Regulation of human natural killer activity with autologous interferon

A study is performed of the effects of α-interferon and γ-interferon induced in 8 healthy donors and 9 patients with multiple sclerosis on thein vitro cytotoxic activity of natural killers in an autologous and allogeneic systems. The general characteristics of regulation are estimated on the basis of the results. There is found to be an inhibitor regulating the effect of interferon on natural killer activity, which is produced in parallel with interferon in response to interferon induction, the efficacy of this inhibitor being dependent on the initial natural killer activity; the inhibitor is absent in commercial interferon preparations. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 281–284, September, 1994     

Involvement of fibronectin and interacting serum components in the regulation of activity of human natural killer cells

The cytotoxic activity of natural killer cells and the intensity of conjugate formation are studiedin vitro in the natural cytotoxicity reaction against³H-uridine-labeled human erythromyeloleukotic cells K-562 in the presence of fibronectin, γ-globulin, and fibronectin/γ-globulin combination. It is demonstrated that fibronectin does not change natural cytotoxicity, γ-globulin increases the activity of human natural killer cells, and the fibronectin — γ-globulin combination increases both the intensity of conjugate formation and the cytotoxic activity of natural killer cells. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 7, pp. 54–59, July, 1994     

Regulation of human natural killer cell activity by an interferon inhibitor

Laboratory of Immunochemistry and Department of Interferons, N. F. Gamaleya Research Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 10, pp. 395–397, October, 1991.     

Involvement of natural killer cells in endogenous biological retranslation

Analysis of functional properties of natural killer cells displayed in reactions of natural cytotoxicity and noncytotoxic regulatory intercellular interactions suggests that this population of lymphocytes is involved in endogenous biological retranslation. In the immune system, retranslation is the production of regulatory immunoactive cytokines by a cell, cellular complex, or functional complex. The substances produced are identical to those affecting these structures. Various forms of endogenous biological retranslation in humans and higher animals, as well as its phylogenetic and ontogenetic manifestations (on the basis of noncytotoxic regulatory interactions of natural killer cells with cells of lymphoid or nonlymphoid nature) during evolution of the complex of immunobiological surveillance are considered. The axiomatic basis of retranslation realized through the system of natural cytotoxicity was established. Prospects for application of the methodology of endogenous biological retranslation to experimental and clinical studies of functioning of natural killer cells are considered. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 8, pp. 124–135, August, 1998     

Activity of human natural killer cells against target cells differing in sensitivity to interferon

Department of Interferons, N. F. Gameleya Research Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110. No. 10, pp. 406–409, October, 1990.     

Blast transformation of lymphocytes and the activity of natural killer cells in the presence of γ-globulinin vitro

The cytotoxic activity of natural killer cells against³H-uridine-labeled target cells (human erythromyeloleukosis cells K-562) and the intensity of spontaneous blast transformation are studiedin vitro in the presence of human serum γ-globulin. It is shown that spontaneous blast transformation is 49–51% due to the presence of aggregated γ-globulin, while the aggregate-free γ-globulin fraction does not induce this reaction. The cytotoxic activity of natural killer cellsin vitro declines in the presence of native γ-globulin, which is related to the influence of aggregated γ-globulin, the intensity of whose formation may increase upon a manyfold decrease in the γ-globulin content of the preparation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 625–630, December, 1994     

Functional activity of natural killer cells and killer T cells in mice after ovarian transplantation

Tashkent Postgraduate Medical Institute, Ministry of Health of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Lopatkin). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 9, pp. 273–275, September, 1991.     

Activity of human natural killer cells under different experimental conditions

Laboratory of Immunochemistry, N. F. Gamaleya Research Institute of Epidemiology and Microbiology, Russian Academy of Medical Sciences, Moscow. (Presented by Academician of the Russian Academy of Medical Sciences S. V. Prozorovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol 114, No. 8, pp. 187–189, August, 1992.     

Comparative study of antitumor cytostatic and natural suppressor activity of bone marrow cells

Cells remaining after removal from bone marrow population of cells aggregated by wheat rudiment agglutinin retained the capacity to inhibit the growth of P815 mastocytoma and L1210 lymphoma cellsin vitro, while their capacity to suppress concanavalin-induced lymphoblastogenesis dropped. Contrary to antiproliferative activity of bone marrow natural suppressor cells, their natural antitumor cytostatic activity did not depend on the presence of interferon-γ in the medium and was not mediated by nitric oxide. Thus, bone marrow antitumor cytostatic effectors are probably not equivalent to bone marrow natural suppresser cells by cell composition and by the mechanism of antiproliferative effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 4, pp. 437–439, April, 1998     

Opposite effects of dexamethasone on antitumor and natural suppressor activities of bone marrow cells

Effects of dexamethasone on the ability of nonadherent bone marrow cells to inhibit proliferation of mastocytoma P815 cells and concanavalin A-stimulated proliferation of syngeneic splenocytes were studied. Antitumor activity of cells increased, but their natural suppressor activity decreased in the presence of dexamethasone. Pretreatment with dexamethasone (for 3 h) did not affect the sensitivity of mastocytoma cells to antitumor factors and the antitumor activity of bone marrow effectors. Pretreatment of bone marrow cells with dexamethasone for 24 h potentiated antitumor activity of their nonadherent fractions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 459–461, April, 2000     

Subsets of human natural killer cells and their regulatory effects

Human natural killer (NK) cells have distinct functions as NK^tolerant, NK^cytotoxic and NK^regulatory cells and can be divided into different subsets based on the relative expression of the surface markers CD27 and CD11b. CD27⁺ NK cells, which are abundant cytokine producers, are numerically in the minority in human peripheral blood but constitute the large population of NK cells in cord blood, spleen, tonsil and decidua tissues. Recent data suggest that these NK cells may have immunoregulatory properties under certain conditions. In this review, we will focus on these new NK cell subsets and discuss how regulatory NK cells may serve as rheostats or sentinels in controlling inflammation and maintaining immune homeostasis in various organs.     

Dipeptidylpeptidase-4 as a surface marker of human natural killer cells

Institute of Experimental Cardiology, All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Smirnov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 10, pp. 411–413, October, 1990.     

The effect of valacyclovir treatment on natural killer cells of infertile women

PROBLEM: The aim of this study was to investigate the effect of valacyclovir treatment on natural killer (NK) cell concentration in the peripheral blood of infertile women. METHOD OF STUDY: Peripheral blood NK cell concentration of 104 non-pregnant women with a history of infertility was determined by flow cytometry. The controls were 14 fertile non-pregnant women. A cohort of 42 out of 104 women--whose NK cell levels were 175/microL or higher--was prospectively studied for the presence of HSV-1, 2, VZV, cytomegalovirus, HHV-6, HHV-7 and HHV-8 DNA in the peripheral blood and was orally administered valacyclovir (open label study). RESULTS: Herpes virus DNA was detected in 64.3% of the 42 women examined. Prior to valacyclovir treatment mean NK cell concentration in herpes-negative group was statistically higher from control group but lower from herpes positive group (P = 0.0007, ANOVA). Following valacyclovir treatment the mean NK cell concentration was statistically decreased in all studied women (P = 0.000453), in herpes-negative (P = 0.01622) and in herpes positive group (P = 0.0056). Sufficient decrease was observed in 31 (73.8%) of 42 women who received the drug. CONCLUSIONS: Valacyclovir treatment is associated with a decrease of NK cell levels in most of the women with a history of infertility.     

Ligation of CD8alpha on human natural killer cells prevents activation-induced apoptosis and enhances cytolytic activity

It has been previously shown that the subset of human natural killer (NK) cells which express CD8 in a homodimeric alpha/alpha form are more cytotoxic than their CD8- counterparts but the mechanisms behind this differential cytolytic activity remained unknown. Target cell lysis by CD8- NK cells is associated with high levels of effector cell apoptosis, which is in contrast to the significantly lower levels found in the CD8alpha+ cells after lysis of the same targets. We report that cross-linking of the CD8alpha chains on NK cells induces rapid rises in intracellular Ca2+ and increased expression of CD69 at the cell surface by initiating the influx of extracellular Ca2+ ions. We demonstrate that secretion of cytolytic enzymes initiates NK-cell apoptosis from which CD8alpha+ NK cells are protected by an influx of exogenous calcium following ligation of CD8 on the NK-cell surface. This ligation is through interaction with fellow NK cells in the cell conjugate and can occur when the target cells lack major histocompatibility complex (MHC) Class I expression. Protection from apoptosis is blocked by preincubation of the NK cells with anti-MHC Class I antibody. Thus, in contrast to the CD8- subset, CD8alpha+ NK cells are capable of sequential lysis of multiple target cells.     

Preparation of monospecific immunoglobulin against human leukocytic interferon

Donkeys were immunized regularly at 7-day intervals with human leukocytic interferon, injected subcutaneously in a dose of 1600 units in 10 ml. Interferon-neutralizing antibodies were found in a titer of 1:128–1:256 in the sera of the animals after 38–40 immunizations. As a result of continued immunizations the titer of these antibodies rose considerably. Parallel tests revealed antibodies against components of the system in which the interferon was obtained. Donkey interferon plasma was prepared by plasmaphaeresis and an anti-interferon immunoglobulin was isolated from it by precipitation with ammonium sulfate at 50% saturation. Anti-interferon immunoglobulin was freed from contaminating antibodies by affinity chromatography on a combined immunosorbent.Laboratory of Immunology of Leukemias, Central Research Institute of Hematology and Blood Transfusion, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 11, pp. 561–563, November, 1978.     

Effect of natural antiphospholipid antibodies on antithrombotic activity of vascular wall

Natural latent human antibodies cross-reacting with DNA and cardiolipin, interact with human endothelial cells, decrease antiaggregation activity of rat aortic wall, and increase fibrinolytic activity of the wall of the inferior vena cava. It is assumed that natural antiphospholipid antibodies present in immunoglobulin preparations in a latent state modify antithrombogenic activity of the vascular wall and are a potential cause of antiphospholipid syndrome. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 417–419, April, 2000     

Liaison between natural killer cells and dendritic cells in human gestation

A successful pregnancy relies on immunological adaptations that allow the fetus to grow and develop in the uterus, despite being recognized by maternal immune cells. Among several immunocompetent cell types present within the human maternal/fetal interface, DC-SIGN~ dendritic cells （DCs） and CD56＋ natural killer （NK） cells are of major importance for early pregnancy maintenance, not only generating maternal immunological tolerance but also regulating stromal cell differentiation. Previous reports show the presence of NK-DC cell conjugates in first trimester human decidua, suggesting that these cells may play a role in the modulation of the local immune response within the uterus. While effective immunity is necessary to protect the mother from harmful pathogens, some form of tolerance must be activated to avoid an immune response against fetal antigens. This review article discusses current evidence concerning the functions of DC and NK cells in pregnancy and their liaison in human decidua.