Presence of IL-12 during LAK cell production generates an adherent subpopulation with a specific morphotype. In contrast to IL-2 LAKs (A), IL-12 induces the formation of granulous, large cells (B). Adherent AKR-derived LAK cells were stained with Crystal violet and photographed (original magnification × 100) in culture plate. This morphological shift can also be visualized by FACS scatter analysis of AKR-derived IL-2 A-LAK cells (C) as compared with IL-2/IL-12 A-LAK cells (E). The population with highest cellular density is situated in region 1 (R1) for IL-2 A-LAK and in region 2 (R2) for IL-2/IL-12 A-LAK. The overlay histogram (D) compares the side scatter signals of both LAK populations.