Figure 1: Schematic of combination of 131I-ELP brachytherapy and ELP-K12/CpG immunotherapy.
ELP brachytherapy is formulated as a 131I radionuclide conjugated to Tyr residues at the C-terminus of an ELP (131I-ELP), while CpG is electrostatically complexed to a (Lys)12 peptide at the C-terminus of an ELP (ELP-K12). Each conjugate is injected i.t. and undergoes an LCST phase transition at body temperature to form ELP depots. The 131I is retained within the tumor because of radiation-induced crosslinking of the ELP and irradiates the tumor from the inside-out, while the electrostatically complexed CpG is released from the depot over time to activate immune signaling within the tumor.