کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9141914 | 1163886 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
IgG naturally occurring antibodies stabilize and promote the generation of the alternative complement pathway C3 convertase
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کلمات کلیدی
VBSIVIgnAbsMPGNNaturally occurring antibodiesC3 Nephritic factor - C3 فاکتور خونیantibodies - آنتی بادی هاinflammation - التهاب( توروم) Human - انسانautoimmunity - خودایمنیveronal-buffered saline - فلوئور بافر فلوئورComplement - متممalternative pathway of complement - مسیر جایگزین مکملmembranoproliferative glomerulonephritis - گلومرولونفریت غشایی غشایی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شناسی مولکولی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Normal human IgG contains naturally occurring anti-C3 antibodies (anti-C3 NAbs) that have been proposed to regulate complement amplification. Here, we report a novel procedure for anti-C3 NAb purification. Pooled human IgG was fractionated on a DEAE column prior to affinity chromatography on IgG and then on C3. Anti-C3 NAbs co-purified with anti-F(abâ²)2 NAbs. In a refined protocol, IgG fractions were absorbed on Fc, F(abâ²)2, and C3, which allowed to isolate the directly accessible NAbs and to remove IgG hinge-region-specific NAbs. Since a substantial fraction of total anti-C3 NAbs in whole IgG pre-existed as complexes, IgG that did not bind to the three affinity columns was treated with urea and the affinity chromatography repeated to collect the dissociated NAbs. The urea-accessible anti-F(abâ²)2 NAbs were rather pure but anti-C3 NAbs yet contained substantial amounts of anti-F(abâ²)2 NAbs. Anti-C3 NAbs showed up to 400-fold and anti-F(abâ²)2 NAbs, up to 30-fold enrichment as compared to pooled normal human IgG. Anti-C3 NAb preparations exhibited nephritic factor activity that was up to 60 times stronger than that of total IgG from a patient with membranoproliferative glomerulonephritis type 2. In addition, anti-C3 NAbs promoted C3 convertase generation, when added to the convertase precursor or during convertase assembly, suggesting a non-nephritic-factor mechanism. Factors H and I reduced the overall level of activity but had no influence on the NAb dose-response curve meaning that NAbs did not interfere with factor H binding. Convertase promoting activity during assembly correlated with the content of anti-C3 NAbs in NAb complexes. In conclusion, anti-C3 NAbs associated with framework-specific anti-idiotypic NAbs stabilize C3 convertase and promote its generation but their activity is compensated for in whole IgG.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Molecular Immunology - Volume 42, Issue 11, July 2005, Pages 1393-1403
Journal: Molecular Immunology - Volume 42, Issue 11, July 2005, Pages 1393-1403
نویسندگان
Emiliana Jelezarova, Hans U. Lutz,