摘要:

AbstractChemotactic activity for human polymorphonuclear leukocytes (PMNL) was detected in serum‐free conditioned media 1 to 4 hr after monolayers of calf pulmonary artery endothelial cells were pretreated with phorbol myristate acetate (PMA). Chemotactic activity was increased in conditioned media following pretreatment with either PMA or the less lipophilic active phorbol ester, 4‐β‐phorbol‐12,13‐dibutyrate (P(Bu)2) in a dose‐dependent manner. Chemotactic activity of conditioned media from PMA‐treated endothelial cells was confirmed by checkerboard analysis. The chemotactic activity in conditioned media from PMA‐pretreated endothelial cells was completely inhibited by pretreating endothelial cells with either cycloheximide, actinomycin D, or the lipooxygenase inhibitor, diethylcarbamazine. Furthermore, the chemotactic activity was heat‐stable, inhibited by trypsin treatment, and present in both aqueous and lipid phases after ether extraction. The data demonstrate that pulmonary artery endothelial cells exposed to active phorbol esters release potent chemotactic factor(s) for PMNL. These findings suggest a role for activators of protein kinase C in mediating endothelial cell release of chemotactic factor(s) that may be important in the directed migration of circulating leukocytes to sites of vascular injury.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.1

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractThe phosphatidylinositol (PI)‐specific phospholipase C (PLC) activity contained in sonicates of casein‐elicited (4‐6 hr) rat neutrophils has been identified and characterized. With phosphatidylinositol (PI) as the substrate, PLC activity is found both in the supernate and pellet of a 100,000gspin of the neutrophil sonicate. Further fractionation of the crude sonicate by centrifugation on discontinuous sucrose gradients indicates that the PLC activity is predominantly cytosolic with lesser amounts of activity found in the plasma membrane and granule enriched fractions. Hydrolysis of PI by the sonicate PLC is linear for 15‐20 min at 37° and also with respect to the amount of sonicate protein added. The enzyme shows selectivity for PI with little, if any, hydrolytic activity towards other phospholipids such as phosphatidylethanolamine (PE), phosphatidylserine (PS), or phosphatidylcholine (PC). The PLC activity has a pH optimum of 5.5‐6.0, is enhanced 1.5‐3‐fold by the addition of deoxycholate, and is Ca++dependent. Kinetic analysis of the PLC hydrolysis of PI yields an apparent Km of 240 ± 85 μM and a Vmax of 34.3 ± 17.0 nmol/min/mg protein (n = 3). Similarly, when phosphatidylinositol 4,5 bisphosphate (PIP2) is used as substrate, an apparent Km of 109 ± 66 μM and a Vmax of 14.3 ± 10.4 nmol/min/mg (n = 3) protein is obtained. These data suggest that PIP2may be a slightly better substrate for the PMN PLC relative to PI. Finally, a variety of drugs previously reported to inhibit platelet PLC activity in vitro were tested for their ability to inhibit rat PMN PLC. Of the compounds tested, none were potent (i.e., IC50values 100 μM) inhibitors of the PMN PLC.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.8

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution and concentration of surface ionogenic groups on murine peritoneal macrophages and the responses of their plasmalemma to charged markers were investigated by electron microscopy. Quantitation of the distribution of cationized ferritin (CF) as a marker for anionic groups on fixed cells revealed surface anions on invaginated parts of the plasmalemma to be fewer than those on flat or projecting segments. Cationic groups on the surface membrane, however, could not be labeled with anionized ferritin (AF). Interaction of viable macrophages with cationic particles at 37° resulted in their “internalization” within vesicles and coated pits and a closer apposition between many segments of plasmalemma than with neutral or anionic substances. The process occurred unaltered at 4° and was unaffected by cytochalasin B and colchicine, suggesting that this close apposition between segments of plasmalemma resulted from neutralization of surface negative electrostatic charges by the cationic material and did not reflect endocytosis.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.17

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractPrevious studies have shown that the injection of estrogen into immature rats leads to an influx of leukocytes into the uterus. Using immunoperoxidase staining and monoclonal antibodies, we have characterized the nature of the infiltrating leukocytes in frozen sections of immature rat uteri obtained following the injection of estrogen, estrogen plus pertussigen, and the antiestrogen LY117018. Estradiol treatment for 2 days resulted in a significant increase in the number of uterine eosinophils, CD4 (W3/W25)‐positive helper/inducer T lymphocytes, macrophages (MRC OX‐42‐positive cells), and Ia (MRC OX‐6)‐positive cells. In contrast, estradiol treatment failed to elicit a significant increase in the number of CD8 (MRC OX‐8)‐positive uterine cytotoxic/suppressor T lymphocytes and/or natural killer cells, as well as MAR 18.5‐ and/or MRC OX‐12‐positive B lymphocytes. The injection of LY117018 failed to elicit any changes in the number of cells expressing any of the phenotypes under investigation. The simultaneous injection of pertussigen, the major toxin responsible for the leukocytosis‐ and lymphocytosis‐promoting activity ofBordetella pertussis, inhibited the estrogen‐induced influx of eosinophils, macrophages (MRC OX‐42‐positive cells), and Ia (MRC OX‐6)‐positive cells but failed to prevent the influx of CD4 (W3/25) positive helper/inducer T lymphocytes. These results indicate that, in the immature rat, significant differences may exist in the susceptibility of various cell populations to the effects of estrogen, particularly with regard to uterine influx following estrogen stimulation. In addition, our observations suggest that either 1) the CD4‐positive cells infiltrating the uterus following estrogen treatment may use a nonpertussigen‐sensitive mechanism for chemotactic factor‐receptor signal transduction or 2) a subpopulation of resident uterine cells can be induced to express the CD4 antigen following estrogen and/or estrogen plus pertussigen treatment.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.27

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractProtein kinase C activity was studied in superoxide‐producing human polymorphonuclear leukocytes. Using equivalent cell concentrations, superoxide production and particulate fraction‐associated protein kinase C activity increased in parallel in phorbol 12‐myristate 13‐acetate (PMA), oleoyl‐acetyl‐glycerol (OAG), opsonized zymosan, and A23187‐activated leukocytes. Also, an increase in particulate fraction‐associated phospholipid‐independent kinase activity was observed upon stimulation with these activators. In contrast, in formyl‐methionyl‐leucine‐phenylalanine (FMLP)‐activated cells the increase in superoxide production was only accompanied by an increase in particulate fraction‐associated protein kinase C activity if the cells were pretreated with cytochalasin B. Purified protein kinase C activity was stimulated by OAG and PMA, whereas no stimulation was observed using A23187 or opsonized zymosan. It is suggested that the activation induced in human neutrophils by PMA, OAG, opsonized zymosan, and A23187 involves a thight membrane association of phospholipid‐dependent and ‐independent protein kinase activity. This contrasts to FMLP‐activated neutrophils, in which a membrane‐bound form is only observed after pretreatment with cytochalasin B.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.33

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractWe have characterized the β‐adrenergic receptor binding site and the β‐adrenergic cAMP response of the HL‐60 cell. The hydrophilic ligand [3H]‐(–)‐CGP‐12177 was specifically and reversibly bound to one single class of binding sites (Kd220 pM and Bmax1,970 sites/cell). The adrenergic agonists inhibited the specific radioligand binding. The order of potency was isoproterenol>epinephrine>norepinephrine. The β‐2 selective antagonist ICI 118551 had a binding affinity 3 orders of potency higher than the β‐1 selective antagonist, atenolol. The adrenergic agonists elevated the cAMP accumulation in a concentration‐dependent mode. The order of potency was isoproterenol>epinephrine>norepinephrine. Both the binding and the functional studies revealed stereospecificity and reversibility. The present data show that HL‐60 cells possess β‐2 adrenergic receptors functionally coupled to adenylate cyclase.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.41

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractThe toxicity of guanosine and deoxyguanosine in the presence or absence of the purine nucleoside phosphorylase inhibitor, 8‐aminoguanosine, for malignant lymphoid cell lines and mitogen‐stimulated peripheral blood lymphocytes has been studied. Deoxyguanosine inhibited the proliferation of lymphoid cells more strongly than guanosine. Addition of 100 μM 8‐aminoguanosine neither enhanced nor diminished the toxicity of guanosine to the lymphoid cells. Only the toxicity of deoxyguanosine for the leukemic T cell line, MOLT 4, and the leukemic nonBnonT cell line, KM‐3, was enhanced by the addition of 100 μM 8‐aminoguanosine. These data suggest a possible role of purine nucleoside phosphorylase inhibitors in the treatment of lymphoproliferative disorders of the T‐acute lymphoblastic leukemia (ALL) as well as the nonBnonT‐ALL subclass.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.46

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractThe human monocyte cell line, U937, can be induced to terminally differentiate into macrophage‐like cells when treated with gamma‐interferon. However, if these cells were treated with gamma‐interferon and esculetin, an inhibitor of the lipoxygenase pathway, or BW755C, an inhibitor of both the lipoxygenase and the cyclooxygenase pathways, a marked inhibition in cellular differentiation occurred. In contrast, inhibitors of only the cyclooxygenase pathway had no effect on differentiation. These studies suggest a role for lipoxygenase products of arachidonic acid in the differentiation of the human U937 cell line. Arachidonic acid utilized in the production of eicosanoids is derived from phospholipids by the action of phospholipase A2and phospholipase C. When U937 cells were cultured in medium supplemented with gamma‐interferon, there was a striking increase in the level of phosphatidylcholine and phosphatidylethanolamine‐specific phospholipase A2activities and phosphatidylinositol‐specific phospholipase C activity as compared to control cells. Morever, although there was not a significant difference in the incorporation of labeled arachidonic acid or linoleic acid into the major phospholipids of differentiated U937 cells as compared to undifferentiated control cells, there was a marked increase in the relative amount of the labeled arachidonic acid released from the differentiated cells as lipoxygenase products compared to cyclooxygenase products. These data suggest that lipoxygenase products may be essential in the differentiation process of U937 cells and that enhanced phospholipase enzyme activities that occur during differentiation help explain how arachidonic acid becomes available to form lipoxygenase products.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.51

出版商:Wiley    

年代:1988

数据来源: WILEY

摘要:

AbstractTreatment of EMT‐6 mammary adenocarcinoma cells with gamma interferon (rMuIFNγ) plus tumor necrosis factor (rMuTNFα) and/or interleukin‐1 (rHuIL‐1α) causes release of iron‐55 label, inhibition of DNA replication, and inhibition of aconitase activity. In addition, the same combinations of cytokines induce EMT‐6 cells to synthesize L‐citrulline, nitrite, and nitrate directly from L‐arginine. Lipopolysaccharide (LPS) can act as a cofactor in the induction of these metabolic effects when added to EMT‐6 cells in the presence of rMuIFNγ. The results show that increased levels of cytokines in the microenvironment can induce a novel effector pathway in somatic cells not specialized for host defense, resulting in specific metabolic effects as well as the inhibition of cellular proliferation.

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.58

出版商:Wiley    

年代:1988

数据来源: WILEY

ISSN:0741-5400    

DOI:10.1002/jlb.44.1.i

出版商:Wiley    

年代:1988

数据来源: WILEY