EXPRESSION OF HUMAN IL-2 GENE IN ESCHERICHIA COLI
Abstract
Interleukin-2 (IL-2) is historically known as a T-cell growth factor. It is a centtal regulator in the immune system and mediates its effects. Administtation of high or intermediate doses of exogenous IL-2 has been used as an anti-tumor tteatment in humans, especially for renal and melanoma. Therefore, in 1992, the high-dose of recombinant IL-2 was approved by the Food and Dmg Administtation (FDA) to use for cancer tteatment. In order to develop recombinant IL-2 in Vietaam, we established a new strategy to express IL-2 protein from E. coli. In this sttategy, IL-2 which was not fused with any other protein, was expressed as inclusion bodies. The
recombinant protein was recovered efficiently by the method of denatured purification to separate recombinant IL-2 from other unexpected soluble proteins expressed in E. coli cells. In this report, the result of human il-2mn gene expression was shown. Based on the available pET32-Trx-IL2MN plasmid, the gene sequence was easy to amplify by PCR with specific primer pair and cloned into pET22b(-i-) vector in E. coli BL21 cell. After expression in LB medium, the experiment result showed that the optimal conditions to express recombinant IL-2 should be at 37°C with 1 mM final concenttation of inducer isopropyl-beta-D-thiogalactopyranoside (IPTG)
and the point to start induction at high cell density (OD ^oo from 0.9 to 1.2). This resuh also demonsttated that most expressed recombinant IL-2 was in the form of inclusion bodies as the purifying sttategy expected.