健康人外周血白念珠菌果糖二磷酸醛缩酶的抗原特异性T细胞检测

Detection of Candida albicans fructose bisphosphate aldolase antigen-specific T cells in healthy individuals by ELISPOT assay

目的侵袭性念珠菌病临床致死率较高,文中旨在研究白念珠菌免疫优势抗原1,6-果糖二磷酸醛缩酶(Fba)的细胞免疫应答类型,以评估其在侵袭性念珠菌病中是否具有保护性细胞免疫功能。方法建立检测健康人外周血单个核细胞(PBMC)中白念珠菌Fba抗原特异性T淋巴细胞分泌干扰素γ(IFN-γ)、白细胞介素-4(IL-4)与白细胞介素-17A(IL-17A)的酶联免疫斑点法(ELISPOT)。用白念珠菌重组抗原Fba为刺激物,检测26名健康人外周血PBMC中分泌IFN-γ、IL-4和IL-17A的阳性斑点形成细胞(SFC)频数。结果 Fba刺激后,26名健康人分泌IFN-γ、IL-4和IL-17A的频数分别为23.00(9.75,42.50)个、0(0,0.25)个和1.5(0.75,8.25)个,三者间两两比较差异均有统计学意义(P<0.01)。IFN-γ、IL-4和IL-17A的应答率分别为100%(26/26)、15.38%(4/26)和76.92%(20/26),IFN-γ和IL-17A的应答率显著高于IL-4应答率(P<0.01)。其中Fba刺激后产生强IFN-γ应答(SFC≥20)者占57.69%(15/26),而产生IL-17A强应答者1人,无人产生强IL-4应答。健康受试者PBMC应答同时产生Th1和Th17型应答者占65.38%(17/26);其中19.23%(5/26)的受试对象仅产生Th1型细胞免疫应答,无受试对象单独产生Th2型细胞免疫应答。结论白念珠菌特异性抗原Fba诱导的T细胞免疫以Th1型和Th17型为主,提示该抗原将产生保护性细胞免疫应答,具有成为理想疫苗的潜能。

Objective Invasive candidiasis is associated with a significant mortality clinically. The purpose of this study was to observe the T cells immune response to fructose bisphospbate aldolase （ Fba）, an immunodominant antigen of Candida albicans, and determine whether the antigen has the possibility of priming cellular immune protection in invasive candiasis. Methods Using ELlS- POT assay, we determined the frequencies of positive spot-forming cells （SFCs） of Fba antigen-specific T cells secreting IFN-γ, IL-4 and IL-17A in the peripheral blood mononuclear ceils （PBMCs） of 26 healthy individuals. Results After Fba stimulation, the fre- quencies of positive SFCs of IFN-γ, IL-4 and IL-17A in the 26 healthy subjects were 23 （9.75, 42.50）, 0 （0, 0.25） and 1.5 （0.75, 8.25）, respectively, with statistically significant differences among the three （P〈0. 01 ）. The response rates of IFN-γ （100%[26/26] ） and IL-17A （76.92% [20/26] ） were significantly higher than that of IL-4 （15.38% [4/26] ） （P〈0.01）. Fba-induced strong response （SCFs ≥20） for IFN-γ was observed in 57.69% （15/26） of the healthy individuals, that for IL-17A in only 1, while that for IL-4 in none. Responses of both Thl and Th17 cells to Fba were found in 65.38% （17/26） of the subjects, that of Thl cells in 19.23% （5/ 26）, but that of Th2 cells in none. Conclusion Fba of Candida albicans can induce immunodominant responses of Thl and Th17 cellsand is a potential vaccine against invasive candiasis.