Effects of N-acetyl chitooligosaccharides (NACOS) on production of nitric oxide (NO), reactive oxygen species (ROS), gene expression of iNOS and NOX2, and phagocytosis of RAW264.7 cells. Cells were treated with NACOS (100 µg/mL) or lipopolysaccharide (LPS) (1 µg/mL). (A) NO production following treatment with NACOS for 24 h. (B) Expression of the iNOS gene following treatment with NACOS for 8 h. (C) ROS production following treatment with NACOS for 4 h. (D) Expression of the NOX2 gene following treatment with NACOS for 4 h. (E) Phagocytosis of beads by RAW 264.7 cells, as detected by flow cytometry, following treatment with NACOS for 24 h. Only the control (Ctrl), LPS, and NACOS6 treatments are shown (chitosan oligosaccharides (COS) and NACOS1–5 are presented in Supplementary Figure S3). (F) Histogram of phagocytosis rates following treatment with NACOS. Data were normalized to that of β-actin and presented as the fold induction compared with the control group. Values are presented as the mean ± SD (n = 3). (* p < 0.05; ** p < 0.01; *** p < 0.001, compared with the control group).