双类似物鼻黏膜耐受对实验性自身免疫性重症肌无力预防作用机制的研究

Prophylactic effects of nasal tolerance with dual analogue on experimental autoimmune myasthenia gravis in lewis rats

目的 观察双类似物 (Lys2 6 2 Ala2 0 7)对实验性自身免疫性重症肌无力 (EAMG)大鼠进行鼻黏膜耐受预防性给药后临床、免疫指标的变化并评价疗效 ,探讨鼻黏膜耐受对EAMG的预防作用机制。方法 建立Lewis大鼠EAMG模型 ,并在致敏前 10d(A组 ,10只 )及致敏当日 (B组 ,10只 )鼻腔给药 ,评价给药后A、B组及相应对照组CA组 (10只 )、CB组 (10只 )大鼠的临床症状并检测肌肉中乙酰胆碱受体 (AChR)含量 ,测定致敏第 4 2天血清抗AChR抗体IgG含量、第 5 0天淋巴结单个核细胞 (MNC)中针对AChR等特异性抗原的淋巴细胞增殖反应和CD4 + 及CD4 + CD2 5 + T细胞。结果 (1)A、B组急性期和慢性期临床症状明显轻于相应对照组 ,A组慢性期临床症状轻于B组 ;(2 )A、B组慢性期血清抗AChR抗体IgG含量 [分别为 (2 2 0± 3 4 ) μg/ml和 (2 9 4± 4 6 ) μg/ml],明显低于相应对照组 [CA组 (4 2 6± 4 4 ) μg/ml、CB组 (4 3 2± 5 5 ) μg/ml],且A组低于B组 (均P <0 0 1) ;(3)A、B组大鼠肌肉AChR含量丢失明显低于相应对照组 (均P <0 0 1) ,且A组低于B组 (P <0 0 5 ) ;(4 )A、B组较各自对照组针对AChR等特异性抗原的淋巴细胞增殖反应均明显受抑 (均P <0 0 1) ;(5 )A、B组淋巴结中的CD4 + CD2 5 + T细胞含量均明显高于各?

Objective To study the prophylactic effects of nasal tolerance with a dual analogue (Lys262-Ala207) on experimental autoimmune myasthenia gravis (EAMG) and observe the underlying mechanisms, the clinical and immunological changes in Lewis rats treated with dual analogue nasally. Methods The effects of the predetermined dosage of a dual analogue Lys262-Ala207 were compared at different time points, and the dual analogues or control peptides were given nasally before (Group A or CA) or on the day (Group B or CB) of immunization with acetylcholine receptor (AChR) in complete Freund's adjuvant for 10 consecutive days. The clinical scores were evaluated for 50 days after immunization. The levels of anti-AChR IgG in serum were tested by RIA. Proliferative responses of lymphocytes to no antigen, Lys262-Ala207, AChR, AChR-α100-116, MBP peptide, or Con A were tested. The numbers of mononuclear cells expressing CD4 and/or CD25 from lymph nodes were enumerated using flow cytometry. Results As compared with the corresponding control groups, Lewis rats in group A or B developed EAMG with reduced severity and loss of AChR within the neuromuscular junction. The levels of anti-AChR IgG (21.96±3.37 and 29.41±4.59) were also decreased. Proliferative responses were suppressed in response to antigen-specific stimulations in rats receiving dual analogue, whereas the numbers of CD4+CD25+ T cells were higher in group A (11.34%±1.62%) and B (8.68%±1.83%) than in their corresponding control groups. Conclusions Nasal administration with a dual analogue Lys262-Ala207, at two different time points before and on the day of immunization ameliorated muscular weakness in EAMG rats associated with decreased levels of anti-AChR IgG in serum, suppressed antigen-specific T cell proliferation and increased numbers of CD4+CD25+ T cells from lymph nodes as compared to rats receiving control peptides. The results of our study suggest that the mucosal tolerance with dual analogue should be served as an alternative maneuver in human MG.