Apoptotic mechanism on sorted Gr-1⁺ cells from bone marrow cultures of Balb/c and C57BL/6-KO CD16 mice. (A) Fresh BM cells were stained with Gr-1(PE), CD2(FITC), and 6B2(FITC). A granulocyte gate was used based on the orthogonal and forward scatter to perform the sorting. Gr-1⁺ CD2⁻, 6B2⁻ cells were collected postsorting. (B) Apoptotic analysis of sorted Gr-1⁺ cells on Balb/c and C57BL/6-KO CD16 mice. Sorted cells (2 × 10⁵/mL) were cultured for 24 hours with rGM-CSF, rIL-3, and rIL-5 in the presence of 2.4G2 (25 μg/mL). Annexin-V and fas expression were analyzed. The cursor was placed to compare the cultures with cytokines alone or in combination with 2.4G2. (C) RT-PCR analyses of FcγR were performed on sorted Gr-1⁺ population (1 × 10⁶ cells). Arrow shows 600-bp standard in the 100-bp ladder. FcγRIIβ1 and β2 transcripts correspond to the bands at 477 and 339 bp, respectively.