标题： 首次通过时间到T细胞激活 显示英文标题

标题： First passage times to T cell activation

摘要： 适应性免疫系统对异源抗原的有效识别依赖于T细胞在淋巴结中被抗原呈递细胞（APCs）激活。 在这里，扩散的T细胞可能会遇到呈现匹配抗原片段的同源APCs或不呈现的非同源APCs；它们也会受到降解的影响。 我们开发了一个随机模型，其中T细胞与APCs通过一系列识别步骤相互作用，表示为多阶段马尔可夫链。 只有当达到与同源APC相关的终态时，T细胞才能被成功激活。 我们在存在干扰的非同源APCs、T细胞降解和淋巴结退出的情况下计算成功激活的概率，并分析到达激活的平均首次通过时间。 我们还引入了一个动能验证机制，该机制能够实现状态重置，并展示了这种机制如何提高对同源APCs的特异性。 显示英文摘要

摘要： Effective recognition of foreign antigens by the adaptive immune system relies on T cells being activated by antigen-presenting cells (APCs) in lymph nodes. Here, diffusing T cells may encounter cognate APCs that present matching antigen fragments or non-cognate ones that do not; they are also subject to degradation. We develop a stochastic model in which T cell-APCs interact via a sequence of recognition steps, represented as a multistage Markov chain. T cells are successfully activated only if the terminal state associated with a cognate APC is reached. We compute the probability of successful activation in the presence of interfering non-cognate APCs, T cell degradation, and lymph node exit, and analyze the mean first-passage time to activation. We also incorporate a kinetic proofreading mechanism that enables state resetting, and show how this enhances specificity toward cognate APCs.