In vitro generation of eosinophil chemotactic factor from human and murine mononuclear phagocytes

Eosinophil chemotactic factor in tumour tissue from a patient with Kimura's disease

An extract of tumour tissue from a patient with Kimura's disease was tested for eosinophil chemotactic activity using the Boyden chamber method. Eosinophil chemotactic activity was detected in the tissue extract, and after gel filtration maximum activity was found in the fraction with a molecular weight of approximately 1000 daltons. This factor may play a role in the tissue eosinophilia which occurs in Kimura's disease.

Acute tropical pulmonary eosinophilia. Characterization of the lower respiratory tract inflammation and its response to therapy

Although acute tropical pulmonary eosinophilia (TPE) is well recognized as a manifestation of filarial infection, the processes that mediate the abnormalities of the lung in TPE are unknown. To evaluate the hypothesis that the derangements of the lower respiratory tract in this disorder are mediated by inflammatory cells in the local milieu, we utilized bronchoalveolar lavage to evaluate affected individuals before and after therapy. Inflammatory cells recovered from the lower respiratory tract of individuals with acute, untreated TPE (n = 8) revealed a striking eosinophilic alveolitis, with marked elevations in both the proportion of eosinophils (TPE 54 +/- 5%; normal 2 +/- 5%; P less than 0.001) and the concentration of eosinophils in the recovered epithelial lining fluid (ELF) (TPE 63 +/- 20 X 10(3)/microliter; normal 0.3 +/- 0.1 X 10(3)/microliter; P less than 0.01). Importantly, when individuals (n = 5) with acute TPE were treated with diethylcarbamazine (DEC), there was a marked decrease of the lung eosinophils and concomitant increase in lung function. These observations are consistent with the concept that at least some of the abnormalities found in the lung in acute TPE are mediated by an eosinophil-dominated inflammatory process in the lower respiratory tract.

Generation and characterization of a neutrophil-derived inhibitor of fibroblast chemotaxis

During in vitro chemotaxis, human embryonic fibroblasts migrate toward the leukotriene B4 (LTB4) contained in ionophore-induced human mononuclear-cell supernatants, but they do not migrate toward the LTB4 contained in ionophore-induced neutrophil supernatants. We further analyzed and characterized this inhibitory effect. The inhibitor was found to be present in stimulated, but not in unstimulated, neutrophil supernatants. The inhibitor was also shown to be heat labile, to interfere with the chemotaxis of the tumor cell lines HT 1080 and L 929, and to be effective during chemotaxis stimulated by LTB4, conditioned medium, or fibronectin. At Sephadex-G-200 chromatography, the inhibitor eluted in a region corresponding to a molecular mass of 16,000 daltons. Preincubation experiments showed that its mechanism of action is not cell directed, and it had no effect on random migration, cell spreading, and cell attachment. Furthermore, the inhibitor does not interact with the binding of fibronectin to its specific antibody; thus, an interaction of the inhibitor with nonspecific sites which are common to several chemotactic factors must be postulated instead. The biological role of the inhibitor may be related to the regulation of cell migration during wound repair.

Production of LTB4-like chemotactic arachidonate metabolites from human keratinocytes

Keratinocytes have recently been recognized as a source of mediators of cellular immune function. We present here further data on the production of 5-lipoxygenase-dependent arachidonate metabolites from freshly isolated human epidermal cells. Stimulation of cells with arachidonic acid or the calcium ionophore A 23187 alone or together caused a dose- and time-dependent release of chemotactic activity which was maximal during the first 10 min and which continued for up to 18 h. Indomethacin (10(-6) M) enhanced and compound BW 755C (20 micrograms/ml), a lipoxygenase inhibitor, decreased release. The chemotactic activity was heat stable for 30 min at 56 degrees C and was extractable into ether at pH 3.0. Analysis of 15- and 30-min supernatants showed coelution of biologic activity and of leukotriene B4 (LTB4), as measured by radioimmunoassay, at marker positions of LTB4 and of 20-OH-LTB4. Elimination of Langerhans cells did not alter the secretion of chemotactic lipids, suggesting that keratinocytes are the main source of potent, biologically active, lipoxygenase-dependent arachidonate metabolites.

Activation of human eosinophils by monokines and lymphokines: source and biochemical characteristics of the eosinophil cytotoxicity-enhancing activity produced by blood mononuclear cells

We and others have previously reported that human blood mononuclear cells release in culture certain substances that enhance the capacity of purified human blood eosinophils to kill the antibody-coated larvae of Schistosoma mansoni. The present study shows that this eosinophil cytotoxicity-enhancing activity (ECEA) is released by monocytes and T lymphocytes. Monocytes produce ECEA in resting and in LPS-stimulated cultures; T lymphocytes release such activity when stimulated by mitogens such as concanavalin A. Furthermore, the human monocytic line U-937 also releases ECEA-like activity when stimulated by LPS. The enhancing activity produced by monocytes has been partially characterized: it is sensitive to proteolysis by trypsin, relatively heat stable, and associated with molecules that have an apparent molecular weight of 14,000 to 65,000 daltons and isoelectric points of 3.8-3.9, 4.2, 4.5, 4.8-4.9. This shows that while ECEA produced by monocytes is heterogeneous in size and charge, it is probably different from interleukin 1.

Leukotriene B4 induces in vitro fibroblast chemotaxis

In vitro fibroblast chemotaxis was studied in the presence of synthetic leukotriene B4 (LTB4) and of supernatants from ionophore-stimulated lymphocytes, monocytes, and basophils (LMB-S). LTB4 and LMB-S induced a dose-related, directed migration of human and rat embryonic fibroblasts. By checkerboard analysis, this response was chemotactic and not chemokinetic. Optimal migration toward LTB4 occurred at 10(-8) M concentrations, while higher concentrations were inhibitory. The LMB-S contained two types of fibroblast chemotactic factors, one that corresponded to LTB4 and one additional, heat labile, non-dialyzable substance of greater than 10 kilodaltons. LTB4 and LMB-S were inactive against transformed human connective tissue cells (HT 1080, McCoy) while these cells moved well in response to conditioned medium derived from confluent fibroblast monolayer cultures. These results suggest that LTB4 is a specific chemoattractant for fibroblasts and that it acts in concert with other chemotactic factors derived from inflammatory leukocytes to regulate the influx of fibroblasts to tissue sites.

The effect of eosinophil chemotactic factors on in vitro eosinopoiesis in the guinea pig

The influx of eosinophils to tissue sites is regulated by several well-characterized eosinophil chemotactic factors. In the present investigation the effect of such factors on eosinopoiesis was studied in guinea pig liquid bone marrow cultures. Addition of neutrophil-derived eosinophil chemotactic leukotrienes, synthetic leukotriene B4, zymosan-activated serum, purified hog C3a, C5a, C5a-des-arg, and synthetic N-formyl-methionyl-phenylalanine did not increase eosinophil numbers in marrow cultures, while supernatants of spleen or lymph node cells stimulated by concanavalin A were highly effective. 3H-thymidine labelling of cultured eosinophils was not increased by any of the added mediators. A quantitative correlation between eosinopoietic and eosinotactic activity could not be established. These in vitro data suggest therefore that eosinopoiesis and migration of guinea pig eosinophils to tissue sites are regulated by separate chemical mediators.

Effect of platelet activating factor on leukocytes. II. Enhancement of eosinophil chemotactic factor and beta-glucuronidase release

Synthetic 1-O-alkyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (PAF) and 1-O-alkyl-sn-glyceryl-3-phosphorylcholine (lyso-PAF) have previously been shown to induce chemotaxis and chemokinesis of human neutrophils. We present here data showing that these agents are inactive by themselves, but that they enhance neutrophil secretion once it has been initiated by a calcium ionophore or by zymosan. Two substances, the lipid eosinophil chemotactic factor (ECF) and the lysosomal enzyme beta-glucuronidase, are used as markers for neutrophil release. PAF augments secretion of both substances in a dose-dependent fashion, with lyso-PAF being less potent. The kinetics of enhancement are very rapid (less than 2 min) and are not reversible by washing of the cells. A pyrazoline derivative that inhibits arachidonate cyclo-oxygenation and lipoxygenation, reduces the enhancing effect of PAF and lyso-PAF. PAF, and less so lyso-PAF, are thus potentially important modulators of neutrophil secretion during inflammatory processes.

Eosinophilia VI, spontaneous synthesis of chemokinetics, chemotactic, complement receptor-inducing activities for eosinophils by bronchial t lymphocytes of asthmatic-bronchitic patients

T lymphocytes were separated from the bronchial mucus of five patients with extrinsic asthma and chronic and mild bronchitis and who had numerous eosinophils in the bronchial mucus but no significant blood eosinophilia. The bronchial lymphocytes spontaneously, that is without treatment with antigens or mitogens, released into serum-free synthetic medium one or more substances in the molecular weight range of 30 000 to 60 000 daltons. These substances when tested on eosinophils of normal persons stimulated random movement (chemokinesis), attracted them (chemotaxis), enhanced their chemotactic response to activated complement, and increased the expression of C4 and C3b receptors. Chemokinetic and chemotactic activity for neutrophils was weak. No eosinophil-stimulating activity was found in cultures of bronchial lymphocytes treated with puromycin to inhibit synthesis. The blood lymphocytes did not spontaneously synthesize the substance(s). It is not known if the several eosinophil-stimulating activities are due to one or more substance(s), but the nature of the eosinophil responses, molecular weight and other features, indicate similarities with the 'eosinophil stimulation promoter-chemotactic' factor reported to be released from mouse or human lymphocytes treated with antigen. Eosinophil stimulation resulting in increased expression of specific receptors, and potential for non-specific adherence, by trapping or arresting randomly migrating cells, is believed to mediate accumulation of cells in an affected organ. Prolonged synthesis of such products as from activated lymphocytes in the lung, could account for much of the local eosinophilia.

Effect of 1-O-octadecyl-2-O-acetyl-sn-glycero-3-phosphocholine (PAF-acether) on leukocytes I. Analysis of the in vitro migration of human neutrophils

The effect of synthetic 1-O-octadecyl-2-O-acetyl-sn-glycero-30-phosphocholine (PAF-acether) and of 1-O-octadecyl-sn-glycero-3-phosphocholine (lyso-PAF-acether) on human neutrophil migration was studied in modified Boyden chambers, with the following results: (1) By checkerboard analysis and deactivation experiments, the factors are chemokinetic at low (10(-8) M) and chemotactic at higher concentrations (10(-6) M), with lyso-PAF-acether being less potent at all concentrations. (2) Cross-deactivation occurs between the two PAF compounds, but not with two other chemotactic factors, suggesting a specific, common receptor for the PAFs on the neutrophil membrane. (3) Other chemotactic substances may act as potentiating or additive factors to the PAF compounds. (4) Inhibition of arachidonic acid turnover during chemotaxis by compound BW 755 C enhances leukocyte chemotaxis towards the PAF compounds and towards other chemotactic factors. The data suggest that PAF and its lyso-derivate may contribute in a unique and potent fashion to leukocyte accumulation at inflammatory sites.