Eμ-TCL1 CLL cells express XBP-1, IRF4, Blimp-1, and AID at higher levels. (A) CD5⁻/B220⁺ B cells purified from 6-week-old wild-type and Eμ-TCL1 mice were stimulated with LPS for a course of 3 days, and lysed for analysis by immunoblots for indicated proteins. Data shown in each immunoblot are representative of 3 independent experiments. For each experiment, CD5⁻/B220⁺ wild-type and Eμ-TCL1 B cells were purified and pooled from at least 2 mouse spleens. (B) CD5⁻/B220⁺ B cells purified from 8-month-old wild-type mice and CD5⁺/B220⁺ CLL cells from 8-month-old Eμ-TCL1 mice were stimulated by LPS for 3 days and lysed for analysis by immunoblots for indicated proteins. Data shown in each immunoblot are representative of 3 independent experiments. For each experiment, CD5⁻/B220⁺ wild-type B cells and CD5⁺/B220⁺ CLL cells were purified and pooled from at least 2 mouse spleens.