QMS Technology to Deplete T Cell Alloreactivity

描述（由申请人提供）：同种异体造血干细胞移植仍然是许多血液系统恶性肿瘤患者唯一的治疗选择。移植物抗宿主病（GvHD）是跨越组织相容性障碍的造血细胞移植的主要限制，并且有效地限制了从治疗中受益的少数患者的移植。大量的T细胞消耗供体移植物可以消除GvHD。然而，T细胞耗竭的一个重要后果是移植后T细胞免疫缺陷状态的深刻和持久，导致严重的机会性病毒和真菌感染，严重限制了生存。移植后过继输注成熟的记忆性T细胞可能提供抵抗机会性感染的保护，并缩短免疫缺陷期，直到成功的免疫重建发生。然而，这种策略在降低T细胞耗尽移植后死亡率方面的成功，将取决于选择性去除介导GvHD的同种异体反应性T细胞，同时保留大量能够对病毒和第三方抗原起反应的记忆T细胞。尽管已经研究了许多方法，但消耗同种异体反应性T细胞的程度仅限于<3 log，这并不能完全阻止GvHD，并且限制了可以注入以提高免疫力的T细胞的数量。具有同种异体反应电位的供体T细胞的不完全体外激活和/或激活细胞的低效消耗都可能导致同种异体反应活性的次优消耗。本提案的总体目标是开发一种用于临床使用的有效消耗同种异体反应性T细胞的系统。具体而言，我们的目标是：1)通过研究培养条件和不同抗原在活化T细胞上选择性表达的动力学，优化激活供体特异性T细胞的最大数量的条件，作为消耗靶点；2)开发GMP级高性能免疫磁分离系统，四极磁细胞分选（QMS），用于临床规模的激活供体T细胞耗竭，能够使同种异体反应性T细胞耗竭>=3 log，同时保留80%的第三方反应性。本提案中开发的技术将极大地促进过继供体T细胞治疗的临床试验的发展，以改善T细胞耗尽错配干细胞移植后的免疫功能。

DESCRIPTION (provided by applicant): Allogeneic hematopoietic stem ceil transplantation remains the only curative option for many patients with hematological malignancies. Graft-versus-host disease (GvHD) is a major limitation to transplantation of hematopoeitic cells across histocompatibility barriers, and effectively limits transplantation to a minority of patients who would benefit from treatment. Extensive T cell depletion of the donor graft can eliminate GvHD. A significant consequence of T cell depletion, however, is a profound and long-lasting T cell immunodeficiency state post-transplant resulting in severe opportunistic viral and fungal infections that significantly limit survival. The adoptive infusion of mature, memory T cells post-transplant may offer protection against opportunistic infection, and shorted the period of immunodeficiency until successful immune reconstitution occurs. The success of this strategy in reducing mortality following T cell depleted transplants, however, will depend on the selective removal of alloreactive T cells that mediate GvHD, while retaining a high repertoire of memory T cells capable of reacting to viral and third party antigens. Although a number of methods have been investigated, the extent of depleting alloreactive T cell has been limited only to <3 log, which has not fully prevented GvHD and limited the number of T cells that can be infused to improve immunity. Either incomplete in-vitro activation of donor T cells with alloreactive potential and/or inefficient depletion of the activated cells likely contributes to suboptimal depletion of alloreactivity. The overall goal of this proposal is to develop a system for efficient depletion of alloreactive T cells for clinical use. Specifically, we aim to 1) Optimize the conditions for activating the maximum number of donor-specific T cells by studying culture conditions and the kinetics of different antigens expressed selectively on activated T cells for use as targets in depletion, and 2) Develop a GMP grade hiqh-performance immunomagnetic separation system, quadrupole magnetic cells sorting (QMS), for clinical scale depletion of activated donor T cells that is capable of >=3 log depletion of alloreactive T cells while retaininq >80% of third party reactivity. The technology developed in this proposal should greatly facilitate the development of clinical trials of adoptive donor T cell therapy to improve immune function following T-cell-depleted mismatched stem cell transplants.