FIG. 4.

BOB.1/OBF.1 is expressed in MZ B cells. Wild-type splenic B cells were sorted on the basis of the expression of CD21 and CD23 to follicular (FO) (CD21^med CD23^high) and MZ (CD21^high CD23^low/neg) B cells. (A) Total RNA was isolated, and RT-PCR with primers specific for BOB.1/OBF.1 and β-actin was performed. (B) Western blot analysis of whole-cell extracts was performed with antibodies specific for the BOB.1/OBF.1 and RelA proteins. As a positive control, a whole-cell extract of PD31 cells was used. (C) Wild-type spleen sections were stained with anti-BOB.1/OBF.1 antibody (brown), counterstained with hematoxylin, and viewed at original magnifications of ×100 and ×200. B- and T-cell zones (B and T, respectively) and red pulp (RP) are indicated.