scholarly journals Modeling the LPS Neutralization Activity of Anti-Endotoxins

Molecules ◽  
2009 ◽  
Vol 14 (5) ◽  
pp. 1869-1888 ◽  
Author(s):  
Chadinee Thippakorn ◽  
Thummaruk Suksrichavalit ◽  
Chanin Nantasenamat ◽  
Tanawut Tantimongcolwat ◽  
Chartchalerm Isarankura-Na-Ayudhya ◽  
...  
Keyword(s):  
Neutralization Activity ◽  
Lps Neutralization

scholarly journals Seroprevalence of SARS-CoV-2, Symptom Profiles and Sero-Neutralization in a Suburban Area, France

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1076
Author(s):  
Anne Gégout Petit ◽  
Hélène Jeulin ◽  
Karine Legrand ◽  
Nicolas Jay ◽  
Agathe Bochnakian ◽  
...  
Keyword(s):  
Odds Ratio ◽  
World Health Organisation ◽  
World Health ◽  
Preventive Effect ◽  
Neutralization Activity ◽  
Symptom Profiles ◽  
The World ◽  
Household Members ◽  
Total Immunoglobulin

The World Health Organisation recommends monitoring the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated anti–SARS-CoV-2 total immunoglobulin (IgT) antibody seroprevalence and in vitro sero-neutralization in Nancy, France, in spring 2020. Individuals were randomly sampled from electoral lists and invited with household members over 5 years old to be tested for anti–SARS-CoV-2 (IgT, i.e., IgA/IgG/IgM) antibodies by ELISA (Bio-rad); the sero-neutralization activity was evaluated on Vero CCL-81 cells. Among 2006 individuals, the raw seroprevalence was 2.1% (95% confidence interval 1.5 to 2.9), was highest for 20- to 34-year-old participants (4.7% (2.3 to 8.4)), within than out of socially deprived area (2.5% vs. 1%, p = 0.02) and with than without intra-family infection (p < 10−6). Moreover, 25% of participants presented at least one COVID-19 symptom associated with SARS-CoV-2 positivity (p < 10−13), with highly discriminant anosmia or ageusia (odds ratio 27.8 [13.9 to 54.5]); 16.3% (6.8 to 30.7) of seropositive individuals were asymptomatic. Positive sero-neutralization was demonstrated in vitro for 31/43 seropositive subjects. Regarding the very low seroprevalence, a preventive effect of the lockdown in March 2020 can be assumed for the summer, but a second COVID-19 wave, as expected, could be subsequently observed in this poorly immunized population.

scholarly journals Neutralization of SARS-CoV-2 with IgG from COVID-19-convalescent plasma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenji Maeda ◽  
Nobuyo Higashi-Kuwata ◽  
Noriko Kinoshita ◽  
Satoshi Kutsuna ◽  
Kiyoto Tsuchiya ◽  
...  
Keyword(s):  
Immune Response ◽  
Clinical Utility ◽  
Plasma Sample ◽  
Temporal Changes ◽  
Rapid Decline ◽  
Multiple Endpoints ◽  
Neutralization Activity ◽  
Neutralizing Activity ◽  
Binding Antibody ◽  
Potent Immune Response

AbstractWhile there are various attempts to administer COVID-19-convalescent plasmas to SARS-CoV-2-infected patients, neither appropriate approach nor clinical utility has been established. We examined the presence and temporal changes of the neutralizing activity of IgG fractions from 43 COVID-19-convalescent plasmas using cell-based assays with multiple endpoints. IgG fractions from 27 cases (62.8%) had significant neutralizing activity and moderately to potently inhibited SARS-CoV-2 infection in cell-based assays; however, no detectable neutralizing activity was found in 16 cases (37.2%). Approximately half of the patients (~ 41%), who had significant neutralizing activity, lost the neutralization activity within ~ 1 month. Despite the rapid decline of neutralizing activity in plasmas, good amounts of SARS-CoV-2-S1-binding antibodies were persistently seen. The longer exposure of COVID-19 patients to greater amounts of SARS-CoV-2 elicits potent immune response to SARS-CoV-2, producing greater neutralization activity and SARS-CoV-2-S1-binding antibody amounts. The dilution of highly-neutralizing plasmas with poorly-neutralizing plasmas relatively readily reduced neutralizing activity. The presence of good amounts of SARS-CoV-2-S1-binding antibodies does not serve as a surrogate ensuring the presence of good neutralizing activity. In selecting good COVID-19-convalescent plasmas, quantification of neutralizing activity in each plasma sample before collection and use is required.

scholarly journals Immunogenicity of HIV-1-Based Virus-Like Particles with Increased Incorporation and Stability of Membrane-Bound Env

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 239
Author(s):  
Christopher A. Gonelli ◽  
Hannah A. D. King ◽  
Charlene Mackenzie ◽  
Secondo Sonza ◽  
Rob J. Center ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Neutralization Activity ◽  
Virus Like Particles ◽  
Antibody Isotypes ◽  
Immunodeficiency Virus ◽  
Proline Substitution ◽  
Membrane Bound ◽  
Antibody Epitopes ◽  
Hiv 1

An optimal prophylactic vaccine to prevent human immunodeficiency virus (HIV-1) transmission should elicit protective antibody responses against the HIV-1 envelope glycoprotein (Env). Replication-incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present virion-associated Env with a native-like structure during vaccination that closely resembles that encountered on infectious virus. Here, we optimized the incorporation of Env into previously designed mature-form VLPs (mVLPs) and assessed their immunogenicity in mice. The incorporation of Env into mVLPs was increased by replacing the Env transmembrane and cytoplasmic tail domains with those of influenza haemagglutinin (HA-TMCT). Furthermore, Env was stabilized on the VLP surface by introducing an interchain disulfide and proline substitution (SOSIP) mutations typically employed to stabilize soluble Env trimers. The resulting mVLPs efficiently presented neutralizing antibody epitopes while minimizing exposure of non-neutralizing antibody sites. Vaccination of mice with mVLPs elicited a broader range of Env-specific antibody isotypes than Env presented on immature VLPs or extracellular vesicles. The mVLPs bearing HA-TMCT-modified Env consistently induced anti-Env antibody responses that mediated modest neutralization activity. These mVLPs are potentially useful immunogens for eliciting neutralizing antibody responses that target native Env epitopes on infectious HIV-1 virions.

scholarly journals Delayed neutralizing antibody response in the acute phase correlates with severe progression of COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hitoshi Kawasuji ◽  
Yoshitomo Morinaga ◽  
Hideki Tani ◽  
Miyuki Kimura ◽  
Hiroshi Yamada ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Neutralization Activity ◽  
Neutralizing Activity ◽  
Time Points ◽  
Moderate Disease ◽  
Activity Dynamics

AbstractAdaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology. Using SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points. Of the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2–12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9–16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%; P = .011). Neutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.

scholarly journals Insights into neutralizing antibody responses in individuals exposed to SARS-CoV-2 in Chile

2021 ◽  
Vol 7 (7) ◽  
pp. eabe6855 ◽  
Author(s):  
Carolina Beltrán-Pavez ◽  
Sebastián Riquelme-Barrios ◽  
Aarón Oyarzún-Arrau ◽  
Aracelly Gaete-Argel ◽  
Roxana González-Stegmaier ◽  
...  
Keyword(s):  
General Population ◽  
Local Level ◽  
Neutralizing Antibody ◽  
Host Immunity ◽  
Antibody Responses ◽  
Wild Type ◽  
Neutralization Activity ◽  
Future Studies

Chile has one of the worst numbers worldwide in terms of SARS-CoV-2 positive cases and COVID-19–related deaths per million inhabitants; thus, characterization of neutralizing antibody (NAb) responses in the general population is critical to understanding of immunity at the local level. Given our inability to perform massive classical neutralization assays due to the scarce availability of BSL-3 facilities in the country, we developed and fully characterized an HIV-based SARS-CoV-2 pseudotype, which was used in a 96-well plate format to investigate NAb responses in samples from individuals exposed to SARS-CoV-2 or treated with convalescent plasma. We also identified samples with decreased or enhanced neutralization activity against the D614G spike variant compared with the wild type, indicating the relevance of this variant in host immunity. The data presented here represent the first insights into NAb responses in individuals from Chile, serving as a guide for future studies in the country.

scholarly journals Identification of SARS-CoV-2-against aptamer with high neutralization activity by blocking the RBD domain of spike protein 1

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ge Yang ◽  
Ziyue Li ◽  
Irfan Mohammed ◽  
Liping Zhao ◽  
Wei Wei ◽  
...  
Keyword(s):  
Spike Protein ◽  
Neutralization Activity

Generation and In-planta expression of a recombinant single chain antibody with broad neutralization activity on Bothrops pauloensis snake venom

2020 ◽  
Vol 149 ◽  
pp. 1241-1251
Author(s):  
Jessica B. Souza ◽  
Rone Cardoso ◽  
Hebréia O. Almeida-Souza ◽  
Camila P. Carvalho ◽  
Lucas Ian Veloso Correia ◽  
...  
Keyword(s):  
Snake Venom ◽  
In Planta ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Neutralization Activity

scholarly journals Evaluation of Fab and F(ab′)2 Fragments and Isotype Variants of a Recombinant Human Monoclonal Antibody against Shiga Toxin 2

2010 ◽  
Vol 78 (3) ◽  
pp. 1376-1382 ◽  
Author(s):  
Donna E. Akiyoshi ◽  
Abhineet S. Sheoran ◽  
Curtis M. Rich ◽  
L. Richard ◽  
Susan Chapman-Bonofiglio ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Shiga Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Human Monoclonal Antibody ◽  
Chinese Hamster ◽  
The Body ◽  
Neutralization Activity ◽  
Shiga Toxin 2

ABSTRACT 5C12 HuMAb is a human monoclonal antibody against the A subunit of Shiga toxin 2 (Stx2). We have previously shown that 5C12 HuMAb effectively neutralizes the cytotoxic effects of this toxin by redirecting its transport within the cell and also by neutralizing the toxin's ability to inhibit protein synthesis. The 5C12 HuMAb and its recombinant IgG1 version protect mice at a dose of 0.6 μg against a lethal challenge of Stx2. The contribution of the Fc region to this observed neutralization activity of the 5C12 antibody against Stx2 was investigated in this study. Using recombinant DNA technology, 5C12 isotype variants (IgG1, IgG2, IgG3, and IgG4) and antibody fragments [Fab, F(ab′)2] were expressed in Chinese hamster ovary cells and evaluated in vitro and in vivo. All four 5C12 isotype variants showed protection in vitro, with the IgG3 and IgG4 variants showing the highest protection in vivo. The Fab and F(ab′)2 fragments also showed protection in vitro but no protection in the mouse toxicity model. Similar results were obtained for a second HuMAb (5H8) against the B subunit of Stx2. The data suggest the importance of the Fc region for neutralization activity, but it is not clear if this is related to the stability of the full-length antibody or if the Fc region is required for effective elimination of the toxin from the body.

Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity

Vaccine ◽  
2013 ◽  
Vol 31 (44) ◽  
pp. 5009-5014 ◽  
Author(s):  
Phillip R. Pittman ◽  
Diana Fisher ◽  
Xiaofei Quinn ◽  
Trevor Schmader ◽  
Julio G. Barrera-Oro
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Vaccine Dose ◽  
Lethal Toxin ◽  
Neutralization Activity ◽  
Anthrax Vaccine
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