Figure 5.

Activation of OT-I and OT-II cells through MHC-I and MHC-II mediated antigen presentation pathways, respectively. BMDCs were incubated with OVA (fc: 25 μg/mL)-loaded cationic liposomes (fc: 25 μM) or the same concentration of soluble OVA, or the same concentration of liposomes for 2 hrs, and then extracellular OVA or liposomes were washed off with DPBS. CFSE was used to label splenocytes from OT-I mice (A, C, E) or OT-II mice (B, D, F) and then labeled cells were added into the BMDC culture plate. The supernatant was partially collected after overnight incubation to detect the secretion of IL-2 using an ELISA kit (A, B); and the cells were collected after 48 hrs incubation to analyze the OT-I cell and OT-II cell division using flow cytometry (C, D, E, F, see gating strategies of OT-I and OT-II cells in Figure S5). (−) Lipo indicates the BMDCs without treatment [(−) OVA] or treated with soluble OVA [(+) OVA]; other experimental groups were treated with naked liposomes [(−) OVA], or OVA-loaded liposomes [(+) OVA]. Data show the mean+SD of two independent experiments with two replicates, respectively; *P<0.05, **P<0.01.

Abbreviations: BMDCs, bone marrow-derived dendritic cells; OVA, ovalbumin; CFSE, carboxyfluorescein succinimidyl ester.