Enhancement of Human B‐Cell Proliferation by a Monoclonal Antibody to CD43

Abstract

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.

CD43 and CD5 antibodies define four normal and neoplastic B‐cell subsets: A three‐color flow cytometric study

“…Cell suspension studies have identified CD43 on virtually all T cells, on -25-30% ofperipheral and umbilical cord blood B cells and on 10-15% of tonsillar B cells ( 3 , 2 3 ) . CD43 expression has been associated with activation and differentiation of B cells as well as being found more frequently on B cells synthesizing IgG rather than IgM (22)(23)(24)(25). CD43 has also been associated with T-cell and monocyte activation (10,12).…”

“…(1,3,4,13). Functionally, it is associated with lymphocyte activation and differentiation and possibly maintenance of cellular "integrity" (3,12,(21)(22)(23)(24)(25).…”

CD164 Monoclonal Antibodies That Block Hemopoietic Progenitor Cell Adhesion and Proliferation Interact with the First Mucin Domain of the CD164 Receptor

“…6 -10). Like CD164, the PSGL-1, CD34, and CD43 sialomucins may also function as signaling molecules that regulate cell proliferation (11)(12)(13)(14)(15)(16)(17)(18), possibly by enabling other receptor-ligand interactions to occur. These diverse functions are thought to be the result, at least in part, of cell type-and stage-specific oligosaccharide modifications, particularly those involving sialylation (19 -22; reviewed in Refs.…”

hnRNP-K and Purα act together to repress the transcriptional activity of the CD43 gene promoter

“…[29][30][31][32] In addition, antibodies to CD43 have been shown to activate monocytes, B lymphocytes, and dendritic, mast, and natural killer cells. [33][34][35][36][37][38][39] CD43 binds major histocompatibility complex (MHC) class I molecules and activates T lymphocytes in a manner independent of both the T lymphocyte receptor/CD3 complex and CD28. [40][41][42][43] The activation signals of this pathway are mediated through phosphorylation of the intracellular domain of CD43 and its physical interaction with the tyrosine kinases Fyn and Lck and the serine/threonine kinase STANK.…”