scholarly journals Sortases, Surface Proteins, and Their Roles in Staphylococcus aureus Disease and Vaccine Development

2019 ◽  
pp. 173-188 ◽  
Author(s):  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
Staphylococcus Aureus ◽  
Vaccine Development ◽  
Surface Proteins

scholarly journals CD4 T Cell Antigens from Staphylococcus aureus Newman Strain Identified following Immunization with Heat-Killed Bacteria

2012 ◽  
Vol 19 (4) ◽  
pp. 477-489 ◽  
Author(s):  
Paulraj K. Lawrence ◽  
Bachra Rokbi ◽  
Nadège Arnaud-Barbe ◽  
Eric L. Sutten ◽  
Junzo Norimine ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
T Cell ◽  
Reverse Genetics ◽  
Vaccine Development ◽  
Protein A ◽  
Cd4 T Cell ◽  
Content Type ◽  
Intramammary Infections ◽  
T Cell Antigens ◽  
Ifn Γ

ABSTRACTStaphylococcus aureusis a commensal bacterium associated with the skin and mucosal surfaces of humans and animals that can also cause chronic infection. The emergence of antibiotic-resistant strains such as methicillin-resistantS. aureus(MRSA) and strains causing chronic intramammary infections (IMI) in cows results in severe human and livestock infections. Conventional approaches to vaccine development have yielded only a few noneffective vaccines against MRSA or IMI strains, so there is a need for improved vaccine development. CD4 T lymphocytes are required for promoting gamma interferon (IFN-γ) mediated immunoglobulin isotype switching in B lymphocytes to produce high-affinity IgG antibodies and IFN-γ-mediated phagocyte activation for an effective resolution of bacterial infection. However, the lack of known CD4 T cell antigens fromS. aureushas made it difficult to design effective vaccines. The goal of this study was to identifyS. aureusproteins recognized by immune CD4 T cells. Using a reverse genetics approach, 43 antigens were selected from theS. aureusNewman strain. These included lipoproteins, proteases, transcription regulators, an alkaline shock protein, conserved-domain proteins, hemolysins, fibrinogen-binding protein, staphylokinase, exotoxin, enterotoxin, sortase, and protein A. Screening of expressed proteins for recall T cell responses in outbred, immune calves identified 13 proteins that share over 80% sequence identity among MRSA or IMI strains. These may be useful for inclusion in a broadly protective multiantigen vaccine against MRSA or IMI.

scholarly journals Application of Median Lethal Concentration (LC50) of Pathogenic Microorganisms and Their Antigens in Vaccine Development

2020 ◽  
Author(s):  
Saganuwan Alhaji Saganuwan
Keyword(s):  
Staphylococcus Aureus ◽  
Disease Virus ◽  
Vaccine Development ◽  
Hepatitis A Virus ◽  
Lethal Dose ◽  
Vaccine Dose ◽  
Foot And Mouth Disease ◽  
Bacterial Colony ◽  
Mouth Disease Virus

Abstract Objective: Lack of ideal mathematical models to qualify and quantify both pathogenicity, and virulence is a dreadful setback in development of new antimicrobials and vaccines against resistance pathogenic microorganisms.Hence, the modified arithmetical formula of Reed and Muenchhas been integrated with other formulas and used to determine bacterial colony forming unit/ viral concentration, virulence and immunogenicity from LC50s established in the laboratories. Results: Microorganisms’antigens tested are Staphylococcus aureus, Streptococcuspneumonia, Pseudomonas aeruginosa in mice and rat, Edwardsiellaictaluri, Aeromonashydrophila, Aeromonasveronii in fish, New Castle Disease virus in chicken, Sheep Pox Virus, Foot-and-Mouth Disease Virus and Hepatitis A virus in vitro, respectively. The LC50s for the pathogens using different routes of administrations are 1.93 x 103(sheep poxvirus) and 1.75 x 1010 for Staphylococcus aureus (ATCC29213) in rat respectively. Titre index (TI) equals N log10 LC50 and provides protection against lethal dose in graded fashion which translates to protection index. N is the number of vaccine dose that could neutralize the LC50. Hence, parasite inoculum of 103 to 1011could be used as basis for determination of median lethal dose(LD50), LC50 and median bacterial concentrations (BC50)determination, pathogenic dose for immune stimulation should be sought at concentrations less than LC10.

scholarly journals Determination of Median Lethal Concentrations (Lc50) of Pathogenic Antigens and Their Applications in Vaccine Development

2020 ◽  
Author(s):  
Saganuwan Alhaji Saganuwan
Keyword(s):  
Staphylococcus Aureus ◽  
Disease Virus ◽  
Vaccine Development ◽  
Hepatitis A Virus ◽  
Lethal Dose ◽  
Vaccine Dose ◽  
Foot And Mouth Disease ◽  
Mouth Disease Virus

Abstract Objective: Lack of ideal mathematical models to qualify and quantify both pathogenicity, and virulence is a dreadful setback in development of new antimicrobials and vaccines against resistance pathogenic microorganisms. Hence, the modified arithmetical formula of Reed and Muench has been integrated with other formulas and used for determination of antigen concentration and parasites inoculums that would kill 50% of test animals (LC50).Results: Microorganisms’ antigens tested are Staphylococcus aureus, Streptococcus pneumonia, Pseudomonas aeruginosa in mice and rat, Edwardsiella ictaluri, Aeromonas hydrophila, Aeromonas veronii in fish, New Castle Disease virus in chicken, Sheep Pox Virus, Foot-and-Mouth Disease Virus and Hepatitis A virus in vitro, respectively. The LC50s for the pathogens using different routes of administrations are 1.93 x 103 (sheep poxvirus) and 1.75 x 1010 for Staphylococcus aureus (ATCC29213) in rat respectively. N is the number of vaccine dose that could neutralize the LC50.Titre index (TI) equals N log10 LC50 and provides protection against lethal dose in graded fashion which translates to protection index. Hence, parasite inoculum of 103 to 1011 could be used as basis for median lethal dose (LD50), LC50 and median bacterial concentrations (BC50) determination, pathogenic dose for immune stimulation should be sought at concentrations less than LC10.

scholarly journals A genomic and proteomic analysis of surface proteins in bovine-adapted lineages of Staphylococcus aureus

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Shauna D. Drumm ◽  
Rebecca Owens ◽  
Jennifer Mitchell ◽  
Orla M. Keane
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Surface Proteins ◽  
Host Cells ◽  
Mass Spectrometry Analysis ◽  
In Vitro Assays ◽  
Immune Recognition ◽  
Independent Manner ◽  
Genes Encoding

In Ireland, Staphylococcus aureus is the most common cause of intramammary infection (IMI) in cattle with the bovine-adapted lineages CC151 and CC97 most commonly found. Surface proteins play a major role in establishing and maintaining the infection. A previous study revealed that a strain from the CC151 lineage showed significant decay in genes encoding predicted surface proteins. Twenty-three S. aureus strains, twelve belonging to CC151 and eleven belonging to CC97, isolated from clinical IMI, were sequenced and genes encoding cell wall anchored (CWA) proteins predicted. Analysis showed that a minority of genes encoding putative CWA proteins were intact in the CC151 strains compared to CC97. Of the 26 known CWA proteins in S. aureus, the CC151 strains only encoded 10 intact genes while CC97 encoded on average 18 genes. Also within the CC97 lineage, the repertoire of genes varied depending on individual strains, with strains encoding between 17-20 intact genes. Although CC151 is reported to internalize within bovine host cells, it does so in a fibronectin-binding protein (FnBPA and FnBPB) independent manner. In-vitro assays were performed and results showed that strains from CC151, and surprisingly also CC97, weakly bound bovine fibronectin and that the FnBPs were poorly expressed in both these lineages. Mass spectrometry analysis of cell wall extracts revealed that SdrE and AdsA were the most highly expressed CWA proteins in both lineages. These results demonstrate significant differences between CC151 and CC97 in their repertoire of genes encoding CWA proteins, which may impact immune recognition of these strains and their interactions with host cells.

scholarly journals Vaccine composition formulated with a novel TLR7-dependent adjuvant induces high and broad protection against Staphylococcus aureus

2015 ◽  
Vol 112 (12) ◽  
pp. 3680-3685 ◽  
Author(s):  
Fabio Bagnoli ◽  
Maria Rita Fontana ◽  
Elisabetta Soldaini ◽  
Ravi P. N. Mishra ◽  
Luigi Fiaschi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Passive Immunization ◽  
Surface Proteins ◽  
Antibody Isotype ◽  
Low Frequencies ◽  
Functional Activities ◽  
Immunization Strategies ◽  
Antibody Titers ◽  
Combined Vaccine ◽  
New Formulation

Both active and passive immunization strategies against Staphylococcus aureus have thus far failed to show efficacy in humans. With the attempt to develop an effective S. aureus vaccine, we selected five conserved antigens known to have different roles in S. aureus pathogenesis. They include the secreted factors α-hemolysin (Hla), ess extracellular A (EsxA), and ess extracellular B (EsxB) and the two surface proteins ferric hydroxamate uptake D2 and conserved staphylococcal antigen 1A. The combined vaccine antigens formulated with aluminum hydroxide induced antibodies with opsonophagocytic and functional activities and provided consistent protection in four mouse models when challenged with a panel of epidemiologically relevant S. aureus strains. The importance of antibodies in protection was demonstrated by passive transfer experiments. Furthermore, when formulated with a toll-like receptor 7-dependent (TLR7) agonist recently designed and developed in our laboratories (SMIP.7–10) adsorbed to alum, the five antigens provided close to 100% protection against four different staphylococcal strains. The new formulation induced not only high antibody titers but also a Th1 skewed immune response as judged by antibody isotype and cytokine profiles. In addition, low frequencies of IL-17–secreting T cells were also observed. Altogether, our data demonstrate that the rational selection of mixtures of conserved antigens combined with Th1/Th17 adjuvants can lead to promising vaccine formulations against S. aureus.

Covalent Sortase A Inhibitor ML346 Prevents Staphylococcus aureus Infection of Galleria mellonella

2021 ◽  
Author(s):  
Xiang-Na Guan ◽  
Tao Zhang ◽  
Teng Yang ◽  
Ze Dong ◽  
Song Yang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Galleria Mellonella ◽  
Surface Proteins ◽  
Sortase A ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Aureus Infection ◽  
Cell Wall Peptidoglycan

The housekeeping sortase A (SrtA), a membrane-associated cysteine transpeptidase, is responsible for anchoring surface proteins to the cell wall peptidoglycan in Gram-positive bacteria. This process is essential for the regulation...

scholarly journals The iron-regulated surface determinant B (IsdB) protein from Staphylococcus aureus acts as a receptor for the host protein vitronectin

2020 ◽  
Vol 295 (29) ◽  
pp. 10008-10022 ◽  
Author(s):  
Giampiero Pietrocola ◽  
Angelica Pellegrini ◽  
Mariangela J. Alfeo ◽  
Loredana Marchese ◽  
Timothy J. Foster ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Matrix ◽  
Matrix Protein ◽  
Wide Spectrum ◽  
Surface Proteins ◽  
Host Protein ◽  
Extracellular Matrix Protein ◽  
Bacterial Cells ◽  
Iron Starvation ◽  
Extracellular Matrix Components

Staphylococcus aureus is an important bacterial pathogen that can cause a wide spectrum of diseases in humans and other animals. S. aureus expresses a variety of virulence factors that promote infection with this pathogen. These include cell-surface proteins that mediate adherence of the bacterial cells to host extracellular matrix components, such as fibronectin and fibrinogen. Here, using immunoblotting, ELISA, and surface plasmon resonance analysis, we report that the iron-regulated surface determinant B (IsdB) protein, besides being involved in heme transport, plays a novel role as a receptor for the plasma and extracellular matrix protein vitronectin (Vn). Vn-binding activity was expressed by staphylococcal strains grown under iron starvation conditions when Isd proteins are expressed. Recombinant IsdB bound Vn dose dependently and specifically. Both near-iron transporter motifs NEAT1 and NEAT2 of IsdB individually bound Vn in a saturable manner, with KD values in the range of 16–18 nm. Binding of Vn to IsdB was specifically blocked by heparin and reduced at high ionic strength. Furthermore, IsdB-expressing bacterial cells bound significantly higher amounts of Vn from human plasma than did an isdB mutant. Adherence to and invasion of epithelial and endothelial cells by IsdB-expressing S. aureus cells was promoted by Vn, and an αvβ3 integrin-blocking mAb or cilengitide inhibited adherence and invasion by staphylococci, suggesting that Vn acts as a bridge between IsdB and host αvβ3 integrin.

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