Effect of TNF gene polymorphism on autoimmune disease

肿瘤坏死因子基因与人和小鼠的主要组织相容性复合体紧密连锁。在小鼠肿瘤坏死因子α基因启动子区域，肿瘤坏死因子单倍型之间存在一种简单的序列长度多态性(微卫星DNA多态)。为了探讨肿瘤坏死因子基因多态性与肿瘤坏死因子产生程度的关系，我们引入了B10.PL(H-2^u：k^UA^UE^uTFm^dd)和NZB(H-2^d：k^da^dTFm^d)的单倍型，以及从B6(H-2^b：k^Ba^b：k^Ba^b)到NZW(H-2^z：k^UA：k^UE^uTf^Zd)的单倍型，建立了NZW.PL(H-2^u：k^UA uE^uBD^d)、NZW.H-2^d(H-2^d：k^da^b：k^b)和NZW.H-2^b(H-2^d：k^A uuE uE uBD^d)单倍型。然后，我们比较了NZW、NZW.PL、NZW.H-2^d和NZW.H-2^b株在体外经脂多糖和干扰素刺激的巨噬细胞产生的肿瘤坏死因子的量以及血清中的肿瘤坏死因子水平。与其他三株NZW.PL、NZW.H-…相比，NZW的巨噬细胞产生肿瘤坏死因子的量要少得多，血清中的肿瘤坏死因子水平也低得多更多的是2^d和NZW.H-2^b品系的小鼠。这些结果表明，肿瘤坏死因子基因多态性影响肿瘤坏死因子水平，与单倍型相比，肿瘤坏死因子αz为低水平的肿瘤坏死因子单倍型，自身免疫性疾病的发生与小鼠MHC单倍型H-2密切相关。根据我们以前的研究，我们认为II类分子，特别是I-A，与这种H-2限制有关。然而，有报道称可能与H-2连锁的肿瘤坏死因子基因有关，单倍型NZW小鼠低水平的肿瘤坏死因子水平是(NZB*NZW)F1小鼠发生严重自身免疫性疾病的关键。然后，我们利用已建立的同源菌株，研究了肿瘤坏死因子基因多态与自身免疫性疾病的关系。与(NZB*NZW.H-2^d)F1和(NZB*NZW.H-2^d)F1小鼠相比，(NZB*NZW)F1小鼠的腹腔巨噬细胞产生的肿瘤坏死因子和血清中的肿瘤坏死因子水平显著降低。在自身免疫性疾病方面，(NZB*NZW)F1小鼠的病情最严重，(NZB*NZW.PL)F1小鼠的病情略轻于(NZB*NZW)F1小鼠。相比之下，(NZB*NZW.H-2^d)F1小鼠的病情严重程度比另外两个F1品系小鼠要低得多。(NZB*NZW.PL)F1和(NZB*NZW.H-2^d)F1小鼠具有相同的肿瘤坏死因子单倍型，产生相同数量的肿瘤坏死因子。因此，我们得出结论，K、A和E的单倍型，而不是肿瘤坏死因子的单倍型，影响这些小鼠品系的自身免疫性疾病的严重程度。较少

TNF gene is tightly linked to major histocompatibility complex in both human and mouse. In the promoter region of mouse TNFalpha gene, there is a simple sequence length polymorphism (microsatelite DNA polymorphism) among TNF haplotypes. To investigate the relationship between TNF polymorphism and the degree of TNF production, we introduced TNF^d haplotype from B10.PL(H-2^u : K^uA^uE^uTNF^dD^d) and NZB(H-2^d : K^dA^dE^dTNF^dD^d), and TNF^b haplotype from B6(H-2^b : K^bA^bE^bTNF^b) to NZW(H-2^z : K^uA^uE^uTNF^zD^z), and established NZW.PL(H-2^u : K^uA^uE^uTNF^bD^d), NZW.H-2^d(H-2^d : K^dA^dE^dTNF^dD^d) and NZW.H-2^b(H-2^u : K^uA^uE^uTNF^dD^d) congenic strains. Then, we compared amounts of TNF produced by peritoneal macrophages in vitro stimulated with LPS and INF_<gamma>, and serum TNF levels among these NZW,NZW.PL,NZW.H-2^d and NZW.H-2^b strains. The NZW strains showed much smaller amount of TNF production by macrophages and also lower level of serum TNF than another three NZW.PL,NZW.H- … More 2^d and NZW.H-2^b strains of mice did. These results indicate that TNF gene polymorphism affects the TNF levels and that TNF^z is alow TNF haplotype, as compared with TNF^d of TNF^b haplotypes.The development of antoimmune disease is tightly linked to the haplotype of mouse MHC,H-2. Based on our previous studies, we suggested that class II molecules, especially I-A,relate to this H-2 restriction. There was, however, the report that TNF gene linked to H-2 may be involved and that low TNF level of TNF^z haplotype of NZW mice is critical for the development of severe autoimmune disease in (NZB*NZW)F1 mice. We then investigated the relationship between TNF polymorphism and autoimmune disease, using established congenic strains. TNF production by perioneal macrophages and serum TNF level were much decreased in (NZB*NZW)F1 mice, because of TNF^z haplotype derived from NZW,as compared with (NZB*NZW.PL)F1 and (NZB*NZW.H-2^d)F1 mice. As for autoimmune disease, (NZB*NZW)F1 mice developed the most severe disease and (NZB*NZW.PL)F1 mice a little milder than (NZB*NZW)F1 mice. In contrast, the disease severity in (NZB*NZW.H-2^d)F1 mice was much reduced, as compared with another two F1 strains. (NZB*NZW.PL)F1 and (NZB*NZW.H-2^d)F1 mice have the same TNF haplotype and produce the same amount of TNF.The haplotypes of K,A and E regions of H-2 are differ between these two F1 strains. Thus, we concluded that haplotypes of K,A,and E,but not that of TNF,affect the autoimmune disease severity in these mouse strains. Less