Generation of mutant leukaemia inhibitory factor (LIF)–IgG heavy chain fusion proteins as bivalent antagonists of LIF
Jazayeri, J. A., De Weerd, N., Raye, W., Velkov, T., Santos, L., Taylor, D., et al. (2007). Generation of mutant leukaemia inhibitory factor (LIF)–IgG heavy chain fusion proteins as bivalent antagonists of LIF. Journal of Immunological Methods, 323(1), 1-10. doi:10.1016/j.jim.2007.02.011
Two leukaemia inhibitory factor (LIF) mutants, designated MH35-BD and LIF05, have been shown to have a capacity to inhibit the biological activities of not only human LIF (hLIF) but also other interleukin-6 (IL-6) subfamily cytokines such as human oncostatin M (hOSM). These cytokines share the same receptor complex in which the glycoprotein 130 (gp130) subunit is a common constituent. However, at low concentrations and in their monomeric forms, such molecules have a relatively short plasma half-life due to rapid clearance from the kidneys. Here, to prolong their serum half-lives, we have used a multi-step polymerase chain reaction (PCR) to fuse each of the LIF05 and MH35-BD cDNA fragments to a sequence encoding the Fc portion, and the hinge region, of the human immunoglobulin G (hIgG) heavy chain. The linking was achieved through an oligomer encoding a thrombin-sensitive peptide linker thus generating MH35-BD:Fc and LIF05:Fc, respectively. Both Fc fusion constructs were expressed in insect cell Sf21 and the proteins were purified by two successive affinity chromatography steps using nickel–nitrilotriacetic acid (Ni–NTA) agarose and protein A beads. The Ba/F3 cell-based proliferation assay was used to confirm that the proteins were biologically active. In addition, preliminary pharmacokinetics indicates that the Fc fusion constructs have a longer serum half-life compared to their non-fusion counterparts.
cytokines, leukaemia inhibitory factor (LIF), Fc proteins, insect cell expression