(A) Ly-6C^hi monocytes from the spleens of apoE^–/– mice were placed into culture with medium alone or medium supplemented with 100 μg/ml AcLDL or 50 μg/ml M-CSF. The percentage of cells alive 24 hours later was calculated based on the ratio of retrieved and input cell numbers. **P < 0.01, *P < 0.05 versus medium alone (1-way ANOVA with Tukey’s multiple comparison test). (B) apoE^+/+ and apoE^–/– mice on chow and Western diet received 3 i.p. injections of BrdU on 3 consecutive days. Cells from bone marrow, blood, and spleen were collected 1 day after the last injection and labeled with annexin V or anti-BrdU mAb. Results are shown for gated CD11b^hiCD90^loB220^loCD49b^loNK1.1^loLy-6G^lo monocytes as identified in Figure 1. Statistical analyses were performed using Student’s t test. (C) Representative dot plots depicting annexin V staining and BrdU incorporation in splenic CD11b^hiCD90^loB220^loCD49b^loNK1.1^loLy-6G^lo monocytes from apoE^+/+ and apoE^–/– mice on chow and Western diet. (D) apoE^–/– mice on chow and Western diet received clodronate liposomes on day 0. Representative contour plots depict Ly-6C versus F4/80/I-A^b/CD11c phenotype among splenic CD11b^hiCD90^loB220^loCD49b^loNK1.1^loLy-6G^lo monocytes on days 1 and 5 or in age-matched untreated mice. (E) Percent of splenic Ly-6C^lo monocytes recovered after clodronate liposome injection in apoE^–/– mice on chow and Western diet compared with absolute number of cells in age-matched untreated mice. Shown are 1 of 2–3 independent experiments.