Enhancement of human B-cell proliferation by a monoclonal antibody to CD43.
Monoclonal antibodies (MoAb) to human leucocyte sialoglycoprotein, CD43, have been shown to deliver mitogenic signals to human T cells or to enhance T-cell proliferation induced by concanavalin A, anti-CD3 antibodies or phorbol ester. In this paper, we studied the effects of anti-CD43 MoAb B1B6 on the activation of human B cells. Anti-CD43 MoAb B1B6 was not mitogenic by itself for human B cells. However, when added together with TPA, both resting and in vivo activated tonsillar B cells, containing 5-10% and about 35% CD43+ respectively, responded with three- to fivefold higher proliferation compared to that obtained with TPA alone. A peak in the proliferative response was reached on day 3. Optimal proliferation was obtained when the antibody was present from the start of culturing. Addition of MoAb B1B6 together with a calcium ionophore, ionomycin, did not induce B-cell proliferation. Neither did mAb B1B6 sustain the growth of B cells that were already in the cell cycle, i.e. precultured with phorbol ester (PDB) and ionomycin for 3 days. The results are similar to those obtained with antibodies to CD22 and CD23 and show that early progression signals are delivered to resting B cells through CD43 in the presence of primary activators of protein kinase C.
Wikén
M
M
University of Stockholm, Department of Immunology, Sweden.
Björck
P
P
Axelsson
B
B
Perlmann
P
P
D000276:Adjuvants, Immunologic / Q000502:physiology*; D000911:Antibodies, Monoclonal / Q000502:physiology*; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000502:physiology; D004987:Ethers; D006801:Humans; D007399:Interphase / Q000187:drug effects; D015759:Ionomycin; D007476:Ionophores; D007700:Kinetics; D051917:Leukosialin; D008213:Lymphocyte Activation / Q000187:drug effects; D010703:Phorbol Esters; D012795:Sialoglycoproteins
D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D004987:Ethers; D007476:Ionophores; D051917:Leukosialin; D010703:Phorbol Esters; C465014:SPN protein, human; D012795:Sialoglycoproteins; D015759:Ionomycin