To gain insight into the developmental relationship and functions of CD16+ and CD16- Monocytes

Total Mo were isolated by negative selection using magnetic immunobeads (Monocyte Isolation Kit II, Miltenyi). CD16+ and CD16- Mo fractions were further isolated using CD16 magnetic immunobeads (Miltenyi). Total RNA from Mo pellets was isolated by Trizol extraction and purified using RNeasy columns (Qiagen). The quality of RNA was assessed by visualization of intact bands corresponding to 18S and 28S rRNA on formaldehyde agarose gels. Total RNA (10 µg) from matched CD16+ and CD16- Mo samples isolated from 4 different healthy donors was quality tested using an Agilent 2100 Bioanalyzer chip, reverse transcribed, and hybridized on the GeneChip Human Genome U133 Plus 2.0 Array (Affymetrix), which includes 54,000 probe sets on a single array (i.e., 47,000 transcripts and variants, including 38,500 well-characterized human genes). Primary data analysis performed using GeneSpring software (Biopolymer core facility, Harvard Medical School) generated Excel spreadsheets with relative gene expression values for the 4 matched CD16+ and CD16- Mo subsets.