WAS蛋白缺陷对T细胞记忆形成的影响

The Wiskott-Aldrich syndrome（WAS）is an X-linked primary immunodeficiency disease and caused by WAS gene mutation.WAS protein(WASp),coded by WAS gene,is a key regulator of actin polymerization in hematopoietic cells,playing an important role in the development,motility and activation of almost all kinds of immune cells.The mechanism of immunodeficiency in patients with WAS remains unknown.For the first time,we found that the TCR diversity was selectively skewed in memory T cell subpopulations such as CD4 positive memory T cells in children with WAS as compared with healthy controls,indicating impaired T cell memory in this disease.This finding, together with the well-known principle seen in WAS clinical course,that infection is more frequent and more severe when WAS patients grow up, lead to our central hypothesis：WASp deficiency may mainly interfere establishment of T cell memory and the ineffecient T cell memory establishment and impaired secondary T cell response, which obviously governs the whole cellular secondary response, might result in the recurrent infections in patients with WAS.To test this hypothysis,we will conduct deep sequecing to see if the TCR diversity is specifically reduced in memory T cells, then use a number of classic and latest immunological assays in WAS patients sample and was-/- mice to validate that the memory establishment is impaired due to defective WASp.The present study will be a novel try to reveal the fundamental abnormality in WAS and thus may provide a new explanation for the immunodeficiency in WAS and inspire some new treatment strategy.

湿疹血小板减少伴免疫缺陷综合征（WAS）是一种X连锁原发性免疫缺陷病，由WAS基因突变引起其编码的WAS蛋白（WASp）缺陷所致。WASp为重要的肌动蛋白调节分子，参与众多免疫细胞的发育、移动、活化等过程，但WAS免疫缺陷的确切机制仍未阐明。结合WAS病人随年龄增长逐渐出现严重机会病原体感染的特点，及本课题组前期发现WAS患儿CD4阳性记忆T细胞TCR多样性明显受限，我们提出科学假设：WASp缺陷导致T细胞记忆形成障碍，可能是WAS患儿免疫缺陷的核心和反复感染的根本原因。本研究拟从人和was基因敲除鼠两个层次，首先分析WAS病人外周血各T细胞亚群的抗原受体多样性，进一步采用经典和新近的记忆T细胞研究方法观察WASp缺陷状态下记忆T细胞数量、功能和免疫保护效能变化，充分证实上述科学假设。本研究为原创性研究，研究结果可能为揭示WASp参与免疫记忆形成机制和发展基于此的治疗策略提供崭新线索。

WAS综合征是一种X连锁原发性免疫缺陷病，通常男性患病，幼年出现湿疹、血小板减少，继而以反复感染、 自身免疫和易患肿瘤为特征。现有研究结果已经证实 T 细胞功能缺陷是其免疫缺陷的核心原因。但WAS患儿在生命早期(尤其是婴幼儿期)感染的频次与严重程度似乎与正常同龄儿童并无差异，随着年龄的增长，WAS 患儿逐渐表现为明显异于正常儿童的缺陷免疫应答，感染成为该病最重要的死因。本研究运用一代测序及高通量测序，进行了WAS患儿记忆T细胞各亚群TCR多样性的评估。应用病毒感染WAS基因敲除小鼠及同窝WT小鼠，进行了CD8+T细胞记忆相关的研究。结果发现，WAS患儿记忆CD4及耗竭性CD8的TCR多样性明显受限。WAS小鼠的抗原特异性记忆CD8+T细胞明显减少，再次应答能力降低，保护性反应减弱，同时发现WAS小鼠的耗竭T增多，经抗原肽刺激产生的细胞因子增多。这解释了大龄WAS患儿感染频率较同龄儿童明显升高。这有助于加深我们对抗原特异性CD8+T细胞稳态维持的理解。有利于今后研发新的、有效的 WAS 治疗策略和疫苗策略。