Wojta-Stremayr Daniela, Neunkirchner Alina, Srinivasan Bharani, Trapin Doris, Schmetterer Klaus G, Pickl Winfried F
Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Immunomodulation, Vienna, Austria.
Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
PLoS One. 2015 May 6;10(5):e0126034. doi: 10.1371/journal.pone.0126034. eCollection 2015.
A variety of adjuvants fostering humoral immunity are known as of today. However, there is a lack of adjuvants or adjuvant strategies, which directly target T cellular effector functions and memory. We here determined whether systemically toxic cytokines such as IL-2 can be restricted to the site of antigen presentation and used as 'natural adjuvants'. Therefore, we devised antigen-presenting virus-like nanoparticles (VNP) co-expressing IL-2 attached to different membrane-anchors and assessed their potency to modulate CD8+ T cell responses in vitro and in vivo. Efficient targeting of IL-2 to lipid rafts and ultimately VNP was achieved by fusing IL-2 at its C-terminus to a minimal glycosylphosphatidylinositol (GPI)-anchor acceptor sequence. To identify optimal membrane-anchor dimensions we inserted one (1Ig), two (2Ig) or four (4Ig) immunoglobulin(Ig)-like domains of CD16b between IL-2 and the minimal GPI-anchor acceptor sequence of CD16b (GPI). We found that the 2IgGPI version was superior to all other evaluated IL-2 variants (IL-2v) in terms of its i) degree of targeting to lipid rafts and to the VNP surface, ii) biological activity, iii) co-stimulation of cognate T cells in the absence of bystander activation and iv) potency to induce differentiation and acquisition of CD8+ T cell effector functions in vitro and in vivo. In contrast, the GPI version rather favored memory precursor cell formation. These results exemplify novel beneficial features of membrane-bound IL-2, which in addition to its mere T cell stimulatory capacity include the induction of differential effector and memory functions in CD8+ T lymphocytes.
时至今日，已知多种促进体液免疫的佐剂。然而，目前缺乏直接针对T细胞效应功能和记忆的佐剂或佐剂策略。我们在此确定了诸如白细胞介素-2（IL-2）等具有全身毒性的细胞因子是否可以被限制在抗原呈递部位，并用作“天然佐剂”。因此，我们设计了共表达附着于不同膜锚定物的IL-2的抗原呈递病毒样纳米颗粒（VNP），并评估了它们在体外和体内调节CD8 + T细胞反应的能力。通过将IL-2的C末端与最小糖基磷脂酰肌醇（GPI）锚定受体序列融合，实现了IL-2对脂筏以及最终对VNP的有效靶向。为了确定最佳的膜锚定尺寸，我们在IL-2和CD16b的最小GPI锚定受体序列（GPI）之间插入了CD16b的一个（1Ig）、两个（2Ig）或四个（4Ig）免疫球蛋白（Ig）样结构域。我们发现，就以下方面而言，2IgGPI版本优于所有其他评估的IL-2变体（IL-2v）：i）对脂筏和VNP表面的靶向程度；ii）生物学活性；iii）在无旁观者激活的情况下对同源T细胞的共刺激作用；iv）在体外和体内诱导CD8 + T细胞效应功能分化和获得的能力。相比之下，GPI版本更有利于记忆前体细胞的形成。这些结果例证了膜结合IL-2的新的有益特性，其除了单纯的T细胞刺激能力外，还包括在CD8 + T淋巴细胞中诱导不同的效应和记忆功能。
