Host Predictors of Broadly Cross-Reactive Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants of Concern Differ Between Infection and Vaccination

Utility of nasal swabs for assessing mucosal immune responses towards SARS-CoV-2

SARS-CoV-2 has caused millions of infections worldwide since its emergence in 2019. Understanding how infection and vaccination induce mucosal immune responses and how they fluctuate over time is important, especially since they are key in preventing infection and reducing disease severity. We established a novel methodology for assessing SARS-CoV-2 cytokine and antibody responses at the nasal epithelium by using nasopharyngeal swabs collected longitudinally before and after either SARS-CoV-2 infection or vaccination. We then compared responses between mucosal and systemic compartments. We demonstrate that cytokine and antibody profiles differ between compartments. Nasal cytokines show a wound healing phenotype while plasma cytokines are consistent with pro-inflammatory pathways. We found that nasal IgA and IgG have different kinetics after infection, with IgA peaking first. Although vaccination results in low nasal IgA, IgG induction persists for up to 180 days post-vaccination. This research highlights the importance of studying mucosal responses in addition to systemic responses to respiratory infections. The methods described herein can be used to further mucosal vaccine development by giving us a better understanding of immunity at the nasal epithelium providing a simpler, alternative clinical practice to studying mucosal responses to infection.

Utility of nasal swabs for assessing mucosal immune responses towards SARS-CoV-2

SARS-CoV-2 has caused millions of infections worldwide since its emergence in 2019. Understanding how infection and vaccination induce mucosal immune responses and how they fluctuate over time is important, especially since they are key in preventing infection and reducing disease severity. We established a novel methodology for assessing SARS-CoV-2 cytokine and antibody responses at the nasal epithelium by using nasopharyngeal swabs collected longitudinally before and after either SARS-CoV-2 infection or vaccination. We then compared responses between mucosal and systemic compartments. We demonstrate that cytokine and antibody profiles differ markedly between compartments. Nasal cytokines show a wound healing phenotype while plasma cytokines are consistent with pro-inflammatory pathways. We found that nasal IgA and IgG have different kinetics after infection, with IgA peaking first. Although vaccination results in low nasal IgA, IgG induction persists for up to 180 days post-vaccination. This research highlights the importance of studying mucosal responses in addition to systemic responses to respiratory infections to understand the correlates of disease severity and immune memory. The methods described herein can be used to further mucosal vaccine development by giving us a better understanding of immunity at the nasal epithelium providing a simpler, alternative clinical practice to studying mucosal responses to infection.

Teaser

A nasopharyngeal swab can be used to study the intranasal immune response and yields much more information than a simple viral diagnosis.

Investigating the Current Status of SARS-CoV-2 Antibodies in Hospital Staff

The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 had reported over 676 million cases by March 2023. The main aim of this study is to investigate whether the levels of anti-S and anti-N antibodies could precisely indicate the degree of protection against SARS-CoV-2 and affect the probability or time of contracting COVID-19. In this study, a serosurveillance study was conducted in healthcare workers (HCWs) at a regional hospital in Taiwan to evaluate their antibody levels based on infection and vaccination status. Of 245 HCWs enrolled, all have been vaccinated prior to infection. Of these, 85 participants were infected by SARS-CoV-2, while 160 participants were not infected at the time of blood sample collection. The level of anti-SARS-CoV-2 S antibody was significantly higher in the infected HCWs than in the non-infected participants (p < 0.001). It is worth noting that the mean duration between the administration of the last dose of the vaccine and the occurrence of SARS-CoV-2 infection was 5.61 ± 2.95 months. Our follow-up survey revealed that the non-infected group had significantly higher levels of antibodies compared to the infected group (all p < 0.001). In conclusion, this study suggests that the level of antibodies could serve as a reflection of the protective efficacy against SARS-CoV-2 infection. It has the implication for vaccine decision-making policies in the future.

Severely ill and high-risk COVID-19 patients exhibit increased peripheral circulation of CD62L+ and perforin+ T cells

Introduction

The emergence of SARS-CoV-2, which causes COVID-19, has led to over 400 million reported cases worldwide. COVID-19 disease ranges from asymptomatic infection to severe disease and may be impacted by individual immune differences.

Methods

We used multiparameter flow cytometry to compare CD4+ and CD8+ T cell responses in severe (ICU admitted) and non-severe (admitted to observational unit) hospitalized COVID-19 patients.

Results

We found that patients with severe COVID- 19 had greater frequencies of CD4+ T cells expressing CD62L compared to non-severe patients and greater frequencies of perforin+ CD8+ T cells compared to recovered patients. Furthermore, greater frequencies of CD62L+ CD4+ and CD8+ T cells were seen in severely ill diabetic patients compared to non-severe and non-diabetic patients, and increased CD62L+ CD4+ T cells were also seen in severely ill patients with hypertension.

Discussion

This is the first report to show that CD62L+ T cells and perforin+ T cells are associated with severe COVID-19 illness and are significantly increased in patients with high-risk pre-existing conditions including older age and diabetes. These data provide a potential biological marker for severe COVID-19.

PARIS and SPARTA: Finding the Achilles' Heel of SARS-CoV-2

To understand reinfection rates and correlates of protection for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we established eight different longitudinal cohorts in 2020 under the umbrella of the PARIS (Protection Associated with Rapid Immunity to SARS-CoV-2)/SPARTA (SARS SeroPrevalence And Respiratory Tract Assessment) studies. Here, we describe the PARIS/SPARTA cohorts, the harmonized assays and analysis that are performed across the cohorts, as well as case definitions for SARS-CoV-2 infection and reinfection that have been established by the team of PARIS/SPARTA investigators. IMPORTANCE Determining reinfection rates and correlates of protection against SARS-CoV-2 infection induced by both natural infection and vaccination is of high significance for the prevention and control of coronavirus disease 2019 (COVID-19). Furthermore, understanding reinfections or infection after vaccination and the role immune escape plays in these scenarios will inform the need for updates of the current SARS-CoV-2 vaccines and help update guidelines suitable for the postpandemic world.

Molecular dynamic simulations reveal anti-SARS-CoV-2 activity of mitocurcumin by potentially blocking innate immune evasion proteins NSP3 and NSP16

The coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is affecting human life in an unprecedented manner and has become a global public health emergency. Identification of novel inhibitors of viral infection/replication is the utmost priority to curtail COVID-19 progression. A pre-requisite for such inhibitors is good bioavailability, non-toxicity and serum stability. Computational studies have shown that curcumin can be a candidate inhibitor of certain SARS-CoV-2 proteins; however, poor bio-availability of curcumin limits its possible therapeutic application. To circumvent this limitation, we have used mitocurcumin (MC), a triphenyl phosphonium conjugated curcumin derivative, to study the ability to inhibit SARS-CoV-2 infection using molecular docking and molecular dynamics (MD) simulation. MC is serum stable and several fold more potent as compared to curcumin. Molecular docking studies revealed that MC can bind at active site of SARS-CoV-2 ADP Ribose Phosphatase (NSP3) and SARS-CoV-2 methyltransferase (NSP10-NSP16 complex) with a high binding energy of - 10.3 kcal/mol and - 10.4 kcal/mol, respectively. MD simulation (100 ns) studies revealed that binding of MC to NSP3 and NSP16 resulted in a stable complex. MC interacted with critical residues of NSP3 macro-domain and NSP10-NSP16 complex and occupied their active sites. NSP3 is known to suppress host immune responses whereas NSP10-NSP16 complex is known to prevent immune recognition of viral mRNA. Our study suggests that MC can potentially inhibit the activity of NSP3 and NSP10-NSP16 complex, resulting in compromised viral immune evasion mechanism, and thereby accentuate the innate immune mediated clearance of viral load.

SARS-CoV-2 Antibody Response Is Associated with Age and Body Mass Index in Convalescent Outpatients

COVID-19 has had an unprecedented global impact on human health. Understanding the Ab memory responses to infection is one tool needed to effectively control the pandemic. Among 173 outpatients who had virologically confirmed SARS-CoV-2 infection, we evaluated serum Ab concentrations, microneutralization activity, and enumerated SARS-CoV-2-specific B cells in convalescent human blood specimens. Serum Ab concentrations were variable, allowing for stratification of the cohort into high and low responders. Neither participant sex, the timing of blood sampling following the onset of illness, nor the number of SARS-CoV-2 spike protein-specific B cells correlated with serum Ab concentration. Serum Ab concentration was positively associated with microneutralization activity and participant age, with participants under the age of 30 showing the lowest Ab level. These data suggest that young adult outpatients did not generate as robust Ab memory, compared with older adults. Body mass index was also positively correlated with serum Ab levels. Multivariate analyses showed that participant age and body mass index were independently associated with Ab levels. These findings have direct implications for public health policy and current vaccine efforts. Knowledge gained regarding Ab memory following infection will inform the need for vaccination in those previously infected and allow for a better approximation of population-wide protective immunity.

Booster vaccination strategy: Necessity, Immunization Objectives, Immunization Strategy and Safety

At present, the global COVID-19 epidemic has not been completely controlled, and epidemic prevention and control still face severe challenges. As there is no specific treatment for COVID-19, promoting roll-out vaccinations and building herd immunity are still the most effective and economic measures to control the COVID-19 pandemic. However, the neutralizing antibody level in the recipients decreases with time, and the vaccine's protective efficacy gradually weakens. It is still inconclusive whether it is necessary to carry out booster vaccination to strengthen the immune barrier to infection. In this paper, we combined the existing data on the effectiveness and persistence of COVID-19 vaccines. We found that it is necessary to carry out a booster vaccination strategy. However, not all subjects need to receive one more dose of vaccine six months after the initial immunization. Priority should be given to the high-risk groups, such as the elderly and people with immunodeficiency. A heterologous booster can induce higher immune responses and enhance immune protection than homologous vaccinations. However, more scientific data and clinical studies are needed to verify the safety of heterologous vaccination strategies. This article is protected by copyright. All rights reserved.