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TGFβ2 is present in infant formula, resists digestion in vitro and is biologically active
Author(s) -
Lonnerdal Bo,
Du Xiaogu,
Morris Kristin,
Jouni Zeina,
Rai Gyan,
Waworuntu Rosaline
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.344.1
Subject(s) - pepsin , proteolysis , digestion (alchemy) , in vitro , enzyme , chemistry , transforming growth factor , biological activity , infant formula , trypsin , hydrolyzed protein , proteolytic enzymes , biochemistry , biology , endocrinology , chromatography
TGFβ2 is present in human milk and believed to be important for IgA production and oral tolerance. Concentrations are lower in bovine milk, but by utilizing milk protein sources high in TGFβ2, formula TGFβ2 can be increased. We investigated whether TGFβ2 in human milk and formula can resist proteolysis under conditions similar to those in the infant gut. Human milk and formulas were exposed to pepsin at pH 5.0, 3.5 or 2.0 (reflecting increasing maturity of the infant gut) at 37C for 30 min, neutralized to pH 7.0 and incubated for 30 min with pancreatic enzymes. TGFβ2 was analyzed by ELISA. TGFβ bioactivity was assessed by a Smad2 redistribution assay using a Cellomics ArrayScan system and by inhibition of IL‐2 stimulated growth of HT‐2 cells. TGFβ2 levels in formula were variable, but in some cases exceeded those of human milk samples. Digestion with pepsin at pH 2.0 or 3.5 substantially increased immunodetectable TGFβ2 in formula, and digestion with pancreatic enzymes increased it further. This suggests that acidification and/or proteolysis play important roles in liberation of immunodetectable TGFβ2. TGFβ2 in digests (pepsin+pancreatin) was highly bioactive by both assays used. In summary, TGFβ2 in infant formula continues to be immunodetectable and retains activity after in vitro digestion, strongly suggesting that TGFβ2 can survive in the infant gut and exert its biological activities. Supported by Mead Johnson.