Immunoreactivity of common red blood cell antigens in cytoskeleton-free red blood cell microvesicles

Cytoskeleton-free microvesicles can be generated from normal red blood cells (RBCs). These RBC vesicles maintain a representative sampling of the lipid bilayer and several membrane proteins. We investigated RBC antigen segregation and persistence of immunoreactivity in RBC microvesicles.

Cytoskeleton-free RBC microvesicles were generated from erythrocytes expressing known RBC antigens. Antigen segregation into vesicles was documented by immunospecific antigen-antibody binding using IgG eluates and 125I Protein A. 125I Protein A counts per minute (cpm) ratios between antigen-positive vesicles sensitized with 11 eluates compared with those of vesicles incubated with normal human serum are reported.

Cytoskeleton-free RBC microvesicles preserved the antigenic expression of the original RBC's. Differences in cpm between eluate-sensitized vesicles and those incubated with normal human serum ranged from 3:1 for the Fy(b) antigen to 65:1 for the D antigen.

This study demonstrates that molecules bearing common RBC antigens segregate into microvesicles, fully preserving their epitope-bearing activity. The major proteins of the RBC cytoskeleton are not required for such antigen expression.