Senescence of Canine Biotinylated Erythrocytes: Increased Autologous Immunoglobulin Binding Occurs on Erythrocytes Aged In Vivo

We have evaluated senescence related changes in canine red blood cells (RBCs) using the biotinylation system, where RBCs are labeled in vivo with biotin at the beginning of their life span, and retrieved from circulation on immobilized avidin at the end of their life span. This approach avoids the controversial use of density gradient centrifugation to collect presumably old RBCs. Furthermore, the dog is an appropriate model for human RBC senescence because it has a low degree of random RBC loss and a similarly long RBC life span (1 10 days). Two dogs had 97% to 100% of their circulating RBCs biotinylated by infusion of N-hydroxysuccinimido biotin (Clontech, Palo Alto, CA; Calbiochem, La Jolla, CA) dissolved in dimethyl sulfoxide. At postbiotinylation days 104 and 107 for one dog and day 1 10 for the other dog, biotinylated RBCs were isolated by magnetic cell sorting and analyzed for the presence of autologous IgG using '251-labeled sheep-antidog IgG (SAD