Serum IgG Antibodies Research Articles

Cationic-nanogel nasal vaccine containing the ectodomain of RSV-small hydrophobic protein induces protective immunity in rodents.

Respiratory syncytial virus (RSV) is a leading cause of upper and lower respiratory tract infection, especially in children and the elderly. Various vaccines containing the major transmembrane surface proteins of RSV (proteins F and G) have been tested; however, they have either afforded inadequate protection or are associated with the risk of vaccine-enhanced disease (VED). Recently, F protein-based maternal immunization and vaccines for elderly patients have shown promising results in phase III clinical trials, however, these vaccines have been administered by injection. Here, we examined the potential of using the ectodomain of small hydrophobic protein (SHe), also an RSV transmembrane surface protein, as a nasal vaccine antigen. A vaccine was formulated using our previously developed cationic cholesteryl-group-bearing pullulan nanogel as the delivery system, and SHe was linked in triplicate to pneumococcal surface protein A as a carrier protein. Nasal immunization of mice and cotton rats induced both SHe-specific serum IgG and mucosal IgA antibodies, preventing viral invasion in both the upper and lower respiratory tracts without inducing VED. Moreover, nasal immunization induced greater protective immunity against RSV in the upper respiratory tract than did systemic immunization, suggesting a critical role for mucosal RSV-specific IgA responses in viral elimination at the airway epithelium. Thus, our nasal vaccine induced effective protection against RSV infection in the airway mucosa and is therefore a promising vaccine candidate for further development.

Inhibition of complement C3 signaling ameliorates locomotor and visual dysfunction in autoimmune inflammatory diseases

Neuromyelitis optica (NMO) is an autoimmune inflammatory disease of the central nervous system (CNS) characterized by transverse myelitis and optic neuritis. The pathogenic serum IgG antibody against the aquaporin-4 (AQP4) on astrocytes triggers the activation of the complement cascade, causing astrocyte injury, followed by oligodendrocyte injury, demyelination, and neuronal loss. Complement C3 is positioned as a central player that relays upstream initiation signals to activate downstream effectors, potentially stimulating and amplifying host immune and inflammatory responses. However, whether targeting the inhibition of C3 signaling could ameliorate tissue injury, locomotor defects, and visual impairments in NMO remains to be investigated. In this study, using the targeted C3 inhibitor CR2-Crry led to a significant decrease in complement deposition and demyelination in both slice cultures and focal intracerebral injection models. Moreover, the treatment downregulated the expression of inflammatory cytokines and improved motor dysfunction in a systemic NMO mouse model. Similarly, employing serotype 2/9 adeno-associated virus (AAV2/9) to induce permanent expression of CR2-Crry resulted in a reduction in visual dysfunction by attenuating NMO-like lesions. Our findings reveal the therapeutic value of inhibiting the complement C3 signaling pathway in NMO.

Detection of serum Aspergillus-specific IgM and IgG antibody levels for the diagnosis of chronic pulmonary aspergillosis developed in patients with tuberculosis.

Chronic pulmonary aspergillosis (CPA) is common among individuals with underlying lung diseases. The clinical manifestations of CPA include systemic symptoms (e.g., weight loss, fatigue, fever), chronic productive cough, chest discomfort, and occasional haemoptysis, which are similar to the manifestations of pulmonary tuberculosis (PTB) and are often misdiagnosed as PTB. Considering the striking similarities between CPA and PTB in clinical manifestations and imaging features, more specific microbiological and serological detections are needed for a definitive diagnosis. This study aimed to explore the clinical characteristics of CPA in TB as well as the diagnostic significance of Aspergillus-specific IgG and Aspergillus-specific IgM.A total of 140 patients diagnosed with TB by culture between December 2017 and February 2019 were included. Enrolled patients were categorized into two groups (CPA group and non-CPA group) according to CPA diagnostic criteria. All collected specimens were subjected to Aspergillus-specific IgG and IgM detection testing.The median concentration of Aspergillus-specific IgG in the CPA group (211.04 AU/ml) was significantly higher than that in the non-CPA group (77.88 AU/ml) (Z value - 6.397, P < 0.001). The sensitivity and specificity of Aspergillus-specific IgG for CPA diagnosis were 81.82% and 72.97%, respectively. In the chronic cavitary pulmonary aspergillosis (CCPA) group, the IgG positivity rate (≥ 120 AU/ml) was 96.2%, which was 21.4% in the non-CCPA patients (P < 0.001).The detection of Aspergillus-specific IgG serological changes is feasible and facilitates reliable differentiation between Aspergillus and Mycobacterium tuberculosis infection. However, Aspergillus-specific IgM has limited diagnostic value, with unsatisfactory sensitivity results.

CHO-produced RBD-Fc subunit vaccines with alternative adjuvants generate immune responses against SARS-CoV-2.

Subunit vaccines feature critical advantages over other vaccine platforms such as stability, price, and minimal adverse effects. To maximize immunological protection of subunit vaccines, adjuvants are considered as main components that are formulated within the subunit vaccine. They can modulate adverse effects and enhance immune outcomes. However, the most suitable formulation providing the best immunological outcomes and safety are still under investigation. In this report, we combined recombinant RBD with human IgG1 Fc to create an RBD dimer. This fusion protein was expressed in CHO and formulated with alternative adjuvants with different immune activation including Montanide ISA51, Poly (I:C), and MPLA/Quil-A® as potential vaccine candidate formulations. Using the murine model, a potent induction of anti-RBD IgG antibodies in immunized mice sera were observed. IgG subclass analyses (IgG1/IgG2a) illustrated that all adjuvanted formulations could stimulate both Th1 and Th2-type immune responses in particular Poly (I:C) and MPLA/Quil-A®, eliciting greater balance. In addition, Montanide ISA51-formulated RBD-Fc vaccination provided a promising level of neutralizing antibodies against live wild-type SARS-CoV-2 in vitro followed by Poly (I:C) and MPLA/Quil-A®, respectively. Also, mice sera from adjuvanted formulations could strongly inhibit RBD:ACE2 interaction. This study offers immunogenicity profiles, forecasted safety based on Vaccine-associated enhanced disease (VAED) caused by Th1-skewed immunity, and neutralizing antibody analysis of candidates of RBD-Fc-based subunit vaccine formulations to obtain an alternative subunit vaccine formulation against SARS-CoV-2.

Development of Chimeric Hepatitis B (HBV) – Norovirus (NoV) P particle as candidate vaccine against Hepatitis B and norovirus infection

IntroductionHepatitis B remains a global problem with no effective treatment. Here, a mucosal vaccine candidate was developed with HBsAg and HBcAg, to provide both prophylactic and therapeutic protection against hepatitis B. The antigens were presented using the P particle of human norovirus (HuNov). As a result, the chimeric HBV – HuNoV P particle can act as a dual vaccine for hepatitis B and HuNoV. MethodsThe vaccine candidate was expressed and purified from Escherichia coli BL21 (DE3) cells. HBV-HuNoV chimeric P particles were successfully expressed and isolated, with sizes of approximately 25.64 nm. Then, the HBV-HuNoV chimeric P particles were evaluated for safety and immunogenicity in mice and gnotobiotic (Gn) pigs. After three doses (5 µg/dose in mice and 200 µg/dose in Gn pigs) of intranasal immunization, humoral and cellular immune responses, as well as toxicity, were evaluated. ResultsThe vaccine candidate induced strong HBV-HuNoV specific IFN-γ producing T-cell responses in the ileum, spleen, and blood of Gn pigs. Serum IgG and IgA antibodies against HBV-HuNoV chimeric P particles also increased significantly in Gn pigs. Increased HBsAg- and HuNoV-specific serum IgG responses were observed in mice and Gn pigs, although not statistically significant. The vaccine candidate did not show any toxicity in mice. ConclusionsIn summary, the chimeric HBV-HuNoV P particle vaccine given intranasally was safe and induced strong cellular and humoral immune responses in Gn pig. Modifications to the vaccine structure and dosage need to be evaluated in future studies to further enhance immunogenicity and induce more balanced humoral and cellular responses.

Unveiling a New Perspective on Distinguishing Omicron Breakthrough Cases and Postimmune COVID-19-Naive Individuals: Insights from Antibody Profiles.

In the situation of mass vaccination against COVID-19, few studies have reported on the early kinetics of specific antibodies (IgG/IgM/IgA) of vaccine breakthrough cases. There is still a lack of epidemiological evidence about the value of serological indicators in the auxiliary diagnosis of COVID-19 infection, especially when the nucleic acid results were undetectable. Omicron breakthrough cases post-inactivated vaccination (n = 456) and COVID-19-naive individuals with two doses of inactivated vaccination (n = 693) were enrolled. Blood samples were collected and tested for SARS-CoV-2 antibody levels based on the magnetic chemiluminescence enzyme immunoassay. Among Omicron breakthrough cases, the serum IgG antibody level was 36.34 Sample/CutOff (S/CO) (95% confidence interval [CI], 31.89 to 40.79) in the acute phase and 88.45 S/CO (95% CI, 82.79 to 94.12) in the recovery phase. Serum IgA can be detected in the first week post-symptom onset (PSO) and showed an almost linear increase within 5 weeks PSO. Compared with those of breakthrough cases, IgG and IgA titers of the postimmune group were much lower (4.70 S/CO and 0.46 S/CO, respectively). Multivariate regression showed that serum IgG and IgA levels in Omicron breakthrough cases were mainly affected by the weeks PSO (P < 0.001). Receiver operating characteristic ROC0 curve analysis showed that the area under the curve (AUC) was 0.744 and 0.806 when the cutoff values of IgA and IgG were 1 S/CO and 15 S/CO, respectively. Omicron breakthrough infection can lead to a further increase in IgG and IgA levels relative to those of the immunized population. When nucleic acid real-time PCR was negative, we would use the kinetics of IgG and IgA levels to distinguish the breakthrough cases from the immunized population. IMPORTANCE This study fills a gap in the epidemiological evidence by investigating the value of serological indicators, particularly IgG and IgA levels, in the auxiliary diagnosis of COVID-19 infections when nucleic acid results are undetectable. The findings reveal that among Omicron breakthrough cases, both IgG and IgA antibody levels exhibit significant changes. Serum IgG levels increase during the acute phase and rise further in the recovery phase. Serum IgA can be detected as early as the first week post-symptom onset (PSO), showing a consistent linear increase within 5 weeks PSO. Furthermore, receiver operating characteristic (ROC) curve analysis demonstrates the potential of IgG and IgA cutoff values as diagnostic markers. The study's conclusion underscores the importance of monitoring IgG and IgA kinetics in distinguishing Omicron breakthrough cases from vaccinated individuals. These findings contribute to the development of more accurate diagnostic approaches and help inform public health strategies during the ongoing COVID-19 pandemic.

Frequency of dyspeptic symptoms, anxiety, depression and health-related quality of life among patients with chronic gastritis according to Helicobacter pylori CagA and VacA status: a cross-sectional study

Objective — to determine the frequency of dyspeptic symptoms, anxiety and depression and to describe health‑related quality of life in patients with chronic gastritis according to Helicobacter pylori cytotoxin‑associated gene A and vacuolating cytotoxin A status.&#x0D; Materials and methods. This cross‑sectional study included a total of 84 patients with H. pylori‑associated chronic gastritis (CG). Based on H. pylori virulence factors status patients were categorized into 2 groups: 50 patients with the cytotoxin‑associated gene A (CagA) and vacuolating cytotoxin A (VacA)‑positive H. pylori strains (Group 1) and 34 patients with CagA‑ and VacA‑negative H. pylori strains (Group 2). The H. pylori virulence factors were determined by the polymerase chain reaction using paraffin stomach biopsies. Serum IgA and IgG antibodies to CagA and VacA were evaluated by solid‑phase enzyme‑linked immunoabsorbent assay. The Hospital Anxiety and Depression Scale (HADS) was used to identify anxiety disorders and depression. The MOS 36‑Item Short Form Health Survey (SF‑36) questionnaire was used to assess the health‑related quality of life (HRQoL). Statistical analysis was performed using Stata 11 and Statistica 6 software packages.&#x0D; Results. Patients with CagA‑ and VacA‑positive H. pylori strains were more likely to have epigastric pain than patients with CagA‑ and VacA‑negative H. pylori strains (60% vs. 35.3%, p=0.026). No statistical difference was observed between the frequency of epigastric burning, early satiety, and postprandial fullness in both groups (р &gt;0.05). Anxiety and depression were significantly more prevalent in patients with CagA‑ and VacA‑positive H. pylori strains (p=0.041; р=0.032, respectively). Patients of Group 1 had significantly lower HRQoL in the domains of Role‑Physical (50 vs. 75; p=0.0001), Bodily Pain (57.5 vs. 77.5; p=0.0001), General Health (45 vs. 75; p=0.0001), Vitality (55 vs. 80; p=0.0011) and Mental Health (56 vs. 84; p=0.0001).&#x0D; Conclusions. H. pylori CagA and VacA‑positive status is an important factor that may have an impact on the clinical course of H. pylori‑associated gastritis. Higher frequency of epigastric pain, anxiety, and depression, as well as lower health‑related quality of life were observed in patients with CagA‑ and VacA‑positive H. pylori strains.&#x0D;

Immunogenicity, safety and clinical outcomes of the SARS-CoV-2 BNT162b2 vaccine in adolescents with type 1 diabetes.

The mRNA-based BNT162b2 (Pfizer-BioNTech) vaccine has been shown to elicit robust systemic immune response and confer substantial protection against the severe coronavirus disease (COVID-19), with a favorable safety profile in adolescents. However, no data exist regarding immunogenicity, reactogenicity and clinical outcomes of COVID-19 vaccines in adolescents with type 1 diabetes (T1D). In this prospective observational cohort study, we examined the humoral immune responses and side effects induced by the BNT162b2 vaccine, as well as, the rate and symptomatology of laboratory-confirmed COVID-19 vaccine breakthrough infections after completion of dual-dose BNT162b2 vaccination in adolescents with T1D and compared their data with those of healthy control adolescents. The new data obtained after the vaccination of adolescents with T1D could guide their further COVID-19 vaccination schedule. A total of 132 adolescents with T1D and 71 controls were enrolled in the study, of whom 81 COVID-19 infection-naive adolescents with T1D (patient group) and 40 COVID-19 infection-naive controls (control group) were eligible for the final analysis. The response of participants to the BNT162b2 vaccine was assessed by measuring their serum IgG antibodies to the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), 4-6 weeks after the receipt of first and second vaccine doses. Data about the adverse events of the vaccine was collected after the receipt of each vaccine dose. The rate of COVID-19 vaccine breakthrough infections was evaluated in the 6-month period following second vaccination. After vaccinations, adolescents with T1D and controls exhibited similar, highly robust increments in anti-SARS-CoV-2 IgG titers. All the participants in the patient and control groups developed anti-SARS-CoV-2 IgG titers over 1,050 AU/ml after the second vaccine dose which is associated with a neutralizing effect. None of the participants experienced severe adverse events. The rate of breakthrough infections in the patient group was similar to that in the control group. Clinical symptomatology was mild in all cases. Our findings suggest that two-dose BNT162b2 vaccine administered to adolescents with T1D elicits robust humoral immune response, with a favorable safety profile and can provide protection against severe SARS-CoV-2 infection similar to that in healthy adolescents.

Longitudinal gut microbiome analyses and blooms of pathogenic strains during lupus disease flares

ObjectiveWhereas genetic susceptibility for systemic lupus erythematosus (SLE) has been well explored, the triggers for clinical disease flares remain elusive. To investigate relationships between microbiota community resilience and disease activity,...

Gonococcal microparticle vaccine in dissolving microneedles induced immunity and enhanced bacterial clearance in infected mice

There is an alarming rise in the number of gonorrhea cases worldwide. Neisseria gonorrhoeae, the bacteria that causes gonorrhea infection, has gradually developed antimicrobial resistance over the years. To date, there is no licensed vaccine for gonorrhea. This study investigates the in vivo immunogenicity of a whole-cell inactivated gonococci in a microparticle formulation (Gc-MP) along with adjuvant microparticles (Alhydrogel®- Alum MP and AddaVax™ MP) delivered transdermally using dissolving microneedles (MN). The proposed vaccine formulation (Gc-MP + Alum MP + AddaVax™ MP) was assessed for induction of humoral, cellular, and protective immune responses in vivo. Our results show the induction of significant gonococcal-specific serum IgG, IgG1, IgG2a, and vaginal mucosal IgA antibodies in mice immunized with Gc-MP + Alum MP + AddaVax™ MP and Gc-MP when compared to the control groups receiving blank MN or no treatment. The serum bactericidal assay revealed that the antibodies generated in mice after immunization with Gc-MP + Alum MP + AddaVax™ MP were bactericidal towards live Neisseria gonorrhoeae. Gc-MP + Alum MP + AddaVax™ MP and Gc-MP-immunized mice showed enhanced clearance rate of gonococcal bacterial infection post challenge. In contrast, the control groups did not begin to clear the infection until day 10. In addition, the mice which received Gc-MP + Alum MP + AddaVax™ MP showed enhanced expression of cellular immunity markers CD4 and CD8 on the surface of T cells in the spleen and lymph nodes. Taken together, the data shows that microneedle immunization with whole-cell inactivated gonococci MP in mice induced humoral, cellular, and protective immunity against gonococcal infection.

Mycobacterium avium subsp. paratuberculosis Antigens Elicit a Strong IgG4 Response in Patients with Multiple Sclerosis and Exacerbate Experimental Autoimmune Encephalomyelitis.

Neuroinflammation can be triggered by microbial products disrupting immune regulation. In this study, we investigated the levels of IgG1, IgG2, IgG3, and IgG4 subclasses against the heat shock protein (HSP)70533-545 peptide and lipopentapeptide (MAP_Lp5) derived from Mycobacterium avium subsp. paratuberculosis (MAP) in the blood samples of Japanese and Italian individuals with relapsing remitting multiple sclerosis (MS). Additionally, we examined the impact of this peptide on MOG-induced experimental autoimmune encephalomyelitis (EAE). A total of 130 Japanese and 130 Italian subjects were retrospectively analyzed using the indirect ELISA method. Furthermore, a group of C57BL/6J mice received immunization with the MAP_HSP70533-545 peptide two weeks prior to the active induction of MOG35-55 EAE. The results revealed a significantly robust antibody response against MAP_HSP70533-545 in serum of both Japanese and Italian MS patients compared to their respective control groups. Moreover, heightened levels of serum IgG4 antibodies specific to MAP antigens were correlated with the severity of the disease. Additionally, EAE mice that were immunized with MAP_HSP70533-545 peptide exhibited more severe disease symptoms and increased reactivity of MOG35-55-specific T-cell compared to untreated mice. These findings provide evidence suggesting a potential link between MAP and the development or exacerbation of MS, particularly in a subgroup of MS patients with elevated serum IgG4 levels.

RDE Treatment Prevents Non-Specific Detection of SARS-CoV-2- and Influenza-Specific IgG Antibodies in Heat-Inactivated Serum Samples.

Assessing the levels of serum IgG antibodies is widely used to measure immunity to influenza and the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after natural infection or vaccination with specific vaccines, as well as to study immune responses to these viruses in animal models. For safety reasons, sometimes serum specimens collected from infected individuals are subjected to heat inactivation at 56 °C to reduce the risk of infecting personnel during serological studies. However, this procedure may affect the level of virus-specific antibodies, making the results of antibody immunoassays uninterpretable. Here, we evaluated the effect of the heat inactivation of human, ferret and hamster serum samples on the binding of IgG antibodies to the influenza and SARS-CoV-2 antigens. For this, serum samples of naive and immune hosts were analyzed in three variants: (i) untreated sera, (ii) heated at 56 °C for 1 h, and (iii) treated with receptor-destroying enzyme (RDE). The samples were studied through an in-house enzyme-linked immunosorbent assay (ELISA) using whole influenza virus or recombinant proteins corresponding to nucleocapsid (N) protein and the receptor-binding domain of SARS-CoV-2 Spike (RBD) as antigens. We demonstrated that the heat inactivation of the naive serum samples of various hosts can lead to false-positive results, while RDE treatment abolished the effect of the non-specific binding of IgG antibodies to the viral antigens. Furthermore, RDE also significantly decreased the level of virus-specific IgG antibodies in SARS-CoV-2 and influenza-immune sera of humans and animals, although it is unknown whether it actually removes true virus-specific IgG antibodies or only non-specifically binding artifacts. Nevertheless, we suggest that the RDE treatment of human and animal sera may be useful in preventing false-positive results in various immunoassays, while also neutralizing infectious virus, since the standard protocol for the use of RDE also includes heating the sample at 56 °C.

#5520 EFFICACY OF MRNA VACCINE BNT162B2 AGAINST NOVEL SARS-COV-2 VIRUS IN END-STAGE KIDNEY DISEASE

Abstract Background and Aims Covid-19 pandemic affected more than 600 million people worldwide. Chronic kidney disease was shown to be a significant risk factor for disease severity. The introduction of the novel mRNA vaccines against SARS-CoV-2 prompted studies to evaluate their efficacy and safety. This study aims to assess the humoral response to the BNT162b2 vaccine, its durability, the booster effect, and breakthrough infections among end-stage renal disease patients (ESRD). Methods A one-year, single center, observational prospective study was conducted between 2021 and 2022. The cohort included adult dialysis patients (n = 143), kidney transplant recipients (11), and healthy controls (n = 75). Demographic and clinical data were retrieved from electronic medical records. All participants received 30 µg/dose of BNT162b2 mRNA vaccine, at 0 and 3 weeks. A third vaccine (booster) was administered at least 6 months after the first dose. SARS-CoV-2 infection was diagnosed based on PCR test of nasal and oropharyngeal swabs. Infections that occurred from January 2022 were attributed to omicron variant. Longitudinal blood samples were collected as indicated in Figure after the first vaccine dose (V1) and after the booster dose (V3). Humoral immune response was assessed by measuring serum IgG antibodies against the receptor-binding domain of the SARS-CoV-2 S1 subunit, using the ABBOTT kit. The study protocol was approved by the Institutional Review Board and was conducted in adherence to the Declaration of Helsinki. Results Twenty-eight weeks after two doses of vaccine, the median antibody levels were significantly lower in dialysis and transplant patients compared with healthy controls (122 AU/mL (2–4,557) and 6 AU/mL (1–217) vs 831 AU/mL (117–40,000), respectively). Furthermore, only 75% of dialysis patients developed positive antibody response (&amp;gt;50 AU/mL) as compared to 100% in controls (see Figure 1). A significant waning of immunity was seen over time in both dialysis and healthy participants (p &amp;lt; .0001). Four weeks after a booster dose, antibody levels surged and did not differ between dialysis and healthy participants 13,840 ± 15,126 AU/mL vs 18,080 ± 13,354 AU/mL, respectively (p = .283). Non-responder rate among dialysis patients dropped from 21% after a 2-dose vaccination to 7% after a booster dose. Lower antibody levels measured at 28-week after the first vaccination were associated with higher risk for Covid-19 infection (p = .021). Of note, all infection cases occurred in subjects with antibody levels below 1050 AU/mL. However, no association was found between antibody levels and Covid-19-omicron variant infection rate among dialysis patients and healthy controls (p = 0.650). Conclusions Dialysis patients had a blunted humoral immune response after two doses of BNT162b2 vaccine compared with healthy controls, which improved after a booster dose. Based on the observed omicron variant breakthrough infections, further studies are needed to improve the vaccines' efficacy against the evolving SARS-CoV-2 variants.

Plant-Produced Nanoparticles Based on Artificial Self-Assembling Peptide Bearing the Influenza M2e Epitope.

Despite advances in vaccine development, influenza remains a persistent global health threat and the search for a broad-spectrum recombinant vaccine against influenza continues. The extracellular domain of the transmembrane protein M2 (M2e) of the influenza A virus is highly conserved and can be used to develop a universal vaccine. M2e is a poor immunogen by itself, but it becomes highly immunogenic when linked to an appropriate carrier. Here, we report the transient expression of a recombinant protein comprising four tandem copies of M2e fused to an artificial self-assembling peptide (SAP) in plants. The hybrid protein was efficiently expressed in Nicotiana benthamiana using the self-replicating potato virus X-based vector pEff. The protein was purified using metal affinity chromatography under denaturing conditions. The hybrid protein was capable of self-assembly in vitro into spherical particles 15-30 nm in size. The subcutaneous immunization of mice with M2e-carrying nanoparticles induced high levels of M2e-specific IgG antibodies in serum and mucosal secretions. Immunization provided mice with protection against a lethal influenza A virus challenge. SAP-based nanoparticles displaying M2e peptides can be further used to develop a recombinant "universal" vaccine against influenza A produced in plants.

Intranasal Single-Replication Influenza Vector Induces Cross-Reactive Serum and Mucosal Antibodies against SARS-CoV-2 Variants.

Current SARS-CoV-2 vaccines provide protection for COVID-19-associated hospitalization and death, but remain inefficient at inhibiting initial infection and transmission. Despite updated booster formulations, breakthrough infections and reinfections from emerging SARS-CoV-2 variants are common. Intranasal vaccination to elicit mucosal immunity at the site of infection can improve the performance of respiratory virus vaccines. We developed SARS-CoV-2 M2SR, a dual SARS-CoV-2 and influenza vaccine candidate, employing our live intranasal M2-deficient single replication (M2SR) influenza vector expressing the receptor binding domain (RBD) of the SARS-CoV-2 Spike protein of the prototype strain, first reported in January 2020. The intranasal vaccination of mice with this dual vaccine elicits both high serum IgG and mucosal IgA titers to RBD. Sera from inoculated mice show that vaccinated mice develop neutralizing SARS-CoV-2 antibody titers against the prototype and Delta virus strains, which are considered to be sufficient to protect against viral infection. Moreover, SARS-CoV-2 M2SR elicited cross-reactive serum and mucosal antibodies to the Omicron BA.4/BA.5 variant. The SARS-CoV-2 M2SR vaccine also maintained strong immune responses to influenza A with high titers of anti H3 serum IgG and hemagglutination inhibition (HAI) antibody titers corresponding to those seen from the control M2SR vector alone. With a proven safety record and robust immunological profile in humans that includes mucosal immunity, the M2SR influenza viral vector expressing key SARS-CoV-2 antigens could provide more efficient protection against influenza and SARS-CoV-2 variants.

The Case Files

The Case Files

Hemophore-like proteins produced by periodontopathogens are recognized by the host immune system and react differentially with IgG antibodies

ABSTRACT Aims Hemophore-like proteins sequester heme from host hemoproteins. We aimed to determine whether the host immune system can recognize not only Porphyromonas gingivalis HmuY but also its homologs expressed by other periodontopathogens, and how periodontitis influences the production of respective antibodies. Methods The reactivity of total bacterial antigens and purified proteins with serum IgG antibodies of 18 individuals with periodontitis and 17 individuals without periodontitis was examined by enzyme-linked immunosorbent assay (ELISA). To compare IgG reactivity between groups with and without periodontitis and within the various dilutions of sera, statistical analysis was performed using the Mann-Whitney U-test and two-way ANOVA test with the post-hoc Bonferroni test. Results Individuals with periodontitis produced IgG antibodies reacting more strongly not only with total P. gingivalis antigens (P = 0.0002; 1:400) and P. gingivalis HmuY (P = 0.0016; 1:100) but also with Prevotella intermedia PinA (P = 0.0059; 1:100), and with low efficiency with P. intermedia PinO (P = 0.0021; 1:100). No increase in the reactivity of IgG antibodies with Tannerella forsythia Tfo and P. gingivalis HusA was found in individuals with periodontitis. Conclusions Although hemophore-like proteins are structurally related, they are differentially recognized by the host immune system. Our findings point to specific antigens, mainly P. gingivalis HmuY and P. intermedia PinA, whose immunoreactivity could be further investigated to develop markers of periodontitis.

Age, Sex and BMI Relations with Anti-SARS-CoV-2-Spike IgG Antibodies after BNT162b2 COVID-19 Vaccine in Health Care Workers in Northern Greece

The aim of this work was to study age, sex, and BMI (Body Mass Index)-related differences in the development of anti-SARS-CoV-2-Spike IgG antibodies, after vaccination with the BNT162b2 COVID-19 vaccine, in health care workers of a General Hospital in a city in Northern Greece. Blood sampling was drawn two to four weeks following the second dose of the vaccine, and six months after the first blood sample collection. Measurement of serum IgG antibodies against the spike domain of SARS-CoV-2 was performed using the SARS-CoV-2 IgG II Quant assay. All participants had sufficient serum IgG titers in the first measurement. Women developed higher IgG titers than men. The IgG titers were inversely related to age in both sexes; there was also a small, insignificant tendency to be inversely related to BMI. Six months after the first measurement, the IgG titers decreased dramatically to values less than 5% of the initial. This decrease was observed in both men and women and was inversely related to age. Multivariate regression analysis showed that age and sex explained with statistical significance 9% of the variance in SARS-CoV-2 IgG titers in our study population; the role of BMI was limited and insignificant.

Anti-ganglioside antibody positive neuromyelitis optica spectrum disorders with peripheral neuropathy: a case report

BackgroundNeuromyelitis optica spectrum disorders (NMOSD) is a group of autoimmune-mediated disorders of the central nervous system primarily involving the optic nerve and spinal cord. There are limited reports of NMOSD associated with peripheral nerve damage.Case presentationWe report a 57-year-old female patient who met the diagnostic criteria for aquaporin 4 (AQP4)-IgG positive NMOSD with undifferentiated connective tissue disease and multiple peripheral neuropathy. In addition, the patient was positive for multiple anti-ganglioside antibodies (anti-GD1a IgG antibodies and anti-GD3 IgM antibodies) and anti-sulfatide IgG antibodies in serum and cerebrospinal fluid. After treatment with methylprednisolone, gamma globulin, plasma exchange, and rituximab, the patient’s status improved and was subsequently discharged from our hospital.ConclusionsThe neurologist should be aware of the unusual association between NMOSD and immune-mediated peripheral neuropathy undifferentiated connective tissue disease and nerve damage mediated by multiple antibodies may have combined to cause peripheral nerve damage in this patient.

A Newly Identified Spike Protein Targeted Linear B-Cell Epitope Based Dissolvable Microneedle Array Successfully Eliciting Neutralizing Activities against SARS-CoV-2 Wild-Type Strain in Mice.

Vaccination is a cost-effective medical intervention. Inactivated whole virusor large protein fragments-based severe acute respiratory syndrome coronavirus (SARS-CoV-2) vaccines have high unnecessary antigenic load to induce allergenicity and/orreactogenicity, which can be avoided by peptide vaccines of short peptide fragments that may induce highly targeted immune response. However, epitope identification and peptide delivery remain the major obstacles in developing peptide vaccines. Here, a multi-source data integrated linear B-cell epitope screening strategy is presented and a linear B-cell epitope enriched hotspot region is identified in Spike protein, from which a monomeric peptide vaccine (Epitope25) is developed and applied to subcutaneously immunize wildtype BALB/c mice. Indirect ELISA assay reveals specific and dose-dependent binding between Epitope25 and serum IgG antibodies from immunized mice. The neutralizing activity of sera from vaccinated mice is validated by pseudo and live SARS-CoV-2 wild-type strain neutralization assays. Then a dissolvable microneedle array (DMNA) is developed to pain-freely deliver Epitope25. Compared with intramuscular injection, DMNA and subcutaneous injection elicit neutralizing activities against SARS-CoV-2 wild-type strain as demonstrated by live SARS-CoV-2 virus neutralization assay. No obvious damages are found in major organs of immunized mice. This study may lay the foundation for developing linear B-cell epitope-based vaccines against SARS-CoV-2.