scholarly journals Characterization of SARS-CoV-2-specific humoral immunity and its potential applications and therapeutic prospects

Author(s):  
Jiaxin Zheng ◽  
Yingying Deng ◽  
Zhenyu Zhao ◽  
Binli Mao ◽  
Mengji Lu ◽  
...  

AbstractCoronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing pandemic that poses a great threat to human health worldwide. As the humoral immune response plays essential roles in disease occurrence and development, understanding the dynamics and characteristics of virus-specific humoral immunity in SARS-CoV-2-infected patients is of great importance for controlling this disease. In this review, we summarize the characteristics of the humoral immune response after SARS-CoV-2 infection and further emphasize the potential applications and therapeutic prospects of SARS-CoV-2-specific humoral immunity and the critical role of this immunity in vaccine development. Notably, serological antibody testing based on the humoral immune response can guide public health measures and control strategies; however, it is not recommended for population surveys in areas with very low prevalence. Existing evidence suggests that asymptomatic individuals have a weaker immune response to SARS-CoV-2 infection, whereas SARS-CoV-2-infected children have a more effective humoral immune response than adults. The correlations between antibody (especially neutralizing antibody) titers and protection against SARS-CoV-2 reinfection should be further examined. In addition, the emergence of cross-reactions among different coronavirus antigens in the development of screening technology and the risk of antibody-dependent enhancement related to SARS-CoV-2 vaccination should be given further attention.

2021 ◽  
Author(s):  
Chen Chen ◽  
Chengguang Zhang ◽  
Haoqi Li ◽  
Zongmei Wang ◽  
Yueming Yuan ◽  
...  

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.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1411-1411
Author(s):  
Ronald P. Taylor ◽  
Emily C. Whipple ◽  
Margaret A. Lindorfer ◽  
Andrew H. Ditto ◽  
Ryan S. Shanahan

Abstract Complement (C) plays a critical role in the immune response by opsonizing immune complexes (IC) and thymus-independent type 2 antigens with C3 breakdown product C3dg. We investigated the in vivo fate and handling in mice of anti-CR1/CR2 mAb 7G6. We used this rat IgG mAb as a surrogate for C3dg-opsonized IC; mAb 7G6 binds to CR1/CR2 with high affinity, blocks C3dg binding and saturates mouse B cell CR2 at inputs of only 2 ug. RIA, flow cytometry, and fluorescence immunohistochemistry were used to examine the disposition of 0.5–2 ug quantities of mAb 7G6 infused i.v. in mice. The mAb binds to circulating B cells and in the spleen binds preferentially to marginal zone (MZ) B cells. However, within 24 h MZ B cells relocate and transfer the mAb to regions rich in follicular dendritic cells (FDC). Localization of intact antigen to FDC should induce a substantial immune response, and therefore we immunized mice and monkeys i.v. with low doses (1–20 ug/kg) of prototype antigens constructed with anti-CR1/2 mAb 7G6 or anti-CR2 mAb HB135, respectively. We observed a strong immune response characterized by early development of IgG antibodies and long-lasting immunity extending out to at least one year. We applied our immunization paradigm to mouse IgG idiotypes, based on i.v. infusion of mouse IgG2a mAbs which were cross-linked with mAb 7G6. The purpose of these experiments was to determine if tolerance can be broken in order to develop a more powerful vaccine strategy to induce a cytotoxic humoral immune response to malignant B cells based on targeting the idiotype of immunoglobulin molecules expressed on their surfaces. I.V. immunization with the constructs indeed generated a mouse IgG1 immune response to two different mouse IgG2a mAbs, as demonstrated by ELISA. The immune response was idiotype specific, but some anti-isotype antibodies were also detected. Moreover, sera from immunized mice immunoprecipitated the specific radiolabeled mouse mAbs in the presence of 7.5% polyethylene glycol. This humoral immune response was also demonstrable in flow cytometry assays in which IgG1 in sera of immunized mice bound to erythrocytes opsonized with bispecific mAb constructs consisting of the IgG2a mAb crosslinked with an anti-CR1 mAb. The present approach, based on coupling the targeted immunoglobulin to an anti-CR2 mAb for delivery to FDC, may lead to a more effective immunotherapeutic vaccine compared to methods currently in clinical trials which require use of glutaraldehyde to effect crosslinking of the targeted immunoglobulin to KLH.


2016 ◽  
Vol 66 (6) ◽  
pp. 645 ◽  
Author(s):  
Anshul Varshney ◽  
Nidhi Puranik ◽  
M. Kumar ◽  
A.K. Goel

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


Author(s):  
Jakob J Malin ◽  
Veronica Di Cristanziano ◽  
Carola Horn ◽  
Elisabeth Pracht ◽  
Jorge Garcia Borrega ◽  
...  

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.


2002 ◽  
Vol 70 (8) ◽  
pp. 4158-4164 ◽  
Author(s):  
Nicole Reiche ◽  
Andreas Jung ◽  
Thomas Brabletz ◽  
Tanja Vater ◽  
Thomas Kirchner ◽  
...  

ABSTRACT Infection with Helicobacter pylori is chronic despite a vigorous cellular and humoral immune response and causes severe pathology in some patients. In this study, phage display was used as a new approach in order to investigate the role of the host's humoral immune response in the pathogenesis of H. pylori gastritis. Human monoclonal single-chain Fv (scFv) antibody fragments against H. pylori cell lysate and the H. pylori urease were isolated from an immune phage display library, constructed from peripheral blood lymphocytes of an H. pylori-infected patient. After affinity selection, 23% of the clones tested showed binding activity against a lysate of the H. pylori Sydney strain in enzyme-linked immunosorbent assay (ELISA) and 9% bound the H. pylori urease. Further characterization by PCR-fingerprint analysis and sequencing revealed that two closely related H. pylori binders and one antiurease scFv could be isolated. The selected scFvs were highly specific as analyzed by ELISA and immunoblots using various bacterial lysates and recombinant proteins. Analysis of the humoral immune response following H. pylori infection using human monoclonal antibodies might contribute to a better understanding of the pathogenesis of the disease. Moreover, using immune phage display libraries, it might be possible for relevant epitopes of H. pylori antigens to be determined, which might be of use for vaccine development.


2021 ◽  
pp. 135245852110493
Author(s):  
Gabriel Bsteh ◽  
Sophie Dürauer ◽  
Hamid Assar ◽  
Harald Hegen ◽  
Bettina Heschl ◽  
...  

Background: Knowledge on immunity after SARS-CoV-2 infection in patients with multiple sclerosis (pwMS) and the impact of disease-modifying treatment (DMT) is limited. Objective: To evaluate degree, duration and potential predictors of specific humoral immune response in pwMS with prior COVID-19. Methods: Anti-SARS-CoV-2 antibody testing was performed in pwMS with PCR-confirmed diagnosis of symptomatic COVID-19 from a nation-wide registry. Predictors of seropositivity were identified by multivariate regression models. Results: In 125 pwMS (mean age = 42.4 years (SD = 12.3 years), 70% female), anti-SARS-CoV-2 antibodies were detected in 76.0% after a median of 5.2 months from positive PCR. Seropositivity rate was significantly lower in patients on IS-DMT (61.4%, p = 0.001) than without DMT or immunomodulatory DMT (80.6%; 86.0%, respectively). In multivariate analysis, IS-DMT was associated with reduced probability of seropositivity (odds ratio (OR): 0.51; 95% confidence interval (95% CI): 0.17–0.82; p < 0.001). Predefined subgroup analyses showed marked reduction of seropositivity in pwMS on rituximab/ocrelizumab (OR 0.15; 95% CI: 0.05–0.56; p < 0.001). Rate of seropositivity did not change significantly over 6 months. Conclusions: Humoral immunity is stable after SARS-CoV-2 infection in MS, but is reduced by immunosuppressive DMT, particularly anti-CD20 monoclonal antibodies. This provides important evidence for advising pwMS as well as for planning and prioritizing vaccination.


Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 880 ◽  
Author(s):  
Gökce Nur Cagatay ◽  
Denise Meyer ◽  
Michael Wendt ◽  
Paul Becher ◽  
Alexander Postel

Atypical porcine pestivirus (APPV) is a widely distributed pathogen causing congenital tremor (CT) in piglets. So far, no data are available regarding the humoral immune response against APPV. In this study, piglets and their sows from an affected herd were tested longitudinally for viral genome and antibodies. APPV genome was detected in the majority of the piglets (14/15) from CT affected litters. Transient infection of gilts was observed. Kinetics of Erns- and E2-specific antibodies and their neutralizing capacity were determined by recently (Erns) and newly (E2) developed antibody ELISAs and virus neutralization assays. Putative maternally derived antibodies (MDA) were detected in most piglets, but displayed only low to moderate neutralizing capacity (ND50 ≤ 112). Horizontal APPV transmission occurred when uninfected and infected piglets were mingled on the flat deck. Horizontally infected piglets were clinically inapparent and showed only transient viremia with subsequently consistently high E2 antibody levels. For piglets from CT affected litters, significantly lower neutralizing antibody titers were observed. Results indicate that E2 represents the main target of neutralizing antibodies. Characterization of the humoral immune response against APPV will help to provide valuable serological diagnosis, to understand the epidemiology of this novel pathogen, and to implement tailored prevention strategies.


2021 ◽  
Vol 8 ◽  
Author(s):  
Brittany A. Comunale ◽  
Lilly Engineer ◽  
Yong Jiang ◽  
John C. Andrews ◽  
Qianna Liu ◽  
...  

Background: Millions have been exposed to SARS-CoV-2, but the severity of resultant infections has varied among adults and children, with adults presenting more serious symptomatic cases. Children may possess an immunity that adults lack, possibly from childhood vaccinations. This retrospective study suggests immunization against the poliovirus may provide an immunity to SARS-CoV-2.Methods: Publicly available data were analyzed for possible correlations between national median ages and epidemiological outbreak patterns across 100 countries. Sera from 204 adults and children, who were immunized with the poliovirus vaccine, were analyzed using an enzyme-linked immunosorbent assay. The effects of polio-immune serum on SARS-CoV-2-induced cytopathology in cell culture were then evaluated.Results: Analyses of median population age demonstrated a positive correlation between median age and SARS-CoV-2 prevalence and death rates. Countries with effective poliovirus immunization protocols and younger populations have fewer and less pathogenic cases of COVID-19. Antibodies to poliovirus and SARS-CoV-2 were found in pediatric sera and in sera from adults recently immunized with polio. Sera from polio-immunized individuals inhibited SARS-CoV-2 infection of Vero cell cultures. These results suggest the anti-D3-pol-antibody, induced by poliovirus vaccination, may provide a similar degree of protection from SARS-CoV-2 to adults as to children.Conclusions: Poliovirus vaccination induces an adaptive humoral immune response. Antibodies created by poliovirus vaccination bind the RNA-dependent RNA polymerase (RdRp) protein of both poliovirus and SARS-CoV-2, thereby preventing SARS-CoV-2 infection. These findings suggest proteins other than “spike” proteins may be suitable targets for immunity and vaccine development.


2021 ◽  
Vol 6 (2) ◽  
pp. 47-57
Author(s):  
E. A. Novikova ◽  
A. G. Petrova ◽  
E. V. Moskaleva ◽  
A. S. Vanyarkinа ◽  
L. V. Rychkova

Last year the COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has started. The new coronavirus is highly contagious and causes severe complications. The mechanisms of humoral immunity and kinetics of SARS-CoV-2 specific antibodies in a population are not well understood. Therefore, we aimed to summarize and analyze numerous global and Russian serological studies for understanding dynamics of the SARSCoV-2 humoral immune response and getting an accurate picture of the seroprevalence to SARS-CoV-2 in the world population. The PubMed and e-library databases were searched from February 2020 to March 2021 using terms “SARSCoV-2”, “antibodies”, “humoral immunity”. At the beginning of the pandemic first studies were cross-sectional by design and were responsible for determination of the seropositivity and for understanding the fundamental humoral immunity parameters of SARS-CoV-2. Since then, longitudinal seroepidemiological studies have been studying antibody kinetics. Seroconversion time for IgM, IgG antibodies varies, but most researchers report the seroconversion of IgM from the 1st to 14th days after the onset of clinical manifestations, and the seroconversion for IgG is around the 14th day with a concentration peak by the 21st day. Regarding seroprevalence we may say about low herd immunity at the COVID-19 pandemic. Thus, global seroprevalence is about 10 %, and more than 20 % for regions with high incidence and among healthcare workers. Seroprevalence studies have to be continued for more accurate monitoring of long-term humoral immunity to SARS-CoV-2, because the majority of the world’s population is still susceptible to SARS-CoV-2 infection. 


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