Cell surface changes accompanying aging in human diploid fibroblasts: II. Two types of age-related changes revealed by concanavalin A-mediated red blood cell adsorption

Abstract

Age-related changes in cell surfaces of human diploid fibroblasts (TIG-1) were investigated using the concanavalin A (ConA)-mediated red blood cell (RBC) adsorption assay. When ConA-coated RBCs were adsorbed to fibroblasts (RBC coating method), the amount of RBCs adsorbed per mg of fibroblast protein increased continuously from the early phases of cell passage up through cell senescence. On the other hand, when RBCs were adsorbed to ConA-coated fibroblasts (fibroblast coating method), RBC adsorption did not occur throughout phase II and increased with the advance of phase III. [ 3H]ConA binding to fibroblasts, however, did not change with aging to the extent that could explain the observed changes in RBC adsorption. These age-related characteristics in RBC adsorption and [ 3H]ConA binding were also observed for WI38 and IMR-90 cells. In addition, SV40- and 60Co-transformed WI38 cells showed a close resemblance in their RBC adsorption capacity to early phase III cells. RBC adsorption with both the RBC and fibroblast coating methods was not a function of cell cycle phase and time spent in culture (metabolic time). Co-culturing of young cells with old or transformed cells did not affect the RBC adsorption capacity of respective cells. These results suggest that RBC adsorption with the RBC and fibroblast coating methods may represent cell surface markers for division age and senescence of aging human diploid cells.