scholarly journals Effect of Deletion of Gene Cluster involved in Synthesis of Enterobacterial Common Antigen on Virulence and Immunogenicity of Live Attenuated Salmonella Vaccine when Delivering Heterologous Streptococcus pneumoniae Antigen PspA

2020 ◽  
Author(s):  
Qing Liu ◽  
Xuegang Shen ◽  
Xiaoping Bian ◽  
Qingke Kong
Keyword(s):  
Vaccine Strain ◽  
Antigen Delivery ◽  
Common Antigen ◽  
Wild Type ◽  
Attenuated Vaccine ◽  
Protective Antigens ◽  
Enterobacterial Common Antigen ◽  
Protection Rate

Abstract Background: Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery.Results: In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen PspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised.Conclusions: ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversible ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.

scholarly journals Effect of Deletion of Gene Cluster involved in Synthesis of Enterobacterial Common Antigen on Virulence and Immunogenicity of Live Attenuated Salmonella Vaccine when Delivering Heterologous Streptococcus pneumoniae Antigen PspA

2020 ◽  
Author(s):  
Qing Liu ◽  
Xuegang Shen ◽  
Xiaoping Bian ◽  
Qingke Kong
Keyword(s):  
Vaccine Strain ◽  
Antigen Delivery ◽  
Common Antigen ◽  
Wild Type ◽  
Attenuated Vaccine ◽  
Protective Antigens ◽  
Enterobacterial Common Antigen ◽  
Protection Rate

Abstract Background: Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery. Results: In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen PspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised. Conclusions: ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversible ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.

scholarly journals Effect of Deletion of Gene Cluster involved in Synthesis of Enterobacterial Common Antigen on Virulence and Immunogenicity of Live Attenuated Salmonella Vaccine when Delivering Heterologous Streptococcus pneumoniae Antigen rPspA

2020 ◽  
Author(s):  
Qing Liu ◽  
Xuegang Shen ◽  
Xiaoping Bian ◽  
Qingke Kong
Keyword(s):  
Vaccine Strain ◽  
Common Antigen ◽  
Wild Type ◽  
Attenuated Vaccine ◽  
Protective Antigens ◽  
Enterobacterial Common Antigen ◽  
Protection Rate ◽  
Pneumococcal Antigen

Abstract Background: Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery.Results: In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen rPspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised.Conclusions: ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversibly ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.

scholarly journals Construction, Genotypic and Phenotypic Characterization, and Immunogenicity of Attenuated ΔguaBA Salmonella enterica Serovar Typhi Strain CVD 915

2001 ◽  
Vol 69 (8) ◽  
pp. 4734-4741 ◽  
Author(s):  
Jin Yuang Wang ◽  
Marcela F. Pasetti ◽  
Fernando R. Noriega ◽  
Richard J. Anderson ◽  
Steven S. Wasserman ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Salmonella Enterica ◽  
Phase 1 ◽  
Lethal Dose ◽  
Phenotypic Characterization ◽  
Typhoid Vaccine ◽  
Wild Type ◽  
Gene Encoding

ABSTRACT A promising live attenuated typhoid vaccine candidate strain for mucosal immunization was developed by introducing a deletion in theguaBA locus of pathogenic Salmonella entericaserovar Typhi strain Ty2. The resultant ΔguaBA mutant, serovar Typhi CVD 915, has a gene encoding resistance to arsenite replacing the deleted sequence within guaBA, thereby providing a marker to readily identify the vaccine strain. CVD 915 was compared in in vitro and in vivo assays with wild-type strain Ty2, licensed live oral typhoid vaccine strain Ty21a, or attenuated serovar Typhi vaccine strain CVD 908-htrA (harboring mutations inaroC, aroD, and htrA). CVD 915 was less invasive than CVD 908-htrA in tissue culture and was more crippled in its ability to proliferate after invasion. In mice inoculated intraperitoneally with serovar Typhi and hog gastric mucin (to estimate the relative degree of attenuation), the 50% lethal dose of CVD 915 (7.7 × 107 CFU) was significantly higher than that of wild-type Ty2 (1.4 × 102 CFU) and was only slightly lower than that of Ty21a (1.9 × 108CFU). Strong serum O and H antibody responses were recorded in mice inoculated intranasally with CVD 915, which were higher than those elicited by Ty21a and similar to those stimulated by CVD 908-htrA. CVD 915 also elicited potent proliferative responses in splenocytes from immunized mice stimulated with serovar Typhi antigens. Used as a live vector, CVD 915(pTETlpp) elicited high titers of serum immunoglobulin G anti-fragment C. These encouraging preclinical data pave the way for phase 1 clinical trials with CVD 915.

scholarly journals Francisella tularensis Live Vaccine Strain Folate Metabolism and Pseudouridine Synthase Gene Mutants Modulate Macrophage Caspase-1 Activation

2012 ◽  
Vol 81 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Tyler K. Ulland ◽  
Ann M. Janowski ◽  
Blake W. Buchan ◽  
Matthew Faron ◽  
Suzanne L. Cassel ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Live Vaccine Strain ◽  
Wild Type ◽  
Content Type ◽  
Pseudouridine Synthase ◽  
Caspase 1

Francisella tularensisis a Gram-negative bacterium and the causative agent of the disease tularemia. Escape ofF. tularensisfrom the phagosome into the cytosol of the macrophage triggers the activation of the AIM2 inflammasome through a mechanism that is not well understood. Activation of the AIM2 inflammasome results in autocatalytic cleavage of caspase-1, resulting in the processing and secretion of interleukin-1β (IL-1β) and IL-18, which play a crucial role in innate immune responses toF. tularensis. We have identified the5-formyltetrahydrofolate cycloligasegene (FTL_0724) as being important forF. tularensislive vaccine strain (LVS) virulence. Infection of micein vivowith aF. tularensisLVSFTL_0724mutant resulted in diminished mortality compared to infection of mice with wild-type LVS. TheFTL_0724mutant also induced increased inflammasome-dependent IL-1β and IL-18 secretion and cytotoxicity in macrophagesin vitro. In contrast, infection of macrophages with aF. tularensisLVSrluD pseudouridine synthase(FTL_0699) mutant resulted in diminished IL-1β and IL-18 secretion from macrophagesin vitrocompared to infection of macrophages with wild-type LVS. In addition, theFTL_0699mutant was not attenuatedin vivo. These findings further illustrate thatF. tularensisLVS possesses numerous genes that influence its ability to activate the inflammasome, which is a key host strategy to control infection with this pathogenin vivo.

scholarly journals Use of a Murine Cytomegalovirus K181-Derived Bacterial Artificial Chromosome as a Vaccine Vector for Immunocontraception

2005 ◽  
Vol 79 (5) ◽  
pp. 2998-3008 ◽  
Author(s):  
Alec J. Redwood ◽  
Martin Messerle ◽  
Nicole L. Harvey ◽  
Christopher M. Hardy ◽  
Ulrich H. Koszinowski ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Murine Cytomegalovirus ◽  
Wild Type ◽  
Vaccine Vectors ◽  
Bac Clone ◽  
Artificial Chromosomes ◽  
Viral Vaccine ◽  
Rapid Production

ABSTRACT Cytomegaloviruses (CMVs) are members of the Betaherpesvirinae subfamily of the Herpesviridae, and their properties of latency, large DNA size, gene redundancy, and ability to be cloned as bacterial artificial chromosomes (BACs) suggest their utility as vaccine vectors. While the K181 strain of murine CMV (MCMV) is widely used to study MCMV biology, a BAC clone of this virus had not previously been produced. We report here the construction of a BAC clone of the K181Perth strain of MCMV. The in vivo and in vitro growth characteristics of virus derived from the K181 BAC were similar to those of wild-type K181. The utility of the K181 BAC as a method for the rapid production of vaccine vectors was assessed. A vaccine strain of BAC virus, expressing the self-fertility antigen, murine zona pellucida 3, was produced rapidly using standard bacterial genetics techniques and rendered female BALB/c mice infertile with a single intraperitoneal inoculation. In addition, attenuated vaccine strains lacking the open reading frames m07 to m12 exhibited no reduction in efficacy compared to the full-length vaccine strain. In conclusion, we describe the production of a K181-based BAC virus which behaved essentially as wild-type K181 and allowed the rapid production of effective viral vaccine vectors.

scholarly journals In Vitro and In Vivo Analyses of Constitutive and In Vivo-Induced Promoters in Attenuated Vaccine and Vector Strains ofVibrio cholerae

2000 ◽  
Vol 68 (3) ◽  
pp. 1171-1175 ◽  
Author(s):  
Manohar John ◽  
Thomas I. Crean ◽  
Stephen B. Calderwood ◽  
Edward T. Ryan
Keyword(s):  
Immune Responses ◽  
Vaccine Strain ◽  
Antigen Expression ◽  
Live Attenuated Vaccine ◽  
Attenuated Vaccine ◽  
In Vivo Expression ◽  
Antibody Titers ◽  
Heterologous Antigens

ABSTRACT The optimal promoter for in vivo expression of heterologous antigens by live, attenuated vaccine vector strains of Vibrio cholerae is unclear; in vitro analyses of promoter activity may not accurately predict expression of antigens in vivo. We therefore introduced plasmids expressing the B subunit of cholera toxin (CtxB) under the control of a number of promoters into V. choleraevaccine strain Peru2. We evaluated the tac promoter, which is constitutively expressed in V. cholerae, as well as the in vivo-induced V. cholerae heat shock htpGpromoter and the in vivo-induced V. cholerae iron-regulatedirgA promoter. The functionality of all promoters was confirmed in vitro. In vitro antigenic expression was highest in vaccine strains expressing CtxB under the control of thetac promoter (2 to 5 μg/ml/unit of optical density at 600 nm [OD600]) and, under low-iron conditions, in strains containing the irgA promoter (5 μg/ml/OD600). We orally inoculated mice with the various vaccine strains and used anti-CtxB immune responses as a marker for in vivo expression of CtxB. The vaccine strain expressing CtxB under the control of thetac promoter elicited the most prominent specific anti-CtxB responses in vivo (serum immunoglobulin G [IgG], P≤ 0.05; serum IgA, P ≤ 0.05; stool IgA,P ≤ 0.05; bile IgA, P ≤ 0.05), despite the finding that the tac and irgApromoters expressed equivalent amounts of CtxB in vitro. Vibriocidal antibody titers were equivalent in all groups of animals. Our results indicate that in vitro assessment of antigen expression by vaccine and vector strains of V. cholerae may correlate poorly with immune responses in vivo and that of the promoters examined, thetac promoter may be best suited for expression from plasmids of at least certain heterologous antigens in such strains.

scholarly journals Preliminary comparative analysis of the genomes of selected field reisolates of the Mycoplasma synoviae vaccine strain MS-H reveals both stable and unstable mutations after passage in vivo

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Somayeh Kordafshari ◽  
Pollob Shil ◽  
Marc S. Marenda ◽  
Olusola M. Olaogun ◽  
Barbara Konsak-Ilievski ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Diagnostic Techniques ◽  
Whole Genome Sequence ◽  
Wild Type ◽  
Coding Region ◽  
Mycoplasma Synoviae ◽  
Unstable Mutations ◽  
The Stability

Abstract Background Genomic comparison of Mycoplasma synoviae vaccine strain MS-H and the MS-H parental strain 86,079/7NS established a preliminary profile of genes related to attenuation of MS-H. In this study we aimed to identify the stability of mutations found in MS-H after passage in experimental or field chickens, and to evaluate if any reverse mutation may be associated with changes in characteristics of MS-H in vitro or in vivo. Results Whole genome sequence analysis of 5 selected MS-H field reisolates revealed that out of 32 mutations reported previously in MS-H, 28 remained stable, while four found to be reversible to the wild-type. Each isolate possessed mutations in one to three of the genes obg, oppF1 and gap and/or a non-coding region. Examination of the 4 reversible mutations by protein modeling predicted that only two of them (in obg and oppF1 genes) could potentially restore the function of the respective protein to that of the wild-type. Conclusions These results suggest that the majority of the MS-H mutations are stable after passage in vaccinated chickens. Characterisation of stable mutations found in MS-H could be utilised to develop rapid diagnostic techniques for differentiation of vaccine from field strains or ts- MS-H reisolates.

scholarly journals Arabidopsis Disulfide Reductase, Trx-h2, Functions as an RNA Chaperone under Cold Stress

2021 ◽  
Vol 11 (15) ◽  
pp. 6865
Author(s):  
Eun Seon Lee ◽  
Joung Hun Park ◽  
Seong Dong Wi ◽  
Ho Byoung Chae ◽  
Seol Ki Paeng ◽  
...  
Keyword(s):  
Cold Stress ◽  
Wild Type ◽  
Rna Chaperone ◽  
E Coli ◽  
Cold Sensitive ◽  
Thioredoxin H ◽  
Functional Rnas

The thioredoxin-h (Trx-h) family of Arabidopsis thaliana comprises cytosolic disulfide reductases. However, the physiological function of Trx-h2, which contains an additional 19 amino acids at its N-terminus, remains unclear. In this study, we investigated the molecular function of Trx-h2 both in vitro and in vivo and found that Arabidopsis Trx-h2 overexpression (Trx-h2OE) lines showed significantly longer roots than wild-type plants under cold stress. Therefore, we further investigated the role of Trx-h2 under cold stress. Our results revealed that Trx-h2 functions as an RNA chaperone by melting misfolded and non-functional RNAs, and by facilitating their correct folding into active forms with native conformation. We showed that Trx-h2 binds to and efficiently melts nucleic acids (ssDNA, dsDNA, and RNA), and facilitates the export of mRNAs from the nucleus to the cytoplasm under cold stress. Moreover, overexpression of Trx-h2 increased the survival rate of the cold-sensitive E. coli BX04 cells under low temperature. Thus, our data show that Trx-h2 performs function as an RNA chaperone under cold stress, thus increasing plant cold tolerance.

scholarly journals Neuroprotective Potential of a Small Molecule RET Agonist in Cultured Dopamine Neurons and Hemiparkinsonian Rats

2021 ◽  
pp. 1-24
Author(s):  
Juho-Matti Renko ◽  
Arun Kumar Mahato ◽  
Tanel Visnapuu ◽  
Konsta Valkonen ◽  
Mati Karelson ◽  
...  
Keyword(s):  
Mapk Signaling ◽  
Dopamine Neurons ◽  
Dopamine Depletion ◽  
Wild Type ◽  
Disease Modifying Therapy ◽  
Immortalized Cells ◽  
Midbrain Dopamine ◽  
6 Hydroxydopamine

Background: Parkinson’s disease (PD) is a progressive neurological disorder where loss of dopamine neurons in the substantia nigra and dopamine depletion in the striatum cause characteristic motor symptoms. Currently, no treatment is able to halt the progression of PD. Glial cell line-derived neurotrophic factor (GDNF) rescues degenerating dopamine neurons both in vitro and in animal models of PD. When tested in PD patients, however, the outcomes from intracranial GDNF infusion paradigms have been inconclusive, mainly due to poor pharmacokinetic properties. Objective: We have developed drug-like small molecules, named BT compounds that activate signaling through GDNF’s receptor, the transmembrane receptor tyrosine kinase RET, both in vitro and in vivo and are able to penetrate through the blood-brain barrier. Here we evaluated the properties of BT44, a second generation RET agonist, in immortalized cells, dopamine neurons and rat 6-hydroxydopamine model of PD. Methods: We used biochemical, immunohistochemical and behavioral methods to evaluate the effects of BT44 on dopamine system in vitro and in vivo. Results: BT44 selectively activated RET and intracellular pro-survival AKT and MAPK signaling pathways in immortalized cells. In primary midbrain dopamine neurons cultured in serum-deprived conditions, BT44 promoted the survival of the neurons derived from wild-type, but not from RET knockout mice. BT44 also protected cultured wild-type dopamine neurons from MPP +-induced toxicity. In a rat 6-hydroxydopamine model of PD, BT44 reduced motor imbalance and could have protected dopaminergic fibers in the striatum. Conclusion: BT44 holds potential for further development into a novel, possibly disease-modifying therapy for PD.

scholarly journals The double-stranded DNA-binding proteins TEBP-1 and TEBP-2 form a telomeric complex with POT-1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sabrina Dietz ◽  
Miguel Vasconcelos Almeida ◽  
Emily Nischwitz ◽  
Jan Schreier ◽  
Nikenza Viceconte ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Wild Type ◽  
C Elegans ◽  
Double Stranded Dna ◽  
Telomere Sequence ◽  
Proteomics Approach ◽  
Telomeric Protein ◽  
Regulate Telomere Length

AbstractTelomeres are bound by dedicated proteins, which protect them from DNA damage and regulate telomere length homeostasis. In the nematode Caenorhabditis elegans, a comprehensive understanding of the proteins interacting with the telomere sequence is lacking. Here, we harnessed a quantitative proteomics approach to identify TEBP-1 and TEBP-2, two paralogs expressed in the germline and embryogenesis that associate to telomeres in vitro and in vivo. tebp-1 and tebp-2 mutants display strikingly distinct phenotypes: tebp-1 mutants have longer telomeres than wild-type animals, while tebp-2 mutants display shorter telomeres and a Mortal Germline. Notably, tebp-1;tebp-2 double mutant animals have synthetic sterility, with germlines showing signs of severe mitotic and meiotic arrest. Furthermore, we show that POT-1 forms a telomeric complex with TEBP-1 and TEBP-2, which bridges TEBP-1/-2 with POT-2/MRT-1. These results provide insights into the composition and organization of a telomeric protein complex in C. elegans.

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