THE MECHANISM OF NEPHRITOGENIC ANTI-DNA ANTIBODY PRODUCTION IN LUPUS NEPHRITIS

本研究的目的是阐明产生人肾源性抗dna抗体的抗原触发机制。我们发现一种人单克隆肾源性O-81抗dna抗体与内质网应激诱导蛋白（Herp.1）结合。采用dna固定化琼脂糖和疱疹固定化琼脂糖，分别从活动性狼疮性肾炎患者身上获得抗dna抗体和抗疱疹抗体。狼疮抗dna抗体与疱疹结合。此外，抗herp抗体对dna有特异性结合。每只6周龄BALB/c雌性小鼠腹腔注射Herp或鸡蛋溶菌酶（HEL）免疫。在BALB/c小鼠中，用Herp而非HEL免疫可引起抗dsdna和抗ssdna抗体，并在肾小球中形成IgG沉积。用单克隆抗疱疹抗体对SLE患者和健康人的pbl进行染色。疱疹在活动性SLE患者的pbl中自发表达，但在健康受试者的pbl中自发表达。在没有任何刺激的情况下，在体外培养72小时内观察SLE PBLs中Herp的表达。健康pbl中未见Herp表达。为了评估Herp的抗原性，将pbl与Herp一起培养6天，用ELISPOT法测定产生抗dna抗体的克隆数量。在体外用Herp刺激活动性SLE患者的pbl中产生抗dna抗体的克隆数量增加，但用HEL或dsDNA刺激则没有。非活动性SLE患者或健康受试者的pbl对疱疹的刺激没有反应。这些结果表明，一种可诱导的细胞内自身蛋白可能是人肾源性抗dna自身抗体的触发因素，在这种情况下，内质网应激可能被注意到。

The aim of the present study is to elucidate the antigenic trigger for the production of human nephritogenic anti-DNA antibodies. We found that a human monoclonal nephritogenic O-81 anti-DNA antibody bound to an endoplasmic reticulum stress-inducible protein, Herp.1. The anti-DNA or anti-Herp antibodies were obtained from the patients with active lupus nephritis by using a DNA-immobilized or a Herp-immobilized agarose, respectively. Lupus anti-DNA antibodies bound to Herp. Moreover, the anti-Herp antibodies showed specific binding to DNA.2. Each 6-week-old BALB/c female mouse was immunized intraperitoneally with Herp or Hen Egg Lysozyme (HEL). immunization with Herp, but not HEL, elicited anti-dsDNA as well as anti-ssDNA antibodies in BALB/c mice and formed the deposits of IgG in the renal glomeruli.3. The PBLs from SLE patients or healthy subjects were stained with a monoclonal anti-Herp antibody. Herp was spontaneously expressed in the PBLs of patients with active SLE, but in the PBLs of healthy subjects. The expression of Herp in the SLE PBLs was observed during the 72 hours in vitro culture without any stimulation. No expression of Herp was observed in healthy PBLs.4. To assess the antigenicity of Herp, the PBLs were cultured with Herp for 6 days, and the number of anti-DNA antibody producing clones was measured by ELISPOT assay. The number of anti-DNA antibody producing clones in the PBLs from active SLE patients increased in vitro after stimulation with Herp, but not with HEL or dsDNA. The PBLs form inactive SLE patients or healthy subjects did not respond to the stimulation with Herp.These results imply that an inducible intracellular self protein could be a trigger for human nephritogenic anti-DNA autoantibodies, where ER stress may be noted.