Disparate suppression of naive effector and memory T cells in tumor-bearing hosts

描述(由申请人提供)：尽管许多团体持续努力开发治疗癌症的免疫方法，但到目前为止，治疗反应令人失望。这一失败的原因尚不清楚。因此，在目前的研究中，我们建议研究T细胞成熟阶段在确定T细胞对肿瘤诱导抑制的敏感性中的作用，这是通过改变转化生长因子-β的敏感性来实现的。记忆性和效应性CD8+T细胞在功能上比幼稚细胞反应更快。因此，我们假设记忆和效应器T细胞比幼稚细胞更不容易受到肿瘤诱导的抑制。矛盾的是，我们发现效应性CD8+T细胞比幼稚细胞(90%比30%)对肿瘤诱导的抑制更敏感。我们的数据提示，过继转移体外激活的CD8+T细胞可能是无效的，因为CD8+T细胞对肿瘤诱导的抑制的敏感性增加。对于这种不同的作用机制，我们发现转化生长因子-b是抑制的关键分子介质，并且转化生长因子-b信号转录调节因子(Smad4和转化生长因子-bRII)的表达与T细胞状态和对抑制的敏感性有关。基于这些观察，我们提出以下假设：CD8+T细胞的成熟状态(幼稚、效应和记忆)决定了对肿瘤诱导的抑制的敏感性，由于对转化生长因子-b的反应性增强，效应者和记忆性T细胞比幼稚T细胞更容易受到抑制。为了评估抗原特异性CD8+T细胞反应，我们将使用来自转基因小鼠的CD8+T细胞，表达抗gp100/PMEL(正常黑素细胞和黑色素瘤细胞自然表达的自身抗原)和非自身抗原鸡卵清蛋白(OT-I)的CD8+TCR。1)我们将在体外检测CD8+T细胞对转化生长因子-β的敏感性，以及转化生长因子-β受体II和Smads的表达是否与抑制敏感性相关。2)评价肿瘤播散性疾病(早期和确诊)对初始、效应和记忆性CD8+T细胞的体内抑制作用，以及去除抑制性细胞或阻断转化生长因子-β对初始、效应和记忆性CD8+T细胞反应的影响。3)我们将研究在体内干扰CD8+T细胞内的转化生长因子-b信号是否均匀地将TCR转基因CD8+T细胞从肿瘤诱导的抑制中拯救出来。 叙述性 到目前为止，基于过继细胞转移和疫苗接种的基于T细胞的抗癌免疫治疗方法的结果令人失望，原因尚不清楚。因此，在目前的研究中，我们建议研究T细胞成熟阶段(初始阶段、效应阶段和记忆阶段)在确定T细胞对通过改变转化生长因子-β敏感性而引起的肿瘤抑制的敏感性方面的作用。

DESCRIPTION (provided by applicant): Despite the sustained efforts of numerous groups to develop immune approaches for the treatment of cancer, thus far, the therapeutic responses have been disappointing. The reasons for this failure remain unknown. Thus, in the current study we propose to study the role of T-cell maturation stage in determining T-cell susceptibility to tumor-induced suppression by alterations in TGF-b susceptibility. Memory and effector CD8+ T cells are functionally more responsive than naive cells. Thus, we hypothesized that memory and effector T cells were less susceptible to tumor-induced suppression than naive cells. Paradoxically, we found that effector CD8+ T cells were considerably more susceptible to tumor-induced suppression than naive cells (90% vs. 30%). Our data suggest that adoptive transfer of in vitro activated effector CD8+ T cells may be ineffective due to increased CD8+ T-cell susceptibility to tumor-induced suppression. Regarding the mechanisms responsible for this disparate effect, we found that TGF-b was a key molecular mediator of suppression, and expression of transcriptional regulators of TGF-b signaling (Smad4 and TGF-bRII) correlated with T-cell status and susceptibility to suppression. Based on these observations, we propose the following hypothesis: CD8+ T-cell maturation status (naive, effector and memory) determines susceptibility to tumor-induced suppression, with effector and memory T cells being more susceptible to suppression than naive T cells, due to increased responsiveness to TGF-b. In order to evaluate antigen specific CD8+ T-cell responses, we will use CD8+ T cells from transgenic mice expressing a CD8+ TCR against gp100/pmel (a self antigen naturally expressed by normal melanocytes and melanoma cells) and a non-self antigen, chicken ovalbumin (OT-I). 1) We will examine the susceptibility of naive, effector and memory CD8+ T cells to TGF-b in vitro, and whether expression of TGF-bRII and Smads correlates with susceptibility to suppression. 2) We will evaluate the in vivo suppressive effect of tumor disseminated disease (early and established) on naive, effector and memory CD8+ T cells, and the effect of depleting suppressor cells or blocking TGF-b on naive, effector and memory CD8+ T-cell responses. 3) We will study whether interfering with TGF-b signaling in vivo in CD8+ T cells evenly rescues naive, effector and memory TCR transgenic CD8+ T cells from tumor-induced suppression. Narrative The results of T-cell based immune therapeutic approaches against cancer based on adoptive cell transfer and vaccination, thus far, have been disappointing for reasons that remain unknown. Thus, in the current study we propose to study the role of T-cell maturation stage (naive, effector and memory) in determining T-cell susceptibility to tumor-induced suppression by alterations in TGF-b susceptibility.