Thymic stroma-derived T-cell growth factor (TSTGF): II. Biochemical and functional characterization

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Thymic stroma-derived cells produce factors influencing T-cell development.
• Interleukin-2 (IL-2) dependent T-cell clones require specific growth factors.

Purpose of the Study:

• To identify and characterize a novel growth factor from thymic stroma-derived cells.
• To investigate the properties of this factor supporting T-cell proliferation.

Main Methods:

• Partial purification using DEAE-Sephacel chromatography and PBE 94 chromatofocusing.
• Analysis of molecular weight via Sephacryl S-200 column chromatography and SDS-PAGE.
• Assessment of stability and activity after heat, pH, trypsin, and dithiothreitol treatments.

Main Results:

• A factor, termed thymic stroma-derived T-cell growth factor (TSTGF), was identified.
• TSTGF activity was separated from IL-1, IL-2, IL-3, IL-4, interferon, and colony-stimulating factor (CSF) activities.
• Purified TSTGF exhibited an isoelectric point (pI) of approximately 6.0 and an apparent molecular weight of about 25,000.
• TSTGF demonstrated stability to heat and pH variations but was inactivated by trypsin and dithiothreitol, indicating a protein nature and dependence on disulfide bonds.

Conclusions:

• TSTGF is a novel protein growth factor for T-cells.
• The factor has a molecular weight of ~25,000, pI of 6.0, and requires intact disulfide bonds for biological activity.
• This discovery offers new insights into T-cell regulation and growth factor biology.