FIGURE 3.

Endometriotic tissue–derived NKG2D ligand-carrying exosomes (exo) impair the killing ability of PBMCs from healthy donors. (A) NKG2D-mediated cytotoxicity was assessed with PBMCs as effector cells and the erythroleukemia cell line K562 as target cells (E:T ratio 40:1) in the presence/absence of native or mAb-blocked endometriotic tissue exosomes (n = 4). Note that the presence of native exosomes reduced the cytotoxicity to a degree comparable to blocking the target or effector cells (p = 0.0001). Treatment of the exosomes with a mAb mixture of NKG2D ligands or anti-CD63 mAb reversed the suppression to nonsignificant levels, compared with untreated target and effector cells. Used supernatant, left after isolation of exosomes, did not affect cytotoxicity. (B) Experiments similar to those in (A) with exosomes isolated from serum from endometriosis patients (n = 3). (C) Experiments similar to those in (A) with exosomes from healthy donors (n = 6).