maintained in T cell Serum-free Medium (STEMERY, RC-
003-500) supplemented with 20 ng/ml rh-IL-2 (Biolegend, 589102),
100 U/ml penicillin, and 100 μg/ml streptomycin and activated
with 5 μg/ml plate-coated CD3 antibody (eBioscience, 16-0037-
85) and 2 μg/ml free CD28 antibody (eBioscience, 16-0037-28).
Jurkat cells were incubated in RPMI 1,640 supplemented with
10% exosome-free fetal calf serum (System Biosciences, Catalog
NO. EXO-FBS-50A-1) and activated with CD3 and CD28. Human
oral keratinocytes were cultured in K-SFM (Gibco, 10744019) and
pretreated with 10 ng/μl lipopolysaccharide (LPS) for 24 hr before
experiments.