Immune system biotin

Polyporus umbellatus (Pers.) Fr. Zhu Ling (dried fungus) Ergosterol, biotin, protein.33 Diuretic, stimulate the immune system, anticancer. 

Using the ELISA (with avidin-biotin bridges) and ELISPOT methods a stimulating effect of selected probiotic bacteria (Bifidobacterium longum, B animalis, Lactobacillus easel, L. salivarius) on the immune system of the rat and mouse has been demonstrated (higher level of specific as well as total IgGa and IgA content) (Nagy et al., 2002). 

One of the two m or steps in the application of avidin-biotin technology is to incorporate the biotin moiety into the experimental system (6). This is usually accomplished by covalendy attaching biotin to a biologically active binder. The binder can be an antigen, a primary monoclonal or polyclonal antibody, a complement, interleukin-2, or any other component of the immune system. 

Owing to the strength of the avidin-biotin complex, the immunochemical bond can be preferentially severed, permitting selective elution of the antigen. Variations on this same theme allow the immunoaffinity isolation of other components of the immune system, such as tmtibodies, complements, blood cell receptors, and the like. 

Fig. 1. Schematic drawing of various immune methods for localization of antigens. (A) Direct method. (B) Indirect method. (C) Immunogold with silver enhancement. (D) Peroxidase-antiperoxidase method. (E) Avidin-biotin system.

The immune complex transfer assay has allowed the development of very sensitive EIAs for the detection of antibodies. In one example, the assay utilizes a 2,4-dinitrophenyl (DNP)-biotin-conjugated antigen. This is incubated with the sample antibody to be measured, and, after the immune reaction, the immune complexes are trapped onto a primary solid phase coupled with anti-DNP antibody. After washing away unbound materials, immune complexes are eluted with DNP-lysine and transferred to a secondary streptavidin-coated solid phase. Next, an enzyme-labeled anti-immunoglobulin antibody is added, and, after washing, enzyme activity is assayed. In this case, the enzyme activity correlates with the amount of antibody in the sample. The sensitivity depends on the amount of nonspecific binding of the enzyme-labeled antibody on the second solid phase. Thus, several modified assay systems have been developed to reduce background. 

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