The B29 and mb-1 polypeptides are differentially expressed during human B cell differentiation.
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.
Mason
D Y
DY
Department of Haematology, John Radcliffe Hospital, Headington, Oxford, GB.
van Noesel
C J
CJ
Cordell
J L
JL
Comans-Bitter
W M
WM
Micklem
K
K
Tse
A G
AG
van Lier
R A
RA
van Dongen
J J
JJ
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*
D015703:Antigens, CD; D051925:CD79 Antigens; C497881:CD79A protein, human; C497883:CD79B protein, human; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D011947:Receptors, Antigen, B-Cell