Effects of ageing, surface sialic acid and glycopeptides of erythrocytes on auto-rosettes in man.

Human red blood cells can bind in vitro to autologous peripheral blood lymphocytes forming auto-rosettes. The percentage of rosett-forming cells (A-RFC) depends on erythrocyte ageing in vivo. Old untreated cells given an A-RFC percentage lower as compared with the young ones. The same age groups of cells treated with neuraminidase show a parallel increase of A-RFC as compared with untreated cells. No significant difference is found between young and old cells with high concentrations of neuraminidase. The rosetting formation is inhibited by the pre-treatment of lymphocytes with erythrocyte glycopeptides released by trypsin. This suggests that auto-rosetting is mediated by erythrocyte surface glycopeptides in which sialic acid plays a role directly or not.