TABLE 2.

Design of C-terminal TCHE tags on B41 SOSIP.v4.1 trimers^a

^aTT, tetanus toxoid; DpT, diphtheria toxoid. The GS-rich spacer is in black, cathepsin S cleavage sites are highlighted in yellow, TCHE sequences are in magenta, and additional lysine residues are in red. Cathepsin S is a lysosomal protease active in the pH range from 6 to 7.5; the cleavage site is intended to allow the TCHE sequence to be liberated from the trimer and, by extension, the trimer IO-NP. The KK motif was added as an early strategy, not further pursued, to provide a preferential point of trimer attachment to IO-NPs.