Fig. 2.
Monoglycerides do not induce cell death in total PBMCs, in major leukocyte populations, or in activated PBMC subsets from healthy individuals.
(A) (Left panel) T-leukemic Jurkat cells or total normal PBMCs were incubated for 3 hours with the vehicle (Ctrl; white bars) or 80 μM 1-C18:1 monoglyceride (MG; black bars). After treatment, cells were stained with annexin V. (Right panel) Normal PBMCs were stimulated with the vehicle (Ctrl; white bars) or 80 μM 1-C18:1 monoglyceride (MG; black bars). After a 3-hour incubation period, the samples were stained for cell surface molecules (anti-CD4 and anti-CD8, anti-CD20 and anti-CD5, anti-CD56 and anti-CD3, or anti-CD14) and annexin V and analyzed by flow cytometry. Electronic gating was performed to determine the percentage of dying cells in distinct leukocyte populations: namely, T helper cells (Th; CD4high), T cytotoxic cells (Tc; CD8+), conventional B cells (Bc; CD20+CD5−), B-1a B cells (BB-1a; CD20+CD5+), natural killer cells (NK; CD56+CD3−), or monocytes (Mono; CD14+). (B) Normal PBMCs were stimulated for 48 hours with either phytohemagglutinin (left panel) or lipopolysaccharides (right panel). Fresh and activated PBMCs were cultured for 3 hours with the vehicle (Ctrl; gray and hatched bars, respectively) or 80 μM 1-C18:1 monoglyceride (MG; white and black bars, respectively). (Left panel) A 4-color staining was performed with anti-CD69 (early activation marker), anti-CD8, anti-CD4, and annexin V. Using electronic gating, sensitivity to monoglyceride-induced cell death was assessed in resting (total CD69− PBMCs, CD4highTh, and CD8+ Tc; gray and white bars) and activated (total CD69+ PBMCs, CD4highTh, and CD8+ Tc; hatched and black bars) populations. (Right panel) A 3-color staining was performed with anti-CD69, anti-CD20, and annexin V to detect cell death among resting (total CD69− PBMCs and Bc[CD20+]; gray and white bars) and activated (total CD69+ PBMCs and Bc [CD20+]; hatched and black bars) cells. Results are shown as mean percentages of annexin V–positive cells ± SD from triplicates. Similar results were obtained from 3 different healthy donors.