title: Production of multiple lymphokines by the A20.1 B cell lymphoma after cross-linking of membrane Ig by immobilized anti-Ig.
abstract: Cross-linking of membrane IgG2a or IgD on the B cell lymphoma A20.1 resulted in the elaboration of lymphokines which were able to support the growth of HT-2 cells and to induce increased Ia expression on resting B cells. Unstimulated A20.1 cell did not produce detectable levels of lymphokine activity. Lymphokine secretion did not occur in response to cross-linking of MHC class II (Ia) or class I (H2K) molecules. The kinetics for secretion were rapid, with detectable levels of lymphokine arising within 3 to 4 h of stimulation. Maximal lymphokine production was reached by 8 to 10 h. Soluble intact anti-Ig antibodies failed to stimulate lymphokine production due to Fc-mediated effects. This was concluded based on the fact that soluble F(ab')2 fragments of anti-IgG, but not soluble intact antibody, stimulated the production of lymphokine by A20.1 cells. Based on serologic criteria, membrane Ig cross-linking by ligand induced secretion of IL-2 but not IL-4 by A20.1 cells. Induction of Ia expression by resting B cells in response to A20.1 supernatant was not mimicked by stimulation with IL-1, -3, -5, or -6 either singly or in combination. Furthermore, preliminary physicochemical characterization revealed that the Ia-inducing factor in A20.1 supernatant has a molecular weight greater than 50,000. These data suggest that the Ia-inducing activity is a novel lymphokine. Thus, this report describes the first evidence for the existence of a B cell tropic lymphokine produced by B cells in response to Ag receptor-mediated signal transduction.
authors.affiliation: Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
authors.forename: L B
authors.initials: LB
authors.lastname: Justement
authors.forename: J
authors.initials: J
authors.lastname: Kreiger
authors.forename: J C
authors.initials: JC
authors.lastname: Cambier
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D001402:B-Lymphocytes / Q000145:classification / Q000378:metabolism* / Q000502:physiology; D002460:Cell Line; D002474:Cell-Free System; D003432:Cross-Linking Reagents; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D007378:Interleukins / Q000502:physiology; D007399:Interphase; D007700:Kinetics; D008222:Lymphokines / Q000096:biosynthesis* / Q000302:isolation & purification / Q000502:physiology; D008223:Lymphoma / Q000276:immunology / Q000378:metabolism*; D016215:Macrophage-Activating Factors; D051379:Mice; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000302:isolation & purification; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism
chemical_list: D000888:Antibodies, Anti-Idiotypic; D003432:Cross-Linking Reagents; D000949:Histocompatibility Antigens Class II; D007378:Interleukins; D008222:Lymphokines; D016215:Macrophage-Activating Factors; D009363:Neoplasm Proteins; D011947:Receptors, Antigen, B-Cell; D011971:Receptors, Immunologic