Boulanger C, Chabot B, Ménard H A, Boire G
Département de Médecine, Faculté de Médecine, University of Sherbrooke, Québec, Canada.
Clin Exp Immunol. 1995 Jan;99(1):29-36. doi: 10.1111/j.1365-2249.1995.tb03468.x.
We report the existence of a novel autoantibody specificity linked to anti-Ro antibodies. Sera from two patients with anti-Ro ribonucleoprotein (RNP) antibodies also contained antibodies that immunoprecipitated specifically either the deproteinized RNA component of the RohY5 RNP particle, or intact in vitro transcribed hY5 RNA. No serum recognized specifically the other hY RNAs. A mutant hY5 RNA with additional nucleotides (nt) at both extremities was not immunoprecipitated, possibly because of altered secondary structure. Following digestion of hY5 RNA with ribonuclease T1, the smallest immunoprecipitable RNA fragments were 27 and 31 nt long, and respectively mapped to the 5' and 3' ends of hY5 RNA, excluding the La-binding region. Base pairing between the 27 and 31 nt long fragments was required for recognition by antibodies. Our data indicate that the epitope bound by anti-hY5 RNA antibodies is conformational. We have previously reported that most anti-Ro sera contain a population of antibodies specific for the RohY5 RNP. Since antibodies to the deproteinized hY RNAs within anti-Ro sera are also restricted to anti-hY5 RNA, a direct role for the human-specific RohY5 particles in the immunization process leading to the production of anti-Ro antibodies is suggested.
我们报告了一种与抗Ro抗体相关的新型自身抗体特异性的存在。两名患有抗Ro核糖核蛋白（RNP）抗体的患者血清中还含有能特异性免疫沉淀RohY5 RNP颗粒的脱蛋白RNA成分或完整的体外转录hY5 RNA的抗体。没有血清能特异性识别其他hY RNA。两端带有额外核苷酸（nt）的突变hY5 RNA未被免疫沉淀，可能是由于二级结构改变。用核糖核酸酶T1消化hY5 RNA后，最小的可免疫沉淀RNA片段长度分别为27和31 nt，分别定位到hY5 RNA的5'和3'末端，但不包括La结合区域。27和31 nt长的片段之间的碱基配对是抗体识别所必需的。我们的数据表明，抗hY5 RNA抗体结合的表位是构象性的。我们之前曾报道，大多数抗Ro血清中含有一群对RohY5 RNP具有特异性的抗体。由于抗Ro血清中针对脱蛋白hY RNA的抗体也仅限于抗hY5 RNA，因此提示人类特异性RohY5颗粒在导致抗Ro抗体产生的免疫过程中起直接作用。
