Lymphokine purification by reversed-phase high-performance liquid chromatography.

Area of Science:

• Biochemistry
• Protein Chemistry
• Analytical Chemistry

Background:

• Lymphokines are crucial signaling proteins involved in immune responses.
• High purity of lymphokines is essential for accurate biological and structural studies.
• Previous purification methods for these lymphokines were often complex or yielded impure preparations.

Purpose of the Study:

• To develop and apply a robust purification strategy for human Interleukin-2 (IL-2) and murine Colony-Stimulating Factor 2 alpha (CSF-2 alpha).
• To confirm the homogeneity and integrity of the purified lymphokines using advanced analytical techniques.
• To validate the amino acid sequences of the purified proteins against existing genetic data.

Main Methods:

• Utilized reversed-phase high-performance liquid chromatography (RP-HPLC) with distinct solvent systems (pyridine-acetate-propanol and trifluoroacetic acid-acetonitrile).
• Employed C8 and C18 stationary phases for sequential purification steps.
• Performed protein sequence analysis on cyanogen bromide-generated peptides.
• Analyzed purity using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

Main Results:

• Human IL-2 was purified to homogeneity using a two-step RP-HPLC process, with sequence analysis confirming its predicted amino acid sequence.
• Murine CSF-2 alpha was purified to homogeneity via a similar two-step RP-HPLC strategy.
• The final murine CSF-2 alpha preparation showed a single band on SDS-PAGE, corresponding to a molecular weight of 24,500 Da.

Conclusions:

• Reversed-phase HPLC is a highly effective method for purifying lymphokines like IL-2 and CSF-2 alpha to homogeneity.
• The established purification protocols ensure protein integrity and allow for sequence confirmation.
• This work provides highly purified lymphokine preparations suitable for further functional and structural investigations.