Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Isotype ko canza aji shine tsarin ilimin halitta wanda ke faruwa bayan kunna kwayar B, wanda ke bawa kwayar damar samar da nau'ikan nau'ikan antibodies (IgA, IgE, ko IgG). An bayyana nau'ikan nau'ikan antibodies daban -daban, sabili da haka ayyuka masu tasiri, ta yankuna na dindindin (C) na sarkar immunoglobulin mai nauyi. Da farko, ƙwayoyin B na naïve suna bayyana IgM da IgD ne kawai na sel tare da yankuna masu alaƙa da antigens iri ɗaya. Kowane isotype an daidaita shi don aiki daban; sabili da haka, bayan kunnawa, ana iya buƙatar antibody tare da aikin IgG, IgA, ko IgE mai tasiri don kawar da antigen yadda ya kamata. Canjin aji yana ba da damar ƙwayoyin 'ya'ya daban-daban daga ƙwayar B mai aiki guda ɗaya don samar da ƙwayoyin cuta na isotypes daban-daban. Yankin da ke ci gaba da sarkar sarkar antibody ne kawai ke canzawa yayin sauya aji; yankuna masu canzawa, sabili da haka ƙayyadaddun antigen, ba su canzawa ba. Don haka zuriyar kwayar B guda ɗaya na iya samar da ƙwayoyin cuta, duk takamaiman antigen guda ɗaya, amma tare da ikon samar da aikin mai tasiri wanda ya dace da kowane ƙalubalen antigenic. Canza aji yana haifar da cytokines; isotype da aka samar ya dogara da waɗanne cytokines suke cikin yanayin ƙwayoyin B. Canjin aji yana faruwa a cikin sarkar jini mai nauyi ta hanyar hanyar da ake kira sake fasalin canza aji (CSR). Wannan tsari ya dogara ne akan abubuwan da aka kiyaye nucleotide, wanda ake kira sauya (S) yankuna, da aka samo a cikin DNA sama da kowane yanki na yau da kullun (ban da δ-sarkar). An karya DNA ta hanyar aikin jerin enzymes a yankuna biyu da aka zaɓa. Ana sake haɗuwa da yankin mai canzawa ta hanyar aikin da ake kira haɗuwa da ƙarshen ƙarshen (NHEJ) zuwa yankin da ake so (γ, α ko ε). Wannan tsari yana haifar da kwayar cutar immunoglobulin wacce ke sanya kwayar cuta ta wani nau'in daban.  Tambaya: Menene wannan tsari ya dogara da shi?
abubuwan da aka kiyaye nucleotide