绿脓杆菌制剂与IL-12在诱导人NK细胞IFN-γ产生中的协同作用

探讨绿脓杆菌制剂(piliated Pseudomonas Aeruginosa,PPA)与IL-12协同诱导人PBMC和NK细胞IFN-γ的产生。分离健康人PBMC和纯化NK细胞分别与培养液、PPA、IL-12或PPA+IL-12共同培养,利用酶联免疫吸附法(ELISA)检测无细胞培养上清中IFN-γ的水平。同时采用流式细胞仪在单个细胞水平上分析PPA和IL-12诱导IFN-γ产生的淋巴细胞亚群。结果显示,单独应用亚适剂量的IL-12或PPA刺激人PBMC或纯化NK细胞,不能诱导或只能诱导低水平IFN-γ的产生。当PPA和IL-12共同与人PBMC或纯化NK细胞孵育后,PPA呈时间和剂量依赖性与IL-12协同诱导PBMC和纯化NK细胞产生大量IFN-γ。细胞亚群分析的结果表明,PPA和IL-12协同诱导CD56+NK细胞产生IFN-γ,但对CD4+T和CD8+T细胞无明显作用。PPA与IL-12协同促进NK细胞IFN-γ的产生,提示PPA和IL-12能直接刺激NK细胞发生免疫应答。

The synergistic effect of the piliated Pseudomonas aeruginosa and interleukin-12 on the induction of IFN-γ production from human NK cells

To evaluate the effect of the piliated Pseudomonas aeruginosa(PPA) and interleukin-12(IL-12)on the secretion of IFN-γ from human PBMC and NK cells,PBMC or purified NK cells were co-cultivated with culture medium,PPA,IL-12 or PPA + IL-12,and the level of IFN-γ in the cell-free culture supernatants was measured by ELISA.The lymphocyte subsets producing IFN-γ were examined at single cell level by means of flow cytometry.It was demonstrated that application of suboptimal dose of PPA or IL-12 alone induced low or undetectable levels of IFN-γ by human PBMC or NK cells.However,use of PPA plus IL-12 showed a synergistic effect on the induction of high level of IFN-γ production from human PBMC in a dose and time-dependent manner.As demonstrated from the flow cytometry analysis,PPA plus IL-12 induced the production of IFN-γ from CD56+ NK cells,but not from CD4+ or CD8+ T cells.It is apparent that the synergistic effect of PPA and IL-12 on the production of IFN-γ from CD56+ NK cells reflects the fact that they can stimulate NK cells directly,so as to induce immune responses.