Human lymphotoxin. Production by a lymphoblastoid cell line, purification, and initial characterization

Area of Science:

• Immunology
• Biochemistry
• Molecular Biology

Background:

• Human lymphotoxin is a key cytokine involved in immune responses.
• Previous studies have focused on the biological functions of lymphotoxin.
• A homogeneous preparation of lymphotoxin is essential for detailed biochemical characterization.

Purpose of the Study:

• To purify human lymphotoxin to homogeneity from a lymphoblastoid cell line.
• To characterize the biochemical properties of purified lymphotoxin.
• To analyze the structure of lymphotoxin through tryptic digestion.

Main Methods:

• DEAE-cellulose chromatography
• Preparative isoelectric focusing
• Lentil lectin-Sepharose chromatography
• Preparative polyacrylamide gel electrophoresis
• High-pressure liquid chromatography
• Tryptic digestion

Main Results:

• Purified human lymphotoxin to homogeneity from serum-free tissue culture supernatant.
• Achieved a specific activity of approximately 40 x 10^6 units/mg.
• Determined apparent molecular weight of ~20,000 Da, isoelectric point of 5.8.
• Identified two major tryptic fragments of ~15,000 and ~5,000 Da.

Conclusions:

• Successfully developed a multi-step purification protocol for human lymphotoxin.
• Established key biochemical parameters of purified human lymphotoxin.
• Provided initial structural insights through analysis of tryptic fragments.