Fractionation of human albumin during adsorption of CR1-containing vesicles. Bound vesicles on beads and unbound supernatants were resuspended in PBS containing 1% Triton X-100 and ELISA was performed as described in the Materials and Methods. () The material bound to either 25 μL or 100 μL beads bearing anti-CR1 peptide IgG (Immune) or to 25 μL or 100 μL beads bearing nonimmune rabbit IgG (Non-Imm). γ-Band and material unbound (▪) to beads were also included to compare the efficiency of isolation. The volume of each sample was adjusted back to the same volume as the initially applied γ-band to allow direct comparison. The results shown are the mean ± SEM of duplicate determinations from each of three separate experiments.