Antigens dextrans

Antigen Cross-linking Antigen- Dextran Gating of [9]... 

TEMPORARY SKIN SUBSTITUTE FROM NON-ANTIGENIC DEXTRAN HYDROGEL... 

The potentials of a hydrogel made from the non-antigenic dextran as a biomedical material have not been fully explored. The cost of the hydrogel membrane is only about 10/ft. If results from future clinical trials corroborate with our observations in the animal experiment, it will be interesting to evaluate other possible biomedical applications for this material. 

Some antigens, such as type 3 pneumococcal polysaccharide, EPS and other polymeric substances such as dextrans (poly-D-glucose) and levan (poly-D-fructose) can induce antibody synthesis without the assistance of TH cells. These are known as T-independent (Ti) antigens. Only one class of immunoglobulin (IgM) is synthesized and there is a weak memory response. 

Zozaya40 reported that nitrogen-free L. mesenteroides dextran was not antigenic, but could be rendered antigenic by adsorption upon a... 

Dextran resulting from the action of another strain of L. mesenteroides (designated for convenience, strain B) was more soluble than strain A dextran and exhibited somewhat different immunological reactions. This strain B dextran reacted only slightly with pneumococcus Type XII antisera and had a narrower zone of antigenic reactivity than the strain A dextran. In addition, the strain A organisms exhibited a greater capacity to absorb antibodies reactive with the B dextran than did the B bacteria to absorb antibodies reactive with the A dextran. 

Manabe, Y., Tsubota, T., Haruta, Y., Okazaki, M., Haisa, S., Nakamura, K., and Kimura, I. (1983) Production of monoclonal antibody-bleomycin conjugate utilizing dextran T40 and the antigen-targeting cytotoxicity of the conjugate. Biochem. Biophys. Res. Comm. 115, 1009. 

Some separation techniques rely on the physical removal of one of the fractions charcoal will strongly adsorb the free fraction allowing its ready removal by centrifugation the addition of dextran reduces the tendency of charcoal to strip bound antigen from the complex alternatively, the bound fraction may be precipitated by the addition of suitable concentrations of various protein precipitants such as alcohol, ammonium sulphate and polyethylene glycol (PEG). 

Avseenko et al. (2001) immobilized antigens onto aluminum-coated Mylar films by electrospray (ES) deposition. Various surface modifications of the metallized films were studied to determine their abilities to enhance sensitivity. The plastic surfaces were firsf cleaned by plasma discharge treatment, followed by coating with proteins (BSA and casein) or polymers such as poly (methyl methacrylate) or oxidized dextran, or they were exposed to dichlorodimethyl silane to create hydrophobic surfaces. Protein antigen was prepared in 10-fold excess sucrose and sprayed onto the surfaces to form arrays with spot diameters between 7 and 15 pm containing 1 to 4 pg protein. 

Antigens and their corresponding antibodies precipitate by cross-linking to form an insoluble network. Polysaccharides have multiple, repetitive immunodeterminants and virtually none have demonstrable tertiary structure in solution (except, perhaps, under viscous stress). The number of these immunodeterminant groupings on each macromolecule is large. In the case of dextran, for instance, there are several thousand of them (if the dextran has a molecular weight of several million), even if the determinant involves the hep-tasaccharide. There is, thus, ample opportunity to form a precipitating, crosslinked complex with divalent (or polyvalent) antibody molecules. 

---