Expression of CD9 antigen on normal activated human B cells.
The expression of the CD9 pre-B acute lymphoblastic leukemia (ALL)-associated antigen was studied. CD9-positive B cells were enriched in the in vivo-activated buoyant B cell population isolated from tonsils. Small tonsil B cells activated in vitro with either PWM, phorbol 12-myristate 13-acetate (TPA), or anti-Ig plus low Mr B cell growth factor (BCGF) also demonstrated increased CD9 expression. The peak of CD9 expression (30-40% positive cells) occurred after 4-6 days of activation. The kinetics of increased CD9 expression was similar to that of the 4F2 activation antigen. CD9 antigen expression on tonsillar B cells as well as on pre-B leukemic cell lines was associated with protein kinase C activation. Two phorbols that activate protein kinase C (TPA; phorbol 12,13-dibutyrate) induced expression of the CD9 antigen whereas a phorbol analogue that does not activate C kinase (4-alpha-phorbol 12,13-didecanoate) and an analogue that is a very weak agonist (phorbol 12-myristate 13-acetate-4-0-methyl ether) were unable to induce CD9 expression on tonsil B cells or on the cell lines. The effect of the anti-CD9 monoclonal antibody, DU-ALL-1, on B cell mitogenesis was studied. Dense or buoyant tonsillar B cells were cultured in the presence or absence of DU-ALL-1 antibody plus PWM, anti-Ig, and BCGF, DU-ALL-1 antibody did not inhibit or augment the mitogenic response of resting or activated B cells. These results indicate that the CD9 pre-B ALL antigen is present on a population of normal activated tonsillar B cells and that its induction of expression is associated with protein kinase C activation.
Zeleznik-Le
N J
NJ
Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710.
Metzgar
R S
RS
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000032:analysis*; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology*; D002460:Cell Line; D002469:Cell Separation; D004789:Enzyme Activation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008562:Membrane Glycoproteins; D014066:Palatine Tonsil; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D060245:Tetraspanin 29
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D011043:Pokeweed Mitogens; D060245:Tetraspanin 29; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate