For the isolation of macrophages and neutrophils from milk and blood, total somatic cells were isolated from 50-mL milk samples as above, and total blood leukocytes were collected from 1 mL of heparinized blood by hypotonic lysis of erythrocytes. Cells from milk and blood were then incubated for 30 min on ice with allophycocyanin- conjugated anti-CD14 (Tuk4 clone, Life Technologies) and fluorescein isothiocyanate-conjugated mouse anti-bovine CD11b (CC126 clone; AbD Serotec, Raleigh, NC) in 100 μL of PBS containing 0.5% bovine serum albumin (Fisher Scientific, Fair Lawn, NJ) and 2 mM EDTA (Fisher Scientific). Cells were then sorted on the basis of size, granularity, and intensity of fluorescein isothiocyanate and allophycocyanin fluorescence as previously described (Merriman et al., 2017) using a Sony SH800 cell sorter equipped with 405-, 488-, and 633-nm lasers (Sony Biotechnology Inc., San Jose, CA). The CD11b+CD14+ cells were considered milk macrophages or blood monocytes, and CD11b+CD14− cells were considered neutrophils. At least 10,000 CD11b+CD14+ cells and 50,000 CD11b+CD14− cells from each sample were collected with >95% purity. The sorted cells were then pelleted and lysed with RNA lysis buffer from Quick-RNA MiniPrep (Zymo Research, Irvine, CA) for later RNA isolation.