经鼻黏膜给予MBP68-86和87-99协同免疫预防Lewis大鼠EAE的实验研究

Inhibiton of experimental autoimmune encephalomyelitis in Lewis rats by nasal administration of encephalitogenic MBP peptides:synergistic effects of MBP68-86 and 87-99

目的探讨鼻黏膜给予MBP68-86和87-99协同免疫预防Lewis大鼠实验性自身免疫性脑脊髓炎(EAE)的作用。方法合成3条不同的碱性髓鞘蛋白(MBP)多肽(MBP68-86、87-99和非致脑炎性肽段110-128),在用豚鼠MBP(gp-MBP)加弗氏完全佐剂免疫Lewis大鼠前的11、10、9、8和7d,经鼻黏膜分别给予MBP多肽,观察其对EAE的保护作用。结果致脑炎性肽段MBP68-86和87-99都有保护作用,其中MBP68-86的保护作用更强;而MBP110-128没有保护作用。鼻黏膜给予MBP68-86+87-99的混合物,在相对低的剂量可完全阻断gp-MBP引发的EAE。淋巴细胞增殖实验和IFN-γELISPOT检测显示,与鼻黏膜给予大鼠MBP110-128组相比,鼻黏膜给予大鼠MBP68-86+87-99可降低T细胞对于MBP的反应性,淋巴结单核细胞中表达IFN-γ和TNF-αmRNA的细胞数减少,而两组表达TGF-β及IL-4mRNA的淋巴细胞数都低。结论鼻黏膜给予致脑炎性MBP多肽能够导致抗原特异性T细胞耐受,对gp-MBP引发的EAE提供不完全的保护,MBP68-86和MBP87-99具有协同作用。鼻黏膜给予多肽引发的免疫耐受与非调节机制有关。

AIM： To explore the synergistic effect of MBP68-86 and 87-99, on the inhibition of experimental autoimmune encephalomyelitis （EAE） in Lewis rat by nasal administration. METHODS： Three different MBP peptides （MBP68-86, 87-99, and the non-encephalitogenic peptide 110-128） were synthesized and administrated nasally to Lewis rat on day-11, -10, -9, -8 and -7 prior to immunization with the guinea pig MBP （gp-MBP） ＋ CFA, which was used to induce EAE. The protective effect on Lewis rat from EAE by the MBP peptides was evaluated. RESULTS： Protection was achieved with the encephalitogenic peptides MBP68-86 and 87-99, MBP68-86 being more potent, but not with MBP 110-128. Neither MBP68-86 nor 87-99 used alone conferred complete protection to gp-MBP-induced EAE. In contrast, nasal administration of a mixture of MBP68-86 and 87-99 completely blocked gp-MBP-induced EAE even at lower dosage than being used alone. Rats tolerized with MBP68-86 ＋ 87-99 nasally showed decreased T cell responses to MBP, reflected by lymphocyte proliferation and IFN-γ ELISPOT assays. Rats tolerized with MBP68-86 ＋ 87-99 also had abrogated MBP-reactive IFN-γ and TNF-α mRNA expression in lymph node cells compared to rats receiving MBP110-128 nasally, while similar low levels of MBP-reactive TGF-β and IL-4 mRNA expressing cells were observed in the two groups. CONCLUSION： Nasal administration of encephalitogenic MBP peptides can induce antigen-specific T cell tolerance and confer incomplete protection to gp-MBP- induced EAE, and MBP 68-86 and 87-99 have synergistic effecs, Non-regulatory mechanisms are proposed to be responsible for tolerance development after nasal peptide administration.