Immunochemistry Protocols: Immunopurification ‐ (Small Scale) Using Anti‐Epitope Tag Affinity Matrices:Typically, immunoprecipitation of antigen from extracts of transfected mammalian cells requires between 1-5 μL of polyclonal antiserum, 5-100 μL of hybridoma tissue culture medium, or 1-3 μL of ascites. If more antibody is used than is necessary, nonspecific background will increase. The concentration of immunoglobulins in antiserum is approximately 6-8 mg/mL. Supernatant from cultured hybridoma cells typically contains 10-100 μg/mL immunoglobulin, and ascites fluid contains 5-7 mg/mL immunoglobulin.