CDw40 and BLCa‐specific monoclonal antibodies detect two distinct molecules which transmit progression signals to human B lymphocytes

Abstract

Two monoclonal antibodies (mAb), MA6 and G28-5, have the common property of detecting markers expressed on both B lymphocytes and carcinomas: BLCa (B lymphocyte carcinoma cross-reacting antigen) and CDw40 (Bp50). A comparison of the reactivity of these mAb revealed that MA6 and G28-5 detect distinct epitopes with different cell line and tissue distributions. L cell transfectants expressing CDw40 were not bound by MA6 anti-BLCa, but were bound by G28-5 anti-CDw40. G28-5 or a CDw40-specific heterantiserum could not block the migration of BLCa, while MA6 antibody could. These results indicate that CDw40 and BLCa are distinct surface molecules. Both G28-5 anti-CDw40 and MA6 anti-BLCa mAb could provide progression signals for B cells activated by appropriate B cell activators such as phorbol esters or anti-immunoglobulin; however, only G28-5 anti-CDw40 and not MA6 was co-stimulatory with the anti-CD20 competence signal, demonstrating a clear difference in the CDw40 and BLCa-mediated progression signals. Apparently, these molecules, although structurally distinct, have related functions in B cell activation.

Vav‐1 expression correlates with NFκB activation and CD40‐mediated cell death in diffuse large B‐cell lymphoma cell lines

“…A hybridoma line producing anti-human CD40 (G28.5) [26] was provided by Dr. Bruce Mazer, McGill University, Montreal, PQ, Canada. Ramos and Raji cells are available from the ATCC (Manassas, VA, USA).…”

Human Immunodeficiency Virus Type 1-Associated CD40 Ligand Transactivates B Lymphocytes and Promotes Infection of CD4+T Cells

“…The vector coding for human CD40L (i.e., pcDNA3.1-CD40L) was provided by R. Kornbluth (University of California San Diego) (36). The anti-CD40 hybridoma G28.5 (IgG1) (15) and the anti-CD40L hybridoma 5c8 (IgG2a) (39) were generously provided by W. Mourad (Université de Montréal). The antibody against the NF-B p50 subunit was purchased from Santa Cruz, while the antibody specific for the anti-NF-B p65 subunit was kindly given by N. Rice (National Cancer Institute-Frederick Cancer Research and Development Center) (60).…”

Constitutive Activation of Extracellular Signal-Regulated Kinase Predisposes Diffuse Large B-Cell Lymphoma Cell Lines to CD40-Mediated Cell Death

“…A hybridoma line producing anti-human CD40 (clone G28.5; ref. 15) was provided by Dr. Bruce Mazer (McGill University, Montreal, Quebec, Canada). The cell lines were maintained in RPMI 1640 (Sigma, Oakville, Ontario, Canada) supplemented with 10% bovine growth serum (VWR Canlab, Montreal, Quebec, Canada), 0.2 mmol/L glutamine, 0.05 mmol/L h-mercaptoethanol, 100 units/mL penicillin, and 100 Ag/mL streptomycin in a 5% CO 2 atmosphere at 37jC.…”