Biomedical subjects

J J Finlay-Jones

Publications and source records attributed to J J Finlay-Jones.

At least 55 records · Page 3Linked to original sources

PubMed1995

Comparison of the suppressive effects of interleukin-10 and interleukin-4 on synovial fluid macrophages and blood monocytes from patients with inflammatory arthritis.

This study determined the potential capacity of interleukin-10 (IL-10), compared with IL-4, to control the production of tumour necrosis factor-alpha (TNF-alpha), IL-1 beta and IL-1 receptor antagonist (IL-1ra) and the expression of major histocompatibility complex (MHC) class II antigens by monocytes/macrophages isolated from synovial fluid of patients with rheumatoid or other forms of chronic inflammatory arthritis. Mononuclear cells were isolated from synovial fluid and peripheral blood and incubated with or without lipopolysaccharide (LPS), and with or without IL-10 (100 U/ml, 10 ng/ml) or IL-4 (10 ng/ml) for 22 hr. TNF-alpha, IL-1 beta and IL-1ra levels were measured by enzyme-linked immunosorbent assay (ELISA) in the culture supernatants, and MHC class II expression was examined on the monocytes/macrophages by flow cytometry. IL-10, unlike IL-4, decreased TNF-alpha production by LPS-stimulated synovial fluid cells to the same extent as by LPS-stimulated peripheral blood cells from the same patients. IL-10 and IL-4 suppressed equally IL-1 beta production by the same cells. However, only IL-4 significantly increased IL-1ra production by synovial fluid mononuclear cells. Synovial fluid cells expressed increased levels of MHC class II antigen, and these levels were not as efficiently suppressed by IL-10 as they were for peripheral blood cells. Because IL-10 and IL-4 differentially regulate TNF-alpha and IL-1ra production by synovial fluid mononuclear cells, selective use of either IL-10 or IL-4 in the treatment of chronic inflammatory conditions will depend on whether TNF-alpha or IL-1, respectively, is established as primarily responsible for the maintenance of the chronic inflammatory condition.

Arthritis↗

PubMed1993

Synovial fluid macrophages and blood monocytes differ in their response to IL-4.

IL-4 has been described as a potential anti-inflammatory molecule because of its ability in vitro to down-regulate human monocyte production of proinflammatory mediators. In this study, the activity of IL-4 on mononuclear cells and CD14+ macrophages from a site of chronic inflammation, namely, the joints of patients with rheumatoid and psoriatic arthritis, was investigated and compared directly with its activity on PBMC and monocytes from the same patients. In contrast to the response by blood monocytes, the response to IL-4 by synovial fluid cells was selective; IL-4 did not significantly suppress LPS-induced TNF-alpha production, but decreased CD14 expression to a similar extent in the two cell populations. IL-4 induction of monocyte/macrophage CD23 expression was investigated as a stimulatory response to IL-4, and although significantly increased on synovial fluid CD14+ cells by IL-4, the induction was considerably reduced compared with that measured for blood cells. Activation and differentiation in vitro of blood monocytes reduced their response to IL-4 for decreased TNF-alpha production and induction of CD23 and suggested that these biologic phenomena may contribute to the decreased responsiveness to IL-4 by synovial fluid monocytes/macrophages. Thus, IL-4 does not have the same anti-inflammatory properties in vitro on synovial fluid cells as on blood monocytes.

Antigens, CD↗

PubMed1993

Cis-urocanic acid stimulates human peripheral blood monocyte prostaglandin E2 production and suppresses indirectly tumor necrosis factor-alpha levels.

Photoisomerization of trans-urocanic acid (UCA) in the stratum corneum has been implicated in the immunosuppression detected after irradiation with UVB (UV wavelength of 280-320 nm). In this study, cis-urocanic acid suppressed human monocyte production of TNF-alpha by a PGE2-dependent mechanism. This contrasted with the mechanism involving histamine type 2 receptors by which the UCA structural analogue, histamine, suppressed monocyte TNF-alpha production. Histamine type 1 receptor antagonists were without effect on both the cis-UCA- and histamine-induced suppression of monocyte TNF-alpha levels. As indomethacin can reverse UVB-immunosuppression in murine models, we may have identified one of the cellular mechanisms responsible for reduced delayed-type hypersensitivity responses. Decreased TNF-alpha levels, by restricting further cytokine recruitment, may also limit the development of the inflammatory components of hypersensitivity responses.

Brompheniramine↗

PubMed1993

Inflammatory fluids regulate TNF-alpha, but not IL-1 beta, production by human peritoneal macrophages. A study of patients on continuous ambulatory peritoneal dialysis with peritonitis.

To gain insight into the factors regulating an inflammatory response in vivo, the activities of peritoneal macrophages and the influence of the inflammatory fluids from which they were harvested were studied in continuous ambulatory peritoneal dialysis (CAPD) patients with peritonitis. Specifically, the production of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and prostaglandin E2 (PGE2) by lipopolysaccharide-stimulated human peritoneal macrophages from CAPD patients with peritonitis was examined in the presence of the inflammatory dialysates from which they were isolated. When tested at a dilution of 20%, the dialysates inhibited production of TNF-alpha, a key monokine in the orchestration of the inflammatory response. In contrast to the effect on TNF-alpha, the dialysates did not affect IL-1 beta production by stimulated macrophages. The activity inhibitory for TNF-alpha synthesis was not fully characterized, but a number of known inhibitors were shown not to be responsible for the suppressive activity. The inhibitory activity was detected in cases of noninfective peritonitis and excluded the possibility that a bacterial product was responsible. Hyperosmolality, pH, protein levels, glucose, uremic molecules, cortisol, heparin, and antibiotics were not responsible for the inhibitory activity. The activity had some similarity to the reported actions of alpha-globulins (which are acute phase proteins), PGE2, TNF-alpha soluble receptors, and IL-6, but there was no evidence for their involvement. Whether the selective suppression of TNF-alpha production is a general finding in inflammatory responses will require additional studies. This study nevertheless illustrates the potential for the host to regulate tightly the development of an excessive inflammatory response and thus to limit tissue pathology. However, it is unknown whether an appropriate host defense is compromised.

Acute-Phase Proteins↗

PubMed1993

Reduced secretion of IL-1 beta by peritoneal cells from patients on continuous ambulatory peritoneal dialysis.

The endogenous and lipopolysaccharide stimulated interleukin (IL)-1 beta production in vitro by peritoneal monocytes/macrophages from patients on continuous ambulatory peritoneal dialysis (CAPD) was examined during episodes of infection and inflammation. Measurement of immunoreactive IL-1 beta and bioactive IL-1 in both supernatants and cell lysates after culture for 18 h revealed that these cells secreted a significantly lower proportion of total IL-1 than that measured for elutriated blood monocytes. For the inflammatory peritoneal cells, the proportion of total IL-1 beta that was cell-associated resembled that reported for more differentiated pulmonary alveolar macrophages and for adherent monocytes cultured for 18 h prior to stimulation. A similar reduced ability to secrete IL-1 beta was detected for unfractionated peritoneal cells from CAPD patients without peritonitis upon direct comparison with the IL-1 beta production by blood mononuclear cells from the same patients. These results suggested that at a time when a pro-inflammatory response by extravasated host monocytes/macrophages was required by CAPD patients with peritonitis, only a minor proportion of total IL-1 beta would be available extracellularly. This study highlights the rapidity with which extravasated monocytes lose their ability to secrete IL-1 beta and raises the possibility that an important site of utilization of IL-1 beta in vivo may be intracellular in its location.

Humans↗

PubMed1993

The effects of RU 41.740, a glycoprotein immunomodulating agent derived from Klebsiella pneumoniae, on intra-abdominal abscess formation in mice.

The prophylactic and therapeutic efficacies of the immunomodulating agent RU 41.740 (a glycoprotein extract from Klebsiella pneumoniae) were studied in a murine model of intra-abdominal abscess formation with Bacteroides fragilis, Escherichia coli, and bran as an abscess-potentiating agent. Parenteral injection of RU 41.740, either before or after injection of an abscess-inducing mixture (AIM), was associated with significantly diminished incidence and size of abscesses. Abscess incidence and size were significantly decreased by oral administration of RU 41.740 after, but not before, AIM injection. Abscess formation and resolution are the results of complex interactions of host defence mechanisms with bacteria and potentiating agent, and RU 41.740 has been shown previously to activate both macrophage and neutrophil function. These results indicate that activation of non-specific defences may protect against abscess development in chronic sepsis.

Abdomen↗

PubMed1993

The effect of cytokines on bactericidal activity of murine neutrophils.

A range of recombinant cytokines have now been shown to modify aspects of the phenotype and function of human and murine neutrophils. However, few reports describe modification of the bactericidal activity of neutrophils. We therefore examined the recombinant murine cytokines tumor necrosis factor-alpha (TNF-alpha, 10-1000 ng ml-1) and granulocyte macrophage-colony stimulating factor (GM-CSF, 10-1000 U ml-1) for their ability to increase the bacterial killing capacity of murine neutrophils. Neutrophils from either bone marrow (fresh or cultured), or peritoneal exudates, or abscesses, were pre-incubated with either cytokine for 30-60 min and the killing of Proteus mirabilis, Escherichia coli, or Bacteroides fragilis was examined in the presence or absence of serum over a 90 min period. Only for one combination was a small but significantly enhanced level of bacterial killing observed, the phagocytic killing of P. mirabilis by peritoneal exudate neutrophils in the presence of GM-CSF and serum. With this exception there was no enhancement of bacterial killing for the range of combinations of neutrophils and bacterial species tested. In contrast, at the concentrations tested for effect on bactericidal activity, TNF-alpha and GM-CSF were able to significantly upregulate CR3 (but not Fc gamma RII) expression on mouse neutrophils. These results indicate that upregulation of CR3 as an index of neutrophil activation does not necessarily correlate with increased bactericidal activity.

Animals↗

PubMed1992

Peritoneal macrophages during peritonitis. Phenotypic studies.

The expression of a range of surface molecules/receptors that are important in the host response to infection and foreign antigens was examined using peritoneal macrophages isolated from patients on continuous ambulatory peritoneal dialysis (CAPD) with peritonitis. The macrophage phenotypic profile was compared with that of normal peripheral blood monocytes. Consistently there was increased expression by macrophages of CD14, ICAM-1 (CD54), Fc gamma RI (CD64), Fc gamma RII (CDw32), Fc gamma RIII (CD16), transferrin receptors (CD71) and tissue factor. Increased expression of MHC class II was marginally significant. There was no detectable expression of either the p55 (CD25) or p70 chains of the IL-2 receptor. The expression of the complement receptors, CR1 (CD35) and CR3 (CD11b, CD18), was reduced. The activity of well-known inflammatory cytokines, rather than uraemic molecules, can account for the phenotypic profile of these extravasated peritoneal macrophages. The results of this study indicate that peritoneal macrophages from CAPD patients with peritonitis display a phenotype consistent with them being in vivo-derived inflammatory macrophages, and that they are appropriate for use in studies of anti-inflammatory agents.

Antigens, CD↗

PubMed1992

Interleukin-4 suppression of monocyte tumour necrosis factor-alpha production. Dependence on protein synthesis but not on cyclic AMP production.

The molecular mechanisms by which human interleukin-4 (IL-4) down-regulates tumour necrosis factor-alpha (TNF-alpha) production by monocytes remain unknown. Other studies of IL-4 action in B lymphocytes and large granular lymphocytes (LGL) suggested that IL-4 may suppress mediator production by augmenting intracellular cyclic AMP (cAMP) levels. However, this study did not find evidence for involvement of a cAMP-dependent signalling pathway for expression of IL-4 activity in monocytes. IL-4 reduced TNF-alpha production by monocytes when IL-4 and lipopolysaccharide (LPS) were added concomitantly, or upon subsequent activation by LPS 16 hr after first exposure to IL-4. The continued presence of IL-4 at the time of LPS stimulation was not necessary; however, the suppressive effects of IL-4 were dependent on protein synthesis. This sustained activity of IL-4 for down-regulation of the production of inflammatory signals may be important for control in vivo of excessively activated monocytes/macrophages, and in therapy.

Cells, Cultured↗

PubMed1991

Pathogenesis of intraabdominal abscess formation: abscess-potentiating agents and inhibition of complement-dependent opsonization of abscess-inducing bacteria.

Bacteroides fragilis and Escherichia coli are synergistic in the production of intraabdominal abscesses. However, these bacteria initiate abscess formation only when inoculated with an agent such as autoclaved colonic contents (ACC) or bran (a fiber analogue). The mechanism of action of the abscess-potentiating agent was studied. Opsonins in normal mouse serum were determined for phagocytic killing by murine neutrophils of B. fragilis and E. coli. Opsonization required fixation of complement by the alternative pathway. ACC (0.2 mg/ml) and bran (1.0 mg/ml) inhibited phagocytic killing of Proteus mirabilis in the presence of normal but not immune serum. Assay of the alternative pathway of complement activation indicated that both bacterial components and abscess-potentiating agents in an abscess-inducing mixture activated complement. These findings suggest that abscess-potentiating agents inhibit opsonization and therefore the subsequent phagocytic killing of bacteria in the nonimmune host.

Abscess↗

PubMed1991

Bacterial killing in vitro by abscess-derived neutrophils.

In the absence of antimicrobial therapy, bacteria such as Bacteriodes fragilis, Escherichia coli and Proteus mirabilis may persist within an intra-abdominal abscess in the presence of large numbers of neutrophils which, under optimal conditions in vitro, can readily phagocytose and kill the same bacterial strains. Neutrophils taken from abscesses induced by gram-negative bacteria such as those above contain viable organisms. On incubation in vitro in the presence of serum, these neutrophils kill the bacteria phagocytosed in the abscess poorly, if at all, yet can readily kill organisms added in vitro. To determine possible mechanisms that might explain this, we examined the bactericidal activity in vitro of neutrophils from a range of abscesses induced by one or two species of bacteria plus an abscess-potentiating agent, bran. The organisms studied were B. fragilis, E. coli, P. mirabilis and Staphylococcus aureus. The killing in vitro of E. coli and P. mirabilis, engulfed within an abscess, was significantly less than that of the same organisms when they were added to the in-vitro assay. In contrast, the killing of S. aureus was similar, whether engulfed in vivo or in vitro. However, S. aureus was less susceptible to phagocytosis and killing in vitro than P. mirabilis or E. coli, and the killing of S. aureus during in-vitro incubation of neutrophils that had engulfed the organism with in the abscess was similar to that of the gram-negative bacteria engulfed within the abscess.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗

PubMed1991

IL-4 suppresses IL-1 beta, TNF-alpha and PGE2 production by human peritoneal macrophages.

Human interleukin-4 (IL-4) down-regulates IL-1 and tumour necrosis factor-alpha (TNF-alpha) production by monocytes stimulated in vitro. In contrast, in studies of activation of murine macrophages, both stimulatory and inhibitory functions of murine IL-4 have been documented. To investigate whether opposing activities of IL-4 reflect a difference in the target cell studied, due either to cell maturation or the site from which the cells were isolated, we examined the effect of IL-4 on human peritoneal macrophage production of IL-1 beta, TNF-alpha and prostaglandin E2 (PGE2). Human peritoneal macrophages stimulated with lipopolysaccharide (LPS) produced levels of these mediators that were at least as great as those previously reported for monocytes. Similarly, IL-4 was inhibitory for peritoneal macrophage mediator production after in vitro stimulation. Thus, IL-4 has effects on human peritoneal macrophages similar to those on blood monocytes. In addition, as it down-regulates mediator production by cells that have left the circulation, it may be important in controlling the immune response in tissues.

Ascitic Fluid↗

PubMed1990

Functional activity of individual abscess neutrophils from mice.

In the absence of antibiotic therapy, viable bacteria can persist within intra-abdominal abscesses in mice for at least 10 weeks. The mechanisms contributing to this survival are unknown, but abscess-derived neutrophils have impaired abilities to kill, in vitro, organisms engulfed in vivo. In order to determine whether subpopulations of abscess neutrophils might be discernible on the basis of phenotypic or functional criteria, cells from murine intra-abdominal abscesses were examined for phagocytic activity, CR3 expression, and H2O2 production in response to soluble and particulate stimuli. With respect to phagocytosis of Proteus mirabilis, abscess cells were no less efficient than peritoneal exudate neutrophils; no significant subpopulation of cells was incapable of phagocytosis in the presence of normal mouse serum. Using flow cytometry to examine abscess neutrophils for CR3 expression, we found that no subpopulations of cells were observed with unstimulated cells or with cells incubated with either phorbol 12-myristate 13-acetate or bacteria and serum. Intracellular H2O2 levels were measured by using the probe 2',7'-dichlorofluorescin diacetate. In general, incubation with phorbol 12-myristate 13-acetate resulted in similar increases in H2O2 production in all cells of the population. However, stimulation with bacteria and serum revealed a variable but consistent, poorly responsive subpopulation of neutrophils in abscess cell populations. Cell-sorting experiments showed that cells from the poorly responsive section of the FACS profile contained significantly higher numbers of abscess-derived bacteria, suggesting the presence of a subpopulation of viable abscess neutrophils harboring persisting viable bacteria.

Abscess↗

PubMed1990

Detection of cytokine mRNA in astrocyte cultures using the polymerase chain reaction.

To clarify which cytokines could potentially be produced by astrocytes, we have assessed the presence of mRNA for a number of cytokines in astrocyte-enriched brain cultures. The cultures were derived from neonatal murine brain and were treated with either interferon-gamma, lipopolysaccharide or tumor necrosis factor-alpha, or infected with murine cytomegalovirus. RNA was extracted at 0, 4, 24 and 48 hours post treatment. A DNA copy of total cytoplasmic RNA was synthesised and specific cDNA amplified using the polymerase chain reaction and detected by hybridization with specific probes. The following cytokines were studied: IL3, IL4, IL6, TNF alpha, TGF beta, LIF, G-CSF, M-CSF and GM-CSF. Transcripts for TGF beta, IL6, LIF and M-CSF were present constitutively but increased with stimulation, whereas transcripts for TNF alpha, IL6, GM-CSF, G-CSF and LIF were detected only after stimulation. Messenger RNA for IL3 and IL4 was not detected. The magnitude and kinetics of the induction varied according to the cytokine and the stimulus. These results indicate the possibility of intra-cerebral production of a number of cytokines that may play a role in the clearance of viral or bacterial pathogens and in the generation of neuropathology.

Animals↗

PubMed1989

Differences in the phenotypes of cells mediating anti-tumour immunity at various stages of tumour progression in mice.

In Winn assays, T cells from donors immunized by tumour excision, or from mice with small tumours, mediate rejection of the metastasizing murine fibrosarcoma MC-2. As the mean size of primary tumours in spleen donors increases, the strength of anti-tumour activity declines, until it is frequently undetectable in spleen cells from mice with very large tumour burdens. Loss of splenic anti-tumour activity is coincident with the appearance of cells capable of suppressing an otherwise protective anti-tumour response in Winn assays. This paper defines the phenotypes of T cells mediating immunity against MC-2. Eleven or more days after tumour inoculation the proportions of tumour-bearer splenic leucocytes expressing Ly 1.2 (CD5), Ly 2.2 (CD8a) or L3T4 (CD4) surface antigens were significantly less than similar preparations from normal animals. Depletion of Ly 1.2+ or L3T4+ cells from spleen cells of donors with small tumours, or from donors immunized by tumour excision, diminished protection in the Winn assay. Depletion of Ly 2.2+ cells from these donors had no effect on immunity. In contrast, spleen cells taken from donors with large tumors lost all anti-tumour activity if pretreated with any one of anti-Ly 1.2 or anti-Ly 2.2 or anti-L3T4 antibodies in the presence of complement. These results suggest that cells bearing the Ly 2.2 marker may be important to weak immunity remaining in the spleens of mice with large tumours, but are not critical to strong immunity generated early in tumour growth, nor to that following tumour excision. That is, in addition to an Ly 1.2+, Ly 2.2-, L3T4+ spleen cell subset also seen early in the growth of the MC-2 tumour, a cell population which expresses the Ly 2.2 marker and which is important to anti-tumour immunity emerges late in tumour growth.

Animals↗

PubMed1988

Analysis of C3 deposition and degradation on bacterial surfaces after opsonization.

C3b and iC3b, opsonic fragments of C3, interact with specific receptors on phagocytic cells. After bacterial opsonization, C3 fragments were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, western blotting, and immunodetection. For bacteria opsonized in 50% pooled human serum (PHS), C3 deposition and cleavage to iC3b occurred rapidly. C3b, iC3b, and C3d made up 17%, 64%, and 19%, respectively, of the C3 on Staphylococcus aureus and 53%, 44%, and 2% respectively, on Escherichia coli. Residual C3b was refractory to factor I cleavage, an occurrence enabling alternative pathway activation to continue. C3 deposited was quantitated by enzyme-linked immunosorbent assay; with 50% PHS, greater than 50% and 90% of total C3 deposition occurred within 5 and 10 min, respectively. With a lower percentage of PHS, maximal deposition required up to 60 min and was not achieved in less than 10% PHS. Ester-bound fragments represented 34% and 82% of covalently bound C3 on S. aureus and E. coli, respectively.

Amides↗

PubMed1987

Functional neutrophils from long-term murine bone marrow cell cultures.

Murine bone marrow cell cultures that had been established for up to 26 weeks were harvested each week and found to provide functional neutrophils. Leukocytes harvested from the cultures were enriched for neutrophils using discontinuous Percoll density gradients. These cells mounted a chemiluminescence response to Proteus mirabilis in the presence of normal mouse serum (NMS). They killed several NMS-opsonised bacterial species, an activity that was blocked by a monoclonal antibody to the C3 receptor of mouse neutrophils. Cultured bone marrow neutrophils expressed both Fc and C3 receptors. C3 receptor expression could be augmented by exposure to the chemotactic peptide f-Met-Leu-Phe. We conclude that murine bone marrow cell cultures provide a useful source of functional neutrophils, and that their productivity can be sustained in long-term culture. As their receptor expression can be augmented from the resting state by exogenous stimuli, they represent a useful cell source in studies of neutrophil activation.

Animals↗

PubMed1987

Roles of antibody and complement in the bactericidal activity of mouse peritoneal exudate neutrophils.

The contributions of complement and antibody to phagocytosis and, as a separate process, intracellular killing of Proteus mirabilis, were investigated using mouse peritoneal exudate neutrophils. Phagocytosis of P. mirabilis was promoted by both immune mouse (IMS) and normal mouse (NMS) sera. Opsonization by IMS promoted significantly greater phagocytosis than did NMS, as did NMS compared with heated IMS (HIMS). The ability of NMS to opsonize P. mirabilis for both phagocytosis and phagocytic killing was diminished by chelation with EGTA and abolished by chelation with EDTA. This suggested that fixation of complement by both alternative and classical pathways provided optimal opsonization of this organism in NMS. In order to study intracellular killing as a process separate from phagocytosis, peritoneal exudate cell suspensions were exposed to P. mirabilis, previously incubated with 1% NMS, 1% IMS, 10% HNMS (heated normal mouse serum) or 10% HIMS, followed by centrifugation of the phagocyte-bacteria mixtures on Percoll density gradients. Populations of neutrophils containing viable intracellular bacteria, and relatively free of extracellular bacteria (less than 7% of total) were recovered in washed suspensions of cells fractionated at densities greater than 1.069 g/ml. For P. mirabilis that had been opsonized with 1% NMS before phagocytosis, the continued presence of extracellular serum was necessary for intracellular killing. NMS stimulated significantly greater intracellular killing than did HNMS, which stimulated some intracellular killing compared with the absence of serum, in which no killing occurred. IMS was similar to NMS in its ability to stimulate intracellular killing. EGTA partially blocked the stimulation of intracellular killing by NMS, and EDTA abolished it. These findings suggested that (as for optimal opsonization) complement activated via both alternative and classical pathways was responsible for optimal stimulation of intracellular killing.

Animals↗