scholarly journals Broadly Neutralizing Hemagglutinin Stalk-Specific Antibodies Induce Potent Phagocytosis of Immune Complexes by Neutrophils in an Fc-Dependent Manner

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Caitlin E. Mullarkey ◽  
Mark J. Bailey ◽  
Diana A. Golubeva ◽  
Gene S. Tan ◽  
Raffael Nachbagauer ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Fc Receptor ◽  
Igg Antibodies ◽  
Specific Antibodies ◽  
Effector Functions ◽  
Iga Antibodies ◽  
Specific Igg ◽  
Optimal Protection ◽  
Specific Igg Antibodies

ABSTRACTBroadly neutralizing antibodies that recognize the conserved hemagglutinin (HA) stalk have emerged as exciting new biotherapeutic tools to combat seasonal and pandemic influenza viruses. Our general understanding of the mechanisms by which stalk-specific antibodies achieve protection is rapidly evolving. It has recently been demonstrated that broadly neutralizing HA stalk-specific IgG antibodies require Fc-Fcγ receptor (FcγR) interactions for optimal protectionin vivo. Here we examine the neutrophil effector functions induced by stalk-specific antibodies. As the most abundant subset of blood leukocytes, neutrophils represent a critical innate effector cell population and serve an instrumental role in orchestrating downstream adaptive responses to influenza virus infection. Yet, the interplay of HA stalk-specific IgG, Fc-FcγR engagement, and neutrophils has remained largely uncharacterized. Using anin vitroassay to detect the production of reactive oxygen species (ROS), we show that human and mouse monoclonal HA stalk-specific IgG antibodies are able to induce the production of ROS by neutrophils, while HA head-specific antibodies do not. Furthermore, our results indicate that the production of ROS is dependent on Fc receptor (FcR) engagement and phagocytosis. We went on to assess the ability of monoclonal HA stalk-specific IgA antibodies to induce ROS. Consistent with our findings for monoclonal IgGs, only HA stalk-specific IgA antibodies elicited ROS production by neutrophils. This induction is dependent on the engagement of FcαR1. Taken together, our findings describe a novel FcR-dependent effector function induced by HA stalk-specific IgG and IgA antibodies, and importantly, our studies shed light on the mechanisms by which HA stalk-specific antibodies achieve protection.IMPORTANCEThe present study provides evidence that broadly neutralizing HA stalk-specific antibodies induce downstream Fc-mediated neutrophil effector functions. In addition to their ability to neutralize, this class of antibodies has been shown to rely on Fc-Fc receptor interactions for optimal protectionin vivo. Curiously, neutralizing antibodies that bind the HA head domain do not require such interactions. Our findings build on these previous observations and provide a more complete picture of the relationship between stalk-specific antibodies and cells of the innate immune compartment. Furthermore, our data suggest that the ability of HA stalk-specific antibodies to mediate Fc-Fc receptor engagement is epitope dependent. Overall, this work will inform the rational design of improved influenza virus vaccines and therapeutics.

scholarly journals Endogenously Produced SARS-CoV-2 Specific IgG Antibodies May Have a Limited Impact on Clearing Nasal Shedding of Virus during Primary Infection in Humans

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 516
Author(s):  
Shuyi Yang ◽  
Keith R. Jerome ◽  
Alexander L. Greninger ◽  
Joshua T. Schiffer ◽  
Ashish Goyal
Keyword(s):  
Production Rate ◽  
Neutralizing Antibodies ◽  
Primary Infection ◽  
Natural Infection ◽  
Viral Clearance ◽  
Clinical Severity ◽  
Igg Antibodies ◽  
Igm Antibodies ◽  
Specific Igg ◽  
Specific Igg Antibodies

While SARS-CoV-2 specific neutralizing antibodies have been developed for therapeutic purposes, the specific viral triggers that drive the generation of SARS-CoV-2 specific IgG and IgM antibodies remain only partially characterized. Moreover, it is unknown whether endogenously derived antibodies drive viral clearance that might result in mitigation of clinical severity during natural infection. We developed a series of non-linear mathematical models to investigate whether SARS-CoV-2 viral and antibody kinetics are coupled or governed by separate processes. Patients with severe disease had a higher production rate of IgG but not IgM antibodies. Maximal levels of both isotypes were governed by their production rate rather than different saturation levels between people. Our results suggest that an exponential surge in IgG levels occurs approximately 5–10 days after symptom onset with no requirement for continual antigenic stimulation. SARS-CoV-2 specific IgG antibodies appear to have limited to no effect on viral dynamics but may enhance viral clearance late during primary infection resulting from the binding effect of antibody to virus, rather than neutralization. In conclusion, SARS-CoV-2 specific IgG antibodies may play only a limited role in clearing infection from the nasal passages despite providing long-term immunity against infection following vaccination or prior infection.

scholarly journals Total serum IgE and parasite: specific IgG and IgA antibodies in human strongyloidiasis

1993 ◽  
Vol 35 (4) ◽  
pp. 361-365 ◽  
Author(s):  
Cláudio L. Rossi ◽  
Emilia E. H. Takahashi ◽  
Cláudia D. Partel ◽  
Lívia G.V.L. Teodoro ◽  
Luiz J. da Silva
Keyword(s):  
Elevated Serum ◽  
Clinical Manifestations ◽  
Case Series ◽  
Total Serum ◽  
Igg Antibodies ◽  
Serum Ige ◽  
Iga Antibodies ◽  
Specific Igg ◽  
Mean Concentration ◽  
Specific Igg Antibodies

Total serum IgE, and Strongyloides - specific IgG and IgA antibodies were studied in 27 patients with parasitologically proven strongyloidiasis. Clinical manifestations in this case series were investigated by a restrospective study of the patient's records. Total serum IgE levels were elevated (greater than 250 IU/ml) in 59% of the patients (mean concentration = 1364 IU/ml). Parasite - specific IgG and IgA antibodies were detected by ELISA in the serum of 23 (85.2%) and 21 (77.8%) patients, respectively. Elevated serum IgE and clinical manifestations were not useful indexes of the presence of strongyloidiasis. On the other hand, our results support the view that serologic tests, particularly ELISA for detecting Strongyloides - specific IgG antibodies, can be usefully exploited for diagnostic purposes in strongyloidiasis.

In vivolocalization of antibodies raised againstEimeria maximawall forming bodies during sexual intracellular development

Parasitology ◽  
2014 ◽  
Vol 141 (13) ◽  
pp. 1726-1735 ◽  
Author(s):  
SONJA FRÖLICH ◽  
ANNISHA SHAHPAREE ◽  
VALERIE C. WASINGER ◽  
MICHAEL WALLACH
Keyword(s):  
Intestinal Lumen ◽  
Igg Antibodies ◽  
Human Pathogens ◽  
Apicomplexan Parasites ◽  
Eimeria Maxima ◽  
Specific Igg ◽  
Cytoplasmic Type ◽  
Specific Igg Antibodies

SUMMARYApicomplexan parasites cause devastating diseases in humans and livestock. Previously we demonstrated that antibodies targeting transmissible forms of the apicomplexan parasite,Eimeria, are effective at reducing parasite shedding thus preventing the transmission of the disease. However, the mechanisms responsible have not been fully defined. Moreover, there is no direct evidence that the parasite-specific IgG antibodies can reach the parasite developing in the enterocytes of the infected chicken host. This study summarizes our efforts using host immunity, parasite proteomics and 3D microscopy to provide a step forward in our understanding of how this immune response works.Eimeria maximais an important pathogen of poultry and used as a surrogate for a number of human pathogens includingToxoplasmaandPlasmodium. Our studies demonstrate that immunization with the purified wall forming bodies (WFBs) results in a production of parasite-specific IgG antibodies, which have the ability to reachin situgametocytes in the intestinal lumen and permeate the enterocyte/parasite membranes in order to bind to the cytoplasmic Type 1 and Type 2 WFBs. This raises the intriguing possibility that via this process antibodies block the development ofEimeria maxima in vivo.

scholarly journals Orthogonal regulation of DNA nanostructure self-assembly and disassembly using antibodies

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Simona Ranallo ◽  
Daniela Sorrentino ◽  
Francesco Ricci
Keyword(s):  
Self Assembly ◽  
Functional Unit ◽  
Tubular Structures ◽  
Igg Antibodies ◽  
Specific Antibodies ◽  
Dna Nanostructure ◽  
Control Assembly ◽  
Recognition Elements ◽  
Specific Igg ◽  
Specific Igg Antibodies

AbstractHere we report a rational strategy to orthogonally control assembly and disassembly of DNA-based nanostructures using specific IgG antibodies as molecular inputs. We first demonstrate that the binding of a specific antibody to a pair of antigen-conjugated split DNA input-strands induces their co-localization and reconstitution into a functional unit that is able to initiate a toehold strand displacement reaction. The effect is rapid and specific and can be extended to different antibodies with the expedient of changing the recognition elements attached to the two split DNA input-strands. Such an antibody-regulated DNA-based circuit has then been employed to control the assembly and disassembly of DNA tubular structures using specific antibodies as inputs. For example, we demonstrate that we can induce self-assembly and disassembly of two distinct DNA tubular structures by using DNA circuits controlled by two different IgG antibodies (anti-Dig and anti-DNP antibodies) in the same solution in an orthogonal way.

scholarly journals Experimental infection with T. canis and T. leonina in farm mink (Neovison vison)

2019 ◽  
Vol 63 (2) ◽  
pp. 197-203 ◽  
Author(s):  
Maciej Klockiewicz ◽  
Tadeusz Jakubowski ◽  
Małgorzata Sobczak-Filipiak ◽  
Justyna Bartosik ◽  
Ewa Długosz
Keyword(s):  
Parasite Species ◽  
Paratenic Host ◽  
Neovison Vison ◽  
Mouse Tissue ◽  
Igg Antibodies ◽  
Faecal Examination ◽  
Specific Igg ◽  
Paratenic Hosts ◽  
Specific Igg Antibodies

AbstractIntroduction: Farm mink (Neovison vison) can be naturally exposed to T. canis and T. leonina pathogens on the farm. If mink were hosts, it would imply some veterinary public health as well as animal welfare issues. For this reason, the aim of the study was to determine whether mink might be definitive or paratenic hosts of these parasites. Material and Methods: Four groups of mink were infected with both parasite species using larvated eggs or feed containing mouse tissue previously infected with the parasites. Following inoculation, the infections were monitored in vivo by faecal examination for 14 weeks p.i., and then western blotting and ELISA were performed. Results: Coprology did not reveal any canine roundworm eggs, neither were nematodes found in mink intestines during post mortem examination. The specific IgG antibodies recognising excretory/secretory (ES) antigens of both parasite species were identified in mink sera. Single T. leonina tissue larvae were found in digested organs. Conclusions: Our results confirm that farm mink may contribute both T. canis and T. leonina infections. It was proved that farm mink were not their definitive hosts, and therefore mink faeces need not be considered a source of canine roundworm eggs in any soil it fertilises. Nonetheless, as farm mink may be a paratenic host for both parasite species, this may have some impact on the health and welfare of infected animals.

scholarly journals Antibody response to SARS-CoV-2 infection and BNT162b2 vaccine in Israel

2021 ◽  
Author(s):  
Guy Shapira ◽  
Ramzia Abu Hamad ◽  
Chen Weiner ◽  
Nir Rainy ◽  
Reut Sorek-Abramovich ◽  
...  
Keyword(s):  
Immune Response ◽  
Viral Entry ◽  
Neutralizing Antibodies ◽  
Host Cells ◽  
Spike Protein ◽  
Igg Antibodies ◽  
Age And Gender ◽  
Specific Igg ◽  
And Gender ◽  
Specific Igg Antibodies

Neutralizing antibodies targeting the Spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) block viral entry to host cells, preventing disease and further spread of the pathogen. The presence of SARS-CoV-2 antibodies in serum is a reliable indicator of infection, used epidemiologically to estimate the prevalence of infection and clinically as a measurement of an antigen-specific immune response. In this study, we analyzed serum Spike protein-specific IgG antibodies from 26,170 samples, including convalescent individuals who had coronavirus disease 2019 (COVID-19) and recipients of the BNT162b2 vaccine. We find distinct serological patterns in COVID-19 convalescent and vaccinated individuals, correlated with age and gender and the presence symptoms.

scholarly journals Examination of convalescents after West Nile fever for the specific IgM, IgG and neutralizing antibodies

2016 ◽  
Vol 21 (2) ◽  
pp. 82-86
Author(s):  
Alla R. Azaryan ◽  
A. A Kozlova ◽  
A. P Grishanova ◽  
E. I Ivashchenko ◽  
G. L Shendo ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Igg Antibodies ◽  
West Nile Fever ◽  
Serum Samples ◽  
West Nile ◽  
Negative Results ◽  
Igm Elisa ◽  
Control Research ◽  
Specific Igg ◽  
Specific Igg Antibodies

The examination was executed in the Astrakhan region over 2013-2014 with participation of three laboratories. In 26 convalescents after West Nile Fever (WNF) with the serological confirmed diagnosis of WNF blood sera were examined. Neurological form of WNF was observed in 8 cases, and febrile form - in 8 convalescents. Sera have been collected in 243-358 days, on average, in 308 days after the beginning of a disease. For their examination there were used IFA-IgM ELISA (MAC-ELISA), IgG ELISA methods as well as neutralization test in Vero E6 cell culture. The results of the examination in 24 of 26 patients (92, 3%) for IgM antibodies to the virus WNF were negative. In two convalescents according to the laboratories in Astrakhan and Moscow in sera there were observed low titers of IgM (1:400) with minor indices of sera optical density (0.3 to 0.4) and negative results in the Volgograd Plague Control Research Institute. Serum samples of other two convalescents were weakly positive or questionable in testing in Volgograd, but were negative when examined in the Institute of Virology. Specific IgG antibodies were detected in 23 of 26 convalescents (88.5%), neutralizing in 22 of 24 (91.7 %). These data confirm the adequacy of the criteria and tactics for WNF serodiagnosis adopted in Russia based on the application of the MAC -ELISA (IFA - IgM).

scholarly journals Clinical and immunological comparisons of the results of testing for COVID-19 of employees of an outpatient medical organization of a large industrial centre during a pandemic

2021 ◽  
Vol 15 (4) ◽  
pp. 161-167
Author(s):  
O. O. Obukhova ◽  
A. N. Trunov ◽  
O. M. Gorbenko ◽  
A. P. Shvayuk ◽  
T. I. Ryabichenko ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Rna Virus ◽  
Community Acquired Pneumonia ◽  
Control Group ◽  
Clinical Implications ◽  
Igg Antibodies ◽  
Medical Organization ◽  
Specific Antibodies ◽  
Specific Igg ◽  
Specific Igg Antibodies

Aim. To determine the presence or absence of specific IgG antibodies against SARS-CoV-2 antigens in outpatient clinic staff and to compare clinical and immunological features from April to August 2020.Materials and Methods. The control group comprised 386 employees of the Novosibirsk City Clinical Polyclinic №13.The determination of IgG antibodies against SARS-CoV-2 antigens in blood serum was performed by using the ELISA method. A real time method of reverse transcription and polymerase chain reaction was used to extract RNA SARS-CoV-2 from nasopharyngeal and oropharyngeal swabs.Results. Specific IgG antibodies against SARS-CoV-2 antigens were detected in 32 (8.42%) employees of the polyclinic. Antibodies were not detected in 91.58% of employees. 9 members (28.12%) had clinical symptoms of varying degrees of disease severity in the group of employees with the presence of antibodies, 4 members of this group (12,51%) had bilateral community-acquired pneumonia with signs of COVID infection, another 5 members (15.61%) with antibodies had signs of ARVI of mild and moderate severity. RNA SARS-CoV-2 in the group of employees with the presence of antibodies and clinical implications was not detected in any case; 23 (71.88%) members with the presence of IgG-antibodies did not have clinical implications of the disease.Conclusion. The presence of specific antibodies against SARS-CoV-2 in employees with clinical implications of COVID-19 without detection of the RNA virus in the biological material is a retrospective confirmation of the etiology of the transferred infection. The detection of specific antibodies in persons who did not have clinical implications can serve as confirmation of the asymptomatic course of the transferred coronavirus infection.

scholarly journals Prospective Cohort Study of the Kinetics of Specific Antibodies to SARS-CoV-2 Infection and to Four SARS-CoV-2 Vaccines Available in Serbia, and Vaccine Effectiveness: A 3-Month Interim Report

Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1031
Author(s):  
Olivera Lijeskić ◽  
Ivana Klun ◽  
Marija Stamenov Djaković ◽  
Nenad Gligorić ◽  
Tijana Štajner ◽  
...  
Keyword(s):  
Real Life ◽  
Vaccine Dose ◽  
Igg Antibodies ◽  
Post Vaccination ◽  
Specific Antibodies ◽  
Real Life Data ◽  
Specific Igg ◽  
Antibody Levels ◽  
Kinetics Of ◽  
Specific Igg Antibodies

Real-life data on the performance of vaccines against SARS-CoV-2 are still limited. We here present the rates of detection and levels of antibodies specific for the SARS-CoV-2 spike protein RBD (receptor binding domain) elicited by four vaccines available in Serbia, including BNT-162b2 (BioNTech/Pfizer), BBIBP-CorV (Sinopharm), Gam-COVID-Vac (Gamaleya Research Institute) and ChAdOx1-S (AstraZeneca), compared with those after documented COVID-19, at 6 weeks and 3 months post first vaccine dose or post-infection. Six weeks post first vaccine dose, specific IgG antibodies were detected in 100% of individuals fully vaccinated with BNT-162b2 (n = 100) and Gam-COVID-Vac (n = 12) and in 81.7% of BBIBP-CorV recipients (n = 148), while one dose of ChAdOx1-S (n = 24) induced specific antibodies in 75%. Antibody levels elicited by BNT-162b2 were higher, while those elicited by BBIBP-CorV were lower, than after SARS-CoV-2 infection. By 3 months post-vaccination, antibody levels decreased but remained ≥20-fold above the cut-off in BNT-162b2 but not in BBIBP-CorV recipients, when an additional 30% were seronegative. For all vaccines, antibody levels were higher in individuals with past COVID-19 than in naïve individuals. A total of twelve new infections occurred within the first 3 months post-vaccination, eight after the first dose of BNT-162b2 and ChAdOx1-S (one each) and BBIBP-CorV (six), and four after full vaccination with BBIBP-CorV, but none required hospitalization.

scholarly journals Tear antibodies to SARS-CoV-2: implications for transmission

2021 ◽  
Author(s):  
Kevin John Selva ◽  
Samantha K Davis ◽  
Ebene R Haycroft ◽  
Wen Shi Lee ◽  
Ester Lopez ◽  
...  
Keyword(s):  
Ocular Surface ◽  
Post Infection ◽  
Antibody Responses ◽  
Healthy Controls ◽  
Igg Antibodies ◽  
Neutralising Antibodies ◽  
Specific Antibodies ◽  
Route Of Transmission ◽  
Specific Igg ◽  
Specific Igg Antibodies

Objectives SARS-CoV-2 can be transmitted by aerosols and the ocular surface may be an important route of transmission. Little is known about protective antibody responses to SARS-CoV-2 in tears after infection or vaccination. We analysed SARS-CoV-2 specific IgG and IgA responses in human tears after either COVID-19 infection or vaccination. Methods We recruited 16 subjects with COVID-19 infection an average of 7 months previously and 15 subjects before and 2 weeks after Comirnaty (Pfizer-BioNtech) vaccination. Plasma, saliva and basal tears were collected. Pre-pandemic plasma, saliva and basal tears from 11 individuals were included as healthy controls. Antibody responses to 5 SARS-CoV-2 antigens were measured via multiplex. Results IgG antibodies to Spike and Nucleoprotein were detected in tears, saliva and plasma from subjects with prior SARS-CoV-2 infection in comparison to uninfected controls. While RBD-specific antibodies were detected in plasma, minimal RBD-specific antibodies were detected in tears and saliva. In contrast, high levels of IgG antibodies to Spike and RBD, but not Nucleoprotein, were induced in tears, saliva and plasma of subjects receiving 2 doses of the Comirnaty vaccine. Increased levels of IgA1 and IgA2 antibodies to SARS-CoV-2 antigens were detected in plasma following infection or vaccination, but were unchanged in tears and saliva. Conclusion Both infection and vaccination induce SARS-CoV-2-specific IgG antibodies in tears. RBD-specific IgG antibodies in tears were induced by vaccination but were not present 7 months post-infection. This suggests neutralising antibodies may be low in the tears late following infection.

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