Figure 5. In vitro and in vivo generated Lgals1^−/− plasmablasts are more susceptible to apoptosis than WT plasmablasts.

(A-C) B220⁺ splenic B cells from WT and Lgals1^−/− mice were cultured with 1μg/ml LPS during 3 days in complete medium containing 10% or 5% FCS. (A) Quantification of apoptotic B220^lowCD138⁺ plasmablasts was determined by 7-AAD incorporation. (B) Quantification of mitochondrial depolarization and phosphatidyl serine externalization on B220^lowCD138⁺ plasmablasts using mitotracker and annexin V staining. Lived cells are mitotracker^high/annexinV⁻, cells with externalized phosphatidyl serines are mitotracker^high/annexinV⁺ and cells with a decreased mitochondirial potential are mitotracker^low/annexinV⁺. (C) Quantification of caspase 8 activation. Fold changes in active caspase 8 MFI in B220^lowCD138⁺ plasmablasts generated in culture medium supplemented with 10% or 5% FCS are represented. Data in A and B are representative of 3 independent experiments. (D) WT and Lgals1^−/− mice were immunized with NP-KLH in alum (T-dependent Ag), 6 mice for each group, and the percentage of splenic apoptotic cells within IgM⁺CD138⁺ cells was quantified using TUNEL assays at day 21. For WT and Lgas1^−/− mice 3893 and 2154 cells were counted, respectively.

* and ** indicate significance versus WT mice with p<0.05 and <0.005 respectively.