EASL 2018 SAT-429 TLR8激动剂对MAIT细胞的细胞因子依赖性激活 GS-96

StephenW

EASL 2018 SAT-429
Cytokine-dependent activation of MAIT cells by the TLR8 agonist
GS-9688 but not the TLR7 agonist GS-9620
S. Daffis, M. Morar, D. Pattabiraman, C. Voitenleitner, S. Fletcher,
H. Javanbakht. Gilead Sciences, Biology, Foster City, United States
Email: [email protected]
Background and Aims: GS-9688 is a selective small molecule agonist
of toll-like receptor 8 (TLR8) in clinical development for the
treatment of chronic hepatitis B (CHB). GS-9620 is an oral small
molecule TLR7 agonist which has recently completed phase 2 studies
in CHB patients. Oral GS-9688 and GS-9620 induce an immune
response by pre-systemic activation of gut-associated and intrahepatic
immune cells. Mucosal associated invariant T (MAIT) cells are
innate-like Tcells enriched in the gut and liver that likely play a role in
host antiviral defense. Here we characterized in vitro activation of
MAIT cells in human peripheral blood mononuclear cells (PBMCs)
fromhealthy donors (HD) and CHB patients by GS-9688 and GS-9620.
Method: PBMCs obtained from HDs and age-matched CHB patients
(n = 8) were treated for 18 hours with GS-9688 (156nM) or GS-9620
(10nM) and cytokineswere analyzed by Luminex® assay. Intracellular
levels of IFN-γ and TNF-α (antiviral cytokines), and granzyme B (a
marker of cytotoxic function) in MAIT cells (CD3+TCRγδ−CD161+
Vα7.2+) were evaluated by flow cytometry.
Results: Consistent with previous studies, GS-9688 strongly induced
IL-12p70 and IL-18, but had minimal effect on IFN-α (a TLR7-induced
cytokine) in HD PBMCs. GS-9688 also strongly induced intracellular
IFN-γ (38-fold increase), granzyme B (17-fold increase) and TNF-α
(4-fold increase) levels in MAIT cells. Cytokine neutralization studies
demonstrated that GS-9688 indirectly activates MAIT cells, predominantly
via production of IL-12p70 and IL-18. The frequency of MAIT
cells and activation by GS-9688 were comparable in PBMCs from HDs
and CHB patients. GS-9620 induced dose-dependent IFN-α, but little
to no IL-12p70 and IL-18 in PBMCs. Consistent with this cytokine
profile, GS-9620 onlyweakly induced intracellular IFN-γ, granzyme B
and TNF-α levels in MAIT cells.
Conclusion: In line with previous studies with prototypic TLR
agonists, GS-9688 –but not GS-9620– strongly induced cytolytic
and non-cytolytic functions of human MAIT cells in vitro. These data
confirm that these innate-like T cells are indirectly activated by TLR8
but not TLR7 agonists, suggesting there are important immunological
differences in the intrahepatic response induced by GS-9688 and
GS-9620.

StephenW

EASL 2018 SAT-429
TLR8激动剂对MAIT细胞的细胞因子依赖性激活
GS-9688但不是TLR7激动剂GS-9620
S. Daffis，M. Morar，D. Pattabiraman，C. Voitenleitner，S. Fletcher，
H. Javanbakht。吉列德科学，生物学，福斯特城，美国
电子邮件：[email protected]
背景和目标：GS-9688是一种选择性小分子激动剂
Toll样受体8（TLR8）在临床发展中的作用
治疗慢性乙型肝炎（CHB）。 GS-9620是一款小型口服
分子TLR7激动剂，最近完成了2期研究
在CHB患者中。口服GS-9688和GS-9620诱导免疫
通过肠系统前和肝内系统前激活的反应
免疫细胞。粘膜相关不变T（MAIT）细胞
先天性T细胞在肠道和肝脏中富集，可能在其中起作用
主持抗病毒防御。在这里我们表征了体外激活
人外周血单个核细胞（PBMCs）中的MAIT细胞
来自健康捐献者（HD）和CHB患者通过GS-9688和GS-9620。
方法：从HDs和年龄匹配的CHB患者获得的PBMCs
（n = 8）用GS-9688（156nM）或GS-9620处理18小时
（10nM）和细胞因子用Luminex测定分析。细胞内
IFN-γ和TNF-α（抗病毒细胞因子）水平和颗粒酶B（a
细胞毒性功能标志物）在MAIT细胞（CD3 +TCRγδ-CD161 +）中的表达
Vα7.2+）通过流式细胞术进行评估。
结果：与先前的研究一致，GS-9688强烈诱导
IL-12p70和IL-18，但对IFN-α（TLR7诱导的
细胞因子）在HD PBMC中。 GS-9688也强烈诱导细胞内
IFN-γ（增加38倍），粒酶B（增加17倍）和TNF-α
（4倍增加）水平的MAIT细胞。细胞因子中和研究
证明GS-9688主要间接激活MAIT细胞
通过产生IL-12p70和IL-18。 MAIT的频率
细胞和GS-9688的激活在来自HD的PBMC中是可比较的
和CHB患者。 GS-9620诱导剂量依赖性IFN-α，但很少
至PBMC中无IL-12p70和IL-18。与这种细胞因子一致
简介，GS-9620仅弱诱导细胞内IFN-γ，粒酶B
和MAIT细胞中的TNF-α水平。
结论：与以前的原型TLR研究一致
激动剂，GS-9688（但不是GS-9620）强烈诱导细胞溶解
和体外人MAIT细胞的非溶细胞功能。这些数据
证实这些先天性T细胞被TLR8间接激活
但不是TLR7激动剂，暗示有重要的免疫学
GS-9688和TNF-α诱导的肝内反应的差异
GS-9620。