Joussemet Béatrice, Vu Anh-Tuan, Sai Pierre, Bach Jean-Marie
Immuno-Endocrinology Unit, ENVN/INRA/University, ENVN, Atlanpôle-La Chantrerie, BP 40706, 44307 Nantes cedex 03, France.
Ann N Y Acad Sci. 2005 Jun;1051:613-25. doi: 10.1196/annals.1361.106.
Plasmid-DNA gene-gun immunization may be an efficient approach for investigating the role of skin dendritic cells (DCs) in type 1 diabetes (T1D) pathogenesis and the significance of the presentation of peptides that mimic autoantigenic epitopes in aggravating or modulating the autoimmune reaction. Gene-gun immunization has been described as producing long-lasting immune responses elicited by skin DCs, especially Langerhans cells (LCs). Therefore, we tested the immune response and diabetes modulation in nonobese diabetic (NOD) mice and in control BALB/c mice, by gene-gun administration of plasmid-DNA encoding (1) human 65 kDa glutamic acid decarboxylase (hGAD65) mimicking the crucial mouse autoantigen GAD65 (similarity of 95.7%) or (2) beta-galactosidase (betaGAL) as a negative control. Expression of GAD and betaGAL in skin of pc-GAD- and pc-LacZ-injected mice, respectively, was confirmed. It was surprising that both pc-LacZ-injected BALB/c and NOD mice exhibited a betaGAL-specific Th1 immune response: spleen cells of pc-LacZ mice proliferated specifically to betaGAL (P < 10(-4)) and secreted significant amounts of IFNgamma (P < 10(-4)). pc-LacZ mice also developed a betaGAL-specific Th1-related (IgG2a/2c) and Th2-related (IgG1) humoral response. Although pc-GAD BALB/c mice showed Th2-related GAD-specific IgG1 production and a significant secretion of IL4 (P < .03), pc-GAD NOD mice did not generate either an antibody response or a T cell response specific to GAD. Moreover, gene-gun immunization encoding hGAD65 did not clearly modulate diabetes onset in NOD mice. This absence of detectable GAD-specific response may implicate skin DC deficiencies in NOD mice. The gene-gun technique could thus provide an interesting model for studying skin DC abnormalities in NOD mice and their potential implication of presenting mimetic peptides that modulate the autoimmune response in T1D.
质粒DNA基因枪免疫法可能是一种有效的方法，用于研究皮肤树突状细胞（DCs）在1型糖尿病（T1D）发病机制中的作用，以及模拟自身抗原表位的肽段递呈在加重或调节自身免疫反应中的意义。基因枪免疫法已被描述为可产生由皮肤DCs，尤其是朗格汉斯细胞（LCs）引发的持久免疫反应。因此，我们通过基因枪给予编码（1）模拟关键小鼠自身抗原GAD65（相似度为95.7%）的人65kDa谷氨酸脱羧酶（hGAD65）或（2）β-半乳糖苷酶（βGAL）作为阴性对照的质粒DNA，来检测非肥胖糖尿病（NOD）小鼠和对照BALB/c小鼠的免疫反应及对糖尿病的调节作用。分别证实了pc-GAD和pc-LacZ注射小鼠皮肤中GAD和βGAL的表达。令人惊讶的是，pc-LacZ注射的BALB/c和NOD小鼠均表现出βGAL特异性的Th1免疫反应：pc-LacZ小鼠的脾细胞对βGAL特异性增殖（P < 10^(-4)）并分泌大量IFNγ（P < 10^(-4)）。pc-LacZ小鼠还产生了βGAL特异性的Th1相关（IgG2a/2c）和Th2相关（IgG1）体液反应。尽管pc-GAD BALB/c小鼠表现出Th2相关的GAD特异性IgG1产生及IL4的显著分泌（P < 0.03），但pc-GAD NOD小鼠未产生针对GAD的抗体反应或T细胞反应。此外，编码hGAD65的基因枪免疫法并未明显调节NOD小鼠的糖尿病发病。这种未检测到的GAD特异性反应可能意味着NOD小鼠存在皮肤DC缺陷。因此，基因枪技术可为研究NOD小鼠皮肤DC异常及其在递呈调节T1D自身免疫反应的模拟肽段中的潜在作用提供一个有趣的模型。
