title: The B29 and mb-1 polypeptides are differentially expressed during human B cell differentiation.
abstract: Surface immunoglobulin on mouse B cells is associated with a heterodimer comprising the products of the mb-1 and B29 genes. Here we report that antibodies raised against a peptide sequence from the intracytoplasmic C terminus of the B29 murine gene product detect the 37-kDa component of the human heterodimer, indicating that this component in man is also encoded by the B29 gene. The immunocytochemical reactivity of these anti-B29 antibodies was compared with those of antibodies to the mb-1 protein. Of 25 cases of acute lymphoblastic leukaemia (ALL), 24 were positive for mb-1 whereas B29 was expressed in only 13 cases. Most of these B29-positive ALL expressed immunoglobulin mu heavy chain in their cytoplasm (pre-B ALL). In lymphoid tissue sections, anti-B29-labeled B cell follicles in a similar fashion to anti-mb-1, with the striking exception that plasma cells were unreactive for B29, but positive for mb-1. These results suggest that the synthesis of B29 begins later in precursor B cells than that of mb-1, and ceases before the terminal plasmacyte phase.
authors.affiliation: Department of Haematology, John Radcliffe Hospital, Headington, Oxford, GB.
authors.forename: D Y
authors.initials: DY
authors.lastname: Mason
authors.forename: C J
authors.initials: CJ
authors.lastname: van Noesel
authors.forename: J L
authors.initials: JL
authors.lastname: Cordell
authors.forename: W M
authors.initials: WM
authors.lastname: Comans-Bitter
authors.forename: K
authors.initials: K
authors.lastname: Micklem
authors.forename: A G
authors.initials: AG
authors.lastname: Tse
authors.forename: R A
authors.initials: RA
authors.lastname: van Lier
authors.forename: J J
authors.initials: JJ
authors.lastname: van Dongen
mesh_terms: D000818:Animals; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology*; D051925:CD79 Antigens; D002454:Cell Differentiation; D006801:Humans; D008562:Membrane Glycoproteins / Q000032:analysis*; D010750:Phosphoproteins / Q000032:analysis*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology; D011817:Rabbits; D011947:Receptors, Antigen, B-Cell / Q000032:analysis*
chemical_list: D015703:Antigens, CD; D051925:CD79 Antigens; C497881:CD79A protein, human; C497883:CD79B protein, human; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D011947:Receptors, Antigen, B-Cell