Interleukin‑2 Functionalized Nanocapsules for T Cell-Based Immunotherapy

A major demand on immunotherapy is the direct interference with specific immune cells <i>in vivo</i>. In contrast to antibody-engineered nanoparticles to control dendritic cells function, targeting of T cells for biomedical applications still remains an obstacle as they disclose reduced endocytic activities. Here, by coupling the cytokine interleukin-2 (IL-2) to the surface of hydroxyethyl starch nanocapsules, we demonstrated a direct and specifc T cell targeting <i>in vitro</i> and <i>in vivo</i> by IL-2 receptor-mediated internalization. For this purpose, defined amounts of azide-functionalized IL-2 were linked to alkyne-functionalized hydroxyethyl starch nanocapsules <i>via</i> copper-free click reactions. In combination with validated quantification of the surface-linked IL-2 with anthracen azide, this method allowed for engineering IL-2-functionalized nanocapsules for an efficient targeting of human and murine T cell populations with various IL-2 receptor affinities. This nanocapsule-mediated technique is a promising strategy for T cell-based immunotherapies and may be translated to other cytokine-related targeting systems

Chemoselective Dual Labeling of Native and Recombinant Proteins

The attachment of two different functionalities in a site-selective fashion represents a great challenge in protein chemistry. We report site specific dual functionalizations of peptides and proteins capitalizing on reactivity differences of cysteines in their free (thiol) and protected, oxidized (disulfide) forms. The dual functionalization of interleukin 2 and EYFP proceeded with no loss of bioactivity in a stepwise fashion applying maleimide and disulfide rebridging allyl-sulfone groups. In order to ensure broader applicability of the functionalization strategy, a novel, short peptide sequence that introduces a disulfide bridge was designed and site-selective dual labeling in the presence of biogenic groups was successfully demonstrated