Splenic B cells lacking the Cebpa +37 kb enhancer
retain normal immunoglobulin heavy chain class switching. (A)
Genomic DNA from CD43- splenic B cells from two Enh(f/f) and two
Enh(f/f);Mx1-Cre mice exposed 4 wks earlier to pIpC were analyzed for retention
of the floxed Cebpa enhancer by PCR. (B)
Representative FC data for transitional and mature splenic B cells from
Cebpa Enh(f/f) and Cebpa Enh(f/f);Mx1-Cre
mice (left), and enumeration of these subsets (right, mean and SD from four
determinations). (C) Enumeration of transitional and mature splenic
B cells for Enh(f/f) and Enh(f/f);Mb1-Cre mice (mean and SD from three
determinations). (D) Representative FC for IgE, IgG1, and IgG2b
expression in splenic B cells cultured with IL-4 and either anti-CD40 antibody
or LPS for 4 days, with mean values with SD for the percentage of Ig-expressing
cells from two determinations shown. (E) Serum from Enh(f/f) and
Enh(f/f);Mx1-Cre mice was evaluated for IgM, IgG, and IgA by ELISA (mean and SD
from three determinations).