Talk:Antibody

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WikiProject Echo has identified Antibody as a foreign language featured article. You may be able to improve this article with information from the Polish language Wikipedia.

Antibody is a current good article nominee. If you have not contributed significantly to this article, feel free to evaluate it according to the good article criteria and then pass or fail the article as outlined on the candidates page. Nomination date: 2007-03-30

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 1 From the article 2 Antibody function is a bit vague/poorly written 3 Difficult to Understand 4 Number of antibodies 5 Antibodies and immunoglobulins 6 External Links to Antibody Research 7 IgM hexamer formation? 8 Sizes of antibody fragments 9 Why "Y" shaped 10 GA nomination

[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)

[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)

[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. 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)

"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)

[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)

[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)