ABSTRACT
BackgroundA fraction of COVID-19 patients develops severe disease requiring hospitalization, while the majority, including high-risk individuals, experience mild symptoms. Severe disease has been associated with higher levels of antibodies and inflammatory cytokines, but the association has often resulted from comparison of patients with diverse demographics and comorbidity status. This study examined patients with defined demographic risk factors for severe COVID-19 who developed mild vs. severe COVID-19. MethodsThis study evaluated hospitalized vs. ambulatory COVID-19 patients in the James J. Peters VA Medical Center, Bronx, NY. This cohort presented demographic risk factors for severe COVID-19: median age of 63, >80% male, >85% black and/or Hispanic. Sera were collected four to 243 days after symptom onset and evaluated for binding and functional antibodies as well as 48 cytokines/chemokines. FindingsAmbulatory and hospitalized patients showed no difference in SARS-CoV-2-specific antibody levels and functions. However, a strong correlation between anti-S2 antibody levels and the other antibody parameters was observed in hospitalized but not in ambulatory cases. Cytokine/chemokine levels also revealed differences, with notably higher IL-27 levels in hospitalized patients. Hence, among the older, mostly male patients studied here, SARS-CoV-2-specific antibody levels and functions did not distinguish hospitalized and ambulatory cases but a discordance in S2-specific antibody responses was noted in ambulatory patients, and elevated levels of specific cytokines were maintained in convalescent sera of hospitalized cases. InterpretationThe data indicate that antibodies against the relatively conserved S2 spike subunit and immunoregulatory cytokines such as IL-27 are potential immune determinants of COVID-19. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSPrevious studies demonstrated that high levels of SARS-CoV-2 spike binding antibodies and neutralizing antibodies were associated with COVID-19 disease severity. However, the comparisons were often made without considering demographics and comorbidities. Correlation was similarly shown between severe disease and marked elevation of several plasma cytokines but again, most analyses of cytokine responses to COVID-19 were conducted by comparison of patient cohorts with diverse demographic characteristics and risk factors. Added value of this studyWe evaluated here a comprehensive profile of SARS-CoV-2-specific antibodies (total Ig, isotypes/subtypes, Fab- and Fc-mediated functions) and a panel of 48 cytokines and chemokines in serum samples from a cohort of SARS-CoV-2-infected patients with demographic risk factors for severe COVID-19: 81% were male, 79% were >50 years old (median of 63), and 85% belonged to US minority groups (black and/or Hispanic). Comparison of hospitalized vs. ambulatory patients within this cohort revealed two features that differed between severe vs. mild COVID-19 cases: a discordant Ab response to the S2 subunit of the viral spike protein in the mild cases and an elevated response of specific cytokines and chemokines, notably IL-27, in the severe cases. Implications of all the available evidenceData from the study identified key immunologic markers for severe vs. mild COVID-19 that provide a path forward for investigations of their roles in minimizing or augmenting disease severity.
Subject(s)
Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
Background: Mass vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is on-going in the United States with vaccines approved for emergency use by the FDA. Each vaccine can induce spike-specific antibodies (Abs) with virus-neutralizing activities; however, the Fc-mediated Ab activities have received little attention. Moreover, while plasma/serum Abs are commonly studied, scant information is available about Abs in the respiratory mucosa, the site of SARS-CoV-2 transmission. Methods: Plasma and saliva were collected from mRNA vaccine recipients and convalescent coronavirus disease 2019 (COVID-19) patients. Antigen-specific total Ig and Ig isotypes were measured. In addition to virus neutralization, Fc-mediated activities were investigated, including antibody-dependent cellular phagocytosis (ADCP) and complement deposition. Results: Similar to infection, vaccination stimulated spike-specific Ab responses detected in plasma and saliva, with IgG1 as the dominant isotype. Interestingly, vaccination produced greater IgG2, IgG3, and IgG4 responses and higher ratios of (IgG1+IgG3)/(IgG2+IgG4) than infection. Moreover, while plasma neutralization and ADCP potencies were comparable in vaccinated and convalescent individuals, vaccine-induced plasma Abs elicited stronger complement binding and activation. Conclusion: Compared with natural infection, mRNA vaccines induced a greater array of IgG subtypes against spike in saliva and plasma. The vaccine-induced Abs were also more potent in mediating complement activation.
Subject(s)
Coronavirus Infections , COVID-19 , ConvalescenceABSTRACT
SARS-CoV-2 has infected millions of people and is on a trajectory to kill more than one million globally. Virus entry depends on the receptor-binding domain (RBD) of the spike protein. Although previous studies demonstrated anti-spike and -RBD antibodies as essential for protection and convalescent plasma as a promising therapeutic option, little is known about the immunoglobulin (Ig) isotypes capable of blocking virus entry. Here, we studied spike- and RBD-specific Ig isotypes in plasma/sera from two acutely infected and 29 convalescent individuals. Spike- and RBD-specific IgM, IgG1, and IgA1 antibodies were produced by all or nearly all subjects at varying levels and detected at 7-8 days post-disease onset. IgG2, IgG3, IgG4, and IgA2 were also present but at much lower levels. All samples also displayed neutralizing activity. IgM, IgG, and IgA were capable of mediating neutralization, but neutralization titers correlated better with binding levels of IgM and IgA1 than IgG.
Subject(s)
Acute DiseaseABSTRACT
COVID-19 (coronavirus disease 2019) is a pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome-coronavirus 2) infection affecting millions of persons around the world. There is an urgent unmet need to provide an easy-to-produce, affordable medicine to prevent transmission and provide early treatment for this disease. The nasal cavity and the rhinopharynx are the sites of initial replication of SARS-CoV-2. Therefore, a nasal spray may be a suitable dosage form for this purpose. The main objective of our study was to test the antiviral action of three candidate nasal spray formulations against SARS-CoV-2. We have found that iota-carrageenan in concentrations as low as 6 {micro}g/ mL inhibits SARS-CoV-2 infection in Vero cell cultures. The concentrations found to be active in vitro against SARS-CoV-2 may be easily achieved by the application of nasal sprays already marketed in several countries. Xylitol at a concentration of 5 % m/V has proved to be viricidal on its own and the association with iota-carrageenan may be beneficial, as well.
Subject(s)
COVID-19 , Coronavirus InfectionsABSTRACT
The global COVID-19 pandemic has mobilized efforts to develop vaccines and antibody-based therapeutics, including convalescent plasma therapy, that inhibit viral entry by inducing or transferring neutralizing antibodies (nAbs) against the SARS-CoV-2 spike glycoprotein (CoV2-S). However, rigorous efficacy testing requires extensive screening with live virus under onerous BSL3 conditions which limits high throughput screening of patient and vaccine sera. Myriad BSL-2 compatible surrogate virus neutralization assays (VNAs) have been developed to overcome this barrier. Yet, there is marked variability between VNAs and how their results are presented, making inter-group comparisons difficult. To address these limitations, we developed a standardized VNA using VSVAG-based CoV-2-S pseudotyped particles (CoV2pp) that can be robustly produced at scale and generate accurate neutralizing titers within 18 hours post-infection. Our standardized CoV2pp VNA showed a strong positive correlation with CoV2-S ELISA and live virus neutralizations in confirmed convalescent patient sera. Three independent groups subsequently validated our standardized CoV2pp VNA (n>120). Our data show that absolute (abs) IC50, IC80, and IC90 values can be legitimately compared across diverse cohorts, highlight the substantial but consistent variability in neutralization potency across these cohorts, and support the use of absIC80 as a more meaningful metric for assessing the neutralization potency of vaccine or convalescent sera. Lastly, we used our CoV2pp in a screen to identify ultra-permissive 293T clones that stably express ACE2 or ACE2+TMPRSS2. When used in combination with our CoV2pp, we can now produce CoV2pp sufficient for 150,000 standardized VNA/week. ImportanceVaccines and antibody-based therapeutics like convalescent plasma therapy are premised upon inducing or transferring neutralizing antibodies that inhibit SARS-CoV-2 entry into cells. Virus neutralization assays (VNAs) for measuring neutralizing antibody titers (NATs) is an essential part of determining vaccine or therapeutic efficacy. However, such efficacy testing is limited by the inherent dangers of working with the live virus, which requires specialized high-level biocontainment facilities. We therefore developed a standardized replication-defective pseudotyped particle system that mimics entry of live SARS-CoV-2. This tool allows for the safe and efficient measurement of NATs, determination of other forms of entry inhibition, and thorough investigation of virus entry mechanisms. Four independent labs across the globe validated our standardized VNA using diverse cohorts. We argue that a standardized and scalable assay is necessary for meaningful comparisons of the myriad of vaccines and antibody-based therapeutics becoming available. Our data provide generalizable metrics for assessing their efficacy.