Establishment of the LILRA3-overexpressing U937 cell line
The open reading frame (ORF) of LILRA3 was amplified from U937 cells using qRT-PCR and cloned into the expression vector pWSLV-02 (carrying enhanced green fluorescent protein (EGFP) as a reporter gene) (Viewsolid, Beijing, China) to generate the plasmid pWSLV-02-LILRA3. For lentivirus production, 293T cells were co-transfected with the pWSLV-02-LILRA3 plasmid, which encodes the intact sequence of LILRA3 cDNA, or the empty vector pWSLV-02 as a control using Lenti-Pac HIV Expression Packaging Kit (GeneCopoeia, Rockville, USA). Virus was collected at 24 hours and 48 hours after transfection. To prepare the LILRA3-overexpressing cell line, U937 cells were infected with lentivirus for 72 hours, and FCM was then used to select cells with stable LILRA3 lentivirus integration.