Western blotting of various primary samples and cell lines. (A) The B28p mAb recognizes a 28-kDa protein expressed in B cells and plasma cells. B28p identifies a band of approximately 28 kDa (arrow) in a Western blot of lysates from the NHL-FCC patient sample (lane 2), peripheral blood (PB) purified B cells (lane 3), 2 multiple myeloma (MM) patients (lanes 5 and 6), the Thiel myeloma cell line (lane 7), and the HeLa cell line (lane 8). The 28-kDa band was undetectable in the U937 cell line (lane 1) and barely detectable in normal T cells purified from peripheral blood (lane 4). Similar amounts of total protein lysates were loaded in each lane (see antiactin Western blot, bottom). None of the samples showed IRTA1 expression at immunohistochemical and Western blot analyses using the M-IRTA1 mAb (not shown). (B-C) B28p mAb and an anti-TPD52 polyclonal antibody recognize the same band of about 28 kDa in TPD52-transfected Phoenix cells. A band (arrow) of the expected molecular weight of TPD52 (about 28 kDa) is selectively detected by the B28 mAb (A) in cells transfected with human TPD52 (hTPD52) but not in cells transfected with murine TPD52 (mTPD52) or with the empty vector. A rabbit polyclonal antibody (here abbreviated as TPD52 pAb), known to recognize both hTPD52 and mTPD52, detects (C) the same band of about 28 kDa (arrow) in cells transfected with hTPD52 or with mTPD52 but not in cells transfected with the empty vector. An antiactin Western blot is shown as loading control in the bottom part of the 2 panels.