well-known MRGPRX2 activators, in sera of patients CSU both responding and not responding to omalizumab. Methods. D-dimer, substance P (SP), eosinophil cationic protein (ECP), soluble MRGPRX2, IgE anti-FceRI, IgE anti-FceRII, IgG anti-FceRI and IgG anti-FceRII were measured in 32 patients with severe CSU at baseline and one week after the start of omalizumab therapy, and in 20 healthy controls. Results. At baseline CSU patients showed significantly higher levels of D-dimer, IgE anti-FceRI, IgG anti-FceRI, and ECP (p < 0.001 in all cases), and significantly lower levels of soluble MRGPRX2 (p = 0.009) than controls. The two groups showed similar levels of IgG and IgE to FceRII and SP. One week after the first omalizumab administration there was a significant drop of IgE anti-FceRI (p < 0.001) and D-dimer (p = 0.028), in early responders. SP increased in all CSU patients (p < 0.001) irrespective of the final response to omalizumab. IgE anti-FceRI response at one week was associated with the final response to omalizumab (OR:0.12 [95%CI 0.01-1.06]). Conclusions. Severe CSU is associated with high plasma levels of several biomarkers including D-dimer, IgE anti-FceRI, IgG anti-FceRI and ECP and low levels of soluble MRGPRX2. IgE anti-FceRI response at one week may predict the final response to omalizumab.

Serological Markers of Clinical Improvement in MuSK Myasthenia Gravis.

In this retrospective longitudinal study, we aimed at exploring the role of (a) MuSK-immunoglobulin G (IgG) levels, (b) predominant MuSK-IgG subclasses, and (c) antibody affinity as candidate biomarkers of severity and outcomes in MuSK-MG, using and comparing different antibody testing techniques. Total MuSK-IgGs were quantified with radioimmunoassay (RIA), ELISA, flow cytometry, and cell-based assay (CBA) serial dilutions using HEK293 cells transfected with MuSK-eGFP. MuSK-IgG subclasses were measured by flow cytometry. SAffCon assay was used for determining MuSK-IgG affinity. Forty-three serum samples were obtained at different time points from 20 patients with MuSK-MG (median age at onset: 48 years, interquartile range = 27.5-72.5; women, 16/20), with 9 of 20 (45%) treated with rituximab. A strong correlation between MuSK-IgG levels measured by flow cytometry and RIA titers was found (rs = 0.74, 95% CI 0.41-0.89, p = 0.0003), as well as a moderate correlation between CBA end-point titers and RIA titers (rs = 0.47, 95% CI 0.01-0.77, p = 0.0414). A significant correlation was found between MuSK-IgG flow cytometry levels and disease severity (rs = 0.39, 95% CI 0.06-0.64, p = 0.0175; mixed-effects model estimate: 2.296e-06, std. error: 1.024e-06, t = 2.243, p = 0.032). In individual patients, clinical improvement was associated with decrease in MuSK-IgG levels, as measured by either flow cytometry or CBA end-point titration. In all samples, MuSK-IgG4 was the most frequent isotype (mean ± SD: 90.95% ± 13.89). A significant reduction of MuSK-IgG4 and, to a lesser extent, of MuSK-IgG2, was seen in patients with favorable clinical outcomes. A similar trend was confirmed in the subgroup of rituximab-treated patients. In a single patient, MuSK-IgG affinity increased during symptom exacerbation (KD values: 62 nM vs 0.6 nM) while total MuSK-IgG and IgG4 levels remained stable, suggesting that affinity maturation may be a driver of clinical worsening. Our data support the quantification of MuSK antibodies by flow cytometry. Through a multimodal investigational approach, we showed that total MuSK-IgG levels, MuSK-IgG4 and MuSK-IgG2 levels, and MuSK-IgG affinity may represent promising biomarkers of disease outcomes in MuSK-MG.

Altered serum metabolome is associated with disease activity and immune responses in rheumatoid arthritis.

Rheumatoid arthritis (RA) is widespread globally, with the emergence of metabolites derived from both the host and microbes playing a pivotal role in its pathogenesis. This study aims to elucidate the relationships between serum metabolites and the immunological and clinical features of RA. Serum samples were collected from 35 RA patients and 37 healthy controls (HC). Metabolite profiling was performed using gas chromatography-mass spectrometry (GC/MS). Principal component analysis revealed a significant distinction between the RA and HC cohorts. Employing univariate statistical analysis, we identified 36 differential metabolites. Among these, 9 metabolites, including galactose and glucose, were found to be enriched, while the remaining metabolites, such as citric acid, fumaric acid, and inosine, were depleted in RA. These diverse metabolites encompassed various metabolic processes, including the biosynthesis of fatty acids, amino acids, and glucose. The enrichment of glucose and galactose in RA exhibited a substantial correlation with elevated IgG levels, as determined through correlation analysis. Conversely, the depletion of citric acid was correlated with elevated levels of C3 and CRP. Methionine, which also declined in RA patients, displayed a negative correlation with ESR. Furthermore, galactose and glucose exhibited significant positive correlations with naïve B cells, while the decreased eicosanoic acid level in RA was significantly associated with an increase in natural killer cells. Our findings suggest that the altered serum metabolite profile in RA is closely linked to disease severity and the dysregulated immune responses observed in RA patients. Key Points • Identified nine metabolites with upregulated expression and twenty-seven metabolites with downregulated expression. • Established a correlation between alterations in serum metabolite levels and inflammatory markers in RA patients. • Discovered a significant association between changes in serum metabolites and immune cell profiles in RA patients.