When carrying out immunofluorescence, for a protein in a mouse test subject, why is it necessary to make the secondary antibody from an anti-mouse serum?
In some advanced testings such as immunohistochemistry, background staining is the big issue. A separately raised antibody from another animal has to take that role of proper conjugation to the chromogen/marker/indicator.
The secondary antibody has to match the first Ab host; otherwise, the 2Ab would not bind the 1Ab. For example, if the 1Ab is a rabbit Ab, the 2Ab has to be any source-anti-rabbit.
In some advanced testings such as immunohistochemistry, background staining is the big issue. A separately raised antibody from another animal has to take that role of proper conjugation to the chromogen/marker/indicator.
most home-made antibodies are obtained from rabbit, an animal whose size allows relatively simple manipulations (Ag injection, Ab recovery), the variable region of Ab being responsible of the recognition specificity ; but these Ab are undetectable by a simple way ; commercial firms have developed secondary Ab which for ex recognized all the rabbit Ab (due to the constant region of Ig which are used as Ag in a second animal species for ex goat) and with cost minimization this allows the scientific community (and teachers and students) to dispose of a cheap tool
The purpose is to avoid cross-reactivity of the secondary anti-immunoglobulin antibody with endogenous immunoglobulins in the sample, that is, for techniques that use such samples.