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MSCRAMM
MSCRAMM (acronym for "microbial surface components recognizing adhesive matrix molecules") adhesin proteins mediate the initial attachment of bacteria to host tissue, providing a critical step to establish infection. Examples include protein A, clumping factor A (ClfA), fibronectin binding protein A (FnbpA) from ''Staphylococcus aureus'', SdrG from ''Staphylococcus epidermidis'', M protein from ''Streptococcus pyogenes'', and protein G in other ''Streptococcus'' species. All of these MSCRAMMs bind to fibrinogen except protein A, that binds IgG, but also other targets for MSCRAMMs are known, such as fibronectin. Protein M binds to the Fc region of certain antibodies. The MSCRAMMs have mainly been studied in Gram positive pathogens and are promising drug targets. The monoclonal antibody tefibazumab Tefibazumab (named Aurexis but not approved) is a humanized monoclonal antibody for the treatment of severe infections with '' Staphylococcus aureus''. Possible indications include t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tefibazumab
Tefibazumab (named Aurexis but not approved) is a humanized monoclonal antibody for the treatment of severe infections with '' Staphylococcus aureus''. Possible indications include the treatment of ''S. aureus'' in a phase 2a patients with cystic fibrosis and of methicillin-resistant ''S. aureus''. It was developed by Inhibitex. See also * MSCRAMM MSCRAMM (acronym for "microbial surface components recognizing adhesive matrix molecules") adhesin proteins mediate the initial attachment of bacteria to host tissue, providing a critical step to establish infection. Examples include protein A, cl ... (microbial surface components recognizing adhesive matrix molecules) References Monoclonal antibodies Experimental drugs {{monoclonal-antibody-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibronectin Binding Protein A
Fibronectin binding protein A (FnBPA) is a ''Staphylococcus aureus'' MSCRAMM cell surface-bound protein that binds to both fibronectin and fibrinogen. It is an Bacterial adhesin, adhesin which enables ''Staphylococcus aureus'' (''S. aureus'') to adhere to host cells of another organism, and an invasin facilitating its internalisation into these cells. This is true over a range of different cell types. The FnBP alone is capable of providing this invasive property, without the requirement of co-receptors. Even FnBP coated beads have been shown to become internalised into cells ''S. aureus'' is able to bind to host cells in the absence of the FnBP, but its adherence and invasive properties are much reduced (up to a 500-fold decrease in number of internalised cells) Structure The FnBP inserts into the cell wall of ''S. aureus'' by means of a C-terminal LPXTG anchor. Two fibronectin binding domains have been identified - one is present in the C-terminal D repeat region, and one in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein A
Protein A is a 42 kDa surface protein originally found in the cell wall of the bacteria ''Staphylococcus aureus''. It is encoded by the ''spa'' gene and its regulation is controlled by DNA topology, cellular osmolarity, and a two-component system called ArlS-ArlR. It has found use in biochemical research because of its ability to bind immunoglobulins. It is composed of five homologous Ig-binding domains that fold into a three-helix bundle. Each domain is able to bind proteins from many mammalian species, most notably IgGs. It binds the heavy chain within the Fc region of most immunoglobulins and also within the Fab region in the case of the human VH3 family. Through these interactions in serum, where IgG molecules are bound in the wrong orientation (in relation to normal antibody function), the bacteria disrupts opsonization and phagocytosis. History As a by-product of his work on type-specific staphylococcus antigens, Verwey reported in 1940 that a protein fraction prepared from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clumping Factor A
Clumping factor A, or ClfA, is a virulence factor from ''Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...'' (''S. aureus'') that binds to fibrinogen. ClfA also has been shown to bind to complement regulator I protein. It is responsible for the clumping of blood plasma observed when adding ''S. aureus'' to human plasma. Clumping factor can be detected by the Coagulase#Slide test, slide test. See also * Tefibazumab * Coagulase References Staphylococcaceae Bacterial proteins Virulence factors {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staphylococcus Aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although ''S. aureus'' usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. ''S. aureus'' is one of the leading pathogens for deaths associated with antimicrobial resistance and the emergence of antibiotic-resistant strains, such as methicillin-resistant ''S. aureus'' (MRSA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staphylococcus Epidermidis
''Staphylococcus epidermidis'' is a Gram-positive bacterium, and one of over 40 species belonging to the genus '' Staphylococcus''. It is part of the normal human microbiota, typically the skin microbiota, and less commonly the mucosal microbiota and also found in marine sponges. It is a facultative anaerobic bacteria. Although ''S. epidermidis'' is not usually pathogenic, patients with compromised immune systems are at risk of developing infection. These infections are generally hospital-acquired. ''S. epidermidis'' is a particular concern for people with catheters or other surgical implants because it is known to form biofilms that grow on these devices. Being part of the normal skin microbiota, ''S. epidermidis'' is a frequent contaminant of specimens sent to the diagnostic laboratory. Some strains of ''S. epidermidis'' are highly salt tolerant and commonly found in marine environment. S.I. Paul et al. (2021) isolated and identified salt tolerant strains of ''S. epiderm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M Protein (Streptococcus)
M protein is a virulence factor that can be produced by certain species of ''Streptococcus''. Viruses, parasites and bacteria are covered in protein and sugar molecules that help them gain entry into a host by counteracting the host's defenses. One such molecule is the M protein produced by certain streptococcal bacteria. At its C-terminus within the cell wall, M proteins embody a motif that is now known to be shared by many Gram-positive bacterial surface proteins. The motif includes a conserved pentapeptide LPXTG, which precedes a hydrophobic C-terminal membrane spanning domain, which itself precedes a cluster of basic residues at the C-terminus. M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (''Streptococcus pyogenes''). It binds to serum factor H, destroying C3-convertase and preventing opsonization by C3b. However plasma B cells can generate antibodies against M protein which will help in opsonization and further the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptococcus Pyogenes
''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus ''Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They are clinically important for humans, as they are an infrequent, but usually pathogenic, part of the skin microbiota that can cause Group A streptococcal infection. ''S. pyogenes'' is the predominant species harboring the Lancefield group A antigen, and is often called group A ''Streptococcus'' (GAS). However, both '' Streptococcus dysgalactiae'' and the '' Streptococcus anginosus'' group can possess group A antigen as well. Group A streptococci, when grown on blood agar, typically produce small (2–3 mm) zones of beta-hemolysis, a complete destruction of red blood cells. The name group A (beta-hemolytic) ''Streptococcus'' (GABHS) is thus also used. The species name is derived from Greek words meaning 'a chain' () of berries ( a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein G
Protein G is an immunoglobulin-binding protein expressed in group C and G Streptococcal bacteria much like Protein A but with differing binding specificities. It is a ~60-kDA (65 kDA for strain G148 and 58 kDa for strain C40) cell surface protein that has found application in purifying antibodies through its binding to the Fab and Fc region. The native molecule also binds albumin, but because serum albumin is a major contaminant of antibody sources, the albumin binding site has been removed from recombinant forms of Protein G. This recombinant Protein G, either labeled with a fluorophore or a single-stranded DNA strand, was used as a replacement for secondary antibodies in immunofluorescence and super-resolution imaging. Other antibody binding proteins In addition to Protein G, other immunoglobulin-binding bacterial proteins such as Protein A, Protein A/G and Protein L are all commonly used to purify, immobilize or detect immunoglobulins. Each of these immunoglobulin-binding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunoglobulin G
Immunoglobulin G (Ig G) is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. Each IgG antibody has two paratopes. Function Antibodies are major components of humoral immunity. IgG is the main type of antibody found in blood and extracellular fluid, allowing it to control infection of body tissues. By binding many kinds of pathogens such as viruses, bacteria, and fungi, IgG protects the body from infection. It does this through several mechanisms: * IgG-mediated binding of pathogens causes their immobilization and binding together via agglutination; IgG coating of pathogen surfaces (known as opsonization) allows their recognition and ingestion by phagocytic immune cells leading to the elimination of the pathogen itself; * IgG activates all the classical pathway of the complement system, a cascade of immune protein pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
