Purified Interleukin-2

NOTE: Not for human or diagnostic use.

Procedure for Use of Human T-Cell Growth Factor (TCGF)

1. Prepare isolated human T-lymphocytes from blood using a cell separation medium such as Histopaque or lymphocytic separation medium (LSM). Wash T-cells 3 times in RPMI-1640 fetal bovine serum 10%.
2. Expose T-cells at a concentration of 1 × 10⁶ cells per mL to a mitogen such as phytohemagglutinin (PHA) to activate cells for TCGF-dependent growth in vitro. Incubate activated cells 5 days at 37°C in 5% CO₂.
3. Wash cells 3 times in RPMI-1640 fetal bovine serum 10%. Resuspend cells to a concentration of 5 × 10⁵ cells/mL in RPMI-1640 supplemented with 10 to 20% fetal bovine serum and 10% volume of TCGF.
4. To split cultures, pellet cells and resuspend back to 4 to 6 × 10⁵ cells/mL every 3 to 5 days using fresh RPMI-1640 fetal bovine serum 10 to 20% plus a 10% volume of TCGF.
5. To establish long-term cultures of T-lymphocytes, repeat step 4 as necessary.

Production of TCGF: Human T-cell growth factor (TCGF) is prepared from pooled human blood leukocytes, separated on Ficoll-Hypaque and stimulated with purified phytohemagglutinin (PHA). Following induction with PHA, the leukocytes are incubated for 48-72 hours in RPMI-1640 and the crude TCGF fluids harvested.

Purification: Crude TCGF fluids are clarified by centrifugation, purified by chromatographic methods and the purified TCGF sterile filtered into vials.

Quality Control: Each lot of TCGF is screened and found to be free of bacteria, yeasts, molds and Mycoplasma by accepted laboratory methods. The product is lectin-free and capable of stimulating long-term growth of adult human T-lymphocytes when assayed by long-term proliferation assays in vitro or by tritiated thymidine uptake.

TCGF Assay: In vitro proliferation assay in lectin activated T-cells: Reciprocal dilution of TCGF supporting T-cell dependent cell population doubling in 72 hours (Titer = 1:64).

Specific Activity: 640 half-maximal units/mL.