PubMed · 7424848
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A J Khan, W Rosenfeld, R Jhaveri, D Salazar, H E Evans. 1980. Human milk.. https://doi.org/10.1001/archpedi.1980.02130220078037
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Human eosinophils produce upon treatment with 5-oxo-eicosatetraenoic acid or (5S,15S)-dihydroxyeicosatetraenoic acid a potent eosinophil-chemotactic eicosanoid, 5-oxo-15-hydroxy-(6E,8Z,11Z,13E)-eicosatetraenoi c acid (5-oxo-15-HETE). 5-Oxo-15-HETE induces human eosinophil (Eo) chemotaxis at nanomolar concentrations with an efficacy in vitro comparable to that seen for platelet activating factor. Comparison of Eo chemotactic activities of several structurally related eicosanoids with different substituents and/or double bound geometry led to the conclusion that maximal potency and efficacy of eosinophil-chemotactic and chemokinetic activity is present in 5-oxo-(6E,8Z,11Z,14Z)-eicosatetraenoic acid (5-oxo-ETE). The presence of a hydroxyl group at position C-15 is not necessary for potent chemotactic activity, whereas a geometric isomer having trans instead of cis double bond at C-atom 8, as well as esterified 5-oxo-ETE usually show a 5-10-fold lower potency. 5-Oxo-eicosanoids elicit a dose-dependent transient rise of intracellular Ca2+ levels in human Eos, however, in contrast to some other Eo chemotaxins do not induce degranulation. Cross-desensitization of Ca2+ mobilization and Eo chemotaxis revealed that the geometric isomers of 5-oxo-eicosanoids, 5(S)-HETE, and (5S,15S)-di-HETE cross-deactivate Eo responses to each other, whereas other, unrelated stimuli did not interfere with these lipids indicating that 5-oxo-eicosanoids activate Eos via a separate receptor.
The ability of neutrophils to migrate through three-dimensional (3-D) tissues in response to chemical stimuli is critical to their host defense function. However, studies characterizing stimulated migration in vitro have been largely limited to two-dimensional (2-D) surfaces. In this study, we have employed direct observation methods to quantify human neutrophil migration in 3-D fibrin gel using time-lapse video microscopy and automated cell tracking methods. A novel 3-D conjoined gel assay was developed to establish experimentally quantifiable and theoretically predictable diffusion gradients of chemotactic factors. This assay was used to measure objective migration parameters, namely the random motility and chemotaxis coefficients, in response to the cytokine, interleukin-8 (IL-8). The random motility coefficient, mu, showed a biphasic dependence on IL-8 concentration with a maximum of 1.1 x 10(-8) cm2/s at 5 x 10(-8) M IL-8; no significant motility was observed in the absence of IL-8. We further established the dependence of cell orientation bias, phi, on the concentration and gradient steepness (i.e., specific gradient, SG) of IL-8. Results indicate that phi increases with increasing SG, provided the concentration is maintained sufficiently low, which we conjecture to result from minimizing IL-8 receptor down-regulation. The chemotaxis coefficient, chi, was maximum at an intermediate SG for both IL-8 concentrations studied. We also examined the applicability of this assay to estimate mu and chi from indirect measurements of chemotaxis, namely the simpler measurement of cell redistribution after a prescribed incubation time, as opposed to direct cell tracking measurements. By virtue of measuring chi, this is the first quantitatively objective study of mammalian cell chemotaxis in a physiologically relevant 3-D gel and, in particular, of neutrophil chemotaxis on any substratum in response to the physiologically relevant chemotactic factor, IL-8.
OBJECTIVE: To characterize the molecular nature of the chemotactic signal for sperm contained in human follicular fluid (FF). DESIGN: Follicular fluid was fractionated and several procedures were followed to the physicochemical initial characterization of sperm chemotactic compound(s). MAIN OUTCOME MEASURE: Relative chemotactic activity of each fraction was measured in a double chamber device. RESULTS: Sperm chemotaxis was found to be associated with a lipid-like molecule extracted from FF. Several steroids were assayed individually and only P showed sperm chemotactic properties in dose-response curves. CONCLUSIONS: In this paper we present experimental evidence to support the hypothesis that P, the main steroid component of FF, is a mediator of sperm chemoattraction in human beings.