Chitosan with low molecular weight

Chitosan with low molecular weight (50–190 kDa based on viscosity, 75–85% deacetylated) and sodium tripolyphosphate were purchased from Sigma–Aldrich (St. Louis, MO, USA). d(+)‐trehalose dehydrate (99%) and FITC, isomer 1 (95%), were purchased from Alfa Aesar (Tewksbury, MA, USA). Trehalose assay kit was purchased from Megazyme (Wicklow, Ireland). Eagle's minimum essential medium (α‐MEM), Roswell Park Memorial Institute (RPMI)‐1640 medium, horse bovine serum, 2‐mercaptoethanol (2‐mer, 50 × 10⁻³m), and penicillin and streptomycin were purchased from Gibco (ThermoFisher Scientific, USA). Myo‐inositol and folic acid were purchased from Sigma–Aldrich (St. Louis, MO, USA). FBS and DMSO were purchased from Corning (New York, NY, USA). Recombinant human IL‐2 (rhIL‐2) was gifted from Akron Biotech (Boca Raton, FL, USA). The CCK‐8 assay kit was purchased from Glpbio (Montclair, CA, USA). The CFSE/7‐AAD kit was purchased from Cayman Chemical (Ann Arbor, MI, USA). All the antibodies including PerCP‐Cy5.5‐conjugated IFN‐γ antibody (clone B27), phycoerythrin (PE)‐conjugated‐CD107a antibody (clone H4A3), GolgiStop solution, Cytofix/Cytoperm solution, and Perm/Wash buffer were purchased from BD Biosciences (San Jose, CA, USA). All other chemicals were purchased from Sigma, unless specifically noted otherwise.