Evidence that TMPRSS2 Activates the Severe Acute Respiratory Syndrome Coronavirus Spike Protein for Membrane Fusion and Reduces Viral Control by the Humoral Immune Response

AbstractIn addition to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), humans are also susceptible to six other coronaviruses, for which consecutive exposures to antigenically related and divergent seasonal coronaviruses are frequent. Despite the prevalence of COVID-19 pandemic and ongoing research, the nature of the antibody response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Here we longitudinally profile the early humoral immune response against SARS-CoV-2 in hospitalized coronavirus disease 2019 (COVID-19) patients and quantify levels of pre-existing immunity to OC43, HKU1 and 229E seasonal coronaviruses, and find a strong back-boosting effect to conserved but not variable regions of OC43 and HKU1 betacoronaviruses spike protein. However, such antibody memory boost to human coronaviruses negatively correlates with the induction of IgG and IgM against SARS-CoV-2 spike and nucleocapsid protein. Our findings thus provide evidence of immunological imprinting by previous seasonal coronavirus infections that can potentially modulate the antibody profile to SARS-CoV-2 infection.

Download Full-text

SARS-CoV-2 RNA and antibodies in tear fluid

BMJ Open Ophthalmology ◽

10.1136/bmjophth-2021-000733 ◽

2021 ◽

Vol 6 (1) ◽

pp. e000733

Author(s):

Astrid Muyldermans ◽

Maria Bjerke ◽

Thomas Demuyser ◽

Deborah De Geyter ◽

Ingrid Wybo ◽

...

Keyword(s):

Immune Response ◽

Humoral Immune Response ◽

Spike Protein ◽

Tear Fluid ◽

Local Response ◽

Schirmer Test ◽

Humoral Immune ◽

Non Invasive ◽

Reverse Transcription Pcr ◽

Ocular Symptoms

Background/aimsSARS-CoV-2 is highly contagious. More evidence concerning extrapulmonary transmission routes such as the eyes is urgently needed. Although the humoral immune response is important in the viral containment, the local response in tears has not yet been studied. The aim of our study was twofold: to assess the prevalence of both SARS-CoV-2 RNA and antibodies in tear fluid.MethodsIn a first series, nasopharyngeal sampling and tear sampling by Schirmer test strips were performed in 26 acutely ill patients with COVID-19 to assess the presence of SARS-CoV-2 RNA by reverse transcription PCR. In a second series, IgG and IgA responses to SARS-CoV-2 spike protein in serum and tear fluid of convalescent individuals (n=22) were compared with control individuals (n=15) by ELISA.ResultsSARS-CoV-2 RNA was detected in tears of 7/26 (26.9%) patients with COVID-19. None of them had ocular symptoms. Convalescent individuals displayed a significant higher ratio of IgG (p<0.0001) and IgA (p=0.0068) in tears compared with control individuals. A sensitivity of 77.3% and specificity of 93.3% was observed for IgG, and 59.1% and 100% for IgA.ConclusionsOur results demonstrate the presence of SARS-CoV-2 RNA and a local IgG and IgA immune response in tear fluid. These data confirm the possibility of SARS-CoV-2 transmission through tear fluid and the importance of the eye as a first defence against SARS-CoV-2, indicating the potential of tears as a non-invasive surrogate for serum in monitoring the host immune response.

Download Full-text

Two‐Year Prospective Study of the Humoral Immune Response of Patients with Severe Acute Respiratory Syndrome

The Journal of Infectious Diseases ◽

10.1086/500469 ◽

2006 ◽

Vol 193 (6) ◽

pp. 792-795 ◽

Cited By ~ 133

Author(s):

Wei Liu ◽

Arnaud Fontanet ◽

Pan‐He Zhang ◽

Lin Zhan ◽

Zhong‐Tao Xin ◽

...

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Prospective Study ◽

Humoral Immune Response ◽

Humoral Immune

Download Full-text

Crucial Mutations of Spike Protein on SARS-CoV-2 Evolved to Variant Strains Escaping Neutralization of Convalescent Plasmas and RBD-Specific Monoclonal Antibodies

Frontiers in Immunology ◽

10.3389/fimmu.2021.693775 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chengchao Ding ◽

Jun He ◽

Xiangyu Zhang ◽

Chengcheng Jiang ◽

Yong Sun ◽

...

Keyword(s):

Immune Response ◽

Monoclonal Antibodies ◽

Humoral Immune Response ◽

Immune Escape ◽

Spike Protein ◽

Single Amino Acid ◽

Humoral Immune ◽

Cross Neutralization ◽

Altered Sensitivity ◽

Single Amino Acid Mutation

Small number of SARS-CoV-2 epidemic lineages did not efficiently exhibit a neutralization profile, while single amino acid mutation in the spike protein has not been confirmed in altering viral antigenicity resulting in immune escape. To identify crucial mutations in spike protein that escape humoral immune response, we evaluated the cross-neutralization of convalescent plasmas and RBD-specific monoclonal antibodies (mAbs) against various spike protein-based pseudoviruses. Three of 24 SARS-CoV-2 pseudoviruses containing different mutations in spike protein, including D614G, A475V, and E484Q, consistently showed an altered sensitivity to neutralization by convalescent plasmas. A475V and E484Q mutants are highly resistant to neutralization by mAb B38 and 2-4, suggesting that some crucial mutations in spike protein might evolve SARS-CoV-2 variants capable of escaping humoral immune response.

Download Full-text

Sensitivity of two SARS-CoV-2 variants with spike protein mutations to neutralising antibodies

Virus Genes ◽

10.1007/s11262-021-01871-8 ◽

2021 ◽

Author(s):

Katharina Müller ◽

Philipp Girl ◽

Andreas Giebl ◽

Stefanie Gruetzner ◽

Markus Antwerpen ◽

...

Keyword(s):

Immune Response ◽

Humoral Immune Response ◽

Point Of View ◽

Spike Protein ◽

Wild Type ◽

Serum Samples ◽

Antibody Treatment ◽

Neutralising Antibodies ◽

Humoral Immune ◽

Protein Mutations

AbstractSARS-CoV-2 infections elicit a humoral immune response capable of neutralising the virus. However, multiple variants have emerged with mutations in the spike protein amongst others, the key target of neutralising antibodies. We evaluated the neutralising efficacy of 89 serum samples from patients, infected with SARS-CoV-2 in the beginning of 2020, against two virus variants isolated from acutely infected patients and harbouring spike protein mutations. One isolate was assigned to lineage B.1.351 (MUC-IMB-B.1.351) whilst the other (MUC-484) was isolated from an immunocompromised patient, sharing some but not all mutations with B.1.351 and representing a transitional variant. Both variants showed a significant reduction in neutralisation sensitivity compared to wild-type SARS-CoV-2 with MUC-IMB-B.1.351 being almost completely resistant to neutralisation. The observed reduction in neutralising activity of wild-type-specific antibodies against both variants suggests that individual mutations in the spike protein are sufficient to confer a potent escape from the humoral immune response. In addition, the effect of escape mutations seems to accumulate, so that more heavily mutated variants show a greater loss of sensitivity to neutralisation up to complete insensitivity as observed for MUC-IMB-B.1.351. From a clinical point of view, this might affect the efficacy of (monoclonal) antibody treatment of patients with prolonged infections as well as patients infected with variants other than the donor. At the same, this could also negatively influence the efficacy of current vaccines (as they are based on wild-type spike protein) emphasising the need to thoroughly surveil the emergence and distribution of variants and adapt vaccines and therapeutics accordingly.

Download Full-text

MERS-CoV Spike Protein Vaccine and Inactivated Influenza Vaccine Formulated with Single Strand RNA Adjuvant Induce T-Cell Activation through Intranasal Immunization in Mice

Pharmaceutics ◽

10.3390/pharmaceutics12050441 ◽

2020 ◽

Vol 12 (5) ◽

pp. 441

Author(s):

Hye-Jung Kim ◽

Hye Won Kwak ◽

Kyung Won Kang ◽

Yoo-Jin Bang ◽

Yu-Sun Lee ◽

...

Keyword(s):

Immune Response ◽

T Cell ◽

Influenza Vaccine ◽

T Cell Activation ◽

Humoral Immune Response ◽

Cell Activation ◽

Spike Protein ◽

Intranasal Immunization ◽

Humoral Immune ◽

Inoculation Route

The effectiveness of vaccines is enhanced by adding adjuvants. Furthermore, the selection of an inoculation route depends on the type of adjuvant used and is important for achieving optimum vaccine efficacy. We investigated the immunological differences between two types of vaccines—spike protein from the Middle East respiratory syndrome virus and inactivated influenza virus vaccine, in combination with a single-stranded RNA adjuvant—administered through various routes (intramuscular, intradermal, and intranasal) to BALB/c mice. Intramuscular immunization with the RNA adjuvant-formulated spike protein elicited the highest humoral immune response, characterized by IgG1 and neutralizing antibody production. Although intranasal immunization did not elicit a humoral response, it showed extensive T-cell activation through large-scale induction of interferon-γ- and interleukin-2-secreting cells, as well as CD4+ T-cell activation in mouse splenocytes. Moreover, only intranasal immunization induced IgA production. When immunized with the inactivated influenza vaccine, administration of the RNA adjuvant via all routes led to protection after viral challenge, regardless of the presence of a vaccine-specific antibody. Therefore, the inoculation route should depend on the type of immune response needed; i.e., the intramuscular route is suitable for eliciting a humoral immune response, whereas the intranasal route is useful for T-cell activation and IgA induction.

Download Full-text

Humoral and cell-mediated response in colostrum after exposure to severe acute respiratory syndrome coronavirus 2

10.1101/2021.01.03.20248715 ◽

2021 ◽

Author(s):

Vignesh Narayanaswamy ◽

Brian Pentecost ◽

Dominique Alfandari ◽

Emily Chin ◽

Kathleen Minor ◽

...

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Inflammatory Markers ◽

Large Scale ◽

Spike Protein ◽

Receptor Binding Domain ◽

New Mothers ◽

Sandwich Assay ◽

Humoral Immune ◽

Liquid Samples

AbstractBackgroundColostrum provides an immune sharing between a mother and her infant. The transfer in colostrum of antibodies against SARS-CoV-2 and the elicited cytokines may provide crucial protection to the infant. There is limited literature on the immune response to SARS-CoV-2 present in colostrum.ObjectiveTo evaluate the presence of antibodies specific to SARS-CoV-2 and the associated cytokines in colostrum from women who tested positive for the virus.Study DesignBetween March and September 2020 we obtained bilateral colostrum samples collected on spot cards within 48 hours of delivery from 15 new mothers who had previously tested positive for SARS-CoV-2. Five of these 15 COVID-19 positive women also provided bilateral liquid colostrum within 1-2 days of providing the spot card samples. Archived bilateral colostrum samples collected from 8 women during 2011-2013 were used as pre-COVID-19 controls. All samples were tested for reactivity to the Receptor Binding Domain (RBD) of the SARS-CoV-2 spike protein using an ELISA that measures SARS-CoV-2 RBD-specific IgA, IgG, and IgM, and for concentrations of 10 inflammatory cytokines (IFNγ, TNFα, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13) using a multiplex electrochemiluminescent sandwich assay.ResultsBilateral colostrum samples from 73%, 73% and 33% of the 15 COVID-19 mothers exhibited IgA, IgG, and IgM reactivity to RBD respectively. Colostrum samples from two of the 8 pre-pandemic controls showed IgA and IgG reactivity to RBD. Additionally, COVID-19 mothers had significantly higher levels of 9 of the 10 inflammatory markers (all except IFNγ) as compared to the pre-COVID-19 controls. Comparable results were obtained with both the spot card-eluates and liquid samples.ConclusionsA strong humoral immune response is present in the colostrum of women who were infected with SARS-CoV-2 before delivering. High levels of 9 inflammatory markers were also present in the colostrum. The evolution and duration of the antibody response, as well as dynamics of the cytokine response, remain to be determined. Our results also indicate that future large-scale studies can be conducted with milk easily collected on paper spot cards.

Download Full-text

Humoral immunological kinetics of severe acute respiratory syndrome coronavirus 2 infection and diagnostic performance of serological assays for coronavirus disease 2019: an analysis of global reports

International Health ◽

10.1093/inthealth/ihab005 ◽

2021 ◽

Author(s):

Anthony Uchenna Emeribe ◽

Idris Nasir Abdullahi ◽

Halima Ali Shuwa ◽

Leonard Uzairue ◽

Sanusi Musa ◽

...

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Humoral Immune Response ◽

Scale Up ◽

Laboratory Diagnosis ◽

Performance Characteristics ◽

Antibody Detection ◽

Original Research ◽

Humoral Immune ◽

Kinetics Of

Abstract As the coronavirus disease 2019 (COVID-19) pandemic continues to rise and second waves are reported in some countries, serological test kits and strips are being considered to scale up an adequate laboratory response. This study provides an update on the kinetics of humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and performance characteristics of serological protocols (lateral flow assay [LFA], chemiluminescence immunoassay [CLIA] and ELISA) used for evaluations of recent and past SARS-CoV-2 infection. A thorough and comprehensive review of suitable and eligible full-text articles was performed on PubMed, Scopus, Web of Science, Wordometer and medRxiv from 10 January to 16 July 2020. These articles were searched using the Medical Subject Headings terms ‘COVID-19’, ‘Serological assay’, ‘Laboratory Diagnosis’, ‘Performance characteristics’, ‘POCT’, ‘LFA’, ‘CLIA’, ‘ELISA’ and ‘SARS-CoV-2’. Data from original research articles on SARS-CoV-2 antibody detection ≥second day postinfection were included in this study. In total, there were 7938 published articles on humoral immune response and laboratory diagnosis of COVID-19. Of these, 74 were included in this study. The detection, peak and decline period of blood anti-SARS-CoV-2 IgM, IgG and total antibodies for point-of-care testing (POCT), ELISA and CLIA vary widely. The most promising of these assays for POCT detected anti-SARS-CoV-2 at day 3 postinfection and peaked on the 15th day; ELISA products detected anti-SARS-CoV-2 IgM and IgG at days 2 and 6 then peaked on the eighth day; and the most promising CLIA product detected anti-SARS-CoV-2 at day 1 and peaked on the 30th day. The most promising LFA, ELISA and CLIA that had the best performance characteristics were those targeting total SARS-CoV-2 antibodies followed by those targeting anti-SARS-CoV-2 IgG then IgM. Essentially, the CLIA-based SARS-CoV-2 tests had the best performance characteristics, followed by ELISA then POCT. Given the varied performance characteristics of all the serological assays, there is a need to continuously improve their detection thresholds, as well as to monitor and re-evaluate their performances to assure their significance and applicability for COVID-19 clinical and epidemiological purposes.

Download Full-text

Determination of IgG1 and IgG3 SARS-CoV-2 spike protein and nucleocapsid binding. Who is binding who and why?

10.1101/2021.06.17.21259077 ◽

2021 ◽

Author(s):

Jason K Iles ◽

Raminta Zmuidinaite ◽

Christoph Sadee ◽

Anna Gardiner ◽

Jonathan Lacey ◽

...

Keyword(s):

Immune Response ◽

Humoral Immune Response ◽

Spike Protein ◽

Differential Analysis ◽

Cytokine Release ◽

Spectral Signatures ◽

Humoral Immune ◽

Differential Ability ◽

Control Plasma

The involvement of IgG3 within the humoral immune response to SARS-CoV2 infection has been implicated in the pathogenesis of ARDS in COVID-19. The exact molecular mechanism is unknown but is thought to involve this IgG subtypes differential ability to fix complement and stimulate cytokine release. We examined convalescent patients antibodies binding to immobilised nucleocapsid and spike protein by MALDI-ToF mass spectrometry. IgG3 was a major immunoglobulin found in all samples. Differential analysis of the spectral signatures found for nucleocapsid versus spike protein demonstrated that the predominant humoral immune response to nucleocapsid was IgG3, whilst against spike it was IgG1. However, the spike protein displayed a strong affinity for IgG3 itself which it would bind from control plasma samples as well as from those previously infected with SARS-CoV2, much in the way Protein-G binds IgG1. Furthermore, detailed spectral analysis indicated a mass shift consistent with hyper-glycosylation or glycation was a characteristic of the IgG3 captured by the spike protein.

Download Full-text

Humoral Immune Response Following SARS-CoV-2 Vaccination in Liver Transplant Recipients

Vaccines ◽

10.3390/vaccines9121422 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1422

Author(s):

Lea Timmermann ◽

Brigitta Globke ◽

Georg Lurje ◽

Moritz Schmelzle ◽

Wenzel Schöning ◽

...

Keyword(s):

Immune Response ◽

Liver Transplant ◽

Humoral Immune Response ◽

Seroconversion Rate ◽

Underlying Disease ◽

Immunosuppressive Regimen ◽

Spike Protein ◽

Transplant Recipients ◽

Humoral Immune ◽

Liver Transplant Recipients

As COVID-19 remains an issue in transplantation medicine, a successful vaccination can prevent infections and life-threatening courses. The probability of poor immune response in liver transplant recipients gained attention and insecurity among those patients, leading us to investigate the humoral immune response alongside the influence of underlying diseases and immunosuppressive regimen on seroconversion rates. We included 118 patients undergoing anti-spike-protein-IgG testing at least 21 days after completed SARS-CoV-2 vaccination. Ninety-seven patients also underwent anti-spike-protein-IgA testing. The influence of baseline demographics, immunosuppressive regimen and underlying disease on seroconversion was analyzed, and 92 of 118 patients (78.0%) developed anti-spike-protein-IgG antibodies. Patients with a history of alcoholic liver disease before transplantation showed significantly lower seroconversion rates (p = 0.006). Immunosuppression also significantly influenced antibody development (p < 0.001). Patients run on a mycophenolate mofetil (MMF)-based regimen were more likely not to develop antibodies compared to patients run on a non-MMF regimen (p < 0.001). All patients weaned off immunosuppression were seropositive. The seroconversion rate of 78.0% in our cohort of liver transplant recipients is promising. The identification of alcohol-induced cirrhosis as underlying disease and MMF for immunosuppression as risk factors for seronegativity may serve to identify vaccination non-responder after liver transplantation.

Download Full-text