Although it is impossible to claim stability data for every possible application and use for human serum AB, we conservatively estimate that if this product is stored properly at -20ºC, it can be used for 5 years from the date of manufacture without any decrease in product performance. Storage at any other temperature may affect results.
Gemini Bio-Products goes to great lengths to ensure that our human sera are the most consistent products commercially available. Although our human serum is manufactured using raw material from congruous donor pools and according to time-tested protocols, it is possible to perceive differences in the physical appearance of this product from lot-to-lot. This phenomenon can be largely attributed to variation in diet amongst human beings (particularly with respect to dietary fats).
Due to a diet higher in fats and oils, human serum typically contains higher levels of lipids than serum from other sources. Even after sterile filtration through 0.1mm filters, particles remain suspended in solution that can aggregate and precipitate as a result of subsequent freezing, thawing and/or heat-inactivation. It is for this reason that we suggest minimizing such temperature changes. The presence of particulate matter does not indicate contamination of any sort, and does not negatively impact the serum’s performance.
The practice of heat inactivating serum was originally developed when only serum from adult sources was available for cell culture. Adult serum contains various immune factors, particularly serum complement, which may inhibit or destroy cells under certain conditions. Heat Inactivation (HI) was originally introduced for the purpose of reducing serum complement activity.
Off-the-clot serum is collected from blood that is allowed to coagulate naturally after collection. It has not been exposed to any anticoagulant. Plasma-derived serum is produced by defibrinating pooled human plasma collected in the presence of an anticoagulant, such as sodium citrate. Plasma-derived serum, such as Gemini’s human serum AB (cat# 100-512), is generally more economical and consistent than off-the-clot product. Off-the-clot serum is, however, available in original transfer packs from individual donors, a feature attractive for certain metabolic studies.
Human serum yields superior results when culturing many types of human cells, particularly those associated with the human immune system. Human serum is used to supplement lymphocyte culture media, as a blocking agent for immunohistochemical staining procedures, and as a negative control in human leukocyte antigen (HLA) tissue-typing applications.