a1 Department of Nuclear Medicine, Faculty of Medicine, Kanazawa University, 13–1 Takaramachi, Kanazawa, Ishikawa-ken 920, Japan
a2 Department of Molecular Immunology, Cancer Research Institute, Kanazawa University, 13–1 Takaramachi, Kanazawa, Ishikawa-ken 920, Japan
Bovine colostrum contains transforming growth factor (TGF)-β-like activity. High levels of this activity are found in early colostrum (within 12 h after parturition); however, it decreases rapidly after 30 h. In this study, the activity in early colostrum was purified by a sequence of decaseination, DEAE-Sephacel chromatography, Sephadex G-100 gel filtration, precipitation at neutral pH, further gel filtration and reversed-phase FPLC. A homodimeric 23 kDa protein was identified that retained the TGF-β-like activity. Its activity was completely neutralized by a specific anti-TGF-β2 antibody. These results indicate that the TGF-β-like growth factor found in bovine colostrum is chemically and antigenically related to TGF-β2. The physiological roles of the TGF-β2-related growth factor are discussed.
(Received April 09 1992)
(Accepted August 12 1992)