Figure 5. Cationic liposome encapsulated antigen when mixed with TLR agonist superiorly elicits stronger CD8⁺ T-cell response.

(a,c) Representation of the in vitro and in vivo experimental setups, respectively. (b) Enriched BMDCs were stimulated with 2.5 μg of rgp63 free, entrapped in liposomes or liposomal rgp63 mixed with MPL-TDM. BMDCs stimulated with empty cationic liposomes (CL; 100 μM) or with only MPL-TDM (MPL; 100 ng/ml) or with only rgp63 + only MPL-TDM (rgp + MPL-TDM) served as controls. After 18 h 1 × 10⁴ BMDCs were co-cultured with 1 × 10⁵ CD4⁺ T/CD8⁺ T cells isolated from mouse immunized with lrgp + MPL-TDM (for detail see “Materials and Methods” section). After 4 days of culture, T- cell proliferation was measured by thymidine uptake. (d) BALB/c mice were injected subcutaneously on day 0 and 14 with cationic liposomes (CL; 100 μM), 2.5 μg free rgp63 (rgp), liposomal rgp63 alone (lrgp) or mixed with MPL-TDM (lrgp + MPL). On day 5, after the final immunization draining lymph nodes were removed. The LN cell suspensions were prepared, and the CD8⁺ T cells were purified magnetically using MACS. 1 × 10⁵ CD8⁺ T cells were incubated with 1 × 10⁴ BMDCs (10:1 ratio) that had been incubated with lrgp + MPL for 18 h. T cell proliferation was measured on day 4. Data represent mean CPM × 10³ ± SE of triplicate cultures. *p < 0.05, **p < 0.01 ***p < 0.001, analyzed by one-way ANOVA followed by Tukey’s multiple comparison tests.