IL-12 gene transduction of bystander cells increases local infiltration of NK cells and DCs.

BALB/c mice were injected intraperitoneally with 10⁶ live A20 cells. The following day, mice were intraperitoneally vaccinated with the indicated irradiated cell tumor vaccines. On day 3 after vaccination, peritoneal exudate cells (PECs) were collected, counted, and analyzed by FACS for DC (■) and NK (▪) infiltration (main graph). PECs were also evaluated for NK activity in a 4-hour⁵¹Cr release assay against YAC target cells. PECs were from mice vaccinated with the following: A20 cells (♦), A20 plus B78H1 cells (▪), A20 plus B78H1–IL-12⁴⁰⁰ cells (▴), and A20 plus B78H1–IL-12²⁵⁰⁰⁰ cells (✖). Three individual mice were analyzed in each group.