Measurement Of Antibody Levels Research Articles

A statistically established reference value determined for the Vaxarray Coronavirus (CoV) seroassay to characterize vaccination and natural infection

Serological diagnostic tests are available that measure antibody levels against SARS-CoV-2 antigens. We utilized the Vaxarray Coronavirus (CoV) seroassay, which measures SARS-CoV-2 IgG antibodies against the full-length spike protein (FLS), receptor binding domain (RBD), and S2 extracellular domain (ECD). Previous serological studies have used reference values that have not been validated and require many samples. Here, we show statistically established reference values determined using the upper tail of the Student t-distribution method. The target population was any personnel age 18 years and older working on a U.S. Navy ship, and vaccinated with Wuhan variant. The relative fluorescence mean (RFM) reference values for the full-length spike protein, RBD, and S2 ECD were 17,731, 13,990 and 9096, respectively. By using generalized non-parametric regression and reference values for the RBD spike protein and S2 ECD of SARS-CoV-2, this study was able to distinguish vaccine-mediated immune responses from natural infections. We provide the method and statistical code as a resource to determine future reference values for other serological assays.

High-Throughput Screening Assay for Convalescent Sera in COVID-19: Efficacy, Donor Selection, and Variant Neutralization.

Convalescent sera, rich in pathogen-specific antibodies, offers passive immunity to patients with infectious diseases. Screening assays using convalescent sera are crucial for evaluating therapeutic efficacy, selecting suitable serum donors, and standardizing assays. They measure antibody levels, neutralizing potential, and specificity against viruses like SARS-CoV-2, ensuring therapeutic serum contains potent antibodies. Standardized procedures enable reliable results and wider adoption of serum therapy for COVID-19. We have developed a high-content image-based assay for screening convalescent sera against SARS-CoV-2 variants. Using various cell lines, we identified optimal candidates, employed immunofluorescence to visualize infected cells, and assessed neutralizing antibody efficacy. Screening convalescent sera for therapeutic potential identified neutralizing activity against SARS-CoV-2 variants. Dose-response analysis showed variable neutralizing activity, with some sera exhibiting broad neutralization. Additionally, we explored the synergy between neutralizing sera and β-d-N4-hydroxycytidine (NHC), an initial metabolite of molnupiravir. These assays enhance serum therapy's benefits for COVID-19 treatment and aid in understanding neutralizing activity against SARS-CoV-2 variants, addressing viral challenges.

Patients taking benralizumab, dupilumab, or mepolizumab have lower postvaccination SARS-CoV-2 immunity

Biologic therapies inhibiting the IL-4 or IL-5 pathways are very effective in the treatment of asthma and other related conditions. However, the cytokines IL-4 and IL-5 also play a role in the generation of adaptive immune responses. Although these biologics do not cause overt immunosuppression, their effect in primary severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization has not been studied completely. Our aim was to evaluate the antibody and cellular immunity after SARS-CoV-2 mRNA vaccination in patients on biologics (PoBs). Patients with severe asthma or atopic dermatitis who were taking benralizumab, dupilumab, or mepolizumab and had received the initial dose of the 2-dose adult SARS-CoV-2 mRNA vaccine were enrolled in a prospective, observational study. As our control group, we used a cohort of immunologically healthy subjects (with no significant immunosuppression) who were not taking biologics (NBs). We used a multiplexed immunoassay to measure antibody levels, neutralization assays to assess antibody function, and flow cytometry to quantitate Spike-specific lymphocytes. We analyzed blood from 57 patients in the PoB group and 46 control subjects from the NB group. The patients in the PoB group had lower levels of SARS-CoV-2 antibodies, pseudovirus neutralization, live virus neutralization, and frequencies of Spike-specific B and CD8 T cells at 6 months after vaccination. In subgroup analyses, patients with asthma who were taking biologics had significantly lower pseudovirus neutralization than did subjects with asthma who were not taking biologics. The patients in the PoB group had reduced SARS-CoV-2-specific antibody titers, neutralizing activity, and virus-specific B- and CD8 T-cell counts. These results have implications when considering development of a more individualized immunization strategy in patients who receive biologic medications blocking IL-4 or IL-5 pathways.

Alzheimer's disease risk associated with changes in Epstein-Barr virus nuclear antigen 1-specific epitope targeting antibody levels

BackgroundAlzheimer's disease (AD) is a neurodegenerative disorder influenced by age, sex, genetic factors, immune alterations, and infections. Multiple lines of evidence suggest that changes in antibody response are linked to AD pathology. MethodsTo elucidate the mechanisms underlying AD development, we investigated antibodies that target autoimmune epitopes using high-resolution epitope microarrays. Our study compared two groups: individuals with AD (n = 19) and non-demented (ND) controls (n = 19). To validate the results, we measured antibody levels in plasma samples from AD patients (n = 96), mild cognitive impairment (MCI; n = 91), and ND controls (n = 97). To further explore the invlovement of EBV, we performed epitope masking immunofluorescence microscopy analysis and tests to induce lytic replication using the B95–8 cell line. ResultsIn this study, we analyzed high-resolution epitope-specific serum antibody levels in AD, revealing significant disparities in antibodies targeting multiple epitopes between the AD and control groups. Particularly noteworthy was the significant down-regulation of antibody (anti-DG#29) targeting an epitope of Epstein-Barr virus nuclear antigen 1 (EBNA1). This down-regulation increased AD risk in female patients (odds ratio up to 6.6), but not in male patients. Our investigation further revealed that the down-regulation of the antibody (anti-DG#29) is associated with EBV reactivation in AD, as indicated by the analysis of EBV VCA IgG or IgM levels. Additionally, our data demonstrated that the epitope region on EBNA1 for the antibody is hidden during the EBV lytic reactivation of B95–8 cells. ConclusionOur findings suggest a potential relationship of EBV in the development of AD in female. Moreover, we propose that antibodies targeting the epitope (DG#29) of EBNA1 could serve as valuable indicators of AD risk in female.

Persistence of SARS-COV-2-specific T cell responses for over 12 months in vaccinated population with no measurable levels of anti-S antibodies

Persistence of SARS-COV-2-specific T cell responses for over 12 months in vaccinated population with no measurable levels of anti-S antibodies

Rapid loss of maternal immunity and increase in environmentally mediated antibody generation in urban gulls

Monitoring pathogen circulation in wildlife sentinel populations can help to understand and predict the spread of disease at the wildlife-livestock-human interface. Immobile young provide a useful target population for disease surveillance, since they can be easily captured for sampling and their levels of antibodies against infectious agents can provide an index of localized circulation. However, early-life immune responses include both maternally-derived antibodies and antibodies resulting from exposure to pathogens, and disentangling these two processes requires understanding their individual dynamics. We conducted an egg-swapping experiment in an urban-nesting sentinel seabird, the yellow-legged gull, and measured antibody levels against three pathogens of interest (avian influenza virus AIV, Toxoplasma gondii TOX, and infectious bronchitis virus IBV) across various life stages, throughout chick growth, and between nestlings raised by biological or non-biological parents. We found that levels of background circulation differed among pathogens, with AIV antibodies widely present across all life stages, TOX antibodies rarer, and IBV antibodies absent. Antibody titers declined steadily from adult through egg, nestling, and chick stages. For the two circulating pathogens, maternal antibodies declined exponentially after hatching at similar rates, but the rate of linear increase due to environmental exposure was significantly higher in the more prevalent pathogen (AIV). Differences in nestling antibody levels due to parental effects also persisted longer for AIV (25 days, vs. 14 days for TOX). Our results suggest that yellow-legged gulls can be a useful sentinel population of locally transmitted infectious agents, provided that chicks are sampled at ages when environmental exposure outweighs maternal effects.

Within-host bayesian joint modeling of longitudinal and time-to-event data of Leishmania infection.

The host immune system plays a significant role in managing and clearing pathogen material during an infection, but this complex process presents numerous challenges from a modeling perspective. There are many mathematical and statistical models for these kinds of processes that take into account a wide range of events that happen within the host. In this work, we present a Bayesian joint model of longitudinal and time-to-event data of Leishmania infection that considers the interplay between key drivers of the disease process: pathogen load, antibody level, and disease. The longitudinal model also considers approximate inflammatory and regulatory immune factors. In addition to measuring antibody levels produced by the immune system, we adapt data from CD4+ and CD8+ T cell proliferation, and expression of interleukin 10, interferon-gamma, and programmed cell death 1 as inflammatory or regulatory factors mediating the disease process. The model is developed using data collected from a cohort of dogs naturally exposed to Leishmania infantum. The cohort was chosen to start with healthy infected animals, and this is the majority of the data. The model also characterizes the relationship features of the longitudinal outcomes and time-to-death due to progressive Leishmania infection. In addition to describing the mechanisms causing disease progression and impacting the risk of death, we also present the model's ability to predict individual trajectories of Canine Leishmaniosis (CanL) progression. The within-host model structure we present here provides a way forward to address vital research questions regarding the understanding of the progression of complex chronic diseases such as Visceral Leishmaniasis, a parasitic disease causing significant morbidity worldwide.

A phase 4, open-label study to evaluate the safety and immunogenicity of DTaP5-HBV-IPV-Hib in children previously vaccinated with DTaP2-HBV-IPV-Hib or DTaP5-HBV-IPV-Hib (V419-016)

ABSTRACT DTaP5-HBV-IPV-Hib (Vaxelis®) is a hexavalent combination vaccine (HV) indicated in infants and toddlers for the prevention of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis, and invasive disease due to Haemophilus influenzae type b. Switching between HVs during the childhood vaccination series is sometimes necessary due to, for example, vaccine availability, health-care provider preference, and/or tender awards. The purpose of this study was to describe the safety, tolerability, and immunogenicity of a booster dose of Vaxelis® in participants who previously received a primary infant series of either DTaP2-HBV-IPV-Hib (Hexyon®) or Vaxelis®. Healthy participants approximately 11–13 months of age who previously received a two-dose primary series of Hexyon® (HHV group) or Vaxelis® (VVV group) all received a Vaxelis® booster dose. Immunogenicity was evaluated by measuring antibody levels to individual vaccine antigens approximately 30 days following booster vaccination. Safety was evaluated as the proportion of participants with adverse events (AEs). The proportions of participants with antibody-specific responses for antigens contained in both Vaxelis® and Hexyon® at 30 days post-toddler-booster vaccination with Vaxelis® were comparable between groups, and higher in the VVV group for Vaxelis® antigens PRN and FIM2/3. The overall proportions of participants with AEs were generally comparable between groups. Following a booster dose of Vaxelis®, immune responses were comparable between groups for all shared antigens, and higher in the VVV group for antigens found only in Vaxelis®. The booster was well tolerated in both groups. These data support the use of Vaxelis® as a booster in mixed HV regimens.

Evaluation of SARS-CoV-2 Antibody Levels in Pharmacists and Pharmacy Staff Following CoronaVac Vaccination.

The aim of this study was to determine the seropositivity rate of pharmacists and pharmacy staff after the administration of two doses of the CoronaVac-SinoVac vaccine and to assess changes in their antibody levels according to sociodemographic characteristics. This descriptive study was conducted between June 04, 2021 and September 30, 2021 in pharmacies located in Istanbul, Türkiye. The results of self-initiated immunoglobulin (Ig) G testing of the pharmacists and pharmacy staff, conducted at diagnostic laboratories contracted by the Istanbul Chamber of Pharmacists, were obtained using an online data collection tool. IgG measurements taken from 15 days up to 120 days after the two vaccine doses were included in the study. Participants were asked whether they smoked, had any chronic diseases (hypertension, chronic obstructive pulmonary disease, asthma, diabetes, etc.), or took any medications. Subgroup analyses were performed for each method used to measure antibody levels. The study included 329 pharmacists/pharmacy staff (298 pharmacists and 31 pharmacy staff). The mean age of the participants was 49.7 ± 13.7 years, and 71.4% were female. The antibody positivity of the 329 participants was 94.9% following the two doses. The positivity rate was 95.4% in participants under 65 years of age, whereas it was 91.8% in those aged 65 years and over. There was no significant difference in the mean age between those with positive and negative antibody results (p > 0.05). Although antibody levels were lower older people, smokers, and those with chronic diseases, this difference was not statistically significant (p > 0.05). Seropositivity developed following the administration of two doses of CoronaVac-Sinovac vaccines. IgG antibody levels were lower in older adults, smokers, and those with chronic diseases, although not to a statistically significant extent. Further studies are needed to better understand the reasons for the different immunological responses to COVID-19.

Persistence of Antibody Response Against SARS-CoV-2 After Vaccination

SARS-CoV-2 is the causative agent of the disease known as COVID-19. COVID-19 is spreading very fast around the world. One of the immune responses that play a role in against SARS-CoV-2 infection is the production of antibodies, which is 3 weeks after infection. Where within 3 weeks after infection, antibodies will be produced against RBD and the S1 and S2 domains in glycoprotein S and nucleocapsid protein N. The ability of an antibody to inhibit viral infection is determined by its level or titer. This study aims to determine the description of antibody levels against SARS-CoV-2 after vaccination. This type of research is descriptive research. Measurement of antibody levels for SRBD SARS-CoV-2 was carried out using the CLIA method using the MAGLUMI tool. Of the 30 respondents, 23 people had received the third vaccine. The results of this study showed that the average level of SRBD antibodies against SARS-CoV-2 in respondents with 2 doses of vaccine (1.063,786 BAU/mL) was higher than in respondents with 3 doses of vaccine (535.651 BAU/mL). Vaccine intervals of more than 6 months (908.338 BAU/mL) have higher antibody levels than respondents with vaccine intervals of 1-6 months (228.006 BAU/mL). The conclusion of this study is the highest antibody titers are produced >6 months after vaccination, antibody titers are still detectable after 12 months of vaccination, and for further research, it can be measured antibody levels against SARS-CoV-2 from people who have got vaccination for a duration of 2 years or more.

Riding high: seroprevalence of SARS-CoV-2 after 4 pandemic waves in Manitoba, Canada, April 2020–February 2022

BackgroundCanada is emerging from the largest SARS-CoV-2 Omicron wave to date, with over 3.3 million confirmed cases. Unfortunately, PCR confirmed cases illuminate only a small portion of infections in the community and underestimate true disease burden. Population based seroprevalence studies, which measure antibody levels against a virus can more accurately estimate infection rates in the community and identify geographical and epidemiological trends to inform public health responses.MethodsThe Manitoba COVID-19 Seroprevalence (MCS) study is a population-based cross-sectional study to assess the prevalence of SARS-CoV-2 antibodies across the province. Residual convenience specimens (n = 14,901) were tested for anti-SARS-CoV-2 nucleocapsid and spike IgG antibodies from April 1, 2020 to February 31, 2022. We estimated the monthly and cumulative prevalence using an exponential decay model, accounting for population demographics, sensitivity/specificity, and antibody waning. This approach generated estimates of natural infection as well as total antibody including vaccine-induced immunity within the community.FindingsAfter four waves of the pandemic, 60.1% (95%CI-56.6–63.7) of Manitobans have generated SARS-CoV-2 antibodies due to natural exposure independent of vaccination. Geographical analysis indicates a large portion of provincial prevalence stems from increased transmission in the Northern (92.3%) and Southern (71.8%) regional health authorities. Despite the high mortality rates reported by Manitoba, infection fatality ratios (IFR) peaked at 0.67% and declined to 0.20% following the Omicron wave, indicating parity with other national and international jurisdictions. Manitoba has achieved 93.4% (95%CI- 91.5–95.1) total antibody when including vaccination.InterpretationOur data shows that more than 3 in 5 Manitobans have been infected by SARS-CoV-2 after four waves of the pandemic. This study also identifies key geographical and age specific prevalence rates that have contributed greatly to the overall severity of the pandemic in Manitoba and will inform jurisdictions considering reduction of public health measures.

Persistence of T-Cell Immunity Responses against SARS-CoV-2 for over 12 Months Post COVID-19 Infection in Unvaccinated Individuals with No Detectable IgG Antibodies.

Immune response to SARS-CoV-2 is crucial for preventing reinfection or reducing disease severity. T-cells' long-term protection, elicited either by COVID-19 vaccines or natural infection, has been extensively studied thus far; however, it is still attracting considerable scientific interest. The aim of the present epidemiological study was to define the levels of T-cellular immunity response in a specific group of unvaccinated individuals from the general population with a prior confirmed COVID-19 infection and no measurable levels of IgG antibodies. We performed a retrospective descriptive analysis of data collected from the medical records of consecutive unvaccinated individuals recovered from COVID-19, who had proceeded to a large private medical center in the Attica region from September 2021 to September 2022 in order to be examined on their own initiative for SARS-CoV-2 T-cell immunity response. The analysis of T-cell responses was divided into three time periods post infection: Group A: up to 6 months; Group B: 6-12 months; Group C: >12 months. The SARS-CoV-2 T-cell response was estimated against spike (S) and nucleocapsid (N) structural proteins by performing the T-SPOT. COVID test methodology. SARS-CoV-2 IgG antibody levels were measured by the SARS-CoV-2 IgG II Quant assay (Abbott Diagnostics). A total of 182 subjects were retrospectively included in the study, 85 females (46.7%) and 97 (53.3%) males, ranging from 19 to 91 years old (mean 50.84 ± 17.2 years). Among them, 59 (32.4%) had been infected within the previous 6 months from the examination date (Group A), 69 (37.9%) had been infected within a time period > 6 months and <1 year (Group B) and 54 (29.7%) had been infected within a time period longer than 1 year from the examination date (Group C). Among the three groups, a positive T-cell reaction against the S antigen was reported in 47/58 (81%) of Group A, 61/69 (88.4%) of Group B and 40/54 (74.1%) of Group C (chi square, p = 0.27). T-cell reaction against the N antigen was present in 45/58 (77.6%) of Group A, 61/69 (88.4%) of Group B and 36/54 (66.7%) of Group C (chi square, p = 0.02). The median Spot-Forming Cells (SFC) count for the S antigen was 18 (range from 0-160) in Group A, 19 (range from 0-130) in Group B and 17 (range from 0-160) in Group C (Kruskal-Wallis test, p = 0.11; pairwise comparisons: groups A-B, p = 0.95; groups A-C, p = 0.89; groups B-C, p = 0.11). The median SFCs count for the N antigen was 14.5 (ranging from 0 to 116) for Group A, 24 (ranging from 0-168) in Group B and 16 (ranging from 0-112) for Group C (Kruskal-Wallis test, p = 0.01; pairwise comparisons: groups A-B, p = 0.02; groups A-C, p = 0.97; groups B-C, p = 0.03). Our data suggest that protective adaptive T-cellular immunity following natural infection by SARS-CoV-2 may persist for over 12 months, despite the undetectable humoral element.

1741. A Phase 4, Open-label, Multicenter Study to Evaluate the Safety, Tolerability, and Immunogenicity of Vaxelis™ in Healthy Children Previously Vaccinated With a 2-Dose Primary Infant Series of Either Vaxelis™ or Hexyon™ (V419-016)

Abstract Background Vaxelis™ is a hexavalent combination vaccine (HCV) indicated in infants and toddlers for the prevention of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis, and invasive disease due to Haemophilus influenzae type b. In practice, switching between HCVs during the childhood vaccination series is sometimes necessary due to vaccine availability, health care provider preference, tender awards, or other reasons. The various HCVs differ in the types of antigens used, which may affect immunogenicity and reactogenicity. The use of Vaxelis™ as a booster dose after another HCV has not previously been studied in a clinical trial. The purpose of this study was to describe the safety, tolerability, and immunogenicity of a booster dose of Vaxelis™ in toddlers who previously received a primary infant series of either Vaxelis™ or Hexyon™. Methods Healthy participants approximately 11 to 13 months of age who previously received a two-dose primary series of Vaxelis™ (VVV group) or Hexyon™ (HHV group) at approximately 2 and 4 months of age all received a Vaxelis™ booster dose. Safety was evaluated as the proportion of participants with adverse events (AEs). Immunogenicity was evaluated by measuring antibody levels to individual vaccine antigens approximately 30 days following booster vaccination. Results Participant characteristics were comparable between groups (VVV group n=85; HHV group n=82). The overall proportions of participants with AEs­─including injection-site, systemic, vaccine-related, and serious AEs─were generally comparable between groups. The proportions of participants with antibody-specific responses for antigens contained in both Vaxelis™ and Hexyon™ at 30 days postvaccination with Vaxelis™ were comparable between groups and higher in the VVV group for antigens FIM2/3 and PRN found only in Vaxelis™ (Table 1).Table 1.Proportions of participants meeting specified Vaxelis™ antigen responses at 30 days postvaccination Conclusion A booster dose of Vaxelis™ was well tolerated following a primary series of Hexyon™ with a safety profile similar to a 3-dose series of Vaxelis™. Immune responses were comparable for all shared antigens and higher for those found only in Vaxelis™. These data support the use of Vaxelis™ as a booster in mixed HCV regimens. Disclosures Andrea Guerra, MD, Merck Sharp &amp; Dohme LLC - United Kingdom: employee|Merck Sharp &amp; Dohme LLC - United Kingdom: Stocks/Bonds Federico Martinon-Torres, MD, PhD, Assoc. Prof, Ablynx, Gilead, Regeneron, Roche, Abbott and MedImmune: Honoraria|Ablynx, Gilead, Regeneron, Roche, Abbott and MedImmune: principal investigator|Astra Zeneca, GSK, Pfizer Inc, Sanofi, MSD, Seqirus, Moderna, Novavax, Biofabri, and Janssen: Advisor/Consultant|Astra Zeneca, GSK, Pfizer Inc, Sanofi, MSD, Seqirus, Moderna, Novavax, Biofabri, and Janssen: Board Member|Astra Zeneca, GSK, Pfizer Inc, Sanofi, MSD, Seqirus, Moderna, Novavax, Biofabri, and Janssen: Honoraria|Astra Zeneca, GSK, Pfizer Inc, Sanofi, MSD, Seqirus, Moderna, Novavax, Biofabri, and Janssen: speaker and investigator Courtney Lambeth, BS, Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: employee|Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: Stocks/Bonds Ziqiang Chen, PhD, Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: employee|Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: Stocks/Bonds Jessie Lumley, MA, Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: employee|Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: Stocks/Bonds David Johnson, MD, MPH, Sanofi: employee Marissa B. Wilck, MD, Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: employee|Merck Sharp &amp; Dohme LLC, a subsidiary of Merck &amp; Co., Inc., Rahway, NJ, USA: Stocks/Bonds

Comparison of anti-nucleocapsid antibody assays for the detection of SARS-CoV-2 Omicron vaccine breakthroughs after various intervals since the infection.

Antibody assays with the nucleocapsid (NC) protein as the target antigen can identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections when polymerase chain reaction (PCR) analyses are unavailable. Regarding the kinetics of NC-specific antibodies, vaccine breakthroughs with Omicron subvariants may differ from infections with the ancestral wild-type virus. Therefore, we evaluated which assays have the highest sensitivity for detecting NC-specific antibodies after various intervals since breakthrough infections with an Omicron subvariant. The study included 279 samples from vaccinated subjects who experienced PCR-confirmed Omicron breakthrough infections between 21 and 266 days before sampling. The samples were comparatively assessed with the Elecsys® Anti-SARS-CoV-2 N (Roche), the Anti-SARS-CoV-2-NCP-ELISA (Euroimmun), the recomLine SARS-CoV-2 IgG (Mikrogen), and the SARS-CoV-2 ViraChip IgG assays (Viramed). In the whole cohort, the Elecsys® Anti-SARS-CoV-2 N assay displayed the highest sensitivity (93%, p < 0.0001), followed by the recomLine SARS-CoV-2 IgG assay (70%), the SARS-CoV-2 ViraChip IgG assay (41%) and the Anti-SARS-CoV-2-NCP-ELISA (35%). Although measured antibody levels and time-dependent sensitivities differed, the extent of the antibody decrease was similar among all assays. As demonstrated by this study, manufacturer-dependent differences in the sensitivities of NC-specific antibody assays should be considered when serology is applied to link previous SARS-CoV-2 infections with potential post-COVID sequelae.

Transplacental transfer efficiency of maternal antibodies against influenza A(H1N1)pdm09 virus and dynamics of naturally acquired antibodies in Chinese children: a longitudinal, paired mother–neonate cohort study

The 2009 pandemic H1N1 influenza A virus (A(H1N1)pdm09 virus) evolves rapidly and has continued to cause severe infections in children since its emergence in 2009. We aimed to characterise the kinetics of maternally and naturally acquired antibodies against historical A(H1N1)pdm09 strains and to assess the extent to which the response to heterologous strains following infection or vaccination affects observed A(H1N1)pdm09 strain-specific antibody titres in a Chinese paediatric population. In this retrospective study, we used residual serum samples from 528 mother-neonate pairs from a non-interventional, longitudinal cohort study in southern China conducted from Sept 20, 2013, to Aug 24, 2018, from six local hospitals in Anhua County, Hunan Province, China. Mother-neonate pairs were eligible for inclusion if the neonates were born after Sept 20, 2013, and their mothers had resided in the study sites for at least 3 months. We tested samples with a haemagglutination inhibition (HAI) assay to measure antibody levels against three historical A(H1N1)pdm09 strains that were antigenically similar to the strains that circulated during the 2009 pandemic (A/Hunan-Kaifu/SWL4204/2009 [SWL4204/09 strain], A/Hunan-Daxiang/SWL1277/2016 [SWL1277/16 strain], and A/Hunan-Yanfeng/SWL185/2018 [SWL185/18 strain]). We also determined the seroprevalence, geometric mean titres (GMTs), transfer ratio of maternal antibodies, and the dynamics of maternally and naturally acquired antibodies in children, from birth to 3 years of age. 1066 mother-neonate pairs were enrolled in the original cohort between Sept 20, 2013, and Oct 14, 2015. Of these, 528 pairs (523 mothers, 528 neonates) were selected for the present study. The median age of the mothers was 25 years (IQR 23 to 29). 291 (55%) of 528 children were boys and 237 (45%) were girls, and most children (452 [86%]) were breastfed before the age of 6 months. The GMTs and the seroprevalence for the SWL4204/09 strain were higher than those for the SWL1277/16 and SWL185/18 strains among mothers (GMTs: 10·4 [95% CI 9·8 to 11·1] vs 9·3 [8·7 to 9·8] vs 8·0 [7·5 to 8·4], p<0·0001; seroprevalence: 11·1% [95% CI 8·5 to 14·1] vs 6·9% [4·9 to 9·4] vs 4·6% [3·0 to 6·8], p=0·0003) and among neonates (GMTs: 10·7 [10·0 to 11·5] vs 9·4 [8·8 to 10·0] vs 8·1 [7·6 to 8·6], p<0·0001; seroprevalence: 13·4% [10·7 to 16·7] vs 8·7% [6·5 to 11·5] vs 6·1% [4·2 to 8·5], p=0·0002). Regardless of the A(H1N1)pdm09-specific strain, maternal antibodies could be transferred efficiently via the placenta (mean transfer ratios: 1·10 for SWL4204/09 vs 1·09 for SWL1277/16 vs 1·06 for SWL185/18; p=0·93). The A(H1N1)pdm09 strain-specific antibodies waned below the protective threshold of 1:40 within 2 months after birth. After maternal antibody waning, there were periodic increases and decreases in HAI antibody titres against three A(H1N1)pdm09 strains, and such increases were all significantly associated with a higher immune response to heterologous strains. Vaccination against the SWL4204/09 strain was associated with a poor response to the SWL185/18 strain (β-0·20, 95% CI -0·28 to -0·13; p<0·0001). Our findings suggest low pre-existing immunity against influenza A(H1N1)pdm09 virus among unvaccinated Chinese adult female and paediatric populations. This evidence, together with the rapid decay of maternal antibodies and the observed cross-reactivity among different A(H1N1)pdm09 strains, highlights the importance of accelerating maternal and paediatric influenza vaccination in China. The Key Program of the National Natural Science Foundation of China. For the Chinese translation of the abstract see Supplementary Materials section.

A Study on Prevalence and Molecular Characterization of Spike Protein of SARS-COV2 in Pakistan

Objective: To examine the prevalence of antibody IgG/IgM and designing follow-up study of six months and to perform the molecular characterization and sequence analysis of spike protein of SARS-CoV-2.Study Design: Prevalence study. Place and Duration of the Study: The study was conducted in the Post-Graduate Lab of the National University of Medical Sciences (NUMS) Rawalpindi, Pakistan from January 2021 to June 2021.Methods: 112 suspected patients with mild and severe symptoms were tested by PCR (polymerase chain reaction) and all were positive. Antibody profiling of vaccinated and non-vaccinated patients was performed by enzyme-linked immunosorbent assay (ELISA) and followed up for up to six months.Results: Ten patients were identified as re-infected and were subsequently re-tested via PCR and DNA sequencing. The IgG/IgM of immunized patients was 11.87IU/mL and 3.87IU/mL in non-immunized individuals. Genomic analysis indicated that all the sequences belong to delta variant (21A and 21J sub-lineages). Mutations were observed in spike protein at I1169V, D950N in 21A and T951I and S254F in 21J sub-lineages.Conclusion: This study revealed the significance of measuring antibody levels among vaccinated and unvaccinated individuals. Additionally, mutations in the spike gene of the delta variant of SARS-CoV2 can influence the pathogen's mutation rate, leading to changes in its transmissibility and pathogenicity.&#x0D; How to cite this: Rizwan M, Ahad A, Aziz S, Lone NA, Naz T, Khan MB, Jafri L, Ali L. A Study on Prevalence and Molecular Characterization of Spike Protein of SARS-COV-2 in Pakistan. Life and Science. 2023; 4(4): 458-468. doi: http://doi.org/10.37185/LnS.1.1.400

Antibody response to SARS-CoV-2 vaccination or infection in a prospective cohort of children with neuroinflammatory diseases.

Immune medications affect antibody responses to SARS-CoV-2 vaccination in adults with neuroinflammatory disorders, but little is known about antibody responses in children with neuroinflammation and on immune treatments. Here we measure antibody levels in response to SARS-CoV-2 vaccination in children receiving anti-CD20 monoclonal antibodies, or fingolimod. Children under 18 years of age with pediatric-onset neuroinflammatory disorders who received at least two mRNA vaccines were included. Plasma samples were assayed for SARS-CoV-2 antibodies (spike, spike receptor binding domain-RBD, nucleocapsid) and neutralization antibodies. Seventeen participants with pediatric onset neuroinflammatory diseases were included: 12 multiple sclerosis, one neuromyelitis optica spectrum disorder, two MOG-associated disease, and two autoimmune encephalitis. Fourteen were on medications (11 on CD20 monoclonal antibodies-mAbs, one on fingolimod, one on steroids, one on intravenous immunoglobulin) and three were untreated. Nine patients also had pre-vaccination samples available. All participants had seropositivity to spike or spike RBD antibodies except for those receiving CD20 mAbs. However, this proportion was higher in children than in an adult MS patient cohort. The most significant contributor to antibody levels was duration of DMT. SARS-CoV-2 antibodies are decreased in children on CD20 monoclonal antibodies than on other treatments. Treatment duration associated with vaccination responses.

Long-term immunoprotection after live attenuated measles-mumps-rubella booster vaccination in children with juvenile idiopathic arthritis

IntroductionVaccines, especially live attenuated vaccines, in children with JIA pose a great challenge due to both potential lower immunogenicity and safety as a result of immunosuppressive treatment. For many years, in the Netherlands, JIA patients receive a measles-mumps-rubella (MMR) booster vaccine at the age of nine years as part of the national immunization program. ObjectivesTo study long-term humoral immunoprotection in a large cohort of JIA patients who received the MMR booster vaccine while being treated with immunomodulatory therapies at the Wilhelmina Children’s Hospital in Utrecht, the Netherlands. MethodsMMR-specific IgG antibody concentrations in stored serum samples of vaccinated JIA patients were determined with chemiluminescent microparticle immunoassays (CMIA). Samples were analyzed five years after MMR booster vaccination and at last available follow-up visit using both crude and adjusted analyses. Additional clinical data were collected from electronic medical records. ResultsIn total, 236 samples from 182 patients were analyzed, including 67 samples that were available five years post-vaccination, and an additional 169 samples available from last visits with a median duration after vaccination of 6.9 years (IQR: 2.8–8.8). Twenty-eight patients were using biologic disease-modifying antirheumatic drugs (bDMARDS) of whom 96% anti-TNF agents and 4% tocilizumab. Percentages of protective antibody levels against measles after five years were significantly lower for patients who used bDMARD therapy at vaccination compared to patients who did not: 60% versus 86% (P = 0.03). For mumps (80% versus 94%) and rubella (60% versus 83%) this difference did not reach statistical significance (P = 0.11 and P = 0.07, respectively). Antibody levels post-vaccination decreased over time, albeit not significantly different between bDMARD users and non-bDMARD users. ConclusionThe MMR booster vaccine demonstrated long-term immunogenicity in the majority of children with JIA from a large cohort, although lower percentages of protective measles antibody levels were observed in bDMARD users. Hence, it might be indicated to measure antibody levels at least five years after MMR booster vaccination in the latter group and advice an extra booster accordingly.

Factors affecting the immunogenicity of influenza vaccines in human

BackgroundThe influenza viruses pose a threat to human health and medical services, and vaccination is an important way to prevent infection. However, the effectiveness of influenza vaccines is affected by various aspects. This study aimed to explore factors related to the immune response to influenza vaccines.MethodsThe study was conducted from September 2019 to September 2021, and a total of 593 volunteers were recruited from the Center for Disease Control and Prevention in 3 provinces in China. The hemagglutination inhibition assay was used to measure antibody levels. The Chi-square test, multivariable logistic regression analysis, and sum-rank test were used to analyze the factors associated with influenza vaccine immune response.ResultsThe Chi-square test showed that seroconversion rates and response rate were associated with age group, vaccination history, chronic conditions, the frequency of colds, and region (P < 0.05). The multivariable logistic regression analysis showed that age was an important factor that affected participants’ seroconversion rates for A/H1N1, A/H3N2, B/Victoria, and response status (18–64 vs. ≤5: OR = 2.77, P < 0.001; ≥65 vs. ≤5: OR = 0.38, P = 0.01; 18–64 vs. ≤5: OR = 2.64, P = 0.03). Vaccination history was also an affecting factor for A/H1N1, B/Victoria, and response status (yes vs. no: OR = 0.4 / 0.44 / 0.25, P < 0.001). The frequency of colds and chronic conditions were also affecting factors for participants’ seroconversion rates and response levels to different degrees. The sum-rank test showed that the fold changes for A/H1N1, B/Victoria, and B/Yamagata were associated with age group and vaccination history (P < 0.01). The fold changes for A/H3N2 were associated with the frequency of colds (P < 0.05), and those for B/Victoria were associated with gender and chronic conditions (P < 0.05).ConclusionsVaccination history, age, health condition, and frequency of colds were important factors affecting the seroconversion rate of the influenza vaccine in human. There is a need for developing optimized vaccination strategies for vulnerable groups to improve the efficacy of influenza vaccines in human.

Short-Lived Antibody-Mediated Saliva Immunity against SARS-CoV-2 after Vaccination.

Knowledge about the effect of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on immunity reflected in the saliva is sparse. We examined the antibody response in saliva compared to that in serum 2 and 6 months after the first vaccination with the BNT162b2 vaccine. Four hundred fifty-nine health care professionals were included in a prospective observational study measuring antibody levels in saliva and corresponding serum samples at 2 and 6 months after BNT162b2 vaccination. Vaccinated, previously SARS-CoV-2-infected individuals (hybrid immunity) had higher IgG levels in saliva at 2 months than vaccinated, infection-naive individuals (P < 0.001). After 6 months, saliva IgG levels declined in both groups (P < 0.001), with no difference between groups (P = 0.37). Furthermore, serum IgG levels declined from 2 to 6 months in both groups (P < 0.001). IgG antibodies in saliva and serum correlated in individuals with hybrid immunity at 2 and 6 months (ρ = 0.58, P = 0.001, and ρ = 0.53, P = 0.052, respectively). In vaccinated, infection-naive individuals, a correlation was observed at 2 months (ρ = 0.42, P < 0.001) but not after 6 months (ρ = 0.14, P = 0.055). IgA and IgM antibodies were hardly detectable in saliva at any time point, regardless of previous infection. In serum, IgA was detected at 2 months in previously infected individuals. BNT162b2 vaccination induced a detectable IgG anti-SARS-CoV-2 RBD response in saliva at both 2 and 6 months after vaccination, being more prominent in previously infected than infection-naive individuals. However, a significant decrease in salivary IgG was observed after 6 months, suggesting a rapid decline in antibody-mediated saliva immunity against SARS-CoV-2, after both infection and systemic vaccination. IMPORTANCE Knowledge about the persistence of salivary immunity after SARS-CoV-2 vaccination is limited, and information on this topic could prove important for vaccine strategy and development. We hypothesized that salivary immunity would wane rapidly after vaccination. We measured anti-SARS-CoV-2 IgG, IgA, and IgM concentrations in saliva and serum in both previously infected and infection-naive individuals, 2 and 6 months after first vaccination with BNT162b2, in 459 hospital employees from Copenhagen University Hospital. We observed that IgG was the primary salivary antibody 2 months after vaccination in both previously infected and infection-naive individuals, but dropped significantly after 6 months. Neither IgA nor IgM was detectable in saliva at either time point. Findings indicate that salivary immunity against SARS-CoV-2 rapidly declines following vaccination in both previously infected and infection-naive individuals. We believe this study shines a light on the workings of salivary immunity after SARS-CoV-2 infection, which could prove relevant for vaccine development.