GC formation in Polζ f/Δ /CD21-cre mice. (A) Generation of GC B cells. Mice were immunized with 100 µg NP-CG in alum and analyzed for the presence of CD19 + PNA + Fas + GC B cells 14 d after immunization. Only CD19 + cells are shown. SPL, spleen; PP, Peyer's patches; MLN, mesenteric lymph nodes. Data represent one of two independent experiments. (B) Deletion efficiency of the Polζ f allele. The Polζ f and Polζ Δ alleles in B cells of Polζ f/Δ /CD21-cre and control mice were amplified in a competitive PCR using primers that anneal 5′, within, and 3′ of the floxed region and compared with a standard with known ratios of the two alleles. The fragments corresponding to the floxed and deleted allele migrate at around 300 and 450 bp, respectively.
{}