Subject(s)
Herpesvirus 4, Human/pathogenicity , Interferons/biosynthesis , Vesicular stomatitis Indiana virus/pathogenicity , Antibodies, Viral/analysis , Cell Line , Cells, Cultured , Embryo, Mammalian , Female , Humans , Infectious Mononucleosis/immunology , Leukocytes/metabolism , Lymphocytes , Pregnancy , Toxoplasmosis/immunologyABSTRACT
The plasma membrane of mammalian cells can mediate the cytotoxic and cytocidal effects of colicin E3. As little as 10(2) lethal units of purified colicin E3 per cell exert a pronounced cytocidal effect on human epithelial HeLa cells and as little as 10(4) lethal units per cell also on line L mouse fibroblasts in tissue culture. Cells in complete monolayers are rapidly killed, become spherical and shrink, they are detached from the support and finally autolyzed. The percentage of killed cells in both lines is directly proportional to the multiplicity of colicin used. The LD50 for HeLa cells is about 30 times lower than for L cells. At the multiplicity of 10(5) I.u., usually 100% HeLa and 90% L cells are killed in 2--3 days. Purified colicins E2 and D have no demonstrable cytological effect on HeLa cells, although DNA synthesis in L cells appears to be partly inhibited by colicin E2. The profound effect of colicin E3 on mammalian cells could be interpreted in a similar way as in bacteria, viz. as a specific cleavage of rRNA.
Subject(s)
Cell Adhesion/drug effects , Cell Survival/drug effects , Colicins/pharmacology , Cell Division/drug effects , Cell Membrane/drug effects , HeLa Cells , L CellsABSTRACT
The ability of human peripheral blood leukocytes to produce interferon in response to phage double-stranded (ds) RNA was studied. Under the conditions used, interferon was produced not only by lymphocytes but also by polymorphs and monocytes. These "pure" cultures showed no marked differences in the degree of interferon production as compared with the mixed leukocyte culture. The involvement of polymorphs in the production of interferon induced by phage ds RNA is discussed.
Subject(s)
Interferon Inducers , Interferons/biosynthesis , Leukocytes/metabolism , RNA, Viral/pharmacology , Cells, Cultured , Coliphages , Humans , Lymphocytes/metabolism , Monocytes/metabolism , Neutrophils/metabolismABSTRACT
Physico-chemical properties of partially purified interferon produced by a mixed culture of human peripheral blood leukocytes following induction with double-stranded RNA extracted from f2 phage infected Escherichia coli were studied. Molecular heterogeneity of the interferon preparation was demonstrated by gel chromatography on a Sephadex G-100 column, disc electrophoresis in polyacrylamide gel and by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The first two methods revealed 5 peaks, the latter 7 peaks of interferon activity. There was no difference in the molecular nature of interferon produced by cultures exposed to the inducer for the whole period of incubation and that produced by cultures from which the inducer was removed after a short induction time.
Subject(s)
Interferons/biosynthesis , Leukocytes/metabolism , Cells, Cultured , Coliphages , Humans , Interferon Inducers , Interferons/analysis , Molecular Weight , Protein Conformation , RNA, Viral/pharmacologyABSTRACT
The dynamics of interferon formation by an established cell line of mouse fibroblast (L cells) and by mouse peritoneal leukocytes induced by double-stranded RNA extracted from E. coli f2 phage is described. The L cells produced interferon at a lower rate, the maximum values were obtained at 12 to 20 hours after induction, and the production was ultimately dependent on the established cell line used and on the presence of DEAE-dextran during induction. The mouse peritoneal leukocytes (MPL), on the other hand, did not require DEAE-dextran and the maximum of interferon production was reached between 6 and 12 hours after induction. Both the L cell- and the MPL-interferons were purified and concentrated so that the final specific biologic activity was 100-to 300-fold higher than that of the initial preparations (1 to 5 X 10(6) interferon units per mg protein). Polyacrylamide gel electrophoresis showed similar migration profiles for the preparations of both interferons. The smaller part of the activity was situated in a broader, slow-moving peak and the greater part formed a sharp, high and fast-moving peak. Using 3H uridine-labelled f2 ds-RNA for induction of interferon it was found that one of the radioactivity zones coincided with the fast-moving activity peak of the purified and concentrated interferon.
