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Biomedical subjects

H W Murray

Publications and source records attributed to H W Murray.

At least 145 records · Page 8Linked to original sources
PubMed1985

Activation of tissue macrophages from AIDS patients: in vitro response of AIDS alveolar macrophages to lymphokines and interferon-gamma.

To test the hypothesis that tissue macrophages from AIDS patients have no intrinsic defects in either antimicrobial activity or in the capacity to respond to T cell-derived activating stimuli, alveolar macrophages from 11 patients were treated with crude lymphokines produced by healthy donors. After 72 hr of pretreatment with 10% mitogen- or antigen-induced crude lymphokines (which contained 300 U/ml of interferon-gamma [IFN-gamma]), AIDS alveolar macrophages generated twofold to threefold more H2O2 and readily inhibited the replication of the intracellular pathogens Toxoplasma gondii and Chlamydia psittaci. These responses were indistinguishable from those displayed by activated alveolar cells from 12 non-AIDS patients and three healthy volunteers. As judged by the abrogating effects of a neutralizing anti-human IFN-gamma monoclonal antibody, lymphokine-induced alveolar macrophage activation appeared to be largely IFN-gamma-dependent; thus, macrophages were also stimulated with recombinant (r)IFN-gamma alone. Seventy-two hours of treatment with 300 U/ml of rIFN-gamma resulted in both enhanced oxidative and antimicrobial activity comparable to that achieved by crude lymphokines, and the responsiveness of AIDS alveolar macrophages to rIFN-gamma was identical to control cells. These in vitro results suggest that tissue mononuclear phagocytes from AIDS patients a) are free of apparent defects in intracellular antimicrobial activity, b) are fully responsive to activating T cell products, and c) support the use of IFN-gamma as a potential macrophage-activating immunotherapeutic agent in AIDS-related opportunistic infections.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Activation of human macrophages. Comparison of other cytokines with interferon-gamma.

Cytokines affecting mononuclear phagocytes were screened for activation of human macrophages to secrete H2O2 and kill toxoplasmas. In contrast to recombinant interferon-gamma (rIFN gamma), the following factors, tested in partially or highly purified form and over a wide range of concentrations, did not augment these functions: native interferon-alpha (nIFN alpha), rIFN alpha A, rIFN alpha D, rIFN beta, colony stimulating factor (type 1) (CSF-1), CSF for granulocytes and macrophages (GM-CSF), pluripotent CSF (p-CSF), tumor necrosis factor (TNF), native interleukin 2 (nIL-2), and rIL-2. Partially purified migration inhibitory factor (MIF) enhanced H2O2-releasing capacity submaximally without inducing antitoxoplasma activity, and warrants further study.

Biological Products↗
PubMed1984

Impaired production of lymphokines and immune (gamma) interferon in the acquired immunodeficiency syndrome.

To examine the cellular immune defect that predisposes patients with the acquired immunodeficiency syndrome (AIDS) to opportunistic infections, we tested T lymphocytes from 16 patients for the capacity to secrete macrophage-activating products (lymphokines) including gamma interferon. Mononuclear cells from 10 of 11 patients did not generate an effective lymphokine in response to mitogen, and 11 of 16 produced subnormal levels of gamma interferon (less than 300 U per milliliter). In addition, upon stimulation with specific microbial antigen, cells from none of 14 patients generated active lymphokines, and cells from 13 to 14 completely failed to secrete gamma interferon. However, the antimicrobial function of monocytes from the patients was intact, and once stimulated with normal lymphokines or gamma interferon alone, macrophages derived from patients' monocytes responded with enhanced and effective intracellular antimicrobial activity. These results suggest that impaired lymphokine production may predispose patients with AIDS to opportunistic infections, and they provide a rationale for using gamma interferon as immunotherapy.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Pneumocystis carinii pneumonia: a comparison between patients with the acquired immunodeficiency syndrome and patients with other immunodeficiencies.

Clinical features of 49 episodes of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome were compared with those of 39 episodes in patients with other immunosuppressive diseases. At presentation patients with the syndrome were found to have a longer median duration of symptoms (28 days versus 5 days, p = 0.0001), lower mean respiratory rate (23.4 versus 30, p = 0.005), and higher median room air arterial oxygen tension (69 mm Hg versus 52 mm Hg, p = 0.0002). The survival rate from 1979 to 1983 was similar for the two groups (57% and 50% respectively). Patients with the syndrome had a higher incidence of adverse reactions to trimethoprim-sulfamethoxazole (22 of 34 versus 2 of 17, p = 0.0007). Survivors with the syndrome at initial presentation had a significantly lower respiratory rate, and higher room air arterial oxygen tension, lymphocyte count, and serum albumin level compared to nonsurvivors. Pneumocystis carinii pneumonia presents as a more insidious disease process in patients with the syndrome, and drug therapy in these patients is complicated by frequent adverse reactions.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Reversible defect in antigen-induced lymphokine and gamma-interferon generation in cutaneous leishmaniasis.

Peripheral blood mononuclear cells from a patient with progressive Leishmania mexicana (LM) infection were examined for responses to mitogen and antigen before, during, and after successful treatment. Before therapy, his cells proliferated normally and secreted effective macrophage-activating lymphokines in response to concanavalin A (Con A) and Toxoplasma gondii antigen, but failed to show any response to LM antigen. At this time, suppressive humoral factors were not present, the intracellular antimicrobial activity of the patient's monocytes was intact, and once stimulated with normal lymphokines, his monocyte-derived macrophages readily killed his own infecting LM strain. One month after initial treatment, the patient's T cells showed variable but measurable responses to LM antigen, and by 6 mo, these responses were fully developed in proliferative and lymphokine-generating assays. The patient's lymphokines were examined for gamma-interferon (IFN-gamma) because a) a monoclonal anti-human IFN-gamma antibody abolished the capacity of lymphokines to activate normal macrophages to kill LM, and b) partially purified and recombinant IFN-gamma alone could induce macrophage leishmanicidal activity. The patient's pretreatment Con A- and T. gondii antigen-stimulated lymphocyte supernatants (which activated macrophages to kill LM) contained 2000 to 3000 U/ml of IFN-gamma, whereas his LM antigen lymphokine was devoid of activity (less than 10 U/ml). At 1 and 6 mo after therapy, however, the latter lymphokine showed 20 and 600 U/ml of IFN-gamma, respectively, paralleling the development of antigen-specific proliferation and active lymphokine generation and the clinical status of his infection. These results appear to support previous suggestions that the ability of T cells to secrete antigen-induced macrophage-activating lymphokines (particularly IFN-gamma) is a key cellular immune response to intracellular Leishmania infections.

Antibody Formation↗
PubMed1983

Identification of interferon-gamma as the lymphokine that activates human macrophage oxidative metabolism and antimicrobial activity.

Human blood mononuclear leukocytes stimulated with toxoplasma antigen, concanavalin A, mezerein plus lentil lectin, or staphylococcal enterotoxin A secreted a factor (macrophage-activating factor, or MAF) that enhanced the capacity of human macrophages to release H2O2 and to kill toxoplasmas. The same lymphoid supernatants contained IFN gamma but not IFN alpha or IFN beta. The MAF activity of six of seven unfractionated supernatants was completely eliminated by a monoclonal antibody that neutralizes IFN gamma, and MAF in the remaining supernatant was almost completely neutralized. Native IFN gamma partially purified by two independent protocols to specific activities of 1 X 10(6) and 10(7) U/mg protein was enriched in MAF activity at least as much as in antiviral activity. The capacity of macrophages to secrete H2O2 after incubation in partially purified native IFN gamma (mean peak stimulation, 8.8-fold) was greater than with unpurified lymphokines (3.8-fold) and sometimes equaled or exceeded the capacity of freshly harvested monocytes. The MAF activity of the partially purified native IFN gamma preparations was abolished by monoclonal anti-IFN gamma. Finally, IFN gamma of greater than 99% estimated purity was isolated (at Genentech, Inc.) from bacteria transformed with the cloned human gene for this lymphokine. Recombinant IFN gamma had potent MAF activity, stimulating the peroxide-releasing capacity of macrophages an average of 19.8-fold at peak response and enhancing their ability to kill toxoplasmas from 2.6 +/- 1.3% for untreated cells to 54 +/- 0.4% for treated cells. Attainment of 50% of the maximal elevation in peroxide-releasing capacity required a geometric mean concentration of 0.1 antiviral U/ml of recombinant IFN gamma, which is estimated to be approximately 6 picomolar for this preparation. Peroxide secretory capacity and toxoplasmacidal activity of macrophages peaked 2-4 d after exposure to IFN gamma. Peroxide-secretory capacity remained elevated during at least 6 d of continuous exposure, but the effect of IFN gamma was reversed within about 3 d of its removal. Activation was usually but not invariably accompanied by characteristic changes in cell morphology. Thus, IFN gamma activates human macrophage oxidative metabolism and antimicrobial activity, and appeared to be the only factor consistently capable of doing so in the diverse LK preparations tested.

Adult↗
PubMed1983

Lymphokine enhances oxygen-independent activity against intracellular pathogens.

To determine if mechanisms other than the generation of toxic oxygen intermediates are active against intracellular pathogens, oxidatively deficient mouse L cells and monocyte-derived macrophages from patients with chronic granulomatous disease were stimulated with soluble lymphocyte products. Despite no enhancement in oxidative activity, these cells displayed effective microbistatic activity against both T. gondii and C. psittaci. These results suggest a potential role for nonoxidative mechanisms in the mononuclear phagocyte's activity against intracellular pathogens, and indicate that lymphokines can regulate both oxygen-dependent and oxygen-independent antimicrobial responses.

Animals↗
PubMed1983

Killing of intracellular Leishmania donovani by human mononuclear phagocytes. Evidence for oxygen-dependent and -independent leishmanicidal activity.

Human peripheral blood monocytes were cultivated for 1-30 d before assay for H2O2 release or challenge with Leishmania donovani promastigotes (LDP) or amastigotes (LDA). 1-d cells readily generated H2O2 in response to both phorbol myristate acetate triggering (1,013 +/- 58 nmol/mg protein . 90 min) and LDP ingestion, and killed 50% of LDP within 6 h, and 90% by 24 h. In contrast, the same cells released little H2O2 during LDA ingestion, killed no LDA at 6 h and less than 30% by 24 h, and supported intracellular LDA replication. Monocyte-derived macrophages (cells first cultivated for greater than or equal to 7 d) generated less than 125 nmol H2O2/mg . 90 min after phorbol myristate acetate triggering, killed neither LDP nor LDA, and permitted both forms to replicate. The addition of mitogen- or antigen-stimulated lymphokines, however, prevented the decline in monocyte oxidative capacity, enhanced macrophage H2O2 release by more than sixfold, and, in parallel, induced 1-d monocytes to kill LDA and cultivated macrophages to display both promastigocidal and amastigocidal activity. In comparison to 1-d monocytes and lymphokine-activated macrophages from normal donors, the same cells from patients with chronic granulomatous disease (CGD) or normal cells whose oxidative activity had been impaired by catalase pretreatment or glucose deprivation exerted considerably less or no antileishmanial activity during the early (6-24 h) postphagocytic period. By 48 h after infection, however, 1-d CGD monocytes and oxidatively impaired normal cells killed 40 and greater than 80% of LDP, respectively. Although a longer period of lymphokine stimulation was required and the resulting antileishmanial effects were not as rapid as with normal cells, activated CGD monocytes and macrophages also eventually achieved promastigocidal and amastigostatic activity. These results indicate that human mononuclear phagocytes utilize both oxygen-dependent and -independent mechanisms to achieve activity against ingested Leishmania, and also demonstrate (a) the differential susceptibilities of the two forms of L. donovani to intracellular killing, (b) the key role of oxygen intermediates in effective mononuclear phagocyte antimicrobial activity, (c) the capacity of lymphocyte products to enhance oxygen-dependent as well as -independent pathways, and (d) the vulnerability of the monocyte-derived macrophage to Leishmania infection in the absence of lymphokine stimulation.

Granulomatous Disease, Chronic↗
PubMed1983

Killing of intracellular Leishmania donovani by lymphokine-stimulated human mononuclear phagocytes. Evidence that interferon-gamma is the activating lymphokine.

We have found that the crude lymphokines, which prime the human monocyte-derived macrophage to generate H2O2 and exert microbicidal activity against intracellular Leishmania donovani, are rich in interferon (IFN)-gamma (600-3,000 U/ml). To determine the role of this specific lymphocyte product in macrophage activation, lymphokines were pretreated with a monoclonal antibody that neutralizes human IFN-gamma. Antibody exposure completely abolished the capacity of both mitogen- and antigen-stimulated lymphokines to either enhance macrophage H2O2 release or induce leishmanicidal activity. In addition, partially purified and pure recombinant human IFN-gamma were as effective as crude lymphokines in activating macrophages, and 3 d of treatment with 300 U/ml resulted in a seven- to eightfold increase in H2O2 generation and the intracellular killing of both L. donovani promastigotes and amastigotes. The ability of crude lymphokines to induce monocytes and macrophages from a patient with chronic granulomatous disease to kill L. donovani promastigotes was similarly abrogated by anti-IFN-gamma antibody, and could also be achieved by IFN-gamma alone. These results suggest that IFN-gamma is the key macrophage-activating molecule present within human lymphokines, and indicate that IFN-gamma can enhance both the oxygen-dependent and -independent antiprotozoal mechanisms of human mononuclear phagocytes.

Antibodies↗
PubMed1983

Gamma-interferon is the factor in lymphokine that activates human macrophages to inhibit intracellular Chlamydia psittaci replication.

We have demonstrated previously that mitogen-induced lymphokines activate human monocyte-derived macrophages to inhibit the intracellular replication of Chlamydia psittaci. To identify the factor(s) in crude lymphokines responsible for this antimicrobial effect, we tested human Con A-induced lymphokines for interferon activity. We also attempted to neutralize the lymphokines with a monoclonal antibody directed against human gamma-interferon and examined the ability of partially purified human gamma-interferon to induce macrophage antichlamydial activity. The lymphokine-induced antichlamydial effect was measured by the inhibition of chlamydial inclusion formation in Giemsa-stained macrophage cultures. Our lymphokines were found to be rich in gamma-interferon; treatment of cells for 48 hr before infection with lymphokines containing 300 U/ml of interferon resulted in an 89% inhibition of chlamydial growth. This lymphokine effect was completely abolished by monoclonal antibody against human gamma-interferon, but not by antisera against human alpha- or beta-interferons. In addition, partially purified human gamma-interferon alone induced macrophages to restrict chlamydial growth by 95%. We conclude that it is the gamma-interferon present in human Con A-induced lymphokines that activates monocyte-derived macrophages to inhibit chlamydial replication.

Antibodies, Monoclonal↗
PubMed1983

Suppression of macrophage antimicrobial activity by a tumor cell product.

Medium conditioned by tumor cells (TCM) and certain nonmalignant cells contains a trypsin-sensitive factor that suppresses macrophage oxidative metabolism. Because the killing of intracellular pathogens such as Toxoplasma gondii and Leishmania donovani by macrophages is largely oxygen-dependent, we tested the effect of TCM on the antiprotozoal activity of mouse peritoneal macrophages. After 24 hr of cultivation with TCM, in vivo and in vitro activated macrophages could no longer kill toxoplasmas or inhibit their replication. In vivo administration of TCM resulted in similar impairment. The leishmanicidal activity of resident and activated macrophages, when measured 6 hr after infection, was markedly suppressed by in vitro exposure to TCM. The addition of exogenous H2O2 in the form of glucose-glucose oxidase reconstituted the capacity of TCM-exposed macrophages to kill L. donovani promastigotes as quickly as control cells. Thus, TCM appears to deactivate macrophages by the functional criteria of suppressed antitoxoplasmal and antileishmanial activity, as well as by the biochemical criterion of suppressed oxidative metabolism.

Animals↗