I am trying to determine whether the strength of the respiratory burst directly correlates with "how activated" the phagocyte becomes when it comes into contact with a surface/biomaterial. Can someone suggest prior research in this area that I have missed thus far?
Our own experience comes from recording (patch-clamp) from human neutrophils and eosinophils suspended on glass cover slips. Once the cells settle and attach, they frequently become "activated." We detect this is two ways: (a) the properties of proton channels change, with gating becoming "enhanced" so that more channels open for a given stimulus, and (b) we measure electron current that directly shows the activity of NADPH oxidase. I am not sure quite what your question is getting at; the activation by adherence seems weaker than by PMA, which gives a maximal response. The adherence activation is reversible with time, and the same cell can be re-activated by subsequent application of PMA. This is described in p. 769 of the attached.
Thanks Thomas! Great answer, and very helpful. What is the "attached"? I don't see an attachment.
Sorry - I tried to attach a pdf via ResearchGate, but it seems not to have worked. You can email me at [email protected] and I will send the pdf.
The reference is
DeCoursey, T.E., V.V. Cherny, A.G. DeCoursey, W. Xu and Thomas, L.L. 2001. Interactions between NADPH oxidase-related proton and electron currents in human eosinophils. J. Physiol. 535:767-781.
Dear Mr Palmer,
I would not consider the respiratory burst as an indicator for innate immune cell activation. Did you think about measuring cytokines ? Cytokines are important because they also act on other cells or even on tissues or organs.
Best,
Matthias.
Matthias, thank you for the suggestion. The design of the study focuses on the respiratory burst as we are using biomaterials that will specifically enhance or repress it. I am trying (mentally/literature search) to understand what the meaning and consequence of an increased, a delayed or a depressed burst is. I can infer direct or indirect action on NADPH oxidase, or on the assembly, or regulation thereof; but I would really like to understand what is happening. Does a delay mean that the biomaterial or agent is preventing ROS, as a quenching effect? If there is no change in the total ROS, just a delay in peak time, what does this mean? Is it possible to use the cytokine or downstream effect responses to answer these questions? I think after addressing these questions, the next step would be cytokines and intercellular effects.
If you have any recommendations on literature linking the ROS to activation levels, or a paper that describes the different levels of activation (for instance does larger ROS indicate a more active/fighting neutrophil) I would be very interested!
Thanks!
Thomas, I found your 2005 paper on regulation and termination of the NADPH oxidase very helpful and will certainly be citing it. Thank you again for the suggestions. I am looking more at the actual ROS via luminol, rather than the initiating currents prior to/during NADPH oxidase assembly, so I am stilling look for information on how antioxidants effect the respiratory burst and the subsequent effect on the individual cell's inflammatory state/kinetics, and the intercellular signalling effects.
Thanks for the kind words. I do not think I have any additional insight into your questions. We have focused on events leading to and during the burst, and the direct consequences (electrical and pH).
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