Pandemic influenza A(H1N1pdm09) vaccine induced high levels of influenza-specific IgG and IgM antibodies as analyzed by enzyme immunoassay and dual-mode multiplex microarray immunoassay methods

Advances in upconversion luminescence nanomaterial-based biosensor for virus diagnosis

Various infectious viruses have been posing a major threat to global public health, especially SARS-CoV-2, which has already claimed more than six million lives up to now. Tremendous efforts have been made to develop effective techniques for rapid and reliable pathogen detection. The unique characteristics of upconversion nanoparticles (UCNPs) pose numerous advantages when employed in biosensors, and they are a promising candidate for virus detection. Herein, this Review will discuss the recent advancement in the UCNP-based biosensors for virus and biomarkers detection. We summarize four basic principles that guide the design of UCNP-based biosensors, which are utilized with luminescent or electric responses as output signals. These strategies under fundamental mechanisms facilitate the enhancement of the sensitivity of UCNP-based biosensors. Moreover, a detailed discussion and benefits of applying UCNP in various virus bioassays will be presented. We will also address some obstacles in these detection techniques and suggest routes for progress in the field. These progressions will undoubtedly pose UCNP-based biosensors in a prominent position for providing a convenient, alternative approach to virus detection.

Assessment of S-Specific IgG and IgM Positive Rates in Healthy Hospital Staff Members Vaccinated with the Inactivated SARS-CoV-2 Vaccine

Widespread vaccination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine makes the assessment of antibodies' positive rates essential. In this study, a total of 378 hospital staff members vaccinated with the vaccine were selected as research subjects. Serum-specific IgG and IgM against the SARS-CoV-2 spike protein (S) were detected, and S-specific IgG and IgM positive rates were analyzed in different age and sex groups, as was the serological pattern of IgG/IgM. The positive rates of IgG and IgM were 92.06% and 44.44%, respectively. The percentage of both IgG and IgM positive (IgG⁺IgM⁺) was 43.92%. A total of 182 vaccinees (46.90%) were IgG positive and IgM negative (IgG⁺IgM^-), and 28 vaccinees (7.41%) were negative for both IgG and IgM (IgG^-IgM^-); 2 participants were positive for IgM alone (IgG^-IgM⁺). In sex subgroups, the rate of IgM positivity was significantly higher in the male group than in the female group (p = 0.027). In different age subgroups, positive rates for IgG in the young group were significantly higher than those in the other group (p = 0.035). Furthermore, ratios of sample values to cutoff values (S/CO values) for IgG in vaccinees who were S-specific IgG positive were compared, and the S/CO values of IgG were significantly higher in the younger group than in the other group (p < 0.001). When comparing the influence of sex on two specific serological patterns (IgG⁺IgM^- and IgG⁺IgM⁺), a significant difference in positivity rates was detected (p = 0.011). Male vaccinees were more likely than females to have an IgG⁺IgM⁺ pattern.

Clinical spectrum, risk factors, and outcomes of children with laboratory-confirmed influenza infection managed in a single tertiary hospital: A 6-year retrospective cohort study

BACKGROUND

Influenza is a highly contagious disease that causes severe illness each year. Data in the United Arab Emirates are scarce.

OBJECTIVES

To study the seasonality, morbidity, mortality rate, and comorbidities associated with confirmed influenza infection in a tertiary hospital in Al-Ain city, UAE.

METHODS

Retrospective study, from 2012 to 2017, of the electronic medical records in Tawam hospital, of children up to 15 years of age with laboratory-confirmed influenza infection.

RESULTS

There were 1392 children, with the highest number in 2017 (n = 461, 33%). The incidence peaked between October and March. The infection was more common between 1 and 11 years of age (n = 948, 68%). The overall prevalence of influenza A (n = 1144, 82%) was higher than influenza B (n = 276, 19.8%). One-third of the patients required admission. The commonest underlying comorbidity was asthma (n = 170, 12%). The two commonest complications were pneumonia (n = 165, 12%) and acute otitis media (n = 82, 6%).

CONCLUSION

Our findings serve as a benchmark for comparison with reports from other countries and need to be considered when reviewing the national vaccination program.

Monoclonal Antibody Targeting the HA191/199 Region of H1N1 Influenza Virus Mediates the Damage of Neural Cells

Vaccination is the most effective mean of preventing influenza virus infections. However, vaccination-induced adverse reactions of the nervous system, the causes of which are unknown, lead to concerns on the safety of influenza A vaccine. In this study, we used flow cytometry, cell ELISA, and immunofluorescence to find that H1-84 monoclonal antibody (mAb) against the191/199 region of the H1N1 influenza virus hemagglutinin (HA) protein binds to neural cells and mediates cell damage. Using molecular simulation software, such as PyMOL and PDB viewer, we demonstrated that the HA191/199 region maintains the overall structure of the HA head. Since the HA191/199 region cannot be removed from the HA structure, it has to be altered via introducing point mutations by site-directed mutagenesis. This will provide an innovative theoretical support for the subsequent modification the influenza A vaccine for increasing its safety.

A Combination of N and S Antigens With IgA and IgG Measurement Strengthens the Accuracy of SARS-CoV-2 Serodiagnostics

BACKGROUND

Primary diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is based on detection of virus RNA in nasopharyngeal swab samples. In addition, analysis of humoral immunity against SARS-CoV-2 has an important role in viral diagnostics and seroprevalence estimates.

METHODS

We developed and optimized an enzyme immunoassays (EIA) using SARS-CoV-2 nucleoprotein (N), S1 and receptor binding domain (RBD) of the viral spike protein, and N proteins from SARS, Middle East respiratory syndrome (MERS), and 4 low-pathogenic human CoVs. Neutralizing antibody activity was compared with SARS-CoV-2 IgG, IgA, and IgM EIA results.

RESULTS

The sensitivity of EIA for detecting immune response in COVID-19 patients (n = 101) was 77% in the acute phase and 100% in the convalescent phase of SARS-CoV-2 infection when N and RBD were used as antigens in IgG and IgA specific EIAs. SARS-CoV-2 infection significantly increased humoral immune responses against the 229E and NL63 N proteins. S1 and RBD-based EIA results had a strong correlation with microneutralization test results.

CONCLUSIONS

The data indicate a combination of SARS-CoV-2 S1 or RBD and N proteins and analysis of IgG and IgA immunoglobulin classes in sera provide an excellent basis for specific and sensitive serological diagnostics of COVID-19.

No evidence of autoimmunity to human OX1 or OX2 orexin receptors in Pandemrix-vaccinated narcoleptic children

Narcolepsy type 1, likely an immune-mediated disease, is characterized by excessive daytime sleepiness and cataplexy. The disease is strongly associated with human leukocyte antigen (HLA) DQB1∗06:02. A significant increase in the incidence of childhood and adolescent narcolepsy was observed after a vaccination campaign with AS03-adjuvanted Pandemrix influenza vaccine in Nordic and several other countries in 2010 and 2011. Previously, it has been suggested that a surface-exposed region of influenza A nucleoprotein, a structural component of the Pandemrix vaccine, shares amino acid residues with the first extracellular domain of the human OX₂ orexin/hypocretin receptor eliciting the development of autoantibodies. Here, we analyzed, whether H1N1pdm09 infection or Pandemrix vaccination contributed to the development of autoantibodies to the orexin precursor protein or the OX₁ or OX₂ receptors. The analysis was based on the presence or absence of autoantibody responses against analyzed proteins. Entire OX₁ and OX₂ receptors or just their extracellular N-termini were transiently expressed in HuH7 cells to determine specific antibody responses in human sera. Based on our immunofluorescence analysis, none of the 56 Pandemrix-vaccinated narcoleptic patients, 28 patients who suffered from a laboratory-confirmed H1N1pdm09 infection or 19 Pandemrix-vaccinated controls showed specific autoantibody responses to prepro-orexin, orexin receptors or the isolated extracellular N-termini of orexin receptors. We also did not find any evidence for cell-mediated immunity against the N-terminal epitopes of OX₂. Our findings do not support the hypothesis that the surface-exposed region of the influenza nucleoprotein A would elicit the development of an immune response against orexin receptors.

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No evidence of humoral immunity against human OX₁ or OX₂ orexin receptors.

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No cross-reactive antibodies between influenza virus NP and orexin receptors.

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No evidence for cell-mediated immunity against the N-terminal epitopes of OX₂.