The gene encoding the natural ligand of murine glucocorticoid-induced tumor necrosis factor receptor (GITR) was cloned and characterized. The putative GITR ligand (GITRL) is composed of 173 amino acids with features resembling those of type II membrane proteins and is 51% identical to the human activation-inducible TNF receptor (AITR) ligand, TL6. Expression of the GITRL is restricted to immature and mature splenic dendritic cells. GITRL binds GITR expressed on HEK 293 cells and triggers NF-kB activation. Functional studies reveal that soluble CD8-GITRL prevents CD4 þ CD25 þ regulatory T-cell-mediated suppressive activities.

Although carboxylate-based frameworks are commonly used architectures in metal-organic frameworks (MOFs), liquid/glass MOFs have thus far mainly been obtained from azole- or weakly coordinating ligand-based frameworks.1,2 This is because strong coordination bonds of carboxylate ligands to metals block the thermal vitrification pathways of carboxylate-based MOFs.3 In this study, we present the first example of carboxylate-based melt-quenched MOF glasses comprising Mg2+ or Mn2+ and an aliphatic carboxylate ligand, adipate. These MOF have a low melting temperature (Tm) of 284 °C, compared to zeolitic-imidazolate framework (ZIF) glasses,4,5 and superior mechanical properties in terms of hardness and elastic modulus.6 The low Tm is due to the flexibility and low symmetry of the aliphatic carboxylate ligand (raising entropy of fusion (ΔSfus))7,8 and the lack of crystal field stabilization energy on metal ions (reducing enthalpy of fusion (ΔHfus)).9 This research will serve as a cornerstone for the integration of numerous carboxylate-based MOF into MOF glasses.