title: Generation of heterohybridomas secreting human immunoglobulins; pokeweed mitogen prestimulation is highly effective but phytohemagglutinin drives most B cells into apoptosis.
abstract: Human monoclonal antibodies have commonly been generated by forming hybridomas of stable lymphoblastoid cell lines and Epstein-Barr virus (EBV)-transformed human B cells that have been exposed to phytohaemagglutin (PHA)-stimulated T cells. However, this technique has predominantly given rise to IgM- but very rarely IgG- or IgA-producing clones. We now report that, regardless of prior EBV infection, pokeweed mitogen (PWM) stimulation of human peripheral blood mononuclear cells (PBMCs) generated much higher numbers of IgM-, IgA- and IgG-producing B cells than did stimulation with PHA. Fusion of PWM-stimulated PBMCs with a mouse myeloma cell line also gave rise to 7- to 12-fold higher numbers of IgG- and IgA-producing heterohybridomas than PBMCs that were prestimulated with PHA. Judged by Annexin V staining, stimulation with PHA induced a very high rate of B cell apoptosis within 24 h, whereas, even after 7 days, PWM stimulation only induced marginal B cell apoptosis. This should explain why PHA is much inferior to PWM in stimulating immunoglobulin (Ig) production in vitro and in generating immunoglobulin-producing human B cell hybridomas. It is concluded that PWM stimulation may greatly facilitate the generation of human monoclonal antibodies of all isotypes.
authors.affiliation: Department of Immunology, National University Hospital, 101 Reykjavík, Iceland.
authors.forename: Sturla
authors.initials: S
authors.lastname: Arinbjarnarson
authors.forename: Helgi
authors.initials: H
authors.lastname: Valdimarsson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D002461:Cell Line, Transformed; D006801:Humans; D006825:Hybridomas / Q000276:immunology*; D007132:Immunoglobulin Isotypes / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D010835:Phytohemagglutinins / Q000276:immunology; D011043:Pokeweed Mitogens / Q000276:immunology
chemical_list: D007132:Immunoglobulin Isotypes; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens