H3N2流感病毒HA保守Th表位对CD4^(+)T细胞活化及分化的影响

The conserved Th epitopes on the HA of H3N2 virus induced activation and differentiation of CD4^(+)T cells

目的探讨H3N2病毒HA保守Th表位对CD4^(+)T细胞活化及分化的影响,为后续研究通用流感疫苗奠定基础。方法利用NetMHCⅡpan-4.0软件预测H3N2疫苗株A/Kansas/14/2017 HA的Th表位,以IC 50<500 nM为标准筛选阳性预测表位;采用SWISS-MODLE对A/Kansas/14/2017 HA进行同源建模,在3D模型上定位保守Th表位,根据表位的亲和力、保守性及核心序列的位置筛选高保守表位;合成6个非重叠的高保守Th表位,用保守Th表位体外刺激健康人外周血单核细胞,流式细胞术分析CD4^(+)T细胞表面分子CD69及细胞因子IFN-γ、IL-4的表达。结果在A/Kansas/14/2017 HA中共筛选到48个阳性预测Th表位,其中33个在H3-HA中是保守的;成功构建A/Kansas/14/2017 HA 3D模型,27个保守Th表位位于HA头部,其余6个位于杆部;人外周血PBMC经保守Th表位刺激后,CD69分子表达增加,细胞因子IFN-γ和IL-4合成增加。结论筛选到的6个H3N2 HA高保守Th表位具有免疫原性,可刺激CD4^(+)T细胞活化及分化。

Objective To investigate the effect of the conserved Th epitopes on the HA of H3N2 on activation and differentiation of CD4^(+)T cells.Methods The Th epitopes on the HA of H3N2 influenza virus strain A/Kansas/14/2017 were predicted by NetMHCIIpan-4.0 and the epitopes were selected as positive if IC 50<500 nM.The conserved epitopes were decided by the homology of amino acids among H3N2 strains,and further confirmed using SWISS-MODLE.Six epitopes were synthetized and used to stimulate peripheral blood mononuclear cells(PBMC).CD69,IFN-γand IL-4 were analyzed by flow cytometry.Results The 48 Th epitopes were predicted on the HA of A/Kansas/14/2017.Of 48,33 epitopes were found to be conserved among H3N2 strains.For six highly conserved Th epitopes,four is on the HA head,two on the stalk.The expression of CD69,IFN-γand IL-4 was increased after stimulation with the conserved Th epitopes.Conclusion The highly conserved Th epitopes can induce the activation and differentiation of CD4^(+)T cells,indicating a potential strategy for the universal influenza vaccine.