抗原的加工與呈遞ppt課件-資料下載頁
2025-05-04 23:11本頁面
【正文】 ss I molecules Peptides need access to the ER in order to be loaded onto MHC class I molecules ER membrane Lumen of ER Cytosol Transporters associated with antigen processing (TAP1 amp。 2) Transporter has preference for 815 amino acid peptides with hydrophobic, basic C termini Peptide Peptide Peptide ATPbinding cassette (ABC) domain Hydrophobic transmembrane domain Peptide antigens from proteasome MHCⅠ 類分子荷肽 ? Peptideloading of MHC class Ⅰ molecules – 內(nèi)質網(wǎng)內(nèi)鈣聯(lián)蛋白、鈣網(wǎng)蛋白協(xié)助下 MHCⅠ 類分子合成 – tapasin協(xié)助下 MHCⅠ 類分子與 TAP孔道內(nèi)側口結合 – Ag肽 MHCⅠ 類分子復合物形成 Endoplasmic reticulum Calnexin binds to nascent class I chain until β2M binds Peptide Peptide Peptide β2M binds and stabilises floppy MHC Tapasin, calreticulin, TAP 1 amp。 2 form a plex with the floppy MHC Cytoplasmic peptides are loaded onto the MHC molecule and the structure bees pact Maturation and loading of MHC class I 遞呈給 CD8+T細胞 ? Presentation of endogenous antigen – Ag肽 MHCⅠ 類分子經(jīng)高爾基體 – 通過胞吐作用表達于細胞表面 – 供 CD8＋ T細胞識別 Fate of MHC class I Sent to lysosomes for degradation Exported to the cell surface Endoplasmic reticulum Peptide Peptide HSV protein blocks transport of viral peptides into ER Sent to lysosomes for degradation Evasion of immunity by interference with endogenous antigen processing Sent to lysosomes for degradation Normally exported to the cell surface Adenoviral protein retains MHC class I in the ER Evasion of immunity by interference with endogenous antigen processing 三、非經(jīng)典抗原加工遞呈途徑 ? Non classical pathway ? 外源性抗原也可被 MHCⅠ 類分子遞呈 – 外源性抗原穿透細胞膜進入胞漿 – 外源性抗原自內(nèi)體逸出進入胞漿 以內(nèi)源性抗原方式加工遞呈給 CD8+T細胞 ? 內(nèi)源性抗原也可被 MHCⅡ 類分子遞呈 – 胞質內(nèi)蛋白形成自吞小泡，與內(nèi)體 /溶酶體融合 以外源性抗原方式加工遞呈給 CD4+T細胞 ? 交叉致敏（ crosspriming） – 專職性 APC 激活未致敏的腫瘤或病毒抗原特異性 CD8+T細胞的機制 – DC具有交叉致敏作用 學習了抗原提呈細胞的特性和功能后， 你是如何體會抗原提呈細胞的免疫學功能和生物學意義的呢？
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