Fig 1: Reactivity of VER and RIF antibodies Exogenous expression of SLC44A2 in L‐929 cells results in cell surface expression of the VER antigen. L‐929 cells stably transfected with pcDNA3.1/SLC44A2 full‐length cDNA (red) or with cDNA3.1/SLC44A2(1192A) (blue) and then analyzed by flow cytometry with anti‐VER antibody. The green profile corresponds to untransfected L‐929 (wild‐type), and the light gray profile corresponds to wild‐type cells incubated with only the secondary antibody.Western blotting shows that the anti‐RIF and anti‐VER antibodies bind to HuSLC44A2. Western blots of whole Sf9 lysates (WCL) expressing full‐length recombinant human SLC44A2 cDNA (rHuSLC44A2) were probed with RIF and VER antisera (1:10). Lanes 1 and 2 show strong binding to rHuSLC44A2. Titer differences in the sera required longer exposure (10 min) of the filter to the film to develop the image with VER serum compared with only 30 s exposure for RIF serum. A similar blot of immunoprecipitated rHuSLC44A2 from the Sf9 lysates similarly reacted with RIF and VER sera (lanes 3 and 4) showed equivalent exposure times (30 s for both sera) when tested against the concentrated rHuSLC44A2 protein.The anti‐RIF and VER antibodies bound to immunoprecipitated wild‐type SLC44A2 in lysates of the UM‐SCC‐47 human squamous cancer cell line (exposure time 5 min).Western blot of murine Slc44a2 protein immunoprecipitated from wild‐type and Slc44a2 knockout mice with rabbit anti CTL2‐NT serum was probed with anti CTL2‐NT (left panel) and with VER serum (center Panel) or RIF serum (right panel). The left panel was developed with goat anti rabbit IgG heavy and light chain (Bethyl Lab cat # A120‐113P); the center and right panels were developed with rabbit anti human IgG and IgM heavy and light chain specific (Jackson Immunochemicals cat # 309035107). Source data are available online for this figure.