Concanavalin A-induced Aggregation of Human Blood Platelets

Summary

Concanavalin A (CON A) causes platelets to aggregate. A Ca⁺⁺-independent effect of CON A could be separated from a main effect which depends on Ca++. The main effect probably is a consequence of the CON A-induced platelet release reaction and therefore is platelet-specific. The weak residual effect observed in the presence of Na₂EDTA may be due to a similar mechanism as has been demonstrated for CON A-induced aggregations of several other normal and malignant transformed animal cells.

Na₂EDTA did not inhibit the carbohydrate-specific binding capacity of CON A. Therefore, Na₂EDTA appears not to demineralize the CON A molecules under these experimental conditions.

α-methyl-D-glucoside inhibits the Ca⁺⁺-independent as well as the Ca⁺⁺-dependent effect of CON A.

Pretreatment by neuraminidase stimulated the platelet aggregation induced by CON A. It is possible that removal of terminal sialic acid residues makes additional receptors accessible for the binding of CON A.

• References

• 1 Born G. V. R, Cross M. J. The aggregation of blood platelets. Journal of Physiology 1963; 168: 178
• 2 Bosmann H. B. Platelet adhesiveness and aggregation: II. surface sialic acid, glycoprotein: N-acetylneuraminic acid transferase, and neuraminidase of human blood platelets. Biochimica et Biophysica Acta 1972; 279: 456
• 3 Goldstein I. J, Reichert Ch. M, Misaki A, Gorin P. A. J. An “extension” of the carbohydrate binding specificity of Concanavalin A. Biochimica et Biophysica Acta 1973; 317: 500
• 4 György P, Jeanloz R. W, Nikolai H, von Zilliken P. Undialyzable growth factors for Lactobacillus bifidus var. pennsylvanicus. Protective effect of sialic acid bound to glycoproteins and oligosaccharides against bacterial degradation. European Journal of Biochemistry 1974; 43: 29
• 5 Haslam R. J. Role of ADP in the aggregation of human blood platelets by thrombin and by fatty acids. Nature 1964; 202: 765
• 6 Majerus P. W, BrodIe G.N. The binding of phytohemagglutinins to human platelet plasma membranes. Journal of Biological Chemistry 1972; 247: 4253
• 7 McKenzie G. H, Sawyer W. H, Nichol B. W. The molecular weight and stability of concanavalin A. Biochimica et Biophysica Acta 1971; 263: 283
• 8 Mitchell J. R. A, Sharp A. A. Platelet clumping in vitro. British Journal of Haematology 1964; 10: 78
• 9 Mori Y, Akedo H, Tanicaki Y. Changes induced by concanavalin A in morphological and adhesive properties of suspension cells. Experimental Cell Research 1973; 78: 360
• 10 Nachman R. L, Hubbard A, Ferris B. Iodination of the human platelet membrane. Studies of the major surface glycoprotein. Journal of Biological Chemistry 1973; 248: 2928
• 11 Noonan K. D, Burger M. M. The relationship of concanavalin A binding to lectin-initiated cell agglutination. Journal of Cell Biology 1973; 59: 134
• 12 O’Brien J. R. Platelet aggregation, Part II. Some results from a new method of study. Journal of Clinical Pathology 1962; 15: 446
• 13 Patscheke H, Brossmer R. Platelet release reaction induced by the lectin concanavalin A. Die Naturwissenschaften 1974; 61: 164
• 14 Shoham J, Sachs L. Differences in the binding of fluorescent concanavalin A to the surface membrane of normal and transformed cells. Proceedings of the National Academy of Sciences, U.S 1972; 69: 2479
• 15 Tollefsen D. M, Feagler J. R, Majerus P. W. Induction of the platelet release reaction by phytohemagglutinin. Journal of Clinical Investigation 1974; 53: 211
• 16 Warren L. The thiobarbituric acid assay of sialic acids. Journal of Biological Chemistry 1959; 234: 1971