Separation of rosette formation-inducing polypeptides from the supernatant of cultures of rat thymic epithelial cell line.
Four polypeptide fractions were isolated by high-pressure liquid chromatography (HPLC) from culture supernatant of rat thymic epithelial cell line (IT-45R1). Biological activity of these fractions was examined according to the capacity inducing rosette-formation between rat thymocytes and guinea pig erythrocytes. A relatively rich population of non-rosette-forming cells (non-RFC), one of targets for thymic hormones, was separated from rat thymocytes by combining rosette-formation method with differential centrifugation. Non-RFC consists of outer-cortical and medullary thymocytes. Medullary thymocytes treated with the polypeptide fraction did not differentiate into RFC. Therefore, the cells, which rosette-forming capacity was induced, seem to derive from outer-cortical area. One of the polypeptide fractions (estimated molecular weight: 3 K) possessed the activity endowing non-RFC with rosette-forming capacity. Since its molecular weight was similar to that of thymosin alpha 1, the fraction was pretreated with anti-thymosin alpha 1 antiserum. The pretreatment suppressed the activity of the fraction. Thus, the fraction must contain thymosin alpha 1 or a polypeptide possessing an antigenic determinant similar to that of thymosin alpha 1. Moreover, two of four subfractions, which were divided from the active fractions by reversed-phase HPLC, showed the biological activity.
Taniyama
T
T
Kinoshita
Y
Y
Hato
F
F
Tominaga
K
K
Kimura
S
S
Itoh
T
T
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D004848:Epithelium / Q000502:physiology; D008297:Male; D010455:Peptides / Q000302:isolation & purification* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012397:Rosette Formation; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives / Q000502:physiology; D013950:Thymus Gland / Q000502:physiology*
D003470:Culture Media; D010455:Peptides; D013947:Thymosin; D000077596:Thymalfasin