NK and T-cell markers on H-2^k– and H-2^b–derived IL-2 and IL-2/IL-12 A-LAK populations. Flow cytometric analysis of (A) AKR (H-2^k), (B) C57BL/6 (H-2^b), and (C) B10.BR (H-2^k)–derived IL-2 versus IL-2/IL-12 A-LAK preparations, stained with FITC (Y axis) and PE (X axis)–labeled MoAbs as described in Materials and Methods. The cells were preincubated with 2.4G2 for 30 minutes before staining. The results are represented in dot plots indicating the percentage of positive cells. Positive populations were calculated via quadrant statistics applying the proper isotype controls to outline the negative populations (top panels represent FITC-labeled rat IgM and PE-labeled syrian hamster Ig, other isotype controls are not shown).