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ELISA Buffer

ELISA is a convenient and sensitive method for assaying antibodies and antigens, and is widely utilized in many fields.  However, false positive reactions have been erroneously interpreted as real antibody-antigen reactions all too often, and have misled the research and clinical field.  In order to improve the antibody assay method in ELISA, Chondrex provides ChonBlock; a buffer that can be used for blocking (Figure 1) and sample dilution (Figure 2).  ChonBlock is especially useful for assaying autoantibodies in human and animal sera at low dilutions, where the likelihood of false positive reactions is greater, as well as for assaying anti-environmental factor antibodies which are often underestimated due to interference caused by buffer components.

ELISA Buffer

Product Quantity Catalog # Price (USD)
ChonBlock Blocking/Sample Dilution ELISA Buffer 100 ml 9068 50.00
ChonBlock Detection Antibody Dilution Buffer 100 ml 90681 50.00

Figure 1.  Prevention of false positive reactions.
Human serum samples diluted 1:100 with 5% BSA-Tween,  Normal Goat Serum (NGS) and ChonBlock were added to antigen non-coated, human type I collagen (HI) and human type II collagen (HII) coated wells.  BSA is not capable of blocking the hydrophobic binding of immunoglobulin components in sample specimens onto plastic surfaces, therefore almost identical OD values were observed in all wells regardless of ELISA plate coating.  In contrast, ChonBlock prevents this type of non-specific reaction, and clearly distinguishes the true antibody-antigen reactions from false positive reactions as effectively as NGS.

Figure 2.  Accurate measurement of anti-environmental factor antibodies.
Human serum was serially diluted with Normal Goat Serum (NGS) and ChonBlock, and assayed for anti-E. coli antibodies.  NGS which contains antibodies against virtually all potential environmental factors apparently inhibits the anti-E. coli antibodies in human serum by competitive binding.  In contrast, ChonBlock, which does not interfere with antibodies and antigens, allows for an accurate assay of the true antibody titer in human serum.