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

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.

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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.

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Immunological imprinting of the antibody response in COVID-19 patients

Nature Communications ◽

10.1038/s41467-021-23977-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Teresa Aydillo ◽

Alexander Rombauts ◽

Daniel Stadlbauer ◽

Sadaf Aslam ◽

Gabriela Abelenda-Alonso ◽

...

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Antibody Response ◽

Humoral Immune Response ◽

Nucleocapsid Protein ◽

Spike Protein ◽

Ongoing Research ◽

Variable Regions ◽

Humoral Immune ◽

Human Coronaviruses

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.

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TLR4 regulates rabies virus-induced humoral immunity through recruitment of cDC2 to lymph organs

Journal of Virology ◽

10.1128/jvi.00829-21 ◽

2021 ◽

Author(s):

Chen Chen ◽

Chengguang Zhang ◽

Haoqi Li ◽

Zongmei Wang ◽

Yueming Yuan ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Rabies Virus ◽

Humoral Immunity ◽

Humoral Immune Response ◽

Critical Role ◽

Wild Type ◽

Humoral Immune ◽

Specific Igg ◽

Molecular Patterns

Rabies, caused by rabies virus (RABV), is fatal to both humans and animals around the world. Effective clinical therapy for rabies has not been achieved, and vaccination is the most effective means of preventing and controlling rabies. Although different vaccines, such as live attenuated and inactivated vaccines, can induce different immune responses, different expression of pattern recognition receptors (PRRs) also causes diverse immune responses. Toll-like receptor 4 (TLR4) is a pivotal PRR that induces cytokine production and bridges innate and adaptive immunity. Importantly, TLR4 recognizes various virus-derived pathogen-associated molecular patterns (PAMPs) and virus-induced damage-associated molecular patterns (DAMPs), usually leading to the activation of immune cells. However, the role of TLR4 in the humoral immune response induced by RABV has not been revealed yet. Based on TLR4-deficient ( TLR4 -/- ) and wild-type (WT) mouse models, we report that TLR4-dependent recruitment of the conventional type-2 dendritic cells (CD8α - CD11b + cDC2) into secondary lymph organs (SLOs) is critical for antigen presentation. cDC2-initiated differentiation of Tfh cells promotes the proliferation of germinal centre (GC) B cells, the formation of GCs, and the production of plasma cells (PCs), all of which contribute to the production of RABV-specific IgG and virus-neutralizing antibodies (VNAs). Collectively, our work demonstrates that TLR4 is necessary for the recruitment of cDC2 and for the induction of RABV-induced humoral immunity, which is regulated by the cDC2-Tfh-GC B axis. IMPORTANCE Vaccination is the most efficient method to prevent rabies. TLR4, a well-known immune sensor, plays a critical role in initiating innate immune response. Here, we found that TLR4 deficiency ( TLR4 -/- ) mice suppressed the induction of humoral immune response after immunization with rabies virus (RABV), including reduced production of VNAs and RABV-specific IgG, compared with that occurred in wild-type (WT) mice. As a consequence, TLR4 -/- mice exhibited higher mortality than WT mice after challenge with virulent RABV. Importantly, further investigation found that TLR4 signaling promoted the recruitment of cDC2 (CD8α + CD11b - ), a subset of cDCs known to induce CD4 + T cell immunity through their MHC-II presentation machinery. Our results imply that TLR4 is indispensable for an efficient humoral response to rabies vaccine, which provides new insight into the development of novel rabies vaccines.

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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.

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The Humoral Immune Response to Various Domains of Protective Antigen of Bacillus anthracis in Cutaneous Anthrax Cases in India

Defence Science Journal ◽

10.14429/dsj.66.10805 ◽

2016 ◽

Vol 66 (6) ◽

pp. 645 ◽

Cited By ~ 3

Author(s):

Anshul Varshney ◽

Nidhi Puranik ◽

M. Kumar ◽

A.K. Goel

Keyword(s):

Immune Response ◽

Bacillus Anthracis ◽

Humoral Immune Response ◽

Vaccine Development ◽

Protective Antigen ◽

Lethal Factor ◽

Serum Samples ◽

Public Health Importance ◽

Humoral Immune ◽

Cutaneous Anthrax

Anthrax, caused by Bacillus anthracis is known to occur globally since antiquity. Besides being an important biothreat agent, it is an important public health importance pathogen also in countries like India. B. anthracis secretes three distinct toxins, namely protective antigen (PA), lethal factor (LF) and edema factor (EF). PA is the central moiety of the anthrax toxin complex and therefore has been a molecule of choice for vaccine development. PA has four different domains with different functions. In this study, the major domains of PA were cloned and expressed in bacterial system. The purified recombinant proteins were used to determine the humoral immune response by ELISA using 43 human cutaneous anthrax serum samples. The maximum immunoreactivity was observed with the whole PA protein followed by domain 2, 4 and 1. The study corroborated that in addition to full PA, individual domain 2 and 4 can also be good target for vaccine development as well as for serodiagnostic assays for cutaneous anthrax

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Role of Bordetella bronchisepticaFimbriae in Tracheal Colonization and Development of a Humoral Immune Response

Infection and Immunity ◽

10.1128/iai.68.4.2024-2033.2000 ◽

2000 ◽

Vol 68 (4) ◽

pp. 2024-2033 ◽

Cited By ~ 66

Author(s):

Seema Mattoo ◽

Jeff F. Miller ◽

Peggy A. Cotter

Keyword(s):

Immune Response ◽

Humoral Immune Response ◽

Limit Of Detection ◽

Immunoglobulin M ◽

Tissue Culture Cell ◽

Wild Type ◽

Humoral Immune ◽

Tract Infections

ABSTRACT Fimbriae are filamentous, cell surface structures which have been proposed to mediate attachment of Bordetella species to respiratory epithelium. Bordetella bronchiseptica has four known fimbrial genes: fim2, fim3,fimX, and fimA. While these genes are unlinked on the chromosome, their protein products are assembled and secreted by a single apparatus encoded by the fimBCD locus. ThefimBCD locus is embedded within the fha operon, whose genes encode another putative adhesin, filamentous hemagglutinin (FHA). We have constructed a Fim− B. bronchiseptica strain, RB63, by introducing an in-frame deletion extending from fimB through fimD. Western blot analysis showed that RB63 is unable to synthesize fimbriae but is unaffected for FHA expression. Using this mutant, we assessed the role of fimbriae in pathogenesis in vitro and in vivo in natural animal hosts. Although RB63 was not significantly defective in its ability to adhere to various tissue culture cell lines, including human laryngeal HEp-2 cells, it was considerably altered in its ability to cause respiratory tract infections in rats. The number of ΔfimBCD bacteria recovered from the rat trachea at 10 days postinoculation was significantly decreased compared to that of wild-type B. bronchiseptica and was below the limit of detection at 30 and 60 days postinoculation. The number of bacteria recovered from the nasal cavity and larynx was not significantly different between RB63 and the wild-type strain at any time point. The ability of fimbriae to mediate initial attachment to tracheal tissue was tested in an intratracheal inoculation assay. Significantly fewer RB63 than wild-type bacteria were recovered from the tracheas at 24 h after intratracheal inoculation. These results demonstrate that fimbriae are involved in enhancing the ability of B. bronchiseptica to establish tracheal colonization and are essential for persistent colonization at this site. Interestingly, anti-Bordetella serum immunoglobulin M (IgM) levels were significantly lower in animals infected with RB63 than in animals infected with wild-type B. bronchiseptica at 10 days postinoculation. Even at 30 days postinoculation, RB63-infected animals had lower serum anti-Bordetella antibody titers in general. This disparity in antibody profiles suggests that fimbriae are also important for the induction of a humoral immune response.

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Antibody response against HERV-W env surface peptides differentiates multiple sclerosis and neuromyelitis optica spectrum disorder

Multiple Sclerosis Journal - Experimental Translational and Clinical ◽

10.1177/2055217317742425 ◽

2017 ◽

Vol 3 (4) ◽

pp. 205521731774242 ◽

Cited By ~ 1

Author(s):

Giannina Arru ◽

Elia Sechi ◽

Sara Mariotto ◽

Alessia Farinazzo ◽

Chiara Mancinelli ◽

...

Keyword(s):

Multiple Sclerosis ◽

Immune Response ◽

Neuromyelitis Optica ◽

Humoral Immune Response ◽

Serum Levels ◽

Spectrum Disorder ◽

Antigenic Peptides ◽

Neuromyelitis Optica Spectrum Disorder ◽

Serum Samples ◽

Humoral Immune

Background A specific humoral immune response against HERV-W envelope surface (env-su) glycoprotein antigens has been reported in serum of patients with multiple sclerosis (MS). However, it has not been evaluated to date in patients with neuromyelitis optica spectrum disorder (NMOSD). Objective The objective of this paper is to investigate whether antibody (Ab) response against HERV-W env-su antigenic peptides differs between NMOSD and MS. Methods Serum samples were collected from 36 patients with NMOSD, 36 patients with MS and 36 healthy control individuals (HCs). An indirect ELISA was set up to detect specific Abs against HERV-W env-su peptides. Results Our data showed that two antigenic peptides, particularly HERV-Wenv93–108 and HERV-Wenv248–262, were statistically significantly present only in serum of MS compared to NMOSD and HCs. Thus, the specific humoral immune response against HERV-W env-su glycoprotein antigens found in MS is widely missing in NMOSD. Conclusion Increased circulating serum levels of these HERV-W Abs may be suitable as additional biomarkers to better differentiate MS from NMOSD.

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SARS-CoV-2 neutralizing antibody treatment in COVID-19 patients with immunodeficiency due to B-cell non-Hodgkin lymphoma

Blood Advances ◽

10.1182/bloodadvances.2021006655 ◽

2021 ◽

Author(s):

Jakob J Malin ◽

Veronica Di Cristanziano ◽

Carola Horn ◽

Elisabeth Pracht ◽

Jorge Garcia Borrega ◽

...

Keyword(s):

Immune Response ◽

B Cell ◽

Hodgkin Lymphoma ◽

Humoral Immune Response ◽

Passive Immunization ◽

Neutralizing Antibody ◽

Common Finding ◽

Antibody Treatment ◽

Humoral Immune ◽

Non Hodgkin Lymphoma

Humoral immunodeficiency is a common finding in patients with B-cell related malignancies such as Non-Hodgkin lymphoma. Failure to induce a sufficient humoral immune response to viral pathogens such as SARS-CoV-2 can result in impaired viral clearance with prolonged viral shedding and symptomatic infections. Here we describe six COVID-19 patients with B-cell Non-Hodgkin lymphoma and impaired humoral immune response that were successfully treated with SARS-CoV-2 neutralizing monoclonal antibodies (nMABs) between June and October 2021. Patients exhibited serological vaccination failure or were unable to clear SARS-CoV-2 even after prolonged infections. Two patients presented with persistent COVID-19 for more than three months. One patient suffered from a third episode of COVID-19 despite vaccination and one patient was diagnosed by SARS-CoV-2 viremia and a positive PCR from the lower respiratory tract while subsequent nasopharyngeal swabs remained negative. In the six described cases, passive immunization with nMABs resulted in rapid and sustained clinical improvement and decrease in viral loads. SARS-CoV-2 nMABs provide a highly attractive treatment option for COVID-19 patients unable to mount a humoral immune response following vaccination or infection.

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Humoral Response to Microbial Biomarkers in Rheumatoid Arthritis Patients

Journal of Clinical Medicine ◽

10.3390/jcm10215153 ◽

2021 ◽

Vol 10 (21) ◽

pp. 5153

Author(s):

Seyedesomaye Jasemi ◽

Gian Luca Erre ◽

Maria Luisa Cadoni ◽

Marco Bo ◽

Leonardo A. Sechi

Keyword(s):

Rheumatoid Arthritis ◽

Immune Response ◽

Humoral Immune Response ◽

Humoral Response ◽

Human Endogenous Retrovirus ◽

Serum Samples ◽

Humoral Immune ◽

Bivariate Correlation ◽

Microbial Biomarkers ◽

Significant Difference

Background/Objective: Chronic humoral immune response against multiple microbial antigens may play a crucial role in the etiopathogenesis of rheumatoid arthritis (RA). We aimed to assess the prevalence and magnitude of antibody response against various bacterial and viral immunogen peptides in the sera of RA patients compared with the general population. Methods: Polyclonal IgG antibodies (Abs) specific for peptides derived from Porphyromonas gingivalis (RgpA, Kpg), Aggregatibacter actinomycetemcomitans (LtxA1, LtxA2), Mycobacterium avium subsp. paratuberculosis (MAP4027), Epstein–Barr virus (EBNA1, EBVBOLF), and human endogenous retrovirus (HERV-W env-su) were detected by ELISA in serum samples from 148 consecutive RA patients and 148 sex and age-matched healthy controls (HCs). In addition, the presence of a relationship between the positivity and the titer of antibodies and RA descriptors was explored by bivariate correlation analysis. Results: RA patients exhibit a higher prevalence of humoral immune response against all tested peptides compared to HCs with a statically significant difference for MAP4027 (30.4% vs. 10.1%), BOLF (25.7% vs. 8.1%), RgpA (24.3% vs. 9.4%), HERV W-env (20.3% vs. 9.4%), and EBNA1 (18.9% vs. 9.4%) peptides. Fifty-three (35.8%) out of 148 RA serum and 93 (62.8%) out of 148 HCs were negative for all pathogen-derived peptides. There was a significant correlation between OD values obtained by ELISA test against all peptides (p < 0.0001). We also found an increased titer and prevalence of Abs against LtxA1 and LtxA2 in seropositive vs. seronegative RF (p = 0.019, p = 0.018). Conclusion: This study demonstrates a significantly increased humoral response against multiple pathogens in patients with RA and implies that they could be an important factor in the pathogenesis of the disease. Therefore, the role of each individual pathogen in RA needs to be further investigated.

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Evaluation of Passive Immunity Induced by Immunisation Using Two Inactivated gE-deleted Marker Vaccines against Infectious Bovine Rhinotracheitis (IBR) in Calves

Vaccines ◽

10.3390/vaccines8010014 ◽

2020 ◽

Vol 8 (1) ◽

pp. 14

Author(s):

Stefano Petrini ◽

Cecilia Righi ◽

Carmen Iscaro ◽

Giulio Viola ◽

Paola Gobbi ◽

...

Keyword(s):

Immune Response ◽

Humoral Immune Response ◽

Calf Serum ◽

Passive Immunity ◽

Control Group ◽

Infectious Bovine Rhinotracheitis ◽

Serum Samples ◽

Glycoprotein E ◽

Humoral Immune ◽

Newborn Calves

Different types of vaccines against Infectious Bovine Rhinotracheitis (IBR) are commercially available. Among these, inactivated glycoprotein E (gE)-deleted marker vaccines are commonly used, but their ability to induce passive immunity is poorly known. Here, we evaluated the passive immunity transferred from dams immunised with commercial inactivated gE-deleted marker vaccines to calves. We vaccinated 12 pregnant cattle devoid of neutralising antibodies against Bovine alphaherpesvirus 1 (BoHV-1) and divided them into two groups with 6 animals each. Both groups were injected with a different inactivated gE-deleted marker vaccine administrated via intranasal or intramuscular routes. An additional 6 pregnant cattle served as the unvaccinated control group. After calving, the number of animals in each group was increased by the newborn calves. In the dams, the humoral immune response was evaluated before calving and, subsequently, at different times until post-calving day 180 (PCD180). In addition, the antibodies in colostrum, milk, and in serum samples from newborn calves were evaluated at different times until PCD180. The results indicated that inactivated glycoprotein E (gE)-deleted marker vaccines are safe and produce a good humoral immune response in pregnant cattle until calving and PCD180. Moreover, results showed that, in calf serum, passive immunity persists until PCD180.

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