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F Patrone

Publications and source records attributed to F Patrone.

At least 55 records · Page 3Linked to original sources
PubMed1989

Defective antibody-dependent tumour cell lysis by neutrophils from cancer patients.

Neutrophil antibody-dependent cellular cytotoxicity (ADCC) against Raji target cells was studied in 32 patients with lung or gastro-intestinal carcinoma and 25 healthy controls. Seventeen of the patients (53%) had defective ADCC. Moreover, neutrophils obtained from patients with defective ADCC were found to bind IgG-coated target cells normally. Thus, the defect responsible for the impaired lysis appears to be distal to the Fc receptor (FcR)-mediated target cell binding by neutrophils.

Adult↗
PubMed1988

Monocyte-derived macrophages as helper cells in monocyte-mediated cytolysis.

Human peripheral blood monocytes (M), incubated with opsonized zymosan particles (OPZ), lysed human erythrocyte (RBC) targets, as detected by a 51Cr release method. Conversely, cells derived in vitro from M (monocyte-derived macrophages, MDM) were ineffective. When added to the M-RBC system, MDM enhanced the lysis. The lysis by M and M plus MDM was prevented by catalase, azide and amino acids (alanine, taurine), consistent with the requirement for hypochlorous acid (HOCl). Moreover, MDM per se incapable of generating HOCl augmented the HOCl recovery from the M-RBC system. The results provide evidence for a previously unrecognized form of interaction between two distinct populations of mononuclear phagocytes.

Amino Acids↗
PubMed1988

Neutrophil-induced depletion of adenosine triphosphate in target cells: evidence for a hypochlorous acid-mediated process.

Human neutrophils, incubated with phorbol myristate acetate (PMA), caused a rapid and substantial adenosine triphosphate (ATP) depletion in lymphoblastoid Daudi cells without producing lysis. Catalase (which destroys hydrogen peroxide), taurine and methionine (which scavenge hypochlorous acid), and chloride omission from the medium prevented the ATP fall. An ATP depletion comparable to that induced by neutrophils was observed by replacing neutrophils with an appropriate myeloperoxidase-H2O2-Cl- enzymatic system. Together, these data suggest that the neutrophil ATP depleting activity involves the myeloperoxidase-catalyzed transformation of H2O2 into HOCl. Moreover, the free H2O2 remaining in the neutrophil extracellular environment is ineffective. In fact, a comparable amount of enzymatically generated H2O2 did not cause Daudi cell ATP loss. A direct role for H2O2 in the neutrophil-induced Daudi cell ATP depletion was observed only under artificial conditions, that is, in the presence of the heme enzyme inhibitor azide, which prevented the HOCl production but dramatically augmented the extracellular H2O2 level. Similar levels of ATP depletion in Daudi cells were induced by amounts of reagent HOCl comparable to those generated by neutrophils. As the generated HOCl can rapidly react with a variety of neutrophil-derived nitrogenous compounds (primarily ammonia and taurine) to yield chloramines, these chlorinated oxidants might contribute to the neutrophil-mediated ATP depletion. Nevertheless, the main and well-characterized chloramines (ammonia-derived monochloramine, NH2Cl, and taurine monochloramine, TauNHCl) were devoid of ATP-depleting capacity. Thus, the results suggest that the neutrophil-induced ATP depletion in Daudi cells is HOCl-dependent, is not mediated by NH2Cl or TauNHCl, and could be promoted either by HOCl directly or by an unknown derivative oxidant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1988

Cytolysis mediated by phagocytosing neutrophils. Influence of the presence of an alternative target cell population.

When added to the hypochlorous acid (HOCl)-dependent cytolytic system constituted of opsonized zymosan (OPZ)-triggered neutrophils and chicken erythrocyte (CRBC) targets, human erythrocytes (HRBCs) inhibited the lysis. The replacement of HRBCs with cells pretreated with amino-triazole (AT) to inactivate catalase prevented the HRBC inhibitory effect almost completely. HRBCs, pretreated with carmustine (BCNU) to inhibit glutathione cycle activity, behaved as untreated cells. Thus, HRBCs appear to protect CRBCs via an AT-inhibitable, i.e. catalase-dependent, process. When measured under conditions similar to those used for the lytic assay, both the hydrogen peroxide (H2O2) and the HOCl recovery from the neutrophil-CRBC system was reduced by HRBCs and restored by pulsing HRBCs with AT but not BCNU. The results suggest that HRBC catalase rescues CRBCs from neutrophil-delivered attack by "stealing" H2O2 from the neutrophil HOCl-generating myeloperoxidase (MPO)-H2O2 system.

Animals↗
PubMed1987

Augmentation of neutrophil-mediated erythrocyte lysis by cells derived in vitro from human monocytes.

Neutrophilic polymorphonuclear leukocytes (PMNs) were incubated with opsonized zymosan and lysed human erythrocytes (RBCs) as measured by a 51Cr release method. Conversely, myeloperoxidase (MPO)-negative hydrogen peroxide (H2O2)-generating cells, derived in vitro from human monocytes (monocyte-derived cells (MDCs), were ineffective per se but capable of augmenting the lysis by PMNs. The lysis by PMNs and PMNs plus MDCs was inhibited by catalase, azide, taurine, and alanine, consistent with the requirement for hypochlorous acid (HOCl). As detected under conditions similar to those used for lytic assays, MDCs failed to produce HOCl but augmented the HOCl recovery from the PMN-RBC system. Moreover, when the extent of the lysis was plotted as a function of the HOCl recovery, a positive linear relationship was found. Although the actual size of the H2O2 extracellular pool could not be measured because of the inexistence of a reliable assay to probe our cytolytic model without perturbing the equilibrium of the system, the results presented suggest that MDCs enhance the PMN-mediated lysis by improving the HOCl production, presumably by supplying extra amounts of H2O2 to be handled by PMN MPO. In fact, the events mediated by MDCs could be reproduced by using an appropriate H2O2-generating enzymatic system (glucose-glucose oxidase). The present study provides direct evidence for the possibility of cooperation between MPO-positive and MPO-negative phagocytes in exerting functions (HOCl production and, in turn, cytolysis) possibly relevant to the outcome of inflammatory processes.

Cells, Cultured↗
PubMed1987

Relationship between antibody-dependent tumour cell lysis and primary granule exocytosis by human neutrophils.

Neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) against Raji target cells and neutrophil degranulation during the ADCC process were evaluated in the presence and in the absence of different agents able to interfere with the neutrophil release of granule components (anion channel blockers, colchicine, isoproterenol, dimethylxanthine, cAMP). When used at concentrations incapable of preventing the target cell recognition by neutrophils, the majority of these agents inhibited both the ADCC and the release of myeloperoxidase (MPO, primary granule marker) and lysozyme (LZM, primary and secondary granule marker). The inhibition of the ADCC correlated strictly with the inhibition of the MPO release. Thus, the results are consistent with the hypothesis that neutrophil primary granules play a major role in the cytolytic process.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1987

Erythrocyte lysis by monocytes: investigations on the mechanism and role of the target cell hydrogen peroxide catabolizing pathways.

The erythrocyte (RBC) lysis by human monocytes incubated with opsonized zymosan particles (OPZ), was inhibited by catalase, chloride-free medium, azide and hypochlorous acid (HOCl) scavengers (taurine, alanine). These findings suggest the requirement for the HOCl-generating myeloperoxidase-hydrogen peroxide-chloride system (MPO-H2O2-Cl- system). The HOCl-dependent lysis was increased by inhibiting RBC catalase with aminotriazole (AT). Conversely, the inhibition of RBC glutathione cycle with 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) had no detectable effect. Moreover, the recovery of H2O2 and HOCl from OPZ-triggered monocytes was reduced by the presence of RBCs through a process almost completely preventable by pulsing RBCs with AT but not with BCNU. Thus, it appears that RBC targets protect themselves by consuming, primarily via catalase, significant amounts of monocyte-derived H2O2 with a consequent impairment of the HOCl generation. The results suggest a potential role of target cells in modulating the cytolysin production by monocytes.

Erythrocytes↗
PubMed1987

Antibody-dependent tumour cytolysis by human neutrophils: effect of synthetic serine esterase inhibitors and substrates.

The requirement for serine esterase activity in antibody-dependent cellular cytotoxicity (ADCC) in human neutrophils against Raji target cells has been investigated. The lysis was prevented when the serine esterase inhibitors TPCK and TLCK (chloromethyl-ketone derivatives of tosylamino acids) were introduced into the system. Moreover, neutrophils pretreated with TPCK or TLCK and washed were inhibited as well, via a process unaffected by the presence of adequate amounts of enzymatic substrates. This suggests that the inhibition mediated by TPCK and TLCK is independent of serine esterase blockade, therefore implying the inactivation of some other step crucial to the lysis. The addition of synthetic chymotrypsin substrates (tyrosine and phenylalanine esters) impaired the Raji cell lysis in a dose-related manner without altering the constitution of neutrophil-target conjugates. Trypsin ester substrates were ineffective. These results are in agreement with the involvement of a serine esterase activity with chymotrypsin-like specificity, which should participate in the lysis at a post-binding step. We conclude that neutrophil-mediated ADCC, as developed in our model system, needs the intervention of a serine esterase or esterases, like other systems of cell-mediated cytotoxicity.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

Expression of cytolytic functions in HL-60 leukaemic cells after induction of polymorphonuclear leukocyte differentiation.

Mature polymorphonuclear leukocytes (PMN) are capable of mediating phorbol myristate acetate (PMA)- and antibody (A)-dependent cellular cytotoxicity (DCC) against ox red blood cells (ORBC) by using oxidative means. The purpose of the present study was to investigate the acquirement of these cytotoxic functions during PMN ontogeny, using the promyelocytic HL-60 cell line as a model for PMN differentiation. HL-60 cells were induced to differentiate along the PMN pathway by exposure to dimethyl sulfoxide (DMSO). Uninduced HL-60 cells were found to be completely devoid of PMA-DCC and ADCC activity. DMSO-induced cells progressively acquired the capacity to kill ORBC and to undergo the activation of oxidative metabolic burst when triggered by PMA. Despite approximately 40% of them also were capable of binding IgG-sensitized ORBC, no ADCC activity and respiratory burst activation was observed: this finding indicates that maturing HL-60 cells require a more complete maturation than that induced by DMSO to actually exert ADCC. Together the results suggest that: a. the acquirement of both PMA-DCC and ADCC potential is a post-promyelocytic event; b. the cytotoxicity activating stimuli, PMA and IgG-coated targets, follow different post-receptor transductional pathways to trigger the effector cell lytic systems: only the PMA receptor-linked pathway develops during DMSO-driven differentiation of HL-60 cells.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

Inhibition of neutrophil cytolysin production by target cells.

Neutrophils, triggered by heat-aggregated human IgG (Agg.IgG), were found to lyse chicken red blood cells (CRBC) as determined by a 51Cr release method. The lysis was inhibited by azide, catalase, chloride-free medium and amino acids, suggesting the requirement for myeloperoxidase (MPO), hydrogen peroxide (H2O2), chloride ions (Cl-), and hypochlorous acid (HOC1), respectively. These results indicate that neutrophils lyse CRBC through an HOCl-(ie, MPO-H2O2-Cl-) dependent process. Although HOCl can react with neutrophil-derived nitrogenous (N-) compounds to yield chloramines, the main and well-characterized chloramines did not play a direct role in the lysis of CRBC in our model system. Thus, it appears that lysis is due either to HOCl or to an unknown compound derived from and with characteristics similar to HOCl. When CRBC were replaced with HRBC targets, no lysis could be observed. Treatment of HRBC with carmustine, to inhibit the glutathione cycle, did not affect the cell resistance to lysis by neutrophils. Conversely, the inhibition of HRBC catalase activity with aminotriazole (AT) made the cells susceptible to neutrophil-mediated HOCl-dependent lysis: this suggests that HRBC escape lysis by neutrophils through an AT-inhibitable, ie catalase-dependent, process. Through an identical catalase-dependent process, HRBC were capable of efficiently preventing the H2O2 and HOCl recovery from Agg.IgG-triggered neutrophils, tested under experimental conditions similar to those used for cytolytic assays. Together, these data suggest that HRBC targets, endowed with high catalase activity, escape neutrophil-mediated lysis by consuming (by catalase) neutrophil-derived H2O2, so that HOCl cannot be produced in amounts sufficient to promote lysis. Parallel experiments, performed with AT-treated CRBC, showed that these cells, endowed with a relatively low catalase content, only partially limit neutrophil cytolytic efficiency by a process qualitatively similar to that observed with HRBC targets. The results provide evidence that target cells can restrain neutrophil cytolytic efficiency by interfering with the MPO-H2O2-Cl system through their catalase activity.

Amitrole↗
PubMed1986

Role of hypochlorous acid and chloramines in the extracellular cytolysis by neutrophil polymorphonuclear leukocytes.

The lysis of human red blood cells (HRBC) by neutrophil polymorphonuclear leukocytes (PMN), triggered with opsonized zymosan (OPZ) particles, was inhibited by azide, catalase, Cl- -free medium and amino acids indicating the involvement of myeloperoxidase (MPO), hydrogen peroxide (H2O2), Cl- ions and hypochlorous acid (HOCl) respectively. Thus, the cytolytic process depends on the following reaction: (Formula: see text). Because the oxidizing agent HOCl is also the precursor of the chloramines, a group of oxidants formed by the reaction between HOCl and PMN-derived ammonia (NH4+) or amines (R-NH2), the observed HRBC lysis can be theoretically due to HOCl and/or chloramines. Nevertheless, we found that PMN-mediated cytotoxicity occurs as an unidirectional process, being HRBC targets lysed and PMN unaffected. This finding indicates that the cytotoxin must be relatively more efficient against HRBC as compared with PMN. In fact, reagent HOCl (used at concentrations comparable to those generated by PMN) but not chloramines displayed such a type of property. Taken together, the data suggest that HRBC are killed by PMN-derived HOCl without the requirement for chloramines: this implies that NH4+ and R-NH2, released by PMN, act as down-modulators of the cytotoxic process, serving as HOCl trapping agents.

Animals↗
PubMed1986

Interference of target cell catalase with an early step of the neutrophil cytolytic pathway.

The hypochlorous acid (HOCL)-dependent lysis of human red blood cells (HRBC) targets by neutrophils, activated with opsonized zymosan particles (OPZ), was increased by inhibiting HRBC catalatic activity with aminotriazole (AT; HRBCAT). The inhibition of HRBC glutathione cycle activity with carmustine (BCNU; HRBCBCNU) had no effect. In addition, the recovery of hydrogen peroxide (H2O2) and HOCL from neutrophils, activated under conditions similar to those used for cytotoxicity assay, was reduced by the presence of HRBC and restored by replacing HRBC with HRBCAT, but not with HRBCBCNU. Linear relationships were found between the increments in the neutrophil-mediated lysis, observed by using HRBCAT instead of HRBC, and the increments in the H2O2 or HOCL recovery, detected by replacing HRBC with HRBCAT. Together these data, coupled with the results obtained by probing neutrophil cytolysis with chemical agents, suggest that the increased cytolytic efficiency displayed by neutrophils against HRBCAT, inhibited in their catalatic activity, is due to an enhanced availability of neutrophil-derived H2O2, with a consequent enhancement in the HOCL production (according to the following reaction: (formula; see text). Thus it appears that HRBC catalase restrains the neutrophil cytolytic activity, by interfering with an early step of the pathway through which neutrophils generate cytotoxins.

Amitrole↗
PubMed1985

Restoration of defective EAG-rosetting capacity of cancer patient neutrophils by levamisole.

Levamisole, used in vitro at therapeutic concentrations, was found able to restore the defective Fc-receptor activity of cancer patient neutrophils. In addition, the drug prevented the inhibition of normal neutrophils Fc-receptor function by cancer patient sera. The neutrophil Fc-receptor function was also restored in six of seven cancer patients after in vivo administration of levamisole (2.5 mg/Kg/day for 3 days). Due to the central role played by the Fc-receptor function in host defence mechanisms, including phagocytosis as well as antibody dependent cellular cytotoxicity, the capacity of levamisole to restore defective neutrophil Fc-receptor function in cancer patients could contribute to the "immunomodulating" effect of the drug.

Cell Membrane↗
PubMed1985

Cellular cytotoxicity mediated by granule-depleted neutrophil cytoplasts.

Neutrophil-derived nucleus-and granule-free cytoplasts, consisting of cytosol enclosed by an intact plasma membrane, were able to destroy 51Cr-labelled ox red blood cells (ORBC) in the presence of phorbol myristate acetate (PMA). The slope of the target cell lysis vs the log of the cytoplast number was similar to that observed with neutrophils as effector cells. Nevertheless, a number of cytoplasts 60-80 times higher than that of neutrophils was required to obtain a common level of cytotoxicity. The ability of cytoplasts and neutrophils to lyse ORBC was completely abolished by catalase and unaffected by superoxide dismutase and mannitol, suggesting the involvement of hydrogen peroxide in the target cell damage. Addition of myeloperoxidase (MPO) to cytoplasts increased lysis. The MPO lysis by cytoplasts, except when experiments were carried out in the presence of MPO. The results indicate that neutrophil cytosol and plasma membrane represent the basic requirement for the PMA-dependent cytolytic process, whereas MPO behaves as a device to amplify lysis.

Catalase↗
PubMed1985

Extracellular cytotoxicity by phagocytosing polymorphonuclear neutrophilic leukocytes: enhancement by a chemotactic stimulus.

This study investigated the influence of a chemotactic stimulus on the extracellular cytotoxicity mediated by phagocytosing polymorphonuclear neutrophilic leukocytes (PMN). We used N-formyl-methionyl-leucyl-phenylalanine (FMLP) as chemotactic peptide, opsonized zymosan as phagocytosable particle, and ox red blood cells (ORBC) as extracellular bystander targets. Phagocytosing PMN were found to kill ORBC efficiently, as determined by the 51Cr-release assay. FMLP, at the concentration of 100 nM, significantly enhanced the target cell lysis. PMN from two patients with chronic granulomatous disease and normal PMN plus catalase or free radical scavengers (mannitol, benzoate, histidine) were completely devoid of cytolytic activity both in the presence and in the absence of FMLP. The results indicate that the target cell lysis by phagocytosing PMN as well as the chemotactic peptide-related amplification of the lysis itself depend on the expression of the PMN oxidative cytotoxic potential. A similar response to a chemotactic stimulus in vivo could provide a mechanism for regulating PMN-dependent cytotoxic and inflammatory processes.

Catalase↗
PubMed1985

Erythrocyte lysis by PMA-triggered neutrophil polymorphonuclears: evidence for an hypochlorous acid-dependent process.

Human red blood cells (HRBC) were efficiently lysed when incubated with neutrophil polymorphonuclears (PMN) in the presence of phorbol-myristate-acetate (PMA), as detected by a 4-hr 51Cr release assay. The lysis was virtually absent in the presence of catalase, azide or cyanide and in the absence of chloride ions. These findings indicate the involvement of the myeloperoxidase (MPO)-hydrogen peroxide (H2O2)-chloride (Cl-) system in the cytolytic process. As the MPO-H2O2-Cl- system is capable of generating the powerful oxidant hypochlorous acid (HOCl), cytotoxicity assays were performed in the presence of taurine, glycine, serine and valine to scavenge this potentially lytic agent. Each of these compounds efficiently inhibited the HRBC lysis by PMA-triggered PMN, as well as the lysis caused by HOCl in a cell-free system. Thus, the results suggest that HOCl, or an agent with similar reactivity, plays a key role in the PMA-dependent PMN-mediated cytotoxicity against HRBC targets.

Chlorine↗
PubMed1985

Down-regulation of K cell activity by neutrophils.

Human neutrophils, activated by phorbol-myristate acetate (PMA), (A-neutrophils), were found to suppress lymphocytic killer (K) cell-mediated antibody-dependent cellular cytotoxicity (ADCC). Resting (R) neutrophils, ie, PMA-untreated cells, were completely ineffective. Suppression was optimal when A-neutrophils were added at the beginning of the ADCC assay. Furthermore, A-neutrophils were found to cause an approximately 80% reduction in the number of Raji target cell-bound lymphocytes. These data indicate that A-neutrophils inhibit K cell activity by interfering with the target cell recognition. A-neutrophils were capable of reducing the percentage of Fc receptor (FcR)-bearing lymphocytes with a half-time of 7.2 minutes, through a process preventable by the serine-protease inhibitors tosyl-lysine-chloromethyl ketone (TLCK) and lima bean trypsin inhibitor (LBTI). Conversely, A-neutrophils caused a very slow decrease in the amount of Raji cell-bound antibodies, as detected by the complement-mediated lytic assay. Thus, only lymphocyte FcR structures seem to be highly susceptible to neutrophil-derived TLCK- and LBTI-inhibitable proteases. Furthermore, supernatants from A-neutrophils were found to inhibit K cell ADCC and lymphocyte binding to Raji target cells. In addition, LBTI prevented the A-neutrophil-dependent and the supernatant-dependent inhibition of both K cell ADCC activity and lymphocyte-target cell conjugate formation. Together these data suggest that A-neutrophils suppress K cell function through a protease-mediated impairment of the FcR binding capacity. The results provide evidence that human neutrophils are endowed with mechanisms to regulate K cell ADCC activity.

Antibody-Dependent Cell Cytotoxicity↗