neutrophil phagocytosis assay

Tests fonctionnels des neutrophiles pour le criblage de différentes voies de signalisation

Neutrophils are the most abundant innate immune cells in human blood and are known to play a major part in infection and inflammation, being the first responders to arrive at the site of tissue damage1. In recent years, there has been a growing recognition of the crucial role that neutrophils play in a variety of diseases and in supporting homeostasis2. Neutrophils not only have tightly regulated signaling themselves, but also participate in the regulation of other components of the immune system3,4,5. Therefore, investigating neutrophils and their many unusual cellular functions, such as chemotaxis, reverse migration6, phagocytosis7, respiratory burst8, and the release of neutrophil extracellular traps (NETs)7, is imperative in numerous research contexts where it is necessary to assess the potential neutrophil functional, morphological, or molecular changes triggered by specific conditions under analysis.
Freshly isolated neutrophils are terminally differentiated, short-lived, highly dynamic, and easily activated9. However, an efficient storage method that does not affect the neutrophil responses has not yet been achieved, making it challenging to perform multiple assays that must be uninterrupted. Furthermore, previously described functional analyses10,11, based on assays that require cytometry and/or fluorescent staining, may not be a viable choice when a broad and initial evaluation of the neutrophil is needed.
To address these issues, this protocol describes a set of tests that can be carried out following a single isolation process, including the evaluation of cell viability, reactive oxygen species (ROS) production, real-time migration, and phagocytosis of Saccharomyces cerevisiae, whose results can be used to reason in-depth follow-up studies. This procedure, named NeutroFun Screen, was designed to encompass the leading effector activities, except degranulation, and can be completed in an average time of 4 h, including 1 h of activation. Additionally, the remaining cells can be used for more detailed approaches like omics studies. The advantage of this method lies in its balance between speed, comprehensiveness, cost, and accuracy.
Furthermore, there is a way to easily observe a preliminary suggestion of NETs, without specific markers, but enough to indicate if further efforts in that direction would be worthwhile. The diversity of functions tested aims to combine common points among tests, reducing the analysis time and expenses. The main goal of this method is to provide a balanced, functional analysis regarding speed, comprehensiveness, cost, and accuracy that allows for an overview of the neutrophil&#39;s response, making it a useful initial step in investigating the effects of novel stimuli on normal density neutrophils.

Pleins feux sur l’auteur : Équilibrer la vitesse, le coût et la précision dans l’évaluation de la fonction des neutrophiles avec le protocole NeutroFun Screen 

Un ensemble de techniques de dépistage pour un aperçu rapide de la fonction des neutrophiles

Watch this Scientific Journal Video about Neutrophil Phagocytosis Assay at JoVE.com

Dosage de la phagocytose neutrophile

Ajoutez environ 0,75 milligramme de levure sèche à 200 microlitres de solution saline équilibrée Hanks', ou HBSS, contenant des ions calcium et magnésium. Ensuite, incubez le mélange dans un ThermoMixer à 100 degrés Celsius et 500 tr/min pendant au moins 15 minutes. Après incubation, transvaser cinq microlitres de suspension de levure dans 45 microlitres de colorant bleu de trypan à 0,2 %.Comptez les cellules de levure à l’aide d’une chambre Neubauer. Ajustez la concentration de la suspension initiale à 33 000 cellules de levure par microlitre en utilisant HBSS avec du calcium et du magnésium. Ensuite, mélangez et transférez délicatement cinq microlitres de polynutrophiles activés préalablement préparés à cinq microlitres de suspension de cellules de levure dans un nouveau tube de microcentrifugation stérile.Transférez immédiatement six microlitres de neutrophiles polymorphonucléaires et de suspension de levure dans trois puits d’une lame de verre propre, de deux microlitres chacun, et incubez la lame dans une chambre humidifiée pendant 40 minutes. Après la coloration avec un panoptique rapide, observez les cellules au microscope. Bien que le FMLP à 100 nanomolaires et le peptide antimicrobien à 16 micromolaires aient induit une augmentation de l’engloutissement de levures, la différence n’était pas statistiquement significative jusqu’à la double stimulation, qui a considérablement amélioré la phagocytose par rapport au groupe témoin.

Research

JoVE Journal

Immunology and Infection

Neutrophil Phagocytosis Assay

225 vues. Ajoutez environ 0,75 milligramme de levure sèche à 200 microlitres de solution saline équilibrée Hanks', ou HBSS, contenant des ions calcium et magnésium. Ensuite, incubez le mélange dans un ThermoMixer à 100 degrés Celsius et 500 tr/min pendant au moins 15 minutes. Après incubation, transvaser cinq microlitres de suspension de levure dans 45 microlitres de colorant bleu de trypan à 0,2 %.Comptez les cellules de levure à l’aide d’une chambre Neubauer. Ajustez la concentr...

Vidéo: Dosage de la phagocytose neutrophile

A Set of Screening Techniques for a Quick Overview of the Neutrophil Function

Neutrophils are known as one of the first lines of defense in the innate immune response and can perform many particular cellular functions, such as chemotaxis, reverse migration, phagocytosis, degranulation of cytotoxic enzymes and metabolites, and release of DNA as neutrophil extracellular traps (NETs). Neutrophils not only have tightly regulated signaling themselves, but also participate in the regulation of other components of the immune system. As fresh neutrophils are terminally differentiated, short-lived, and highly variable among individuals, it is important to make the most of the collected samples. Researchers often need to perform screening assays to assess an overview of the many neutrophil functions that may be affected by specific conditions under evaluation. A set of tests following a single isolation process of normal density neutrophils was developed to address this need, seeking a balance between speed, comprehensiveness, cost, and accuracy. The results can be used to reason and guide in-depth follow-up studies. This procedure can be carried out in an average time of 4 h and includes the evaluation of cell viability, reactive oxygen species (ROS) production, real-time migration, and phagocytosis of yeast on glass slides, leaving enough cells for more detailed approaches like omics studies. Moreover, the procedure includes a way to easily observe a preliminary suggestion of NETs after fast panoptic staining observed by light microscopy, with a lack of specific markers, albeit enough to indicate if further efforts in that way would be worthwhile. The diversity of functions tested combines common points among tests, reducing the analysis time and expenses. The procedure was named NeutroFun Screen, and although having&#160;limitations, it balances the aforementioned factors. Furthermore, the aim of this work is not a definite test set, but rather a guideline that can easily be adjusted to each lab&#39;s resources and demands.

This protocol features a set of neutrophil functional assays to be used as a screening method to cover functions from different signaling pathways. The protocol includes an initial and simple evaluation of cell viability, purity, reactive oxygen species production, real-time migration, phagocytosis, and a preliminary suggestion of neutrophil extracellular traps.

Neutrophils are known as one of the first lines of defense in the innate immune response and can perform many particular cellular functions, such as ...

Recherche

Immunologie et infection

Neutrophil Isolation and Activation

Isolement et activation des neutrophiles

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Dosage du chlorure bleu de nitrotétrazolium (NBT) pour l’évaluation de la production de ROS

Real-Time Polymorphonuclear Neutrophils (PMN) Chemotaxis Assay

Dosage de chimiotaxie des neutrophiles polymorphonucléaires (PMN) en temps réel

Neutrophil Extracellular Trap (NET) Suggestive Assay

Piège extracellulaire neutrophile (TNE) Dosage suggestif