Archaeosome Adjuvant Overcomes Tolerance to Tumor-Associated Melanoma Antigens Inducing Protective CD8+ T Cell Responses
Figure 6
Optimized induction of CD8+ T cell response to dual melanoma antigen vaccine. Mice were vaccinated (days 0 and 21) with 30 μg of individual peptide-archaeosome vaccines or in an admixed formulation containing 30 μg of each peptide. At 4 weeks, representative mice ( per group) were euthanized, the spleen cells were stimulated with IL-2 (0.1 ng/mL) and each peptide (5–25 μg/mL) for 48 h, and the frequency of IFN-gamma secreting cells was enumerated by ELISPOT. Mean ± SD () of IFN-gamma secreting cells per 106 spleen cells is indicated for TRP-peptide (a) and Gp100 peptide (b) stimulation. The percentage of tetramer-specific CD8+ T cells was enumerated in the blood on day 28. Representative plots for the various groups are shown (c), and the Mean ± SD () of the response is indicated within each panel. In vitro CTL response in representative mice () vaccinated with the admixed formulation was evaluated on day 28 against EL-4, EL-4-TRP, and EL-4-Gp100 targets (d). Mean ± SD at 100 : 1 effector : target ratio is indicated. At 4 or 6 weeks postvaccination, mice ( per group) were challenged with B16 melanoma (e). Survival curves for the vaccinated groups were significantly different from naïve by log-rank test (). Archaeosome loadings were 40 μg Gp100/mg and 20 μg TRP/mg lipid. Archaeosome size ranged from 110 to 117 nm.
