Showing papers on "Interferon published in 1978"

Enhanced NK cell activity in mice injected with interferon and interferon inducers

Abstract: NATURAL KILLER (NK) cells constitute a distinct subgroup of cells within the immune system1,2. They are found in the lymphoid organs of several species including man and are cytolytic on contact in short-term in vitro assays for several cell types, in particular tumour cells1–5. Although the level of NK cell activity is under genetic control6,7, several extraneous agents, including bacterial adjuvants, animal viruses and NK-sensitive tumour cells induce an increase in in vivo NK cell activity6–10. Several of these agents are also known to increase the resistance of mice to transplantable tumours. This effect may be mediated by NK cells, as a positive correlation exists between in vivo resistance to syngeneic tumours and the levels of NK cell activity in the individual mice11,12. Viruses as well as several immunoadjuvants are also inducers of interferon. Here we present evidence that interferon and interferon inducers markedly enhance NK cell activity in mice, and suggest that interferon may be the mediator by which many different agents increase NK cell activity in vivo.

Anti-viral activity induced by culturing lymphocytes with tumor-derived or virus-transformed cells. Enhancement of human natural killer cell activity by interferon and antagonistic inhibition of susceptibility of target cells to lysis.

Abstract: Interferon, induced in lymphocytes either with viruses or cell lines, increases severalfold the natural cytotoxicity of human lymphocytes on target cell lines. Cell separation experiments support the hypothesis that interferon enhances the activity of natural killer cells rather than generating a new population of effector cells. In mixed culture of lymphocytes and cell lines in which endogenous interferon is produced, interferon mediates an enhancement of cytotoxicity that represents up to 70-90% of the observed cytotoxicity. The effect of interferon on target cells is antagonistic to the effect on the lymphocytes: the susceptibility to cell-mediated lysis of various cells upon pretreatment with interferon is decreased and in some cases almost completely suppressed. Interferon renders target cells resistant to natural killer cells acting by an intracellular mechanism which requires RNA and protein synthesis. While normal fibroblasts are protected, virus-infected cells and most tumor cells usually are not protected by interferon. Interferon by stimulating very efficient nonspecific cytotoxic cells and by protecting at the same time normal cells from lysis, might render the natural killer cell system an inducible selective defense mechanism against tumor and virus-infected cells.

Anti-viral activity induced by culturing lymphocytes with tumor-derived or virus-transformed cells. Identification of the anti-viral activity as interferon and characterization of the human effector lymphocyte subpopulation.

Abstract: A viral inhibitor(s) is released in the supernate of mixed cultures containing human or mouse lymphocytes and cells from certain lines. The inhibitor is active against a variety of unrelated viruses and is a protein that is not toxic for cells. It does not inactivate viruses directly, but inhibits viral replication through an intracellular mechanism that involves synthesis by the cells of both RNA and protein. These characteristics identify the inhibitor as an interferon. The anti-viral activity is contained in at least two molecular species, of approximately 25,000 and 45,000 daltons, respectively. In addition to the anti-viral activity, the supernates of the mixed cultures display an anti-cellular activity, the inhibition of DNA synthesis and of cell multiplication. The anti-viral and the anti-cellular activities are positively correlated in supernates from various cultures and in partially purified preparations. The human cell population responsible for interferon production is composed mainly of Fc-receptor positive, surface immunoglobulin negative, non-T-cell lymphocytes. The ability of certain cell lines to induce interferon seems to be preferentially associated with tumor origin or with in vitro transformation by certain viruses (Epstein-Barr virus, murine sarcoma virus).

Cytotoxic cells induced during lymphocytic choriomeningitis virus infection of mice. I. Characterization of natural killer cell induction

Abstract: Lymphocytic choriomeningitis virus (LCMV) infection of C3H/St, nude (BALB/c background), and other mice induced high levels of natural killer (NK) cell activity in the spleen and peritoneum. L-929 cells were used as targetsand were not lysed by spleen or peritoneal cells from uninfected mice. The cytotoxic cells were characterized as NK cells because they were nonadherent, nonphagocytic lymphocytes lacking theta and immunoglobulin antigens on their plasma membranes. Their activity was sensitive to 6 mM EDTA and to heating for 5 h at 37 degrees C, but resisted treatment with 0.5 percent trypsin. No role for antibody could be demonstrated in these assays. Relative to cytotoxic T-cell activity, the induction of NK cell activity was resistant to X-irradiation of mice with 1,000 rads but was sensitive if mice were first treated with Strontium-89, a bone-seeking isotope. NK cells were induced by LCMV in all tested strains of mice. In C3H/St mice NK cell activity was detected as early as 1 day and peaked at 3 days postinfection. Maximum activity in C3H/St mice was observed in mice 5-10 wk of age, but significant NK activity was also induced in newborns, which subsequently carried virus in their tissues for the duration of their lives. Older LCMV-carriers did not have detectable spleen NK cell activity. No memory oranamnestic response could be demonstrated for NK cell induction. NK cell activity was not induced by LCMV challenge of LCMV-immune mice, but was induced in those mice by infection with Pichinde virus, a closely related virus. The advent of NK cell activity correlated with the synthesis of interferon in LCMV-infected mice. Culture fluids lacking virus infectivity but containing interferon induced cytotoxic cell activity in nude and C3H/St mice. These experiments suggest that LCMV induced NK cells via an interferon-dependent mechanism. When studied in several strains of mice, the continued expression of NK cell activity did not seem to directly correlate with spleen interferon levels, suggesting that additional factors may play a role as well in maintaining the activity of the NK cell in vivo.

Interferon action may be mediated by activation of a nuclease by pppA2'p5'A2'p5'A.

Abstract: EXPOSURE of cells to the antiviral agent interferon inhibits virus replication1. In interferon-treated cells the adsorption, penetration and uncoating of infecting viruses is not affected, but the synthesis of virus-specific mRNA and viral proteins is inhibited2,3. We have studied a mechanism for degradation of mRNA which may be activated in interferon-treated cells by the presence of double-stranded RNA (dsRNA) of viral origin. Lengyel et al. have reported that an endonuclease present in extracts of cells treated with interferon is activated by dsRNA and ATP4–6. The endonuclease degrades mRNA by a process which can be divided into two phases: an activation phase requiring the presence of both ATP and dsRNA but not of mRNA, and an endonucleolytic phase, which does not require either ATP or dsRNA6. Kerr et al. have at the same time reported that protein synthesis is inhibited in extracts of cells treated with interferon after incubation with dsRNA and ATP7. In these incubation conditions a low molecular weight inhibitor is formed from ATP8,9. The mechanism of action of this inhibitor, the structure of which has recently been determined as pppA2′p5′A2′p5′A (pppApApA)10, is not known. Our results indicate that this trinucleotide mediates the activation of a nuclease which degrades mRNA and may therefore inhibit protein synthesis in this way.

Preliminary Observations on the Effect of Human Leukocyte Interferon in Non-Hodgkin's Lymphoma

Abstract: IN laboratory animals both endogenously induced and passively administered interferon have inhibitory effects on a wide variety of tumors, including those caused by oncogenic viruses.1 2 3 4 Such e...

Biological effects of staphylococcal enterotoxin A on human peripheral lymphocytes.

Abstract: The mitogenicity, ability to induce immune interferon, and relationship between interferon synthesis and cell proliferative response were studied using human peripheral lymphocytes stimulated by staphylococcal enterotoxin A (SEA), phytohemagglutinin-P (PHA-P), and concanavalin A (ConA) Maximum cell proliferative responses ([(3)H]thymidine incorporation) and protein synthesis ((14)C-amino acid incorporation) occurred on days 3 and 4, respectively, after stimulation by each of the three mitogens Maximal immune interferon levels were found 3 or 4 days after mitogen stimulation SEA-treated cultures produced approximately three times more interferon than did cultures stimulated with PHA-P or ConA Furthermore, SEA stimulated maximal cell proliferation over a much broader concentration range than did PHA-P and ConA (SEA, 10(-5) to 10(2) mug/ml; PHA-P, 10(1) to 10(2) mug/ml; ConA, 10(1) to 10(15) mug/ml) Interferon was also produced at maximal or near maximal levels over a broad concentration range of SEA (10(-2) to 10(2) mug/ml) Also, we found that inhibition of mitogen-induced DNA and protein synthesis to control levels by mitomycin C or cytosine arabinoside partially reduced interferon production The DNA inhibitor studies indicate that immune interferon synthesis occurs maximally in association with at least some proliferative response and that submaximal levels of interferon production occur in mitogen-treated cultures in the absence of detectable proliferation The ability of SEA to stimulate maximal DNA and immune interferon synthesis at concentrations of 35 x 10(-13) M and 35 x 10(-10) M, respectively, puts it in a potency range similar to that of hormones Thus, SEA may play an important role in gut immunity and Staphylococcus aureus infections at concentrations well below those required for emetic effects

Cell-mediated cytotoxicity against virus-infected target cells in humans. II. Interferon induction and activation of natural killer cells.

Abstract: The mechanisms by which human lymphocytes lyse virus-infected allogeneic fibroblast cultures were analyzed with particular consideration of the role of antiviral antibodies and interferon. Human cells infected with viruses were able to induce high levels of interferon upon contact with human lymphocytes. Interferon, whether produced by lymphocytes after direct infection with virus or induced upon exposure of lymphocytes to virus-infected fibroblasts, appeared to be responsible for enhancing the cytotoxic efficiency of the natural killer cell against the infected target. Activation of cytotoxic lymphocytes occurred as early as 6 hr after addition of interferon and increased up to 24 hr. Antibody-dependent cell-mediated cytotoxicity (Ab-CMC) could be easily induced by sensitization of infected target cells with antiviral antibodies and could be detected at 4 hr from the beginning of the cytotoxic test, before the effect of interferon on the natural killer cell was evident. However, the antibody-dependent effector cell was inactive after 4 hr of incubation. F(ab′)2 fragments of rabbit antihuman IgG completely inhibited Ab-CMC but did not at all affect the spontaneous cytotoxic activity of the effector cells against virus-infected target.

Enhanced expression of β2-microglobulin and HLA antigens on human lymphoid cells by interferon

Abstract: Mononuclear cells from the blood of healthy normal humans were kept in cultures under nonstimulating conditions for 16 hr in the presence or absence of human interferon. The relative quantities of HLA antigens and β2-microglobulin on the cultured cells were determined by quantitative immunofluorescence (fluorescence-activated cell sorter) and by the capacity of cells to absorb out cytotoxic antibodies against the relevant antigens. Interferons of different origin and purities enhanced the expression of HLA antigens and β2-microglobulins, whereas membrane immunoglobulins and antigens recognized by antiserum raised against human brain and T cells were the same on interferon-treated and control cells. Similar interferon effects were observed on an Epstein-Barrvirus-negative Burkitt lymphoma cell line. The enhanced expression of histocompatibility antigen subsequent to intereferon treatment was observed on B- and T-enriched lymphocyte populations and was found to be dose dependent with the optimum with “physiological” concentrations of interferon. Pretreatment of lymphocytes with interferon for 2 hr was found to be as effective as having interferon present during the total culture period. The interferon-induced enhancement of antigen expression on cells was dependent on active protein synthesis.

Spontaneous Cell-Mediated Cytotoxicity in Humans: Role of Interferon and Immunoglobulins

Abstract: Human lymphocytes secrete high levels of interferon a few hours after being cultured with certain tumorderived or virus-transformed cell lines. Interferon and interferon inducers (e.g., viruses, inducer cell lines, synthetic inducers), after short incubation with lymphocytes, increase several-fold the cytotoxicity of human natural killer cells. When lymphocytes are tested as effector cells against interferon-inducing target cell lines in an 18-hr test of spontaneous cell-mediated cytotoxicity, the enhancing effect of the interferon released in the culture medium is responsible for 80 to 90% of the total cytotoxicity observed. The ability or inability of different target cell lines to induce interferon is responsible for the apparent difference in selectivity of the cytotoxicity against various targets when fresh lymphocytes, cultured lymphcoytes, or interferon-activated lymphocytes are used as effector cells. Moreover, some of the apparently specific results obtained in competitive assays with unlabeled target cells are also dependent on the ability or inability of the competitor and target cells to induce interferon. Interferon does not increase the antibody-dependent cytotoxicity mediated by human lymphocytes, which suggests that spontaneous and antibody-dependent cell-mediated cytotoxicity are mediated by different effector cells or that a unique class of effector cells can mediate cytotoxicity with two independent mechanisms. The inability of rabbit F(ab′) 2 fragment antihuman IgG to inhibit spontaneous cell-mediated cytotoxicity, renders unlikely the possibility that the activity of the human natural killer cells is dependent on cytophilic anti-target cell antibodies adsorbed in vivo to the effector lymphocytes.

Interferon action: two distinct pathways for inhibition of protein synthesis by double-stranded RNA.

Abstract: Double-stranded RNA inhibits protein synthesis in at least two ways. It activates a protein kinase that blocks peptide chain initiation by phosphorylating the peptide chain initiation factor eIF-2 and also activates an endonuclease that inactivates different mRNAs at different rates. The protein kinase and the endonuclease have been partially purified from interferon-treated Ehrlich ascites tumor cells. The 2',5'-oligoadenylates [pppA(2'p5'A)n], found found earlier to be mediators in the activation of the endonuclease by double-stranded RNA, are not mediators in the activation of the protein kinase by double-stranded RNA.

Interferon affects both G1 and S+G2 in cells stimulated from quiescence to growth.

Abstract: THE interferons were originally described as proteins, produced by cells in response to virus infection, which could induce viral resistance in cells of the same species1. It is becoming clear that these proteins have other important biological activities2 and can inhibit cell division in both normal and malignant cells3–5. Although the phenomenon of growth inhibition by interferon is well established, data analysis of the effect in terms of the cell cycle is limited and not completely consistent. Killander et al.6 and Matarese and Rossi7, using asynchronously growing cultures of L1210 and Friend leukaemia cells respectively, have found that interferon-treated cells are delayed in both G1 and G2, and we have recently observed a similar effect of interferon on asynchronously growing MCF-7 cells8. Sokawa et al. have reported, however, that the only parameter affected in interferon-treated quiescent BALB/c 3T3 cells after serum stimulation, is their rate of entry into S (ref. 9). It is possible that the effect of interferon on the cell cycle of asynchronous transformed cells is different, in terms of cell cycle parameters, from its effect on quiescent untransformed cells. In an attempt to clarify this point, we have examined in detail the effect of interferon on the passage of serum-stimulated cells through the cell cycle, using BALB/c 3T3 and Swiss 3T3K cells, and a strain of human embryo lung diploid fibroblasts, HEL 27. In contrast to Sokawa et al., we have found that both G1 and S+G2 are extended by interferon treatment of all three cell types studied.

Inhibition of protein synthesis by 2′–5′ linked adenine oligonucleotides in intact cells

Abstract: A SERIES of 2–5 linked oligoadenylic acid triphosphate (2–5A) inhibitors of cell-free protein synthesis are formed from ATP by an enzyme (2–5A synthetase) activated in interferon-treated cell extracts or rabbit reticulocyte lysates by double-stranded RNA1–4. The major active species is the trimer, pppA2′p5′A2′p5′A. Cell-free protein synthesis is inhibited by subnanomolar concentrations of 2–5A and this inhibition seems to be mediated at least in part, by a nuclease which degrades mRNA5. However, 2–5A, the nuclease and the inhibition of protein synthesis are all unstable in cell-free systems. 2–5A is rapidly degraded in such systems prepared from control (or interferon-treated) cells, nuclease activity is transient and in the absence of a 2–5A regenerating system protein synthesis resumes if fresh mRNA is added6,7. Extracts derived from cells that have never been treated with interferon, therefore, have mechanisms for the synthesis of 2–5A (rabbit reticulocytes) and for responding to and degrading 2–5A. Thus, the 2–5A system, in addition to any role it has in the antiviral action of interferon, may also be involved in the regulation of normal cell growth and development. The extraordinary potency of 2–5A and its instability in cell-free systems makes the task of detecting 2–5A in intact cells very difficult. As an alternative we have studied the effect of exogenous 2–5A on protein synthesis in intact cells, using a recently described method for making animal cells reversibly permeable to small molecules8. Here we report that pppA2′p5′A2′p5′A and related 2′–5′ linked oligonucleotides inhibit protein synthesis in hypertonically treated BHK–21 cells.

The macrophage as a secretory cell.

Abstract: Publisher Summary This chapter discusses the macrophage as a secretory cell. The macrophage was one of the first cell types to be established successfully in primary culture, and it has been used extensively for the study of a wide variety of biological phenomena. In addition to the functions of tissue debridement and phagocytosis and killing of microorganisms, macrophages also participate in numerous other activities including (1) stimulation of leukocyte stem-cell growth, (2) production and release of numerous humoral substances which are active in various host–defense mechanisms, including complement, pyrogen, interferon, and factor(s) chemotactic toward neutrophils, (3) interaction with immunocompetent lymphoid cells during humoral and cell-mediated immune responses and in some immunopathological processes, (4) regulation of the replicative and synthetic activities of fibroblasts, (5) destruction of malignant cells, (6) production and secretion of substantial quantities of hydrolytic enzymes including acid hydrolases, neutral proteinases, and lysozyme, and (7) production and release of various prostaglandins and cyclic nucleotides.

Natural cell-mediated cytotoxicity in rats. II. In vivo augmentation of NK-cell activity.

Abstract: Natural cell-mediated cytotoxicity in rats as well as in mice has been shown to vary consistently with age, with peak levels detectable at 5-10 weeks. The levels of cell-mediated cytotoxicity against tumor cells could be augmented in strains of inbred rats with either high or low levels of natural reactivity, by IP injection of a variety of agents, including C. parvum, LCMV, KRV, and poly I:C. The specificity of the augmented cytotoxicity appeared to be the same as the specificity of natural killer cells which are found in normal rat spleen cells. Similarly, the cells mediating the augmented cellular cytotoxicity were small, non-adherent, esterase-negative lymphocytes with Fc receptors, as are rat NK cells. The kinetics and organ distribution of the augmentation of NK activity by poly I:C and C. parvum were compared and the kinetics were found to differ, with a shorter time course of augmented activity seen after inoculation with poly I:C. These data indicate that interferon may play a central role in the augmentation of NK activity in vivo.

Interferon and spontaneous cytotoxicity in man. I. Enhancement of the spontaneous cytotoxicity of peripheral lymphocytes by human leukocyte interferon

Abstract: A purified preparation of human leukocyte interferon used at this hospital in the treatment of malignant diseases was tested for its ability to modify the spontaneous cytotoxicity of peripheral lymphocytes from healthy donors. The inhibitory effect of allogeneic lymphocytes on the (3H)thymidine incorporation of a lymphoblastoid cell line, Raji, was augmented by the presence of interferon or by pretreatment of the lymphocytes with interferon. This form of pretreatment also increased lymphocytes' capacity for reducing the number of surface-adherent tumor cells in a microassay. Moreover, lymphocytes treated with interferon exhibited an enhanced cytotoxic capacity for target cells on incubation with such cells labelled with 51CR.

Human leukocyte interferon purified to homogeneity.

Abstract: One of the species of human interferon produced by incubation of leukocytes with Newcastle disease virus was purified to homogeneity. It exhibited one peak of activity coinciding with a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Inhibition of Murine Osteogenic Sarcomas by Treatment With Type I or Type II Interferon

Abstract: Interferon was used to treat C57BL/6 female mice inoculated with a continuous line of murine osteogenic sarcoma cells. A short 7-day course of 30,000--60,000 U/day of tpe I interferon either completely inhibited or delayed the appearance of tumors in experimental animals. The therapeutic efficacy of type I interferon was compared with murine serum that contained type II interferon as well as other lymphokine activity. Tumor development was strikingly inhibited in animals treated for 7 days with serum containing only 600 U of type II interferon. Inhibition of tumor development was thus achieved with 100-fold less interferon than that required with type I preparation.

Inhibition by lymphoblastoid interferon of growth of cells derived from the human breast

Abstract: Human lymphoblastoid interferon inhibited the growth in vitro of fibroblasts and epithelial cells from normal, hyperplastic and neoplastic human breast tissue. At an interferon concentration of 10(3) inter-national units (IU) per ml, the inhibitory effects on monolayer growth were completely reversible but the growth potential of cells at lower density in colony-forming cultures was not completely recovered. Studies on the cell cycle distribution of interferon-treated cells demonstrated that the growth-inhibitory effect was not due to an effect on one specific phase of the cell cycle, but to a lengthening of all phases.

Selective impairment of lymphocyte reactivity to varicella-zoster virus antigen among untreated patients with lymphoma.

Abstract: Herpes zoster is a frequent complication of lymphoreticular malignancy. In this study two assays of in vitro cellular immune response to varicella-zoster virus (VZV) antigen, lymphocyte transformation and interferon production, were performed in normal subjects with recent and remote VZV infection. The responses of patients with lymphoma were measured before treatment and during long-term remission and then compared with those of normal subjects. Despite levels of antibody to VZV that were equivalent to those in normal subjects, 44% of the untreated lymphoma patients showed a lower transformation response to VZV antigen than the normal patients. Production of interferon in response to VZV antigen was absent in 32% of the untreated patients. In contrast, lymphocyte responses in untreated patients to herpes simplex virus antigen were within the range observed in a normal population. Interferon production by lymphocytes in response to cytomegalovirus antigen was also lower among untreated lymphoma patients than among normal patients, but lymphocyte transformation was not. Twenty-two percent of lymphoma patients in long-term remission continued to have diminished cellular immune responses to VZV antigen. Observations in these patient populations and in normal subjects with acute herpes zoster suggest that deficiencies in in vitro lymphocyte responses may correlate with increased susceptibility to clinical infection with VZV.

Role of Interferon in the Pathogenesis of Viral Diseases of Mice As Demonstrated by the Use of Anti-Interferon Serum: V. Protective Role in Mouse Hepatitis Virus Type 3 Infection of Susceptible and Resistant Strains of Mice

Abstract: Potent sheep anti-mouse interferon globulin has been used to determine the role of virus-induced interferon in mouse hepatitis virus type 3-infected susceptible (C57BL/6), semiresistant (C3H/He), and resistant (A/J) strains of mice. Injection of anti-interferon globulin accelerated the onset of death in C57BL/6 mice, induced almost 100% mortality in C3H/He mice that usually do not die of acute disease, and caused death in 4- and 6-week-old A/J mice, but not in older mice. We conclude that interferon is an important host defense factor in the initial response of different strains of mice to MHV-3 infection. Other factors, however, such as the capacity of macrophages to restrict viral multiplication probably underlie the genetically determined susceptibility or resistance of mice to MHV-3 infection.

Relationships of the structure and function of the interferon receptor to hormone receptors and establishment of the antiviral state.

Abstract: This report describes similarities between the structure and function of the interferon receptor and receptors for glycoprotein hormones and several bacterial toxins. Specifically, it describes several common molecular and mechanistic elements, including: ( a ) the presence of a glycoprotein as well as a ganglioside component in the receptor; ( b ) changes in membrane structure as a consequence of interferon action; ( c ) interferon-induced intracellular cyclic adenosine 3′:5′-monophosphate changes; and ( d ) alterations in the flux of certain ions across the membrane. Since interferon has an antiviral effect, these results define a relationship between hormonal perturbation of cellular events and the ability of an agent to prevent or suppress viral infections of cells. Further definition of these relationships should be important to our understanding of the oncogenic state, of hormonal effects on the oncogenic state, and of other human diseases in which hormonal perturbations of non-target tissues or cross-reactivity of receptors could be pathogenic.

Similarities among factors that render macrophages tumoricidal in lymphokine and interferon preparations.

Abstract: Lymphokine preparations, including supernatants derived from antigen-stimulated Bacillus Calmette-Guerin -immune spleen cell cultures and normal spleen cells incubated with insoluble concanavalin A, were compared with partially purified L-cell interferon for the ability to render resting macrophages nonspecifically tumoricidal in vitro . Significant activation of macrophages by lymphokine preparations occurred at concentrations as low as 0.5 and 0.25% of the assay mixture for antigen-stimulated and concanavalin A-induced lymphokine, respectively. These end point concentrations were each determined to contain 0.3 unit of interferon per ml. Supernatants obtained from unstimulated normal spleen cells, concanavalin A-treated nu/nu spleen cells, or Bacillus Calmette-Guerin -immune spleen cells in the absence of sensitizing antigen did not enhance macrophage tumoricidal function and lacked interferon. Activation by L-cell interferon required at least 1 unit/ml. The macrophageactivating factors contained in lymphokine and interferon preparations were stable at pH 2 and at 56°, but they wee destroyed when heated at 80° for 30 min, and were inactivated by trypsin. The data demonstrate common properties for the induction of tumoricidal macrophages by these divese preparations.