title: Partial purification and characterization of immunoglobulin production stimulating factor derived from Namalwa cells.
abstract: We screened for immunoglobulin (Ig) production stimulating factor (IPSF) which enhanced Ig production of human-to-human hybridomas in serum-free culture, and found that culture supernatant and lysate of human lymphoblastoid Namalwa cells stimulated proliferation and Ig production of human-to-human hybridoma HB4C5 cells. The IPSF in Namalwa lysate was partially purified with DEAE-Toyopearl 650M, hydroxylapatite and Superose 6HR 10/30 column chromatographies. The partially purified IPSF was a macromolecule of about 500,000 dalton containing 72,000 dalton protein as a major component. The activity was stable at pH 6 to 12, but inactivated partially by heating over 40 degrees C (60% decrease) and completely by trypsin digestion. These results suggest that the IPSF activity is due to its protein and heat-stable components. The Namalwa IPSF stimulated proliferation of human-to-human hybridomas but not that of mouse-to-mouse hybridomas. The IPSF also stimulated Ig production of human-to-human hybridomas derived from NAT-30 cells, but not that of other human-to-human or mouse-to-mouse hybridomas. NAT-30 is a human fusion partner derived from Namalwa cells. These results suggest that the Namalwa IPSF is an autocrine factor that stimulates proliferation and Ig production of hybridomas derived from NAT-30 cells.
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Akiyoshi
authors.forename: H
authors.initials: H
authors.lastname: Murakami
authors.forename: T
authors.initials: T
authors.lastname: Sugahara
authors.forename: I
authors.initials: I
authors.lastname: Ikeda
authors.forename: K
authors.initials: K
authors.lastname: Toyoda
authors.forename: H
authors.initials: H
authors.lastname: Omura
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D002051:Burkitt Lymphoma / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D002845:Chromatography; D006133:Growth Substances / Q000302:isolation & purification* / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D006825:Hybridomas / Q000276:immunology*; D007075:Immunoglobulin M / Q000096:biosynthesis*; D051379:Mice; D008970:Molecular Weight; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D006133:Growth Substances; D007075:Immunoglobulin M; D014357:Trypsin