CD160-Derived Peptide as a Bidirectional Inhibitor Toward Immune Checkpoints BTLA/HVEM and HVEM/LIGHT

BTLA and HVEM are key immune checkpoint proteins involved in regulating immune responses. Since HVEM also binds to CD160 at a site that overlaps with the BTLA binding site, CD160-derived fragments were used to design peptide inhibitors targeting this interface. Several peptides were synthesized and assessed for HVEM binding using SpS analysis, and their inhibitory activity was evaluated in ELISA and cell-based assays. One peptide, namely A5, demonstrated strong HVEM binding and effectively blocked the BTLA/HVEM interaction. Molecular docking results revealed that peptide A5 binds to HVEM not only at the BTLA interaction site but also at the region involved in LIGHT binding. Consistent with these findings, ELISA and cell-based assays confirmed that A5 effectively disrupts both BTLA/HVEM and HVEM/LIGHT complex formation. These results suggest that A5 acts as a dual inhibitor of HVEM interactions, with potential therapeutic implications for immune-related disorders.