LFA-1 interaction with GBP-130 on <i>Plasmodium falciparum</i>-infected red blood cells mediates NK cell activation and parasite control

Natural killer (NK) cells contribute to early immunity against Plasmodium falciparum by recognizing and eliminating infected red blood cells (iRBCs), a process mediated in part by the integrin LFA-1. However, the cognate parasite ligand for LFA-1 has remained unknown. Here, we identify glycophorin binding protein-130 ( Pf GBP-130) as a surface-expressed ligand on iRBCs that binds the I-domain of LFA-1 (LFA-1 αI). Using an LFA-1 αI-Fc fusion protein, we demonstrate stage-specific binding to iRBCs, and LC-MS/MS analysis of immunoprecipitates of αI-Fc bound to iRBC revealed Pf GBP-130 as a high-confidence interactor. Recombinant Pf GBP-130 binds NK and THP-1 cells in an LFA-1-dependent manner. Co-culture assays show that Pf GBP-130 promotes NK cell activation and degranulation and facilitates contact-dependent killing of iRBCs. Neutralizing antibodies against Pf GBP-130 significantly impair these responses. Our findings establish Pf GBP-130 as the LFA-1 ligand on iRBCs, providing new insi