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.
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.
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.
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.
