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

描述（由申请人提供）：尽管许多小组持续努力开发用于治疗癌症的免疫方法，但迄今为止，治疗反应令人失望。失败的原因仍然不明。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细胞对肿瘤诱导的抑制的敏感性中的作用，通过改变TGF-β的敏感性。记忆和效应CD 8 + T细胞在功能上比幼稚细胞更具响应性。因此，我们假设记忆和效应T细胞比幼稚细胞对肿瘤诱导的抑制更不敏感。巧合的是，我们发现效应CD 8 + T细胞比初始细胞对肿瘤诱导的抑制更敏感（90%对30%）。我们的数据表明，过继转移的体外活化效应CD 8 + T细胞可能是无效的，由于增加的CD 8 + T细胞的易感性肿瘤诱导的抑制。关于这种不同效应的机制，我们发现TGF-β是抑制的关键分子介质，TGF-β信号传导的转录调节因子（Smad 4和TGF-β RII）的表达与T细胞状态和对抑制的敏感性相关。基于这些观察结果，我们提出了以下假设：CD 8 + T细胞成熟状态（幼稚、效应和记忆）决定了对肿瘤诱导的抑制的易感性，效应和记忆T细胞比幼稚T细胞更容易受到抑制，这是由于对TGF-β的反应性增加。为了评估抗原特异性CD 8 + T细胞应答，我们将使用来自表达针对gp 100/pmel（正常黑素细胞和黑素瘤细胞天然表达的自身抗原）和非自身抗原鸡卵清蛋白（OT-I）的CD 8 + TCR的转基因小鼠的CD 8 + T细胞。1)我们将研究幼稚、效应和记忆CD 8 + T细胞对体外TGF-β的易感性，以及TGF-β RII和Smads的表达是否与对抑制的易感性相关。2)我们将评估肿瘤播散性疾病（早期和建立）对初始、效应和记忆CD 8 + T细胞的体内抑制作用，以及耗尽抑制细胞或阻断TGF-β对初始、效应和记忆CD 8 + T细胞应答的影响。3)我们将研究在体内干扰CD 8 + T细胞中的TGF-b信号传导是否均匀地从肿瘤诱导的抑制中拯救幼稚、效应和记忆TCR转基因CD 8 + T细胞。 叙事 迄今为止，基于过继细胞转移和疫苗接种的基于T细胞的针对癌症的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（幼稚，效应和记忆）在确定T细胞的敏感性肿瘤诱导的抑制TGF-β敏感性的改变的作用。

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.