Kinoshita G, Purcell A W, Keech C L, Farris A D, McCluskey J, Gordon T P
Department of Immunology, Allergy & Arthritis, Flinders Medical Centre and Flinders University, Adelaide, South Australia.
Clin Exp Immunol. 1999 Feb;115(2):268-74. doi: 10.1046/j.1365-2249.1999.00794.x.
We have used a murine model of experimental anti-Ro(SS-A) autoimmunity to dissect additional intermolecular interactions between the 52-kD Ro (Ro52) and 60-kD Ro (Ro60) autoantigens and molecular chaperones. Immune responses to members of the heat shock protein hsp70 and hsp90 families were measured by immunoblotting and ELISA in sera from mice immunized and boosted with purified recombinant Ro52, Ro60 and La (SS-B). All Ro52 and Ro60 immune sera immunoblotted the inducible glucose-regulated protein grp78 and hsp70 species but not constitutive hsc70 or hsp90. The kinetics of antibody production and reciprocal affinity purification experiments indicated that the grp78 and hsp70 responses were cross-reactive but distinct from immune responses to the primary Ro52 and Ro60 immunogens and the endoplasmic reticulum (ER)-resident chaperone calreticulin. No responses to molecular chaperones were detected in the La-immunized mice. Control immunizations indicated that the recruited grp78 and hsp70 responses were specific for the Ro proteins and not due to immunization with denatured protein. The rapid spreading of immunity to the inducible grp78 and hsp70 in Ro52- and Ro60-immunized mice suggests that these components may co-localize and physically associate under certain physiological conditions which may promote autoimmunization. The potential importance of the ER-resident chaperones grp78 and calreticulin is further supported by their co-localization with Ro in small apoptotic membrane blebs and the finding of a novel putative grp78 binding motif in the carboxyl-terminal region of Ro52.
我们使用了实验性抗Ro(SS-A)自身免疫的小鼠模型，以剖析52-kD Ro（Ro52）和60-kD Ro（Ro60）自身抗原与分子伴侣之间的其他分子间相互作用。通过免疫印迹法和酶联免疫吸附测定法（ELISA），检测了用纯化的重组Ro52、Ro60和La（SS-B）免疫并加强免疫的小鼠血清中对热休克蛋白hsp70和hsp90家族成员的免疫反应。所有Ro52和Ro60免疫血清都能免疫印迹诱导型葡萄糖调节蛋白grp78和hsp70，但不能免疫印迹组成型hsc70或hsp90。抗体产生的动力学和相互亲和纯化实验表明，grp78和hsp70反应具有交叉反应性，但与对主要Ro52和Ro60免疫原以及内质网（ER）驻留伴侣钙网蛋白的免疫反应不同。在La免疫的小鼠中未检测到对分子伴侣的反应。对照免疫表明，募集的grp78和hsp70反应对Ro蛋白具有特异性，而不是由于用变性蛋白免疫所致。在Ro52和Ro60免疫的小鼠中，对诱导型grp78和hsp70的免疫迅速扩散，这表明这些成分在某些生理条件下可能共定位并发生物理关联，这可能促进自身免疫。内质网驻留伴侣grp78和钙网蛋白的潜在重要性进一步得到它们与Ro在小凋亡膜泡中共定位以及在Ro52羧基末端区域发现一个新的假定grp78结合基序的支持。
