LAK cells differentially lyse M1 versus M2 cells.

The activity of (A) IL-2– or (C) IL-2/IL-12–activated LAK cells was measured in an in vitro cytotoxicity assay. (A) IFN-γ–treated RAW 264.7 (♦) and IL-4/IL-10–treated RAW 264.7 (●) cells were tested for their susceptibility to LAK lysis. (B) Production of NO (▪) and arginase activity (■) in IFN-γ– or IL-4/IL-10–treated Raw264.7 cells. Results are expressed as quantities detected per milligram protein level. (C) Sensitivity of adherent cells, isolated from spleen cells cultured during 5 days in vitro, to LAK effector cells. Spleens were isolated from BW-Sp3 tumor-bearing AKR mice 6 days after tumor injection (♦) and from α-ASGM-1–treated, BW-Sp3 tumor–bearing AKR mice 6 days after tumor injection (●). Spontaneous release was 10% or less for RAW 264.7 cells and 17% or less for splenocytes. For panels A and C one representative experiment of 2 is shown, indicating the mean percentages of specific release of targets in triplicate (± SEM). SEM of less than 3% are not shown for clarity.