scholarly journals Recombinant GRA4 or ROP2 Protein Combined with Alum or the gra4 Gene Provides Partial Protection in Chronic Murine Models of Toxoplasmosis

2004 ◽  
Vol 11 (4) ◽  
pp. 704-710 ◽  
Author(s):  
Valentina Martin ◽  
Alicia Supanitsky ◽  
Pablo C. Echeverria ◽  
Silvana Litwin ◽  
Tamara Tanos ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Open Reading Frame ◽  
Interleukin 4 ◽  
Murine Models ◽  
Protective Level ◽  
Partial Protection ◽  
Reading Frame ◽  
C3h Mice ◽  
Entire Open Reading Frame ◽  
Brain Cysts

ABSTRACT The efficacy of vaccination with Toxoplasma gondii recombinant GRA4 (rGRA4) and ROP2 (rRPO2) proteins and a mix of both combined with alum were evaluated in C57BL/6 and C3H mice. In C57BL/6 mice, rGRA4 and rGRA4-rROP2 immunizations generated similar levels of immunoglobulin G1 (IgG1) and IgG2a isotypes against GRA4, whereas immunizations with rROP2 and the mix induced a predominant IgG1 production against ROP2. All groups of C3H vaccinated mice exhibited higher levels of IgG1 than IgG2a. rGRA4-stimulated splenocytes from vaccinated mice produced primarily gamma interferon while those stimulated with rROP2 produced interleukin-4. Challenge of rGRA4- or rGRA4-rROP2-vaccinated mice from both strains with ME49 cysts resulted in fewer brain cysts than the controls, whereas vaccination with rROP2 alone only conferred protection to C3H mice. Immunization with a plasmid carrying the entire open reading frame of GRA4 showed a protective level similar to that of rGRA4 combined with alum. These results suggest that GRA4 can be a good candidate for a multiantigen anti-T. gondii vaccine based on the use of alum as an adjuvant.

scholarly journals DNA Vaccination with Genes EncodingToxoplasma gondii Antigens GRA1, GRA7, and ROP2 Induces Partially Protective Immunity against Lethal Challenge in Mice

2000 ◽  
Vol 68 (1) ◽  
pp. 38-45 ◽  
Author(s):  
M. Vercammen ◽  
T. Scorza ◽  
K. Huygen ◽  
J. De Braekeleer ◽  
R. Diet ◽  
...  
Keyword(s):  
Survival Rates ◽  
Dna Vaccination ◽  
High Ratio ◽  
Interleukin 4 ◽  
Mouse Strains ◽  
Lethal Challenge ◽  
C3h Mice ◽  
Ifn Γ ◽  
Brain Cysts ◽  
First Time

ABSTRACT C57BL/6, C3H, and BALB/c mice were vaccinated with plasmids encoding Toxoplasma gondii antigens GRA1, GRA7, and ROP2, previously described as strong inducers of immunity. Seroconversion for the relevant antigen was obtained in the majority of the animals.T. gondii lysate stimulated specific T-cell proliferation and secretion of gamma interferon (IFN-γ) in spleen cell cultures from vaccinated BALB/c and C3H mice but not in those from control mice. Although not proliferating, stimulated splenocytes from DNA-vaccinated C57BL/6 mice also produced IFN-γ. No interleukin-4 was detected in the supernatants of lysate-stimulated splenocytes from DNA-vaccinated mice in any of the mouse strains evaluated. As in infected animals, a high ratio of specific immunoglobulin G2a (IgG2a) to IgG1 antibodies was found in DNA-vaccinated C3H mice, suggesting that a Th1-type response had been induced. For BALB/c mice, the isotype ratio of the antibody response to DNA vaccination was less polarized. The protective potential of DNA vaccination was demonstrated in C3H mice. C3H mice vaccinated with plasmid encoding GRA1, GRA7, or ROP2 were partially protected against a lethal oral challenge with cysts of two differentT. gondii strains: survival rates increased from 10% in controls to at least 70% after vaccination in one case and from 50% to at least 90% in the other. In vaccinated C3H mice challenged with a nonlethal T. gondii dose, the number of brain cysts was significantly lower than in controls. DNA vaccination did not protect BALB/c or C57BL/6 mice. Our results demonstrate for the first time in an animal model a partially protective effect of DNA vaccination against T. gondii.

scholarly journals Regulation of an Osmoticum-Responsive Gene in Anabaena sp. Strain PCC 7120

1998 ◽  
Vol 180 (23) ◽  
pp. 6332-6337 ◽  
Author(s):  
Steven H. Schwartz ◽  
Todd A. Black ◽  
Karin Jäger ◽  
Jean-Michel Panoff ◽  
C. Peter Wolk
Keyword(s):  
Genomic Sequence ◽  
Response Regulator ◽  
Sequence Similarity ◽  
Open Reading Frame ◽  
Response Regulators ◽  
Reading Frame ◽  
Regulatory Systems ◽  
Entire Open Reading Frame ◽  
Anabaena Sp ◽  
Pcc 7120

ABSTRACT Salt-induced genes in the cyanobacterium Anabaena sp. strain PCC 7120 were identified by use of a Tn5-based transposon bearing luxAB as a reporter. The genomic sequence adjacent to one site of insertion of the transposon was identical in part to the sequence of thelti2 gene, which was previously identified in a differential screen for cold-induced transcripts in Anabaena variabilis. The lti2-like gene was induced by sucrose and other osmotica and by low temperature, in addition to salt. Regulatory components necessary for the induction of this gene by osmotica were sought by a further round of transposon mutagenesis. One mutant that displayed reduced transcriptional activity of thelti2-like gene in response to exposure to osmotica had an insertion in an open reading frame, which was denoted orrA, whose predicted product showed sequence similarity to response regulators from two-component regulatory systems. The corresponding mutation was reconstructed and was shown, like the second-site transposon mutation, to result in reduced response to osmotic stress. Induction of the lux reporter gene by osmotica was restored by complementation with a genomic fragment containing the entire open reading frame for the presumptive response regulator, whereas a fragment containing a truncated copy of the open reading frame for the response regulator did not complement the mutation.

scholarly journals Molecular Cloning, Sequencing, Expression, and Characterization of an Immunogenic 43-Kilodalton Lipoprotein of Bartonella bacilliformis That Has Homology to NlpD/LppB

2000 ◽  
Vol 68 (9) ◽  
pp. 4972-4979 ◽  
Author(s):  
Indira Padmalayam ◽  
Timothy Kelly ◽  
Barbara Baumstark ◽  
Robert Massung
Keyword(s):  
Bartonella Henselae ◽  
High Titer ◽  
Polyclonal Antiserum ◽  
Open Reading Frame ◽  
Bartonella Bacilliformis ◽  
Reading Frame ◽  
Dna Library ◽  
Bacillary Angiomatosis ◽  
Genomic Dna Library ◽  
Entire Open Reading Frame

ABSTRACT A recombinant clone expressing an immunoreactive antigen ofBartonella bacilliformis was isolated by screening a genomic DNA library with serum from a patient with the chronic verruga phase of bartonellosis. The clone, pBIPIM-17, contained a partial open reading frame that expressed an immunoreactive fusion protein. Subsequent rescreening of the library by plaque hybridization resulted in the isolation of recombinant clones that contain the entire open reading frame. The open reading frame (ORF-401) is capable of encoding a protein of 401 amino acids with a predicted molecular mass of 43 kDa. The deduced amino acid sequence of the encoded protein was found to be highly homologous to a recently identified bacterial lipoprotein (LppB/NlpD) which has been associated with virulence. Evidence has been provided to show that the 43-kDa antigen of B. bacilliformis is a lipoprotein and that it is likely to use the same biosynthetic pathway as other bacterial lipoproteins. This is the first report to date that characterizes a lipoprotein of B. bacilliformis. The immunogenicity of the B. bacilliformis LppB homologue was demonstrated by Western blot analysis using sera from patients with clinical bartonellosis. Sera from patients who had a high titer forBartonella henselae, the causative agent of bacillary angiomatosis and cat scratch disease, also recognized the recombinant 43-kDa antigen, suggesting that a homologue of this antigen is present in B. henselae. Using a cocktail of synthetic peptides corresponding to predicted major antigenic sites, polyclonal antiserum specific for the LppB homologue of B. bacilliformis was generated. This antiserum did not recognize the NlpD homologue of Escherichia coli or the 43-kDa antigen ofB. henselae.

scholarly journals MOLECULAR CHARACTERIZATION AND SEQUENCE PHYLOGENETIC ANALYSIS OF SURFACE ANTIGEN 3 (SAG3) GENE OF LOCAL INDIAN ISOLATES (CHENNAI AND IZATNAGAR) OF Toxoplasma gondii

2015 ◽  
Vol 57 (3) ◽  
pp. 205-209 ◽  
Author(s):  
Vikrant SUDAN ◽  
Anup Kumar TEWARI ◽  
Harkirat SINGH
Keyword(s):  
Toxoplasma Gondii ◽  
Molecular Characterization ◽  
Surface Antigen ◽  
Point Of View ◽  
Comparison Analysis ◽  
Present Communication ◽  
Reading Frame ◽  
Indian Isolates ◽  
Entire Open Reading Frame

Context and objective: The molecular characterization of local isolates of Toxoplasma gondii is considered significant so as to assess the homologous variations between the different loci of various strains of parasites. Design and setting: The present communication deals with the molecular cloning and sequence analysis of the 1158 bp entire open reading frame (ORF) of surface antigen 3 (SAG3) of two Indian T. gondii isolates (Chennai and Izatnagar) being maintained as cryostock at the IVRI. Method: The surface antigen 3 (SAG3) of two local Indian isolates were cloned and sequenced before being compared with the available published sequences. Results: The sequence comparison analysis revealed 99.9% homology with the standard published RH strain sequence of T. gondii. The strains were also compared with other established published sequences and found to be most related to the P-Br strain and CEP strain (both 99.3%), and least with PRU strain (98.4%). However, the two Indian isolates had 100% homology between them. Conclusion: Finally, it was concluded that the Indian isolates were closer to the RH strain than to the P-Br strain (Brazilian strain), the CEP strain and the PRU strains (USA), with respect to nucleotide homology. The two Indian isolates used in the present study are known to vary between themselves, as far as homologies related to other genes are concerned, but they were found to be 100% homologous as far as SAG3 locus is concerned. This could be attributed to the fact that this SAG3 might be a conserved locus and thereby, further detailed studies are thereby warranted to exploit the use of this particular molecule in diagnostics and immunoprophylactics. The findings are important from the point of view of molecular phylogeny.

scholarly journals Discovery of a 382-nt deletion during the early evolution of SARS-CoV-2

2020 ◽  
Author(s):  
Yvonne CF Su ◽  
Danielle E Anderson ◽  
Barnaby E Young ◽  
Feng Zhu ◽  
Martin Linster ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Human Population ◽  
Host Adaptation ◽  
Open Reading Frame ◽  
N Gene ◽  
Regulatory Sequence ◽  
Reading Frame ◽  
Replicative Fitness ◽  
Similar Variation ◽  
Entire Open Reading Frame

To date, the SARS-CoV-2 genome has been considered genetically more stable than SARS-CoV or MERS-CoV. Here we report a 382-nt deletion covering almost the entire open reading frame 8 (ORF8) of SARS-CoV-2 obtained from eight hospitalized patients in Singapore. The deletion also removes the ORF8 transcription-regulatory sequence (TRS), which in turn enhances the downstream transcription of the N gene. We also found that viruses with the deletion have been circulating for at least four weeks. During the SARS-CoV outbreak in 2003, a number of genetic variants were observed in the human population [1], and similar variation has since been observed across SARS-related CoVs in humans and bats. Overwhelmingly these viruses had mutations or deletions in ORF8, that have been associated with reduced replicative fitness of the virus [2]. This is also consistent with the observation that towards the end of the outbreak sequences obtained from human SARS cases possessed an ORF8 deletion that may be associated with host adaptation [1]. We therefore hypothesise that the major deletion revealed in this study may lead to an attenuated phenotype of SARS-CoV-2.

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