scholarly journals Genetic Immunization with the Region Encoding the α-Helical Domain of PspA Elicits Protective Immunity againstStreptococcus pneumoniae

2001 ◽  
Vol 69 (9) ◽  
pp. 5456-5463 ◽  
Author(s):  
Joseph R. Bosarge ◽  
James M. Watt ◽  
D. Olga McDaniel ◽  
Edwin Swiatlo ◽  
Larry S. McDaniel
Keyword(s):  
Protein A ◽  
Survival Rates ◽  
Serum Antibody ◽  
Pneumococcal Infection ◽  
Surface Protein ◽  
Eukaryotic Expression ◽  
Dependent Manner ◽  
Genetic Immunization ◽  
Helical Domain ◽  
Dose Dependent

ABSTRACT Pneumococcal surface protein A (PspA) is a pneumococcal virulence factor capable of eliciting protection against pneumococcal infection in mice. Previous studies have demonstrated that the protection is antibody mediated. Here we examined the ability ofpspA to elicit a protective immune response following genetic immunization of mice. Mice were immunized by intramuscular injections with a eukaryotic expression vector encoding the α-helical domain of PspA/Rx1. Immunization induced a PspA-specific serum antibody response, and immunized mice survived pneumococcal challenge. Survival and antibody responses occurred in a dose-dependent manner, the highest survival rates being seen with doses of 10 μg or greater. The ability of genetic immunization to elicit cross-protection was demonstrated by the survival of immunized mice challenged with pneumococcal strains differing in capsule and PspA types. Also, immunized mice were protected from intravenous and intratracheal challenges with pneumococci. Similar to the results seen with immunization with PspA, the survival of mice genetically immunized with pspA was antibody mediated. There was no decline in the level of protection 7 months after immunization. These results support the use of genetic immunization to elicit protective immune responses against extracellular pathogens.

scholarly journals Gene therapy via canalostomy approach preserves auditory and vestibular functions in a mouse model of Jervell and Lange-Nielsen syndrome type 2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuewen Wu ◽  
Li Zhang ◽  
Yihui Li ◽  
Wenjuan Zhang ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Mouse Model ◽  
Inner Ear ◽  
Viral Vectors ◽  
Survival Rates ◽  
Semicircular Canals ◽  
Dependent Manner ◽  
Syndrome Type ◽  
Dose Dependent

AbstractMutations in voltage-gated potassium channel KCNE1 cause Jervell and Lange-Nielsen syndrome type 2 (JLNS2), resulting in congenital deafness and vestibular dysfunction. We conducted gene therapy by injecting viral vectors using the canalostomy approach in Kcne1−/− mice to treat both the hearing and vestibular symptoms. Results showed early treatment prevented collapse of the Reissner’s membrane and vestibular wall, retained the normal size of the semicircular canals, and prevented the degeneration of inner ear cells. In a dose-dependent manner, the treatment preserved auditory (16 out of 20 mice) and vestibular (20/20) functions in mice treated with the high-dosage for at least five months. In the low-dosage group, a subgroup of mice (13/20) showed improvements only in the vestibular functions. Results supported that highly efficient transduction is one of the key factors for achieving the efficacy and maintaining the long-term therapeutic effect. Secondary outcomes of treatment included improved birth and litter survival rates. Our results demonstrated that gene therapy via the canalostomy approach, which has been considered to be one of the more feasible delivery methods for human inner ear gene therapy, preserved auditory and vestibular functions in a dose-dependent manner in a mouse model of JLNS2.

scholarly journals Differential PsaA-, PspA-, PspC-, and PdB-Specific Immune Responses in a Mouse Model of Pneumococcal Carriage

2005 ◽  
Vol 73 (2) ◽  
pp. 1006-1013 ◽  
Author(s):  
Ravichandran Palaniappan ◽  
Shailesh Singh ◽  
Udai P. Singh ◽  
Senthil Kumar K. Sakthivel ◽  
Edwin W. Ades ◽  
...  
Keyword(s):  
Mouse Model ◽  
Protein A ◽  
Serum Antibody ◽  
Surface Protein ◽  
Interleukin 4 ◽  
Necrosis Factor Alpha ◽  
Cervical Lymph Nodes ◽  
Pneumococcal Carriage ◽  
Macrophage Colony ◽  
Antibody Levels

ABSTRACT Larger numbers of pneumococci were detected in the nasal tract compared to the lung, cervical lymph nodes, and spleen 1, 2, 4, 7, 14, and 21 days after nasal challenge with Streptococcus pneumoniae strain EF3030. In this mouse model of pneumococcal carriage, peripheral S. pneumoniae pneumococcal surface adhesin A (PsaA)-specific humoral responses (immunoglobulin G2a [IgG2a] ≫ IgG1 = IgG2b > IgG3) were significantly higher than pneumococcal surface protein A (PspA)-specific, genetic toxoid derivative of pneumolysin (PdB)-specific, or pneumococcal surface protein C (PspC)-specific serum antibody levels. However, PspA-specific mucosal IgA antibody levels were significantly higher than those against PsaA, PdB, and PspC. In general, both PsaA- and PspA-specific lung-, cervical lymph node-, nasal tract-, and spleen-derived CD4+ T-cell cytokine (interleukin-4, interleukin-6, granulocyte-macrophage colony-stimulating factor, gamma interferon, and tumor necrosis factor alpha) and proliferative responses were higher than those for either PspC or PdB. Taken together, these findings suggest that PsaA- and PspA-specific mucosal responses as well as systemic humoral and T helper cell cytokine responses are predominantly yet differentially induced during pneumococcal carriage.

Ketamine Inhibits Monoamine Transporters Expressed in Human Embryonic Kidney 293 Cells 

1998 ◽  
Vol 88 (3) ◽  
pp. 768-774 ◽  
Author(s):  
Mitsuhiro Nishimura ◽  
Kohji Sato ◽  
Tomoya Okada ◽  
Ikuto Yoshiya ◽  
Patrick Schloss ◽  
...  
Keyword(s):  
Eukaryotic Expression ◽  
Psychotic Symptoms ◽  
Kidney Cells ◽  
Dependent Manner ◽  
Monoamine Transporters ◽  
Human Embryonic Kidney ◽  
General Anesthetic ◽  
Serotonin Transporters ◽  
Human Embryonic Kidney Cells ◽  
Dose Dependent

Background Ketamine has been characterized as having psychotomimetic and sympathomimetic effects. These symptoms have raised the possibility that ketamine affects monoaminergic neurotransmission. To elucidate the relation between ketamine and monoamine transporters, the authors constructed three cell lines that stably express the norepinephrine, dopamine, and serotonin transporters and investigated the effects of ketamine on these transporters. Methods Human embryonic kidney cells were transfected using the Chen-Okayama method with the human norepinephrine, rat dopamine, and rat serotonin transporter cDNA subcloned into the eukaryotic expression vector. Using cells stably expressing these transporters, the authors investigated the effects of ketamine on the uptake of these compounds and compared them with those of pentobarbital. Results Inhibition analysis showed that ketamine significantly inhibited the uptake of all three monoamine transporters in a dose-dependent manner. The Ki (inhibition constant) values of ketamine on the norepinephrine, dopamine, and serotonin transporters were 66.8 microM, 62.9 microM, and 162 microM, respectively. Pentobarbital, a typical general anesthetic agent with no psychotic symptoms, did not affect the uptake of monoamines, however. Further, neither the glycine transporter 1 nor the glutamate/aspartate transporter was affected by ketamine, indicating that ketamine preferentially inhibits monoamine transporters. Conclusions Ketamine inhibited monoamine transporters expressed in human embryonic kidney cells in a dose-dependent manner. This result suggests that the ketamine-induced inhibition of monoamine transporters might contribute to its psychotomimetic and sympathomimetic effects through potentiating monoaminergic neurotransmission.

scholarly journals Subinhibitory Concentrations of Linezolid Reduce Staphylococcus aureus Virulence Factor Expression

2004 ◽  
Vol 48 (2) ◽  
pp. 546-555 ◽  
Author(s):  
Katussevani Bernardo ◽  
Norbert Pakulat ◽  
Silke Fleer ◽  
Annabelle Schnaith ◽  
Olaf Utermöhlen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein A ◽  
Sodium Dodecyl ◽  
Elongation Factor ◽  
Dependent Manner ◽  
Triacylglycerol Lipase ◽  
Subinhibitory Concentrations ◽  
Dose Dependent

ABSTRACT The influence of the antibiotic linezolid on the secretion of exotoxins by Staphylococcus aureus was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot analysis. S. aureus suspensions were treated with grading subinhibitory concentrations of linezolid (12.5, 25, 50, and 90% of MIC) at different stages of bacterial growth (i.e., an optical density at 540 nm [OD540] of 0.05 or 0.8). When added to S. aureus cultures at an OD540 of 0.05, linezolid reduced in a dose-dependent manner the secretion of specific virulence factors, including staphylococcal enterotoxin A (SEA) and SEB, bifunctional autolysin, autolysin, protein A, and alpha- and beta-hemolysins. In contrast, other presumably nontoxic exoproteins remained unchanged or even accumulated in supernatants in the presence of linezolid at a 90% MIC. Similarily, when added at OD540 of 0.8, that is, after quorum sensing, linezolid reduced the release of virulence factors, whereas the relative abundance of nontoxic exoproteins such as triacylglycerol lipase, glycerol ester hydrolase, DnaK, or translation elongation factor EF-Tu was found to be increased. Consistently, linezolid reduced in a dose-dependent manner the tumor necrosis factor-inducing activity secreted by S. aureus into the culture supernatants. The results of our study suggest that the expression of virulence factors in S. aureus is especially sensitive to the inhibition of protein synthesis by linezolid, which should be an advantage in the treatment of infections with toxin-producing S. aureus.

scholarly journals Broadly reactive human monoclonal antibodies targeting the pneumococcal histidine triad protein protect against fatal pneumococcal infection

2021 ◽  
Author(s):  
Jiachen Huang ◽  
Aaron D. Gingerich ◽  
Fredejah Royer ◽  
Amy V. Paschall ◽  
Alma Pena-Briseno ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Disease Prevention ◽  
Disease Incidence ◽  
Protein A ◽  
Pneumococcal Infection ◽  
Surface Protein ◽  
Human Monoclonal Antibodies ◽  
Human Mabs ◽  
Prevention And Treatment ◽  
Pneumococcal Serotype

AbstractStreptococcus pneumoniae remains a leading cause of bacterial pneumonia despite the widespread use of vaccines. While vaccines are effective at reducing the incidence of most vaccine-included serotypes, a rise in infection due to non-vaccine serotypes, and moderate efficacy against some vaccine included serotypes have contributed to high disease incidence. Additionally, numerous isolates of S. pneumoniae are antibiotic or multi-drug resistant. Several conserved pneumococcal proteins prevalent in the majority of serotypes have been examined as vaccines in preclinical and clinical trials. An additional, yet unexplored tool for disease prevention and treatment is the use of human monoclonal antibodies (mAbs) targeting conserved pneumococcal proteins. Here, we isolate the first human mAbs (PhtD3, PhtD6, PhtD7, PhtD8, PspA16) against the pneumococcal histidine triad protein (PhtD), and the pneumococcal surface protein A (PspA), two conserved and protective antigens. mAbs to PhtD target diverse epitopes on PhtD, and mAb PspA16 targets the N-terminal segment of PspA. The PhtD-specific mAbs bind to multiple serotypes, while mAb PspA16 serotype breadth is limited. mAbs PhtD3 and PhtD8 prolong the survival of mice infected with pneumococcal serotype 3. Furthermore, mAb PhtD3 prolongs the survival of mice in intranasal and intravenous infection models with pneumococcal serotype 4, and in mice infected with pneumococcal serotype 3 when administered 24 hours after pneumococcal infection. All PhtD and PspA mAbs demonstrate opsonophagocytic activity, suggesting a potential mechanism of protection. Our results provide new human mAbs for pneumococcal disease prevention and treatment, and identify epitopes on PhtD and PspA recognized by human B cells.

scholarly journals Regions of PspA/EF3296 Best Able To Elicit Protection against Streptococcus pneumoniae in a Murine Infection Model

2003 ◽  
Vol 71 (3) ◽  
pp. 1033-1041 ◽  
Author(s):  
Hazeline Roche ◽  
Anders Håkansson ◽  
Susan K. Hollingshead ◽  
David E. Briles
Keyword(s):  
Amino Acids ◽  
Streptococcus Pneumoniae ◽  
Protein A ◽  
Surface Protein ◽  
Cross Protection ◽  
Infection Model ◽  
Helical Domain ◽  
Protective Antibodies ◽  
Terminal Amino ◽  
Helical Region

ABSTRACT Pneumococcal surface protein A (PspA) can elicit protection against Streptococcus pneumoniae in mouse infection models. PspA is classified by serology and amino acid sequence into two major families that are divided by sequence into five clades. The most variable portion of the molecule is the α-helical domain, which comprises the N-terminal half of PspA. Prior studies of a family 1 PspA protein observed that protective antibodies are reactive with epitopes in the α-helical domain and that most cross-protective epitopes mapped to the 108 most C-terminal amino acids of the α-helical region. In these studies, we have used six overlapping recombinant fragments of family 2, clade 3 PspA/EF3296 to map the protection-eliciting regions of its α-helical domain. The three fragments, which included the 104 most C-terminal amino acids of the α-helical domain (314 to 418), could each elicit protection against EF3296. A fragment comprising amino acids 75 to 305 failed to elicit significant protection. A fragment containing amino acids 1 to 115 elicited protection against EF3296 in BALB/c mice but not in CBA/N mice. All three fragments containing amino acids 314 to 418 were able to elicit cross-protection against pneumococci expressing PspA proteins of clades 2, 3, 4, and 5. Cross-protection elicited by these three fragments was easier to demonstrate in CBA/N mice than in BALB/c mice. The 1-to-115 fragment, however, elicited some cross-protection against clades 2 and 4 in BALB/c mice but not in CBA/N mice. These studies provide support for the importance of the C-terminal 104 and N-terminal 115 amino acids of the α-helical region of PspA in the elicitation of cross-protection.

scholarly journals The Proline-Rich Region of Pneumococcal Surface Proteins A and C Contains Surface-Accessible Epitopes Common to All Pneumococci and Elicits Antibody-Mediated Protection against Sepsis

2010 ◽  
Vol 78 (5) ◽  
pp. 2163-2172 ◽  
Author(s):  
Calvin C. Daniels ◽  
Patricia Coan ◽  
Janice King ◽  
Joanetha Hale ◽  
Kimberly A. Benton ◽  
...  
Keyword(s):  
Protein A ◽  
Pneumococcal Infection ◽  
Passive Immunization ◽  
Surface Protein ◽  
Helical Structure ◽  
Structural Similarity ◽  
Cross Reactivity ◽  
Surface Proteins ◽  
Structure Characteristic ◽  
Protective Antibodies

ABSTRACTPneumococcal surface protein A (PspA) and PspC ofStreptococcus pneumoniaeare surface virulence proteins that interfere with complement deposition and elicit protective immune responses. The C-terminal halves of PspA and PspC have some structural similarity and contain highly cross-reactive proline-rich (PR) regions. In many PR regions of PspA and PspC, there exists an almost invariant nonproline block (NPB) of about 33 amino acids. Neither the PR regions nor their NPB exhibit the alpha-helical structure characteristic of much of the protection-eliciting N-terminal portions of PspA and PspC. Prior studies of PspA and PspC as immunogens focused primarily on the alpha-helical regions of these molecules that lack the PR and NPB regions. This report shows that immunization with recombinant PR (rPR) molecules and passive immunization with monoclonal antibodies reactive with either NPB or PR epitopes are protective against infection in mice. PR regions of both PspA and PspC were antibody accessible on the pneumococcal surface. Our results indicate that while PspA could serve as a target of these protective antibodies in invasive infections, PspC might not. When antibody responses to rPR immunogens were evaluated by using flow cytometry to measure antibody binding to live pneumococci, it was observed that the mice that survived subsequent challenge produced significantly higher levels of antibodies reactive with exposed PR epitopes than the mice that became moribund. Due to their conservation and cross-reactivity, the PR regions and NPB regions represent potential vaccine targets capable of eliciting cross-protection immunity against pneumococcal infection.

scholarly journals An Amino Acids Mixture Improves the Hepatotoxicity Induced by Acetaminophen in Mice

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Francesco Di Pierro ◽  
Giuseppe Rossoni
Keyword(s):  
Survival Rates ◽  
Weight Ratio ◽  
Liver Weight ◽  
Protective Role ◽  
High Dose ◽  
Dependent Manner ◽  
Total Glutathione ◽  
Dose Dependent ◽  
Better Than

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug, but at high dose it leads to undesirable side effects, such as hepatotoxicity and nephrotoxicity. The aim of this study was to evaluate the protective role of DDM-GSH, a mixture of L-cysteine, L-methionine, and L-serine in a weight ratio of 2 : 1 : 1, in comparison to N-acetylcysteine (NAC), against acetaminophen- (APAP-) induced hepatotoxicity in mice. Toxicity was induced in mice by the intraperitoneal (ip) administration of low dose (2 mmol/kg) or high dose (8 mmol/kg) of APAP. DDM-GSH (0.4 to 1.6 mmol/kg) was given ip to mice 1 h before the APAP administration. The same was done with NAC (0.9 to 3.6 mmol/kg), the standard antidote of APAP toxicity. Mice were sacrificed 8 h after the APAP injection to determine liver weight, serum alanine aminotransferase (ALT), and total glutathione (GSH) depletion and malondialdehyde (MDA) accumulation in liver tissues. DDM-GSH improved mouse survival rates better than NAC against a high dose of APAP. Moreover, DDM-GSH significantly reduced in a dose-dependent manner not only APAP-induced increases of ALT but also APAP-induced hepatic GSH depletion and MDA accumulation. Our results suggest that DDM-GSH may be more potent than NAC in protecting the liver from APAP-induced liver injury.

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