Western blot of PNS, γ-band, and fractions from vesicle isolation experiments using immune or nonimmune beads. For the detection of CR1 (MW = ∼205 kD) and α-chain of CR3 (MW = 165 kD), samples were run on a 7% SDS-PAGE and transferred onto nitrocellulose filters. CR1 and CR3 in the figure are shown on portion of blot above 117 kD, as determined by the marker β-galactosidase. For the detection of FcγRIII (MW = 50 to 70 kD), albumin (HSA; MW = 67 kD), DAF (MW = 70 kD), and HLA class I (MW = 46 kD), samples were run on a 10% SDS-PAGE and transferred onto nitrocelluose filters (refer to the Materials and Methods for details). FcγRIII, albumin, and DAF in the figure represent the portion of the blot between 101 kD and 35 kD, as determined by the markers phosphorylase B and carbonic anhydrase. HLA class I in the figure represents the portion of the blot between 50 kD and 35 kD, as determined by the markers ovalbumin and carbonic anhydrase. The volume of each sample was adjusted to equal the volume of γ-band applied to allow direct comparisons.