(A) Screening for homologous recombination by Southern blot of NcoI digested DNA. WT allele:10kb. Disrupted allele:6.5kb. Targeting vector and locus are shown in Figure S3A. (B) Surface CD84 expression on WT and Cd84−/− splenic B cells. (C) Top panel: thymocytes stained with α-CD4 and α-CD8. Middle panel: thymocytes stained with CD1d-αGalCer tetramers, α-CD4, α-CD24, and α–TCRβ to evaluate NKT cells. Bottom panel: splenocytes stained with α-CD19 and α-CD4 (n=3, 3 mice/genotype). (D) WT and Cd84−/− T cells were stimulated with α-CD3+/− α-CD28 and evaluated for proliferation and (E) IL-2 and IFN-γ production (n=3). (F) WT and Cd84−/− B cells were stimulated for 48 h with LPS, α-IgM, or α-CD40 and evaluated for proliferation (n=4). (G) WT, Sh2d1a−/−, and Cd84−/− mice were immunized with the type II T-independent antigen, NP-Ficoll, and assessed for NP-specific antibody production, day 21 (n=2, 5 mice/genotype).