Vero e6 cells

Human monocytic leukemic cell line THP-1 (Korean Collection for Type Cultures, KCTC; Jeongeup-si, Jeollabuk-do, Korea) was cultured in RPMI1640 medium (Welgene, Republic of Korea) supplemented with 10% fetal bovine serum (FBS, Gibco, USA), 1% penicillin/streptomycin (P/S), and 0.5 nM 2-mecaptoethanol. THP-1 monocytes were differentiated into Mɸs by treating with 25 nM PMA for 48 h prior to polarization. Human CD14⁺ monocytes (PromoCell, Heidelberg, Germany) were cultured with 50 ng/mL of GM-CSF or M-CSF for seven days to achieve differentiation. All Mɸs were polarized in vitro with either LPS (20 pg/mL; Invitrogen, USA) and IFN-γ (20 ng/mL) or IL-4 (20 ng/mL) and IL-13 (20 ng/mL) (Peprotech, USA) for 24 h. Cells were washed thrice with phosphate-buffered saline (PBS) to remove any remaining cytokines. Human PBMCs were purchased from Cellular Technology Limited (CTL; OH, USA). Vero E6 cells were purchased from KCTC and maintained in minimal essential medium (MEM; Welgene, Daejeon, Korea) supplemented with 10% FBS and 1% P/S.