前T细胞表面分子是MHC_Ⅱ类和MHC_Ⅰ类分子的受体,其未能与胸腺上皮细胞表面MHC_Ⅱ类和MHC_Ⅰ类分子发生有效结合的CD4+、CD8+双阳性细胞,则发生程序性细胞死亡,即为阳性选择过程。
阳性选择 ( positive selection ):适应性进化,达尔文进化,DNA分子显著出现非同义替代,改变编码蛋白质的氨基酸组成,并产生新的功能; 2.
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T细胞阳性选择 T cell positive selection
阳离子选择性透过膜 cation permselective membrane
阳离子选择性 cation slectivity
太阳能选择性吸收涂层 Solar Selective Absorbing Coatings
IntroductionPluripotent lymphocytle stem cells transfer to thymic,gradually from the cortex into the the medulla in thymus. After negative selection and positive selection,T cells have become Progressive differentiation and maturation.
前言多能淋巴干细胞迁移至胸腺,从胸腺的皮质逐渐移行到髓质,经过阳性选择和阴性选择,逐步分化成熟为T细胞。
参考来源 - 胸腺γδT细胞的分化去向In addition, this paper proposes a detector maturation algorithm based on T-cell immunity and tolerance by means of simulating maturation mechanism of T cell including positive selection and negative selection.
此外,本文通过模拟T细胞的培育机制,包括阴性选择和阳性选择,提出了基于T细胞免疫耐受的检测器生成算法。
参考来源 - 基于免疫的网络入侵检测模型及算法的研究·2,447,543篇论文数据,部分数据来源于NoteExpress
阳性选择决定了成熟T细胞的MHC限制性,阴性选择使机体获得自身免疫耐受。
The MHC restriction of t cell is determined in positive selection. The tolerance of t cells to autoantigen is acquired during negative selection.
准种的演变不仅是机体阳性选择压力的结果,也有阴性选择的参与,即随机突变积累的结果。
The evolvement of quasispecies is not only the result of positive immune pressure in the host, but also the accumulation of random mutation.
在其他语言中,当复数总是阳性或阴性时,就没有这种选择了。
That option is unavailable when the plural is always masculine or feminine in other languages.
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