DM ENHANCES PEPTIDE BINDING TO CLASS-II MHC BY RELEASE OF INVARIANT CHAIN-DERIVED PEPTIDE
DM ENHANCES PEPTIDE BINDING TO CLASS-II MHC BY RELEASE OF INVARIANT CHAIN-DERIVED PEPTIDE
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DOI：
10.1016/1074-7613(95)90089-6
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发表时间：
1995-08-01
期刊：
影响因子：
32.4
通讯作者：
JENSEN, PE
中科院分区：
文献类型：
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作者：
SHERMAN, MA;WEBER, DA;JENSEN, PE
主要组织相容性复合体（MHC）II类分子在抗原呈递细胞（APC）中生物合成后迅速结合抗原肽。相比之下，肽与纯化的II类分子结合的速率非常慢。我们发现，纯化的HLA-DR分子结合肽迅速存在，但不是没有HLA-DM，最近确定的异源二聚体所需的有效的抗原加工。与免疫沉淀DM看到相同的效果，这表明DM直接与DR相互作用。II类相关的不变链肽（CLIP）的选择性和快速释放DR与DM在pH 5孵育期间。我们的结论是，DM是一种辅助因子，通过涉及肽交换的机制，增强肽与DR分子的结合。
Major histocompatibility complex (MHC) class II molecules bind antigenic peptides rapidly after biosynthesis in antigen-presenting cells (APCs). By contrast, the rate of peptide binding to purified class II molecules is remarkably slow. We find that purified HLA-DR molecules bind peptides rapidly in the presence but not the absence of HLA-DM, a recently identified heterodimer required for efficient antigen processing. The same effect is seen with immunoprecipitated DM, suggesting that DM interacts directly with DR. Class II-associated invariant chain peptides (CLIP) are selectively and rapidly released from DR during incubation with DM at pH 5. We conclude that DM is a cofactor that enhances peptide binding to DR molecules through a mechanism involving peptide exchange.