摘要:

AbstractIn 1965 Wheelock reported that phytohemagglutinin could induce from human leukocytes an interferon‐like virus inhibitor [1]. This substance, which turned out to be interferon‐γ (IFN‐γ), has been the subject, directly or indirectly, of thousands of scientific publications since that initial report. Past research has led to the general conclusion that IFN‐γ is much more than an interferon in that it has broader effects on the various arms of the immune system than most any other lymphokine or cytokine. In this review we discuss the effects of IFN‐γ on the various cell lineages of the immune system, focusing on the biology of its actions. In addition, we summarize research focused on the consequences of introducing IFN‐γ cDNA into tumor cells, aberrant IFN‐γ production in transgenic animals, and inhibition of IFN‐γ effects by knocking out either the IFN‐γ gene itself or the IFN‐γ receptor gene.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.373

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractNatural resistance to infection with intracellular parasites is controlled in the mouse by the expression of a locus or group of loci on chromosome 1 alternatively namedBcg, Lsh, andIty. Bcgaffects the capacity of mature tissue macrophages to restrict the intracellular proliferation of ingested parasites in the reticuloendothelial organs of the host during the early phase of infection. This review summarizes our molecular genetic approach to the isolation and characterization of theBcglocus. We have used a positional cloning strategy based on genetic and physical mapping, YAC cloning, and exon trapping to isolate a candidate gene forBcg, namedNramp1, which codes for a macrophage‐specific polytopic protein with 12 predicted transmembrane domains and a consensus transport motif. Sequence analysis ofNramp1cDNA clones from 27BcgrandBcgrmouse strains reveals that susceptibility to infection (Bcgr) is associated with a single nonconservative Gly to Asp substitution at position 169 within predicted transmembrane domain 4 of the Nramp protein. Cloning experiments and homology search in available databases demonstrated that theNramp1gene belongs to a small gene family with several members in vertebrates and in such distantly related species as yeast and plants. Nramp proteins share a remarkable degree of similarity, with strong amino acid sequence conservation in the transmembrane domains, suggesting a common transport function for the Nramp family. Finally, we generatedNramp1−/‐gene knockout mice, and analysis of their phenotypic characteristics established that (1)Nramp1plays a key role in natural defense against infection with intracellular parasites and therefore demonstrated allelism betweenNramp1andBcg/Ity/Lsh, (2) Nramp1 functions by a novel cytocidal/cytostatic mechanism distinct from those expressed by the activated macrophage, and (3) theNramp1Asp169allele ofBcgrinbred strains is a null allele, pointing to a critical role of this residue in Nramp1 function.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.382

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractA role for nitric oxide (NO) in the regulation of blood leukocyte numbers was examined in BALB/c mice by employing the NO synthase inhibitor NG‐nitro L‐arginine methyl ester (L‐NAME). Treatment of animals with a single dose of 50 mg/kg body wt caused a dramatic increase in the number of circulating neutrophils and a moderate decrease in the number of circulating lymphocytes. These effects were partially reversed by the simultaneous inoculation of L‐arginine (250 mg/kg body wt.) but not by D‐arginine. A second NO synthase inhibitor, NG‐nitro L‐arginine, induced changes comparable to those elicited by L‐NAME. Because catecholamines and glucocorticoids are well‐known modulators of blood leukocyte counts, experiments were carried out in adrenalectomized mice. It was found that adrenalectomy did not modify the increase in the number of circulating neutrophils induced by L‐NAME but completely prevented the decrease of circulating lymphocytes. Taken together, these findings support the hypothesis that NO plays an important role in the regulation of the peripheral blood number of neutrophils and lymphocytes, and that this function involves, in each case, the participation of different mechanisms.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.391

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractEosinophils are supposed to play a critical role in the pathology of several allergic diseases because after activation they can release toxic and proinflammatory agents. In this study we have investigated whether IgE‐mediated rat pleurisy could be affected by an ongoing pleural eosinophilic inflammatory response. IgE‐passively sensitized rats were challenged with an intrapleural (i.pl.) injection of allergen (dinitrophenylated bovine serum albumin, 1 μg/cavity) and exudation assessed by measuring the amount of protein extravasated into the pleural cavity within 4 h. We have confirmed that lipopolysaccharide (LPS) stimulation (250 ng/cavity i.pl.) was followed by a marked pleural neutrophilia, apparent at 3 h, which was followed by an eosinophil accumulation noted within 48–72 h postchallenge. We have also confirmed that a boiled sample of LPS pleural washing (IPS‐PW, 200 μl i.pl.) caused selective eosinophilia in recipient rats. Pleural exudation remained unaltered when the allergenic challenge was performed 3 h after IPS in a condition of intense pleural fluid neutrophilia. In contrast, this was significantly reduced (P<.001) when the challenge occurred 72 h after IPS or 24 h after IPS‐PW in selective pleural fluid eosinophilia. In another series of experiments repeated daily i.pl. injections of platelet‐activating factor (PAF; 1 μg/cavity) resulted in a progressive increase in eosinophil number recovered from the pleural cavity. The values were 1.2 ± 0.2, 3.0 ± 0.2, and 5.8 ± 0.5 × 106eosinophils/cavity (mean±SEM) after 0, 1, and 4 injections, respectively. Allergen challenge performed after 0, 1, or 4 PAF stimulations led to pleural protein levels of 88.6 ± 5.7, 33.7 ± 0.7, and 19.4 ± 2.3 mg/cavity, respectively, indicating that the allergic pleurisy is inhibited in a manner dependent on the magnitude of eosinophil accumulation. Furthermore, the impairment of PAF‐induced eosinophil accumulation by cetirizine (30 mg/kg i.p.) restored the exudatory response. Exudation triggered by compound 48/80 (25 μg/cavity), histamine (200 μg/cavity), or 5‐hydroxytryptamine (100 μg/cavity) was not affected by four previous PAF daily injections. The findings indicate that allergen‐induced exudation is selectively down‐regulated in the eosinophil‐enriched pleural space of rats, a suppression that increased with increasing eosinophil number and disappeared after chemical impairment of the eosinophilia.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.395

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractLigand‐induced cross‐linking of Fcγ receptors (FcγR) on neutrophils plays a significant role in their stimulation, shown here by contrasting the responses induced by low valency immune complexes (LICs) and high valency immune complexes (HICs) and by cross‐linking LICs in situ (L/Ab) after their addition to the cells. Multiparameter flow cytometry was used to measure immune complex (IC)‐elicited changes in cytoplasmic Ca2+concentration and initiation of the oxidative burst simultaneously in the same cell and to correlate these with FcγR occupancy. We have previously shown that subpopulations of neutrophils respond maximally to subsaturating concentrations of HIC; saturating dosages stimulate the entire population. This discrepancy was not due to differences in receptor occupancy. The magnitude of the transient Ca2+increase was independent of the dose of HIC but depended on the dose when an LIC was used. As shown here, L/Ab cross‐linking elicited Ca2+responses similar to those observed in HIC‐stimulated cells. In contrast, LIC elicited only minimal intracellular ΔpH and no oxidative burst or membrane potential changes at all unless FcγR was cross‐linked, accomplished by HIC or by L/Ab. However, azurophilic degranulation, as determined by elastase release, was not observed in cells stimulated by the in situ cross‐linking method, whereas the HIC preparation triggered azurophilic degranulation. Thus, some FcγR‐mediated neutrophil effector functions such as azurophilic degranulation and oxidative burst initiation have an absolute requirement for FcγR cross‐linking, whereas signaling functions such as changes in membrane potential, intracellular pH, and intracellular Ca2+concentration can occur, albeit more slowly and to a lesser extent, if single FcγR are occupied.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.403

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo Fcγ receptor (FcγR) subclasses on human neutrophils, FcγRII and FcγRIII, activate different cellular functions. To examine the involvement of each receptor subtype in polymorphonuclear leukocyte activation, Fab and F(ab')2 fragments of subclass‐specific monoclonal antibodies ([mAbs] mAb IV.3 against FcγRII and mAb 3G8 against FcγRIII, respectively) were used to block the binding of low valency immune complexes (LICs) and high valency immune complexes (HICs). Flow cytometry then permitted the simultaneous quantitation of antibody and ligand binding, the elicited intracellular Ca2+concentration (Δ[Ca2+]int), initiation of the oxidative burst, and/or the phospholipase A activation in the same cell. We have previously demonstrated that subsaturating dosages of HIC bind uniformly to all the cells but elicit an “all‐or‐none” (i.e., dose independent) maximal Δ[Ca2+]int in a dose‐dependent subpopulation of the cells. In contrast, both the proportion of cells responding and the magnitude of the Δ[Ca2+]inttransient depend on the subsaturating dose of LIC, even though it too binds uniformly to all the cells, nonresponding as well as responding. These earlier findings have here been extended by single cell flow cytometric analysis to demonstrate that F(ab')2FcγRIII is the major FcγR involved in HIC binding (and [Ca2+]intmobilization), as well as in oxidative burst and phospholipase A activation. In contrast, both receptor subclasses must be available for LIC‐elicited Δ[Ca2+]int, as blockage by either of the mAb Fab or F(ab')2fragments abrogates this response, even though LIC binding to the receptors is not decreased. Furthermore, LIC elicited little oxidative burst activity and failed to activate phospholipase A but cross‐linking to achieve multivalency, previously shown to induce [Ca2+]intand oxidative burst responses, elicited phospholipase A activity via FcγRIII. FcγRII's role appears to be modulation of the small, late Ca2+influx observed at>1 min, whereas FcγRIII modulates all the earlier larger events. Thus, simultaneous observation of receptor identity, receptor occupancy, and consequent activation parameters in the same cell by flow cytometry permits use to demonstrate that FcγRII is necessary for the small signal transduction elicited by LIC; it plays a relatively small role in polymorphonuclear leukocyte stimulation by HIC. FcγRIII is the main receptor responsible for immune complex‐elicited polymorphonuclear leukocyte responses; its efficacy is greatly enhanced when the receptors are cross‐linked, either by preequilibrated multivalent complexes or by in situ cross‐linking of bound LIC with excess antibody.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.415

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractAs a model for lymphokine‐activated killer (LAK) function in HIV infection, we studied LAK cells in cats infected with feline immunodeficiency virus (FIV), which causes an acquired immunodeficiency syndrome. Peripheral blood mononuclear cells cultured in concanavalin A and interleukin‐2 developed LAK cytotoxicity against chronically FIV‐infected CrFK cells and acutely infected CD4+lymphocytes but not uninfected cells. LAK cells from FIV+cats were more cytotoxic than LAK cells from uninfected cats. Enhanced FIV+LAK cytotoxicity against feline leukemia virus–infected cells (FL74) suggested that the cytotoxicity was not antigen specific. Two‐color fluorescence‐activated cell sorter analysis and antibody depletion studies demonstrated that the majority of LAK cells and their progenitors were positive for both CD8 and CD57. The in vitro induction of dual positive CD8+CD57+LAK cells was enhanced in FIV+cats, as reported for HIV+patients. These CD8+CD57+LAK cells may play a role in maintaining the long asymptomatic stage of infection in FIV+cats.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.423

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractColony‐stimulating factor‐1 (CSF‐1) is a hematopoietic growth factor that regulates the survival, proliferation, and differentiation of mononuclear phagocytes. Because this cellular compartment undergoes major changes during fetal and neonatal life, we examined concurrent CSF‐1 expression during human development. While levels increased dramatically after full‐term birth, CSF‐1 concentrations steadily declined in the preterm circulation from 2.7 to 1.9 times adult values as gestational age increased. CSF‐1 was already detectable at 10 weeks gestation in spleen, intestine, lung, kidney, heart, and liver in order of decreasing concentration, but a positive correlation with gestational age was seen only in lung and intestine. Although a 4.4‐kb CSF‐1 mRNA was detectable in all tissues at all gestational ages, increased expression with advancing gestational age was observed in lung and kidney, whereas a rise and fall was observed in spleen. We conclude that CSF‐1 concentration in the human circulation is developmentally regulated and that its expression in fetal tissues is compatible with its role in regulating the development of tissue mononuclear phagocytes.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.432

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractSoluble mediators and inducible cell‐surface and matrix‐bound molecules coordinate the cascade of events giving rise to leukocyte emigration. Knowledge of the specific mechanisms underlying the attraction of cells into a local site, however, remains sketchy. In particular, it is unclear how chemoattractants cause rapidly moving immune cells to adhere to the blood vessel wall and to enter tissues. Here we show that the neuroendocrine human growth hormone, a chemoattractant for monocytes and lymphocytes in vitro, promotes haptotaxis, the migration of the cells induced by surface‐bound gradients. Combination of soluble growth hormone with soluble attractants, RANTES or formyl peptide, deactivates the migratory responses, as do combinations of surface‐bound growth hormone with surface‐bound RANTES or formyl peptide. In contrast, exposure of mononuclear leukocytes to combinations of soluble chemotactic with surface‐bound haptotactic gradients of attractants does not deactivate migration. The findings suggest that growth hormone may act as haptotactic agent, on the one hand, and that soluble attractants do not appear to affect haptotaxis when acting in concert with a surface‐bound attractant, on the other. This observation may have implications for the differential regulation of leukocyte accumulation in the vessel wall at systemic and local sites.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.438

出版商:Wiley    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effect of histamine on the production of cytokines by subpopulations of mononuclear cells was studied. A 3.5‐fold increase in the number of myeloid colony‐forming units (CFU‐C) was observed when bone marrow cells were cultured in the presence of conditioned medium prepared from nonadherent mononuclear cells cultured with 10−4M histamine (CM‐histamine) compared with phosphate‐buffered saline (CM‐PBS). Using ELISA and radioimmunoassay kits, histamine was found to enhance the production of GM‐CSF (9.6‐fold) and IL‐6 (8.2‐fold) by mononuclear cells but not by nonadherent cells or large granular lymphocytes. Anti‐GM‐CSF and anti‐IL‐6 antibodies markedly blocked cytokine activity in CM‐PBS, whereas the blocking effect in CM‐histamine was moderate, indicating enhanced GM‐CSF and IL‐6 activity in CM‐histamine. No GM‐CSF or IL‐6 levels could be detected in CM‐histamine or CM‐PBS prepared from CD3+, CD4+, or CD8+lymphocytes. Preincubation of CM‐histamine with H1and H2receptor antagonists resulted in complete blocking of the histamine‐enhanced colony‐stimulating activity. We conclude that histamine is able to activate human mononuclear cells to generate cytokines such as GM‐CSF and IL‐6 via H1and H2receptors.

ISSN:0741-5400    

DOI:10.1002/jlb.58.4.445

出版商:Wiley    

年代:1995

数据来源: WILEY