Coinduction of granulocyte-macrophage colony-stimulating factor release and lymphokine-activated killer cell susceptibility in monocytes by interleukin-2 via interleukin-2 receptor beta

Human monocytes express interleukin-2 receptor beta (IL-2R beta) constitutively; however, the function of these receptors has not been fully delineated. We discovered that IL-2R beta directs two biologic activities in human monocytes, the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and increased susceptibility to lysis by lymphokine-activated killer cells (LAK) cells. Human monocytes were purified from peripheral blood mononuclear cells by plastic adherence and anti-CD2 plus complement lysis. By a 5-hour 51Cr-release assay, monocytes cultured in IL-2 were found to gain increasing susceptibility to LAK cells with time and this effect was dose dependent. Maximal susceptibility was obtained with a 4-day culture in 1,000 U/mL of IL-2. Monocytes were also found to release GM-CSF in response to IL-2 using a CSF-dependent cell line, Mo7e. Because IL-2-induced GM-CSF release coincides with LAK lysis of IL-2-cultured monocytes, we treated monocytes with anti-GM-CSF and anti-IL-2R beta to determine whether GM-CSF release and LAK susceptibility were dependent or independent events. We found that both phenomena were inhibited by either antibody. Therefore, we conclude that IL-2-induced release of GM-CSF is mediated by IL-2R beta, which then acts to modulate the susceptibility of monocytes to lysis by LAK cells.

Retinol release by activated rat hepatic lipocytes: regulation by Kupffer cell-conditioned medium and PDGF

In normal liver, lipocytes are the principal reservoir for retinoids, which are stored as retinyl esters. In liver injury, lipocytes activate into myofibroblast-like cells, which lack retinoid. We examined mechanisms of retinoid loss using a culture model in which lipocyte activation is provoked by exposure to Kupffer cell-conditioned medium (KCM) (S.L. Friedman and M. J. P. Arthur, J. Clin. Invest. 84: 1780-1785, 1989). In lipocytes exposed to KCM, there was approximately 11-fold more retinol in medium than in untreated cells, without release of retinyl esters. Both bile salt-dependent and -independent retinyl ester hydrolase was entirely intracellular, suggesting that the increase in retinol was due to intracellular hydrolysis; activity of bile salt-independent hydrolase was increased in KCM-treated lipocytes. Release of retinol was serum dependent and inhibited 40% by antibodies to platelet-derived growth factor (PDGF). The addition of 10 nM PDGF to serum-free KCM also induced retinol release. Lipocyte expression of mRNAs for cellular retinol-binding protein, retinoic acid receptor (RAR)-alpha, and RAR-beta was unchanged after exposure to KCM. In summary, activation of cultured lipocytes by KCM is accompanied by serum- and PDGF-dependent release of retinol; a similar mechanism may underlie retinoid loss by activated lipocytes in vivo.

Organization of human T-cell receptor beta-chain genes: clusters of V beta genes are present on chromosomes 7 and 9

To ascertain the extent and organization of the germ-line human T-cell receptor (TCR) beta-chain gene repertoire, beta-chain variable region (V beta) genes were mapped by pulsed-field gel electrophoresis, cosmid cloning, and in situ hybridization. Probes derived from the 24 known V beta families were mapped to a total of six Sfi I fragments in DNA samples from multiple individuals representing all possible haplotypes of TCR V- and C (constant)-region insertion/deletion-related polymorphisms. Four of the Sfi I fragments were linked to one another to develop an extended map of the TCR beta-chain gene complex previously localized to chromosome 7q35. The remaining two Sfi I fragments, containing 6 V beta genes, could not be linked to the TCR beta-chain gene complex. Using human-hamster somatic cell hybrids and in situ hybridization, these orphon genes were localized to chromosome 9p. Nucleotide sequences of the orphon V beta genes, derived from cosmid clones, were 93-97% identical to V beta genes in the TCR beta-chain gene complex. Open reading frames in three of the orphon V beta genes were intact as were the recombination signal sequences. As expected, based on their orphon status, none of the V beta genes of chromosome 9 was detected in transcripts containing C beta. These results indicate that the functional germ-line V beta repertoire in humans is substantially (10%) smaller than previously estimated.

Activation of tumor necrosis factor-alpha production from human neutrophils by IL-2 via IL-2-R beta

In addition to T cells, NK cells, B cells, and monocytes, we provide new evidence that human polymorphonuclear neutrophils (PMN) can be functionally activated by IL-2 via binding to IL-2R beta expressed on the cell surface. Brief exposure of normal PMN to human rIL-2 enhanced both transcriptional and translational expression of TNF-alpha. The release of TNF-alpha protein by IL-2-treated PMN was inhibitable by a specific mAb against human IL-2-R beta. The response to IL-2 was dose and time dependent with the increase in TNF-alpha mRNA detected maximally 3 h after IL-2 exposure, followed by a continuous maintenance of high mRNA levels up to 18 h. The TNF-alpha mRNA was significantly increased above the medium control level, with as little as 10 U/ml of IL-2. Maximal transcription was obtained with 1000 U/ml of IL-2, which achieved the level observed with known neutrophil activating factors such as granulocyte-macrophage-CSF, IL-8, and Candida albicans. Using actinomycin D, it was found that new and continuous synthesis of a labile TNF-alpha mRNA was responsible for the observed high levels of transcripts. Of significance was the observation that cycloheximide could selectively modulate TNF-alpha mRNA transcription in neutrophils, depending on the cytokine used. Cycloheximide did not affect or alter TNF-alpha mRNA induction in IL-2-treated neutrophils but abrogated it in granulocyte-macrophage-CSF-treated neutrophils and superinduced transcription in C. albicans-treated neutrophils. Thus various control elements must be involved in the transcription of the TNF-alpha genes that are responsive to different cytokines and activating factors. The induction of TNF-alpha and functional activation of neutrophils by IL-2 is therefore an important immunomodulatory property of IL-2 that has not heretofore been recognized.

Activation of tumor necrosis factor-alpha production from human neutrophils by IL-2 via IL-2-R beta

In addition to T cells, NK cells, B cells, and monocytes, we provide new evidence that human polymorphonuclear neutrophils (PMN) can be functionally activated by IL-2 via binding to IL-2R beta expressed on the cell surface. Brief exposure of normal PMN to human rIL-2 enhanced both transcriptional and translational expression of TNF-alpha. The release of TNF-alpha protein by IL-2-treated PMN was inhibitable by a specific mAb against human IL-2-R beta. The response to IL-2 was dose and time dependent with the increase in TNF-alpha mRNA detected maximally 3 h after IL-2 exposure, followed by a continuous maintenance of high mRNA levels up to 18 h. The TNF-alpha mRNA was significantly increased above the medium control level, with as little as 10 U/ml of IL-2. Maximal transcription was obtained with 1000 U/ml of IL-2, which achieved the level observed with known neutrophil activating factors such as granulocyte-macrophage-CSF, IL-8, and Candida albicans. Using actinomycin D, it was found that new and continuous synthesis of a labile TNF-alpha mRNA was responsible for the observed high levels of transcripts. Of significance was the observation that cycloheximide could selectively modulate TNF-alpha mRNA transcription in neutrophils, depending on the cytokine used. Cycloheximide did not affect or alter TNF-alpha mRNA induction in IL-2-treated neutrophils but abrogated it in granulocyte-macrophage-CSF-treated neutrophils and superinduced transcription in C. albicans-treated neutrophils. Thus various control elements must be involved in the transcription of the TNF-alpha genes that are responsive to different cytokines and activating factors. The induction of TNF-alpha and functional activation of neutrophils by IL-2 is therefore an important immunomodulatory property of IL-2 that has not heretofore been recognized.

Effects of L-type calcium channel antagonists on the serotonin-depleting actions of MDMA in rats

The calcium channel antagonists verapamil nifedipine and flunarizine all increased the threshold for convulsions induced by N-methyl-D-aspartate in rats. By contrast, only flunarizine blocked the long-term serotonin-depleting effects of 3,4-methylenedioxymethamphetamine. Flunarizine was also the only drug that antagonized methamphetamine-induced stereotypy. These findings suggest that calcium influx through L-type channels does not participate in the neurotoxic mechanism of MDMA, and that the neuroprotective actions of flunarizine are probably related to its anti-dopaminergic activity.

Function associated with IL-2 receptor-beta on human neutrophils. Mechanism of activation of antifungal activity against Candida albicans by IL-2

Polymorphonuclear neutrophils (PMN) are essential components of the host defense system against a wide variety of pathogens. We report here the novel finding that freshly isolated human PMN constitutively express detectable surface levels of IL-2R beta, but not IL-2R alpha, as analyzed by flow cytometry. Northern blot analysis confirmed the constitutive expression of mRNA for IL-2R beta in PMN. Scatchard analysis using 125I-labeled IL-2 demonstrated the presence of approximately 600 intermediate binding IL-2R per PMN, with a dissociation constant of 1.1 x 10(-9) M, similar to that of IL-2 binding to YT-1 tumor cells that specifically express IL-2R beta. More importantly, PMN were able to respond functionally to IL-2 by enhanced growth-inhibitory activity against an opportunistic fungal pathogen, Candida albicans. IL-2 activation of antifungal activity was dose-dependent, with some functional activation detected at 1 U/ml of rIL-2 and maximal activation at 1000 U/ml. The action of IL-2 was rapid, with maximal PMN activation after 30-min incubation with IL-2. The IL-2 enhancement of antifungal activity could be blocked by a specific antibody against IL-2R beta, but not by anti-IL-2R alpha. Analysis of the mechanism of IL-2 activation of PMN indicated that oxidative metabolism, as measured by superoxide anion production, was not involved. Instead, PMN release of lactoferrin appeared to be responsible for the heightened activity against C. albicans in IL-2-treated PMN. Not only was lactoferrin detected in the supernatants of IL-2-treated PMN, but also the antifungal activity of PMN activated by IL-2 could be blocked in the presence of antilactoferrin. These results, taken together, indicate that normal PMN are capable of functionally responding to IL-2 via expression of the IL-2R beta chain.

Function associated with IL-2 receptor-beta on human neutrophils. Mechanism of activation of antifungal activity against Candida albicans by IL-2

Polymorphonuclear neutrophils (PMN) are essential components of the host defense system against a wide variety of pathogens. We report here the novel finding that freshly isolated human PMN constitutively express detectable surface levels of IL-2R beta, but not IL-2R alpha, as analyzed by flow cytometry. Northern blot analysis confirmed the constitutive expression of mRNA for IL-2R beta in PMN. Scatchard analysis using 125I-labeled IL-2 demonstrated the presence of approximately 600 intermediate binding IL-2R per PMN, with a dissociation constant of 1.1 x 10(-9) M, similar to that of IL-2 binding to YT-1 tumor cells that specifically express IL-2R beta. More importantly, PMN were able to respond functionally to IL-2 by enhanced growth-inhibitory activity against an opportunistic fungal pathogen, Candida albicans. IL-2 activation of antifungal activity was dose-dependent, with some functional activation detected at 1 U/ml of rIL-2 and maximal activation at 1000 U/ml. The action of IL-2 was rapid, with maximal PMN activation after 30-min incubation with IL-2. The IL-2 enhancement of antifungal activity could be blocked by a specific antibody against IL-2R beta, but not by anti-IL-2R alpha. Analysis of the mechanism of IL-2 activation of PMN indicated that oxidative metabolism, as measured by superoxide anion production, was not involved. Instead, PMN release of lactoferrin appeared to be responsible for the heightened activity against C. albicans in IL-2-treated PMN. Not only was lactoferrin detected in the supernatants of IL-2-treated PMN, but also the antifungal activity of PMN activated by IL-2 could be blocked in the presence of antilactoferrin. These results, taken together, indicate that normal PMN are capable of functionally responding to IL-2 via expression of the IL-2R beta chain.

Impaired polymorphonuclear leukocyte anticandidal function in injured adults with elevated Candida antigen titers

Per protocol, adults with an Injury Severity Score of 18 or greater underwent Candida antigen titer measurements weekly. If titers were 1:4 or greater, neutrophil function against Candida albicans was determined with use of a tritiated glucose incorporation assay, and polymorphonuclear leukocytes obtained from healthy blood donors were studied concurrently for comparison. Polymorphonuclear leukocytes from healthy blood donors and injured patients with elevated titers were able to inhibit C albicans growth in a dose-dependent fashion. Polymorphonuclear leukocytes from injured patients with elevated titers had a significantly depressed ability to inhibit Calbicans growth compared with those from healthy blood donors at all effector cell-to-target cell ratios tested. Cytokine-treated polymorphonuclear leukocytes from healthy blood donors and injured patients with elevated Candida antigen titers demonstrated significantly improved anticandidal activity at all ratios of polymorphonuclear leukocytes-to-Candida. Granulocyte macrophage-colony stimulating factor was the most potent cytokine at reconstituting polymorphonuclear leukocyte function, followed by interferon gamma and interleukin 8. In conclusion, an elevated Candida antigen titer in injured adults is associated with impaired polymorphonuclear leukocyte antifungal activity. This depressed activity can be reconstituted by the addition of cytokine.

Resolution of dihydroxyeicosanoates and of dihydroxyeicosatrienoates by chiral phase chromatography

A chromatographic method is described for the direct enantiomeric characterization of 5,6-, 8,9-, 11,12-, and 14,15-vic-dihydroxyeicosatrienoic acids (DHETs), metabolites of the cytochrome P-450 arachidonate epoxygenase pathway, and of their corresponding saturated vic-dihydroxyeicosanoic acids. Following esterification, the individual methyl or pentafluorobenzyl esters are resolved by chiral-phase chromatography utilizing a Chiralcel OC or OD column. This methodology will find analytical and preparative applications since it is simple and efficient and preserves, intact, the diol functionality.

Recombinant interleukin-8 induces changes in cytosolic Ca2+ in human neutrophils

Activation of polymorphonuclear leukocytes (PMNL) by most soluble stimulants is associated with a marked increase in cytosolic free Ca2+ ([Ca2+]i). Interleukin-8 (IL-8), a monocyte-derived neutrophil chemotactic factor and potent neutrophil-activating cytokine, effectively enhanced the resting free [Ca2+]i within human PMNL in a dose-dependent manner (maximal effect with 100 ng/mL). The increase in [Ca2+]i was substantially (55%) inhibited in the absence of extracellular Ca2+. Thus, the increase was due to extra- and intracellular cooperative mobilization of Ca2+, as supported by the reduced effect of IL-8 on [Ca2+]i after quenching with Mn2+. Granulocyte-macrophage colony-stimulating factor and interferon-gamma failed to induce a change in [Ca2+]i, suggesting that they may operate through different signal pathways. Pretreatment with Bordetella pertussis toxin largely inhibited the IL-8-induced change in [Ca2+]i. Thus, IL-8-induced cooperative mobilization of intra- and extracellular Ca2+ leads to a net Ca2+ influx into the cytoplasm through a process mediated by a guanosine triphosphate-binding protein.

Cytochrome P-450 arachidonic acid epoxygenase. Regulatory control of the renal epoxygenase by dietary salt loading

The rat kidney microsomal epoxygenase catalyzed the asymmetric epoxidation of arachidonic acid to generate as major products: 8(R),9(S)-, 11(R),12(S)- and 14(S),15(R)-epoxyeicosatrienoic acids with optical purities of 97, 88, and 70%, respectively. Inhibition studies utilizing a panel of polyclonal antibodies to several rat liver cytochrome P-450 isoforms, indicated that the renal epoxygenase(s) belongs to the cytochrome P-450 2C gene family. Dietary salt, administered either as a 2-2.5% (w/v) solution in the drinking water or as a modified solid diet containing 8% NaCl (w/w), resulted in marked and selective increases in the renal microsomal epoxygenase activity (416 and 260% of controls, for the liquid and solid forms of NaCl, respectively) with no significant changes in the microsomal omega/omega-1 oxygenase or in the hepatic arachidonic acid monooxygenase reaction. Immunoblotting studies demonstrated that dietary salt induced marked increases in the concentration of a cytochrome P-450 isoform(s) recognized by polyclonal antibodies raised against human liver cytochrome P-450 2C10 or rat liver cytochrome P-450 2C11. Comparisons of the stereochemical selectivity of the induced and non-induced microsomal epoxygenase(s) with that of purified rat liver cytochrome P-450 2C11 suggest that the salt-induced protein(s) is catalytically and structurally different from liver cytochrome P-450 2C11. The in vivo significance of dietary salt in regulating the activities of the kidney endogenous arachidonic acid epoxygenase was established by the demonstration of a salt-induced 10-20-fold increase in the urinary output of epoxygenase metabolites. These results, in conjunction with published evidence demonstrating the potent biological activities of its metabolites, suggest a role for the epoxygenase in the renal response to dietary salt.

Lymphokine-activated killer cell regulation of T-cell-mediated immunity to Candida albicans

Monocytes are important accessory cells in the activation of T cells for specific antigen recognition yet little is known of their regulation. We demonstrated here that interleukin-2 (IL-2)-induced human lymphokine-activated killer (LAK) cells can inhibit monocyte antigen presentation, depending on the state of differentiation of the monocytes. Adherent monocytes cultured for 4 days in medium or granulocyte-macrophage colony-stimulating factor (GM-CSF) were found to equally process and present intact Candida albicans to autologous Percoll gradient-isolated T cells, as measured by [3H]thymidine uptake. However, only the GM-CSF-cultured monocytes were functionally inhibited by autologous 4-day IL-2-induced LAK cells. Even soluble candidal cell wall mannoprotein antigens could not be presented by these monocytes after exposure to LAK cells. Pretreatment of these monocytes with LAK cells for 1 h, followed by subsequent removal of the nonadherent LAK cells, was sufficient to cause significant inhibition, with maximal inhibition observed after 4 h. Northern (RNA) blot analysis indicated that mRNA expression for IL-1 alpha and IL-1 beta in response to C. albicans stimulation was also down-regulated in GM-CSF-cultured monocytes exposed to LAK cells. Interestingly, freshly isolated, Percoll gradient-purified large granular lymphocytes did not suppress antigen presentation in GM-CSF-treated monocytes. Another important finding was the inability of LAK cells to suppress the ability of freshly isolated or gamma interferon-cultured monocytes, which are resistant to LAK cell-mediated lysis, to present antigen to T cells. In contrast, IL-3 was similar to GM-CSF in inducing LAK cell susceptibility in monocytes. Taken together, these results indicated that IL-2 can induce LAK cells to down-regulate antigen presentation function in a select set of monocytes that have been activated by colony-stimulating factor (GM-CSF and IL-3) but not by gamma interferon. LAK cells may therefore play an important role in regulation of monocytes and their function, depending on their differentiation state.

[Effects of mixture of Astragalus membranaceus, Fructus Ligustri lucidi and Eclipta prostrata on immune function in mice]

A Chinese medicine mixture containing Astragalus membranaceus, Fructus Ligustri Lucidi and Eclipta prostrata(AFE), was fed to mice 9g/kg, 20g/kg, respectively for seven days. Observe the effects of AFE on the immune function in mice. The experiment showed that the two dosages of AFE could obviously raise the conversion percentage of lymphocytes (P < 0.01) and serum IgG level (41%-47%) of the mice. The weights of the thymus and spleensed increased in the two groups compared with those in the normal control. The larger dosage of AFE could also raise activity of Adenosine Deaminase (ADA) obviously (P < 0.01). AFE turned out a resistance to the immunosuppressive effect caused by cyclophosphamide.

Effects of endothelin-1 and conversion of big endothelin-1 in the isolated perfused rabbit lung

We examined the effects of endothelin-1 (ET-1) on pulmonary hemodynamic and transvascular fluid filtration and the conversion of big endothelin-1 (big ET-1), a precursor of ET-1, in isolated perfused rabbit lungs at constant vascular and airway pressures. Furthermore we examined whether ET-1 contributes to cyclooxygenase metabolism. The perfusate flow decreased significantly after bolus administration of 1 or 0.1 nmol of ET-1. Lung weight did not increase throughout the experimental period. Big ET-1- (1 nmol) induced decrease in the flow was slow in developing, although the maximum response was comparable to that induced by the same dose of ET-1. The concentration of bit ET-1 in the perfusate progressively decreased, while that of ET-1 increased in a time-dependent manner. Phosphoramidon, an inhibitor of metalloproteinase, suppressed the pressor effect of big ET-1 (P less than 0.01) and the increase in the concentration of ET-1 in the perfusate (P less than 0.05). The present findings provide the first evidence suggesting that the potent vasocontractile effect of big ET-1 in pulmonary circulation can be attributed to the production of ET-1 by the conversion from big ET-1 in the vascular bed. ET-1-induced perfusate flow changes were not affected by indomethacin, and the concentration of 6-ketoprostaglandin F1 alpha, a metabolite of prostacyclin, did not increase after ET-1 administration.

[Cost-effectiveness analysis of short-term course and regular course of antithyroid drug therapy for Graves' disease]

One hundred and- eighteen newly diagnosed patients with Graves' disease were treated by tapazole for 6 months (short-term course) and followed up for another 12 months. Forty three percent remission rate was found in this group. A regular course of antithyroid drug therapy for 1.5-2 years with 50% remission rate was taken as control. Cost-effectiveness analysis was made to compare the cost in the two different kinds of therapy. The results showed that the total costs of the treatment per 100 cases were 17,746 yuan for the short-term therapy and 30,708 yuan for the regular therapy, with an average of 412.7 yuan and 614.2 yuan per case respectively. In comparison with the short-term therapy, the regular course could remit 7 more cases at a cost of 12,962.40 yuan, with an average of 1851.80 yuan per case. Therefore, the cost was high by prolonged course of therapy to increase slightly remission rate, although it could remit a few more cases. This study suggests that six-month treatment is preferable for those who live in the rural or remote area where the economy was less developed. A longer course of therapy may be unnecessary for those who have been treated by antithyroid drugs for 6 months or longer and are predicted to obtain a possible prolonged remission.