The interaction of human plasma glycosaminoglycans with plasma lipoproteins. II. Hemagglutination studies.
Formalinized, tannic acid-treated sheep erythrocytes coated with low density lipoproteins (LSL) or apoprotein B (apo-B) are are agglutinated by anti-apo-B immunserum. Those coated with high density lipoproteins (HDL) or apoprotein A-I(apo-A-I) are agglutinated by anti-apo-A-I immunserum. These coated formocells have been used to study the interactions of lipoproteins and apoproteins with plasma glycosaminoglycans (GAG). The sulfate-rich species of plasma GAG agglutinates cells coated with LDL, HDL, apo-B, and apo-A-I at ionic concentrations above 0.15 M. The less-sulfated species of plasma GAG does not agglutinate the coated cells but inhibits the agglutination caused by the sulfate-rich species. Treatment of the sulfate-rich GAG with papain causes a reduction in molecular weight by one-half and also causes a loss of its agglutinating activity. These results suggest that the sulfate-rich plasma GAG, consisting of two glycan chains linked to a peptide backbone, cause agglutination by binding to two or more formocells. In contrast, the less-sulfated plasma GAG, consisting of single, short glycan chains, are incapable of causing agglutination but may prevent it by covering specific binding sites present on the coated cells.
D001059:Apoproteins / Q000276:immunology; D006025:Glycosaminoglycans / Q000097:blood*; D006386:Hemagglutination Tests; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism
D001059:Apoproteins; D006025:Glycosaminoglycans; D007106:Immune Sera; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008079:Lipoproteins, VLDL; D013431:Sulfates