结核分枝杆菌PstS1和HspX蛋白的免疫反应性及诊断价值评价

Immunoreactivity and diagnostic value of Mycobacterium tuberculosis PstS1 and HspX

目的:评价结核分枝杆菌PstS1和HspX蛋白的体液和细胞免疫反应性,为结核病免疫学诊断和疫苗候选抗原的筛选提供参考。方法:利用分子克隆表达和Ni 2+亲和层析技术纯化获得重组目的蛋白PstS1和HspX。收集健康志愿者和结核分枝杆菌感染志愿者血液样本及其背景流行病学资料,以重组PstS1和HspX蛋白作为抗原,进行酶联免疫吸附试验(ELISA)和酶联免疫斑点试验(ELISPOT)分别检测特异性IgG抗体和分泌IFN-γ的抗原特异性T淋巴细胞。对数据进行统计学分析,评价重组PstS1和HspX蛋白的体液和细胞免疫反应性。 结果:重组PstS1和HspX蛋白均能特异性刺激结核分枝杆菌感染者体内较多的效应T细胞分泌IFN-γ,结核分枝杆菌感染组与健康对照组的检测结果差异有统计学意义( P<0.01);重组PstS1和HspX蛋白作为ELISPOT诊断抗原的特异度和灵敏度分别为92.11%(35/38)和65.96%(31/47),68.42%(26/38)和91.49%(43/47)。重组PstS1和HspX蛋白也具有一定的体液免疫反应性,但仅HspX蛋白特异性抗体水平在结核分枝杆菌感染组与健康对照组间的差异有统计学意义( P<0.05)。 结论:重组PstS1和HspX蛋白均具有较好的细胞免疫反应性,属于细胞免疫优势抗原。两者均具有较好的细胞免疫诊断性能,同时也是较好的潜在抗结核疫苗候选抗原。

Objective To evaluate the humoral and cellular immunoreactivity of recombinant Mycobacterium tuberculosis(M.tuberculosis)PstS1 and HspX protein antigens in order to provide reference for immunodiagnosis of tuberculosis and screening of candidates for vaccine antigens.Methods Purified recombinant M.tuberculosis PstS1 and HspX proteins were obtained using molecular cloning expression and Ni2+affinity chromatography.Blood samples and epidemiological data of healthy individuals and patients with M.tuberculosis infection were collected.Specific IgG antibodies and IFN-γ-producing antigen-specific T cells were respectively detected by enzyme-linked immunosorbent assay(ELISA)and enzyme-linked immunospot assay(ELISPOT)with the recombinant proteins used as antigens.The humoral and cellular immunoreactivity of the recombinant PstS1 and HspX proteins were assessed with statistical analysis of data.Results Both the recombinant PstS1 and HspX proteins could induce the secretion of IFN-γby more specific effector T cells in patient with M.tuberculosis infection,and the differences between the infection and healthy control groups were statistically significant(P<0.05).The specificity and sensitivity of the recombinant PstS1 and HspX as the diagnostic antigens of ELISPOT were 92.11%(35/38)and 65.96%(31/47),and 68.42%(26/38)and 91.49%(43/47),respectively.The two proteins also possessed some humoral immunoreactivity,but statistically significant difference was only observed in the HspX-specific antibody level between the two groups(P<0.05).Conclusions Both the recombinant PstS1 and HspX proteins had good cellular immunoreactivity and were the immunodominant antigens of cellular immunity.They performed well in cellular immunodiagnosis and were good potential candidate antigens for anti-tuberculosis vaccines.