CM1 ligation initiates apoptosis in a caspase 8-dependent manner in Ramos cells and in a mitochondria-controlled manner in Raji cells

Ligation of Centrocyte/Centroblast Marker 1 on Epstein-Barr Virus–Transformed B Lymphocytes Induces Cell Death in a Reactive Oxygen Species–Dependent Manner

“…In a recent study, it was reported that the ligation of CM1 on Burkitt lymphoma cell lines induces apoptosis via the mitochondria or in a caspase-controlled manner [8]. In the present study, the ligation of CM1 on EBVtransformed B cells also induced apoptosis (Figs.…”

“…Interestingly, it has been reported that CM1 induces mitochondria-controlled apoptosis in Raji and EBVpositive Burkitt's lymphoma, and that Z-VAD-fmk inhibits CM1-mediated Raji apoptosis under the same conditions as those used in the present study [8]. This discrepancy between Raji and freshly EBV-transformed B cells would be explained by undetermined alterations during the establishment of permanent cell lines.…”

“…It has been reported that several B-lymphoma cell lines, including Raji, Ramos, and IM-9, express surface CM1 molecules [7]. In primary germinal center B cells purified from the human tonsil, the ligation of CM1 induces cell death in Raji, Ramos, and IM9 [7,8]. However, the precise apoptotic mechanisms triggered by CM1-ligation are unclear, so we undertook the present study to determine how CM1-ligation induces the apoptosis of germinal center cells.…”

“…To determine whether CM1 could induce the apoptosis of CM1-expressing cells, as described in one of our previous studies [7,8], EBV-transformed B cells were stimulated with anti-CM1 antibody for 30 minutes, and 1, 2, and 6 hours. Cells were stained with FITClabeled annexin-V and analyzed by flow cytometry.…”

“…Several cell lines, such as Raji, Ramos, and IM-9, which originate from human B cells, express surface CM1 molecules [7]. CM1 is specifically expressed on germinal center B cells when these cells are ligated with anti-CM1 monoclonal antibody, and the cells may undergo apoptosis [7,8]. However, the apoptotic mechanisms triggered by CM1-ligation are unknown.…”