Monosaccharide inhibition of E-rosette formation

Abstract

The capacity of various monosaccharides in solution to block the attachment of sheep red blood cells to human lymphocytes to form E rosettes was assessed. d- or l-Mannose in a concentration of 50 ng/ml reversibly reduced E-rosette numbers by more than one-half: other saccharides were less effective or did not at all inhibit. Neuraminidase treatment of either red cells or lymphocytes enhanced rosette formation. Dextran also enhanced rosette formation, whereas mannan or galactan showed no effect. Treatment of lymphocytes with low concentrations of trypsin or glutaraldehyde completely abolished E-rosette formation; similarly treated sheep red cells could enter into rosette formation. Sheep red blood cells obtained from the same commercial supplier, but from different sheep, exhibited consistent, sometimes marked, differences in susceptibility to oligosaccharide inhibition of E-rosette formation. These data suggest that mannose-like determinants on trypsin-sensitive lymphocyte surface components interact with other carbohydrate determinants on the surface of red cells to form rosettes. Although specific surface glycosyl transferases may be implicated in this adherence, it is possible that nonspecific conformational reactions between carbohydrates may mediate rosette formation.