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Immunopathology of desialylation: human plasma lipoprotein(a) and circulating anti-carbohydrate antibodies form immune complexes that recognize host cells

Immunopathology of desialylation: human plasma lipoprotein(a) and circulating anti-carbohydrate... Human plasma lipoprotein(a) [Lp(a)], the dominant lipoprotein in atherosclerotic plaques, contains an apo(a) subunit of variable size linked to the apoB subunit of a low-density lipoprotein (LDL) molecule. Circulating lipoprotein immune complexes (ICs) assayed by ELISA using microplate-coated anti-apo(a) or anti-apoB antibody for capture and peroxidase-labelled anti-human immunoglobulins as probe consisted mostly of Lp(a) despite several-fold excess of LDL over Lp(a) in plasma. Microplate coating of plasma lipoprotein IC and probing with antibodies to apo(a) and apoB also revealed negligible presence of LDL compared to Lp(a). Peanut agglutinin specific to desialylated O-glycans bound significantly more to Lp(a) recovered after urea dissociation of IC than to free Lp(a). Plasma lipoproteins separated by ultracentrifugation and desialylated by neuraminidase formed IC with naturally occurring antibodies in normal plasma. These de novo ICs agglutinated desialylated but not normal human RBC in proportion to the polyagglutinin antibody titre of plasma used, suggesting availability of multiple unoccupied binding sites on the participating antibodies even after IC formation. Agglutination was inhibitable by galactosides and decreased 4–8 fold if precursor lipoprotein was selectively depleted of Lp(a), showing agglutinating ICs were contributed mainly by desialylated Lp(a) and galactose-specific antibodies. IC was 2 fold more agglutinating if lipoproteins used contained smaller rather than larger Lp(a) molecules of the same number. Small size/high plasma concentration Lp(a) phenotype and neuraminidase-releasing diseases including diabetes are risk factors for vascular disorders. Results suggest a possible route of Lp(a) attachment to vascular cells that offer terminal galactose on surface glycans following desialylation. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Molecular and Cellular Biochemistry Springer Journals

Immunopathology of desialylation: human plasma lipoprotein(a) and circulating anti-carbohydrate antibodies form immune complexes that recognize host cells

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References (48)

Publisher
Springer Journals
Copyright
Copyright © 2015 by Springer Science+Business Media New York
Subject
Life Sciences; Biochemistry, general; Medical Biochemistry; Oncology; Cardiology
ISSN
0300-8177
eISSN
1573-4919
DOI
10.1007/s11010-015-2332-3
pmid
25633186
Publisher site
See Article on Publisher Site

Abstract

Human plasma lipoprotein(a) [Lp(a)], the dominant lipoprotein in atherosclerotic plaques, contains an apo(a) subunit of variable size linked to the apoB subunit of a low-density lipoprotein (LDL) molecule. Circulating lipoprotein immune complexes (ICs) assayed by ELISA using microplate-coated anti-apo(a) or anti-apoB antibody for capture and peroxidase-labelled anti-human immunoglobulins as probe consisted mostly of Lp(a) despite several-fold excess of LDL over Lp(a) in plasma. Microplate coating of plasma lipoprotein IC and probing with antibodies to apo(a) and apoB also revealed negligible presence of LDL compared to Lp(a). Peanut agglutinin specific to desialylated O-glycans bound significantly more to Lp(a) recovered after urea dissociation of IC than to free Lp(a). Plasma lipoproteins separated by ultracentrifugation and desialylated by neuraminidase formed IC with naturally occurring antibodies in normal plasma. These de novo ICs agglutinated desialylated but not normal human RBC in proportion to the polyagglutinin antibody titre of plasma used, suggesting availability of multiple unoccupied binding sites on the participating antibodies even after IC formation. Agglutination was inhibitable by galactosides and decreased 4–8 fold if precursor lipoprotein was selectively depleted of Lp(a), showing agglutinating ICs were contributed mainly by desialylated Lp(a) and galactose-specific antibodies. IC was 2 fold more agglutinating if lipoproteins used contained smaller rather than larger Lp(a) molecules of the same number. Small size/high plasma concentration Lp(a) phenotype and neuraminidase-releasing diseases including diabetes are risk factors for vascular disorders. Results suggest a possible route of Lp(a) attachment to vascular cells that offer terminal galactose on surface glycans following desialylation.

Journal

Molecular and Cellular Biochemistry – Springer Journals

Published: Jan 30, 2015

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