[Preliminary study on the purification of IL-2]

Area of Science:

• Biochemistry
• Protein Chemistry
• Chromatography

Context:

• Interleukin-2 (IL-2), a T-lymphocyte-produced protein, is crucial for immune responses and has therapeutic potential in cancer and AIDS.
• Existing purification methods may not be optimal for large-scale IL-2 production.
• IL-2's structure includes a disulfide bridge and a free cysteine, requiring careful handling to prevent aggregation.

Purpose:

• To develop and describe a novel, scalable method for purifying Interleukin-2 (IL-2).
• To utilize preparative high-performance liquid chromatography (HPLC) with hydroxyapatite for IL-2 separation.
• To optimize conditions preventing IL-2 aggregation and incorrect disulfide bond formation during purification.

Summary:

• A two-step chromatographic process was employed: Sephadex G-25 gel permeation to remove denaturants and preparative HPLC using hydroxyapatite for IL-2 isolation.
• Autoxidation and denaturation using Cu2+ and guanidine hydrochloride were performed to manage IL-2's disulfide bonds and free cysteine.
• Gradient elution with phosphate buffer (pH 6.8) was used in the HPLC step, followed by SDS-PAGE for purity assessment.

Impact:

• The described method demonstrates suitability for large-scale Interleukin-2 purification.
• Achieved high purity and activity (1 x 10(6) U/mg) of IL-2, validated by CTLL-2 cell MTT assay.
• Provides a robust protocol for obtaining biologically active IL-2 for research and potential therapeutic development.