title: Direct binding of IL-12 to human and murine B lymphocytes.
abstract: IL-12 has been shown to play a central role in cell-mediated inflammatory reactions through direct activation of T cells and NK cells. IL-12 also strongly influences humoral immunity but these effects have been thought to be indirect and caused by intermediary cytokines. Using flow cytometry, we now show that IL-12 directly interacts with B cells. Freshly isolated murine peritoneal B-1 and conventional B lymphocytes bound IL-12, but splenic B cells failed to react unless first stimulated with lipopolysaccharide. All murine B cell sources were found to express IL-12R beta 1 subunit transcripts as detected by PCR and RNase protection assays. IL-12 binding was also detected on phytohemagglutinin-stimulated human T cell blasts and Staphylococcus aureusl IL-2-stimulated B cell blasts but not on freshly isolated peripheral blood lymphocytes. Similarly, IL-12 directly bound to the human SKW6.4 Burkitt's B cell lymphoma line. In all cases positive staining was ablated by omitting IL-12 from the procedure, showing that it was not due to detection of endogenous IL-12. These findings indicate that B cells represent another major target for IL-12 in addition to T and NK cells, and that IL-12 can directly affect humoral immunity.
authors.affiliation: Department of Microbiology and immunology, Medical College of Ohio, Toledo 43699-0008, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Vogel
authors.forename: L C
authors.initials: LC
authors.lastname: Showe
authors.forename: T L
authors.initials: TL
authors.lastname: Lester
authors.forename: R M
authors.initials: RM
authors.lastname: McNutt
authors.forename: V H
authors.initials: VH
authors.lastname: Van Cleave
authors.forename: D W
authors.initials: DW
authors.lastname: Metzger
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002051:Burkitt Lymphoma; D005434:Flow Cytometry; D006801:Humans; D018664:Interleukin-12 / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011485:Protein Binding / Q000276:immunology; D018123:Receptors, Interleukin / Q000032:analysis; D053707:Receptors, Interleukin-12; D014407:Tumor Cells, Cultured
chemical_list: D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D018664:Interleukin-12