Fig. 2

The shared ligands oAβ and PS induce co-ligation of LILRB2 and TREM2 and inhibit TREM2 signaling. a. Schematic illustration of the cell line LILRB2-TREM2 showing the design of BiFc assay with LILRB2 and TREM2 fusion constructs. b-c. oAβ or PS-induced co-ligation of TREM2 and LILRB2 as measured by the BiFc assay. HEK293T cells co-expressing LILRB2-N173 Venus and TREM2-C155 Venus were incubated with plate-coated oAβ (b) or PS (c). Y-axis shows the MFI signals from complemented Venus. Data are presented as mean ± SD (n = 3 independent experiments). d. Representative immunofluorescence images showing oAβ-lipid-induced co-ligation of TREM2 and LILRB2. Scale bar represents 5 μm. e. Schematic diagram showing co-ligation of LILRB2 and TREM2 by oAβ or PS inhibits TREM2 signaling in reporter cell assays. The ITIM motifs of LILRB2 attenuate signaling generated by ITAM motifs of TREM2 upon cross-linking by shared ligands oAβ or PS. f-g. oAβ or PS-induced TREM2 signaling of reporter cells co-expressing LILRB2 and TREM2. Reporter cells expressing corresponding receptors (x-axis) were incubated with oAβ (f) or PS (g). Y-axis is TREM2 signaling of treatment groups normalized based on the percentage of GFP⁺ reporter cells expressing only TREM2 (set to 100%). Data are presented as mean ± SD (n = 4 independent experiments). h. oAβ-lipoprotein complex phagocytosis profile of BV2 cells expressing the LILRB2 transgenes (x-axis). BV2 cells were incubated with FAM-oAβ-lipoprotein complex. Phagocytosis was quantified by flow cytometry, with the MFI shown. Negative phagocytosis control included 10 μM CytoD together with indicated treatments. Data are presented as mean ± SD (n = 4 independent experiments)