Sensitive detection of SARS-CoV-2 seroconversion by flow cytometry reveals the presence of nucleoprotein-reactive antibodies in unexposed individuals

Egia-Mendikute, Leire; Bosch, Alexandre; Prieto-Fernández, Endika; Lee, So Young; Jiménez-Lasheras, Borja; Río, Ana García del; Antoñana-Vildosola, Asier; Bruzzone, Chiara; Bizkarguenaga, Maider; Embade, Nieves; Gil‐Redondo, Rubén; Martínez‐Chantar, María Luz; López‐Hoyos, Marcos; Abrescia, Nicola G. A.; Mato, José M.; Millet, Óscar; Palazón, Asís

doi:10.1038/s42003-021-02011-6

Cited by 18 publications

(13 citation statements)

References 34 publications

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“… 30 Further, concerns have been raised about the specificity of the use of nucleoprotein for serological assays due to homology with nucleoproteins of other coronaviruses. 32 This is particularly important in a low‐incidence population such as in the present study. Three participants were not tested by pharyngeal RT‐PCR (one by an antigen test and two at private test centers), so exact details about analysis methods are lacking.…”

Section: Discussionmentioning

confidence: 80%

A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection during pregnancy evaluating SARS‐CoV‐2 antibodies in maternal and umbilical cord blood and SARS‐CoV‐2 in vaginal swabs

Milbak

Holten

Axelsson

et al. 2021

Acta Obstet Gynecol Scand

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Introduction Evidence about the consequences of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection in pregnancy is rapidly increasing; however, data on antibody response and risk of transmission during pregnancy and delivery are still limited. The aim of this study was to evaluate if SARS‐CoV‐2 is detectable in vaginal swabs and whether antibodies against SARS‐CoV‐2 are present in maternal and umbilical cord blood of pregnant women with confirmed SARS‐CoV‐2. Material and methods A single‐unit prospective cohort study in Denmark including pregnant women with SARS‐CoV‐2 infection confirmed by a pharyngeal swab between August 20, 2020, and March 1, 2021, who gave birth during the same period. All patients admitted to the maternity ward and antepartum clinic were screened for SARS‐CoV‐2 infection. A maternal blood sample and vaginal swabs were collected at inclusion. If included antepartum, these samples were repeated intrapartum when an umbilical cord blood sample was also collected. Swabs were analyzed for SARS‐CoV‐2 and blood samples were analyzed for SARS‐CoV‐2 total antibodies. Placental and neonatal swabs as well as placental histopathological examinations were performed on clinical indications. Results We included 28 women, of whom four had serious maternal or fetal outcomes including one case of neonatal death. Within the first 8 days after confirmed SARS‐CoV‐2 infection, SARS‐CoV‐2 was detectable in two vaginal swabs (2/28) and SARS‐CoV‐2 antibodies were detected in 1 of 13 women. From 16 days after confirmed infection, antibodies were observed in 19 of 21 of women. Antibodies in cord blood were not detected during the first 16 days after confirmed infection ( n = 7). However, from 26 days, antibodies were present in 16 of 17 cord blood samples of seropositive mothers. Placental examination in two cases of severe fetal outcomes preceded by reduced fetal movements revealed SARS‐CoV‐2 in swabs and severe histopathological abnormalities. Conclusions SARS‐CoV‐2 was detected in only 2 of 28 vaginal swabs within 8 days after confirmed infection in pregnant women. Our data suggest that maternal seroconversion occurs between days 8 and 16, whereas antibodies in cord blood of seropositive mothers were present in the majority from 26 days after confirmed infection. Additional data are needed regarding timing of seroconversion for the mother and appearance of antibodies in cord blood.

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Section: Discussionmentioning

confidence: 80%

A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection during pregnancy evaluating SARS‐CoV‐2 antibodies in maternal and umbilical cord blood and SARS‐CoV‐2 in vaginal swabs

Milbak

Holten

Axelsson

et al. 2021

Acta Obstet Gynecol Scand

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“…Higher epitope density likely allows for monogamous multivalent binding of low affinity antibodies. Other immunoassays to detect specific anti-Spike antibodies by flow cytometry have been developed and either do not show IgM detection ( 20 , 21 ) or they do efficiently detect IgM on beads where the antigen has been adsorbed ( 22 – 24 ) or on the surface of HEK-293T cells where the antigen is overexpressed ( 25 – 28 ). In these two approaches epitope density is higher compared to the Jurkat-Spike cells of the JFCI, in line with our argument.…”

Section: Discussionmentioning

confidence: 99%

Vaccine Type-, Age- and Past Infection-Dependence of the Humoral Response to SARS-CoV-2 Spike S Protein

Romero-Pinedo¹,

Quesada²,

Horndler

et al. 2022

Front. Immunol.

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The emergence of COVID-19 has led to a worldwide challenge for the rapid development of vaccines. Several types of safe and effective vaccines have been available in a time frame never seen before. Now that several hundred million people have been vaccinated there is an opportunity to compare vaccines in terms of protection and immune response. Here, we have applied a highly sensitive multiplexed flow cytometry method to measure simultaneously IgM, IgG1 and IgA anti-spike protein antibodies generated in response to three vaccines: ChAdOx1 (Oxford-AstraZeneca), mRNA-1273 (Moderna), and BNT162b2 (Pfizer-BioNTech). We have found that mRNA vaccines (mRNA-1273 and BNT162b2) induce a stronger humoral response, both after the first and the second dose, than the adenovirus-based ChAdOx1 vaccine. We also found that, in the elderly, antibody titers negatively correlate with the age of the donor but, also, that antibody titers remain stable for at least 6 months after complete vaccination. Finally, we found that one dose of BNT162b2 is sufficient to induce the highest antibody titers in seropositive pre-vaccination donors. We hope these data will help to guide future decisions on vaccination strategies.

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“…A common feature of COVID-19 patients is moderate to severe hypoxia [12, 13, 14, 15]. Disease severity correlates with the level of naturally occurring anti-SARS-CoV-2 antibodies in serum [16], and patients with severe disease are characterized by low oxygen saturation that often results in the need of oxygen supplementation [17]. Currently, the impact of hypoxia on SARS-CoV-2 infectivity and COVID-19 pathogenesis is unclear, but there are emerging indications that low oxygen concentrations might prevent infection or disease severity [18, 19].…”

Section: Introductionmentioning

confidence: 99%

Hypoxia reduces cell attachment of SARS-CoV-2 spike protein by modulating the expression of ACE2, neuropilin-1, syndecan-1 and cellular heparan sulfate

Prieto-Fernández

Egia-Mendikute

Vila-Vecilla

et al. 2021

Preprint

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A main clinical parameter of Covid-19 pathophysiology is hypoxia. Here we show that hypoxia decreases the attachment of the receptor binding domain (RBD) and the S1 subunit (S1) of the spike protein to epithelial cells. In Vero E6 cells, hypoxia reduces the protein levels of ACE2, which might in part explain the observed reduction of the infection rate. However, hypoxia also inhibits the binding of the spike to human lung epithelial cells lacking ACE2 expression, indicating that hypoxia modulates the expression of additional binding partners of SARS-CoV-2. We show that hypoxia also decreases the total cell surface levels of heparan sulfate, a known attachment receptor of SARS-CoV-2, by reducing the expression of syndecan-1 and syndecan3, the main proteoglycans containing heparan sulfate. Our study indicates that hypoxia acts to prevent SARS-CoV-2 infection, suggesting that the hypoxia signaling pathway might offer therapeutic opportunities for the treatment of Covid-19.

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Sensitive detection of SARS-CoV-2 seroconversion by flow cytometry reveals the presence of nucleoprotein-reactive antibodies in unexposed individuals

Cited by 18 publications

References 34 publications

A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection during pregnancy evaluating SARS‐CoV‐2 antibodies in maternal and umbilical cord blood and SARS‐CoV‐2 in vaginal swabs

A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection during pregnancy evaluating SARS‐CoV‐2 antibodies in maternal and umbilical cord blood and SARS‐CoV‐2 in vaginal swabs

Vaccine Type-, Age- and Past Infection-Dependence of the Humoral Response to SARS-CoV-2 Spike S Protein

Hypoxia reduces cell attachment of SARS-CoV-2 spike protein by modulating the expression of ACE2, neuropilin-1, syndecan-1 and cellular heparan sulfate

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