Effects of CLT administration on erythrocyte lifespan for 4.1^-/- mice. Compared with healthy controls, 4.1^-/- erythrocytes have a markedly reduced half-life.20 Mice were treated with CLT at a dose of 80 mg/kg twice a day for 11 days. Biotinylation was carried out as described in “Materials and methods,” and animals were bled at specified times. The percentage of biotinylated erythrocytes was determined by flow cytometry and is shown here for 2 representative animals. Data were obtained from 3 untreated and 4 CLT-treated 4.1^-/- mice (7 days of treatment).