Buffer for diluting your primary and secondary antibodies, especially if they were stored for a while, even at -20 in glycerol, or in refrigerator. Nonspecific binding of the antibodies, negative effects of disturbing substances and low or medium affinity cross-reactivities of the antibodies will be minimized, making your result more reliable. Excellent for IHC (frozen and formalin sections), flow cytometry on fixed cells, Western Blot and other immune assays.
When used in pathology, in also greatly reduces non-specific reactivity of human serum components and immunoglobulins in tissue, vessels and cells with mouse antibodies used on section.
For especially "trouble"-giving antibodies, as well as for in situ PCR applications, this dilutent may also be used as a washing buffer, preventing secondary binding of your analystes during washing.