Bovine colostrum fraction as a serum substitute for the cultivation of mouse hybridomas

Fractions of bovine colostrum were prepared and their ability to support the growth of mouse-mouse hybridomas in culture was tested. Whey was prepared from defatted colostrum by removal of casein using acid precipitation. An ultrafiltrate was obtained from cleared whey by filtration through membranes with a nominal molecular mass cut-off of 100,000 Da. Colostrum ultrafiltrate contained 1.16 milligrams protein, 0.24 milligrams immunoglobulin G (IgG) and less than 0.24 EU (endotoxin unit)/ml endotoxins. The effect of defatted colostrum, whey and ultrafiltrate as serum substitutes was examined by cultivation of hybridoma cells in minimal essential medium containing different concentrations of the supplements. Under optimal conditions in ultrafiltrate-supplemented medium, the maximal cell concentration was 35-40% of that obtained using 10% foetal bovine serum, and IgG production per cell was equal to that achieved using serum. In 1% defatted colostrum the maximum hybridoma concentration was about 30% of that in 10% serum, but at higher concentrations hybridoma growth was significantly reduced. The growth-promoting activity of whey was low. The results show that bovine colostrum ultrafiltrate provides a very attractive alternative to serum for production of monoclonal antibodies.