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Thymic Stroma‐Derived T‐Cell Growth Factor (TSTGF): II. Biochemical and Functional Characterization
Author(s) -
Sato Soichiro,
Ogata Masato,
Sano Haruo,
Mizushima Yumiko,
Muramatsu Minoru,
Doi Hideyuki,
Itoh Tsunetoshi,
Hamaoka Toshiyuki,
Fujiwara Hiromi
Publication year - 1988
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.44.3.149
Subject(s) - chromatofocusing , dithiothreitol , biology , isoelectric point , microbiology and biotechnology , isoelectric focusing , gel electrophoresis , polyacrylamide gel electrophoresis , cell culture , clone (java method) , biochemistry , enzyme , dna , genetics
The culture supernatant (SN) from a cloned line of thymic stroma‐derived cells in fibroblastic form (TSCF) contained a factor capable of supporting the growth of the interleukln (IL) 2‐dependent, antigen‐specific helper T cell (Th) clone 9‐16 without requiring IL2 and antigen. This active substance, designated as thymic stroma‐derived T‐cell growth factor (TSTGF), was partially purified through DEAE‐Sephacel chromatography and PBE 94 chromatofocusing. The original SN did not contain IL1, IL2, IL3, IL4, or interferon activities; but an appreciable magnitude of colony‐stimulating factor (CSF) activity in addition to TSTGF was present, whereas the partially purified preparation of TSTGF was depleted of any type of CSF activity. The elution profile of TSTGF activity on the chromatofocusing has revealed that TSTGF has an isoelectric point (pI) of about 6.0. When a purified TSTGF sample was applied to Sephacryl S‐200 column chromatography and sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis, TSTGF activity was eluted in a single peak around an apparent molecular weight of about 25,000. The activity of TSTGF also was shown to be relatively stable with heat treatment and in the wide range of pH, but it was abolished by treatment with either trypsin or dithiothreitol. These results indicate that TSTGF, a novel T‐cell growth factor, is the protein that has an apparent molecular weight of about 25,000 and a pI of 6.0, and in the intact molecule, it contains the disulfide bond(s) required to maintain and/or express its biologic activity.