Ara J, Ali R
Department of Biochemistry, Faculty of Medicine, Aligarh, India.
Immunol Lett. 1992 Dec;34(3):195-200. doi: 10.1016/0165-2478(92)90213-8.
In vitro studies were carried out to determine if reactive oxygen species modified DNA molecules are the preferred antigen for anti-DNA antibodies found in SLE sera. Reactive oxygen species were generated by 254 nm irradiation of hydrogen peroxide. Single stranded breaks, decrease in Tm and modification of adenine (21.7%) and thymine (48%) were the major effects observed on native DNA fragments of 300 bp in length. The ROS-modified DNA showed increased binding with naturally occurring anti-DNA autoantibodies as compared to unmodified DNA fragments. These results were substantiated by competition ELISA. Measurement of binding with DNA fragments of varying size revealed considerably increased binding as the fragment size increased from 50 bp to 800 bp. The relative affinity of anti-DNA IgG for ROS-modified and native DNA fragments of 300 bp were in the order of 6.26 x 10(-8) M and 4.07 x 10(-8) M, respectively.
进行了体外研究，以确定活性氧修饰的DNA分子是否是系统性红斑狼疮（SLE）血清中抗DNA抗体的首选抗原。通过对过氧化氢进行254nm照射产生活性氧。观察到对300bp长的天然DNA片段的主要影响包括单链断裂、熔解温度（Tm）降低以及腺嘌呤（21.7%）和胸腺嘧啶（48%）的修饰。与未修饰的DNA片段相比，活性氧修饰的DNA与天然存在的抗DNA自身抗体的结合增加。这些结果通过竞争酶联免疫吸附测定（ELISA）得到证实。对不同大小DNA片段结合的测量显示，随着片段大小从50bp增加到800bp，结合显著增加。抗DNA IgG对300bp的活性氧修饰DNA片段和天然DNA片段的相对亲和力分别为6.26×10⁻⁸M和4.07×10⁻⁸M。
