title: Identification of a T cell hybridoma that produces large quantities of macrophage-activating factor.
abstract: A murine T cell hybridoma, constructed by fusion of alloantigen-activated T cells with the BW5147 T cell lymphoma, which produces a lymphokine capable of inducing tumoricidal activity in macrophages, has been identified. Lymphokine release could be detected only after mitogen stimulation of the T cell hybridoma culture. Upon cloning of the parental hybridoma, 24 out of 27 clones produced tumoricidal-inducing activity. Seven clones produced more cytocidal-inducing activity than did conventional supernatants, generated by concanavalin A stimulation of normal murine spleen cell cultures, which contained macrophage-activating factor (MAF). The supernatant of hybridoma clone 24/G1 was 25 times more active than conventional MAF preparations. Using supernatants from a variety of clones, the levels of macrophage-activating activity and interleukin 2 were found to vary independently of one another. The lymphokine produced by hybridoma clone 24/G1 appeared to be identical to conventional MAF by a variety of criteria including: (a) a requirement for a second signal for induction of tumoricidal activity in macrophages, (b) inactivation after incubation for 1 h at 65 degrees C, and (c) loss of activity after treatment at pH 4.0 but not at pH 5.0. Like conventional MAF, the hybridoma MAF eluted as a single peak after molecular sieve chromatography on Sephadex G100 and exhibited an apparent molecular weight of 55,000. Although somewhat heterogeneous, the majority of hybridoma 24/G1 MAF displayed an isoelectric point of 5.4 as determined using the chromatofocusing technique. These results thus illustrate the usefulness of T cell hybridomas in distinguishing between various lymphokine activities and indicate that the T cell hybridoma clone 24/G1 will be of particular usefulness in achieving the biochemical purification of substantial quantities of murine MAF.
mesh_terms: D000818:Animals; D006358:Hot Temperature; D006825:Hybridomas / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007376:Interleukin-2 / Q000096:biosynthesis; D007526:Isoelectric Point; D008222:Lymphokines / Q000096:biosynthesis* / Q000494:pharmacology; D016215:Macrophage-Activating Factors; D051379:Mice; D008970:Molecular Weight; D013601:T-Lymphocytes
chemical_list: D007376:Interleukin-2; D008222:Lymphokines; D016215:Macrophage-Activating Factors