a Qantu Therapeutics, Inc , Lewisville , TX , USA.
Autoimmunity. 2017 Nov;50(7):393-402. doi: 10.1080/08916934.2017.1373766. Epub 2017 Sep 14.
A promising treatment for T-cell-mediated autoimmune diseases is the induction of immune tolerance by modulating the immune response against self-antigens, an objective that may be achieved by vaccination. There are two main types of vaccines currently under development. The tolerogenic vaccines, composed of proteins formed by a cytokine fused to a self-antigen, which usually induce tolerance by eliminating the T-cells that are immune reactive against the self-antigen. The immunogenic vaccines, comprised of a self-antigen plus a sole Th2 adjuvant either free or conjugated, that alleviate autoimmunity by switching the immune response against the self-antigen, from a damaging pro-inflammatory Th1/Th17 to an anti-inflammatory Th2 immunity. Another type of vaccines is the DNA vaccines, where cells transiently express the self-antigen encoded by DNA, which induces a Th2 immunity. Actually, DNA vaccines can benefit from the presence of an adjuvant that elicits a systemic sole Th2 immunity to enhance the initially weak immune response characteristic of these vaccines. While in the tolerogenic vaccines, cytokines are the endogenous immunomodulators, in the immunogenic vaccines, the adjuvants are exogenous agents that elicit Th2 immunity with a production of anti-inflammatory cytokines and antibodies against the self-antigen. Because the commonly used Th2 adjuvant alum, fails to induce an effective immunity in the elderly population, it is unlikely that it would be widely used. Another Th2 adjuvant, the oil/water emulsions mixed with the antigen, while effective in vaccines against infectious agents, due to potential aldehydes in their formulation may be not suitable for autoimmune vaccines. A unique compound is glatiramer, which seems to be both a random polypeptide antigen and an immune modulator that biases the response to Th2 immunity. Its mechanism of action seems to implicate binding to MHC-II, which alters the outcome of T-cell signaling, leading to anergy. Glatiramer, while effective in the treatment of multiple sclerosis has not shown efficacy in other autoimmune diseases. An important new group of promising sole Th2 adjuvants are the fucosylated glycans, which by binding to DC-SIGN bias dendritic cells to Th2 immunity while inhibiting Th1/Th7 immunities. These glycans are similar to those produced by parasitic helminths to prevent inflammatory responses by mammalian hosts. A novel group of sole Th2 adjuvants are some plant-derived fucosylated triterpene glycosides, which share the immune modulatory properties from the fucosylated glycans. These glycosides have also an aldehyde group that delivers an alternative co-stimulatory signal to T-cells, averting the anergy associated with aging due to the loss of the CD28 receptor on T-cells. Hence, the development of vaccines to treat and/or prevent autoimmune conditions and some proteopathies, will significantly benefit from the availability of new sole Th2 adjuvants that while inducing an anti-inflammatory immunity, they do not abrogate pro-inflammatory Th1/Th17 immunities.
一种有前途的治疗 T 细胞介导的自身免疫性疾病的方法是通过调节针对自身抗原的免疫反应来诱导免疫耐受,这一目标可以通过疫苗接种来实现。目前正在开发两种主要类型的疫苗。耐受性疫苗由与自身抗原融合的细胞因子组成的蛋白质组成,通常通过消除对自身抗原免疫反应的 T 细胞来诱导耐受性。免疫原性疫苗由自身抗原加上单一 Th2 佐剂组成,无论是游离的还是结合的,通过将针对自身抗原的免疫反应从致炎的 Th1/Th17 切换为抗炎的 Th2 免疫来缓解自身免疫。另一种类型的疫苗是 DNA 疫苗,其中细胞瞬时表达由 DNA 编码的自身抗原,从而诱导 Th2 免疫。实际上,DNA 疫苗可以受益于存在佐剂,该佐剂可以引发全身性单一 Th2 免疫,以增强这些疫苗最初较弱的免疫反应。在耐受性疫苗中,细胞因子是内源性免疫调节剂,而在免疫原性疫苗中,佐剂是外源性物质,可通过产生抗炎细胞因子和针对自身抗原的抗体来引发 Th2 免疫。由于常用的 Th2 佐剂明矾不能在老年人群中诱导有效的免疫,因此不太可能广泛使用。另一种 Th2 佐剂,油/水乳液与抗原混合,虽然在针对传染病的疫苗中有效,但由于其配方中可能存在醛,因此可能不适合自身免疫疫苗。一种独特的化合物是聚甘氨酸,它似乎既是一种随机多肽抗原,也是一种免疫调节剂,可偏向于 Th2 免疫。其作用机制似乎涉及与 MHC-II 的结合,该结合改变了 T 细胞信号转导的结果,导致失能。聚甘氨酸虽然在多发性硬化症的治疗中有效,但在其他自身免疫性疾病中并未显示出疗效。一组有前途的新型单一 Th2 佐剂是糖基化糖,它通过与 DC-SIGN 结合使树突细胞偏向 Th2 免疫,同时抑制 Th1/Th7 免疫。这些糖与寄生虫蠕虫产生的糖相似,可防止哺乳动物宿主发生炎症反应。一组新型的单一 Th2 佐剂是一些植物来源的糖基化三萜糖苷,它们具有与糖基化糖相同的免疫调节特性。这些糖苷还具有醛基,可向 T 细胞提供另一种共刺激信号,避免由于 T 细胞上 CD28 受体的丧失而导致与衰老相关的失能。因此,开发用于治疗和/或预防自身免疫性疾病和一些蛋白质疾病的疫苗将从新型单一 Th2 佐剂的可用性中受益匪浅,这些佐剂在诱导抗炎免疫的同时,不会消除致炎的 Th1/Th17 免疫。
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