• About Human Serum/关于科研用人血清产品
  • 点击数:  发表日期:2008-8-15
  • 1Why use human serum?

    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.

    2Why use human serum type AB

    Human serum from type AB donors lacks antibodies against the A and B blood-type antigens. Human serum AB is commonly used when there is the need to minimize immunoreactivity.

    3How many donors contribute to a lot of human Serum?

    Each lot of human serum type AB typically derives from 200-250 pre-screened donors.

    4What are the advantages of using all male donors?

    Women who have been pregnant may develop antibodies against major histocompatibility class (MHC) antigens carried on the father’s cells and/or the fetus' cells. Male donors present no such risks.

    5What is the difference between off-the-clot and plasma-derived human serum?

    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, 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.

    6Should I heat inactivate human serum?

    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. Today, serum is often heat-inactivated without evidence of beneficial effect, but simply because an earlier protocol calls for such action. Since most cells grow perfectly well without HI, we ask that the necessity of this process be seriously examined prior to HI of human serum to see that it is absolutely necessary. HI of human serum will lead to increased precipitate levels in the product, due mainly to higher overall levels of lipids in the human diet as compared to bovine or other animal sera. Although the presence of this precipitate will not affect the product’s performance in culture, it can lead to filtration and/or visualization issues.If, in light of the above, you would still prefer to heat-inactivate your serum.

    7Why do I notice particulate matter in some human serum?

    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.

    8Why do different bottles of human serum sometimes look different from one another?

    Our 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). Another source for slight differences comes from non-uniform storage conditions and/or handling variations in the laboratory setting. Due to the special sensitivity of this product (as compared to other sera), it is critical that human serum be cared for as recommended by the manufacturer.  

    9How long can frozen human serum be stored?

    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 2 years from the date of manufacture without any decrease in product performance. Storage at any other temperature may affect results.