scholarly journals A Replicating Single-Cycle Adenovirus Vaccine Effective against Clostridium difficile

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 470
Author(s):  
William E. Matchett ◽  
Stephanie Anguiano-Zarate ◽  
Goda Baddage Rakitha Malewana ◽  
Haley Mudrick ◽  
Melissa Weldy ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Neutralizing Antibodies ◽  
Antibody Responses ◽  
Complete Protection ◽  
Single Cycle ◽  
Toxin B ◽  
Toxin Binding ◽  
Binding Domains ◽  
Binding Antibody

Clostridium difficile causes nearly 500,000 infections and nearly 30,000 deaths each year in the U.S., which is estimated to cost $4.8 billion. C. difficile infection (CDI) arises from bacteria colonizing the large intestine and releasing two toxins, toxin A (TcdA) and toxin B (TcdB). Generating humoral immunity against C. difficile’s toxins provides protection against primary infection and recurrence. Thus, a vaccine may offer the best opportunity for sustained, long-term protection. We developed a novel single-cycle adenovirus (SC-Ad) vaccine against C. difficile expressing the receptor-binding domains from TcdA and TcdB. The single immunization of mice generated sustained toxin-binding antibody responses and protected them from lethal toxin challenge for up to 38 weeks. Immunized Syrian hamsters produced significant toxin-neutralizing antibodies that increased over 36 weeks. Single intramuscular immunization provided complete protection against lethal BI/NAP1/027 spore challenge 45 weeks later. These data suggest that this replicating vaccine may prove useful against CDI in humans.

scholarly journals Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies

2021 ◽  
Author(s):  
Claudia A. Jette ◽  
Alexander A. Cohen ◽  
Priyanthi N.P. Gnanapragasam ◽  
Frauke Muecksch ◽  
Yu E. Lee ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Cross Reactivity ◽  
Antibody Therapeutics ◽  
Binding Domains ◽  
Cryptic Epitope ◽  
Binding Antibody ◽  
Β Sheet ◽  
Potent Neutralization

SummaryMany anti-SARS-CoV-2 neutralizing antibodies target the ACE2-binding site on viral spike receptor-binding domains (RBDs). The most potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly-emergent zoonotic sarbecoviruses and variants, but usually show only weak neutralization potencies. We characterized two class 4 anti-RBD antibodies derived from COVID-19 donors that exhibited broad recognition and potent neutralization of zoonotic coronavirus and SARS-CoV-2 variants. C118-RBD and C022-RBD structures revealed CDRH3 mainchain H-bond interactions that extended an RBD β-sheet, thus reducing sensitivity to RBD sidechain changes, and epitopes that extended from the cryptic epitope to occlude ACE2 binding. A C118-spike trimer structure revealed rotated RBDs to allow cryptic epitope access and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics.

scholarly journals Toxin B Variants from Clostridium difficile Strains VPI 10463 and NAP1/027 Share Similar Substrate Profile and Cellular Intoxication Kinetics but Use Different Host Cell Entry Factors

Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 348 ◽  
Author(s):  
Diana López-Ureña ◽  
Josué Orozco-Aguilar ◽  
Yendry Chaves-Madrigal ◽  
Andrea Ramírez-Mata ◽  
Amanda Villalobos-Jimenez ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Small Gtpases ◽  
Cell Entry ◽  
Intestinal Loop ◽  
Loop Model ◽  
Toxin B ◽  
Binding Domains ◽  
Crucial Difference ◽  
Sequence Variations

Clostridium difficile induces antibiotic-associated diarrhea due to the release of toxin A (TcdA) and toxin B (TcdB), the latter being its main virulence factor. The epidemic strain NAP1/027 has an increased virulence attributed to different factors. We compared cellular intoxication by TcdBNAP1 with that by the reference strain VPI 10463 (TcdBVPI). In a mouse ligated intestinal loop model, TcdBNAP1 induced higher neutrophil recruitment, cytokine release, and epithelial damage than TcdBVPI. Both toxins modified the same panel of small GTPases and exhibited similar in vitro autoprocessing kinetics. On the basis of sequence variations in the frizzled-binding domain (FBD), we reasoned that TcdBVPI and TcdBNAP1 might have different receptor specificities. To test this possibility, we used a TcdB from a NAP1 variant strain (TcdBNAP1v) unable to glucosylate RhoA but with the same receptor-binding domains as TcdBNAP1. Cells were preincubated with TcdBNAP1v to block cellular receptors, prior to intoxication with either TcdBVPI or TcdBNAP1. Preincubation with TcdBNAP1v blocked RhoA glucosylation by TcdBNAP1 but not by TcdBVPI, indicating that the toxins use different host factors for cell entry. This crucial difference might explain the increased biological activity of TcdBNAP1 in the intestine, representing a contributing factor for the increased virulence of the NAP1/027 strain.

scholarly journals Pathogenesis of shigella diarrhea. XI. Isolation of a shigella toxin-binding glycolipid from rabbit jejunum and HeLa cells and its identification as globotriaosylceramide.

1986 ◽  
Vol 163 (6) ◽  
pp. 1391-1404 ◽  
Author(s):  
M Jacewicz ◽  
H Clausen ◽  
E Nudelman ◽  
A Donohue-Rolfe ◽  
G T Keusch
Keyword(s):  
Hela Cells ◽  
Neutralizing Antibodies ◽  
Specific Binding ◽  
Jejunal Mucosa ◽  
Toxin B ◽  
Toxin Binding ◽  
B Subunit ◽  
Specific Binding Sites ◽  
Rabbit Jejunum ◽  
Group B

A glycolipid that specifically binds shigella toxin was isolated from both HeLa cells and rabbit jejunal mucosa and identified as globotriaosylceramide (Gb3) by its identical mobility on HPTLC to authentic erythrocyte Gb3. Toxin also bound to a band tentatively identified as alpha-hydroxylated Gb3. In addition, toxin bound to P1 antigen present in group B human erythrocyte glycolipid extracts. The common feature of the three binding glycolipids is a terminal Gal alpha 1----4Gal disaccharide linked beta 1----4 to either Glc or GlcNAc. Globoisotriaosylceramide, which differs from Gb3 only in possessing a Gal alpha 1----3Gal terminal disaccharide, and LacCer, which lacks the terminal Gal residue of Gb3, were incapable of binding the toxin. Binding was shown to be mediated by the B subunit by the use of isolated toxin A and B subunits and monoclonal subunit-specific antibodies. Gb3-containing liposomes competitively inhibited the binding of toxin to HeLa cell monolayers but did not inhibit toxin-induced cytotoxicity. These studies show an identical carbohydrate-specific glycolipid receptor for shigella toxin in gut and in HeLa cells. The toxin B subunit that mediates this binding has also been shown to recognize a glycoprotein receptor with different sugar specificity. Thus, we have demonstrated that the same small (Mr 6,500) B subunit polypeptide has two distinctive carbohydrate-specific binding sites. The Gal alpha 1----4Gal disaccharide of the glycolipid toxin receptor is also recognized by the Gal-Gal pilus of uropathogenic E. coli. This suggests the possibility that the pilus and toxin B subunit contain homologous sequences. If this is true, it may be possible to use the purified Gal-Gal pilus to produce toxin-neutralizing antibodies.

scholarly journals More rapid, robust and sustainable antibody responses to mRNA COVID-19 vaccine in convalescent COVID-19 individuals

2021 ◽  
Author(s):  
Sabrina E Racine-Brzostek ◽  
Jim Yee ◽  
Ashley Sukhu ◽  
Yuqing Qiu ◽  
Sophie Rand ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Antibody Response ◽  
Real World ◽  
Neutralizing Antibodies ◽  
Vaccine Dose ◽  
Antibody Responses ◽  
Antibody Levels

Longitudinal studies are needed to evaluate the SARS-CoV-2 mRNA vaccine antibody response under real-world conditions. This longitudinal study investigated the quantity and quality of SARS-CoV-2 antibody response in 846 specimens from 350 subjects: comparing BNT162b2-vaccinated individuals (19 previously diagnosed with COVID-19 [RecoVax]; 49 never been diagnosed [NaiveVax]) to 122 hospitalized unvaccinated (HospNoVax) and 160 outpatient unvaccinated (OutPtNoVax) COVID-19 patients. NaiveVax experienced a delay in generating SARS-CoV-2 total antibody levels (TAb) and neutralizing antibodies (SNAb) after the 1st vaccine dose (D1), but a rapid increase in antibody levels was observed after the 2nd dose (D2). However, these never reached the robust levels observed in RecoVax. In fact, NaiveVax TAb and SNAb levels decreased 4-weeks post-D2 (p=0.003;p<0.001). For the most part, RecoVax TAb persisted throughout this study, after reaching maximal levels 2-weeks post-D2; but SNAb decreased significantly ~6-months post-D1 (p=0.002). Although NaiveVax avidity lagged behind that of RecoVax for most of the follow-up periods, NaiveVax did reach similar avidity by ~6-months post-D1. These data suggest that one vaccine dose elicits maximal antibody response in RecoVax and may be sufficient. Also, despite decreasing levels in TAb and SNAb overtime, long-term avidity maybe a measure worth evaluating and possibly correlating to vaccine efficacy.

scholarly journals Sex disparities and neutralizing antibody durability to SARS-CoV-2 infection in convalescent individuals

2021 ◽  
Author(s):  
Alena J. Markmann ◽  
Natasa Giallourou ◽  
D. Ryan Bhowmik ◽  
Yixuan J. Hou ◽  
Aaron Lerner ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Human Antibody ◽  
Antibody Titers ◽  
Sex Disparities ◽  
Binding Antibody ◽  
Male Sex ◽  
Antibody Levels ◽  
First Time

AbstractThe coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has now caused over 2 million deaths worldwide and continues to expand. Currently, much is unknown about functionally neutralizing human antibody responses and durability to SARS-CoV-2. Using convalescent sera collected from 101 COVID-19 recovered individuals 21-212 days after symptom onset with forty-eight additional longitudinal samples, we measured functionality and durability of serum antibodies. We also evaluated associations between individual demographic and clinical parameters with functional neutralizing antibody responses to COVID-19. We found robust antibody durability out to six months, as well as significant positive associations with the magnitude of the neutralizing antibody response and male sex. We also show that SARS-CoV-2 convalescent neutralizing antibodies are higher in individuals with cardio-metabolic comorbidities.SignificanceIn this study we found that neutralizing antibody responses in COVID-19 convalescent individuals vary in magnitude but are durable and correlate well with RBD Ig binding antibody levels compared to other SARS-CoV-2 antigen responses. In our cohort, higher neutralizing antibody titers are independently and significantly associated with male sex compared to female sex. We also show for the first time, that higher convalescent antibody titers in male donors are associated with increased age and symptom grade. Furthermore, cardio-metabolic co-morbidities are associated with higher antibody titers independently of sex. Here, we present an in-depth evaluation of serologic, demographic, and clinical correlates of functional antibody responses and durability to SARS-CoV-2.

scholarly journals Neutralizing Antibody Responses following Long-Term Vaccination with HIV-1 Env gp140 in Guinea Pigs

2018 ◽  
Vol 92 (13) ◽  
pp. e00369-18 ◽  
Author(s):  
Christine A. Bricault ◽  
James M. Kovacs ◽  
Alexander Badamchi-Zadeh ◽  
Krisha McKee ◽  
Jennifer L. Shields ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Neutralizing Antibodies ◽  
Antibody Responses ◽  
Tier 2 ◽  
Broadly Neutralizing Antibodies ◽  
Vaccination Regimen ◽  
Tier 1 ◽  
Clade C ◽  
Hiv 1

ABSTRACTA vaccination regimen capable of eliciting potent and broadly neutralizing antibodies (bNAbs) remains an unachieved goal of the HIV-1 vaccine field. Here, we report the immunogenicity of longitudinal prime/boost vaccination regimens with a panel of HIV-1 envelope (Env) gp140 protein immunogens over a period of 200 weeks in guinea pigs. We assessed vaccine regimens that included a monovalent clade C gp140 (C97ZA012 [C97]), a tetravalent regimen consisting of four clade C gp140s (C97ZA012, 459C, 405C, and 939C [4C]), and a tetravalent regimen consisting of clade A, B, C, and mosaic gp140s (92UG037, PVO.4, C97ZA012, and Mosaic 3.1, respectively [ABCM]). We found that the 4C and ABCM prime/boost regimens were capable of eliciting greater magnitude and breadth of binding antibody responses targeting variable loop 2 (V2) over time than the monovalent C97-only regimen. The longitudinal boosting regimen conducted over more than 2 years increased the magnitude of certain tier 1 NAb responses but did not increase the magnitude or breadth of heterologous tier 2 NAb responses. These data suggest that additional immunogen design strategies are needed to induce broad, high-titer tier 2 NAb responses.IMPORTANCEThe elicitation of potent, broadly neutralizing antibodies (bNAbs) remains an elusive goal for the HIV-1 vaccine field. In this study, we explored the use of a long-term vaccination regimen with different immunogens to determine if we could elicit bNAbs in guinea pigs. We found that longitudinal boosting over more than 2 years increased tier 1 NAb responses but did not increase the magnitude and breadth of tier 2 NAb responses. These data suggest that additional immunogen designs and vaccination strategies will be necessary to induce broad tier 2 NAb responses.

scholarly journals A Mixture of Functionally Oligoclonal Humanized Monoclonal Antibodies That Neutralize Clostridium difficile TcdA and TcdB with High Levels ofIn VitroPotency ShowsIn VivoProtection in a Hamster Infection Model

2013 ◽  
Vol 20 (3) ◽  
pp. 377-390 ◽  
Author(s):  
Nicola L. Davies ◽  
Joanne E. Compson ◽  
Brendon MacKenzie ◽  
Victoria L. O'Dowd ◽  
Amanda K. F. Oxbrow ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Clostridium Difficile ◽  
Neutralizing Antibodies ◽  
Disease Process ◽  
Care Facility ◽  
Infection Model ◽  
Hamster Model ◽  
Content Type ◽  
Toxin Binding

ABSTRACTClostridium difficileinfections are a major cause of antibiotic-associated diarrhea in hospital and care facility patients. In spite of the availability of effective antibiotic treatments,C. difficileinfection (CDI) is still a major cause of patient suffering, death, and substantial health care costs.Clostridium difficileexerts its major pathological effects through the actions of two protein exotoxins, TcdA and TcdB, which bind to and disrupt gut tissue. Antibiotics target the infecting bacteria but not the exotoxins. Administering neutralizing antibodies against TcdA and TcdB to patients receiving antibiotic treatment might modulate the effects of the exotoxins directly. We have developed a mixture of three humanized IgG1 monoclonal antibodies (MAbs) which neutralize TcdA and TcdB to address three clinical needs: reduction of the severity and duration of diarrhea, reduction of death rates, and reduction of the rate of recurrence. The UCB MAb mixture showed higher potency in a variety ofin vitrobinding and neutralization assays (∼10-fold improvements), higher levels of protection in a hamster model of CDI (82% versus 18% at 28 days), and higher valencies of toxin binding (12 versus 2 for TcdA and 3 versus 2 for TcdB) than other agents in clinical development. Comparisons of the MAb properties also offered some insight into the potential relative importance of TcdA and TcdB in the disease process.

scholarly journals Systemic Priming-Boosting Immunization with a Trivalent Plasmid DNA and Inactivated Murine Cytomegalovirus (MCMV) Vaccine Provides Long-Term Protection against Viral Replication following Systemic or Mucosal MCMV Challenge

2005 ◽  
Vol 79 (1) ◽  
pp. 159-175 ◽  
Author(s):  
Christopher S. Morello ◽  
Ming Ye ◽  
Stephanie Hung ◽  
Laura A. Kelley ◽  
Deborah H. Spector
Keyword(s):  
Viral Replication ◽  
Salivary Glands ◽  
Plasmid Dna ◽  
Neutralizing Antibodies ◽  
Murine Cytomegalovirus ◽  
Complete Protection ◽  
Challenge Virus ◽  
Target Organs ◽  
Specific Immunoglobulin

ABSTRACT We previously demonstrated that vaccination of BALB/c mice with a pool of 13 plasmid DNAs (pDNAs) expressing murine cytomegalovirus (MCMV) genes followed by formalin-inactivated MCMV (FI-MCMV) resulted in complete protection against viral replication in the spleen and salivary glands following sublethal intraperitoneal (i.p.) challenge. Here, we found that following intranasal (i.n.) challenge, titers of virus in the lungs of the immunized mice were reduced approximately 1,000-fold relative to those for mock-immunized controls. We next sought to extend these results and to determine whether similar protection levels could be achieved by priming with a pool of three pDNAs containing three key plasmids (IE1, M84, and gB). We found that the three-pDNA priming elicited IE1- and M84-p65-specific CD8+ T lymphocytes and, following FI-MCMV boost, high levels of virion-specific immunoglobulin G (IgG) and virus-neutralizing antibodies. When mice were i.n. challenged 4 months after the last boost, titers of virus in the lungs of immunized mice were reduced 1,000- to 2,000-fold from those for controls during the peak of viral replication. Additionally, titers of virus were either at or below the detection limits for the salivary glands, liver, and spleen of the majority of the immunized mice. Following sublethal i.p. challenge, virus was undetectable in all of the above target organs of the immunized mice. Virion-specific IgA in the lungs was consistently detected by day 6 post-i.n. challenge for the immunized mice and by day 14 for controls. These results demonstrate the immunity and high levels of protection of the priming-boosting vaccination against both systemic and mucosal challenge.

scholarly journals Envelope-Modified Single-Cycle Simian Immunodeficiency Virus Selectively Enhances Antibody Responses and Partially Protects against Repeated, Low-Dose Vaginal Challenge

2010 ◽  
Vol 84 (20) ◽  
pp. 10748-10764 ◽  
Author(s):  
Michael D. Alpert ◽  
Andrew R. Rahmberg ◽  
William Neidermyer ◽  
Sharon K. Ng ◽  
Angela Carville ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Low Dose ◽  
Rhesus Macaques ◽  
Antibody Responses ◽  
Viral Gene ◽  
Vaginal Mucosa ◽  
Single Cycle ◽  
Glycosylation Sites ◽  
Immunodeficiency Virus

ABSTRACT Immunization of rhesus macaques with strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection elicits T-cell responses to multiple viral gene products and antibodies capable of neutralizing lab-adapted SIV, but not neutralization-resistant primary isolates of SIV. In an effort to improve upon the antibody responses, we immunized rhesus macaques with three strains of single-cycle SIV (scSIV) that express envelope glycoproteins modified to lack structural features thought to interfere with the development of neutralizing antibodies. These envelope-modified strains of scSIV lacked either five potential N-linked glycosylation sites in gp120, three potential N-linked glycosylation sites in gp41, or 100 amino acids in the V1V2 region of gp120. Three doses consisting of a mixture of the three envelope-modified strains of scSIV were administered on weeks 0, 6, and 12, followed by two booster inoculations with vesicular stomatitis virus (VSV) G trans-complemented scSIV on weeks 18 and 24. Although this immunization regimen did not elicit antibodies capable of detectably neutralizing SIVmac239 or SIVmac251UCD, neutralizing antibody titers to the envelope-modified strains were selectively enhanced. Virus-specific antibodies and T cells were observed in the vaginal mucosa. After 20 weeks of repeated, low-dose vaginal challenge with SIVmac251UCD, six of eight immunized animals versus six of six naïve controls became infected. Although immunization did not significantly reduce the likelihood of acquiring immunodeficiency virus infection, statistically significant reductions in peak and set point viral loads were observed in the immunized animals relative to the naïve control animals.

Sign in / Sign up

Export Citation Format

Share Document