Discrimination of fetal bovine serum from other sera by silver staining or lectin blotting of SDS/PAGE-separated serum proteins.

In order to develop a methodology to discriminate fetal bovine serum from other sera with which it might be contaminated, proteins from fetal bovine, newborn calf, colostrum-free newborn, and calf sera were separated by SDS/PAGE and analyzed by silver staining of the gels or lectin blotting, using concanavalin A (Con A), following transfer of the proteins to nitrocellulose. A high molecular weight Con A-reactive glycoprotein of an apparent molecular mass greater than 200,000 daltons was present in newborn, colostrum-free, and calf sera, but absent or at a significantly lower concentration in fetal serum. These two methods accurately and reliably identified contamination of fetal serum with other sera in a series of blind studies on unknown, coded samples. As little as 1% colostrum-free serum in a batch of fetal serum can be detected by either procedure.