Figure 6. Differentiation and development of memory CD3⁺CD8⁺ subsets upon repeated stimulation with a cocktail of XBP1 UN_185-193 (I S P W I L A V L), XBP1 SP_223-231 (V Y P E G P S S L), CD138_265-273 (I F A V C L V G F) and CS1_240-248 (L F V L G L F L W) peptides.

The Naïve:Memory CD3⁺CD8⁺ CTL subsets were characterized following each round of stimulation with HLA-A24 multipeptide cocktail. Repeated multipeptide stimulation of CD3⁺ T cells from HLA-A24⁺ donors (N=5) induced phenotypic changes from naïve (CD45RO⁻CCR7⁺) CD3⁺CD8⁺ T cells into central memory (CD45RO⁺ CCR7⁺) CD3⁺CD8⁺ T cells after 2 cycles of peptides stimulation and then into effector memory (CD45RO⁺ CCR7⁻) CD3⁺CD8⁺ T cells after 3 cycles of stimulation (Figure 6A), and then into effector memory (CD45RO⁺ CCR7⁻) CD3⁺CD8⁺ T cells after 4 cycles of stimulation (Figure 6B). Within the multipeptide-specific CTL population, the central memory subset expressed the highest levels of critical activation and co-stimulatory T cell markers (CD38, CD69, CD40L, 41BB; Figure 6C)