Interferon Production In Cultures Research Articles

Virus-induced interferon production in leukocyte cultures from children with recurrent respiratory infections. A follow-up study

Background: Lowered yields of virus-induced interferon (IFN) by leukocyte cultures were previously suggested to be associated with recurrent respiratory infections in children (Pitkäranta et al. (1993) Clin. Diagn. Virol. 1, 101–108) Objectives: To investigate if the observed lowered IFN producing capacity was secondary to the underlying disease and, consequently, would be normalized after recovery of the child from the chain of infections. Study design: Forty-eight 3–12-year-old children suffering from recurrent upper respiratory tract infections (acute otitis media included) were followed-up for 2 years. Their clinical condition and virus-induced interferon production in cultures of peripheral blood leukocytes were examined at the beginning and end of this period. Results: In 24 children the health improved strikingly during the follow-up, in 12 children a mild improvement took place, while 12 children remained constantly ill. IFN yields in cultures stimulated with corona- and respiratory syncytical viruses improved along with the clinical situation of the children. Parallel cultures induced with adeno-, influenza A or rhinoviruses did not show a similar correlation. Conclusion: These results suggest that the relationship between interferon production by leukocyte cultures and recurrent infections is complex and may be virus-specific.

Stimulation of T Cells and Induction of Interferon by Toxic Shock Syndrome Toxin 1

Toxic shock syndrome toxin 1 (TSST-1) is a potent immunomodulating substance isolated from Staphylococcus aureus strains associated with toxic shock syndrome (TSS). Flow cytometric analysis was used to compare scatter changes in several cell-surface phenotype markers on human mononuclear cells exposed in vitro to TSST-1 or to phytohemagglutinin, a lectin with similar effects on the immune response. The results showed differences between PHA and TSST-1 in the appearance of the tested T cell subset markers and of interleukin 2 receptors. In general, the stimulation of mononuclear cells by TSST-1 was slower than that by phytohemagglutinin. TSST-1 induced the production of interferon in cultures of murine spleen cells. By means of inhibition studies with specific antibodies to interferon, the interferon produced was characterized as the gamma type. Human mononuclear cells exposed to the toxin also produced gamma interferon, with levels similar to those induced by staphylococcal enterotoxin A, a known potent interferon inducer. The induction of gamma interferon by TSST-1 may play a role in the immunosuppression caused by TSST-1.

Mitogen-induced interferon production by normal and steroid-resistant mouse thymocytes.

We have investigated the proliferative response and interferon production in cultures of mouse thymocytes stimulated with two different mitogens, PHA (phytohemagglutinin), or Con A (concanavalin A). Normal thymocytes proliferated weakly and did not produce detectable interferon levels in response to both mitogens. Supplementing this cell population with macrophages or adding 2-mercaptoethanol to the culture medium strongly enhanced the proliferative response to both mitogens, but only in response to PHA marginal levels of interferon could be detected. When the steroid-resistant population was tested, both PHA and Con A induced strong proliferative responses; in this case significant interferon levels could be obtained after stimulation with PHA, but only borderline levels with Con A. Peripheral lymphocytes from the spleen responded identically to both mitogens with respect to interferon production as well as proliferation. The data suggest that distinct differentiation pathways may exist for T lymphocytes producing interferon in response to different mitogens.

Studies on the enhancement of interferon production in human diploid (FS-4) cells by ultraviolet.

Interferon production stimulated with Polyinosinate-Polycytidylate [Poly (I). Poly (C)] in cultures of human FS-4 cells was enhanced ('superinduced') by the irradiation of cells with UV at the time of induction. UV showed no additional enhancing action on interferon production in cultures already superinduced by the sequential treatment with cycloheximide and actinomycin D; UV doses above 1,000 erg/mm2 inhibited interferon synthesis. In UV-irradiated cells interferon production remained sensitive to inhibition by high concentrations of actinomycin D for at least 3 hr after exposure to Poly (I). Poly (C). Irradiation of induced cells at 4, 5 or 6 hr after stimulation with Poly (I). Poly (C) prevented the rapid decline (shutoff) of interferon synthesis seen in control cultures. All these results support the conclusion that the action of UV protects the interferon mRNA from inactivation. This effect, and the fact that interferon mRNA synthesis can occur after the irradiation of cells with superinducing doses of UV, form the basis of the enhancement of interferon production by UV.

Immunologically specific production of interferon in cultures of rabbit blood lymphocytes: association with in vitro tests for cell-mediated immunity.

Lymphocytes of animals with delayed hypersensitivity produce mediators of cellular immunity when challenged in vitro with specific antigen. Among these are macrophage migration inhibitory factor (MIF) and interferon (IF). Nonspecific mitogens also induce the production of these lymphokines. In the following study leukocytes and column-purified lymphocytes of the same peripheral blood sample from tuberculin (purified protein derivatives [PPD])-sensitive rabbits were concurrently cultured in medium alone or with PPD. Supernatants of 1- and 4-day lymphocyte cultures were assayed for MIF. Supernatants of 1-, 2- to 4- and 5- to 7-day leukocyte cultures were assayed for IF by inhibition of cytopathic effect of vesicular stomatitis virus on rabbit kidney cultures. In the presence of PPD, normal lymphocytes did not produce MIF, but lymphocytes from sensitized animals did (8/8 animals), after 1 and 4 days of culture. Leukocytes from normal animals produced little or no IF when cultured with or without PPD. Leukocytes from sensitized animals cultured in medium alone produced little IF. However, when cultured with PPD they produced significant amounts of IF on day-1 (6/8 animals) and day-2 to day-4 (4/8) animals. There was no correlation between relative amounts of MIF and IF produced by cultures of respective cells from individual animals. Rabbit IF produced or released in vitro appeared in significant and maximum amounts by 24 h coincident with the time release of significant amounts of another mediator of cellular immunity, MIF.

Increased Interferon Production in Human Cells Irradiated with Ultraviolet Light

Polyinosinate-polycytidylate [poly(I).poly(C)]-induced interferon production in cultures of human foreskin fibroblast strains was increased by ultraviolet irradiation of cells at the time of exposure to inducer or at 2 h after induction. Incubation of cells with interferon prior to induction (priming) and ultraviolet irradiation exerted a cooperative enhancing effect on interferon production. The resulting interferon yields were generally somewhat higher than the yields from cultures subjected to sequential treatment with cycloheximide and actinomycin D.

Control of interferon synthesis: effect of diethylaminoethyl-dextran on induction by polyinosinic-polycytidylic acid.

Interferon production in cultures of rabbit kidney cells (RKC) stimulated with 10 to 250 mug of polyinosinic-polycytidylic acid (poly I.poly C) per ml peaked at 3 to 4 hr after the exposure of cells to inducer and rapidly declined thereafter. On the other hand, RKC stimulated with poly I.poly C (10 or 2 mug/ml) in the presence of diethylaminoethyl (DEAE)-dextran (100 or 20 mug/ml, respectively) produced a protracted interferon response, with the release of interferon continuing for over 24 hr. The kinetics of interferon production in RKC stimulated with lower concentrations of the mixture of poly I.poly C and DEAE-dextran were similar to the response produced by poly I.poly C alone (10 to 250 mug/ml). Only the responses that terminated early were paradoxically enhanced by treatment with low doses of actinomycin D or with cycloheximide. Cells stimulated with 50 mug of poly I.poly C/ml showed hyporesponsiveness to a second interferon induction with poly I.poly C when restimulated 7 hr after primary induction. This hyporesponsiveness could be overcome by restimulating with higher concentrations of the poly I.poly C-DEAE-dextran complex. The results are compatible with the hypothesis that the early termination of interferon production and hyporesponsiveness to repeated induction with poly I.poly C are due to a cellular repressor exerting negative control on interferon synthesis, and that the increased cellular uptake of poly I.poly C in the presence of DEAE-dextran may effectively neutralize the repressor. These results also suggested that the often observed different kinetics and the varied effects of inhibitors of ribonucleic acid or protein synthesis on interferon responses in various cells and in cells stimulated with different inducers (such as with viruses as compared with polynucleotides) need not imply the existence of fundamentally different mechanisms of interferon production.

Immune specific induction of interferon production in cultures of human blood lymphocytes.

Human blood lymphocytes stimulated with nonviral antigens in vitro produce an antiviral substance with the biological and biochemical characteristics of interferon. The induced response was specific for cells obtained from immune donors. Cells from nonimmune donors did not produce interferon on exposure to these substances. The quantity of interferon produced by antigen stimulation was related to concentration of antigen over a relatively narrow range; with higher concentrations induction was decreased. Interferon production was maximum during days 4 to 7 in culture. In contrast, phytohemagglutinin-induced interferon was primarily produced during the first 4 days in culture.