Figure 4. Effect of TCDD on the CD40L-induced mRNA expression of plasmacytic differentiation regulators in mouse B cells.

Freshly isolated mouse B cells (1 × 10⁶/ml) were treated with TCDD at concentrations indicated or vehicle (VH), and then co-cultured with irradiated CD40L-L cells (5 × 10⁴ cell/well) in the presence of recombinant mouse IL-2 (10 U/ml), IL-6 (100 U/ml), and IL-10 (20 ng/ml) for 3 days. Cells were transferred to new plates in the absence of CD40L-L cells on Day 3, and cultured for two additional days. Cells were harvested on Day 1 and Day 5, total RNA was isolated using RNeasy Kit, and steady state mRNA levels of (A) Blimp-1 and (B) Pax5 were measured by Taqman real-time PCR and normalized to endogenous 18S ribosomal RNA. Data are presented as fold change compared to the CD40L group on Day 1. *, p < 0.05, **, p < 0.01, compared to the VH-treated group on Day 5. Three experimental replicates were included in each group. Data are representative of two separate experiments in which mRNA levels of Blimp-1 and Pax5 were modulated by TCDD.