Proteins of Pathogenic Bacteria

The limitations of ELISA methods include the specificity of antibodies, the concentrations of primary antibody and antigen, and the type of reaction solution. Nonspecific binding of either of the antibodies to related antigens, unrelated proteins of other bacteria, or even the microtiter plate may lead to false positive reactions.49,52 57 Use of a monoclonal antibody may decrease crossreactivity with other antigens. For detection of low numbers of bacteria, as in drinking water, the sample may be filtered to concentrate the cells or cultured in a selective broth until it reaches the minimum detection limit for ELISA.49,58 Commercial test kits using dipsticks, immunoblots, and sandwich ELISA methods have been developed for the identification of pathogenic bacteria.58,59... 

Some species of pathogenic bacteria, notably Streptococci and Staphylococci, have proteins on their surface which bind immunoglobulins (1). Protein A from Staph, aureus and protein G from species of Streptococci, which are widely used as immunological tools, are the most extensively studied of these antibody-binding proteins. 

Several highly immunogenic bacterial proteins have been proposed as carriers for conjugate vaccines. The list includes bacterial pili, outer membrane proteins (OMPs), and excreted toxins of pathogenic bacteria [105], preferably in toxoid fomr Tetanus and diphteria toxoids, which are readily available and accepted for human use, are the preferred carrier despite the lot-to-lot variations during the detoxification procedure. 

The tool kit consisting of carbohydrate synthesizer and carbohydrate microarrays lays the foundation for the discovery and elucidation of new drugs, as studies with the fully synthetic antitoxin malaria vaccine candidate have shown. HIV neutralizing proteins have been identified by studies with carbohydrate microarrays aminoglycoside microarrays were used to test antibacterial resistance. Fluorescent polymers can be utilized to detect small amounts of pathogenic bacteria in a short time. 

A number of pathogenic bacteria produce bacterial toxins that are ADP-ribosyl transferases (NAD+-glycohydrolases). These enzymes hydrolyze the N-glycosidic bond of NAD+ and transfer the ADP-ribose portion to a specific amino acid residue on a protein in the affected human cell. Cholera A-B toxin, a pertussis toxin, and a diptheria toxin are all ADP-ribo-syl transferases. 

The capacity of pathogenic bacteria to adhere to mucosal membranes has been exploited in the modification of new mucoadhesive polymers. The ability of bacteria to adhere to a specific target is rooted from particular cell-surface components or appendages, known as fimbriae, which promote adhesion to other cells or inanimate surfaces. Fimbriae are extracellular, long thread-like protein polymers of bacteria that play a major role in many diseases. It has been reported that Escherichia coli adheres specifically to the lymphoid follicle epithelium of the ileal Peyer s patch in rabbits. Similarly, different staphylococci possess the ability to adhere specifically to the surface of mucus gel layers and not mucus-free surfaces. Thus, polymers have been modified by the attachment of these fimbriae to enhance mucoadhesion. An attachment protein derived from E. coli, K99-fimbriae, has been covalently attached to polyacrylic acid networks in an attempt to provide a novel polymer with enhanced adhesive properties (Figure 52.7). ... 

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