来自有症状和无症状个体的芽囊原虫3型的免疫原性和抗原异质性。

Sheela Devi S, Suresh K

Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.

Trop Biomed. 2019 Mar 1;36(1):234-244.

Blastocystis sp. subtype 3 (ST3) has been implicated previously to be phenotypically heterogeneous between isolates from symptomatic and asymptomatic persons in previous studies. The aim of this study is to identify the immunogenic and antigenic heterogeneity among three different isolates of Blastocystis sp. ST3 isolated from asymptomatic and symptomatic individuals. Immunogenic and antigenic profile of ST3 isolates was assessed through splenocyte proliferation, cytokine assessment and antibody measurements. The total IgG antibody responses in mice immunised with symptomatic (0.736±0.033) and asymptomatic (0.426±0.025) of ST3 Blastocystis sp. were significantly higher compared to the controls respectively. High secretions of IgG antibody mixture of IgG1/IgG2a antibodies were detected in sera of mice immunised with symptomatic and asymptomatic solubilised Blastocystis sp. Antigen (Blastocystis-Ag). Predominant IgG1 production was detected higher in mice injected with Blastocystis sp. ST 3 from asymptomatic individuals (0.148±0.016) (P<0.05) whereas predominant IgG2a production was detected higher in mice injected with the same subtype but from the symptomatic individuals (0.355±0.021). This data was supported by the production of significantly higher Th1 (IFNγ and IL-2) response (393.56±49.21) and (628.89±31.06) respectively in symptomatic isolates compared to Th2 (IL-4 and IL-10) response (93±7.85) and (103.22±11.33) in asymptomatic isolates after in-vitro stimulations. Splenocyte stimulation index (SI) was detected higher in symptomatic Blastocystis-Ag group. This study is the first to demonstrate antigenic and immunogenic heterogeneity among ST3 symptomatic and asymptomatic Blastocystis-Ag with symptomatic isolates being highly immunogenic and antigenic. No significant variations among the three isolates of asymptomatic and symptomatic groups. The study supports the suggestion from previous study that surface variations between symptomatic and asymptomatic isolates as well their distinct phenotypic variation despite being the same subtype may have caused the differences in the distinct immune responses.

先前的研究表明，人芽囊原虫3型（ST3）在有症状和无症状个体的分离株之间存在表型异质性。本研究的目的是确定从无症状和有症状个体中分离出的三种不同人芽囊原虫ST3分离株之间的免疫原性和抗原异质性。通过脾细胞增殖、细胞因子评估和抗体测量来评估ST3分离株的免疫原性和抗原谱。用有症状（0.736±0.033）和无症状（0.426±0.025）的人芽囊原虫ST3免疫的小鼠中，总IgG抗体反应分别显著高于对照组。在用有症状和无症状的可溶性人芽囊原虫抗原（芽囊原虫抗原）免疫的小鼠血清中检测到IgG1/IgG2a抗体的IgG抗体混合物高分泌。在注射来自无症状个体的人芽囊原虫ST 3的小鼠中检测到较高的主要IgG1产生（0.148±0.016）（P<0.05），而在注射相同亚型但来自有症状个体的小鼠中检测到较高的主要IgG2a产生（0.355±0.021）。与无症状分离株中的Th2（IL-4和IL-10）反应（93±7.85）和（103.22±11.33）相比，有症状分离株中Th1（IFNγ和IL-2）反应分别显著更高（393.56±49.21）和（628.89±31.06），这一数据支持了上述结果。体外刺激后，有症状的芽囊原虫抗原组中脾细胞刺激指数（SI）更高。本研究首次证明了ST3有症状和无症状芽囊原虫抗原之间的抗原性和免疫原性异质性，有症状分离株具有高度免疫原性和抗原性。无症状和有症状组的三种分离株之间无显著差异。该研究支持了先前研究的建议，即有症状和无症状分离株之间的表面差异以及尽管是同一亚型但其明显的表型变异可能导致了不同免疫反应的差异。