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Rivi 22:
Immunoglobuliinit ('''Ig''') jaetaan [[isotyyppi|isotyyppeihin]] (luokkiin) niiden raskasketjujen vakiodomeenien mukaan. Isotyyppejä on viisi: [[IgG]], [[IgA]], [[IgM]], [[IgD]] ja [[IgE]]. Näitä vastaavat raskasketjut ovat γ, α, μ, δ ja ε.
{| class = "wikitable" style = "width:100%; float:right; font-size:90%; margin-left:15px"
|+ Nisäkkäiden vasta-aineiden isotyypit
| '''Nimi''' || '''Tyyppi''' || style="text-align:center;"| '''Kuvaus''' || style="text-align:center;"| '''Vasta-aineen kompleksi'''
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| style="text-align:center;"| [[IgA]] || style="text-align:center;"| 2 || Esiintyy [[limakalvo]]illa, kuten [[suoli|suolessa]] ja hengityselimissä. <ref>{{cite journal |author=Underdown B, Schiff J |title=Immunoglobulin A: strategic defense initiative at the mucosal surface |journal=Annu Rev Immunol |volume=4 |issue= 1|pages=389–417 |year=1986 |pmid=3518747 |doi=10.1146/annurev.iy.04.040186.002133}}</ref> Also found in saliva, tears, and breast milk.|| rowspan="5" |[[File:Mono-und-Polymere.svg|170px|Some antibodies form [[protein structure|complexes]] that bind to multiple antigen molecules.]]
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| style="text-align:center;"| [[IgD]] || style="text-align:center;"| 1 || Functions mainly as an antigen receptor on B cells that have not been exposed to antigens.<ref name=Geisberger>{{cite journal |author=Geisberger R, Lamers M, Achatz G |title=The riddle of the dual expression of IgM and IgD |journal=Immunology |volume=118 |issue=4 |pages=060526021554006–– |year=2006 |pmid=16895553 |doi=10.1111/j.1365-2567.2006.02386.x |pmc=1782314}}</ref> It has been shown to activate [[basophils]] and [[mast cells]] to produce antimicrobial factors.<ref name=Chen>{{cite journal |author=Chen K, Xu W, Wilson M, He B, Miller NW, Bengtén E, Edholm ES, Santini PA, Rath P, Chiu A, Cattalini M, Litzman J, B Bussel J, Huang B, Meini A, Riesbeck K, Cunningham-Rundles C, Plebani A, Cerutti A |title=Immunoglobulin D enhances immune surveillance by activating antimicrobial, proinflammatory and B cell-stimulating programs in basophils |journal=Nature Immunology |volume=10 |issue=8 |pages=889–898 |year=2009 |pmid=19561614 |doi=10.1038/ni.1748 |pmc=2785232}}</ref>
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| style="text-align:center;"| [[IgE]] || style="text-align:center;"| 1 || Binds to [[allergens]] and triggers [[histamine]] release from [[mast cells]] and [[basophil]]s, and is involved in [[allergy]]. Also protects against [[parasitic worm]]s.<ref name=Pier/>
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| style="text-align:center;"| [[IgG]] || style="text-align:center;"| 4 || In its four forms, provides the majority of antibody-based immunity against invading pathogens.<ref name=Pier/> The only antibody capable of crossing the placenta to give passive immunity to fetus.
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| style="text-align:center;"| [[IgM]] || style="text-align:center;"| 1 || Expressed on the surface of B cells (monomer) and in a secreted form (pentamer) with very high [[avidity]]. Eliminates pathogens in the early stages of B cell mediated (humoral) immunity before there is sufficient IgG.<ref name=Pier/><ref name=Geisberger/>
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'''IgG''' on immunoglobuliineista yleisin. Se esiintyy [[monomeeri]]senä. IgG voi kulkeutua [[istukka|istukan]] läpi ja suojella [[sikiö]]tä, kun sen oma [[immuunijärjestelmä]] ei vielä ole kehittynyt.
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