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1.
Preprint in English | medRxiv | ID: ppmedrxiv-22274196

ABSTRACT

The detailed mechanisms of COVID-19 infection pathology remain poorly understood. To improve our understanding of SARS-CoV-2 pathology, we performed a multi-omics analysis of an immunologically naive SARS-CoV-2 clinical cohort from the plasma of uninfected controls, mild, and severe infections. A comparison of healthy controls and patient samples showed activation of neutrophil degranulation pathways and formation of neutrophil extracellular trap (NET) complexes that were activated in a subset of the mild infections and more prevalent in severe infections (containing multiple NET proteins in individual patient samples). As a potential mechanism to suppress NET formation, multiple redox enzymes were elevated in the mild and severe symptom population. Analysis of metabolites from the same cohort showed a 24- and 60-fold elevation in plasma L-cystine, the oxidized form of cysteine, which is a substrate of the powerful antioxidant glutathione, in mild and severe patients, respectively. Unique to patients with mild infections, the carnosine dipeptidase modifying enzyme (CNDP1) was up-regulated. The strong protein and metabolite oxidation signatures suggest multiple compensatory pathways working to suppress oxidation and NET formation in SARS-CoV-2 infections.

2.
Preprint in English | medRxiv | ID: ppmedrxiv-22272766

ABSTRACT

BackgroundLittle is known about the population prevalence of antibodies against emerging immune escape variants of SARS-CoV-2. MethodsA population-based prevalence study was conducted in Yokohama City, the most populous municipality of Japan. Quantitative measurements of immunoglobulin G against SARS-CoV-2 spike protein (SP-IgG) and qualitative measurements of neutralization antibodies against the Omicron BA.1 and BA.2 variants were performed. ResultsOf 6,000 randomly selected residents aged 20-74, 1,277 participated in the study during a period from January 30 to February 28, 2022. Of them, 3% had prior diagnosis of COVID-19, 96% received at least two-doses of SARS-CoV-2 vaccines, and 94% were positive for SP-IgG. The positive rates of neutralizing antibodies were 28% to Omicron BA.1 and BA.2 variants in a random sample of 10% of participants (n=123) and 100% to BA.1 and BA.2 among participants who received the third vaccination at least 7 days before (n=66). ConclusionsIn this population-based prevalence study in Japan, most had SP-IgG antibodies but the overall neutralizing antibody positive rate was 28% against the Omicron BA.1 and BA.2 variants. The population-level insufficient humoral immunity against the Omicron variants may explain the outbreak of COVID-19 during this period in Japan.

3.
Preprint in English | medRxiv | ID: ppmedrxiv-21265693

ABSTRACT

To evaluate vaccine-induced humoral and cell-mediated immunity at 6 months post BNT162b2 vaccination, immunoglobulin G against SARS-CoV-2 spike protein (SP IgG), 50% neutralizing antibody (NT50), and spot-forming cell (SFC) counts were evaluated by interferon-{gamma} releasing ELISpot assay of 98 healthy subjects (median age, 43 years). The geometric mean titers of SP IgG and NT50 decreased from 95.2 (95% confidence interval (CI) 79.8-113.4) to 5.7 (95% CI 4.9-6.7) and from 680.4 (588.0-787.2) to 130.4 (95% CI 104.2-163.1), respectively, at 3 weeks and 6 months after the vaccination. SP IgG titer was negatively correlated with age and alcohol consumption. Spot-forming cell counts at 6 months did not correlate with age, gender, and other parameters of the patients. SP IgG, NT50, and SFC titers were elevated in the breakthrough infected subjects. Although the levels of vaccine-induced antibodies dramatically declined at 6 months after vaccination, a certain degree of cellular immunity was observed irrespective of the age.

4.
Preprint in English | medRxiv | ID: ppmedrxiv-21264013

ABSTRACT

SARS-CoV-2 infection elicits varying degrees of protective immunity conferred by neutralizing antibodies (nAbs). Here we report the persistence of nAb responses over 12 months after infection despite its decreasing trend noticed from 6 months. The study included sera from 358 individuals who had been infected with SARS-CoV-2 between January and May 2020. Samples were collected at 6 and 12 months after onset. The titers of IgG to the viral nucleocapsid protein (NP) and receptor-binding domain of the spike protein (RBD) were measured by CLEIA. The nAb titer was determined using lentivirus-based pseudovirus or authentic virus. Antibody titers of NP-IgG, RBD-IgG, and nAbs were higher in severe and moderate cases than in mild cases at 12 months after onset. While the nAb levels were likely to confer adequate protection against wild-type viral infection, the neutralization activity to recently circulating variants in some of the mild cases ([~]30%) was undermined, implying the susceptibility of reinfection to the variants of concerns (VOCs). COVID-19 convalescent individuals have robust humoral immunity even at 12 months after infection albeit that the medical history and background of patients could affect the function and dynamics of antibody response to the VOCs.

5.
Preprint in English | medRxiv | ID: ppmedrxiv-21264014

ABSTRACT

The rise of mutant strains of SARS-CoV-2 poses an additional problem to the existing pandemic of COVID-19. There are rising concerns about the Mu variant which can escape humoral immunity acquired from infections from previous strains or vaccines. We examined the neutralizing efficacy of the BNT162b2 mRNA vaccine against the Mu variant and report that the vaccine has 76% neutralizing effectiveness against the Mu compared to 96% with the original strain. We also show that Mu, similar to the Delta variant, causes cell-to-cell fusion which can be an additional factor for the variant to escape vaccine-mediated humoral immunity. Despite the rise in vaccine escape strains, the vaccine still possesses adequate ability to neutralize majority of the mutants.

6.
Preprint in English | medRxiv | ID: ppmedrxiv-21263927

ABSTRACT

BackgroundLevels of 50% neutralizing titer (NT50) reflect a vaccine-induced humoral immunity after the vaccination against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Measurements of NT50 are difficult to implement in large quantities. A high-throughput laboratory test is expected for determining the level of herd immunity against SARS-CoV-2. MethodsWe analyzed samples from 168 Japanese healthcare workers who had completed two doses of the BNT162b2 vaccine. We analyzed immunoglobulin G (IgG) index values against spike protein (SP) using automated chemiluminescent enzyme immunoassay system AIA-CL and analyzed the background factors affecting antibody titer. SP IgG index was compared with 50% neutralization titers. ResultsThe median SP IgG index values of the subjects (mean age = 43 years; 75% female) were 0.1, 1.35, 60.80, and 97.35 before and at 2, 4, and 6 weeks after the first dose, respectively. At 4 and 6 weeks after the first dose, SP IgG titers were found to have positive correlation with NT50 titer (r=0.7535 in 4 weeks; r=0.4376 in 6 weeks). Proportions of the SP IgG index values against the Alpha, Beta, Gamma, and Delta variants compared with the original strain were 2.029, 0.544, 1.017, and 0.6096 respectively. Older age was associated with lower SP IgG titer index 6 weeks after the first dose. ConclusionsSP IgG index values were raised at 3 weeks after two doses of BNT162b2 vaccination and have positive correlation with NT50. SP IgG index values were lower in the older individuals and against Beta and Delta strain.

7.
Preprint in English | medRxiv | ID: ppmedrxiv-21256788

ABSTRACT

The uncontrolled spread of the COVID-19 pandemic has led to the emergence of different SARS-CoV-2 variants across the globe. The ongoing global vaccination strategy to curtail the COVID-19 juggernaut, is threatened by the rapidly spreading Variants of Concern (VOC) and other regional mutants, which are less responsive to neutralization by infection or vaccine derived antibodies. We have previously developed the hiVNT system which detects SARS-CoV-2 neutralizing antibodies in sera in less than three hours. In this study, we modify the hiVNT for rapid qualitative screening of neutralizing antibodies (nAb) to multiple variants of concern (VOC) of SARS-CoV-2, and assess the neutralizing efficacy of the BNT162b2 mRNA vaccine on seven epidemiologically relevant SARS-CoV-2 variants. Here we show that the BNT162b2 mRNA vaccine can activate humoral immunity against the major SARS-CoV-2 mutants that are currently in circulation. Albeit a small sample size, we observed that one dose of vaccine was sufficient to elicit a protective humoral response in previously infected people. Using a panel of seven SARS-CoV-2 variants and a single prototype virus, our modified hiVNT would be useful for large-scale community wide testing to detect protective immunity that may confer vaccine/immune passport in the ongoing COVID-19 pandemic.

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