CD44^hiCD8⁺ and CD44^loCD8⁺ T cells proliferate and produce similar levels of cytokines in vivo. (A) C3H.SW CD44^loCD8⁺ T cells were stimulated with B6 DC plus IL-2 plus IL-15. Five days later, these unseparated B6 DC-induced T cells were restimulated with anti-CD3 Ab for 16 hours and the production of intracellular cytokines IFN-γ, IL-2, IL-4, IL-10, and TNF-α was analyzed by flow cytometry prior to infusion. Numbers in quadrants represent percentages of total cells in each cell fraction. (B,D) CD44^hiCD8⁺ and CD44^loCD8⁺ T cells were sorted from the B6 DC-stimulated T-cell cultures at day 5 and labeled with CFSE. Then, 1 × 10⁶ of these B6 DC-stimulated CD44^hiCD8⁺ or CD44^loCD8⁺ T cells (CD45.2) were mixed with 5 × 10⁶ B6 T^-BM (CD45.1) and transplanted into lethally irradiated B6 mice. Lymphocytes were recovered from the spleens these B6 recipient mice at the indicated time points after transplantation for measuring the production of intracellular cytokines (B) and phenotype (D). Numbers in quadrants represent percentages of each cell fraction. (C) The ratio of CD44^hiCD62L^lo/CD44^hiCD62L^hi T cells among DC-induced CD44^loCD8⁺ T cell subsets prior to infusion or donor CD8⁺ T cells recovered from the spleens of a group of 3 mice receiving CD44^hiCD8⁺ and 3 mice receiving CD44^loCD8⁺ T cells was calculated based on the number of donor CD8⁺ T cell–derived CD44^hiCD62L^lo and CD44^hiCD62L^hi T cells. All values represent means ± SD. Data shown are the representative of 3 independent experiments.