Membrane alteration responsible for the induction of gamma interferon

Abstract

Induction of gamma interferon in human lymphoid cells cultures appears to be dependent upon specific membrane-mediated events and calcium flux. Since blastic response had been observed after enzymic oxidation of membrane-bound galactose residues, we used this system to study the nature of membrane alterations responsible for the activation of interferon induction. The results of these experiments suggest that a membrane oxidation is essential for interferon induction and depletion of calcium abolishes interferon production. In addition, we have shown that interferon induction by concanavalin A, phytohemagglutinin, and staphylococcal enterotoxin A, but not by galactose oxidase is prevented by cleavage of N-acetylneuraminic acid residues. Thus, interferon induction in human lymphoid cell cultures by galactose oxidase, concanavalin A, phytohemagglutinin, staphylococcal enterotoxin A, and NaIO4 appears to reside in terminal oligosaccharides of the cell membrane. How this specific membrane event relates to the derepression of the interferon locus is being actively pursued.

Impaired Gamma Interferon Production by Cells from Patients with Lymphoproliferative Disorders of Mature T and NK Cells

“…Thus, our data indicate an intrinsic defect in IFN-y production by the abnormally expanded T or NK cells in patients with T-CLL or GL expansions. IFN-y production is thought to be the result of two separate induction steps: (1) oxidation of galactose residues at the cell membrane level, followed by (2) activation of calcium flow through the membrane, which may act as a 'second messenger' in triggering IFN production [3]. Indeed, considerable IFN-y production was obtained in these tested patients by treating the cells with calcium ionophore A23187, thus showing that the defect lies in the first step, at the cell membrane level.…”

“…La Jolla, Calif., USA) at a concentration of 5 /U.M/10* cells, as previously described in detail [2,4]. Cultures were incubated in RPMI 1640 (10% FCS) at 37^ for 20 h. In some cases PMBC were pre-treated with Vibrio cholerae neuraminidase (NA) as previously described (50 U/ml/10ĉ ells for 1 h at 37°C) [3], before GO induction. IFN production was titrated on supernatants obtained from 20-h cultures of both unstimulated (to evaluate spontaneous production) and stimulated PBMC, on human WISH cell cultures in microplates.…”

“…Activity was measured in international units (IU) against a standard of IFN-y as previously described [4]. The antiviral activity found in the samples was identified as IFN-a or IFN-y in accordance with current criteria [3].…”

Role of calcium in gamma interferon induction: inhibition by calcium entry blockers

“…Mitogenic, as well as antigenic, stimulation of gamma interferon (gamma-IFN) production by human lymphocytes occurs through oxidation of galactose residues on the cell membrane (la, 3, 4). A role for calcium was suggested by the finding that gamma-IFN production was stimulated by the calcium ionophore A23187 (2) and that IFN induction by mitogens (3), antigens, and oxidizing agents (la) did not occur in the presence of the chelating agent ethylene glycolbis(3-aminoethyl ether)-N,N-tetraacetic acid. Moreover, IFN production was also prevented when ethylene glycolbis(,3-aminoethyl ether)-N,N-tetraacetic acid was added to the cultures after completion of the oxidative events on the cell membrane (la).…”