histocompatibilitycomplex(主要組織相容性復(fù)合體)-在線瀏覽
2025-03-22 07:50本頁面
【正文】 iii. T cell development in thymus B. HLAⅡ molecules 1. Structure – Heterodimers of α andβglycoprotein chains. – Each chain has 2domains(α1, α2 and β1, β2) – α1 and β1 form the binding groove. (the polymorphic region) – CD4 bind to β2 domain 2. Cellular distribution – class Ⅱ molecules are expressed on ? B cells ? Mφ ? Dendritic cells ? Vascular endothelial cells 3. Functions i. Antigen processing and presenting (exogeneous pathway): – both pathogens in cellular vesicles and those e from outside the cell are presented on MHC class Ⅱ molecules of APCs and are transported to the cell surface where they can be recognized by CD4 + T cell ii. Involve in transplant rejection iii. Regulation of immune response iv. T cell development in the thymus C. Nonclassical HLA – (HLAⅠ b) 1. Differentiation or activation states 2. Disease 3. Cytokines IV. Factors influencing the expression of HLA molecules （ 1）內(nèi)源性抗原提呈：抗原 ? 靶細(xì)胞 ? 組成 HLAⅠ 類分子 抗原肽復(fù)合物 ? 表達(dá)于細(xì)胞膜表面 ? CD8+T細(xì)胞識別。 （ 2）外源性抗原提呈： 抗原 ? APC ?HLAⅡ 類分子 抗原肽復(fù)合物 ? 表達(dá)于細(xì)胞膜表面 ? CD4+T細(xì)胞識別 。 （二）舉例 B27 （ IDDM）與 DR DR4
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