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

Author(s):  
Jason K Iles ◽  
Raminta Zmuidinaite ◽  
Christoph Sadee ◽  
Anna Gardiner ◽  
Jonathan Lacey ◽  
...  

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.

2021 ◽  
Vol 6 (1) ◽  
pp. e000733
Author(s):  
Astrid Muyldermans ◽  
Maria Bjerke ◽  
Thomas Demuyser ◽  
Deborah De Geyter ◽  
Ingrid Wybo ◽  
...  

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Teresa Aydillo ◽  
Alexander Rombauts ◽  
Daniel Stadlbauer ◽  
Sadaf Aslam ◽  
Gabriela Abelenda-Alonso ◽  
...  

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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chengchao Ding ◽  
Jun He ◽  
Xiangyu Zhang ◽  
Chengcheng Jiang ◽  
Yong Sun ◽  
...  

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.


Virus Genes ◽  
2021 ◽  
Author(s):  
Katharina Müller ◽  
Philipp Girl ◽  
Andreas Giebl ◽  
Stefanie Gruetzner ◽  
Markus Antwerpen ◽  
...  

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.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 441
Author(s):  
Hye-Jung Kim ◽  
Hye Won Kwak ◽  
Kyung Won Kang ◽  
Yoo-Jin Bang ◽  
Yu-Sun Lee ◽  
...  

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.


PRILOZI ◽  
2014 ◽  
Vol 35 (3) ◽  
pp. 185-194
Author(s):  
Mirjana Popovska ◽  
Kristina Mitik ◽  
Ladislava Grchevska ◽  
Aneta Atanasovska-Stojanovska ◽  
Biljana Kapushevska ◽  
...  

AbstractAim: To examine the role of IgA, CIC and component C3 as indicators of humoral immune response in the etiopathogenesis of oral erosive lichen planus (OELP).Material and method: The study comprised 19 patients with OELP whose samples of blood, saliva and tissue were obtained after carefully taken medical history and clinical examination. Samples of oral mucosa were taken from the site of lesion, i.e. exclusively from buccal mucosa (1 cm in width and length), and from the deep epithelium as well as a segment from the lamina propria. Determination of immunoglobulins in serum and saliva, and determination of component C3, was done using the micro-elisa technique by Rook & Cameron, Engvall and Ulman. Determination of CIC in serum and mixed saliva was done with the PEG (polyethylene glycol) method. Determination of immunoglobulin A and component C3 in biopsy material was done with direct immunofluorescence.Results: Levels of immunoglobulin A in serum in OELP during exacerbation were decreased (1.04 ± 0.49 gr/l) and during remission increased (5.92 ± 0.62) in comparison with the control group (p < 0.001). Levels of CIC during exacerbation and remission were increased (p < 0.001), and component C3 levels were increased in both examined phases in the examined group compared with the control group (p < 0.05). Deposits of IgA were registered in one (5.88%) patient with OELP and component C3 was registered in 3 (17.64%) patients.Conclusion: Changes in IgA values, as well as CIC and component C3, may correlate with changes in oral mucosa emphasizing the role of humoral immune response in the pathogenesis of oral lichen planus.


Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1422
Author(s):  
Lea Timmermann ◽  
Brigitta Globke ◽  
Georg Lurje ◽  
Moritz Schmelzle ◽  
Wenzel Schöning ◽  
...  

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.


2016 ◽  
Vol 88 (24) ◽  
pp. 12339-12345 ◽  
Author(s):  
María Garranzo-Asensio ◽  
Ana Guzman-Aranguez ◽  
Carmen Povés ◽  
María Jesús Fernández-Aceñero ◽  
Rebeca M. Torrente-Rodríguez ◽  
...  

1998 ◽  
Vol 79 (5) ◽  
pp. 363-366
Author(s):  
E. V. Agafonova ◽  
T. G. Malanicheva ◽  
B. A. Shamov

The examination results of the humoral immune response in children with allergodermatosis and in healthy children of various age groups are presented. The following immune diagnosis methods are used: the determination of the basic class immunoglobulins content, complement activity and general Ig E level. The markers for the immune status estimation and atopic type response prediction taking into account the immune system ontogenesis are proposed.


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