Antibody Titers Research Articles

Prevalence of culicine salivary antibodies in non-human primates living in national parks in Thailand.

Macaques are widely distributed in Thailand with remarkable adaptation to living close to humans in residential, religious sites, markets and tourist areas. They play an essential role in the persistence of pathogens in the environment. As reservoir hosts, they are exposed to hematophagous vectors that secrete saliva, a cocktail of bioactive molecules including antigenic components stimulating host antibody production. Subsequent to the detection of mosquito-borne pathogens in macaques living in national parks, we aimed to determine the seroprevalence of antibodies to crude salivary gland extracts (SGEs) from culicine mosquitoes (Aedes aegypti [Linnaeus, 1762], Ae. albopictus [Skuse, 1895] and Culex quinquefasciatus [Say, 1823]) and compare individual titres between macaque species/national parks (33, Macaca arctoides [I. Geoffroy Saint-Hilaire, 1831] [Primates: Cercopithecidae] from Kaeng Krachan, 23 M. leonina leonina [Blyth, 1863] [Primates: Cercopithecidae] from Khao Yai and four M. fascicularis [Raffles, 1821] [Primates: Cercopithecidae] from Mu Ko Ranong). The anti-mosquito SGE antibodies found in 60 macaques from three national parks indicate varying levels of host-vector exposure. Macaque antibody titres were high against culicine mosquitoes. However, the significant difference among national parks (or macaque species) was only observed against Cx. quinquefasciatus. Correlation analysis of titres between Aedes SGE and arboviruses revealed a significantly more intense immune response against Ae. albopictus in DENV3-positive M. arctoides. Current findings support the concept of salivary biomarkers using accessible SGE, available from mosquito colonies of interest. However, we observed cross-reactivity between Aedes species because of crude SGE containing species-shared proteins. Nevertheless, a potential risk of pathogen transmission is emphasised between national park visitors and macaques via mosquitoes as bridge vectors. This information contributes to preventive measures against mosquito bites, including those implemented in tourist areas.

Modulation of antigen delivery and lymph node activation in nonhuman primates by saponin adjuvant saponin/monophosphoryl lipid A nanoparticle.

Saponin-based vaccine adjuvants are potent in preclinical animal models and humans, but their mechanisms of action remain poorly understood. Here, using a stabilized HIV envelope trimer immunogen, we carried out studies in nonhuman primates (NHPs) comparing the most common clinical adjuvant aluminum hydroxide (alum) with saponin/monophosphoryl lipid A nanoparticles (SMNP), an immune-stimulating complex-like adjuvant. SMNP elicited substantially stronger humoral immune responses than alum, including 7-fold higher peak antigen-specific germinal center B-cell responses, 18-fold higher autologous neutralizing antibody titers, and higher levels of antigen-specific plasma and memory B cells. Positron emission tomography and computed tomography imaging in live NHPs showed that, unlike alum, SMNP promoted rapid antigen accumulation in both proximal and distal lymph nodes (LNs). SMNP also induced strong type I interferon transcriptional signatures, expansion of innate immune cells, and increased antigen-presenting cell activation in LNs. These findings indicate that SMNP promotes multiple facets of the early immune response relevant for enhanced immunity to vaccination.

Cross-neutralization of Influenza A by SARS-CoV-2 specific neutralizing antibodies and polyclonal plasma: Is pre-exposure to SARS-CoV-2 protective against Influenza A?

According to sparse information from various countries, the seasonal influenza virus circulation has drastically decreased during the COVID-19 pandemic. Here, we show the cross-reactivity of anti-SARS-CoV-2 antibodies against influenza viruses. Plasma samples were collected from 311 SARS-CoV-2 infected individuals. The samples were tested for antibody titers against SARS-CoV-2 by ELISA and seasonal influenza virus strains (influenza A/H1N1, A/H3N2, B/Yamagata, and B/Victoria) using a Hemagglutination Inhibition Assay (HAI). In addition, SARS-CoV-2 antibody-positive but Influenza antibody-negative samples (n = 16) were investigated to determine the SARS-CoV-2 antibody-neutralizing potential against influenza viruses by microneutralization (MN) assay. The SARS-CoV-2 genomes were sequenced using Illumina next-generation sequencing, and an in-silico protein structural analysis was performed to identify epitope and antibody binding similarities between SARS-CoV-2 and influenza viruses. Among 16 samples that didn't contain antibodies against Influenza A strains (H1N1 and H3N2), five showed high (MN titer≥20), and six showed moderate (MN titer≥10) capability to neutralize Influenza A. Subsequent in-silico analysis revealed that most efficient binding (>8 kcal/mol) was found between the antibodies of SARS-CoV-2 delta variant (ΔG) with influenza A/H1N1 HA (Hemagglutinin), A/H3N2 HA, A/H1N1 NA (Neuraminidase), and A/H3N2 NA glycoproteins with −12.4, −9.3, −10.1, and −11.7 kcal/mol, respectively. This investigation revealed that neutralizing antibodies of the delta variant cross-reacted with the Influenza A virus, which might protect against influenza viruses and reduce and shift the seasonal influenza circulation during the COVID-19 pandemic. Our findings warrant further study to explain the probable mechanisms of this cross-reactivity.

Safety and Efficacy of Immunization with a Late-Liver-Stage Attenuated Malaria Parasite

BackgroundCurrently licensed and approved malaria subunit vaccines provide modest, short-lived protection against malaria. Immunization with live-attenuated Plasmodium falciparum malaria parasites is an alternative vaccination strategy that has potential to improve protection.MethodsWe conducted a double-blind, controlled clinical trial to evaluate the safety, side-effect profile, and efficacy of immunization, by means of mosquito bites, with a second-generation genetically attenuated parasite (GA2) — a mei2 single knockout P. falciparum NF54 parasite (sporozoite form) with extended development into the liver stage. After an open-label dose-escalation safety phase in which participants were exposed to the bites of 15 or 50 infected mosquitoes (stage A), healthy adults who had not had malaria were randomly assigned to be exposed to 50 mosquito bites per immunization of GA2, an early-arresting parasite (GA1), or placebo (bites from uninfected mosquitoes) (stage B). After the completion of three immunization sessions with 50 mosquito bites per session, we compared the protective efficacy of GA2 against homologous P. falciparum controlled human malaria infection with that of GA1 and placebo. The primary end points were the number and severity of adverse events (in stages A and B) and blood-stage parasitemia greater than 100 P. falciparum parasites per milliliter after bites from GA2-infected mosquitoes (in stage A) and after controlled human malaria infection (in stage B).ResultsAdverse events were similar across the trial groups. Protective efficacy against subsequent controlled human malaria infection was observed in 8 of 9 participants (89%) in the GA2 group, in 1 of 8 participants (13%) in the GA1 group, and in 0 of 3 participants in the placebo group. A significantly higher frequency of P. falciparum–specific polyfunctional CD4+ and Vδ2+ γδ T cells were observed among participants who received GA2 than among those who received GA1, whereas GA2 and GA1 induced similar antibody titers targeting the P. falciparum circumsporozoite protein.ConclusionsIn this small trial, GA2 was associated with a favorable immune induction profile and protective efficacy, findings that warrant further evaluation. (Funded by the Bontius Foundation; ClinicalTrials.gov number, NCT04577066.)

Preliminary Study on Type I Interferon as a Mucosal Adjuvant for Human Respiratory Syncytial Virus F Protein.

Background: Human respiratory syncytial virus (HRSV) imposes a significant disease burden on infants and the elderly. Intranasal immunization using attenuated live vaccines and certain vector vaccines against HRSV has completed phase II clinical trials with good safety and efficacy.Recombinant protein vaccines for mucosal immunization require potent mucosal adjuvants. Type I interferon (IFN), as a natural mucosal adjuvant, significantly enhances antigen-presenting cell processing and antigen presentation, promoting the production of T and B cells. Methods: This study utilized human α2b interferon (IFN-human) and mouse α2 interferon (IFN-mouse) as nasal mucosal adjuvants in combination with fusion protein (F). Intranasal immunization was performed on BALB/c mice to evaluate the immunogenicity of the formulation in vivo. Results: Compared to the F protein immunization group, mice in the F + IFN-Human and F + IFN-Mouse experimental groups exhibited significantly increased neutralizing antibody titers and augmented secretion of IFN-γ and IL-4 by lymphocytes, and both of them could induce the production of high-titer specific IgA antibodies in mice (p < 0.001).The F + IFN-Human immunization induced the highest IgG and IgG1 antibody titers in mice; however, the F + IFN-Mouse immunization group elicited the highest neutralizing antibody titers (598), lowest viral loads in the lungs (Ct value of 31), and fastest weight recovery in mice. Moreover, mice in the F + IFN-Mouse immunization group displayed the mildest lung pathological damage (Total score of pathological injury was 2). Conclusions: In conclusion, IFN-Mouse, as a mucosal adjuvant for HRSV recombinant protein vaccines, demonstrated superior protective effects in mice compared to IFN-Human adjuvants.

A foldon-free prefusion F trimer vaccine for respiratory syncytial virus to reduce off-target immune responses

Respiratory syncytial virus (RSV) is a major cause of severe respiratory disease in infants and older people. Current RSV subunit vaccines are based on a fusion protein that is stabilized in the prefusion conformation and linked to a heterologous foldon trimerization domain to obtain a prefusion F (preF) trimer. Here we show that current RSV vaccines induce undesirable anti-foldon antibodies in non-human primates, mice and humans. To overcome this, we designed a foldon-free RSV preF trimer by elucidating the structural basis of trimerization-induced preF destabilization through molecular dynamics simulations and by introducing amino acid substitutions that negate hotspots of charge repulsion. The highly stable prefusion conformation was validated using antigenic and cryo-electron microscopy analysis. The preF is immunogenic and protective in naive mouse models and boosts neutralizing antibody titres in RSV-pre-exposed mice and non-human primates, while achieving similar titres to approved RSV vaccines in mice. This stable preF design is a promising option as a foldon-independent candidate for a next-generation RSV vaccine immunogen.

MTBVAC induces superior antibody titers and IgG avidity compared to BCG vaccination in non-human primates

The only currently licensed vaccine against tuberculosis (TB), Bacille Calmette Guérin (BCG), is insufficient to control the epidemic. MTBVAC is a live attenuated strain of Mycobacterium tuberculosis (M.tb) and is one the most advanced TB vaccine candidates in the pipeline. It is more efficacious than BCG in preclinical models including non-human primates (NHPs), and has demonstrated safety and immunogenicity in human populations. To better understand the immune mechanisms underlying the superior efficacy conferred by MTBVAC, we characterized M.tb-specific antibody responses in NHPs vaccinated with either BCG or MTBVAC. MTBVAC vaccination induced higher titers of IgG, IgM and IgA, and higher avidity IgG compared with BCG vaccination. IgG avidity correlated with protection following M.tb challenge in the same animals, validating the association previously reported between this measure and protection in the context of intravenous BCG vaccination, suggesting that IgG avidity may represent a relevant marker or correlate of protection from TB.

Anti-SARS-CoV-2 serology based on ancestral RBD antigens does not correlate with the presence of neutralizing antibodies against Omicron variants.

Anti-SARS-CoV-2 serology was developed in 2020 in response to the COVID-19 pandemic to diagnose SARS-CoV-2 infection and monitor an individual's immunity following natural infection or vaccination. Given the relationship between neutralizing antibody titers and protection against severe infection, many studies have evaluated the correlation between serology tests and neutralization assays in the pre-Omicron era. An important potential clinical use of serology, which explores binding antibodies, is estimating an individual's level of protection against new infection, particularly in immunosuppressed individuals and those at risk of severe COVID. However, in the Omicron era, as new viruses evade the immunity induced by previous infections and vaccination, the correlation between binding antibody levels determined by serological assays developed from ancestral antigens and neutralizing antibody titers against new viruses should be re-examined in order to determine whether these assays should be optimized by adapting antigens to the circulating SARS-CoV-2 strains.

A multimodal digital microfluidic testing platform for antibody-producing cell lines.

In recent years, monoclonal antibodies (mAbs) have become a powerful tool in the treatment of human diseases. Currently, over 100 mAbs have received approval for therapeutic use in the US, with wide-ranging applications from cancer to infectious diseases. The predominant method of producing antibodies for therapeutics involves expression in mammalian cell lines. In the mAb production process, significant optimization is typically done to maximize antibody titres from cells grown in bioreactors. Therefore, systems that can miniaturize and automate cell line testing (e.g., viability and antibody production assays) are valuable in reducing therapeutic mAb development costs. Here we present a novel platform for cell line optimization for mAb production using digital microfluidics. The platform enables testing of cell culture samples in 6-8 μL droplets with semi-automated viability, media pH, and antibody production assays. This system provides a unique bridge between cell growth and productivity metrics, while minimizing culture volume requirements for daily testing. We propose that this technology and its future iterations has the potential to help reduce the time-to-market and development costs of antibody-producing cell lines.

Analysis of free-living seabirds from Brazil as potential hosts of Toxoplasma gondii and serological investigation for antibodies against Leptospira spp.

Dispersal patterns of zoonotic pathogens can be strongly influenced by mobility and contact among hosts. Toxoplasma gondii infection has been documented in many avian species, however, there is little information regarding free-living seabird populations. Leptospira can infect domestic and wild animals, with birds being potential carriers of the bacteria. The continental shelf of the southwestern Atlantic Ocean is a foraging area for seabirds that breed locally, as well as migratory seabirds wintering in the area, which may come into contact with each other in prey aggregation areas and contribute to T. gondii and Leptospira spread. Therefore, this study aimed to investigate the prevalence of two important zoonotic pathogens in free-living seabirds. Blood samples were collected from 322 birds of three local breeders (Phaethon aethereus, Sula leucogaster and S. dactylatra) in the eastern coast of Brazil (Abrolhos Archipelago), and two migratory species using the area during the pre-laying (Pterodroma arminjoniana) and the non-breeding periods (Thalassarche chlororhynchos). Serological agglutination tests for detection of anti-Toxoplasma gondii and anti-Leptospira spp. antibodies were performed. None of the seabirds in this study was seroreactive to Leptospira spp., whereas 34.5% (n = 111) of the animals presented antibodies anti-T. gondii. Antibody titers in seropositive birds ranged from 10 to 640. There were seropositive birds in all sampled localities. This study provides the first records for P. arminjoniana and T. chlororhynchos as seropositive to T. gondii, suggesting their potential role as sentinels for the environmental contamination by T. gondii and also T. gondii infection. These findings indicate the circulation of the parasite in the Brazilian coastal and oceanic regions, probably due to the ingestion of T. gondii oocysts by birds, the epidemiological involvement of migratory birds as hosts of pathogens, as well as the role of the historical introduction of invasive vertebrates on Brazilian islands. Therefore, due to the serological evidence of infection, the dynamics of toxoplasmosis in seabirds, regarding their susceptibility towards the disease and the possible anthropogenic influence need to be better understood for the colonies to be included in the wildlife cycle of T. gondii.

Liver Dysfunction in a Patient with Graves' Disease.

Liver dysfunction can occur in patients presenting with thyrotoxicosis, due to several different aetiologies. A 42-year-old man had mild liver dysfunction on presentation with hyperthyroidism due to Graves' disease (GD): ALT 65 (0-45 IU/L), fT4 41.2 (9-23 pmol/L), fT3 > 30.7 (2.4-6 pmol/L), and TSH < 0.01 (0.3-4.2 mIU/L). His liver dysfunction worsened following the initiation of the antithyroid drug (ATD) carbimazole (CBZ), with ALT reaching a zenith of 263 IU/L at 8 weeks following presentation. Consequently, CBZ was stopped, and he was managed with urgent radioiodine therapy. His liver function tests (LFTs) improved within 1 week of stopping carbimazole (ALT 74 IU/L). Thionamide-induced liver dysfunction is more typically associated with a 'cholestatic' pattern, although he had a 'hepatitic' pattern of liver dysfunction. The risk of liver dysfunction in GD increases with older age and higher titres of thyroid-stimulating hormone receptor antibody (TRAb). This review of the literature seeks to explore the possible causes of liver dysfunction in a patient presenting with hyperthyroidism, including thyrotoxicosis-induced liver dysfunction, ATD-related liver dysfunction, and the exacerbation of underlying unrelated liver disease.

Possibilities and Limitations in Substituting anti-Drug Antibody Titers with Signal-to-Noise Ratios: A Comprehensive Comparison Using Two Clinical Trial Datasets of Adalimumab.

Immunogenicity assessment is vital in clinical trials and is measured through a multi-tiered approach (screening, confirmatory and titer assays). However, recent studies have suggested that titer results could be reported from ADA signal-to-noise ratios (S/N ratios=sample mean signal/negative control mean signal). More data analysis using two clinical trials of adalimumab: SB5-1003 (single-dose, healthy participants) and SB5-4001 (multiple-dose, interchangeability study, patients with plaque psoriasis), therefore, is indispensable whether substituting ADA S/N ratio as an alternative way of reporting titer results has no impact on interpretation on clinical outcome. In this study, we demonstrated that there is a strong correlation between S/N ratios and titers and no impact on overall PK results. Nonetheless, sub-analyses with time or adalimumab level showed a change in the regression between S/N ratios and titers, leading to different titer values from the same S/N ratio. These data demonstrate that S/N ratios may fully replace titers in limited circumstances such as a biosimilar study which goal is to prove equivalence between the originator and candidate product, but need a caution in other cases.

Common Presentation and Clinical Correlates of Celiac Disease in Pediatric Population of Pakistan

Objective: To explore the various clinical presentations in childhood celiac disease patients of Sindh, Pakistan. Study Design: Cross-sectional study Setting and Duration of Study: Pediatric Department, Pir Abdul Qadir Shah Jeelani Institute of Medical Sciences, Gambat, Khaipur Mirs Pakistan, from Sep 2018 to Mar 2020. Methodology: A total of 140 children aged between 1-15 years, with diagnosed cases of celiac disease were enrolled in the study. Patients with inconclusive diagnosis, with multiple comorbidities, age &gt;15 years, or children whose parents did not give consent to take part in the study were excluded from the current study. All children were further categorized according to the sociodemographic and clinical presentation. Results: The mean age of patients at the onset of symptoms was 3.15±1.25 years. Out of 140 patients, 74(52.8%) were male and 66(47.1%) female. Out of 140 patients, 28(20%) patients had positive anti-endomysial antibody titers. About 8 patients had concomitant autoimmune diseases i.e. Type 1 diabetes mellitus, out of these 5 tested positive for anti-endomysial antibody titers. The most common presentation was chronic diarrhea, seen in 13(32%) of patients. Conclusion: The current study revealed that the majority of the diagnosed pediatric patients presented with a typical clinical picture of celiac disease.

2D4, a humanized monoclonal antibody targeting CD132, is a promising treatment for systemic lupus erythematosus

Current therapies for systemic lupus erythematosus that target a particular factor or cell type exhibit limited effectiveness. To address this limitation, our focus was on CD132, a subunit common to six inflammatory factor receptors implicated in SLE. Our study revealed heightened CD132 expression in SLE patients’ lymphocytes, contributing to the production of pro-inflammatory cytokines and immunoglobulins. We developed a novel humanized anti-CD132 monoclonal antibody, named as 2D4. 2D4 efficiently blocked IL-21 and IL-15, with limited effectiveness against IL-2, thereby suppressing T and B cells without disrupting immune tolerance. In the mouse immunization model, 2D4 virtually inhibited T cell-dependent, antigen-specific B-cell response. In lupus murine models, 2D4 mitigated inflammation by suppressing multiple pro-inflammatory cytokines and anti-dsDNA antibody titers, also diminishing proteinuria and glomerulonephritis. Compared to Belimumab, 2D4 exhibited superior efficacy in ameliorating the inflammatory state and preserving renal function. Moreover, 2D4 exhibited the ability to inhibit the production of pro-inflammatory factors and autoantibodies in PBMCs from individuals with SLE, highlighting its therapeutic potential for SLE individuals. Potent, 2D4 has the potential to significantly improve clinical outcomes in SLE and other complex autoimmune disorders.

Assessment of Immunological, Skeletal, and Thyroid Function Abnormalities in Paediatric Morphoea

Abstract Background: Morphoea is a sclerosing disorder of skin and subcutaneous tissue. Paediatric morphoea shows increased prevalence of various auto-immune diseases, bone deformities, and systemic abnormalities. There is paucity of studies on various immunological, skeletal, and thyroid function abnormalities in paediatric morphoea. Aims and Objectives: To describe immunological, skeletal, and thyroid function abnormalities present in paediatric morphoea patients. Materials and Methods: This cross-sectional study was conducted from January 2021 to March 2023 in the Dermatology outpatient department in a tertiary care hospital. All paediatric morphoea patients were included in this study. All were subjected to detailed history, clinical examination, and investigations including complete blood count, serum IgE, anti-nuclear antibody, thyroid function tests, anti-thyroid peroxidase antibodies, and radiological investigations. Results: A total of 42 children were recruited, out of which 61.90% were females and 38.09% were males. The majority were in the age group of 4–8 years. The most common type of morphoea was encoup de sabre. Anaemia was present in 14.28% patients. Serum IgE levels were raised in 33.33% patients. Thyroid stimulating hormone was raised in 11.9% patients. 33.33% had raised anti-thyroid peroxidase levels. Anti-nuclear antibody titres and rheumatoid factor were raised in 7.14% and 4.76% patients, respectively. Magnetic resonance imaging brain revealed abnormalities in three patients as hyper-intensities in subcortical white matter. Conclusion: Morphoea in children can be associated with varied immunological, osteoarticular, and neurological abnormalities. This study highlights the multi-system involvement in morphoea and the need for larger data and well-designed therapeutic trials for generating evidence-based treatment of this potentially disfiguring disease.

Stability of closed and needle-punctured vials of Porvac® subunit vaccine against classical swine fever subjected to thermal stress

BackgroundClassical Swine Fever (CSF) is still one of the most economically important viral diseases of pigs. In endemic countries, the disease is controlled mostly through vaccination; hence, the availability of safe and effective vaccines is of utmost importance. Vaccines intended for application in developing countries must also be thermally stable, since the infrastructure needed to maintain a cold chain in those countries is usually lacking. Porvac® is a second-generation subunit marker vaccine against CSF that has demonstrates to be safe and protective. Previous studies have also shown that the vaccine is stable for 1 week at 37 oC and have a shelf life of at least 36 months at 2–8 oC. The aim of this work was to further explore the accelerated stability of Porvac® by assessing the physicochemical properties of the emulsion, and the safety and immunogenicity of the vaccine subjected to more drastic conditions of thermal stress: (1) 25 oC for 12 months; (2) 30oC and 37 oC for one month and (3) 15 days at 37 °C after the cap of the vials had been needle-punctured.ResultsThe vaccine subjected to all these conditions did not show significant changes in the physicochemical properties of the emulsion; did not produce local or systemic adverse reactions in pigs, and the chromatographic profile of the recovered antigen was preserved. All vaccinated swine developed neutralizing antibody titers ≥ 1:1000 at 28 days post vaccination.ConclusionsPorvac® is stable in all the experimental conditions tested, even after cap puncture, and retains the capacity to induce high titers of neutralizing antibodies, well above the threshold of protection. These results reinforce the robustness of the vaccine, and support its use as a very attractive alternative to modified live vaccines in developing countries endemic for CSF.

Tackling immunosuppression by Neisseria gonorrhoeae to facilitate vaccine design.

Gonorrhoea, caused by Neisseria gonorrhoeae, is a common sexually transmitted infection. Increasing multi-drug resistance and the impact of asymptomatic infections on sexual and reproductive health underline the need for an effective gonococcal vaccine. Outer membrane vesicles (OMVs) from Neisseria meningitidis induce modest cross-protection against gonococcal infection. However, the presence of proteins in OMVs derived from N. gonorrhoeae that manipulate immune responses could hamper their success as a vaccine. Here we modified two key immunomodulatory proteins of the gonococcus; RmpM, which can elicit 'blocking antibodies', and PorB, an outer membrane porin which contributes to immunosuppression. As meningococcal PorB has adjuvant properties, we replaced gonococcal PorB with a meningococcal PorB. Immunisation with OMVs from N. gonorrhoeae lacking rmpM and expressing meningococcal porB elicited higher antibody titres against model antigens in mice compared to OMVs with native PorB. Further, a gonococcal protein microarray revealed stronger IgG antibody responses to a more diverse range of antigens in the Nm PorB OMV immunised group. Finally, meningococcal PorB OMVs resulted in a Th1-skewed response, exemplified by increased serum IgG2a antibody responses and increased IFNɣ production by splenocytes from immunised mice. In summary, we demonstrate that the replacement of PorB in gonococcal OMVs enhances immune responses and offers a strategy for gonococcal vaccine development.

Comparison of antibody responses of heterologous and homologous Covid-19 booster vaccination: an observational study.

Pakistan has been seriously affected by the COVID-19 pandemic, with numerous waves of infection. Using different vaccine and booster doses was a key component to control and combat this pandemic. This study aims to monitor the heterologous and homologous booster vaccination doses that generate immune responses in healthy adults after 9 months of vaccination. In this cross-sectional, observational study a total of 173 samples were collected. Participants from both genders (Male and Female) between the ages of 18 to 25 years were enrolled for the study. Participants who had booster shots of homologous Sinopharm BBIBP CorV and heterologous Pfizer-BioNTech vaccines were included only, with the use of a Roche Cobas-e601 analyzer, the antibody titers in the blood serum were quantified by the ECLIA method. IBM SPSS 22 was utilized for descriptive statistical analysis and P< 0.05 was considered significant. In this study the IgG antibody levels were measured against the full length of receptor binding domain (RBD) of the spike (S) protein. The mean antibody titer in the Pfizer group was 9764 ± 10976 U/mL and 5762 ± 4302 U/mL in the Sinopharm group. The Mean IgG antibody levels of the Pfizer-vaccinated group were significantly higher than the Sinopharm-vaccinated group (P=0.000, each). Comparing the Sinopharm BBIBP CorV booster dosage to the Pfizer booster, Pfizer BNT162b2demonstrated a stronger immune response. However, there were no immunological gender-specific significant differences. The administration of a third dosage of Pfizer BNT162b2 after two doses of BBIBP CorV. The administration of a third dosage of Pfizer BNT162b2 after two doses of BBIBP-CorV is recommended to boost the humoral immune response in the general population while there was no gender-specific difference observed. More effectiveness can be attained by administering additional doses due to the antibody decay.

Immunity Dynamics of Neisseria meningitidis Serogroups ACYW from Birth and Following Vaccination.

Background: Serosurveillance of epidemic cerebrospinal meningitis (ECM) in healthy individuals is crucial for assessing disease risk and evaluating the effectiveness of vaccinations. However, this practical work is rare in China. Methods: We conducted cross-section serosurveillance in Guangzhou, Zhanjiang, and Heyuan in Guangdong Province, measuring Anti-Nm IgG with serogroups A, C, Y, and W, and analyzed the trends using a generalized additive model (GAM). Results: During 2019-2022, 7752 participants were included. The overall antibody positivity rate for serogroups A, C, Y, and W were 60.75%, 15.51%, 32.83%, and 14.56%, respectively. High Anti-Nm IgG was in children aged 0-5 and 5-10 years old. Geometric mean concentrations (GMCs) of Anti-Nm IgG were higher and correlated positively with vaccine doses compared with unvaccinated individuals. The GMC showed a consistent decrease trend in the vaccinated and a U-shaped curve in populations. The declined rates of GMC were 1.59 (95% CI: 1.03, 2.14) µg/mL, 1.65 (95% CI: 1.28, 2.03), 0.62 (95% CI: 0.22, 1.03), and 0.31 (95% CI: 0.08, 0.53) µg/mL per year for serogroups A, C, Y, and W, respectively. Conclusions: There were differences in antibody positivity rate and GMC for the four serogroups of ECM in the healthy individuals of Guangdong Province, with serogroup A showing the highest, and the demographic differences highlighted the high seroprevalence of Neisseria meningitidis in younger people. The variable prevalence rates among serogroups A, C, Y, and W and the observed decline in antibody titers underscore the need for adjustments in the immunization program targeting the meningococcal vaccine.

Possible rapid reduction of anti-RBD antibody titre after SARS-CoV-2 mRNA vaccination in pregnant women: Multicentre prospective study.

Pregnant women are at increased risk for severe illness associated with coronavirus disease 2019 (COVID-19) compared to nonpregnant women. The aim of this multicenter prospective study was to assess the current COVID-19 vaccination status of pregnant women in the southern Osaka district and to compare their antibody titers with those of nonpregnant women. Serum antibody titers of anti-NCP antibodies (antibodies against the SARS-CoV-2 nucleocapsid) and anti-RBD antibodies (the receptor binding domain of the S1 subunit of the spike protein) were evaluated in 753 pregnant women at 34-35 weeks of gestation from October 2021 to March 2022. Anti-RBD antibody titre was also investigated in 1003 health care workers at Kindai University hospital 3 and 6 months after a second dose of the vaccine from March 2021 to April 2021. 519 (68.9%) pregnant women were vaccinated during pregnancy, of whom 497 (95.8%) received two doses. The COVID-19 infection rate calculated from the number of pregnant women with a positive anti-NCP antibody titre or with confirmed diagnosis was 5.1% (12/234) in the unvaccinated and 3.5% (18/519) in the vaccinated. The estimated half-life calculated from anti-RBD antibody titers and the number of days between vaccination and antibody testing was 39.9 days. The antibody titre and half-life in pregnant women were significantly lower and shorter than in nonpregnant women aged 20-39 years (109.4 days). Our study showed that pregnant women may have lower vaccine-acquired COVID-19 immunity than nonpregnant women.