scholarly journals Neutralizing Antibodies Elicited by a Novel Detoxified Pneumolysin Derivative, PlyD1, Provide Protection against Both Pneumococcal Infection and Lung Injury

2012 ◽  
Vol 80 (6) ◽  
pp. 2212-2220 ◽  
Author(s):  
Danielle Salha ◽  
Jason Szeto ◽  
Lisa Myers ◽  
Carol Claus ◽  
Anthony Sheung ◽  
...  
Keyword(s):  
Lung Injury ◽  
Neutralizing Antibodies ◽  
Pneumococcal Pneumonia ◽  
Protective Efficacy ◽  
Pneumococcal Infection ◽  
Polyclonal Antiserum ◽  
Candidate Vaccine ◽  
Vaccine Antigen ◽  
Lung Lesions

ABSTRACTStreptococcus pneumoniaepneumolysin (PLY) is a virulence factor that causes toxic effects contributing to pneumococcal pneumonia. To date, deriving a PLY candidate vaccine with the appropriate detoxification and immune profile has been challenging. A pneumolysin protein that is appropriately detoxified and that retains its immunogenicity is a desirable vaccine candidate. In this study, we assessed the protective efficacy of our novel PlyD1 detoxified PLY variant and investigated its underlying mechanism of protection. Results have shown that PlyD1 immunization protected mice against lethal intranasal (i.n.) challenge with pneumococci and lung injury mediated by PLY challenge. Protection was associated with PlyD1-specific IgG titers andin vitroneutralization titers. Pretreatment of PLY with PlyD1-specific rat polyclonal antiserum prior to i.n. delivery of toxin reduced PLY-mediated lung lesions, interleukin-6 (IL-6) production, and neutrophil infiltration into lungs, indicating that protection from lung lesions induced by PLY is antibody mediated. Preincubation of PLY with a neutralizing monoclonal PLY antibody also specifically reduced the cytotoxic effects of PLY after i.n. inoculation in comparison to nonneutralizing monoclonal antibodies. These results indicate that the induction of neutralizing antibodies against PLY can contribute to protection against bacterial pneumonia by preventing the development of PLY-induced lung lesions and inflammation. Our detoxified PlyD1 antigen elicits such PLY neutralizing antibodies, thus serving as a candidate vaccine antigen for the prevention of pneumococcal pneumonia.

scholarly journals Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Protein co-immunization in rhesus macaques

2021 ◽  
Author(s):  
Margherita Rosati ◽  
Mahesh Agarwal ◽  
Xintao Hu ◽  
Santhi Devasundaram ◽  
Dimitris Stellas ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Anatomical Site ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Antibody Titers ◽  
Cellular Immune

The speed of development, versatility and efficacy of mRNA-based vaccines have been amply demonstrated in the case of SARS-CoV-2. DNA vaccines represent an important alternative since they induce both humoral and cellular immune responses in animal models and in human trials. We tested the immunogenicity and protective efficacy of DNA-based vaccine regimens expressing different prefusion-stabilized SARS-CoV-2 Spike antigens upon intramuscular injection followed by electroporation in rhesus macaques. Different Spike DNA vaccine regimens induced antibodies that potently neutralized SARS-CoV-2 in vitro and elicited robust T cell responses. The DNA-only vaccine regimens were compared to a regimen that included co-immunization of Spike DNA and protein in the same anatomical site, the latter of which showed significant higher antibody responses. All vaccine regimens led to control of SARS-CoV-2 intranasal/intratracheal challenge and absence of virus dissemination to the lower respiratory tract. Vaccine-induced binding and neutralizing antibody titers and antibody-dependent cellular phagocytosis inversely correlated with transient virus levels in the nasal mucosa. Importantly, the Spike DNA+Protein co-immunization regimen induced the highest binding and neutralizing antibodies and showed the strongest control against SARS-CoV-2 challenge in rhesus macaques.

scholarly journals Establishment of pan-Influenza A (H1-H18) and pan-Influenza B (pre-split, Vic/Yam) Pseudotype Libraries for efficient vaccine antigen selection

2021 ◽  
Author(s):  
Joanne M Del Rosario ◽  
Kelly da Costa ◽  
Benedikt Asbach ◽  
Francesca Ferrara ◽  
Matteo Ferrari ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Influenza A ◽  
Influenza Viruses ◽  
Vaccine Antigen ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Strategic Objectives ◽  
Influenza Hemagglutinin ◽  
Dosing Regimens

We have developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18, and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for de-tecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza serological and neutralization assays. We demonstrate its utility in detecting serum response to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further pre-clinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response.

Immunogenicity and in vitro protective efficacy of a polyepitope Plasmodium falciparum candidate vaccine constructed by epitope shuffling

Vaccine ◽  
2007 ◽  
Vol 25 (28) ◽  
pp. 5155-5165 ◽  
Author(s):  
Qiliang Cai ◽  
Guiying Peng ◽  
Lingyi Bu ◽  
Yahui Lin ◽  
Lianhui Zhang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Protective Efficacy ◽  
Candidate Vaccine

scholarly journals An Immunogenic and Protective Alphavirus Replicon Particle-Based Dengue Vaccine Overcomes Maternal Antibody Interference in Weanling Mice

2007 ◽  
Vol 81 (19) ◽  
pp. 10329-10339 ◽  
Author(s):  
Laura J. White ◽  
Melissa M. Parsons ◽  
Alan C. Whitmore ◽  
Brandon M. Williams ◽  
Aravinda de Silva ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Neutralizing Antibody ◽  
Gene Cassette ◽  
Vero Cells ◽  
Envelope Proteins ◽  
Maternal Antibodies ◽  
Booster Immunization ◽  
Replicon Particle

ABSTRACT A candidate pediatric dengue virus (DENV) vaccine based on nonpropagating Venezuelan equine encephalitis virus replicon particles (VRP) was tested for immunogenicity and protective efficacy in weanling mice in the presence and absence of potentially interfering maternal antibodies. A gene cassette encoding envelope proteins prM and E from mouse-adapted DENV type 2 (DENV2) strain NGC was cloned into a VEE replicon vector and packaged into VRP, which programmed proper in vitro expression and processing of DENV2 envelope proteins upon infection of Vero cells. Primary immunization of 3-week-old weanling BALB/c mice in the footpad with DENV2 VRP resulted in high levels of DENV-specific serum immunoglobulin G antibodies and significant titers of neutralizing antibodies in all vaccinates. A booster immunization 12 weeks after the prime immunization resulted in increased neutralizing antibodies that were sustained for at least 30 weeks. Immunization at a range of doses of DENV2 VRP protected mice from an otherwise-lethal intracranial DENV2 challenge. To model vaccination in the presence of maternal antibodies, weanling pups born to DENV2-immune or DENV2-naïve dams were immunized with either DENV2 VRP or live DENV2 given peripherally. The DENV2 VRP vaccine induced neutralizing-antibody responses in young mice regardless of the maternal immune status. In contrast, live-DENV2 vaccination performed poorly in the presence of preexisting anti-DENV2 antibodies. This study demonstrates the feasibility of a VRP vaccine approach as an early-life DENV vaccine in populations with high levels of circulating DENV antibodies and suggests the utility of VRP-based vaccines in other instances where maternal antibodies make early vaccination problematic.

scholarly journals Influence of N-Linked Glycosylation of Porcine Reproductive and Respiratory Syndrome Virus GP5 on Virus Infectivity, Antigenicity, and Ability To Induce Neutralizing Antibodies

2006 ◽  
Vol 80 (8) ◽  
pp. 3994-4004 ◽  
Author(s):  
Israrul H. Ansari ◽  
Byungjoon Kwon ◽  
Fernando A. Osorio ◽  
Asit K. Pattnaik
Keyword(s):  
Amino Acid ◽  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Neutralizing Antibody ◽  
Respiratory Syndrome Virus ◽  
Virus Infectivity ◽  
Neutralization Epitope ◽  
Enhanced Sensitivity

ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) glycoprotein 5 (GP5) is the most abundant envelope glycoprotein and a major inducer of neutralizing antibodies in vivo. Three putative N-linked glycosylation sites (N34, N44, and N51) are located on the GP5 ectodomain, where a major neutralization epitope also exists. To determine which of these putative sites are used for glycosylation and the role of the glycan moieties in the neutralizing antibody response, we generated a panel of GP5 mutants containing amino acid substitutions at these sites. Biochemical studies with expressed wild-type (wt) and mutant proteins revealed that the mature GP5 contains high-mannose-type sugar moieties at all three sites. These mutations were subsequently incorporated into a full-length cDNA clone. Our data demonstrate that mutations involving residue N44 did not result in infectious progeny production, indicating that N44 is the most critical amino acid residue for infectivity. Viruses carrying mutations at N34, N51, and N34/51 grew to lower titers than the wt PRRSV. In serum neutralization assays, the mutant viruses exhibited enhanced sensitivity to neutralization by wt PRRSV-specific antibodies. Furthermore, inoculation of pigs with the mutant viruses induced significantly higher levels of neutralizing antibodies against the mutant as well as the wt PRRSV, suggesting that the loss of glycan residues in the ectodomain of GP5 enhances both the sensitivity of these viruses to in vitro neutralization and the immunogenicity of the nearby neutralization epitope. These results should have great significance for development of PRRSV vaccines of enhanced protective efficacy.

scholarly journals The Scavenger Receptor MARCO Is Required for Lung Defense against Pneumococcal Pneumonia and Inhaled Particles

2004 ◽  
Vol 200 (2) ◽  
pp. 267-272 ◽  
Author(s):  
Mohamed Arredouani ◽  
Zhiping Yang ◽  
YaoYu Ning ◽  
Guozhong Qin ◽  
Raija Soininen ◽  
...  
Keyword(s):  
Pneumococcal Pneumonia ◽  
Inflammatory Responses ◽  
Scavenger Receptor ◽  
Pneumococcal Infection ◽  
Innate Defense ◽  
Inhaled Particles ◽  
Lung Defense

Alveolar macrophages (AMs) express the class A scavenger receptor macrophage receptor with collagenous structure (MARCO), but its role in vivo in lung defense against bacteria and environmental particles has not been studied. We used MARCO-deficient mice to directly test the in vivo role of AM MARCO in innate defense against pneumococcal infection and environmental particles. In a murine model of pneumococcal pneumonia, MARCO−/− mice displayed an impaired ability to clear bacteria from the lungs, increased pulmonary inflammation and cytokine release, and diminished survival. In vitro binding of Streptococcus pneumoniae and in vivo uptake of unopsonized particles by MARCO−/− AMs were dramatically impaired. MARCO−/− mice treated with the “inert” environmental particle TiO2 showed enhanced inflammation and chemokine expression, indicating that MARCO-mediated clearance of inert particles by AMs prevents inflammatory responses otherwise initiated by other lung cells. Our findings point to an important role of MARCO in mounting an efficient and appropriately regulated innate immune response against inhaled particles and airborne pathogens.

scholarly journals Recombinant Chimeric Yellow Fever-Dengue Type 2 Virus Is Immunogenic and Protective in Nonhuman Primates

2000 ◽  
Vol 74 (12) ◽  
pp. 5477-5485 ◽  
Author(s):  
F. Guirakhoo ◽  
R. Weltzin ◽  
T. J. Chambers ◽  
Z.-X. Zhang ◽  
K. Soike ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Infectious Clone ◽  
Vero Cells ◽  
Control Group ◽  
Placebo Control ◽  
Wild Type

ABSTRACT A chimeric yellow fever (YF)-dengue type 2 (dengue-2) virus (ChimeriVax-D2) was constructed using a recombinant cDNA infectious clone of a YF vaccine strain (YF 17D) as a backbone into which we inserted the premembrane (prM) and envelope (E) genes of dengue-2 virus (strain PUO-218 from a case of dengue fever in Bangkok, Thailand). The chimeric virus was recovered from the supernatant of Vero cells transfected with RNA transcripts and amplified once in these cells to yield a titer of 6.3 log10 PFU/ml. The ChimeriVax-D2 was not neurovirulent for 4-week-old outbred mice inoculated intracerebrally. This virus was evaluated in rhesus monkeys for its safety (induction of viremia) and protective efficacy (induction of anti-dengue-2 neutralizing antibodies and protection against challenge). In one experiment, groups of non-YF-immune monkeys received graded doses of ChimeriVax-D2; a control group received only the vaccine diluents. All monkeys (except the control group) developed a brief viremia and showed no signs of illness. Sixty-two days postimmunization, animals were challenged with 5.0 log10focus forming units (FFU) of a wild-type dengue-2 virus. No viremia (<1.7 log10 FFU/ml) was detected in any vaccinated group, whereas all animals in the placebo control group developed viremia. All vaccinated monkeys developed neutralizing antibodies in a dose-dependent response. In another experiment, viremia and production of neutralizing antibodies were determined in YF-immune monkeys that received either ChimeriVax-D2 or a wild-type dengue-2 virus. Low viremia was detected in ChimeriVax-D2-inoculated monkeys, whereas all dengue-2-immunized animals became viremic. All of these animals were protected against challenge with a wild-type dengue-2 virus, whereas all YF-immune monkeys and nonimmune controls became viremic upon challenge. Genetic stability of ChimeriVax-D2 was assessed by continuous in vitro passage in VeroPM cells. The titer of ChimeriVax-D2, the attenuated phenotype for 4-week-old mice, and the sequence of the inserted prME genes were unchanged after 18 passages in Vero cells. The high replication efficiency, attenuation phenotype in mice and monkeys, immunogenicity and protective efficacy, and genomic stability of ChimeriVax-D2 justify it as a novel vaccine candidate to be evaluated in humans.

scholarly journals Exploiting Pan Influenza A and Pan Influenza B Pseudotype Libraries for Efficient Vaccine Antigen Selection

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 741
Author(s):  
Joanne Marie M. Del Rosario ◽  
Kelly A. S. da Costa ◽  
Benedikt Asbach ◽  
Francesca Ferrara ◽  
Matteo Ferrari ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Influenza A ◽  
Influenza Viruses ◽  
Vaccine Antigen ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Strategic Objectives ◽  
Influenza Hemagglutinin ◽  
Dosing Regimens

We developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18 and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for detecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza neutralization assays. We demonstrate their utility in detecting serum responses to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further preclinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response.

scholarly journals Cross-Strain Neutralizing and Protective Monoclonal Antibodies against EEEV or WEEV

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2231
Author(s):  
Amanda L. Phelps ◽  
Lyn M. O’Brien ◽  
David O. Ulaeto ◽  
Frederick W. Holtsberg ◽  
Grant C. Liao ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Clinical Signs ◽  
Single Strain ◽  
Neutralization Activity ◽  
Control And Prevention ◽  
Virus Exposure ◽  
Western Equine Encephalitis

The three encephalitic alphaviruses, namely, the Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV), are classified by the Centers for Disease Control and Prevention (CDC) as biothreat agents. Currently, no licensed medical countermeasures (MCMs) against these viruses are available for humans. Neutralizing antibodies (NAbs) are fast-acting and highly effective MCMs for use in both pre- and post-exposure settings against biothreat agents. While significant work has been done to identify anti-VEEV NAbs, less has been done to identify NAbs against EEEV and WEEV. In order to develop anti-EEEV or -WEEV NAbs, mice were immunized using complementary strategies with a variety of different EEEV or WEEV immunogens to maximize the generation of NAbs to each of these viruses. Of the hybridomas generated, three anti-EEEV and seven anti-WEEV monoclonal antibodies were identified with in vitro neutralization activity. The most potent neutralizers (two anti-EEEV NAbs and three anti-WEEV NAbs) were further evaluated for neutralization activity against additional strains of EEEV, a single strain of Madariaga virus (formerly South American EEEV), or WEEV. Of these, G1-2-H4 and G1-4-C3 neutralized all three EEEV strains and the Madariaga virus strain, whereas G8-2-H9 and 12 WA neutralized six out of eight WEEV strains. To determine the protective efficacy of these NAbs, the five most potent neutralizers were evaluated in respective mouse aerosol challenge models. All five NAbs demonstrated various levels of protection when administered at doses of 2.5 mg/kg or 10 mg/kg 24 h before the respective virus exposure via the aerosol route. Of these, anti-EEEV NAb G1-4-C3 and anti-WEEV NAb 8C2 provided 100% protection at both doses and all surviving mice were free of clinical signs throughout the study. Additionally, no virus was detected in the brain 14 days post virus exposure. Taken together, efficacious NAbs were developed that demonstrate the potential for the development of cross-strain antibody-based MCMs against EEEV and WEEV infections.

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