Staphylococcus aureus, protein produced

J.J. Langone, Protein A of Staphylococcus aureus and related immunoglobulin receptors produced by streptococci and pneumonococci. Adv. Immunol. 32,157—252 (1982). 

Protein A, produced by Staphylococcus aureus, binds IgG. It is used extensively in antibody purification protocols Lectins are a group of proteins capable of binding carbohydrates. 

Along this line Matsue et al. [37,45,78,79] have developed a number of biochips. Among them are multi-analyte assays for human placental lactogen (HPL) and human chorionic gonadotropin (HCG) [45] and leukocidin, a toxic protein produced by methicillin-resistant Staphylococcus aureus [79]. Figure 37.8 shows an example of a dual immunoassay with SECM detection. The analyte is defined by the position on the chip and the amount of analyte is quantified via the collection current at the UME. The current originates from the reduction of ferrocinium methanol (Fc+) at the UME. Fc+ is produced locally at the chip surface by the enzyme HRP under consumption of H202. 

It has been possible to produce vaccines to use for immunization against certain bacterial infections and other human diseases. Staphylococcus aureus capsular polysaccharide in combination with a carrier protein has been used to prepare monovalent vaccines specific for S. aureus [86], The vaccine was administered to groups of healthy adults and to patients with end-stage renal disease. The antibodies are directed at the polysaccharide moiety of the glycoconjugate. The data of this study show that conjugate-induced antibodies to S. aureus can provide partial protection against S. aureus bacteremia, Fig. (45). 

Chang, Y. H., Chang, T. C., Kao, E. F., et al. (1996) Detection of protein A produced by Staphylococcus aureus with a fiber-optic-based biosensor. Bioscience Biotechnology and Biochemistry 60 1571-1574. 

Protein A (PA) is a cell wall component produced by over 98% of the strains of Staphylococcus aureus that have been tested. It was reported first by Verwey, then rediscovered by Jensen nearly two decades later Its name emphasizes the chemical class, since PA originally was believed to be a polysaccharide, but shown later to be a protein with little or no carbohydrate. The outsmnding functional property of PA is its ability to bind specifically to the Fc region of immunoglobulin molecules, especially... 

Staphylococcus aureus produces a set of proteins [e.g., staphylococcal enterotoxin A (SEA), SEB, toxic shock syndrome toxin 1 (TSST-1)], which act both as superantigens and toxins. Hamad and coworkers (66)found dose-dependent, facilitated transcytosis of SEB and TSST-1, but not SEA, in Caco-2 cells. They extended their studies in mice in vivo by showing that ingested SEB appears in the blood more efficiently than does SEA. 

To increase the purity or to concentrate an antibody solution, it may be purified. Purification is done with a range of techniques applied to whole serum, supernatant, or ascites fluid. At the first level, the purified Ig will be separated from other serum proteins and will select all IgGs including the IgG of interest and other IgG molecules. These purification steps can be done by using ammonium sulfate to precipitate the Ig molecules or it can be done by binding antibodies to a Protein A and/or Protein G columns. Proteins A and G are produced by the bacteria. Staphylococcus aureus, and bind to different species and subclasses of antibodies by the Fc receptor. After the antibodies have attached, they are washed out by changing the buffer. 

Staphylococcal enterotoxins (SEs) are the most widely studied of the toxic foodborne proteins. Although these toxins are produced by various strains of Staphylococcus, evidence has shown they are primarily produced by the Staphylococcus aureus strain. Currently there are nine enterotoxins (A, B, C, D, E, G, H, I, J) that have been identified in a wide variety of food products meat, poultry and egg products, milk and dairy products, as well as bakery products [35]. The infective dose of toxins is estimated to be 0.1 p-g/kg body mass [36]. Detection of the presence of SEs is typically done through isolation in the suspected food source [6]. 

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