Studies on the role of CD43 in human B-cell activation and differentiation.
The monoclonal antibody (MoAb) B1B6 to human leucocyte sialoglycoprotein, CD43, induces aggregation of T cells and delivers progression signals early during activation of both T and B cells in the presence of primary activators of protein kinase C. In this report we further studied the role of CD43 in human B-cell activation and differentiation. About 5-10% of resting tonsillar B cells are CD43+. In the presence of TPA or antibodies to CDw40, the proportions of CD43+ cells drastically increased. The expression was optimal on day 3 of culture, when up to 80% and 50%, respectively, were CD43+. Whereas MoAb B1B6 together with TPA induced a three- to fivefold higher proliferative response as compared to TPA alone, antibodies to CDw40 did not synergize with MoAb B1B6 in B-cell proliferation. Tonsillar populations depleted of CD43+ B cells responded with lower proliferation to TPA alone or to TPA and B1B6 or anti-CDw40 antibodies. MoAb B1B6 did not affect the production of IgM or IgG as induced by pokeweed mitogen in the presence of autologous T cells, from either peripheral blood or tonsillar B cells. Neither did it affect the IgG production from the CD43+ BSF-2 sensitive Epstein-Barr virus-transformed lymphoblastoid cell line CESS. The results show that CD43 is upregulated on B cells during activation. Furthermore, CD43+ B cells are included in the population which responds to signals delivered by TPA, anti-CD43 or anti-CDw40 antibodies, and the proliferation of this population is not merely due to an expansion of the small population of CD43+ cells present among these cells. Moreover, the epitopes recognized by MoAb B1B6 are not involved in the differentiation of and ultimate Ig-secretion from activated B cells.
Wikén
M
M
University of Stockholm, Department of Immunology, Sweden.
Björck
P
P
Axelsson
B
B
Perlmann
P
P
D000911:Antibodies, Monoclonal / Q000502:physiology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology*; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D004357:Drug Synergism; D006801:Humans; D007106:Immune Sera; D007074:Immunoglobulin G / Q000096:biosynthesis; D051917:Leukosialin; D008213:Lymphocyte Activation / Q000187:drug effects; D010641:Phenotype; D011043:Pokeweed Mitogens; D012795:Sialoglycoproteins; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D007106:Immune Sera; D007074:Immunoglobulin G; D051917:Leukosialin; D011043:Pokeweed Mitogens; C465014:SPN protein, human; D012795:Sialoglycoproteins; D013755:Tetradecanoylphorbol Acetate