多糖HCP-2对调节性B细胞的诱导作用机制研究

Allergic disease has been becoming the focus field of research for its high incidence among adults and children globally. Regulatory B cells (Breg) attracts much attention for its regulation on the balance of Th1/Th2, and the activation of TLR-4 could induce the mice splenic B cells into Breg. Our previous study indicated that a polysaccharide, HCP-2, isolated from Houttuynia cordata could activate human peripheral blood mononuclear cells by activating TLR-4 to modulate the immune response; oral administration of HCP-2 could improve the OVA induced airway allergy and restore the CD19(+)IL0(+) B cells back to the normal level in mice, which implied that HCP-2 possess the anti-allergy potential. We hypothesize that HCP-2 could induce differentiation of B cell into Breg by activating TLR-4 receptor. The variation allergic cytokines, featured CD antigens and related protein will be determined after co-culture HCP-2 with mice splenic B cells in vitro. After co-cultured with HCP-2, mice splenic B cells will be adoptively transferred into OVA-induced allergic airway inflammation mice model, and the modulation of HCP-2 on allergy in OVA-induced allergic airway inflammation mice model will be evaluated. The study focuses on the role of HCP-2 on the induction of Breg and underlying mechanism, and we hope this study will benefit the use of traditional Chinese Medicine in allergy treatment and prevention.

过敏性疾病发病率达30%，目前尚无根治的药物。调节性B细胞（Breg）通过分泌IL-10，诱导调节性T细胞分化，在抑制过敏中起重要作用。TLR-4激活可诱导B细胞分化为Breg，但其诱导机制有待进一步研究。中药在过敏性疾病治疗方面有着广泛应用，但中药对Breg的诱导作用尚不清楚。我们从鱼腥草中得到的单体多糖HCP-2，可激活人外周血单核细胞膜表面受体TLR-4；灌胃给药HCP-2可恢复CD19（+）IL-10（+）B细胞到正常小鼠水平，并显著改善小鼠气道过敏症状。我们设想HCP-2通过TLR-4诱导小鼠B细胞分化为Breg，进而诱导机体产生免疫耐受。本项目拟通过研究HCP-2对小鼠脾脏B细胞源IL-10和Breg特征CD抗原分化的影响，探讨HCP-2通过激活TLR4诱导小鼠脾脏B细胞分化为Breg的作用机制，以期为中药活性成分在诱导机体产生免疫耐受，调节呼吸道过敏的应用方面提供依据。

随着人们生活水平提高，过敏反应给患者带来长期的困扰。目前，临床治疗尚不能彻底地预防或治愈过敏反应。研究表明，调节性B细胞和调节性T细胞在调节机体免疫耐受，抑制过敏反应方面起到重要作。.本研究基于肠道菌群，探讨中药多糖对调节性B细胞和调节性T细胞分化的影响，阐明中药多糖对过敏性疾病的调节作用。本研究的主要内容：以小鼠呼吸道过敏炎症模型研究：（1）探讨HCP-2对小鼠脾脏B细胞分化的影响及对OVA诱导的气道高反应小鼠过敏症状的预防和调节作用；（2）基于GSP-2促进益生菌生长及对肠道微生物的影响，探讨GSP-2对调节性Treg细胞分化的诱导作用,阐明紫芝多糖GSP-2促进调节性Treg细胞分化，诱导机体免疫耐受，治疗过敏性哮喘的机制。.结果：（1）单体多糖HCP-2可以通过激活人周边单核血细胞（PBMC）膜表面TLR-4受体调节免疫；灌胃给药HCP-2治疗过敏性哮喘小鼠后，小鼠血清中特异性IgE和嗜酸性白细胞显著降低，并且脾脏中CD4+CD25+ T细胞比例显著增加，调节性B细胞恢复到接近正常对照组水平。（2）紫芝多糖灌胃给药治疗后，同小鼠呼吸道过敏性炎症模型组比较，小鼠血清OVA特异性IgE水平显著降低，气道高反应显著减弱，肺部炎症细胞显著降低，肺粘膜完整度较高、肺部炎症减轻，同模型组有显著性差异；免疫抑制因子IL-10上升，CD4+CD25+Foxp3+ T细胞比例显著升高。表明GSP-2灌胃给药小鼠可能诱导体内Treg分化，进而缓解过敏性呼吸道炎症症状。.本研究阐明多糖GSP-2和HCP-2可以体内诱导小鼠Treg分化，改善过敏性哮喘相关症状；本研究成果将有助于中药多糖的抗过敏临床应用。