20xx年醫(yī)學(xué)專題—-免疫原和免疫球蛋白-在線瀏覽
2024-11-04 07:16本頁(yè)面
【正文】 ntigenic epitope,Structure of a complex between a peptide derived from HIV protease and an Fab fragment from an antiprotease antibody (left) and comparison of the Fab structure before and after peptide binding (right). In the right panel, the red line shows the structure of the Fab fragment before it binds the peptide and the blue line shows its structure when bound. There are significant conformational changes in the CDRs of the Fab on binding the antigen. These are especially pronounced in the light chain CDR1 (L1) the heavy chain CDR3 (H3).,可變區(qū)〔V區(qū)〕恒定(h233。ng)區(qū)〔C區(qū)〕,Variable region。 互補(bǔ)(h249。,第二十六頁(yè)，共五十一頁(yè)。,J鏈,分泌(fēnm236。tā)成分,第二十八頁(yè)，共五十一頁(yè)。 胃蛋白酶水解片段 胃蛋白酶〔pepsin〕水解IgG產(chǎn)生一個(gè)具有雙價(jià)抗體活性的F(ab’)2段和假設(shè)干小分子(fēnzǐ)多肽片段〔pFc’〕。,Synthesis, assembly, and secretion of the immunoglobulin molecule. The heavy and light chains are synthesized on separate polyribosome (polysomes). The assembly of the chains to form the disulfidelinked immunoglobulin molecule occurs as the chains pass through the cisternae of the rough endoplasmic reticulum (RER) into the Golgi apparatus and then into secretory vesicles. The main figure depicts assembly of a secreted antibody. The inset depicts a membranebound antibody, which contains the carboxylterminal transmembrane segment. This form becomes anchored in the membrane of secretory vesicles and then is inserted into the cell membrane when the vesicles fuse with the membrane.,二、免疫(miǎny236。,Expression of membrane forms of ? and ? heavy chains by alternative RNA processing. (a) Structure of rearranged heavychain gene showing C? and C? exons and polyA sites. (b) Structure of ?m transcript and ?m mRNA resulting from polyadenylation at site 2 and splicing. (c) Structure of ?m transcript and ?m mRNA resulting from polyadenylation at site 4 and splicing. Both processing pathways can proceed in any given B cell.,第三十一頁(yè)，共五十一頁(yè)。)上皮細(xì)胞而分泌至粘膜腔，稱 為胞吞轉(zhuǎn)運(yùn)〔transcytosis〕。,第三十二頁(yè)，共五十一頁(yè)。)球蛋白的異質(zhì)性及功能,一、免疫(miǎny236。,免疫(miǎny236。ngyu225。在同一類Ig中，根據(jù)其重鏈抗原性和二硫鍵的數(shù)目和位置的不同，又可分為亞類〔subclass〕。,IgG有IgG1～I(xiàn)gG4四個(gè)亞類；IgA有IgA1和IgA2兩個(gè)(liǎnɡ ɡ232。,第三十五頁(yè)，共五十一頁(yè)。在同一型Ig中，根據(jù)其輕鏈C區(qū)N端氨基酸排列的差異，可分為亞型〔subtype〕。,第三十七頁(yè)，共五十一頁(yè)。ngyu225。ngyu225。 同
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