抗原的加工與呈遞ppt課件(已改無錯字)
2023-06-04 23:11:36 本頁面
【正文】 ith antigen containing vesicles Removal of CLIP ? How can the peptide stably bind to a floppy binding site? Competition between large number of peptides HLADM catalyses the removal of CLIP MIIC partment HLADM Replaces CLIP with a peptide antigen using a catalytic mechanism Sequence in cytoplasmic tail retains HLADM in endosomes HLADM HLADR Conception ? MⅡ C – MHC class Ⅱ partment， MHCⅡ 類分子區(qū)室 – 富含外源性抗原肽、 MHCⅡ 類分子、 HLADM的低 pH值的晚期內體 – MHCⅡ 類分子荷肽主要場所 ? HLADM的編選作用 – HLADM可驅逐與 Ⅱ 類分子抗原結合槽低親和 力結合的肽，直至有高親和力的肽與Ⅱ 類分 子結合，才與 Ⅱ 類分子分離，使其抗原結合 槽恢復閉合狀態(tài)。 – HLA這種對肽的選擇作用稱為 HLADM的編選 作用，保證 Ⅱ 類分子遞呈高親和力的外源 性抗原肽。 遞呈給 CD4+T細胞 ? Presentation of exogenous antigen – Ag肽 Ⅱ 類分子經胞吐作用表達于 APC表面 – 供 CD4+T細胞識別 MIIC partment sorts peptideMHC plexes for surface expression or lysosomal degradation Surface expression of MHC class II peptide plexes Exported to the cell surface Sent to lysosomes for degradation 二、內源性抗原加工遞呈途徑 ? Endogenous processing and presentation pathway ? MHC class Ⅰ pathway 內源性 Ag加工后由 MHCⅠ 類分子遞呈 階段： ? 內源性 Ag肽的產生及轉運 ? MHCⅠ 類分子荷肽 ? 遞呈給 CD8+T細胞 MHCⅠ 類途徑 內源性抗原肽的產生 ? Generation of endogenous antigenic peptide – 內源性抗原泛素化 – 經蛋白酶體（ LMP）降解為短肽 Crystal Structure Of The 20s Proteasome From Yeast View End on Degradation in the proteasome These ponents are induced by IFNγ and replace constitutive ponents to confer proteolytic properties The ponents of the proteasome include MECL1, LMP2, LMP7 LMP2 amp。 7 encoded in the MHC Proteasome cleaves proteins into hydrophobic and basic amino acids Cytoplasmic cellular proteins, including nonself proteins are degraded continuously by a multicatalytic protease of 28 subunits 內源性抗原肽轉運至內質網 ? Transportation of endogenous antigenic peptide into ER – 經抗原加工相關轉運體（ TAP）轉運至 ER ER CYTOSOL Peptide antigens produced in the cytoplasm are physically separated from newly formed MHC class I Newly synthesised MHC cla
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