Biomedical subjects

B Y Rubin

Publications and source records attributed to B Y Rubin.

At least 37 records · Page 2Linked to original sources

PubMed1988

Correlation between the anticellular and DNA fragmenting activities of tumor necrosis factor.

The treatment of cells sensitive to the anticellular effect of tumor necrosis factor (TNF) with TNF results in a degradation of their cellular DNA into DNA fragments that are multiples of 200 base pairs. TNF treatment of cells resistant to the anticellular effect of TNF, but bearing receptors for TNF, fails to result in any DNA fragmentation. Incubation conditions, such as temperature, the presence of metabolic inhibitors or amino acid deprivation, that modulate the effectiveness of TNF or affect the rate at which TNF exerts its anticellular effect have a similar effect on the ability of the TNF to generate DNA fragments. Thus the TNF-mediated DNA fragmentation and the rate at which it occurs correlates with the rate at which cells respond to the anticellular effect of TNF and, as such, might serve as a marker for the responsiveness of cells to TNF.

Antineoplastic Agents↗

PubMed1988

Tumor necrosis factor and IFN induce a common set of proteins.

The treatment of cells with TNF or IFN results in the development of an antiviral state and in the induction of a common set of proteins with m.w. of 80,000, 67,000, and 56,000. The induction of the 80,000- and 56,000-Da proteins after TNF treatment is dependent on the synthesis of an intermediary protein, whereas the induction of the 67,000-Da protein appears to occur as a direct result of the TNF treatment. The effects of antibodies to IFN on the TNF-mediated effects have been evaluated and reveal that the incubation of TNF-treated cells with antibody to rIFN-beta 1 greatly reduces the antiviral effectiveness of the TNF treatment and blocks the ability of TNF to induce the 80,000-Da protein. Incubation with antibodies to either IFN-alpha or IFN-gamma failed to affect the TNF-mediated responses. Thus, the induction by TNF of each of the proteins is regulated differently and is mediated through both IFN-dependent and IFN-independent mechanisms.

Animals↗

PubMed1988

Role of L3T4+ and LyT-2+ cells in experimental visceral leishmaniasis.

In contrast to euthymic (nu/+) BALB/c mice, athymic nude (nu/nu) BALB/c mice fail to control the visceral intracellular replication of Leishmania donovani, do not generate the macrophage-activating lymphokine IFN-gamma, and show little or no granulomatous tissue response. To characterize the T cell requirement for successful defense against L. donovani, nude mice were first reconstituted with unfractionated nu/+ immune spleen cells, which readily conferred the capacity to control and eliminate visceral (hepatic) L. donovani. In reconstituted mice, acquired resistance was paralleled by the ability of spleen cells to generate high levels of leishmanial Ag-stimulated IFN-gamma and the development of well formed liver granulomas. In contrast, nude mice reconstituted with either L3T4+- or Lyt-2+-enriched immune spleen cells alone failed to control visceral parasite replication and did not develop effective granulomas despite the finding that transfer of L3T4+ cells largely and Lyt-2+ cells partially restored the capacity to secrete IFN-gamma. To determine whether both T cell subsets were also required in a normal host, nu/+ BALB/c mice were treated with cell-depleting anti-L3T4 and anti-Lyt-2 mAb. Depletion of either T cell subset inhibited the acquisition of resistance to L. donovani and impaired the tissue granulomatous response. Thus, successful T cell-dependent host defense towards intracellular L. donovani and the tissue expression (granulomas) of this mechanism appear to require both L3T4+ and Lyt-2+ cells. A primary role for the L3T4+ cell may be IFN-gamma production; the role of the Lyt-2+ cell and the precise interaction of the two T cell subsets remain to be identified.

Animals↗

PubMed1988

The development of antibody to the interferon-induced indoleamine 2,3-dioxygenase and the study of the regulation of its synthesis.

Interferon (IFN) treatment of cells induces the synthesis of several new proteins. Antibody to the IFN-induced 42,000 dalton protein has been prepared and used in the study of this protein. The synthesis of the 42,000 dalton protein is dependent on de novo RNA synthesis, as its induction can be blocked if actinomycin D and the IFN are added to the cells simultaneously. Several lines of evidence suggest that the IFN-induced 42,000 dalton protein is the IFN-induced indoleamine 2,3-dioxygenase (IDO). These are as follows: 1) antibody to the 42,000 dalton protein neutralizes the activity of the IDO; 2) examination of a variety of cell lines reveals a correlation between the presence of this protein and the presence of the IDO; and 3) the induction of both the IDO and the 42,000 dalton protein is blocked under conditions in which the IFN treatment is performed in the presence of cycloheximide, and actinomycin D is added to the cells prior to the removal of the cycloheximide. A study of a variety of cell lines has revealed that the induction of the IDO occurs primarily in response to IFN-gamma. Peripheral blood mononuclear cells (PBMC) were the only cell population in which IFN-alpha and IFN-gamma were observed to produce the IDO. The IDO activity induced in IFN-alpha and IFN-gamma treated PBMC is neutralized by antibody to the 42,000 dalton protein, thus demonstrating that the IDO activity induced in these cells by IFN-alpha and IFN-gamma is mediated by the same molecule or antigenically related molecules. Fractionation of the PBMC populations reveals that it is the monocyte that produces the IFN-induced IDO.

Antibody Formation↗

PubMed1988

Production of a monoclonal antibody directed against an interferon-induced 56,000-dalton protein and its use in the study of this protein.

Interferon (IFN) treatment of cells induces the synthesis of several new proteins. A hybridoma cell line producing monoclonal antibody to the IFN-induced 56,000-dalton protein has been developed. The IFN-induced 56,000-dalton protein is synthesized by a variety of different cells and in response to IFN-alpha, IFN-beta, and IFN-gamma. The induction of this protein is dependent on de novo RNA synthesis, since its induction is inhibited if actinomycin D and the IFNs are added to the cells simultaneously. Labeling of IFN-treated cells at 4-h intervals at various times after the addition of the IFNs reveals that the synthesis of the 56,000-dalton protein in IFN-alpha-treated cells peaks within 12 h after the addition of the IFN and is no longer enhanced 20 h after exposure to the IFN. In contrast, IFN-gamma-treated cells continue to show an enhanced synthesis of this IFN-induced protein even after 20 h of exposure to the IFN. Thus, the synthesis of the IFN-induced 56,000-dalton protein is regulated differently by the different IFNs. When cells are treated with IFN-alpha or IFN-gamma in the presence of cycloheximide, and actinomycin D is added prior to the removal of the cycloheximide, the cells produce the IFN-induced 56,000-dalton protein and develop an antiviral state in response to both IFN-alpha and IFN-gamma. These results demonstrate that the synthesis of the 56,000-dalton protein is not dependent on the synthesis of an intermediary protein and that the establishment of an antiviral state occurs in the absence of multiple transcriptional events.

Adaptor Proteins, Signal Transducing↗

PubMed1988

T4+ cell production of interferon gamma and the clinical spectrum of patients at risk for and with acquired immunodeficiency syndrome.

To fully characterize the relationship between the clinical manifestations of human immunodeficiency virus infection and T4+ cell defects, we determined T4+ cell number and interferon gamma (IFN-gamma) production in 238 patients. For asymptomatic homosexuals, patients with acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and patients with fully established AIDS, clinical status correlated linearly with both T4+ cell number and T4+ cell-derived (antigen-stimulated) IFN-gamma secretion. For asymptomatic homosexuals, abnormalities in T4+ cell number and IFN-gamma generation were similar irrespective of human immunodeficiency virus seropositivity. For patients with ARC, those with lymphadenopathy (LA) alone or LA plus zoster or thrombocytopenia displayed T4+ cell defects similar to those observed in asymptomatic homosexuals. Patients with ARC with LA plus constitutional symptoms and/or oral thrush, however, had fewer T4+ cells, were strikingly more deficient in IFN-gamma production, and closely resembled those with AIDS. Among patients with AIDS, certain individuals with Kaposi's sarcoma (KS) alone were sufficiently less cytopenic and less immunodeficient than patients with opportunistic infections (Ols) to suggest that the immune impairment that predisposes to KS may differ. At the time patients with KS developed Ols, however, T4+ cell number and IFN-gamma-generating capacity had declined to the remarkably low levels observed in virtually all patients with Ols alone.

AIDS-Related Complex↗

PubMed1987

Experimental visceral leishmaniasis: production of interleukin 2 and interferon-gamma, tissue immune reaction, and response to treatment with interleukin 2 and interferon-gamma.

During the first 2 to 4 weeks of progressive visceral infection with the intracellular protozoan, Leishmania donovani, spleen cells from BALB/c mice failed in response to leishmanial antigen to produce either of the activating T cell-derived lymphokines, interleukin 2 (IL 2) or gamma-interferon (IFN-gamma). Four weeks after infection, however, antigen-induced IL 2 and IFN-gamma secretion emerged and coincided with the onset of control over parasite replication and the subsequent killing of greater than 80% of intrahepatic L. donovani. The development of this immunosecretory activity correlated with the hepatic tissue response at the site of parasitized Kupffer cells. This response progressed from Kupffer cell fusion (week 1) to fusion plus a mononuclear cell infiltrate (week 2) to well-organized granuloma formation (weeks 4 to 8). In contrast, T cell-deficient nude BALB/c mice exerted no control over L. donovani, their spleen cells failed to generate antigen-induced IFN-gamma, and at 4 weeks, their livers were devoid of any tissue reaction. Since spleen cells from 2-week infected normal mice did not produce antigen-stimulated IL 2 or IFN-gamma, these mice were treated with recombinant (r) lymphokines. Various protocols using both high and low dose human rIL 2 had no antileishmanial effect. Hepatic parasite replication was completely halted, however, by macrophage-activating doses of murine rIFN-gamma. These results reemphasize that an intact T cell-dependent response is required for successful defense against L. donovani, indicate that this immune response can be measured at both the cellular (secretory) and tissue levels, and confirm that IFN-gamma can exert an antileishmanial effect in vivo.

Animals↗

PubMed1987

The role of gamma interferon in the generation of human macrophages cytotoxic for Entamoeba histolytica trophozoites.

Upon exposure to Entamoeba histolytica antigen, lymphocytes from patients treated for amebic liver abscess produce lymphokines which activate monocyte-derived macrophages to kill E. histolytica trophozoites. We now demonstrate that gamma interferon (IFN-gamma) is produced by these stimulated lymphocytes and is sufficient but not exclusively necessary to activate monocyte-derived macrophage amebicidal activity. Supernatants from mononuclear cells of 7 patients when stimulated with amebic antigen contained more IFN-gamma than comparable supernatants derived from control cells (1,862 U/ml vs. 174 U/ml geometric means, P less than 0.01); IFN-gamma levels were similar in patient and control supernatants following concanavalin A stimulation. Macrophages activated solely by partially purified IFN-gamma or recombinant human IFN-gamma (300 U/ml) killed 47% of virulent amebae by 6 hr at 37 degrees C. Monocyte-derived macrophages stimulated with lymphokines elicited by amebic antigen or concanavalin A killed 48% and 57% of axenic E. histolytica trophozoites, respectively, over 6 hr at 37 degrees C (P less than 0.001 for each compared to control). Macrophages incubated with the identical lymphokines, but in the presence of monoclonal antibody to IFN-gamma, were only able to kill 18% and 27% of amebae, respectively, at 6 hr (P less than 0.05 to control or when antibody to IFN-gamma was not present). If antibody to IFN-gamma was added to the stimulating lymphokine, more macrophages died during interaction with amebae (P less than 0.05). In summary, IFN-gamma has a major but not exclusive role in activating human monocyte-derived macrophages in vitro to kill virulent E. histolytica trophozoites.

Adult↗

PubMed1986

Nonhematopoietic cells selected for resistance to tumor necrosis factor produce tumor necrosis factor.

TNF-resistant lines of L cells can be derived from TNF-sensitive populations by repeated exposure to TNF, and these resistant L cells, in contrast to sensitive L cells and other types of cells, lack demonstrable cell surface receptors for TNF. We have now found that TNF-resistant L cells produce a factor that is cytotoxic for L cells and has the following distinguishing characteristics of mouse TNF: it is a protein of 43 kD, composed of 16 kD subunits, that competes with TNF for receptor binding, induces hemorrhagic necrosis of the TNF-sensitive mouse sarcoma Meth A, has synergistic cytotoxic action with interferon, and its activity is neutralized by antibody to TNF. The two conclusions of this study are that cells selected for TNF resistance spontaneously produce a molecule resembling macrophage TNF, and that cells of nonhematopoietic origin are capable of producing TNF.

Animals↗

PubMed1986

Oxygen-independent inhibition of intracellular Chlamydia psittaci growth by human monocytes and interferon-gamma-activated macrophages.

We have demonstrated previously that Chlamydia psittaci grows well in human monocyte-derived macrophages, but to a limited extent in lymphokine-or interferon-gamma (IFN-gamma)-activated macrophages. In this investigation, freshly explanted human monocytes inhibited chlamydial inclusion formation by 85% as compared to macrophages, and the level of inhibition was similar to that exhibited by lymphokine-activated macrophages (79%). To determine whether the oxygen-dependent antimicrobial mechanisms of the mononuclear phagocyte were involved in the inhibition, cells were infected with C. psittaci in the presence of agents that either inhibit the respiratory burst (glucose deprivation) or diminish the effect of H2O2 (catalase). These treatments had no effect on the capacity of monocytes and lymphokine-activated macrophages to restrict chlamydial growth. In addition, monocytes and activated macrophages from an individual with chronic granulomatous disease suppressed chlamydial growth as effectively as normal cells. Oxidatively deficient HeLa and endothelial cells, once stimulated by lymphokine, also displayed normal levels of antichlamydial activity. The induction of this apparently oxygen-independent antichlamydial effect by lymphokine was completely neutralized by a monoclonal anti-IFN-gamma antibody, and could be achieved by treatment with recombinant (r)IFN-gamma alone. These results indicate that the primary antimicrobial mechanism of the human monocyte against C. psittaci is oxygen-independent, and that this response can be effectively stimulated in the macrophage by lymphokine (IFN-gamma).

Antibodies, Monoclonal↗

PubMed1986

The suppressive influences of human tumor necrosis factors on bone marrow hematopoietic progenitor cells from normal donors and patients with leukemia: synergism of tumor necrosis factor and interferon-gamma.

The influences of human tumor necrosis factor (TNF) (LuKII), recombinant human TNF-alpha, natural human interferon-gamma (HuIFN-gamma), recombinant HuIFN-gamma, and natural HuIFN-alpha were evaluated alone or in combination for their effects in vitro on colony formation by human bone marrow granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells incubated at 5% CO2 in lowered (5%) O2 tension. TNF (LuKII) and recombinant TNF-alpha caused a similar dose-dependent inhibition of colony formation from CFU-GM, BFU-E, and CFU-GEMM. Day 7 CFU-GM colonies were more sensitive than both day 14 CFU-GM colonies and day 7 CFU-GM clusters to inhibition by TNF. BFU-E colonies and CFU-GEMM colonies were least sensitive to inhibition with TNF. The suppressive effects of TNF (LuKII) and recombinant TNF-alpha were inactivated respectively with hetero-anti-human TNF (LuKII) and monoclonal anti-recombinant human TNF-alpha. The hetero-anti-TNF (LuKII) did not inactivate the suppressive effects of TNF-alpha and the monoclonal anti-recombinant TNF-alpha did not inactivate TNF (LuKII). The suppressive effects of TNF did not appear to be mediated via endogenous T lymphocytes and/or monocytes in the bone marrow preparation, and a pulse exposure of marrow cells with TNF for 60 min resulted in maximal or near maximal inhibition when compared with cells left with TNF for the full culture incubation period. A degree of species specificity was noted in that human TNF were more active against human marrow CFU-GM colonies than against mouse marrow CFU-GM colonies. Samples of bone marrow from patients with non-remission myeloid leukemia were set up in the CFU-GM assay and formed the characteristic abnormal growth pattern of large numbers of small sized clusters. These cluster-forming cells were more sensitive to inhibition by TNF than were the CFU-GM colonies and clusters grown from the bone marrow of normal donors. The sensitivity to TNF of colony formation by CFU-GM of patients with acute myelogenous leukemia in partial or complete remission was comparable with that of normal donors. When combinations of TNF and HuIFN were evaluated together, it was noted that TNF (LuKII) or recombinant TNF synergized with natural or recombinant HuIFN-gamma, but not with HuIFN-alpha, to suppress colony formation of CFU-GM, BFU-E, and CFU-GEMM from bone marrow of normal donors at concentrations that had no suppressive effects when molecules were used alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1986

A high-affinity monoclonal antibody (GIF-1) to human gamma-interferon: neutralization of interferon mediated inhibition of retrovirus production and 2'-5' (A) synthetase induction.

An hybridoma clone secreting an IgG1 monoclonal antibody (GIF-1) specific for human gamma-interferon (HuIFN-gamma) has been generated using HAT medium supplemented with insulin (HIAT) at the initial stage of cell fusion. This antibody is capable of neutralizing the antiviral activity of HuIFN-gamma, the ability of HuIFN-gamma to inhibit retroviral replication in RD-114 cells, and the ability of HuIFN-gamma to induce the 2'-5' oligoadenylate (A) synthetase in RD-114 and HeLa cells. Eluate from an immunoaffinity column containing GIF-1 yielded two protein bands of molecular weight of 20 and 25 kd when subjected to SDS-PAGE.

2',5'-Oligoadenylate Synthetase↗

PubMed1986

Gamma interferon induces colony-forming cells of the human monoblast cell line U937 to respond to inhibition by lactoferrin, transferrin, and acidic isoferritins.

Human gamma interferon (HuIFN gamma) was assessed for its capacities to induce MHC class-II antigens on U937 cells and to induce responsiveness of U937 colony-forming cells (CFC) to the suppressive influences of lactoferrin (LF), transferrin (TF), and acidic isoferritins (AIF). U937 cells grown in suspension culture for many years demonstrated variable percentages of MHC class-II antigen+ cells (6%-42%) as determined by analysis with monoclonal anti-MHC class-II and the FACS IV when checked at different times. The percentage of U937 cells positive for MHC class-II antigens, as well as the density distribution of MHC class-II antigens on these cells, was increased by preincubating the cells for 72 h in the presence of 10(-6) M indomethacin and increasing concentrations of natural HuIFN gamma up to 20-40 U/ml. Colony formation by cells preincubated in control medium plus indomethacin for 72 h was not decreased by treating cells with monoclonal anti-MHC class-II plus complement (C'), high specific activity tritiated thymidine (3HTdr), LF, TF, or AIF. After preincubation of U937 cells with natural HuIFN gamma plus indomethacin in suspension culture for 72 h, colony formation in semisolid medium was reduced 40%-50% by treating the cells with anti-MHC class-II plus C', 3HTdr, LF, TF, or AIF. Colony formation was not reduced further by LF, TF, or AIF, after cells were pretreated with anti-MHC class-II (1:200 dilution) plus C' or 3HTdr. Increasing concentrations of HuIFN gamma up to 20 U/ml increased the percentage of MHC class-II antigen+ U937 CFC as well as the sensitivity of U937 CFC to suppression by LF, TF, and AIF. The inducing activities of natural HuIFN gamma were due to the IFN gamma itself since the inducing activity of natural HuIFN gamma was inactivated by pretreatment with a monoclonal antibody against natural HuIFN gamma. Also the inducing effects were mimicked by recombinant HuIFN gamma. The suppressive effects of LF, TF, and AIF on colony formation were blocked by treating the cells with monoclonal anti-MHC class-II (1:50 dilution, but not 1:200 dilution) in the absence of C'. The suppressive effect of TF only was blocked by pretreating cells with a monoclonal antibody against the TF receptor. U937 cells can be used as a model to study the regulatory mechanisms of action of HuIFN gamma, LF, TF, and AIF.

Cell Line↗

PubMed1986

Prostaglandin E counteracts the gamma interferon induction of major histocompatibility complex class-II antigens on U937 cells and induction of responsiveness of U937 colony-forming cells to suppression by lactoferrin, transferrin, acidic isoferritins, and prostaglandin E.

The established human monoblast or early monocyte cell line, U937, was evaluated for modulating influences of prostaglandin E2 (PGE2) on human gamma interferon (HuIFN gamma) induction of MHC class-II (Ia) antigens on U937 cells and the HuIFN gamma induction of responsiveness of U937 colony-forming cells (CFC) to inhibition by lactoferrin (LF), transferrin (TF), acidic isoferritins (AIF), and prostaglandin E (PGE). U937 CFC were induced to a state of responsiveness to the suppressive influences of PGE by HuIFN gamma. When MHC class-II antigens were induced on U937 cells and the cells sorted on the fluorescence activated cell sorter (FACS) IV into positive and negative cells, colony formation by the MHC class-II antigen+ population of cells was suppressed by LF, TF, AIF, and PGE2. Colony formation by the sorted population of MHC class-II antigen- cells was not influenced significantly by LF, TF, AIF, or PGE2. When PGE was present in the suspension culture for 72 h with U937 cells exposed to HuIFN gamma plus indomethacin, it blocked the induction of MHC class-II antigens as well as the associated inhibition of U937 CFC by LF, TF, AIF, and PGE2.

Cell Line↗

PubMed1986

Regulation of the proliferation of the established human monoblast cell line, U937, at the single cell level.

U937 cells, an established monoblast or early monocyte cell line, were assessed as a model in vitro for the regulation of cell growth at the single cell level. Colony formation by 500 U937 cells, preinduced to a state of responsiveness to lactoferrin (LF) by incubation with human gamma interferon was suppressed by LF. LF-suppressed colony formation was restored by partially purified growth activity derived from U937 cells. The release of growth factor(s) into conditioned medium required concentrations of greater than 500 U937 cells/ml and this release was dependent on the length of time that the cells conditioned the culture medium. This release was suppressed by LF. U937 cells were induced to a state of responsiveness to LF by incubation with human gamma interferon, washed, and plated as a single cell per well. Individual cells formed colonies with a cloning efficiency of approximately 50% which equalled the cloning efficiency detected when 500 U937 cells/ml were plated, suggesting that U937 colony forming cells might contain endogenous growth activity. Detection of these endogenous growth activities required the use of LF. The cloning efficiency of individually isolated U937 cells was suppressed by approximately 50% with LF, similar to the LF suppression of colony formation when 500 cells/ml were plated. That the LF-suppressed U937 colony forming cells required growth activity was suggested as the cloning efficiency of LF-suppressed individually isolated U937 colony forming cells was restored by partially purified U937 growth activity. Partially purified U937 growth activity did not stimulate, enhance, or inhibit colony formation by normal human bone marrow granulocyte-macrophage progenitors. U937 cells can thus serve as a useful model for the study of growth regulation at the level of a single cell.

Cell Cycle↗

PubMed1986

Human gamma interferon enhances release from phytohemagglutinin-stimulated T4+ lymphocytes of activities that stimulate colony formation by granulocyte-macrophage, erythroid, and multipotential progenitor cells.

Human gamma interferon (HuIFN gamma) was evaluated for its effects on the release from human peripheral blood T lymphocytes (greater than 98% pure) stimulated by phytohemagglutinin (PHA) of activities that can stimulate granulocyte-macrophage (CFU-GM) colonies and clusters, erythroid (BFU-E) bursts, and mixed (CFU-GEMM) colonies. T lymphocytes did not release these activities in the absence of PHA with or without HuIFN gamma. In the presence of PHA, pure natural HuIFN gamma at concentrations of 0.1 to 100 U/mL significantly enhanced release of these colony-stimulating activities. Although enhanced release of granulocyte-macrophage colony-stimulating activities were noted when T lymphocytes were added to the conditioning medium in the presence of 0.1%, 0.5%, and 1% PHA, enhanced release of burst-promoting and mixed colony activities was seen only in the presence of 0.1% and 0.5% PHA. The enhanced release of colony-stimulating activities was not due to HuIFN gamma-suppression of the release from PHA-stimulated T lymphocytes of suppressor molecules. The enhancing effects of natural HuIFN gamma were neutralized with a monoclonal anti-natural HuIFN gamma, and recombinant HuIFN gamma mimicked the enhancing effects of the natural HuIFN gamma. This enhancing effect was noted only when HuIFN gamma was added with the T lymphocytes and PHA during the first 24 hours of incubation. T lymphocytes were separated into T4+, T8-, T8+, and T4- subsets (greater than 98% pure for the appropriate phenotypes) after incubation with OKT4- and OKT8- monoclonal antibodies and sorting on a fluorescence-activated cell sorter (FACS). All types of colony-stimulating activities were released from each population after stimulation with PHA, but enhanced release of these activities in the presence of HuIFN gamma was only detected with the T4+ or T8- subsets of lymphocytes. It cannot be concluded from these studies whether HuIFN gamma is enhancing the release of one or several types of colony-stimulating activities, but these studies suggest a role for HuIFN gamma and T4+ lymphocyte subsets in the regulation in vitro of the release of colony-stimulating activities.

Colony-Forming Units Assay↗

PubMed1986

Activities derived from established human myeloid cell lines reverse the suppression of cell line colony formation by lactoferrin and transferrin.

Myeloid cell lines were evaluated for the release of substances needed for colony formation by their own colony-forming cells (CFC) and by other myeloid cell lines. Dialyzed U937 conditioned medium (CM) had no effect on the cloning efficiency of U937 cells, whether or not U937 CFC had been induced for MHC class-II antigens by preincubation of these cells for 72 h with indomethacin and human gamma interferon (HuIFN gamma). Dialyzed U937 CM, however, restored colony formation of HuIFN gamma-induced U937 cells suppressed by lactoferrin (LF) or transferrin (TF). Dialyzed U937 CM did not restore colony formation of U937 cells suppressed by acidic isoferritins (AIF) or prostaglandin E2 (PGE2). Detection of the growth-restoring effects of U937 CM required that U937 CM be prepared in the presence of indomethacin or that the CM be dialyzed to remove inhibitors of U937 colony formation. Dialyzed U937 CM did not inactivate LF. Dialyzed U937 CM did not stimulate or enhance colony formation of normal human bone marrow granulocyte-macrophage (CFU-GM), erythroid (BFU-E), or multipotential (CFU-GEMM) progenitor cells, but did contain potent inhibitory activity against these progenitor cells. HL-60, EM2, EM3, and K562 cells were also evaluated. HL-60-, EM3-, and K562-CFC that were not preincubated with HuIFN gamma did not express MHC class-II antigens, and colony formation by these cells was not influenced by LF, TF, or AIF. Noninduced EM2-CFC constitutively expressed MHC class-II antigens, and colony formation by these cells was suppressed by LF, TF, and AIF. After induction of MHC class-II antigens on HL-60- and EM3-CFC by HuIFN gamma, colony formation by these cells was suppressed by LF, TF, and AIF. Colony formation by HuIFN gamma-induced EM2 cells was more responsive to inhibition by LF, TF, and AIF than was colony formation by noninduced EM2 cells. K562 cells were not induced into a responsive state to LF, TF, or AIF by HuIFN gamma. Dialyzed CM from HL-60, EM2, and EM3 cells contained activities that restored colony formation by their own LF-suppressed CFC. The activities present in dialyzed CM from U937, HL-60, EM2, and EM3 cells may be similar since they could each restore LF-suppressed colony formation of U937, HL-60, EM2, or EM3 cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Line↗

PubMed1985

Patients at risk for AIDS-related opportunistic infections. Clinical manifestations and impaired gamma interferon production.

We studied 81 men (79 homosexuals and 2 drug abusers) with persistent lymphadenopathy to determine whether those at risk for AIDS-related opportunistic infections could be identified prospectively. (Sixty-nine of 76 [91 per cent] had antibodies to human T-cell lymphotropic virus Type III [HTLV-III], and 76 of 79 [96 per cent] had abnormal T4/T8 cell ratios.) During the follow-up period (mean +/- S.E.M., 12.9 +/- 0.5 months; range, 8 to 19), infections developed in none of 38 patients with lymphadenopathy alone and in only 1 of 15 (7 per cent) with antecedent herpes zoster infection; however, 13 of 28 (46 per cent) with lymphadenopathy accompanied by constitutional symptoms or oral candidiasis or both had opportunistic infections within the follow-up period. Among the results of various T-cell assays, only antigen-stimulated lymphocyte proliferation and gamma interferon generation, which were absent or barely measurable in those in whom AIDS ultimately developed, were of prognostic value. T cells from 15 patients, 11 of whom had constitutional symptoms or thrush, failed to generate antigen-induced gamma interferon; infections developed in 10 of these 15 (67 per cent) within a mean of 8.2 months. These results suggest that patients with AIDS-related complex who are at risk for opportunistic infections within a year can be identified by correlating clinical manifestations with antigen-stimulated T-cell responses--in particular, with the production of gamma interferon.

Acquired Immunodeficiency Syndrome↗