Fig. 5. Co-activator binding is enhanced in CD40-activated B cells.

Chromatin was prepared from resting IgM+/IgG- peripheral B cells that was either unstimulated (upper panel) or stimulated for 2 h with 0.5 μg/ml sCD40L. Immunoprecipitation was carried out with antibodies specific for p50, CREB and p300. Eluted DNA was amplified with Iγ1-specific primers (left panels) or control IgHG1 primers (left panels). 10-fold serial dilutions of the chromatin (starting with a 1:10 dilution of the immunoprecipitated product) were used to demonstrate linearity of the PCR reaction. Products were quantified by determining the fold increase signal over the “no antibody” signal (used with permission, The Journal of Immunology 2005; 175:4499-4507).