Characterization of soluble factors that induce the cytolytic activity and the expression of T cell growth factor receptors of a T cell hybrid.
A rat X mouse T cell hybrid (PC60) proliferates in the absence of T cell growth factor (TCGF) and its cytolytic activity can be induced by culture in mixed leukocyte culture supernatants or concanavalin A-activated rat spleen cell supernatant (CS) to lyse 51Cr-labeled tumor target cells. To characterize the factor(s) responsible for this reversible induction, serum-free CS was fractionated by reverse phase high performance liquid chromatography and by phenyl-Sepharose chromatography. A cytotoxicity-inducing activity (CIA) was separated from TCGF and macrophage-activating factor/interferon-gamma. CIA was found to be a macromolecule with an apparent molecular weight of 12,000-18,000 and a pI of 5.0 and 6.2. Its activity on PC60 cells depended on the addition of TCGF. Thus TCGF may have other effects on T cells than the induction of entry into cell cycle. The number of TCGF surface receptors on PC60 cells was measured using purified 3H-TCGF. TCGF receptors were undetectable on noninduced cells but appeared during induction. The expression of TCGF receptors was not induced either by TCGF or by CIA-containing supernatants or fractions alone, only by a combination of both. These results show that TCGF plays a role in the regulation of the expression of its own receptors.
D000818:Animals; D002460:Cell Line; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D003602:Cytotoxicity, Immunologic; D006801:Humans; D006825:Hybridomas / Q000276:immunology* / Q000378:metabolism; D007371:Interferon-gamma / Q000302:isolation & purification; D007376:Interleukin-2 / Q000302:isolation & purification / Q000502:physiology*; D007525:Isoelectric Focusing; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008970:Molecular Weight; D051381:Rats; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D015375:Receptors, Interleukin-2; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism
D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D007371:Interferon-gamma