Effect of autologous MD-DCs on survival and activation of rIL-2–deprived NK/LAK cells.

Autologous MD-DCs sustain survival and activation of rIL-2–deprived NK/LAK cells. NK/LAK cells with or without MD-DCs were cultured at a 1:1 E/T ratio for 7 days in RPMI 1640 with 10% human AB serum without IL-2 at 1 × 10⁶ cells per milliliter. (A) At days 3, 5, and 7, viable lymphocytes were counted after trypan blue exclusion of dead cells, and mean ± SEM (n = 7) percentages of CD56⁺CD3⁻ NK/LAK cells were determined by flow cytometry. Survival values were determined as the percentages of live CD56⁺CD3⁻ total numbers at days 3, 5, and 7 compared with day 0. In comparison, mean ± SEM (n = 3) survival percentages of NK/LAK cells alone left in culture with IL-2 (1000 IU/mL) is reported. (B) Cytotytic activity of day-7 cocultures of bulk NK/LAK cells (n = 10) or CD3⁻ and CD3⁺ immunopurified subsets (n = 3, inset) with or without MD-DCs. Results are presented as mean ± SEM percentages of lysis at a 6.25:1 E/T ratio against K562 (white bars), Daudi (gray bars), and NB1 (black bars). (C) Immunophenotyping of cocultures was performed by 4-color flow cytometry with the use of the combination of FITC-, PE-, PerCP-, and APC-conjugated mAbs CD16/CD56/CD3/CD45. One representative experiment showing the persistence of CD3⁻CD56^brightCD16⁺ NK/LAK cells in a day-7 coculture with MD-DCs is presented.