In Vitro Effects of Various Metals on Natural Killer Cell Activity in Cultured Human Lymphocytes

Heavy metals have been shown to have a differential effects on various aspects of immune response. Recently natural killer cells have been widely investigated due to their purported role in immune surveillance. To ascertain the immunotoxic effects of lead, cadmium, nickel and chromium on natural killer (NK) cell activity in vitro, peripheral blood lymphocytes from normal donors were examined in the presence of different concentrations (10^-5-10^-8 M) of four selected metal salts (cadmium sulphate, lead nitrate, chromium nitrate and nickel sulphate). NK cell activity was evaluated in a 4-h chromium release assay against K562 target cells. All of the metal salts were found to exert no effect on NK cell function in the human concentration range.     

In Vitro Effects of Various Metals on Natural Killer Cell Activity in Cultured Human Lymphocytes

Abstract

Heavy metals have been shown to have a differential effects on various aspects of immune response. Recently natural killer cells have been widely investigated due to their purported role in immune surveillance. To ascertain the immunotoxic effects of lead, cadmium, nickel and chromium on natural killer (NK) cell activity in vitro, peripheral blood lymphocytes from normal donors were examined in the presence of different concentrations (10^?5-10^?8 M) of four selected metal salts (cadmium sulphate, lead nitrate, chromium nitrate and nickel sulphate). NK cell activity was evaluated in a 4-h chromium release assay against K562 target cells. All of the metal salts were found to exert no effect on NK cell function in the human concentration range.     

The Effects of Stress on Natural Killer Cell Activity in Healthy Men1

Several studies have shown that exposure to acute laboratory stressors produces an immediate change in immune function. We examined the effects of a mild laboratory stressor on natural killer (NK) cell cytotoxicity and on psychological and cardiovascular measures in 24 adult males. Subjects in the experimental condition worked on the Stroop task without interference for 30 min with blood samples drawn at baseline, 10, 20, and 30 min into the task, and 40 min after completing the task. The 30-min stressor produced increases in self-reported stress and tension, and in SBP, DBP, and HR. It was also associated with a decrease in NK cell cytotoxicity 40 min after the stressor. Results are discussed in relation to the effects of mild and intense stressors and future research implications.     

Depressed Natural Killer Cell Activity in Schizophrenic Patients

Factors that suppress natural killer (NK) cell activity were examined in a random sample of 73 schizophrenic patients. NK activity in these patients were compared with 25 healthy age, sex and race matched controls. The mean percent of NK activity was 21% in the schizophrenic group compared with 30% percent in the controls. The difference between these two groups was statistically significant. The mean percent of NK activity in the chronic undifferentiated schizophrenic subgroup and schizoaffective subgroup were 20% and 22% respectively. The degree of suppression of NK activity in the chronic undifferentiated subgroup was higher than in the schizoaffective one, but the difference was not statistically significant. The two subgroups were comparable regarding other immune related variables such as total white cell count, neutrophils, lymphocytes, total protein, albumin, globulin, immunoglobulins and stress. The lower impairment of NK activity in the schizoaffective subgroup may be due to their exposure to lithium which can enhance immune functions. Factors associated with significant suppression of NK activity in schizophrenic patients were physical restraint, number of psychotropic medications, number of chronic non-psychiatric diagnoses and race. Psychosocial stressors were associated with suppression of NK activity but it was not statistically significant. Our results identify factors associated with reduced NK activity observed in certain schizophrenic patients and NK activity in these patients may be the result of interaction between various factors.     

Depressed Natural Killer Cell Activity in Schizophrenic Patients

Factors that suppress natural killer (NK) cell activity were examined in a random sample of 73 schizophrenic patients. NK activity in these patients were compared with 25 healthy age, sex and race matched controls. The mean percent of NK activity was 21% in the schizophrenic group compared with 30% percent in the controls. The difference between these two groups was statistically significant. The mean percent of NK activity in the chronic undifferentiated schizophrenic subgroup and schizoaffective subgroup were 20% and 22% respectively. The degree of suppression of NK activity in the chronic undifferentiated subgroup was higher than in the schizoaffective one, but the difference was not statistically significant. The two subgroups were comparable regarding other immune related variables such as total white cell count, neutrophils, lymphocytes, total protein, albumin, globulin, immunoglobulins and stress. The lower impairment of NK activity in the schizoaffective subgroup may be due to their exposure to lithium which can enhance immune functions. Factors associated with significant suppression of NK activity in schizophrenic patients were physical restraint, number of psychotropic medications, number of chronic non-psychiatric diagnoses and race. Psychosocial stressors were associated with suppression of NK activity but it was not statistically significant. Our results identify factors associated with reduced NK activity observed in certain schizophrenic patients and NK activity in these patients may be the result of interaction between various factors.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. II. Increased Sensitivity to Natural Killer Cytotoxic Factor (NKCF)

Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. II. Increased Sensitivity to Natural Killer Cytotoxic Factor (NKCF)

Abstract

Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.     

Reduced Natural Killer Cell Activity of Lymphocytes from Patients with Werner''s Syndrome and Recovery of Its Activity by Purified Human Leucocyte Interferon

Natural killing (NK) activities were measured in peripheral blood lymphocytes (PBL) from 14 patients with Werner's syndrome (WS), and the results were compared with those of 187 normal individuals at different ages. The NK activities of healthy donors were demonstrated a characteristic and invariable manner in accordance with the age and the sex, whereas the activities of WS patients were considerably reduced irrespective of the age and the sex. When normal PBL were preincubated with WS sera containing anti-lymphocyte antibodies (ALA) plus rabbit complement, the NK activities of the surviving PBL were markedly reduced when compared with those of PBL treated with other heterologous ALA of rabbit origin in the same manner. PBL from WS patients treated with purified human leucocyte interferon augmented the NK activity even beyond the range of controls. These results suggested that NK activities in WS patients were reduced in a manner similar to that in normal old individuals. The ALA reactive to NK cells in WS patients may participate in the reduction of NK activities. The augmentative effect of interferon on NK activities in WS patients may also suggest the possible blocking of potent NK activities by an unknown mechanism rather than an intrinsic defect of their NK cells.     

Effects of Serum from Pregnant Versus Nonpregnant Women on Natural Killer Cell Activity

PROBLEM: To test the effect of serum obtained from in vitro fertilization-embryo transfer (IVF-ET) patients on the healthy volunteers natural killer (NK) cell activity. METHOD OF STUDY: Retrospective non-randomized clinical study. Suppressive effect on NK cell activity was measured with serum obtained from 25 pregnant and 24 non-pregnant women during IVF-ET procedure. RESULTS: Suppressive serum effect of volunteers' NK cell activity was significantly higher in pregnant than in non-pregnant women (P < 0.01). CONCLUSIONS: The suppressive activity of serum from pregnant women on NK cell suppression activity was useful in predicting the establishment of a successful pregnancy.     

某些肝病患者外周血单个核细胞天然杀伤(NK)活性的探讨

目前认为,NK细胞可能参与构成机体抗肿瘤生长和病毒感染的第一道防线。对许多恶性肿瘤患者的研究表明,其外周血NK活性低下,且与肿瘤进展和转移有关。但对病毒感染患者NK活性变化研究尚少,结果也不一致。一般认为,乙型病毒性肝炎和肝硬化(LC)可演变成肝细胞性肝癌(HCC)     

Phytoncides (Wood Essential Oils) Induce Human Natural Killer Cell Activity

To explore the effect of forest bathing on the human immune system, we investigated the effect of phytoncides (wood essential oils) on natural killer (NK) activity and the expression of perforin, granzyme A and granulysin in human NK cells. We used NK-92MI cell, an interleukin-2 independent human NK cell line derived from the NK-92 cell, in the present study. NK-92MI cells express the CD56 surface marker, perforin, granzyme A, and granulysin by flow cytometry and are highly cytotoxic to K562 cells in chromium release assay. Phytoncides significantly increase cytolytic activity of NK-92MI cells in a dose-dependent manner and significantly increase the expression of perforin, granzyme A, and granulysin in the NK-92MI cells. Phytoncides also partially, but significantly, restore the decreased human NK activity and the decreased perforin, granzyme A, and granulysin expression in NK-92MI cells induced by dimethyl 2,2-dichlorovinyl phosphate (DDVP), an organophosphorus pesticide. Pretreatment with phytoncides partially prevents DDVP-induced inhibition of NK activity. Taken together, these data indicate that phytoncides significantly enhance human NK activity and this effect is at least partially mediated by induction of intracellular perforin, granzyme A, and granulysin.     

应激对小鼠T、B细胞分裂原反应性及天然杀伤细胞活性的影响

自Jerne提出免疫网络学说,对免疫调节的研究日益深入。但这些工作多限于研究免疫系统内部的相互作用,而忽略了免疫系统外的因素对免疫应答的影响。近年来有些作者注意到神经-内分泌系统对免疫反应的调控作用,应激的研究应为其中之一。应激往往引起神经-内分泌系统的一系列变化,并导致免疫功能的改变。手术、创伤、疼痛引起的应激反应,往往造成患者的抗感染、抗肿瘤的能力下降,认为与应激介导的免疫抑制效应有关。但未见有关手术应激的动物实验报告。本文重点研究了手术应激动物模型的建立,证明此种应激可明显抑制小鼠的分裂原反应性及NK活性。比较不同分裂原反应性受抑的动力变化,发现不同分裂原反应性对手术应激的抑制效应的敏感性不     

Production and Characterization of a Novel Monoclonal Antibody Inhibitory for Murine Natural Killer Cell Activity

Natural killer (NK) cells are considered to play an important role in tumor surveillance. The killing of tumor target cells by NK cells is the result of a complex series of sequential binding, signal processing and lytic events. However, the mechanism which NK cells use to recognize tumor targets is poorly understood. To further study the cell-surface molecules involved in tumor recognition, we immunized rats against cloned murine T cells with NK activity (DBA/2.1) and generated rat-mouse hybridomas which were screened for the ability to block lytic activity of DBA/2.1 effector cells. Culture supernatants from one IgM-producing hybridoma, designated S1C4, were found to consistently inhibit DBA/2.1-mediated lysis of YAC-1 target cells. Endogenous splenic NK activity was also diminished in the presence of S1C4 monoclonal antibody (mAb) while alloantigen-specific cytotoxic T lymphocyte (CTL) activity was not affected. S1C4 mAb appears to react with effector cell-surface structures involved in the recognition/adhesion phase of NK activity since pretreatment of effector cells with mAb S1C4 inhibits their ability to bind to YAC-1 target cells. ELISA studies revealed that the S1C4 antigen is expressed by a range of lymphoid cell lines, as well as by DBA/2.1 cells and fresh splenic NK cells. S1C4 mAb were shown to react with 22, 24, 30, and 46 kiloDalton (kDa) DBA/2.1 cell membrane components on immunoblots performed under reducing conditions. These structures do not correspond to any known recognition/adhesion molecules, suggesting that mAb S1C4 defines novel cell membrane components involved in NK cell function.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. L Elevation of Sensitivity of Tumor Cells and Lytic Function of NK Cells

The in vitro effect of X-ray irradiation on the human natural killer (NK) system was studied. When K562 cells were irradiated with X-rays and cultured for 18 hours, they showed increased sensitivity to lysis by blood lymphocytes and purified large granular lymphocytes (LGL). The X-ray-induced augmentation was observed as little as 2 Gy irradiation, reaching maximum at 5 to 20 Gy. The doses of X-rays did not influence the viability and spontaneous release of the target cells. On the other hand, irradiation with X-rays of NK cells at 5 to 15 Gy resulted in a transient increase in NK activity at 1 hour, and then the activity declined and was completely lost after 24 hours. However, when LGL were cultured with interferon immediately after irradiation, they maintained elevated NK activity. These results suggest the possible use of low doses of X-ray irradiation in combination with biological response modifiers for treatment of cancer.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. L Elevation of Sensitivity of Tumor Cells and Lytic Function of NK Cells

Abstract

The in vitro effect of X-ray irradiation on the human natural killer (NK) system was studied. When K562 cells were irradiated with X-rays and cultured for 18 hours, they showed increased sensitivity to lysis by blood lymphocytes and purified large granular lymphocytes (LGL). The X-ray-induced augmentation was observed as little as 2 Gy irradiation, reaching maximum at 5 to 20 Gy. The doses of X-rays did not influence the viability and spontaneous release of the target cells. On the other hand, irradiation with X-rays of NK cells at 5 to 15 Gy resulted in a transient increase in NK activity at 1 hour, and then the activity declined and was completely lost after 24 hours. However, when LGL were cultured with interferon immediately after irradiation, they maintained elevated NK activity. These results suggest the possible use of low doses of X-ray irradiation in combination with biological response modifiers for treatment of cancer.     

Inhibition of Human Natural Killer Cell Activity by Platelet-Derived Growth Factor (PDGF)

We have previously reported that platelet-derived growth factor (PDGF) substantially inhibits human natural killer (NK) cell cytotoxicity, and that NK cells possess high-affinity surface binding sites for the PDGF-AB isoform. In this communication, we present direct evidence for the presence of A-type (alpha) PDGF receptors on human NK cells by demonstrating that human NK cells have approximately 150,000 high-affinity, surface binding sites for recombinant (r)PDGF-AA and approximately 300,000 high-affinity, surface binding sites for rPDGF-BB. This was determined by the competitive binding of 125I-labelled rPDGF-AA or 125I-labelled rPDGF-BB and homologous unlabelled rPDGF-AA or rPDGF-BB to FACS-sorted, CD16+ lymphoid (NK) cells, and Scatchard analysis of these data. In addition, we also demonstrate that the various isoforms of PDGF have differential effects on NK-cell cytotoxicity. Physiological quantities (100 ng/ml) of rPDGF-BB homodimers, highly purified PDGF-AB heterodimers from outdated platelets, and rPDGF-AB heterodimers substantially inhibited NK-cell cytotoxicity in both a dose- and time-dependent manner. In contrast, pretreatment of NK cells with equivalent nanogram amounts of rPDGF-AA homodimers resulted in a significantly weaker inhibitory effect on NK-cell cytotoxicity as compared with the PDGF-BB and PDGF-AB isoforms. The implications of these findings are discussed.     

Induction of Natural Killer Cell Activity and Allocytotoxicity in Human Peripheral Blood Lymphocytes after Mixed Lymphocyte Culture

The K-562 tumour cell is a highly susceptible target for natural killer (NK) cell lysis by lymphocytes of human peripheral blood. We have studied the antigenic relationship between the recognition sites for lysis of lymphoid and various tumour target cells by cytolytic T lymphocytes (CTL) and NK cells induced in mixed lymphocyte cultures (MLC). The characteristics of these two effector cell types have also been investigated. It was demonstrated that fresh NK cells lose their NK lytic activity when cultured alone. Cell lines not susceptible to lysis by fresh NK cells are lysed by MLC-induced NK cells. There is no antigenic relationship between the recognition sites for the alloreactive T lymphocytes and MLC-generated NK cells expressed on the lymphoid target cells and the tumour target cells, respectively. The MLC-generated alloreactive T cells and NK cells are not identical. The MLC-generated NK cells are different from the fresh NK cells present in the peripheral blood.     

Multiplication of Herpes Simplex Virus in Large Granular Lymphocytes that Co-Fractionate with Human Natural Killer Cell Activity

Highly enriched preparations of human large granular lymphocytes (LGL) cells, isolated from peripheral blood of normal adult donors, showed partial intrinsic resistance to infection with herpes simplex virus type 1 (HSV-1). Three subsets of LGL cells were identified on the basis of susceptibility to this virus: 1) resistant cells: 2) abortively infected cells; and 3) permissive cells. An average of 25% of LGL cells were completely resistant to infection. The majority (approximately 75%) could be infected as estimated by immunofluorescence. Only 5% of the original cell suspensions were productively infected as determined by infections center assay and transmission electron microscopy. These results have been reproduced in multiple experiments from 8 different donors consisting of both males and females. No significant difference in LGL cell responses to HSV-1 were detected within this population. Enriched LGL preparations exhibited enhanced natural killer (NK) cell activity. These findings raise several questions concerning the biological significance of LGL susceptibility to infection with HSV-1, relative to virus transport and/or immune surveillance by NK cells.     

Multiplication of Herpes Simplex Virus in Large Granular Lymphocytes that Co-Fractionate with Human Natural Killer Cell Activity

Highly enriched preparations of human large granular lymphocytes (LGL) cells, isolated from peripheral blood of normal adult donors, showed partial intrinsic resistance to infection with herpes simplex virus type 1 (HSV-1). Three subsets of LGL cells were identified on the basis of susceptibility to this virus: 1) resistant cells: 2) abortively infected cells; and 3) permissive cells. An average of 25% of LGL cells were completely resistant to infection. The majority (approximately 75%) could be infected as estimated by immunofluorescence. Only 5% of the original cell suspensions were productively infected as determined by infections center assay and transmission electron microscopy. These results have been reproduced in multiple experiments from 8 different donors consisting of both males and females. No significant difference in LGL cell responses to HSV-1 were detected within this population. Enriched LGL preparations exhibited enhanced natural killer (NK) cell activity. These findings raise several questions concerning the biological significance of LGL susceptibility to infection with HSV-1, relative to virus transport and/or immune surveillance by NK cells.     

Effects of Chloroquine, Mefloquine and Quinine on Natural Killer Cell Activity in vitro

Natural killer (NK) cell activity against K 562 target cells was inhibited by pharmacological concentrations of chloroquine, mefloquine and quinine. The most potent were mefloquine and quinine. The drug-induced inhibition of the NK cell activity was abolished by addition of alpha-interferon (IF) or interleukin 2 (Il-2); preincubation of mononuclear cells with IF or Il-2 followed by addition of anti-malarial drugs decreased the inhibitory effects of the drugs. The drug-induced inhibition of the NK cell activity was not dependent on the presence of monocytes. Using monocyte depleted Percoll fractionated NK cell enriched populations in a single cell agarose assay, it was shown that the inhibitory effects of mefloquine, but not of chloroquine and quinine were due to an inhibition of the formation of effector/target cell conjugates.