Talk:Antibody

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    Some things I may tackle but feel free to help or comment!

    this is started, at least
    • A diagram is needed in the Immunoglobulin diversity section - perhaps showing location of genes on chromosome or mechanism of recombination.
    done - V(D)J recomb, and class switch recomb diagrams added
    • Still need to clarify affinity v. avidity. think this is done
    • Need to fix consistency. Someone chopped out much of the info from non-humans (i.e. all the heavy chain stuff), but left a little bit in (the light chain stuff) - should it all go or should some stuff come back?

    Ciar 21:42, 20 May 2007 (UTC)


    The page history of this talk page prior to January 7 2005 was originally at Antibodies&Contributions which was felt to be an inappropriate title. The content had previously been merged with the Antibody article. Angela. 10:27, Jan 7, 2004 (UTC)

    Contents

    [edit] From the article

    An anon deposited this in the article body:

    Some immunoglobulins are known to catalyze the formation of ozone from water, presumably to kill pathogenic agents in its vicinity. The catalytic mechanism for this process is unknown.

    Does anyone know if this is correct? Google gives some high-ranking results, but I wonder if this isn't too tentative to make it into an encyclopedia. The first reference I can find is from 2003 (PMID 12967665). JFW | T@lk 11:17, 27 Sep 2004 (UTC)

    I would have though that would be more about the "reactive oxygen" (superoxide etc) system in endolysosomes within the actual phagocytic cells, not directly from the Ig.--KX36 16:09, 14 February 2007 (UTC)

    A science magazine article (http://www.sciencemag.org/cgi/reprint/298/5601/2195.pdf) says the ozone is produced from singlet molecular oxygen (that can be produced by neutrophils) and water. Not from water alone. Narayanese 16:19, 13 May 2007 (UTC)

    [edit] Antibody function is a bit vague/poorly written

    Would anybody object to me replacing it with something a whole lot clearer and more technical (Biochemistry perspective)?

    I'm a tad busy, but will update in a couple of days?

    --Hoju 12:13, 3 Nov 2004 (UTC)

    [edit] Difficult to Understand

    Hello, as someone who has only an "average" understanding of chemistry and medicine, I found that this article was too technical. While I liked the indepth explanations, I simply could not understand the paragraphs included under "Definition", "Structure of the antibody" and "Isotypes". I hope I did not offend the author(s) of this article -- just keep it safe for the non Ph.D.s and MDs! :)

    Nobody said biology was simple. However, if something is not understandable, you can ask questions (be specific) and the authors or me at least will detail it further so the article will gradually become more readable. Anyway, if someone has a clear idea how to make this article more simple while at the same time keeping it accurate and all the facts included, just feel free to do it. --Eleassar777 23:52, 23 Feb 2005 (UTC)
    It is difficult to understand, more difficult than it needs to be. This is probably a function of cutting and pasting sentences from other resources like http://www.absoluteastronomy.com/encyclopedia/a/an/antibody.htm. There are also a few contradictions, for example "The monomer is composed of two heavy and two light chains" - an unusual use of the word monomer. When I have some time I'll clean this article up a bit.
    You are welcome to do so and thank you for having come here. Yes, perhaps this is an unusual use of the word monomer, however it is generally used in such a context. The other thing I wish to point out is that all the resources I used were offline resources, that are stated below, and some text (from the page you give) was written before I came here.
    Also, please use your signature. You create it with three tildes ~~~). Four tildes ~~~~ gives also the time and date you came here. Thanks. --Eleassar777 09:08, 24 Feb 2005 (UTC)

    The immune system is a fascinating subject, but IMHO - this article is way too complicated for an encyclopedia. Also, it doesn't seem to link up with other parts of the immune system (unless it's buried and I missed it...) I remember understanding these processes backwards and forwards in college - but when I read this - I'm like, huh? Did something change in the last 3 years? I know there were some advances but this is really hard to absorb. I'd edit it myself but it's over my head at the moment. The immune system can be made much more easy to understand... like any subject. Even nuclear physics can be explained simply...and that involves math!

    [edit] Number of antibodies

    Is there information on how many different antibody molecules humans and other mammals (or even other animals) can express. I've got a text book where it says that mammals can produce 10^6 to 10^8 different antibodies. --EnSamulili 16:24, 11 May 2005 (UTC)

    Not very precise, uh? VDJ recombination produces a very large number, but I would avoid "mammals can produce 10^6 to 10^8 different antibodies". I would say: "Estimates differ on the number of possible antibodies that a mammal can produce. Some maintain it is 1,000,000, while others think it may be 100 times as much". JFW | T@lk 20:01, 11 May 2005 (UTC)
    Reasonable accurate figures can be calculated, and come out to about 10^16 possible antibodies in total. However the average human has about 10^12 B-cells, so this is the limit of individual antibody production. There is enough information on this to form a section on how antibodies generate diversity. I'll probably get round to this at some point --|Spaully 12:21, 1 February 2006 (UTC)
    There was a proof in one of my lectures that the VDJC recombination system can form ">10^8 different hypervariable regious (CDR's)". Some clever chap has worked out that that's a bigger number than the possible number of epitopes.
    Light chain has 1C, 35V, 5J; 3 different ways V and J join, 2 different light chains; makes 1050 combinations.
    Heavy chain has 1C, 45V, 6J, 20D, 3 different ways V and D join, 3 different ways D and J join; makes 48600 combinations.
    Now here's the dodgey bit. Making the assumption that all light chains can pair with all heavy chains, which isn't true, there's 51,030,000 combinations. Affinity maturation (somatic mutation) is estimated to roughly double this value to 10^8.
    I don't know how you got values of 10^16 antibodies and 10^12 B cells.--KX36 17:06, 14 February 2007 (UTC)

    [edit] Antibodies and immunoglobulins

    Are there any antibodies that are not immunoglobulins? --Eleassar777 12:41, 18 May 2005 (UTC)

    Not as far as I'm aware. JFW | T@lk 20:45, 3 January 2006 (UTC)
    Antibody and Immunoglobulin are synonyms, they are literally the same thing. Philmcl 11:58, July 11 2006 (EST)

    According to Stedman's Medical Dictionary vol 27 (immunoglobulin), there are some pathologically-produced immunoglobulins that do not function as antibodies, but I'm not sure how significant this fact is. Drangscleaner 18:23, 17 July 2006 (UTC)

    Very interesting. For reference, here's the link: Stedman's/LWW 1528225. And here's the key sentence: "Antibodies are Ig's, and all Ig's probably function as antibodies. However, Ig refers not only to the usual antibodies, but also to a great number of pathological proteins classified as myeloma proteins, which appear in multiple myeloma along with Bence Jones proteins, myeloma globulins, and Ig fragments." --Arcadian 18:57, 17 July 2006 (UTC)

    Don't worry - all Ig's ("immunoglobulins") are antibodies and vice versa. All are produced by B-cells. --GeHa 21:42, 21 July 2006 (GMT)

    Immunoglobulins are also produced by Plasma Cells (which in turn are the progeny of activated B-cells). I recently read a textbook (Basic Immunology, Abbas et al) that stated that more than half of the antibody present in the human body are produced by plasma cells. However, the experts seem to disagree on this point. Andbir (talk) 09:50, 20 May 2008 (UTC)

    Ahhh, but as you say, plasma cells are still B cells that have become huge due to their large scale production of antibody - they need all the space to make and process the protein! As for the confusion over Ig's above, immunoglobulin was a name given to describe an antibody when it was first characterized many years ago (based on its biochemical properties). Other proteins can be referred to Ig-like proteins or immunoglobulin superfamily (IgSF) proteins, since the have the same structural features (Ig-domains) as antibodies (the first known Igs), but they are not true "immunoglobulins" stricto senso. These other IgSF proteins are produced by cells other than B cells. ~ Ciar ~ (Talk to me!) 15:36, 20 May 2008 (UTC)

    Some cancers are derived from B-cells ("myeloma"), and as these cells expand far beyond the usual for a normal B-cell (as cancers do), these may produce the one Ig that B-cell coded for in immense amounts. Normally, any individual Ig is only produced in large amounts when it has particular relevance - say, an anti-viral antibody during an active infection. However, as the continued growth of the B-cell "gone wild" is not being being driven by a productive immune response, the massive amounts of the immunoglobulin it is pouring out may or may not be binding anything known/useful. Perhaps this lead to the statement you quoted above. Antibodies reacting to self proteins are called autoantibodies and are thought to be driving certain diseases (Multiple sclerosis, rheumatoid arthritis, lupus...). These contribute to disease activity and are thus considered pathogenic/harmful. The immunoglobulins produced by the myelomas referred to here probably don't do anything harmful in their own right, but are secundary to the actual problem (i.e. cancer). Thus, they should not be considered pathological in the sense that they cause disease - they are merely symptoms of the underlying disease --GeHa 21:42, 21 July 2006 (GMT)

    The immunoglobulins produced by myelomas are very harmful for the patient mainly causing serious damage to the kidneys leading to renal insufficiency in late stages. Kischel 23:07, 22 September 2007 (UTC)

    "Antibody" is a functional definition, something that binds antigens. "immunoglobulin" is a structural one. It could probably be said that T-cell receptors and MHC's are antibodies and although they contain immunoglobulin domains (as do many proteins), are not themselves immunoglobulins. I would also agree that an immunoglobulin without activity on an antigen is not an antibody--KX36 17:21, 14 February 2007 (UTC)

    T-cell receptors and MHC's do interact with peptides while antibodies interact with molecular structures which are considerably larger. Antibodies also belong to a different section of the immune system with its own effector mechanisms. I would therefore strongly suggest not to use the term antibody for T-cell receptors or MHC molecules. Kischel 23:07, 22 September 2007 (UTC)

    [edit] Gamma vs. all

    Arguably, not all immunoglobulins (antibodies) are gammaimmunoglobulins? Andbir (talk) 09:50, 20 May 2008 (UTC)

    [edit] External Links to Antibody Research

    [Antibody Sources, Suppliers, and Protocols] Suppliers of Custom Antibodies, and Antibodies by Field. Protocols for Western Blotting, Immunoprecipitationm and Antibody Microarrays.

    Hardly an authoratitive resource, supported by Google ads. JFW | T@lk 20:45, 3 January 2006 (UTC)
    • [Collected resource for antibody protocols]
    I removed the links from these sources since they represent spam that is not allowed in wikipedia (and I'm guessing that includes hiding advertising on talk pages). See [[1]] Ciar 16:15, 16 March 2007 (UTC)

    [edit] IgM hexamer formation?

    Does IgM ever adopt the hexemeric form under normal, non-disease process conditions? In know it can occur in some lymphomas, but thought the pentemer form was by far the most common. MarcoTolo 03:55, 4 February 2006 (UTC)

    IgM can only form hexamers without a J chain. Janeway ('05) describes the formation as 'occasional'. Will edit. Tricky 15:35, 10 March 2006 (UTC)

    [edit] Sizes of antibody fragments

    the picture's caption says "An antibody digested by papain yields two fragments, two 50 kDa Fab fragments and one 50kDa Fc fragment."

    This is only true for certain Ig's. IgE and IgM have epsilon and mu heavy chains which have 5 domains, not 4; and as such, would have 75kDa Fc fragments. Also "two fragments; 2 Fab and a Fc" would be 3 fragments or 2 different fragments. Also, if you're saying the exact number of fragments for an antibody (rather than the number of different fragments), whether it's a monomer, dimer or pentamer would make a difference. I suggest this is rewritten.--KX36 17:12, 14 February 2007 (UTC)

    [edit] Why "Y" shaped

    Just quick question - why are antibodies "Y" shaped. From a layman's perspective, it seems to me that only one half of the Y is need for an antibody to work.

    That is, it seems to me that only one receptor on one of the arms is needed to binding to the antigen.

    Does two arms result in a simple doubling the number of binding sites, so as to double the number of "capture site" per molecule, or is there something more subtle to it all?

    Thanks -- Quantockgoblin 17:11, 16 March 2007 (UTC)

    There's two quick answers, which I'm unclear how pertinent they'd be to the article, since they're essentially teleologic.
    1) Binding of bivalent immunoglobulins of multiple epitope specificities allows for the formation of immune complexes
    2) Activation of Fc receptors on effector cells (B cells, macrophages, etc.) may require cross-linking Jbarin 00:42, 7 May 2007 (UTC)

    -> A third comment should be added to the question: Working with single-chain antibodies – a form of antibodies modified by biotechnological means, which possess only one binding domain - one does observe a significant reduction in the strength of binding of the single-chain antibody to its antigen ias compared with the original antibody having two binding sites - This observation strongly suggests that the two binding sites are also needed to improve the strength of binding. Kischel 22:45, 22 September 2007 (UTC)

    [edit] GA nomination

    H'mmm, I'm thinking this article is a little bit weak on the refs. I'll try and add some in when I can....anyone else able to help push this up to standard?? Thanks, Ciar 23:46, 30 March 2007 (UTC)

    I'd be happy to help out, let me know if you need anything special. First on my list will be to find some GOOD external links, hopefully to discourage some of the spamming.--DO11.10 00:00, 31 March 2007 (UTC)

    As far as references go, this article is pretty good, for GA standard. I don't know how much you've done since 31 March, but it seems to be up to scratch. The only thing I am a little concerned about is the use of jargon in this article, however, as most of the jargon is blue-linked, that is OK for GA. The structure is consistent and well ordered. The lead section, while a little complex, does provide a suitable overview for the article.

    As for stability, I can see there have been a lot of vandalism on this page in the past few hours, but otherwise the page is pretty stable, so I'm happy with that. Obviously, some school somewhere is using Wikipedia as a resource.

    GA review (see here for criteria)
    1. It is reasonably well written.
      a (prose): b (MoS):
    2. It is factually accurate and verifiable.
      a (references): b (citations to reliable sources): c (OR):
    3. It is broad in its coverage.
      a (major aspects): b (focused):
    4. It follows the neutral point of view policy.
      a (fair representation): b (all significant views):
    5. It is stable.
    6. It contains images, where possible, to illustrate the topic.
      a (tagged and captioned): b lack of images (does not in itself exclude GA): c (non-free images have fair use rationales):
    7. Overall:
      a Pass/Fail:

    So, as you can see, I am happy to pass this article to GA. It contains a good amount of well-structured, reliably sourced information that would be useful to many users.

    If you want to take this article further, I would recommend trying to cut down on the amount of jargon used in the article and using simpler prose, for example "similar" instead of "analogous", to make it easier to understand. Don't go overboard though. Also, the lead section could do with some restructuring, perhaps to find a more suitable place for that second paragraph.

    I would strongly suggest you get a peer review of this article and try and get as many editors as you can to comment, so as you can see where to go from here, before making any major changes. Otherwise, well done! Smomo 14:44, 3 April 2007 (UTC)


    [edit] Redirection Issue

    When I get redirected from antibodies, the image at the top of the page is black and white. Is this an issue with Wikimedia in general?71.70.172.21 00:37, 7 May 2007 (UTC)

    By b&w I mean black and white. 71.70.172.21 00:38, 7 May 2007 (UTC)

    Never mind. It doesn't seem to be doing it anymore 71.70.172.21 00:39, 7 May 2007 (UTC)


    [edit] For safe-keeping

    Just trying to tidy up article following peer review so going to add/remove/move around stuff trying to get a good overall "big picture". Not sure the info below adds useful info to the antibody article so took it out for now...but didn't want to completely delete is....gonna pop it here for now if someone prefers it goes back in!

    In an experimental setting, enzymes can be used to cleave the antibody into Fc and Fab fragments.

    Enzyme Location of cleavage First fragment Second fragment
    papain at hinge region two Fab fragments Fc fragment
    pepsin below hinge region one F(ab')2 fragment Fc fragment
    The variable regions of the heavy and light chains can be fused together to form a single chain variable fragment (scFv), which is only half the size of the Fab fragment yet retains the original specificity of the parent immunoglobulin.[1]

    [edit] History

    I've noticed that a lot of reviewers want to see history sections in articles when they are proposed for the higher levels (!) so I put together a little mish-mash of history that I could find out there. I can't seem to make it flow though...any good copy-editors want to have a go?? Ciar 05:13, 6 June 2007 (UTC) Ciar 21:27, 20 May 2007 (UTC)

    Done. TimVickers 15:57, 6 June 2007 (UTC)

    [edit] Use of brand name

    Although it might be a very German concept - I do find the use of the brand name RhoGAM in the section about the Rhesus blood group slightly biased and therefore infringing on the guideline of neutral point of view. A general term for anti-Rhesus immunoglobulins should be used and the single reference to only one brand either deleted or expanded with other brand names. Kischel 23:29, 22 September 2007 (UTC)

    I agree.....and fixed it (hopefully!) Ciar 07:21, 23 September 2007 (UTC)

    [edit] Automatic addition of "class=GA"

    A bot has added class=GA to the WikiProject banners on this page, as it's listed as a good article. If you see a mistake, please revert, and leave a note on the bot's talk page. Thanks, BOT Giggabot (talk) 04:43, 10 December 2007 (UTC)

    [edit] Structure of antibodies

    "Each antibody has two large heavy chains H and two small light chains L."

    This sentence seems flawed to me as it is true only for monomeric isotypes. --Eleassar my talk 14:35, 11 March 2008 (UTC)

    I reworded the sentence. ~ Ciar ~ (Talk to me!) 05:30, 12 March 2008 (UTC)

    [edit] External link suggestion

    Dear writers, I would like to suggest a link to the article on antibody generation on openwetware. The article in question is a technical description of how a biologist would go about generating a new antibody. It may be of interest to the public to see how antibodies are not just a natural phenomena but also a technique in the lab. To researchers this would be an interesting link with a lot of added information. Please consider it. Best, --Jakob Suckale (talk) 14:03, 24 April 2008 (UTC)