摘要:

AbstractMultinucleated giant cells (MGCs) are an integral part of the host immune response to infectious disease and are seen in granulomas induced by pathogens and inorganic substances. We have developed a novel system for the production and study of MGCs: Peripheral blood monocytes, when cultured in the presence of anti–class II major histocompatibility complex monoclonal antibodies (MHC mAb's) and lymphocyte‐conditioned medium form MGCs within 48 h. MGC formation was strictly dependent on the presence of anti–class II MHC mAb's and lymphocyte‐conditioned medium. MGC formation was not induced by mAb's to other monocyte surface proteins. None of the previously identified macrophage fusion factors (calcitriol, interleukin 4, interferon‐γ) were able to substitute for the lymphocyte‐conditioned medium in our assay; however, the conditioned medium could be replaced by the phorbol ester phorbol 12‐myristate 13‐acetate. We have also demonstrated that the induction of MGCs by anti–class II MHC antibody and phorbol ester requires protein kinase C activity, because MGC formation was totally inhibited by the protein kinase C inhibitors staurosporine and H‐7. In analyzing the signal induced by anti–class II MHC mAb's we have demonstrated that cross‐linking of the class II MHC antigens with intact mAb's, or with F(ab')2fragments of anti–class II MHC mAb's and F(ab')2fragments of rabbit antimouse (RAM) immunoglobulin G, produced an intracellular calcium rise. Furthermore, using the calcium channel blocker verapamil, it was demonstrated that calcium channel activity is necessary for MGC formation. These data support the view that MGC formation is a tightly regulated differentiative pathway of peripheral blood monocytes that is dependent on protein kinase C second messenger systems and involves an inrease in intracellular calcium concentration.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.199

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractMetabolism of platelet‐activating factor (PAF) was studied in cultured polymorphonuclear neutrophils (PMNs) obtained from Pichinde virus–infected strain 13 guinea pigs. Neutrophils obtained from control and infected guinea pigs on postinoculation days 10 and 14 were incubated with [3H]lyso‐PAF, [3H]PAF, or [3H]acetate. After incubation for 1 h at 37°C, formation of [3H]acyl‐PAF from either [3H]lyso‐PAF or [3H]PAF increased significantly in PMNs from infected guinea pigs compared to control PMNs. Furthermore, total radioactivity from [3H]lyso‐PAF or [3H]PAF was higher in PMNs from infected animals than in those from controls. However, compared to PAF production by control PMNs, production of PAF by infected PMNs was unchanged. These results suggest that PMNs may not be the major source of increased blood PAF levels during Pichinde viral disease.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.210

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThe motility and deformability of lymphokine‐activated killer cells, purified by their adherence to plastic (A‐LAK cells), was investigated in vivo and in vitro. In vitro, A‐LAK cells were observed as intrinsically motile cells. They continuously changed their shape while forming protopods or pseudopods and crawled over the culture surface. A‐LAK cells were able to migrate across micropores of 3 μm diameter, which was three times smaller than the average diameter of an A‐LAK cell. Even in the absence of serum factors and of interleukin‐2 (IL‐2), more than half of the inoculated cells migrated across such micropore membranes within 18 h. Electron microscopic examination of these micropore membranes showed that the A‐LAK cells were highly deformable. A‐LAK cells also migrated across a confluent monolayer of endothelium‐like 10T1/2 cells. After 24 h incubation on the monolayers, about 20% of the A‐LAK cells were found underneath the monolayer. There, they actively moved in the narrow space between the monolayer and the bottom of the culture dish. In vivo IL‐2‐activated cells showing the large granular lymphocyte morphology accumulated in the hepatic microvasculature. Electron microscopic observations indicate that these cells did not accumulate by mechanical entrapment due to rigidity and size but rather by adherence to the endothelial lining of the sinusoidal capillaries. This also appeared to be the case for adoptively transferred A‐LAK cells, which were seen to be attached to the capillary wall. These observations stress the importance of adhesive entrapment to explain the accumulation of intravenously transferred LAK cells in the vascular beds.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.214

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThe present results demonstrate that macrophages from mice susceptible to infection withLeishmania mexicana amazonensissustain a higher production of granulocyte‐macrophage colony‐stimulating factor (GM‐GSF) throughout the in vitro infection than macrophages from a resistant strain. Resident macrophages from BALB/c and C57B1/10 mice were infected with promastigotes ofL. mexicana amazonensisand the amount of biologically active GM‐CSF was measured in the supernatants collected at different times of infection. Measurements were made by bone marrow and GM‐CSF/interleukin‐3 addicted cell proliferation. Because GM‐GSF is a disease‐exacerbating cytokine, its differential production by infected macrophages may be one of the mechanisms defining resistance or susceptibility to a leishmanial infection.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.220

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThe relative importance of CD4+and CD8+T cell subsets in the expression of acquired resistance to systemic infection byMycobacterium kansasiiwas determined. T cell subsets were depleted in thymectomized C57BL/6 mice by the intravenous administration of monoclonal antibodies directed against the relevant T cell determinants. Depletion of the CD4+subset exacerbated the severity of the infection in intravenously challenged mice. This effect was apparent in the first 2 weeks of the infection and persisted throughout the 12 weeks of the study. On the other hand, depletion of the CD8+cells had no apparent effect on the growth curves. Infections byMycobacterium tuberculosisErdman or bacille Calmette‐Guérin (BCG) Pasteur were also substantially enhanced by CD4 depletion, but not by the depletion of CD8+cells. The effect of subset depletion on infections byM.tuberculosisand BCG was examined in both innately susceptible C57BL/6 mice and innately resistant B6D2 mice.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.225

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractInfluenza A virus (IAV) causes both activation and deactivation of the human neutrophil, which may, respectively, contribute to host defense against the virus and enhanced susceptibility to bacterial superinfection. We have shown that certain features of neutrophil activation by IAV are distinctive compared with activation by chemoattractants in terms of both the stoichiometry of the respiratory burst response and the signal transduction events that precede it. We here demonstrate that related myxoviruses as well as sialic acid–binding lectins elicit a respiratory burst response similar to that induced by IAV, in which hydrogen peroxide is formed with minimal accompanying superoxide generation. Brief preincubation of neutrophils with these agents fully inhibits subsequent activation by IAV, implying that they are binding to the same surface membrane components as IAV. Preincubation withLimax flavusagglutinin (LFA) does, in fact, substantially reduce binding of radiolabeled IAV to the neutrophil. This lectin, like IAV, both activates and deactivates the neutrophil. As in the case of IAV, LFA‐induced activation (1) is mediated via stimulation of phospholipase C, (2) is pertussis toxin insensitive, and (3) entails a lesser contribution of calcium influx than is the case for chemoattractants.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.230

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractInterleukin 6 (IL‐6) is a multifunctional cytokine with an important role in immunity. We analyzed the effect of recombinant human IL‐6 in combination with 1α,25‐dihydroxyvitamin D3(Vit. D3) on differentiation of the human myeloid leukemic cell lines U937 and HL‐60 with respect to alterations in antigen expression and functional activity. Of a panel of antigens analyzed, only CD11b (the α chain of CR3), and GD14 (a cell surface protein recognizing the lipopolysaccharide‐binding protein‐lipopolysaccharide complex) had significantly increased expression. Expression of ICAM‐1 (CD54), a ligand for LFA‐1, was also found to be enhanced with a concomitant increase of ICAM‐1 mRNA levels. Enhanced nonspecific esterase levels and induction of respiratory burst activity confirmed that cell differentiation was induced. Furthermore, IL‐6 and Vit. D3had a profound effect on functional activities, as shown by enhancement of rosetting between sheep erythrocytes, sensitized with C3bi (EAC), and either U937 or HL‐60 cells. Also, phorbol myristate acetate–induced homotypic adhesion of U937, which is ICAM‐1 dependent, was markedly induced by these agents. These results indicate an important role of IL‐6 and Vit. D3in myeloid cell Function and development.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.237

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractResistance of mice toSalmonella, typhimuriumin the early phase of infection is known to be controlled by the expression of chromosome 1 locusIty. To clarify the mechanism by which the genetically resistant (Ityr) mice can overcome the first phase of salmonellosis, the early response in DBA/2 (Ityr) and BALB/c (Itys) mice was compared after a subcutaneous injection ofS. typhimurium. In both strains, the growth ofS. typhimuriumwas controlled in livers and Kupffer cells until day 3, but thereafter the bacteria multiplied rapidly in BALB/c mice. Over the first 2 days nonspecific responses (changes in levels of blood leukocytes, plasma iron, and α1‐antitrypsin) were not significantly different between the strains, and the capacity of Kupffer cells isolated from infected mice of both strains to produce interleukin 1 (IL‐1) and tumor necrosis factor α (TNF‐α) was of the same degree. Thereafter, only DBA/2 Kupffer cells were able to produce membrane‐associated IL‐1 (ma IL‐1) as well as TNF‐α. Moreover, only DBA/2 splenocytes were able to produce interferon γ (IFN‐γ) upon stimulation withSalmonellaantigens, although concanavalin A‐stimulated splenocytes of both strains produced the same level of interleukin 2. Furthermore, administration of recombinant murine IFN‐γ and DBA/2 Kupffer cells of day 6 to BALB/c mice 3 days after infection resulted in a significant level of protection, whereas neither of these materials alone induced protection. Injection of anti‐TNF‐α antibodies did not affect the resistance of DBA/2 mice. Thus, these findings suggest that the early resistance ofItyrmice is partly attributable to their capacity to produce IFN‐γ and ma IL‐1 after infection.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.244

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractAlveolar macrophages (Am⊘s), resident peritoneal macrophages (RPm⊘s), and thioglycolate‐elicited peritoneal macrophages (TGPm⊘s) were isolated from C57BL/6 mice and incubated with lipopolysaccharide (LPS), stimulated cell supernatant, or recombinant interferon γ (IFN‐γ) for 24 h. Tumor necrosis factor (TNF) in cell‐free supernatants was measured by enzyme‐linked immunosorbent assay. Anio⊘s incubated with 103ng/ml LPS produced 50 times more TNF than RPm⊘s and 5 times more than TGPm⊘s, and LPS alone induced maximum TNF production by Am⊘s. Stimulated cell supernatant or recombinant IFN‐γ alone did not induce TNF production. A combination of LPS with stimulated cell supernatant or IFN‐γ had only a limited synergistic effect on TNF production by Am⊘s. However, both LPS and stimulated cell supernatant or recombinant IFN‐γ induced maximum TNF production by RPm⊘s and TGPm⊘s. TGPm⊘s showed greater sensitivity to LPS and stimulated cell supernatant or IFN‐γ with regard to TNF production than the other macrophage populations investigated.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.251

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study delineates the regulatory effects of inflammatory cytokines on mononuclear phagocyte plasminogen activator (PA) activity. The mechanisms by which mononuclear phagocytes modulate PA activity are described. Mononuclear phagocytes regulate net PA activity by the balanced expression of urokinase‐type PA (uPA), in either secreted or membrane‐associated forms, and a specific plasminogen activator inhibitor, PAI‐2. Therefore, understanding how immunomodulators regulate macrophage PA activity requires that the comparative effects of uPA and PAI‐2 be elucidated. We determined how recombinant interferon‐γ (IFN) and tumor necrosis factor‐α (TNF) regulate plasminogen activation in monoblast‐like U937 cells and normal human monocytes. In U937 cells, both IFN and TNF induced concurrent increases in secreted PA and PA inhibitor activities. These effects were accompanied by increased immunoreactive uPA and PAI‐2 in conditioned media (enzyme‐linked immunosorbent assay) and steady‐state levels of cellular uPA and PAI‐2 mRNA (Northern analysis). To determine the relative abilities of IFN and TNF to either promote or inhibit plasmin generation, we directly compared the effects IFN and TNF, using optimal stimulating concentrations. IFN induced PA activity to 180% of the level achieved by TNF. In contrast, IFN elicited only 78% of the PA inhibitor produced by TNF stimulation. These differences in secreted activity can be explained by the shift in balance between uPA and PAI‐2 proteins. Immunoreactive uPA was induced equally by IFN and TNF, but TNF generated higher levels of PAI‐2. The same overall pattern of results was seen in normal human monocytes. IFN and TNF differ greatly in the ability to augment receptor‐bound PA activity in U937 cells, as IFN induced a twofold increase but TNF had no effect. We conclude that IFN and TNF modulate mononuclear phagocyte proteolytic activity through coordinate regulation of secreted and receptor‐bound uPA, balanced against concurrent expression of PAI‐2. These effects are cytokine specific, as IFN is superior to TNF in stimulating expression of both secreted and receptor‐associated PA activities. These properties suggest mechanisms by which mononuclear phagocytes control proteolysis in cytokinerich inflammatory foci.

ISSN:0741-5400    

DOI:10.1002/jlb.51.3.256

出版商:Wiley    

年代:1992

数据来源: WILEY