Bioengineering mini functional thymic units with EAK16-II/EAKIIH6 self-assembling hydrogel

• Generation of mini clusters of TECs with self-assembling EAK16-II/EAKIIH6 hydrogel.
• TEC/EAK mini clusters can retain the molecular properties of TECs in vitro.
• TEC/EAK mini clusters can support T-cell development in athymic nude mice.
• The TEC/EAK system might be used to generate injectable mini thymus units.

Herein, we highlight the technical feasibility of generating a functional mini thymus with a novel hydrogel system, based on a peptide-based self-assembly platform that can induce the formation of 3-D thymic epithelial cell (TEC) clusters. Amphiphilic peptide EAK16-II co-assembled with its histidinylated analogue EAKIIH6 into beta-sheet fibrils. When adaptor complexes (recombinant protein A/G molecules loaded with both anti-His and anti-EpCAM IgGs) were added to the mix, TECs were tethered to the hydrogel and formed 3-D mini clusters. TECs bound to the hydrogel composites retained their molecular properties; and when transplanted into athymic nude mice, they supported the development of functional T-cells. These mini thymic units of TECs can be useful in clinical applications to reconstitute T-cell adaptive immunity.