Biotinylated erythrocytes: in vivo survival and in vitro recovery

Rabbit erythrocytes were biotinylated by reaction with N-hydroxysuccinimidobiotin; the average level of biotinylation was 25,000 molecules per erythrocyte. These biotinylated cells exhibited a normal survival rate when reinfused into rabbits. Two studies demonstrated that the biotin label was stable in vivo. The first was a double-labeling experiment where the biotinylated erythrocytes were also labeled with 14C-cyanate; on reinfusion, the loss of biotinylated erythrocytes and 14C-cyanate label occurred in unison. The second study demonstrated that biotinylated erythrocytes that had been reinfused into rabbits could later be selectively isolated by attachment to an avidin support. This technique will facilitate a variety of studies that require the ability to label a specific cohort of cells in vitro and then reisolate those same cells after in vivo recirculation.