SARS-CoV-2 infections elicit higher levels of original antigenic sin antibodies compared to SARS-CoV-2 mRNA vaccinations (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines elicit higher levels of antibodies compared to natural SARS-CoV-2 infections in most individuals; however, the specificities of antibodies elicited by vaccination versus infection remain incompletely understood. Here, we characterized the magnitude and specificity of SARS-CoV-2 spike-reactive antibodies from 10 acutely infected health care workers and 23 participants who received mRNA-based SARS-CoV-2 vaccines. We found that infection and primary mRNA vaccination elicited S1 and S2-reactive antibodies, while secondary vaccination boosted mostly S1 antibodies. Using magnetic bead-based absorption assays, we found that SARS-CoV-2 infections elicited a large proportion of original antigenic sin-like antibodies that bound efficiently to common seasonal human coronaviruses but poorly to SARS-CoV-2. In converse, vaccination only modestly boosted antibodies reactive to common seasonal human coronaviruses and these antibodies bound efficiently to SARS-CoV-2. Our data indicate that SARS-CoV-2 mRNA vaccinations elicit fundamentally different antibody responses compared to SARS-CoV-2 infections. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/21264363v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@3e4acdorg.highwire.dtl.DTLVardef@1a0e83eorg.highwire.dtl.DTLVardef@ef4468org.highwire.dtl.DTLVardef@7441c4_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LISARS-CoV-2 mRNA vaccines elicit higher levels of antibodies compared to SARS-CoV-2 infections C_LIO_LIThe first dose of an mRNA vaccine generates both S1 and S2 responses while the second dose boosts primarily S1-specific antibodies C_LIO_LISARS-CoV-2 infections, but not mRNA vaccinations, elicit high levels of antibodies that bind strongly to seasonal coronaviruses but weakly to SARS-CoV-2 C_LI

Sero-monitoring of health care workers reveals complex relationships between common coronavirus antibodies and SARS-CoV-2 severity (preprint)

Recent common coronavirus (CCV) infections are associated with reduced COVID-19 severity upon SARS-CoV-2 infection, however the immunological mechanisms involved are unknown. We completed serological assays using samples collected from health care workers to identify antibody types associated with SARS-CoV-2 protection and COVID-19 severity. Rare SARS-CoV-2 cross-reactive antibodies elicited by past CCV infections were not associated with protection; however, the duration of symptoms following SARS-CoV-2 infections was significantly reduced in individuals with higher common betacoronavirus ({beta}CoV) antibody titers. Since antibody titers decline over time after CCV infections, individuals in our cohort with higher {beta}CoV antibody titers were more likely recently infected with common {beta}CoVs compared to individuals with lower antibody titers. Therefore, our data suggest that recent {beta}CoV infections potentially limit the severity of SARS-CoV-2 infections through mechanisms that do not involve cross-reactive antibodies. Our data are consistent with the emerging hypothesis that cellular immune responses elicited by recent common {beta}CoV infections transiently reduce disease severity following SARS-CoV-2 infections.

Seasonal human coronavirus antibodies are boosted upon SARS-CoV-2 infection but not associated with protection (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread within the human population. Although SARS-CoV-2 is a novel coronavirus, most humans had been previously exposed to other antigenically distinct common seasonal human coronaviruses (hCoVs) before the COVID-19 pandemic. Here, we quantified levels of SARS-CoV-2-reactive antibodies and hCoV-reactive antibodies in serum samples collected from 204 humans before the COVID-19 pandemic. We then quantified pre-pandemic antibody levels in serum from a separate cohort of 252 individuals who became PCR-confirmed infected with SARS-CoV-2. Finally, we longitudinally measured hCoV and SARS-CoV-2 antibodies in the serum of hospitalized COVID-19 patients. Our studies indicate that most individuals possessed hCoV-reactive antibodies before the COVID-19 pandemic. We determined that [~]23% of these individuals possessed non-neutralizing antibodies that cross-reacted with SARS-CoV-2 spike and nucleocapsid proteins. These antibodies were not associated with protection against SARS-CoV-2 infections or hospitalizations, but paradoxically these hCoV cross-reactive antibodies were boosted upon SARS-CoV-2 infection.

Transplacental Transfer of SARS-CoV-2 Antibodies (preprint)

We measured SARS-CoV-2 antibody levels in serum samples from 1,471 mother/newborn dyads and found efficient transplacental transfer of SARS-CoV-2 IgG antibodies in 72 of 83 seropositive pregnant women. Transfer ratios >1.0 were observed among women with an asymptomatic SARS-CoV-2 infection as well as those with mild, moderate and severe COVID-19. Our findings demonstrate the potential for maternally-derived antibodies to provide neonatal protection from SARS-CoV-2 infection.

Deep Immune Profiling of MIS-C demonstrates marked but transient immune activation compared to adult and pediatric COVID-19 (preprint)

Pediatric COVID-19 following SARS-CoV-2 infection is associated with fewer hospitalizations and often milder disease than in adults. A subset of children, however, present with Multisystem Inflammatory Syndrome in Children (MIS-C) that can lead to vascular complications and shock, but rarely death. The immune features of MIS-C compared to pediatric COVID-19 or adult disease remain poorly understood. We analyzed peripheral blood immune responses in hospitalized SARS-CoV-2 infected pediatric patients (pediatric COVID-19) and patients with MIS-C. MIS-C patients had patterns of T cell-biased lymphopenia and T cell activation similar to severely ill adults, and all patients with MIS-C had SARS-CoV-2 spike-specific antibodies at admission. A distinct feature of MIS-C patients was robust activation of vascular patrolling CX3CR1+ CD8 T cells that correlated with use of vasoactive medication. Finally, whereas pediatric COVID-19 patients with acute respiratory distress syndrome (ARDS) had sustained immune activation, MIS-C patients displayed clinical improvement over time, concomitant with decreasing immune activation. Thus, non-MIS-C versus MIS-C SARS-CoV-2 associated illnesses are characterized by divergent immune signatures that are temporally distinct and implicate CD8 T cells in clinical presentation and trajectory of MIS-C.

SARS-CoV-2 antibody responses in children with MIS-C and mild and severe COVID-19 (preprint)

SARS-CoV-2 antibody responses in children remain poorly characterized. Here, we show that pediatric patients with multisystem inflammatory syndrome in children (MIS-C) possess higher SARS-CoV-2 spike IgG titers compared to those with severe coronavirus disease 2019 (COVID-19), likely reflecting a longer time since onset of infection in MIS-C patients.

SARS-CoV-2 Seroprevalence Among Parturient Women (preprint)

Limited data are available for pregnant women affected by SARS-CoV-2. Serological tests are critically important to determine exposure and immunity to SARS-CoV-2 within both individuals and populations. We completed SARS-CoV-2 serological testing of 1,293 parturient women at two centers in Philadelphia from April 4 to June 3, 2020. We tested 834 pre-pandemic samples collected in 2019 and 15 samples from COVID-19 recovered donors to validate our assay, which has a [~]1% false positive rate. We found 80/1,293 (6.2%) of parturient women possessed IgG and/or IgM SARS-CoV-2-specific antibodies. We found race/ethnicity differences in seroprevalence rates, with higher rates in Black/non-Hispanic and Hispanic/Latino women. Of the 72 seropositive women who also received nasopharyngeal polymerase chain reaction testing during pregnancy, 46 (64%) were positive. Continued serologic surveillance among pregnant women may inform perinatal clinical practices and can potentially be used to estimate seroprevalence within the community. One Sentence SummarySix percent of pregnant women delivering from April 4 to June 3, 2020 had serological evidence of exposure to SARS-CoV-2 with notable race/ethnicity differences in seroprevalence rates.

Deep immune profiling of COVID-19 patients reveals patient heterogeneity and distinct immunotypes with implications for therapeutic interventions (preprint)

COVID-19 has become a global pandemic. Immune dysregulation has been implicated, but immune responses remain poorly understood. We analyzed 71 COVID-19 patients compared to recovered and healthy subjects using high dimensional cytometry. Integrated analysis of [~]200 immune and >30 clinical features revealed activation of T cell and B cell subsets, but only in some patients. A subgroup of patients had T cell activation characteristic of acute viral infection and plasmablast responses could reach >30% of circulating B cells. However, another subgroup had lymphocyte activation comparable to uninfected subjects. Stable versus dynamic immunological signatures were identified and linked to trajectories of disease severity change. These analyses identified three "immunotypes" associated with poor clinical trajectories versus improving health. These immunotypes may have implications for therapeutics and vaccines.

Immunologic perturbations in severe COVID-19/SARS-CoV-2 infection (preprint)

Although critical illness has been associated with SARS-CoV-2-induced hyperinflammation, the immune correlates of severe COVID-19 remain unclear. Here, we comprehensively analyzed peripheral blood immune perturbations in 42 SARS-CoV-2 infected and recovered individuals. We identified broad changes in neutrophils, NK cells, and monocytes during severe COVID-19, suggesting excessive mobilization of innate lineages. We found marked activation within T and B cells, highly oligoclonal B cell populations, profound plasmablast expansion, and SARS-CoV-2-specific antibodies in many, but not all, severe COVID-19 cases. Despite this heterogeneity, we found selective clustering of severe COVID-19 cases through unbiased analysis of the aggregated immunological phenotypes. Our findings demonstrate broad immune perturbations spanning both innate and adaptive leukocytes that distinguish dysregulated host responses in severe SARS-CoV-2 infection and warrant therapeutic investigation. One Sentence SummaryBroad immune perturbations in severe COVID-19

SARS-CoV-2 Seroprevalence Among Parturient Women (preprint)

SARS-CoV-2 has led to a pandemic of respiratory and multisystem disease, named COVID-19.1 Limited data are available for pregnant women affected by COVID-19.2 Serological tests, particularly those that provide quantitative information, are critically important to determine exposure and immunity to SARS-CoV-2 within both individuals and populations.3 Here, we completed SARS-CoV-2 serological testing of 237 parturient women at two centers in Philadelphia from April 4 to April 15, 2020. Using an assay with a 1.0% false positive rate, we show that 14/237 (5.9%) of parturient women possessed IgG and/or IgM SARS-CoV-2-specific antibodies. We found significant racial differences, with an 11.2% seropositive rate in black women and a 1.5% seropositive rate in women of other races. Seropositive women who received nasopharyngeal (NP) SARS-CoV-2 PCR (polymerase chain reaction) testing were all found to be positive. Continued serologic surveillance among pregnant women may inform perinatal clinical practices and can potentially be used to estimate seroprevalence within the community.Authors Dustin D. Flannery and Sigrid Gouma contributed equally to this work.