SARS康复者特异性细胞免疫和免疫记忆T细胞功能的研究

Specific response to SARS-CoV S peptides of peripheral memory T cell from individuals fully recovered from SARS

目的 观察完全康复期严重急性呼吸综合征 (SARS)患者外周血针对SARS冠状病毒(SARS CoV)S抗原多肽的特异性细胞免疫反应。方法 分离外周血单个核细胞 (PBMC) ,经混合S抗原多肽刺激后 ,采用酶联免疫吸附试验 (ELISA)和酶联免疫斑点试验 (ELISPOT)检测 ,分析完全康复期SARS患者抗原特异性T淋巴细胞应答反应。结果 当SARS CoV的S抗原混合多肽刺激后 ,只有SARS康复期患者的PBMC分泌大量的IFN γ。同时 ,IFN γ产生细胞的阳性率也显著高于健康对照组 (P <0 .0 5)。此外 ,当用多克隆刺激剂 (PMA +ionomycin)刺激后 ,正常人和康复期SARS患者的PBMC产生等量的IFN γ及IFN γ产生细胞 ,两者经统计学处理 ,差异无统计学意义 (P >0 .0 5)。结论SRAS CoV不仅能诱导中和抗体的产生 ,而且还可诱导抗原特异性细胞免疫应答反应 ,并可在体内长期维持免疫记忆功能。

Objective To elucidate the long lasting memory T cell immune response specific for SARS S antigen by PBMCs from individuals fully recovered from SARS. Methods PBMCs were cultured in the presence or absence of pooled SARS S peptides. The level of IFN γ in the supernatant was examined by ELISA and the frequency of IFN γ producing cells was analyzed at the single cell level by ELISPOT following stimulation with SARS CoV S peptides. Results High level of IFN γ in supernatant was found by ELISA when using PBMCs from patients who had fully recovered from SARS, but not from normal individuals when cultured with SARS CoV S peptides. Further studies demonstrated that the frequency of IFN γ producing cells in PBMCs from fully recovered SARS patients was significantly higher than that in the PBMCs from normal controls( P <0.05) after stimulation with SARS CoV S peptides. In contrast, no markedly difference in the production and expression of IFN γ between the recovered patients and normal individuals was observed when the PBMCs were stimulated with polyclonal stimuli(PMA+ionomycin). Conclusion SARS CoV S antigen specific memory T cells persisted for several months in vivo and displayed the capacity to secrete IFN γ upon subsequent stimulation with SARS CoV S peptides.