CD38/CD31 cross-talk induces CD38/CD19 lateral association within lipid rafts. (A) Representative images of cocapping experiments between CD38 and CD19 or CD81 in tonsillar B lymphocytes. When indicated, cells were pretreated with MβCD, a cholesterol-chelating agent used to disrupt the rafts. Images were taken at 60 × magnification. (B) CD38⁺ B cells and L-CD31⁺ transfectants were interacted for 5 minutes, before lysis with Brij98 and membrane separation by ultracentrifugation. CD19 molecules were highlighted by Western blotting, while CD45 was detected by means of a dot blot using the same lysates. (C) Nalm-6 B cells were treated with anti-CD38 antibody (10 minutes, on ice) followed by a DαMIgG (10 minutes, on ice) and incubated at 37°C for 5 minutes. Lysates were then immunoprecipitated using the anti-CD38 OKT10 antibody, or an irrelevant isotype-matched antibody. CD19 molecules were visualized by Western blotting.