Strategic internal covalent cross-linking of TNF produces a stable TNF trimer with improved TNFR2 signaling

Abstract

Background: Soluble TNF superfamily (TNFSF) ligands are less stable and less active than their transmembrane (tm)
analogues. This is a problem for the therapeutic use of recombinant TNFSF ligands in diverse diseases including
cancer and autoimmunity. Creating TNFSF ligand analogues with improved targeting of their respective receptors is
important for research and therapeutic purposes.
Findings: Covalent internal cross-linking of TNF monomers by double mutations, S95C/G148C, results in stable trimers
with improved TNFR2 function. The resulting mutein induced the selective death of autoreactive CD8 T cells in type-1
diabetic patients and demonstrates targeted proliferation and expansion of human CD4 Tregs.
Conclusions: Stable TNF trimers, created by internal covalent cross-linking, show improved signaling. The high
structural homology within the TNF superfamily provides an opportunity to extend internal cross-linking to other
TNF superfamily proteins to produce active trimers with improved stability and receptor signaling, and with
potential applications for cancer, autoimmunity, infections, and transplantation.