Lectin-binding and spontaneous capping characteristics of the thymocyte glycophorin-like glycoprotein.

Monoclonal antibodies against lymphocyte glycoproteins have been used to identify the membrane molecules which bind peanut (PNA) and Helix pomatia (HPA) agglutinins and cap spontaneously on the uropod of polarized rat and mouse thymocytes. On the basis of co-capping experiments and radiolabelling of isolated glycoproteins after sodium dodecylsulfate polyacrylamide electrophoresis (SDS-PAGE), the major HPA- and PNA-binding sialoglycoprotein (with an apparent molecular weight of about 105 K; (1K = 10(3] 125-135 K after neuraminidase treatment) appears to be identical with the thymocyte glycophorin-like protein described by Brown et al. [11] and to correspond to the spontaneously capping component. Components of the mouse T200 (or rat 'leukocyte common antigen') differentiation antigen group also bind PNA (and partially HPA), but are unable to cap spontaneously. Some similarities in the redistribution behaviour of thymocyte and erythrocyte glycoproteins are discussed.