*2.1. Materials and Reagents*

The RPMI-1640 medium, Dulbecco's modified essential medium with high glucose (DMEM) were purchased from HyClone Co. (Logan, UT, USA), while the fetal bovine serum (FBS) was provided by Thermo Fisher Scientific Inc. (Cleveland, OH, USA). Both neutral red and trypan blue were purchased from Amresco Inc. (Los Angeles, CA, USA), and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT), concanavalin A (ConA), and lipopolysaccharide (LPS) were provided by Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). The phosphate-buffered saline (PBS) was the product of Solarbio Science and Technology Co. Ltd. (Beijing, China), while the Hanks' balanced salt solution (HBSS) and the red blood cell lysis buffer were obtained from Beyotime Biotechnology (Beijing, China). The cell counting kit-8 (CCK-8) was the product of Dojindo Laboratories (Kyushu, Japan). Ultrapure water generated from Milli-Q Plus (Millipore Corporation, New York, NY, USA) was used in this study. Other chemicals used in the present work were of analytical grade.

The phycoerythrin (PE)-conjugated anti-mouse CD8a+ antibodies and fluorescein isothiocyanate (FITC) anti-mouse CD4<sup>+</sup> antibodies were bought from Miltenyi Biological Technology Co. Ltd. (Bergisch Gladbach, Cologne, Germany), while the enzyme-linked immunosorbent assay (ELISA) kits [mouse interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-4, IL-6, and tumor necrosis factor-α (TNF-α)] were bought from Boster Biological Engineering Co. Ltd. (Wuhan, China).

#### *2.2. Animal and Cells*

The used mice (female BALB/c, 6–8 weeks old) in this study were provided by professional institution Beijing Vital River Experimental Animal Technical Co. Ltd. (Beijing, China). As usual, the mice were maintained for at least 7 d before the experiments performed at Northeast Agricultural University (Harbin, China). In addition, all animal procedures were approved and instructed by Animal Care and Use Committee of Northeast Agricultural University.

The used RAW 264.7 macrophages, provided by Shanghai Branch of Chinese Academy of Sciences (Shanghai, China), were incubated in the DMEM medium supplemented with 10% fetal bovine serum (FBS) and 100 U/mL streptomycin/penicillin. The cells were cultured in an incubator of 37 ◦C and 5% CO2 referring to the recommendation of cell supplier.
