CHANGES IN THYMOCYTE REACTIVITY TO LECTINS INDUCED BY B-CELL MITOGENS OF TYPE OF SULFATED POLYANIONS

Abstract

Dextran sulfate, polyvinyl sulfate and carrageenan (but not the other polyanions tested, such as poly I:poly C, poly-L-glutamic acid or Escherichia coli lipopolysaccharide) act synergistically with phytohemagglutinin on mouse thymocyte stimulation, as measured by thymidine uptake and blast cell transformation. The active compounds shift the dose response of thymocytes to concanavalin A. The effect could be observed in 4 different strains of mice tested by using normal or cortisone-resistant thymocytes. Two possibilities are envisaged for explanation of these effects: attachment of polyanions by their anionic groups to cell surface constituents and interaction of the sulfate groups of the polymers with plant lectins; and modification of the cell membrane induced by sulfated polymers changing the binding capacity or the effectiveness of the membrane-associated events leading to thymocyte stimulation by the lectins.