Talk:Phagocyte/Archive 3

Harmful

Colin suggested "harmful" in the first sentence. I have inserted it twice but it is missing again. Is the final verdict that the typical reader consider it obvious that it is a good thing that foreign particles, bacteria and dying cells are removed? --Ettrig (talk) 08:15, 4 March 2009 (UTC)

• You are right, "harmful" should go in and I have restored it. We also need to say "protect the body" or something similar. Secondly, I owe you an apology for reverting one of you edits. My only excuse is that you described it as "taking a stab at improving", which gave me the impression that you were not 100% happy with it. Graham. Graham Colm ^Talk 18:49, 4 March 2009 (UTC)

Professional/non-professional last

I think it is a good idea to proceed from general aspects to specifics. This would entail describing common characteristics before differences. This helps understandability. In this article the sections about professional and non-professional should be moved far down. This would for example have the effect that phagocytosis is described before this concept is used to define the difference between professional and non-professional. --Ettrig (talk) 20:24, 10 March 2009 (UTC)

I agree with moving the phagocytosis section up, but I still think the professionals should come before the amateurs. This is how it is done in many books. Graham. Graham Colm ^Talk 20:49, 10 March 2009 (UTC)

I agree with professionals should come before the amateurs (in this context). And this is not in conflict with my suggestion above. ... Ah, but I now finally see that the headline suggests something other than the text, so changing professional last => Professional/non-professional last. --Ettrig (talk) 07:47, 11 March 2009 (UTC)

Eulemur, do you accept this suggestion? Graham. Graham Colm ^Talk 18:32, 11 March 2009 (UTC)

Well, it took me quite awhile to join in on this conversation, but yes I do agree with this suggestion. --Eulemur2008 (talk) 22:13, 11 March 2009 (UTC)

So, who wants to increase their edit count?  :-) Graham Colm ^Talk 22:18, 11 March 2009 (UTC)

If there was such a syndrome as "wikidormancy syndrome" I probably had this for the past several weeks. However, I am now making time for editing instead of procrastinating. --Eulemur2008 (talk) 00:13, 12 March 2009 (UTC)

Major edits

In light of Colin's and Brian's comments (above and at peer-review) it is clear that the article is very opaque (to the point of being unreadable) in places. I am going to spend a lot time this week addressing the issues raised. This will involve some radical editing in places, but to get this to FA level this must be done. Graham. Graham Colm ^Talk 16:30, 16 March 2009 (UTC)

Eulemur has done an outstanding job adding content; however, many of my sophomore writers have not had the benefits of Junior and Senior English Classes. Any edits for improvement would be deeply appreciated, I'm certain.--JimmyButler (talk) 21:58, 16 March 2009 (UTC)

Jimmy, Eulemur has indeed done an outstanding, commendable and admirable job adding content to the article. There are few problems with the prose as such but the article, in places, goes into just a little more detail than is needed for an encyclopedia and I have boiled down some of his well-researched edits into more digestible, (no pun intended), pieces. Eulemur has shown me and you, his teacher, the depths of his newly gained knowledge on the subject, but now it is time to go for FA. To achieve this, we have to take Colin's and Brian's criticisms on board. Colin is the perfect lay-reader in my opinion—intelligent, articulate, critical and curious—if he finds this contribution opaque and an unrewarding read, then we are wasting our time. And Brian, is one of Wikipedia's finest writers. Eulemur, my friend and collaborator, we have to bite the bullet now and make some radical changes to the article. We have to remove superfluous detail, (and yes I know this is hard to define) and get this to the stage where it is understandable and engaging to the lay reader. It's not that far off. We have to ask ourselves why we are writing this. If it is just to please Mr. Butler, then this is not a good reason. If it is to impress friends and family; this is not a good reason. If it is solely to achieve FA; this is not a good reason. A good reason is to clearly explain to the world the importance of our phagocytes and the role they play in keeping us alive. If we can do this, the FA star will be surely be deserved, but more importantly readers and friends like Colin and Brian will learn something—and this is the best reward. Graham. Graham Colm ^Talk 22:35, 16 March 2009 (UTC)

History Section

The opening line alludes to a debate between two different perspectives of immunity. Would it be a good idea to define these two different views - quickly. The topic sentence (the debate) does not seem to be address in the content to follow. I do not see any reference to humoral immunity at all in the lines to follow. I keep coming back to the history section as the section that is the least coherent.

During the late nineteenth and early twentieth centuries, a debate developed between the supporters of the cellular and humoral theories of immunity; Ilya Ilyich Mechnikov] was a supporter of the cellular theory.--JimmyButler (talk) 13:37, 20 March 2009 (UTC)

Perhaps simply state Ilya Ilyich Mechnikov contributed to the cellular theory of immunity by studying... and make no reference at all to the the debate or alternative view?--JimmyButler (talk) 13:41, 20 March 2009 (UTC)

I agree, the debate was minor and on emphasis rather than exclusion. I think we a can delete the statement. Graham. Graham Colm ^Talk 14:08, 20 March 2009 (UTC)

Ready for FAC?

I think the time has come to consider nominating the article for FA. I have, I hope, addressed most of Colin's and Brian's points, although a lot of scientific terminology remains. I cannot, at the moment, see how to avoid this completely. What do others think? Graham. Graham Colm ^Talk 19:34, 20 March 2009 (UTC)

I'm very impressed with the changes made this week. I particularly enjoyed the Phagocytosis section . I've read up to "Role in apoptosis" so far. I can't really comment on its readiness until I've finished but it is looking good so far. Here are some comments on this version:

If the article is in US English, I wonder if ameba (and amebas) should be used? Any US editors got an opinion?

The Phagocytosis section describes how receptors are used. But these appear to be only available on the professional phagocytes, and presumably only work on foreign material. How about host material, and non-professional phagocytosis?

The myeloperoxidase article implies this lends the green colour to snot. If this is true, it is a fact that should not be ignored!

The Extracellular killing section is a bit hard. It isn't clear where the interferon-gamma comes from (and the "In macrophages, interferon-gamma..." makes me think it is self-produced by the macrophages, which I think is wrong). Do I need to know it was "once called macrophage activating factor"? Can we shorten some of the explanation by saying "produce and secrete" just like you do with TNF? And "because of its toxicity" could be shortened to just say "produce and secrete toxic nitric oxide, which kills any nearby invading microbes"? The word "cytokine" is used without explanation. The cytokine article says these are "signalling molecules" (and I note that interferon-gamma is also a cytokine). But if TNF "kills" then it appears the "signalling" aspect isn't relevant here. Confused.

I need to check, what, if anything I have doene about this. (Memory is fading). Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

I'm reading the "Role in apoptosis" section and followed the links, etc. I don't think this is given enough importance. I know about programmed cell death (which we should link to) and how it forms the body and maintains a balance of new and old cells. But I had never considered what happens to those dead cells. It appears phagocytes are vital for clearing up this stuff. What is apoptosis, and why is it important? tells me "In adulthood, about 10 billion cells die every day simply to keep balance with the numbers of new cells arising from the body's stem cell populations". The Apoptosis article lead has some other amazing facts and figures but they aren't sourced so I'm not confident with them. If they are true then there is a huge quantity (and weight) of material that these guys much through each year. Apoptosis: A Review of Programmed Cell Death tells me more about the phagocytosis. This apoptosis mechanism was only discovered in 1972! I continue to be amazed at how much biology is recent. So there's a role in the formation and maintenance of the body. This needs to be mentioned in the lead and given more space in this section. Also, highlight that this is a normal, healthy process ("programmed process" doesn't do that for me, even though "programmed" is part of the well-known term).

Colin°^Talk 23:54, 21 March 2009 (UTC)

Hi Colin, this is just to acknowledge that I have read this and that I like your edits. It's bedtime, as you know, so if my American colleague does not beat me to it, I will address your comments on Sunday. Do people really not know why snot is green? Green snot, by the way, is full of phagocytes; if we did not have these friendly little chaps crawling around inside us, we would die in about three days. I hope at least the article will explain one of the big mysteries many people first encounter in childhood; what is pus, where does it come from and what does it do? (The other one of course is "what does it taste like" but I am not going there)! Dear Colin, thanks again for the help that you have given here. As always, your time and thoughts are (sorry about the cliché) very much appreciated. Graham. Graham Colm ^Talk 00:19, 22 March 2009 (UTC)

Thank you, Colin, for another helpful review of the article. "Ameoba" is fine, this is how I spell it. I believe I cleaned up the extracellular killing section (just a little bit); however I am still debating whether the signaling aspect of TNF is relevant. --Eulemur2008 (talk) 15:25, 22 March 2009 (UTC)

Why does the article say "The principal professional phagocytes are now known to be the monocytes, macrophages, neutrophils, tissue dendritic cells and possibly mast cells."? In particular "now known" and "possibly". We don't normally profess to past ignorance so why not just state the current knowledge as fact. Why are mast cells only a "possibly"? Is the definition of "professional" under debate or are we just unsure if they are all a bunch of amateurs? If there is doubt here, and it is notable, then could we say more? Colin°^Talk 23:28, 25 March 2009 (UTC)

I have removed the caveat, and the redundancy. Graham Colm ^Talk 11:28, 26 March 2009 (UTC)

"some become large enough to engulf invading protozoa" The bacteria article gives a size range from 0.5 to 5 um (but some up to 0.5mm). The protozoa article gives a size range from 10 to 50 um (but some up to 1mm). Could we say ", which are typically ten times larger than bacteria"? Colin°^Talk 23:42, 25 March 2009 (UTC)

Most protozoa that enter the human body are rather small, such as Toxoplasma Plasmodium or most importantly here Leishmania, which invade and then replicate inside macrophages as their preferred host cell. Tim Vickers (talk) 23:59, 25 March 2009 (UTC)

Yes, there are a couple of good images on Commons of Leishmania inside macrophages, but I opted for the ricketsia image thinking it would be more easily understood. It would still be nice to include one, but I can't find the space. Graham Colm ^Talk 11:28, 26 March 2009 (UTC)

I'm hurt, Leishmania are both fascinating and photogenic. ;) Tim Vickers (talk) 16:18, 26 March 2009 (UTC)

Leishmania amastigotes inside macrophages

I agree with you on both counts. I like this one, but it is not sourced very-well. Graham Colm ^Talk 17:36, 26 March 2009 (UTC)

Yes, the metadata for that file state that the image was taken with a sony handheld digital camera. I don't see how that would be possible. Tim Vickers (talk) 17:50, 26 March 2009 (UTC)

Well, it was rather cumbersome. I had to take several pictures, then chose one with acceptable quality and cropped it. Anyone can try it themselves by placing the camera lens directly againt the microscope ocular. Cumbersome, but possible. --Abanima (talk) 13:55, 27 March 2009 (UTC)

This one should be acceptable, it's from CDC:

Leishmania tropica amastigotes (arrows) in macrophage from skin

Graham Colm ^Talk 17:58, 26 March 2009 (UTC)

Thanks for adding the protozoa stuff, Tim. However, the "Pathogen evasion and resistance" lead now talks about "disrupting cell signalling to prevent the phagocyte responding to invasion" as a common mechanism -- but this isn't mentioned in the four sub-sections that deal with the strategies in detail. Perhaps "Signalling disruption" should be another sub-section? Colin°^Talk 21:13, 26 March 2009 (UTC)

I don't think a full section on this is needed. I think we could change this to disrupting cytokines. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

Which might make room for the CDC picture. Graham Colm ^Talk 21:43, 26 March 2009 (UTC)

• Migration: I'm a bit puzzled by the "Another group of chemical attractants are chemokines which recruit neutrophils and monocytes from the blood." sentence. It appears that chemokines are a type of cytokine and we know that neutrophils and monocytes are two kinds of phagocyte. So what is this sentence telling us that isn't mentioned earlier? If we want to mention the term "chemokine" perhaps there is another way? The following paragraph talks of a chemokine scent, but this paragraph mentions all sorts of attractant signals, not all of which are "chemokines" (are they)? Are all of these actually attractants, or are some of them helpers like the vasodilators and selectin proteins in the next paragraph? Colin°^Talk 22:22, 26 March 2009 (UTC)

It is very confusing, but as I understand it, chemokines, cytokines and leukokines are all classed as the same thing these days. Tim Vickers (talk)

Indeed they are, but which word should we use? I prefer "cytokines" because "they" make cells move. Graham Colm ^Talk 22:59, 26 March 2009 (UTC)

I have changed to cytokines througout. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

• Macrophages: "Unlike dendritic cells, mature macrophages do not travel far." This sentence confuses me. Until this point in the article, I didn't know dendritic cells travel far -- the dendritic cell section is later. Could this fact be moved to the later section? Also, both cells appear to lie in wait in the same kind of tissue -- that exposed to the outside world. It appears that the dendritic cells then move to the lymphoid tissues when activated but I guess the macrophages stay put. Can this be clarified a bit. Colin°^Talk 22:49, 26 March 2009 (UTC)

I have clarified (and simplified a bit), this section. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

Yes, Colin, your are right, oh my, it's so complicated - bloody networks -basically macrophages "hang out" in the solid tissues, but dendritic cells commute. I will try to make this clearer in the morning. Graham. Graham Colm ^Talk 22:59, 26 March 2009 (UTC)

• Macrophages: "The signals then allow the macrophage to effectively kill the ingested microbes." So the macrophages have eaten the microbes but are waiting on permission to kill them? Can a microbe be ingested but not killed? What does "effectively kill" mean that is different from "kill". Do you mean they become more effective killers? How? Also, the macrophage article has the wonderful (unsourced) fact that "Macrophages can digest more than 100 bacteria before they finally die due to their own digestive compounds." Can we have this here too please? It paints a lovely picture. Colin°^Talk 23:09, 26 March 2009 (UTC)

Yes, some bacteria can be ingested but not killed and this is covered later. I have deleted "effectively". I don't believe the unsourced "100 bacteria before they die" sentence, it will be more or less, depending on the size of the bacterial cells and any evasion mechanisms they have. The gonnococcal image shows just how many they can eat at any one sitting. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

• Dendritic cells: 1. They are found in tissue exposed to external environment. 2. They can be found in an immature state in the blood. 3. They mature and migrate to the lymphoid tissues. The second two facts seem to imply they go from immature cells in the blood to mature cells in the lymph. What about the skin and linings of the nose, lungs, stomach and intestines. Can they be immature/mature there too? Do only the immature blood cells mature and go to the lymph tissues or are there immature cells in the external-facing tissue too? Can they mature without migrating to the lymph? Colin°^Talk 23:43, 26 March 2009 (UTC)

I have clarified this, (I hope). Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

• Non-professional Phagocytes: Why does the table not also have a "Location" column like the professional one. Could it then be centred to match the other one too? Colin°^Talk 17:21, 27 March 2009 (UTC)

Done that. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

• Opsonin: The first time the article mentions the word "opsonin" is wrt the lack of receptors for these by non-professionals. Reading the opsonin article and the Antibody opsonization article makes me think this is a key concept that isn't being mentioned by name in the relevant section earlier in the article. The former article notes the negative charge in the membranes of both cells, making it hard for them to come together. This idea of like-charges repelling is easy to grasp and appreciate that it is a problem to solve before the cells can make contact. BTW: the "The main difference between" sentence is hard to read. I first thought the "—which are antibodies and complement attached to invaders by the immune system—" definition applied to "receptors for opsonins", not "opsonins". This is made harder by the difficulty I have reading the word "complement" being used the way biologists use it. Colin°^Talk 17:21, 27 March 2009 (UTC)

I have added one of my little diagrams, added a section on opsonins to the History and clarified their mention in the phagocytosis section. Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

Thanks Colin, this is just to acknowledge that I have read this. I have no time this evening to work on the article, but will have tomorrow. I am trying to find where in all these books and papers, I read that "opsonin" comes from the German for "to prepare for eating" - then again I might have dreamt this. I have been dreaming about phagocytes a lot of late, but it makes a change from viruses. Thanks again and all the best, Graham. Graham Colm ^Talk 18:00, 27 March 2009 (UTC)

According to Encarta and The American Heritage Dictionary of the English Language it comes from the Latin "to buy provisions" which in turn comes from the Greek "condiment, delicacy". I've now got an image of phagocytes pouring some tomato ketchup on the bacteria before they eat them :-) Colin°^Talk 18:58, 27 March 2009 (UTC)

I have mentioned the "ketchup". :-) Graham Colm ^Talk 15:09, 28 March 2009 (UTC)

Colin, thanks again. I hope today's efforts have improved the article. Graham.

Arbitrary break

• Alberts, Bruce (2002). Molecular Biology of the Cell; Fourth Edition. New York and London: Garland Science. ISBN 0-8153-3218-1. Retrieved 2009-03-20. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

The above reference is to an entire book, and needs a page number. However the URL goes to the online-contents and from that it appears to be possible to search and read the book contents. For example this page. Could you locate the page(s) that support the two citations here and provide the correct URL. It may be the reference needs split in two if each citation is actually on a different page/URL. Colin°^Talk 21:12, 28 March 2009 (UTC)

I used Delves instead for this one. It says the same thing. Graham Colm ^Talk 10:29, 29 March 2009 (UTC)

• Gilman A, Goodman LS, Hardman JG, Limbird LE (2001). Goodman & Gilman's the pharmacological basis of therapeutics. New York: McGraw-Hill. ISBN 0-07-135469-7.{{cite book}}: CS1 maint: multiple names: authors list (link)

The above reference is to an entire book and needs a page number and edition (I think the ISBN is for the 10th). We can't expect the reader to scan all 1825 pages to verify that a cytokine is "a class of signaling molecules"! Colin°^Talk 23:37, 28 March 2009 (UTC)

Again, Delves is much better on this. Graham Colm ^Talk 10:29, 29 March 2009 (UTC)

In the introduction: Phagocytes of humans and other higher animals Are the other higher animals - mammals? - primates? No evolutionary ladders with humans at the top, Eulemur! :-)--JimmyButler (talk) 00:20, 29 March 2009 (UTC)

Jawed vertebrates to be precise. And, Eulemur, sadly, gives the impression that he no longer wants to be involved here. Graham Colm ^Talk 00:45, 29 March 2009 (UTC)

(inserted) Ummmmmm this makes things complicated regarding grading. The FA reward is major. I had not anticipated a student not following through - yet the article being carried to FA level by others. --JimmyButler (talk) 00:58, 29 March 2009 (UTC)

When the phagocytes come into contact with the bacteria, they bind to the receptors on the phagocyte's surface and are consumed by it --It needs to be clarified - could be taken as the phagocyte or the receptor itself.--JimmyButler (talk) 00:30, 29 March 2009 (UTC)

Yes, this needs to be clarified. Colin is working hard on the references at the moment and I don't want to generate any annoying edit conflicts (and I am on-call tonight). So I will address this point later. Graham Colm ^Talk 00:45, 29 March 2009 (UTC)

Thanks for being considerate wrt edit conflicts. Colin went to bed at 00:00 when his wife reminded him it was effectively 01:00. And someone small with a cold made sure I suffered the loss of that hour this morning. Colin°^Talk 07:29, 29 March 2009 (UTC)

Also, they could refer to phagocytes or bacteria. --Ettrig (talk) 06:38, 29 March 2009 (UTC)

One other then ... A clue to the origins of phagocytes is given by amoebae. The plural is important. Did it provide a single insight to the possibility of multiple origins or is it multiple lines of insight to a single origin? "Insights to the origin of... or Insight to the origins of.., or (lol) Insight to the origin of ... did I get them all? Perhaps drop "A clue" and substitute with Insight(s).

--JimmyButler (talk) 00:30, 29 March 2009 (UTC)

I chose this expression after much thought. They provide a clue—it's as simple as this. The rest of the question is lost on me, sorry. Graham Colm ^Talk 01:08, 29 March 2009 (UTC)

• Pathogen evasion and resistance: Earlier I queried whether "Signalling disruption" should be a sub-section but Graham doesn't think it should. That's fine but the section-lead still says "These survival strategies often involve...disrupting..cell signalling". I suppose the 2nd and 3rd methods of "avoiding contact" cover that. But is this signalling disruption more important that any of the other methods (such as hiding, avoiding engulfment, or killing) that it should be highlighted here and said to be "often"? The answer may well be yes, but I wanted to check as this fact was added after the section had been composed. Colin°^Talk 07:58, 29 March 2009 (UTC)

I have changed my mind and added a small section. I don't think that there is any hierarchy as such—each pathogen has its own "preferences". Graham Colm ^Talk 10:05, 29 March 2009 (UTC)

• Snot: I'm fairly sure it is a myth that snot turns green and thick due to a bacterial infection as this happens with a normal cold. The article doesn't have a lot to say about viruses, mentioning them twice: macrophages produce a molecule that kills "cells infected by viruses" and that lymphocytes (not phagocytes) produce antibodies that prevent cells being infected by viruses. So, during a viral infection, it appears phagocytes can kill infected cells and presumably eat the dead infected cells afterwards. Do other things kill virus-infected cells? Do phagocytes kill viruses that aren't inside cells? My guess is they don't notice them because they are too small. Could we say a little more about the role (even that it is a minor one if that is the case) of phagocytes wrt viral infections. Colin°^Talk 11:29, 29 March 2009 (UTC)

The innate immunity, i.e. phagocytosis, is not particularly good at dealing with viruses. In fact, it has been argued, in Delves and Sompayrac for starters, that the adaptive immune system evolved to defend us against these little bastards. Your are right about phagocytes mopping up after wards, but it is the lymphocytes that control virus infections. So, not really part of this article as such. But your are right. Some readers will wonder about viruses, so the article needs to mention them more, if only to say that phagocytes can't handle them alone. This will not be difficult to add and I will write it today. With regard to green snot during a viral infection—secondary bacterial infections, opportunistically infecting the damaged tissues, are no doubt to blame. Graham Colm ^Talk 12:07, 29 March 2009 (UTC)

Oh, so it is not a myth? Are we just told that these days to stop us asking for unnecessary antibiotics for infections that will clear up anyway? Colin°^Talk 12:38, 29 March 2009 (UTC)

PS, you may recall that in meningitis we wrote that the differential diagnosis of bacterial and viral infections is made by observing the phagocytes in CSF in the former and lymphocytes in the latter. Graham Colm ^Talk 12:18, 29 March 2009 (UTC)

Yes, it will help to indicate that these guys are good for some things but not everything. Colin°^Talk 12:38, 29 March 2009 (UTC)

Re: this edit. There's a comma after the day in US dates, before the year. And one of your access dates is ISO. I won't fix it because you're fiddling there too. Colin°^Talk 12:50, 29 March 2009 (UTC)

Evolutionary relation to amoeba

The article currently says phagocytes are evolutionarily related to amoeba. It also points out some similarities. Does this mean (1) they have evolved in similar ways; (2) animals have evolved from amoeba and retained the amoebic characters in the phagocytes; OR (3) phagocytes stem from an incorporated ameoeba (like mitochondria from cyanobacterium)? I think that (1) is true, but that most readers will interpret this as (2). Against (2) I would hold the fact that animals stem from choanoflagellates. --Ettrig (talk) 14:05, 29 March 2009 (UTC)

The article does not say that phagocytes are evolutionary related to, or imply that they have evolved from, amoebae. It does however suggest that the ancestors of phagocytes might have behaved similarly to free-living amoeboid cells. It is a common misconception that extant "simple" organisms have not evolved. The genes of human phagocytes are exactly the same as humans-they are identical. A comparison with the DNA of extant amoebae would show little relationship to human DNA. Mitochondria have their own DNA, and this supports the theory that they derive from early bacterial-like cells. So yes they have evolved in similar ways. Graham Colm ^Talk 14:34, 29 March 2009 (UTC)

The sentence that I think has these interpretations is A clue to the origins of phagocytes is given by amoebae. --Ettrig (talk) 14:57, 29 March 2009 (UTC)

Sorry Ettrig, I was busy with the FA nomination. I will tweak that sentence later, unless you have any suggestions. Graham. Graham Colm ^Talk 15:09, 29 March 2009 (UTC)

The section heading "Evolutionary origins" followed by "A clue to the origins of phagocytes is given by amoebae." could well also make someone quickly reading the text to assume what I've highlighted in bold. Perhaps there is some other way of starting or phrasing the section to avoid this potential confusion. Colin°^Talk 15:29, 29 March 2009 (UTC)

I have re-cast the opening of this section in light of these comments. Success? Graham Colm ^Talk 16:25, 29 March 2009 (UTC)

Sorry to keep nagging: Protection by phagocytes is common in animals and probably appeared early in their evolution. This defense mechanism can even be observed in the smallest of invertebrates. Dictyostelium discoideum, for example, is an amoeba that lives in the soil and feeds on bacteria. This single-celled animal engulfs bacteria by phagocytosis mainly through Toll-like receptors. In the current view, amoeba is not an animal. Qualifying with single-celled makes it un-false. But it is still misleading in this context, because it gives the impression that this is a retained primitive character. But we agreed earlier that most of the phagocytosing mechanisms have been reinvented in the animals. they have evolved in similar ways. --Ettrig (talk) 19:15, 30 March 2009 (UTC)

I have edited this section Ettrig. There is no evidence that that have or have not been reinvented, but I am happy with they have evolved in similar ways should you wish to edit the section accordingly. All the best, Graham. Graham Colm ^Talk 20:37, 30 March 2009 (UTC)

Couple of comments

Great job here, and I 'll likely support the FAC. But I'd like to make a few comments here that may help:

1. In "Phagocytosis" you need to make it clear that: "Within one minute the phagosome merges with either a lysosome or a granule to form a phagolysosome. The imprisoned bacterium is then submitted to a formidable battery of killing mechanisms,[24] and is dead a few minutes later" refers to neutrophils; macs and in particular DC are certainly not this fast!
2. The section on professional phagocytes deals a lot with the ultimate function of these cells and less with their role as phagocytes. I guess I'd expect to see more on how much these cells eat, which specific mechanisms they use to destroy stuff, ect. I think it is there in most cases, but gets lost in the function bit.
3. When you discuss the size of the cells I think it might help to say why size is important, i.e. can they eat more if they are bigger?, how big are bacteria/ other cells they are eating? is 21 microns really big? ect...
4. There are several human diseases caused by dysfunctional phagocytes. Including a sentence or two about them might help the reader understand how important phagocytes are; here is a brief description.

Just some thoughts for your consideration.--DO11.10 (talk) 19:40, 3 April 2009 (UTC)

Thanks, I was watching you edit the article and was so pleased that two experts stepped in today. Just some quick responses, for the time being, and in no particular order. Earlier, there was a section on dysfunctional phagocytes, which Eulemur and I wrote, but then we decided against it, because we were not satisfied with what we had written. The resource that you have directed us to will be very helpful in re-including a section on this. With regard to the somewhat more leisurely pace that dendritic cells enjoy their dinner; I was in two minds about including this, worrying about confusing the lay reader—am I right in thinking they can spend a day eating? I understand what you are saying about the pros and how we have focused perhaps too much on their later functions, such as antigen presentation, and I will try to redress the balance more towards their initial phagocytosis and killing. And, about size, yes it is important to give an idea of the sizes of their meals and I will have a go a this. This will keep me busy, enjoyably so, in the morning. Thanks for all this food for thought :-) and your expert guidance. We are very grateful to you. Graham. Graham Colm ^Talk 20:00, 3 April 2009 (UTC)

I've no doubt that a DC could spend a whole day eating (macrophages are the real gluttons though), but the more important point is that they don't fully digest as fast. This is probably related to why DC are the best APC. I guess I'd just somehow (?) try to make it clear that processing occurs at different rates in different phagocytes. While you have a go at my suggestions I hope y'all won't mind if I make some changes. These are suggestions though, feel free to revert anything you don't like. --DO11.10 (talk) 20:33, 3 April 2009 (UTC)

Thanks for helping DO11.10. Just to say, from a lay-persons POV, that saying "processing occurs at different rates in different phagocytes" would leave me unsatisfied. In contrast, your colourful discussion on leisurely vs hurried eating/digestion was very interesting. I'd love it if you guys could find a way to give the details and retain some of the entertaining metaphors and adjectives within the encyclopaedic tone. Colin°^Talk 20:49, 3 April 2009 (UTC)

This is just to acknowledge that I have read this very entertaining and interesting discussion. I look forward to writing a little more on these fascinating cells in the morning. Thanks guys. Graham. Graham Colm ^Talk 21:25, 3 April 2009 (UTC)

Agreed. How's this: I have seen a single macrophage eat six (!!) 15 micrometer latex beads, which just sit there because the macrophage can't digest them. Or ones that stuff themselves so full of zymosan that the cytoplasm looks like just the briefest of a halo around cell and the nucleus has been pushed way, way out to the very edge of the cell. Or that when macrophages eat too much they actually look foamy under the microscope. Makes DCs look like dainty princesses of the phagocyte world. I can't help but think that if they put that kind of stuff in the "respectable" literature science would be so much more interesting. As an unfortunate side effect of the utter bore-osity impinged upon me I'm not terribly good at tossing in entertaining metaphors where it counts. --DO11.10 (talk) 22:23, 3 April 2009 (UTC)

Yes you are—and it would count here—but I suggest sticking with the iron filings and the magnet. I have seen dendritic cells "take on" huge, compared to them ( but not so huge as 15 micron latex particles) infected enterocytes. As for bore-osity, I am sure you understand how I have to moderate my metaphors in my virus articles. I am so often tempted to write that viruses are more highly evolved than us. But, this is an encyclopedia and we have WP:NPOV. Graham. Graham Colm ^Talk

NPOV, pashaw... The Truth.--DO11.10 (talk) 23:00, 3 April 2009 (UTC)

You misunderstood my irony. I am absolutely sure it is the truth. No doubt at all. Sorry for the misunderstanding. G. Graham Colm ^Talk 23:08, 3 April 2009 (UTC)

Ohh, I just happened across this. Fascinating! A bunch of good stuff here and it seems like it qualifies as an WP:RS. Colin?--DO11.10 (talk) 23:00, 3 April 2009 (UTC)

Are you asking if I think it is reliable? I'm not sure. The book's focus (Nanomedicine) seems to be an area the author is (or considers himself to be) a pioneer so my feeling is it might not be reviewed as thoroughly, especially for aspects less important to the message (such as basic immunology). The emphasis in that section seems to be phagocyte interaction with nanoparticles, which is perhaps not so relevant for our basic article on phagocytes, despite being interesting in itself. Colin°^Talk 20:07, 4 April 2009 (UTC)

I was. Thank you for your analysis. I won't use it, on the safe side. Graham has made some fine revisions and so I doubt it will be needed anyway.--DO11.10 (talk) 04:39, 7 April 2009 (UTC)

Evolution, again

Protection by phagocytes is common and probably appeared early in their evolution. => ...in the evolution of animals. (?) --Ettrig (talk) 14:22, 4 April 2009 (UTC)

Thanks for spotting that Ettrig, and BTW you are allowed to edit the article :-) Graham Colm ^Talk 14:37, 4 April 2009 (UTC)

B Lymphocytes as APCs?

When I was in grad school, the prototypical antigen-presenting cell was the naive B lymphocyte. Doesn't that make them professional phagocytes? I know they have opsonin binding (membrane bound Ig) and they have MHCII. In fact, isn't phagocytosis and antigen presentation by B cells necessary to develop a T-cell mediated antibody response? I know immunology moves pretty fast, so I could see definitions changing.173.8.220.209 (talk) 18:58, 6 August 2009 (UTC)

• All of the above is true, apart from phagocytosis. My understanding is that B cells are "selected" by their cognate antigen, are activated and subsequently proliferate clonally. The antigens that they present to the other cells of the immune system are not derived from phagocytosis as such, these cells take in small antigens—fragments of bacteria for example—bound to the B cell receptor, then process and present them. Their ability to kill by engulfing is very poor, hence their lack of "professional" status. Thanks for an interesting question, which made me think. Graham Colm ^Talk 20:20, 6 August 2009 (UTC)

• • Thanks for the reply, Graham. I guess that the major determination for identification of proffessional phagocytes would be the Fc or Complement receptors? Two things: first, Mast cells? Do they even internalize anything? I thought they just degranulated upon crosslinking of their high-affinity FcE's. Second, check out this link: http://www.ncbi.nlm.nih.gov/pubmed/19494270 . Note, the authors point out that the B cell doesn't kill the Salmonella, but it does internalize it and remove antigens for presentation. Interesting stuff. I miss immunology.173.8.220.209 (talk) 22:33, 6 August 2009 (UTC)

• • • Thanks again, this time for alerting me to this interesting paper, which I hadn't read. With regard to mast cells, as well as being potent poisoners of parasites, they can phagocytose opsonised bacteria.[1] Unlike lymphocytes, they can kill, which is not surprising given all those granules. Clearly, "professional" and "non-professional" are useful labels, but the ability of all the fascinating cells of the immune system to multi-task cannot be overlooked. Graham Colm ^Talk 17:48, 7 August 2009 (UTC)

• • • • I just checked my textbook on immunobiology (Janeway et al), according to which "Dendritic cells, macrophages, and B cells are often known as professional antigen-presenting cells". However, it also explains that B cells are not major phagocytes despite their ability to specifically ingest large amounts of antigen recognized by the BCR. This is mainly because of their extremely narrow specificity and the fact that they do not migrate into tissues like macrophages and dendritic cells love to, and thus less often come face to face with large numbers of pathogens, particularly intact ones. B cells also lack broad-specificity coreceptors that facilitate ingestion of entire microorganisms in macrophages and neutrophils (the latter of which are professional phagocytes but not professional APCs). So those phagocytes can ingest all sorts of things (and dendritic cells can go nuts with macropinocytosis), while B cells are basically limited to just the one antigen their receptor is specific for. So I think it makes sense to exclude B cells from the group of professional phagocytes, while including them in the group of professional APCs. Sakkura (talk) 14:28, 13 August 2009 (UTC)

Copyedit question

I'm puzzled by the following from Phagocyte#Phagocytosis: "Opsonin receptors increase the phagocytosis of bacteria that have been coated with complement or IgG antibodies." Does it mean "complement antibodies or IgG antibodies", or is "complement" a thing in its own right? Also, "Complement is the name given to a complex series of protein molecules found in the blood that destroy or mark cells for destruction." This seems to be saying that the word "complement" in this context, all by itself, means the series.

Complement, or more accurately the complement system, is not an antibody. It is composed of about 20 different proteins that work together to kill bacteria and other invaders. It also stimulates other cells of the immune system into action. The complement system is very old and probably predates antibodies. When these proteins are circulating separately in the body they are called complement proteins. During an infection these proteins come together on the surface of the invader and, along with other activities, punch a hole through the invader's cell membrane. For short these proteins, particularly when they have been activated and coalesce, are simply called "complement". Graham Colm ^Talk

Also, in Phagocyte#Non-professional_phagocytes, "Fibroblasts, for example, only make ineffective attempts to ingest foreign particles." Is "ineffective" the right word? If their attempts are ineffective, they are not phagocytes at all, right? --Milkbreath (talk) 02:35, 30 August 2009 (UTC)

"Ineffective" was the best word I could come up with. The main role of fibroblasts is the formation connective tissue, they can ingest some foreign matter, but are feeble and unpredictable at this. They can engulf but because phagocytosis is far from their prime function as it is currently understood, they are non-professional phagocytes. Graham Colm ^Talk 09:47, 30 August 2009 (UTC)

I've changed the complement sentences to read, "Opsonin receptors increase the phagocytosis of bacteria that have been coated with immunoglobulin G (IgG) antibodies or with complement. "Complement" is the name given to a complex series of protein molecules found in the blood that destroy cells or mark them for destruction." I've changed the fibroblast sentence to read, "Fibroblasts, for example, which can phagocytose collagen in the process of remolding scars will also make some attempt to ingest foreign particles." I hope that this is correct, but there seems to be a problem with the reference note. --Milkbreath (talk) 11:46, 30 August 2009 (UTC)

Thanks for your help with the article. After a lot of searching I have found a better citation. Graham Colm ^Talk 13:43, 30 August 2009 (UTC)

Hey, don't thank me, it's my article, too. By the way, reference 117 is broken. Perhaps you're more familiar with that aspect of this article and could more easily fix it than I could. --Milkbreath (talk) 18:18, 30 August 2009 (UTC)

Yes, that was my doing. I have fixed it for the time being. I shall format the reference, and the new one I added earlier today, properly later when I have the time. Will you accept my thanks for your being a valued collaborator? Graham Colm ^Talk 19:18, 30 August 2009 (UTC)

Aw, shucks ... OK. But all I did was pick a few nits off it. Nice job, guys. --Milkbreath (talk) 19:52, 30 August 2009 (UTC)

Inconsistence

Hello. Can't understand the compatibility between the initial definition: "Phagocytes are the white blood cells that protect the body by ingesting (phagocytosing) harmful foreign particles" and the erythrocytes and other stuff shown later in the article. --3coma14 (talk) 07:21, 12 May 2010 (UTC)

Bacteria

such as bacteria, that are not normally found in the body.

Its wrong, bacteria in normal can be found in body (such us, in the intestine)--Meddoc13 (talk) 17:19, 12 September 2010 (UTC)

You are quoting out of context. A fuller quote is "the professional phagocytes have molecules called receptors on their surfaces that can detect harmful objects, such as bacteria, that are not normally found in the body." It is harmful objects (including some bacteria) that are not normally found in the body, not bacteria in general. Sakkura (talk) 18:28, 12 September 2010 (UTC)

Exemplary article

I hope this isn't inappropriate, but I feel moved to compliment the authors of this well-written and -organized article. Too many scientific and technical articles in Wikipedia are incomprehensible to a general audience. A great deal of effort and thought obviously went into making this difficult subject understandable to non-scientists. It is very much appreciated.Djxb2001 (talk) 01:24, 16 January 2012 (UTC)

On behalf of all the editors that worked on this article, thanks! Graham Colm (talk) 06:54, 16 January 2012 (UTC)

Errors in content

While I agree with above that the article is well written, it unfortunately contains numerous errors in content. Mast cells are not phagocytes, despite the article. Eosinophils are but this has not been included. I feel this page has strayed from the scientific, especially in so much as not being accurate to current knowledge, and while it may be a pleasure to read, lacks academic rigueur and needs review by an expert in the area rather than high school students. I'm not a usual contributer (other than financially) and apologies as not being a registered user. Dr Anthony Bragg — Preceding unsigned comment added by 14.203.226.165 (talk) 14:43, 7 September 2014 (UTC)

You must not assume that the article was written entirely by high school students - it wasn't and I do have expertise in the area. I have a sources to support the inclusion of mast cells: "Urb M, Sheppard DC (2012) The Role of Mast Cells in the Defence against Pathogens. PLoS Pathog 8(4): e1002619. doi:10.1371/journal.ppat.1002619" and the chapter in Ernst and Stendal that is cited in the article, but cannot find a reliable source to support the inclusion of eosinophils as phagocytes in vivo. If you can point me to one, I would be happy to include them. I am interested in the other "numerous errors". Would you have the time to be more specific? With regards to "academic rigueur", this is an encyclopaedia article, not a scientific review. I have been careful to avoid jargon and to strive for accessibility for the lay reader. Graham Colm (talk) 16:09, 7 September 2014 (UTC)

Dr Bragg, I mostly wanted to say you have no need to apologize for not being a regular contributor! There's no rule that you must be one. Also, although, contributions of knowledge must be accompanied by good sources. If one good source contradicts another, that's no problem. In such a case, we just summarize both but then explain what the scientific consensus is {{as of}} the time of the most recent applicable source. As you know, experts often disagree with each other! Cheers, —Geekdiva (talk) 00:40, 23 February 2016 (UTC)

Help request: Inconsistent grouping of technical terms

Summary of help requests:

• Please verify my analysis and revision in § CGD statement is correct. (It ties into this article & others.)
• "Are" vs. "include" vs. "are the most important" are not trivial distinctions! They should not be used to link the same technical terms in different sentences. Please discuss this in § Drawing correct boundaries and then please edit where necessary in this article and ideally subject-wide.
• Sorry I often can only point some things out. Due to real-life limitations, I might not make it back here, so I have to do a complete data-dump. Thanks in advance.

CGD statement

While editing Chronic granulomatous disease (CGD in this thread), I found the illness described as:

...a diverse group of hereditary diseases in which certain cells of the immune system have difficulty forming the reactive oxygen compounds (most importantly the superoxide radical due to defective phagocyte NADPH oxidase) used to kill certain ingested pathogens.

I was just there to tidy up a few things while skimming the article, and I'm not a medical expert, so I'm extra careful when changing things. I wanted to change the parenthetical statement to (additions in italics):

...(most importantly the superoxide radical due to a defective phagocyte called NADPH oxidase)

However, the NADPH oxidase article's intro says,

The NADPH oxidase...is a membrane-bound enzyme complex that faces the extracellular space. It can be found in the plasma membrane as well as in the membranes of phagosomes used by neutrophil white blood cells to engulf microorganisms.

So, (the? is "the" needed?) NADPH oxidase is an enzyme complex that can be found in phagosomes used by (or within?) a type of phagocyte. In other words, in the unclear CGD phrase, "phagocyte" was modifying NADPH oxidase to show what type of NADPH oxidase was involved. ... _Right? Therefore, I think the following is correct (additions in italics):

...(most importantly the superoxide radical, caused by defective NADPH oxidase, an enzyme complex that can be found in phagocytes)

Conclusions

1. . I'm going to make this change in the CGD article. Please change it if it's incorrect, but please don't just revert it; you can see how confusing I found it as a layperson with one class of college biology a while back.
2. . Anything above that I questioned as an aside is a style issue and should be standardized at least within each article, and hopefully across article in the same category. Does this WikiProject have a style-guide keeper? Thanks!

Drawing correct boundaries

I was going to add the following Clarify template text to the article at Phagocyte § Professional phagocytes:

Phagocytes of humans and other jawed vertebrates are divided into "professional" and "non-professional" groups based on the efficiency with which they participate in phagocytosis. The professional phagocytes are the monocytes, macrophages, neutrophils, tissue dendritic cells and mast cells.

However, when trying to understand phagocytes vs. phagosomes vs. white blood cells, &c., by drawing a Venn diagram of them in my head, I couldn't get the boundaries right.

• Obviously, the articles I linked to in § CGD statement (and others I looked at on related topics) are full of jargon to the degree that each of them could stand improvement. Jargon is unavoidable in technical areas, but can be reduced by clearer phrasing and by pushing more complicated sub-sections towards the end, so people can read from the top down to the level of their comfort.

• But in this case as in the example I gave above, the main problem I had in figuring out what was what is subtle changes in wording when these technical words were discussed. Even small changes can have large implications. There are HUGE differences if terms "are" or if they "include" or if they "are the most important of" something(s) else.

I kept running into this ambiguity between sentences and other styles of info such as tables. I unfortunately didn't think to keep track of where I saw it, so someone would have to start from almost-scratch. Statements like this should be verified article-wide at minimum, and cross-article within related articles as an ideal.

Sincere thanks! Hope this helps. (This always happens! I decide to chase down one little Wikipedia string and I unravel the whole sweater of an edit to-do list! Heh.) —Geekdiva (talk) 23:14, 22 February 2016 (UTC)

What on earth are you waffling on about? Graham Beards (talk) 14:57, 17 March 2016 (UTC)

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