Effects of albumin-bound-fatty acids on the growth of the human T lymphoblastic cell line Jurkat

摘要

To culture a T lymphoblastic cell line, JURKAT, in RPMI 1640 medium, human albumin, instead of fetal bovine serum (FBS), was added to a final concentration of 1% to facilitate growth comparable with FBS. In addition, several kinds of animal albumin were added to the culture, resulting in markedly different growth rates (Fig. 1). In RPMI 1640 medium, amino acids and carbohydrates are included as nutrients, but no lipids. Most fatty acids are binding to serum albumin and alpha fetoprotein (Reed 1986; Copado et al. 1999), and albumin may be the only source of lipids for cultured cells in this study. On the other hand, it is known that fatty acids have various functions to cell growth; i.e., cytotoxicity (Lima et al. 2002; Martins de Lima et al. 2006), induction of apoptosis (Welters et al. 2004; Artwohl et al. 2008), and regulation of signaling (Pawar and Jump 2003). Here, we measured the concentrations of non-esterified fatty acids (NEFAs) in animal albumin (10% solution) using a measuring kit (Wako, Tokyo, Japan), and analyzed albumin-bound NEFAs employing gas chromatography. The amounts of bound NEFAs varied with albumins, being largest for rabbit albumin, followed by sheep, rat, human, and bovine albumins in this order. NEFAs in FBS showed values intermediate between rat and human albumins (Fig. 2A ). Using gas chromatography, fatty acids bound to animal albumins were analyzed to be consisting of palmitic (C16:0), stearic (C18:0), and oleic (C18:1) or linoleic acids (C18:2) similar to NEFAs in FBS used for Jurkat cell culture (Fig. 2B ). However, only rabbit albumin attached a large amount of caprylic acid (C8:0), which presumably caused contamination during the purification process, and sheep albumin attached more than twice as large amount of stearic acid (C18:0) as to rat or human albumin (Fig. 2C ).